Livestock grazing impact on soil wettability and erosion risk in post-fire agricultural lands.

PubMed

Stavi, Ilan; Barkai, Daniel; Knoll, Yaakov M; Zaady, Eli

2016-12-15

Fires in agricultural areas are common, modifying the functioning of agro-ecosystems. Such fires have been extensively studied, and reported to considerably affect soil properties. Yet, understanding of the impact of livestock grazing, or more precisely, trampling, in fire-affected lands is limited. The objective of this study was to assess the impact of low- to moderate-fire severity and livestock trampling (hoof action) on the solid soil's wettability and related properties, and on soil detachment, in burnt vs. non-burnt croplands. The study was implemented by allowing livestock to access plots under high, medium, and low stocking rates in (unintentionally) burnt and non-burnt lands. Also, livestock exclusion plots were assigned as a control treatment. Results showed that fire slightly decreased the soil wettability. At the same time, water drop penetration time (WDPT) was negatively related to the stocking rate, and critical surface tension (CST) was ~13% smaller in the control plots than in the livestock-presence treatments. Also, the results showed that following burning, the resistance of soil to shear decreased by ~70%. Mass of detached material was similar in the control plots of the burnt and non-burnt plots. At the same time, it was three-, eight-, and nine-fold greater in the plots of the burnt×low, burnt×medium, and burnt×high stocking rates, respectively, than in the corresponding non-burnt ones. This study shows that livestock trampling in low- to moderate-intensity fire-affected lands increased the shearing of the ground surface layer. On the one hand, this slightly increased soil wettability. On the other hand, this impact considerably increased risks of soil erosion and land degradation. Copyright © 2016 Elsevier B.V. All rights reserved.

Impacts of fire on sources of soil CO2 efflux in a dry Amazon rain forest.

PubMed

Metcalfe, Daniel B; Rocha, Wanderley; Balch, Jennifer K; Brando, Paulo M; Doughty, Christopher E; Malhi, Yadvinder

2018-05-10

Fire at the dry southern margin of the Amazon rainforest could have major consequences for regional soil carbon (C) storage and ecosystem carbon dioxide (CO 2 ) emissions, but relatively little information exists about impacts of fire on soil C cycling within this sensitive ecotone. We measured CO 2 effluxes from different soil components (ground surface litter, roots, mycorrhizae, soil organic matter) at a large-scale burn experiment designed to simulate a severe but realistic potential future scenario for the region (Fire plot) in Mato Grosso, Brazil, over one year, and compared these measurements to replicated data from a nearby, unmodified Control plot. After four burns over five years, soil CO 2 efflux (R s ) was ~ 5.5 t C ha -1 yr -1 lower on the Fire plot compared to the Control. Most of the Fire plot R s reduction was specifically due to lower ground surface litter and root respiration. Mycorrhizal respiration on both plots was around ~ 20% of R s . Soil surface temperature appeared to be more important than moisture as a driver of seasonal patterns in R s at the site. Regular fire events decreased the seasonality of R s at the study site, due to apparent differences in environmental sensitivities among biotic and abiotic soil components. These findings may contribute towards improved predictions of the amount and temporal pattern of C emissions across the large areas of tropical forest facing increasing fire disturbances associated with climate change and human activities. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Soil microbiological properties and enzymatic activities of long-term post-fire recovery in dry and semiarid Aleppo pine (Pinus halepensis M.) forest stands

NASA Astrophysics Data System (ADS)

Hedo, J.; Lucas-Borja, M. E.; Wic, C.; Andrés-Abellán, M.; de Las Heras, J.

2015-02-01

Wildfires affecting forest ecosystems and post-fire silvicultural treatments may cause considerable changes in soil properties. The capacity of different microbial groups to recolonise soil after disturbances is crucial for proper soil functioning. The aim of this work was to investigate some microbial soil properties and enzyme activities in semiarid and dry Aleppo pine (Pinus halepensis M.) forest stands. Different plots affected by a wildfire event 17 years ago without or with post-fire silvicultural treatments 5 years after the fire event were selected. A mature Aleppo pine stand, unaffected by wildfire and not thinned was used as a control. Physicochemical soil properties (soil texture, pH, carbonates, organic matter, electrical conductivity, total N and P), soil enzymes (urease, phosphatase, β-glucosidase and dehydrogenase activities), soil respiration and soil microbial biomass carbon were analysed in the selected forests areas and plots. The main finding was that long time after this fire event produces no differences in the microbiological soil properties and enzyme activities of soil after comparing burned and thinned, burned and not thinned, and mature plots. Moreover, significant site variation was generally seen in soil enzyme activities and microbiological parameters. We conclude that total vegetation recovery normalises post-fire soil microbial parameters, and that wildfire and post-fire silvicultural treatments are not significant factors affecting soil properties after 17 years.

Radiocarbon of Respired CO2 Following Fire in Alaskan Boreal Forest: Can Disturbance Release Old Soil Carbon to the Atmosphere?

NASA Astrophysics Data System (ADS)

Schuur, E. A.; Randerson, J. A.; Fessenden, J.; Trumbore, S. E.

2002-12-01

Fire in the boreal forest releases carbon stored in vegetation and soil to the atmosphere. Following fire, microbial decomposition is stimulated by inputs of plant detritus and changes in soil microclimate, which can result in large losses of carbon. Furthermore, warmer summer soil temperatures and deeper thaw depths in burned ecosystems may make carbon that was previously climatically protected by low soil temperatures susceptible to decomposition. We used radiocarbon measurements to estimate the age of carbon released by soil respiration following fire in two black spruce (Picea mariana) forests in interior Alaska that burned during the summer of 1999. To isolate soil respiration, we established manipulated plots where vegetation was prevented from recolonizing, and paired control plots in nearby unburned forest. Soil respiration radiocarbon signatures in the burned manipulation ranged from +112\\permil to +192\\permil and differed significantly from the unburned controls that ranged from +100\\permil to +130\\permil. Burned plots appear to respire older carbon than unburned forest, which could either be due to the stimulation of decomposition of intermediate age soil organic matter pools, to the lack of plant respiration that reflects the atmospheric radiocarbon signature of +92\\permil, or both. At least during the initial phase following fire, these data suggest that carbon fluxes from soil are dominated by soil organic matter pools with decadal scale turnover times.

Bacterial and fungal growth for monitoring the impact of wildfire combined or not with different soil stabilization treatments

NASA Astrophysics Data System (ADS)

Barreiro, Ana; Baath, Erland; Díaz-Raviña, Montserrat

2015-04-01

Soil stabilization techniques are rapidly gaining acceptance as efficient tool for reducing post-fire erosion. However, despite its interest, information concerning their impact on soil biota is scarce. We examined, under field conditions, the bacterial and fungal medium-term responses in a hillslope area located in Laza (NW Spain) affected by a high severity wildfire with the following treatments established by triplicate (4 x 20 m plots): unburnt control soil, burnt control soil, burnt soil with rye seeding and burnt soil with straw mulch. The bacterial and fungal growth, as well as respiration, were measured 4 years after fire and application of treatments using leucine incorporation for bacterial growth and acetate-in-ergosterol incorporation for fungal growth. The results showed that soil respiration and fungal biomass were negatively affected by fire, in the top layer (0-5 cm), while bacterial and fungal growth was stimulated. These microbial changes induced by fire were associated with modifications in organic matter (50% reduction in C content) and soil pH (increase of 0.5-0.9 units). Thus, the results suggested that under acid environment (pH in water 3.5) post-fire conditions might have favoured both microbial groups, which is supported by the fact that estimated bacterial and fungal growth were positive and significant correlated with soil pH (range of 3.5-4.5). This contrast with the well-known reported investigations showing that bacteria rather than fungi proliferation occurred after prescribed fire or wildfire; it should be noticed, however, that soils with a higher pH than that in the present study were used. Our data also indicated that bacterial and fungal communities were not significantly affected by seeding and mulching treatments. The results highlighted the importance of pre-fire soil pH as key factor in determining the microbial response after fire. Acknowledgements. A. Barreiro is recipient of FPU grant from Spanish Ministry of Education. Keywords: wildfire, seeding, mulching, bacterial growth, fungal growth

Effects of high- and low-intensity fires on soil properties and plant growth in a Bolivian dry forest

Treesearch

Deborah K. Kennard; H.L. Gholz

2001-01-01

We compared soil nutrient availabiiity and soil physical properties among four treatments (high-intensity fire, low- intensity fire, plant removal, and harvesting gap) and a control (intact forest understory) over a period of 18 months in a tropical dry forest in Bolivia. The effect of treatments on plant growth was tested using a shade intolerant tree species (

Modeling soil thermal and carbon dynamics of a fire chronosequence in interior Alaska

USGS Publications Warehouse

Zhuang, Q.; McGuire, A.D.; O'Neill, K. P.; Harden, J.W.; Romanovsky, V.E.; Yarie, J.

2003-01-01

In this study, the dynamics of soil thermal, hydrologic, and ecosystem processes were coupled to project how the carbon budgets of boreal forests will respond to changes in atmospheric CO2, climate, and fire disturbance. The ability of the model to simulate gross primary production and ecosystem respiration was verified for a mature black spruce ecosystem in Canada, the age-dependent pattern of the simulated vegetation carbon was verified with inventory data on aboveground growth of Alaskan black spruce forests, and the model was applied to a postfire chronosequence in interior Alaska. The comparison between the simulated soil temperature and field-based estimates during the growing season (May to September) of 1997 revealed that the model was able to accurately simulate monthly temperatures at 10 cm (R > 0.93) for control and burned stands of the fire chronosequence. Similarly, the simulated and field-based estimates of soil respiration for control and burned stands were correlated (R = 0.84 and 0.74 for control and burned stands, respectively). The simulated and observed decadal to century-scale dynamics of soil temperature and carbon dynamics, which are represented by mean monthly values of these variables during the growing season, were correlated among stands (R = 0.93 and 0.71 for soil temperature at 20- and 10-cm depths, R = 0.95 and 0.91 for soil respiration and soil carbon, respectively). Sensitivity analyses indicate that along with differences in fire and climate history a number of other factors influence the response of carbon dynamics to fire disturbance. These factors include nitrogen fixation, the growth of moss, changes in the depth of the organic layer, soil drainage, and fire severity.

Post-fire drought effects and their legacy on soil functionality and microbial community structure in a Mediterranean shrubland

NASA Astrophysics Data System (ADS)

Belen Hinojosa, M.; Parra, Antonio; Laudicina, V. Armando; Moreno, José M.

2017-04-01

Climate change in subtropical areas, like the Mediterranean, is projected to decrease precipitation and to lengthen the seasonal drought period. Fire danger is also projected to increase under the most severe conditions. Little is known about the effects of increasing drought and, particularly, its legacy when precipitation resumes to normal, on the recovery of burned ecosystems. Here we studied the effects of post-fire drought and its legacy two years after it stopped on soil microbial community structure and functionality of a Cistus-Erica shrubland. To do this, a manipulative experiment was setup in which rainfall total patterns were modified by means of a rain-out shelters and irrigation system in a fully replicated set of previously burned plots. The treatments were: environmental control (natural rainfall), historical control (average rainfall, 2 months drought), moderate drought (25% reduction of historical control, 5 months drought) and severe drought (45% reduction, 7 months drought). One set of unburned plots under natural rainfall served as an additional control. Availability of the main soil nutrients and microbial community composition and functionality were monitored over 4 years under these rainfall manipulation treatments. Thereafter, treatments were discontinued and plots were subjected to ambient rainfall for two additional years. Post-fire drought had not effect on total C or N. Fire increased soil P and N availability. However, post-fire drought reduced available soil P and increased nitrate in the short term. Post- fire reduction of available K was accentuated by continued drought. Fire significantly reduced soil organic matter, enzyme activities and carbon mineralization, mainly in drought treated soils. Fire also decreased soil microbial biomass and the proportion of fungi, while that of actinomycetes increased in the short term. Post-fire drought accentuated the decrease of soil total microbial biomass and fungi, with bacteria becoming more abundant. After discontinuing the drought treatments, the effect of the previous drought was significant for available P and enzyme activities. Although the microbial biomass did not show a drought legacy effect of the previous drought period, the proportion of fungi was still lower in post-fire drought treatments and the proportion of bacteria (mainly Gram+) higher. Our results show that post-fire drought had an effect on soil functionality and microbial community structure, and that once the drought ceased its effects on some biogeochemical constituents and microbial groups were still visible two years thereafter. The fact that in a lapse of two years some variables had resume to normal while others still differed among drought treatment signifies that the legacies will last for some additional years, impairing during this time the normal functioning of the soil. However, these legacy was related to the magnitude of drought and, although not tested in our study, on the time since the occurrence of the phenomenon, and the sensitivity of the ecological system.

Impact of a long-term fire retardant (Fire Trol 931) on the leaching of Ca, Mg, and K from a Mediterranean forest loamy soil.

PubMed

Michalopoulos, Charalampos; Koufopoulou, Sofia; Tzamtzis, Nikolaos; Pappa, Athina

2016-03-01

The present laboratory study was conducted in pot soil taken from forest. The leaching of calcium (Ca), magnesium (Mg), and potassium (K) (plant macronutrients) due to the application of a nitrogen phosphate-based long-term fire retardant (LTFR) (Fire Trol 931) was investigated. The concentrations of Ca(2+), Mg(2+), and K(+) were measured in the resulting leachates from pots with forest soil and pine tree alone and in combination with fire. Magnesium is a minor component of Fire Trol 931. The leaching of Ca(2+), Mg(2+), and K(+) from treated soils with the retardant pots was significantly greater than that from control pots. The leaching of Mg(2+) was found to be of small percentage of the initially applied Mg quantities. Fire Trol 931 application resulted in the leaching of Ca(2+), Mg(2+), and K(+) from a typical Mediterranean forest soil in pots, following the application of simulated annual precipitation probably due to ammonium (one of the major retardant components) soil deposition that mobilizes base cations from the soil. It seems that LTFR application may result in chemical leaching from the soil to the drainage water.

Exploring the sensitivity of soil carbon dynamics to climate change, fire disturbance and permafrost thaw in a black spruce ecosystem

USGS Publications Warehouse

O'Donnell, J. A.; Harden, J.W.; McGuire, A.D.; Romanovsky, V.E.

2011-01-01

In the boreal region, soil organic carbon (OC) dynamics are strongly governed by the interaction between wildfire and permafrost. Using a combination of field measurements, numerical modeling of soil thermal dynamics, and mass-balance modeling of OC dynamics, we tested the sensitivity of soil OC storage to a suite of individual climate factors (air temperature, soil moisture, and snow depth) and fire severity. We also conducted sensitivity analyses to explore the combined effects of fire-soil moisture interactions and snow seasonality on OC storage. OC losses were calculated as the difference in OC stocks after three fire cycles (???500 yr) following a prescribed step-change in climate and/or fire. Across single-factor scenarios, our findings indicate that warmer air temperatures resulted in the largest relative soil OC losses (???5.3 kg C mg-2), whereas dry soil conditions alone (in the absence of wildfire) resulted in the smallest carbon losses (???0.1 kg C mg-2). Increased fire severity resulted in carbon loss of ???3.3 kg C mg-2, whereas changes in snow depth resulted in smaller OC losses (2.1-2.2 kg C mg-2). Across multiple climate factors, we observed larger OC losses than for single-factor scenarios. For instance, high fire severity regime associated with warmer and drier conditions resulted in OC losses of ???6.1 kg C mg-2, whereas a low fire severity regime associated with warmer and wetter conditions resulted in OC losses of ???5.6 kg C mg-2. A longer snow-free season associated with future warming resulted in OC losses of ???5.4 kg C mg-2. Soil climate was the dominant control on soil OC loss, governing the sensitivity of microbial decomposers to fluctuations in temperature and soil moisture; this control, in turn, is governed by interannual changes in active layer depth. Transitional responses of the active layer depth to fire regimes also contributed to OC losses, primarily by determining the proportion of OC into frozen and unfrozen soil layers. ?? 2011 Author(s).

Quantifying soil surface change in degraded drylands: shrub encroachment and effects of fire and vegetation removal in a desert grassland

USGS Publications Warehouse

Sankey, Joel B.; Ravi, Sujith; Wallace, Cynthia S.A.; Webb, Robert H.; Huxman, Travis E.

2012-01-01

Woody plant encroachment, a worldwide phenomenon, is a major driver of land degradation in desert grasslands. Woody plant encroachment by shrub functional types ultimately leads to the formation of a patchy landscape with fertile shrub patches interspaced with nutrient-depleted bare soil patches. This is considered to be an irreversible process of land and soil degradation. Recent studies have indicated that in the early stages of shrub encroachment, when there is sufficient herbaceous connectivity, fires (prescribed or natural) might provide some reversibility to the shrub encroachment process by negatively affecting shrub demography and homogenizing soil resources across patches within weeks to months after burning. A comprehensive understanding of longer term changes in microtopography and spatial patterning of soil properties following fire in shrub-encroached grasslands is desirable. Here, we investigate the changes in microtopography with LiDAR (light detection and ranging), vegetation recovery, and spatial pattering of soil properties in replicated burned, clipped, and control areas in a shrub-grass transition zone in the northern Chihuahuan Desert four years after prescribed fire or clipping. Results indicate a greater homogeneity in soil, microtopography, and vegetation patterning on burned relative to clipped and control treatments. Findings provide further evidence that disturbance by prescribed fire may allow for reversal of the shrub encroachment process, if the event occurs in the early stages of the vegetation shift. Improved understanding of longer-term effects of fire and associated changes in soil patterning can inform the use and role of fire in the context of changing disturbance regimes and climate.

Soil microbiological properties and enzymatic activities of long-term post-fire recovery in dry and semiarid Aleppo pine (Pinus halepensis M.) forest stands

NASA Astrophysics Data System (ADS)

Hedo, J.; Lucas-Borja, M. E.; Wic, C.; Andrés Abellán, M.; de Las Heras, J.

2014-10-01

Wildfires affecting forest ecosystems and post-fire silvicultural treatments may cause considerable changes in soil properties. The capacity of different microbial groups to recolonize soil after disturbances is crucial for proper soil functioning. The aim of this work was to investigate some microbial soil properties and enzyme activities in semiarid and dry Aleppo pine (Pinus halepensis M.) forest stands. Different plots affected by a wildfire event 17 years ago without or with post-fire silvicultural treatments five years after the fire event were selected. A mature Aleppo pine stand unaffected by wildfire and not thinned was used as a control. Physicochemical soil properties (soil texture, pH, carbonates, organic matter, electrical conductivity, total N and P), soil enzymes (urease, phosphatase, β-glucosidase and dehydrogenase activities), soil respiration and soil microbial biomass carbon were analysed in the selected forests areas and plots. The main finding was that long time after this fire event produces no differences in the microbiological soil properties and enzyme activities of soil after comparing burned and thinned, burned and not thinned, and mature plots. Thus, the long-term consequences and post-fire silvicultural management in the form of thinning have a significant effect on the site recovery after fire. Moreover, significant site variation was generally seen in soil enzyme activities and microbiological parameters. We conclude that total vegetation restoration normalises microbial parameters, and that wildfire and post-fire silvicultural treatments are not significant factors of soil properties after 17 years.

Effects of controlled burns on the bulk density and thermal conductivity of soils at a southern Colorado site

Treesearch

W. J. Massman; J. M. Frank

2006-01-01

Throughout the world fire plays an important role in the management and maintenance of ecosystems. However, if a fire is sufficiently intense, soil can be irreversibly altered and the ability of vegetation, particularly forests, to recover after a fire can be seriously compromised. Because fire is frequently used by land managers to reduce surface fuels, it is...

Effects of fire alone or combined with thinning on tissue nutrient concentrations and nutrient resorption in Desmodium nudiflorum.

PubMed

Huang, Jianjun; Boerner, Ralph E J

2007-08-01

This study examined tissue nutrient responses of Desmodium nudiflorum to changes in soil total inorganic nitrogen (TIN) and available phosphorus (P) that occurred as the result of the application of alternative forest management strategies, namely (1) prescribed low-intensity fire (B), (2) overstory thinning followed by prescribed fire (T + B), and (3) untreated control C), in two Quercus-dominated forests in the State of Ohio, USA. In the fourth growing season after a first fire, TIN was significantly greater in the control plots (9.8 mg/kg) than in the B (5.5 mg/kg) and T + B (6.4 mg/kg) plots. Similarly, available P was greater in the control sites (101 microg/g) than in the B (45 microg/kg) and T + B (65 microg/kg) sites. Leaf phosphorus ([P]) was higher in the plants from control site (1.86 mg/g) than in either the B (1.77 mg/g) or T + B plants (1.73 mg/g). Leaf nitrogen ([N]) and root [N] showed significant site-treatment interactive effects, while stem [N], stem [P], and root [P] did not differ significantly among treatments. During the first growing season after a second fire, leaf [N], stem [N], litter [P] and available soil [P] were consistently lower in plots of the manipulated treatments than in the unmanaged control plot, whereas the B and T + B plots did not differ significantly from each other. N resorption efficiency was positively correlated with the initial foliar [N] in the manipulated (B and T + B) sites, but there was no such relation in the unmanaged control plots. P resorption efficiency was positively correlated with the initial leaf [P] in both the control and manipulated plots. Leaf nutrient status was strongly influenced by soil nutrient availability shortly after fire, but became more influenced by topographic position in the fourth year after fire. Nutrient resorption efficiency was independent of soil nutrient availability. These findings enrich our understanding of the effects of ecosystem restoration treatments on soil nutrient availability, plant nutrient relations, and plant-soil interactions at different temporal scales.

Fungal role in post-fire ecosystem recovery in Sierra Nevada National Park (Spain)

NASA Astrophysics Data System (ADS)

Bárcenas-Moreno, Gema; Jiménez-Morillo, Nicasio T.; Mataix-Beneyto, Jorge; Martín Sánchez, Ines

2016-04-01

Fire effect on soil microorganisms has been studies for decades in several ecosystems and different microbial response can be found in the bibliography depending on numerous intrinsic and extrinsic soil factors. These factors will determine preliminary soil microbial community composition, subsequent pos-fire initial colonizers and even post-fire growth media characteristics that microbial community will find to start recolonisation. Fire-induced soil bacterial proliferation is a common pattern found after fire, usually related to pH and C availability increased. But when original soil pH is not altered by fire in acid soils, microbial response can be different and fungal response can be crucial to ecosystem recovery. In this study we have compile data related to high mountain soil from Sierra Nevada National park which was affected by a wildfire in 2006 and data obtained by laboratory heating experiment, trying to elucidate the ecological role of fungi in this fragile ecosystem. On the one hand we can observe fire-induced fungal abundance proliferation estimated by plate count method 8 and 32 months after wildfire and even in a short-term (21 d) after laboratory heating at 300 °C. Six years after fire, fungal abundance was similar between samples collected in burnt and unburnt-control area but we found higher proportion of species capable to degrade PAHs (lacase activity) in burnt soil than I the unburnt one. This finding evidences the crucial role of fungal enzymatic capacities to detoxify burnt soils when fire-induced recalcitrant and even toxic carbon compounds could be partially limiting total ecosystem recovery.

Wildfire mitigation strategies affect soil enzyme activity and soil organic carbon in loblolly pine (Pinus taeda) forests

Treesearch

R.E.J. Boerner; T.A. Waldrop; V.B. Shelburne

2006-01-01

We quantified the effects of three wildfire hazard reduction treatments (prescribed fire, thinning from below, and the combination of fire and thinning), and passive management (control) on mineral soil organic C, and enzyme activity in loblolly pine (Pinus taeda L.) forests on the Piedmont of South Carolina. Soil organic C was reduced by thinning,...

Effects of Fire on the Plant-Soil Interactions in Northern Chihuahuan Desert

NASA Astrophysics Data System (ADS)

Wang, G.; Li, J. J.; Ravi, S.; Sankey, J. B.; Theiling, B. P.; Dukes, D.; Gonzales, H. B.; Van Pelt, R. S.

2017-12-01

Desert grasslands in the southwestern US have undergone dramatic land degradation with woody shrub encroachment over the last 150 years. Soil carbon (C), nitrogen (N) and other soil nutrients are redistributed among shrubs, grasses, and bare interspaces during encroachment. Several studies suggest that periodic fire favors the homogenization of soil resources and can provide a certain form of reversibility for the shrub-grass transition. In this study, we used manipulative field experiments to investigate the influence of fire on the isotope composition of C (δ13C) and N (δ15N) in bare interspace, grass and shrub microsites. Replicated burned and control (unburned) experimental plots (5 m × 5 m) were set up in a desert grassland in northern Chihuahuan Desert in March 2016. In each plot, a total of 50 randomly-distributed surface soil samples, with their microsite types accurately recorded, were collected twice per year in March and June (before and after the windy season). δ13C and δ15N in the soil samples were analyzed. Our results show that fire has changed soil δ13C and δ15N after two windy seasons, especially in the shrub microsite. For example, δ13C increased from -18.8‰ to -17.0‰ after a windy season in soils under burned shrub canopies, and increased to -14.3‰ in Mar. 2017, one year after the prescribed fire. In contrast, it changed notably from -14.6‰ to -17.6‰ under shrub canopies in the control plot during the same period of time. For soil δ15N, it decreased slightly from 6.1‰ to 5.6‰ within a year after the prescribed fire in shrub microsite, and a comparable decline was also observed in the same type of microsite of the control plot. Because the average δ13C value of C4 plant tissue (-12‰) is distinct from C3 plants (-26‰), the increase of soil δ13C suggests that the relative contribution of soil organic matter under shrub canopies from shrubs (C3 plants) decreased after a burning event compared to grasses (C4 plants). The insignificant change of soil δ15N in shrub microsite indicates that soil mineralization rates and plant N uptake under shrub canopies may not be substantially altered by the prescribed fire. Our results highlighted that fire can change the resource interactions between soil and plants, which may further affect the shrub encroachment process as well as the dynamics of grassland-shrubland ecosystem.

Temporal changes in soil water repellency after a forest fire in a Mediterranean calcareous soil: Influence of ash and different vegetation type.

PubMed

Jiménez-Pinilla, P; Lozano, E; Mataix-Solera, J; Arcenegui, V; Jordán, A; Zavala, L M

2016-12-01

Forest fires usually modify soil water repellency (SWR), and its persistence and intensity show a high variability both in space and time. This research studies the evolution of SWR in a Mediterranean calcareous soil affected by a forest fire, which occurred in Gorga (SE Spain) in July 2011, comparing the effect of the main vegetation cover between pine (Pinus halepensis) and shrubs species (Quercus coccifera, Rosmarinus officinalis, Cistus albidus, Erica arborea and Brachypodium retusum) and the relationship with soil moisture content (SMC). Also the study analyzed the effect of ash on SWR dynamics under field conditions. Six plots were established on the fire-affected area and the unburned-control-adjacent area to monitoring SWR with the water drop penetration time (WDPT) test, SMC through moist sensors (5cm depth) and three different ash treatments: ash presence, ash absence and incorporation of ash into the soil. An immediate increase of SWR was observed in the fire-affected area, mainly in pine plots. SWR changes in control (unburned) plots were quite similar between different types of vegetation influence, despite higher SWR values being observed on pine plots during the study period. A noticeable decrease of SWR was observed during the first months after fire in the affected areas, especially after the first rainy period, both in pine and shrubs plots. SWR increase was registered in all plots, and the highest levels were in March 2012 in burned pine plots. SWR decrease was higher in plots where ash was removed. Fire-affected soils became wettable 1year and a half after the fire. Copyright © 2015 Elsevier B.V. All rights reserved.

Sensitivity of glomalin-related soil protein to wildfires: Immediate and medium-term changes.

PubMed

Lozano, Elena; Jiménez-Pinilla, Patricia; Mataix-Solera, Jorge; Arcenegui, Victoria; Mataix-Beneyto, Jorge

2016-12-01

Forest fires are part of many ecosystems, especially in the Mediterranean Basin. Depending on the fire severity, they can be a great disturbance, so it is of special importance to know their impact on the ecosystem elements. In this study, we measured the sensitivity of glomalin related soil protein (GRSP), a glycoprotein produced by arbuscular mycorrhizal fungi (AMF), to fire perturbation. Two wildfire-affected areas in the SE Spain (Gata and Gorga) were studied. Soil organic carbon (SOC) was also measured. Effects on GRSP immediately after fire were analyzed in both areas, while in Gorga a monitoring of GRSP stocks over a year period after the fire was also carried out. Soil samplings were carried out every 4months. Plots (1×2m 2 ) were installed beneath pines and shrubs in burned and an adjacent control area. Results of GRSP content immediately after a fire only showed significant differences for shrub plots (burned vs control) (p<0.01) in the Gorga site. However, a year of monitoring showed significant fire effect on GRSP content in both plot types (pines and shrubs). Control plots varied considerably over time, while in burned plots GRSP content remained constant during the whole studied period. This research provides evidence of the sensitivity of GRSP to a wildfire perturbation. Copyright © 2015 Elsevier B.V. All rights reserved.

Impact of postfire management on soil respiration and C concentration in a managed hemiboreal forest

NASA Astrophysics Data System (ADS)

Köster, Kajar; Seglinš, Katrin; Parro, Kristi; Metslaid, Marek

2017-04-01

Fire is the main natural disturbance in boreal forests and it is expected that its frequency will increase as a result of climate change. Fire is the primary process which organizes the physical and biological attributes of the boreal biome and influences energy flows and biogeochemical cycles, particularly the carbon (C) cycle. The objective of this study was to assess the impact of forest fire and time since forest fire on soil respiration and soil C concentrations in scenarios where the area was managed or was not managed after fire disturbance. This study was carried out in two permanent research areas in northwestern Estonia (hemiboreal forest zone) that were damaged by fire: Vihterpalu (59o13' N 23o49' E) and Nõva (59o10' N 23o45' E). Fire occurred in Vihterpalu in year 1992 (550 ha burned), when the forest was 52 years old, and in Nõva in year 2008 (800 ha burned), when the forest was 70 years old. Before the fire disturbance both sites were covered with planted or sown Scots pine (Pinus sylvestris L.) forests originally regenerated after heavy fires in 1940 (Nõva) and 1951 (Vihterpalu). In all areas we are dealing with stand replacing fires where all (or almost all) of the stand was destroyed by fire. In both study areas three different types of sample areas were set up: 1) control areas (CO), that are unburned and no management activities carried out; 2) burned and cleared (BC) with salvage logging, areas in which all dead and live trees were harvested from the plot after fire; 3) burned and uncleared areas (BU), areas without management in which both dead and live trees were left on the plots after fire disturbance. On every area three measuring transects (40 m long) were established where soil respiration (g CO2 m-2h-1) was measured on five collars, and five soil samples (0.5 m long and 0.05 m in diameter) were taken to estimate soil C (kg m-2) content. In our study, highest soil respiration values were recorded in control (CO) areas, which are not affected by forest fires. In the fire areas (BC and BU) the average soil respiration values were more than two times lower than in the areas which were not affected by forest fires. Different post-fire management activities (removing or leaving damaged trees) did not affect the soil respiration values. Soil temperature had a significant impact on the CO2 flows. The recorded average soil temperature was lowest in CO and highest in BU areas, respectively. In spring and autumn soil temperatures in disturbed areas, as well as in cleared areas, were rising faster than in CO areas. In our study, 1992 fire areas had thicker litter and organic layer compared to 2008 fire areas. Most of the litter and organic matter was found in CO areas, followed by BU and BC areas. The highest C concentrations were found in CO areas. In the fire areas C concentration was also affected by the post-disturbance management, as in BC areas soil C concentration was lower compared to BU areas.

The critical role of fire in catchment coevolution in South Eastern Australia

NASA Astrophysics Data System (ADS)

Nyman, P.; Inbar, A.; Lane, P. N. J.; Sheridan, G. J.

2016-12-01

Temperate south east Australian forested uplands are characterised by complex spatial patterns in forest types, soils and fire regimes, even within areas with similar geologies and landscape position. Preliminary measurements and experiments suggest that positive and negative feedbacks between the vegetation, fuels, fire frequency and soil erosion may control the coevolution of these observed system states. Here we propose the hypotheses that in this landscape post-fire soil erosion has played a dominant role in the coevolved system-state combinations of standing biomass, fire frequency and soil depth. To test the hypothesis a 1D simulation model was developed that links together an ecohydrological model to drive the biomass production and water and energy partitioning, a stochastic fire model that is controlled by climate, fuel load and moisture conditions, and a geomorphic model that controls soil production and fluvial and diffusive sediment transport rates. The model was calibrated to the range of existing observed quasi-equalibrium system-states of soil depth, standing biomass, fuel loading and fire frequency using field measurements from 12 instrumented eco-hydrologic microclimate research sites. The long-term partitioning of rainfall into evaporation, transpiration, and streamflow was calibrated against field and literature values. Fuel moisture and micro-climate variables were calibrated to the field microclimate stations. The calibrated model was able to reasonably replicate the observed quasi-equilibrium system-states and hydrologic outputs using current climate forcings operating over a 10,000 year period, providing confidence in the model structure and performance. The model was then used to test the hypothesis stated above, by alternatively including or excluding the post fire erosion process. An alternate hypothesis, whereby the observed system states are dominated by climate related differences in soil production rates was also tested in this way. The results support the hypothesis that feedbacks between fire, ecology, hydrology and geomorphology have played a critical role in the coevolution of south east Australian forested uplands. Similar pyro-eco-hydrologic feedbacks may play a critical role in catchment coevolution in other forested systems globally.

Impacts of single and recurrent wildfires on topsoil moisture regime

NASA Astrophysics Data System (ADS)

González-Pelayo, Oscar; Malvar, Maruxa; van den Elsen, Erik; Hosseini, Mohammadreza; Coelho, Celeste; Ritsema, Coen; Bautista, Susana; Keizer, Jacob

2017-04-01

The increasing fire recurrence on forest in the Mediterranean basin is well-established by future climate scenarios due to land use changes and climate predictions. By this, shifts on mature pine woodlands to shrub rangelands are of major importance on forest ecosystems buffer functions, since historical patterns of established vegetation help to recover from fire disturbances. This fact, together with the predicted expansion of the drought periods, will affect feedback processes of vegetation patterns since water availability on these seasons are driven by post-fire local soil properties. Although fire impacts of soil properties and water availability has been widely studied using the fire severity as the main factor, little research is developed on post-fire soil moisture patterns, including the fire recurrence as a key explanatory variable. The following research investigated, in pine woodlands of north central Portugal, the short-term consequences (one year after a fire) of wildfire recurrence on the surface soil moisture content (SMC) and on effective soil water (SWEFF, parameter that includes actual daily soil moisture, soil field capacity-FC and permanent wilting point-PWP). The study set-up includes analyses at two fire recurrence scenarios (1x- and 4x-burnt since 1975), at a patch level (shrub patch/interpatch) and at two soil depths (2.5 and 7.5 cm) in a nested approach. Understanding how fire recurrence affects water in soil over space and time is the main goal of this research. The use of soil moisture sensors in a nested approach, the rainfall features and analyses on basic soil properties as soil organic matter, texture, bulk density, pF curves, soil water repellency and soil surface components will establish which factors has the largest role in controlling soil moisture behavior. Main results displayed, in a seasonal and yearly basis, no differences on SMC as increasing fire recurrence (1x- vs 4x-burnt) neither between patch/interpatch microsites at both two soil depths. Otherwise, in a yearly basis and during soil drying cycles, it was found less effective water on soil at the surface layers of the 4x-burnt and between shrub interpatches, based on the worst soil hydrological conditions (PWP) and the increasing percentage of abiotic soil surface components as increasing fire recurrence. Our results suggest that the inclusion of soil hydrological properties, as pF-curves, on the soil water effectiveness calculation seems to be a better indicator of water availability that volumetric SM per se. Otherwise, the use of a nested approach methodology, stresses how fire recurrence, expected increases in the summer drought spells and, the increasing dominance of abiotic soil surface components, are the factors that much influence soil eco-hydrological functioning in fire prone ecosystems. Furthermore, this research point out how post-fire soil structural quality into plant interpatches could provoke looping feedback processes triggering desertification situations also in humid Mediterranean forestlands.

Post-fire recovery of soil organic matter in a Cambisol from typical Mediterranean forest in Southwestern Spain.

PubMed

Jiménez-González, Marco A; De la Rosa, José María; Jiménez-Morillo, Nicasio T; Almendros, Gonzalo; González-Pérez, José Antonio; Knicker, Heike

2016-12-01

Wildfire is a recurrent phenomenon in Mediterranean ecosystems and contributes to soil degradation and desertification, which are partially caused by alterations to soil organic matter (SOM). The SOM composition from a Cambisol under a Mediterranean forest affected by a wildfire is studied in detail in order to assess soil health status and better understand of soil recovery after the fire event. The soil was sampled one month and twenty-five months after the wildfire. A nearby unburnt site was taken as control soil. Soil rehabilitation actions involving heavy machinery to remove burnt vegetation were conducted sixteen months after the wildfire. Immediately after fire the SOM increased in topsoil due to inputs from charred vegetation, whereas a decrease was observed in the underlying soil layer. Twenty-five months after fire soil-pH increased in fire-affected topsoil due to the presence of ashes, a decrease in SOM content was recorded for the burnt topsoil and similar trend was observed for the water holding capacity. The pyro-chromatograms of burned soils revealed the formation of additional aromatic compounds. The thermal cracking of long-chain n-alkanes was also detected. Solid-state 13 C NMR spectroscopy supported the increase of aromatic compounds in the fire-affected topsoil due to the accumulation of charcoal, whereas the deeper soil sections were not affected by the fire. Two years later, soil parameters for the unburnt and burnt sites showed comparable values. The reduction of the relative intensity in the aromatic C region of the NMR spectra indicated a decrease in the charcoal content of the topsoil. Due to the negligible slope in the sampling site, the loss of charcoal was explained by the post-fire restoration activity, degradation, leaching of pyrogenic SOM into deeper soil horizons or wind erosion. Our results support that in the Mediterranean region, fire-induced alteration of the SOM is not lasting in the long-term. Copyright © 2016 Elsevier B.V. All rights reserved.

Deep Ion Torrent sequencing identifies soil fungal community shifts after frequent prescribed fires in a southeastern US forest ecosystem.

PubMed

Brown, Shawn P; Callaham, Mac A; Oliver, Alena K; Jumpponen, Ari

2013-12-01

Prescribed burning is a common management tool to control fuel loads, ground vegetation, and facilitate desirable game species. We evaluated soil fungal community responses to long-term prescribed fire treatments in a loblolly pine forest on the Piedmont of Georgia and utilized deep Internal Transcribed Spacer Region 1 (ITS1) amplicon sequencing afforded by the recent Ion Torrent Personal Genome Machine (PGM). These deep sequence data (19,000 + reads per sample after subsampling) indicate that frequent fires (3-year fire interval) shift soil fungus communities, whereas infrequent fires (6-year fire interval) permit system resetting to a state similar to that without prescribed fire. Furthermore, in nonmetric multidimensional scaling analyses, primarily ectomycorrhizal taxa were correlated with axes associated with long fire intervals, whereas soil saprobes tended to be correlated with the frequent fire recurrence. We conclude that (1) multiplexed Ion Torrent PGM analyses allow deep cost effective sequencing of fungal communities but may suffer from short read lengths and inconsistent sequence quality adjacent to the sequencing adaptor; (2) frequent prescribed fires elicit a shift in soil fungal communities; and (3) such shifts do not occur when fire intervals are longer. Our results emphasize the general responsiveness of these forests to management, and the importance of fire return intervals in meeting management objectives. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Impact of a long term fire retardant (Fire Trol 931) on the leaching of Na, Al, Fe, Mn, Cu and Si from a Mediterranean forest soil: a short-term, lab-scale study.

PubMed

Koufopoulou, Sofia; Michalopoulos, Charalampos; Tzamtzis, Nikolaos; Pappa, Athina

2014-06-01

Long term fire retardant (LTR) application for forest fire prevention purposes as well as wildland fires can result in chemical leaching from forest soils. Large quantities of sodium (Na), aluminium (Al), iron (Fe), manganese (Mn), copper (Cu) and silicon (Si) in leachates, mainly due to ammonium (one of the major LTR components) soil deposition, could affect the groundwater quality. The leaching of Na, Al, Fe, Mn, Cu and Si due to nitrogen based LTR application (Fire Trol 931) was studied at laboratory scale. The concentrations of Na(+), Al(3+), Fe(3+)/Fe(2+), Mn(2+), Cu(2+) and Si(4+) were measured in the resulting leachates from pots with forest soil and pine trees alone and in combination with fire. The leaching of Na, Fe and Si from treated pots was significantly greater than that from control pots. The leaching of Al, Mn and Cu was extremely low.

Fire impact and assessment of post-fire actions of a typical Mediterranean forest from SW Spain

NASA Astrophysics Data System (ADS)

Jiménez-González, Marco A.; María De la Rosa, José; Jiménez-Morillo, Nicasio T.; Zavala, Lorena M.; Knicker, Heike

2015-04-01

Wildfires may cause significant changes in soil physical and chemical properties. In addition, soil organic matter (SOM) content and chemical properties are usually affected by fire. Fire impacts may negatively affect soil health and quality, and induce or enhance runoff generation and, thereby, soil erosion risk and cause damages to the habitat of species. This fact is especially dramatic in Mediterranean ecosystems, where forest fires are a frequent phenomenon and restoration strategies are a key issue. The goals of this study are to determine: i) the immediate effects of fire on soil properties, including changes occurred in the quantity and quality of SOM and ii) the effect of post-fire actions on soil properties. In August 2012, a wildfire affected a forest area of approx. 90 ha in Montellano (Seville, SW Spain; longitude 37.00 °, latitude -5.56 °). This area is dominated by pines (Pinus pinaster and Pinus halepensis), and eucalypts (Eucaliptus globulus) with a Mediterranean climate. Dominant soil types are Rendzic Leptosols and Calcaric Haplic Regosols. It is a poorly limestone-developed soil (usually swallower than 25 cm). Four soil subsamples were collected 1 month and 25 months after fire within an area of approximately 200 m2. Subsamples were mixed together, homogenized, air-dried, crushed and sieved (2 mm). One control sample was collected in an adjacent area. The litter layer was removed by hand and studied separately. Branches, stems, bushes and plant residues on the fire-affected area were removed 16 months after the fire using heavy machinery as part of the post-fire management. The present research focuses on the study of the elemental composition (C, H and N) and physical properties (pH, water holding capacity, electrical conductivity) of bulk soil samples, and on the spectroscopic analysis (FT-IR, 13C NMR) and analytical pyrolysis data obtained from bulk the oils and from the humic acid fraction. immediate effects of fire, including the charring of vegetation and litter, as the input of charred residues may contribute to increase the total amount of soil organic matter. The post-fire removal of vegetation probably contributed to an additional loss of soil material due to an increase of the erosion risk. In addition, preliminary results point out that the burnt soil is not being recovered to the pre-fire conditions at a molecular level neither in the elemental composition. Results of this study will constitute a valuable tool for stake holders and decision makers to avoid additional alterations caused by post fire management of fire affected forests.

Rapid Shifts in Soil Nutrients and Decomposition Enzyme Activity in Early Succession Following Forest Fire

DOE PAGES

Knelman, Joseph E.; Graham, Emily B.; Ferrenberg, Scott; ...

2017-09-15

In post-disturbance landscapes nutrient availability has proven a major control on ecological succession. In this study, we examined variation in connections between soil nutrient availability and decomposition extracellular enzyme activity (EEA) across post fire secondary succession in forest soils as well as after a secondary flood disturbance. We also examined possible linkages between edaphic properties and bacterial communities based on 16S rRNA gene analysis. We found that with advancing succession in a post-fire landscape, the relationship between soil nutrients and EEA became stronger over time. In general, late successional soils showed stronger connections between EEA and soil nutrient status, whilemore » early successional soils were marked by a complete decoupling of nutrients and EEA. We also found that soil moisture and bacterial communities of post-fire disturbance soils were susceptible to change following the secondary flood disturbance, while undisturbed, reference forest soils were not. Our results demonstrate that nutrient pools correlating with EEA change over time. While past work has largely focused on ecosystem succession on decadal timescales, our work suggests that nutrients shift in their relative importance as a control of decomposition EEA in the earliest stages of secondary succession. Furthermore, this work emphasizes the relevance of successional stage, even on short timescales, in predicting rates of carbon and nitrogen cycling, especially as disturbances become more frequent in a rapidly changing world.« less

Rapid Shifts in Soil Nutrients and Decomposition Enzyme Activity in Early Succession Following Forest Fire

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knelman, Joseph E.; Graham, Emily B.; Ferrenberg, Scott

In post-disturbance landscapes nutrient availability has proven a major control on ecological succession. In this study, we examined variation in connections between soil nutrient availability and decomposition extracellular enzyme activity (EEA) across post fire secondary succession in forest soils as well as after a secondary flood disturbance. We also examined possible linkages between edaphic properties and bacterial communities based on 16S rRNA gene analysis. We found that with advancing succession in a post-fire landscape, the relationship between soil nutrients and EEA became stronger over time. In general, late successional soils showed stronger connections between EEA and soil nutrient status, whilemore » early successional soils were marked by a complete decoupling of nutrients and EEA. We also found that soil moisture and bacterial communities of post-fire disturbance soils were susceptible to change following the secondary flood disturbance, while undisturbed, reference forest soils were not. Our results demonstrate that nutrient pools correlating with EEA change over time. While past work has largely focused on ecosystem succession on decadal timescales, our work suggests that nutrients shift in their relative importance as a control of decomposition EEA in the earliest stages of secondary succession. Furthermore, this work emphasizes the relevance of successional stage, even on short timescales, in predicting rates of carbon and nitrogen cycling, especially as disturbances become more frequent in a rapidly changing world.« less

Effect of fire on phosphorus forms in Sphagnum moss and peat soils of ombrotrophic bogs.

PubMed

Wang, Guoping; Yu, Xiaofei; Bao, Kunshan; Xing, Wei; Gao, Chuanyu; Lin, Qianxin; Lu, Xianguo

2015-01-01

The effect of burning Sphagnum moss and peat on phosphorus forms was studied with controlled combustion in the laboratory. Two fire treatments, a light fire (250 °C) and a severe fire (600 °C), were performed in a muffle furnace with 1-h residence time to simulate the effects of different forest fire conditions. The results showed that fire burning Sphagnum moss and peat soils resulted in losses of organic phosphorus (Po), while inorganic phosphorus (Pi) concentrations increased. Burning significantly changed detailed phosphorus composition and availability, with severe fires destroying over 90% of organic phosphorus and increasing the availability of inorganic P by more than twofold. Our study suggest that, while decomposition processes in ombrotrophic bogs occur very slowly, rapid changes in the form and availability of phosphorus in vegetation and litter may occur as the result of forest fires on peat soils. Copyright © 2014 Elsevier Ltd. All rights reserved.

The ash in forest fire affected soils control the soil losses. Part 1. The pioneer research

NASA Astrophysics Data System (ADS)

Cerdà, Artemi; Pereira, Paulo

2013-04-01

After forest fires, the ash and the remaining vegetation cover on the soil surface are the main protection against erosion agents. The control ash exert on runoff generation mechanism was researched during the 90's (Cerdà, 1998a; 1998b). This pioneer research demonstrated that after forest fires there is a short period of time that runoff and surface wash by water is controlled by the high infiltration rates achieved by the soil, which were high due to the effect of ash acting as a mulch. The research of Cerdà (1998a; 1998b) also contributed to demonstrate that runoff was enhanced four month later upon the wash of the ash by the runoff, but also due to the removal of ash due to dissolution and water infiltration. As a consequence of the ephemeral ash cover the runoff and erosion reached the peak after the removal of the ash (usually four month), and for two years the soil erosion reached the peak (Cerdà, 1998a). Research developed during the last decade shown that the ash and the litter cover together contribute to reduce the soil losses after the forest fire (Cerdà and Doerr, 2008). The fate of the ash is related to the climatic conditions of the post-fire season, as intense thunderstorms erode the ash layer and low intensity rainfall contribute to a higher infiltration rate and the recovery of the vegetation. Another, key factor found during the last two decades that determine the fate of the ash and the soil and water losses is the impact of the fauna (Cerdà and Doerr, 2010). During the last decade new techniques were developed to study the impact of ash in the soil system, such as the one to monitor the ash changes by means of high spatial resolution photography (Pérez Cabello et al., 2012), and laboratory approaches that show the impact of ash as a key factor in the soil hydrology throughout the control they exert on the soil water repellency (Bodí et al., 2012). Laboratory approaches also shown that the fire severity is a key factor on the ash chemical composition (Pereira and Úbeda, 2010) and Pereira et al., 2012). Some of the new research challenges related to ash impact in the fire affected soils are related to the ash redistribution after the fire, the impact of ash in soil and water chemistry, the temporal changes of soil erosion, the control ash exert on vegetation recovery and the role to be played by ash in the best management of fire affected land. Those topics needs new ideas and new scientists such as Paulo Pereira show in the Part II of this abstract. Acknowledgements, Lithuanian Research Council. Project LITFIRE, Fire effects on Lithuanian soils and ecosystems (MIP-48/2011) and the research projects GL2008-02879/BTE and LEDDRA 243857. References Bodí, M., Mataix-Solera, J., Doerr, S., and Cerdà, A. 2011b. The wettability of ash from burned vegetation and its relationship to Mediterranean plant species type, burn severity and total organic carbon content. Geoderma, 160, 599-607. Cerdà, A. 1998a. Postfire dynamics of erosional processes under mediterranean climatic conditions. Z. Geomorphol., 42 (3) 373-398. Cerdà, A. 1998b. Changes in overland flow and infiltration after a rangeland fire in a Mediterranean scrubland. Hydrological Processes, 12, 1031-1042. Cerdà, A., and Doerr, S. H.2010. The effect of ant mounds on overland flow and soil erodibility following a wildfire in eastern Spain. Ecohydrology, 3, 392-401. Cerdà, A., and Doerr, S.H. 2008. The effect of ash and needle cover on surface runoff and erosion in the immediate post-fire period. Catena, 74, 256-263. Pereira, P., and Úbeda, X. 2010. Spatial distribution of heavy metals released from ashes after a wildfire, Journal of Environment Engineering and Landscape Management, 18, 13-22. Pereira, P., Ubeda, X., Martin, D.A. 2012. Fire severity effects on ash chemical composition and extractable elements. Geoderma, 191, 105 - 114. Pérez-Cabello, F., Cerdà, A., de la Riva, J., Echeverría, M.T., García-Martín, A., Ibarra, P., Lasanta, T., Montorio, R., Palacios, V. 2012. Micro-scale post-fire surface cover changes monitored using high spatial resolution photography in a semiarid environment: A useful tool in the study of post-fire soil erosion processes. Journal of Arid Environments, 76, 88-96.

Fire Effects on Microbial Enzyme Activities in Larch Forests of the Siberian Arctic

NASA Astrophysics Data System (ADS)

Ludwig, S.; Alexander, H. D.; Bulygina, E. B.; Mann, P. J.; Natali, S.

2012-12-01

Arctic forest ecosystems are warming at an accelerated rate relative to lower latitudes, with global implications for C cycling within these regions. As climate continues to warm and dry, wildfire frequency and severity are predicted to increase, creating a positive feedback to climate warming. Increased fire activity will also influence the microenvironment experienced by soil microbes in disturbed soils. Because soil microbes regulate carbon (C) and nitrogen (N) cycling between terrestrial ecosystems and the atmosphere, it is important to understand microbial response to fires, particularly in the understudied larch forests in the Siberian Arctic. In this project, we created experimental burn plots in a mature larch forest in the Kolyma River watershed of Northeastern Siberia. Plots were burned at several treatments: control (no burn), low, moderate, and severe. After, 1 and 8 d post-fire, we measured soil organic layer depth, soil organic matter (SOM) content, soil moisture, and CO2 flux from the plots. Additionally, we leached soils and measured dissolved organic carbon (DOC), total dissolved nitrogen (TDN), NH4, NO3, soluble reactive phosphorus (SRP), and chromophoric dissolved organic matter (CDOM). Furthermore, we measured extracellular activity of four enzymes involved in soil C and nutrient cycling (leucine aminopeptidase (LAP), β-glucosidase, phosphatase, and phenol oxidase). One day post-fire, LAP activity was similarly low in all treatments, but by 8 d post-fire, LAP activity was lower in burned plots compared to control plots, likely due to increased nitrogen content with increasing burn severity. Phosphatase activity decreased with burn severity 1 d post-fire, but after 8 d, moderate and severe burn plots exhibited increased phosphatase activity. Coupled with trends in LAP activity, this suggests a switch in nutrient limitation from N to phosphorus that is more pronounced with burn severity. β-glucosidase activity similarly decreased with burn severity 1 d post-fire, but by 8 d post-fire activity was the same in all treatments, indicating complete recovery of the microbial population. Phenol oxidase activity was low in all treatments 1 d post-fire, but by 8 d post-fire, severe plots had substantially increased phenol oxidase activity, likely due to microbial efforts to mitigate phenolic compound toxicity following severe fires. Both DOC and the slope ratio of CDOM absorbance increased with burn severity 1 d post-fire, indicating higher extractability of lighter molecular weight C from severe burns. These results imply that black C created from fires remains as a stable C pool while more labile C is mobilized with increasing burn severity. Our results suggest that the immediate effects of fire severity on microbial communities have the potential to change both nutrient use and the form and concentration of C being processed and mobilized from larch forest ecosystems. These findings highlight the importance of changing fire regimes on soil dynamics with implications for forest re-growth, soil-atmospheric feedbacks, and terrestrial inputs to aquatic ecosystems.

A Drought Index for Forest Fire Control

Treesearch

John J. Keetch; George M. Byram

1968-01-01

The moisture content of the upper soil, as well as that of the covering layer of duff, has an important effect on the fire suppression effort in forest and wildland areas. In certain forested areas of the United States, fires in deep duff fuels are of particular concern to the fire control manager. When these fuels are dry, fires burn deeply, dam-age is excessive, and...

Long-term impact of wildfire on soils exposed to different fire severities. A case study in Cadiretes Massif (NE Iberian Peninsula).

PubMed

Francos, Marcos; Úbeda, Xavier; Pereira, Paulo; Alcañiz, Meritxell

2018-02-15

Wildfires affect ecosystems depending on the fire regime. Long-term studies are needed to understand the ecological role played by fire, especially as regards its impact on soils. The aim of this study is to monitor the long-term effects (18years) of a wildfire on soil properties in two areas affected by low and high fire severity regimes. The properties studied were total nitrogen (TN), total carbon (TC), C/N ratio, soil organic matter (SOM) and extractable calcium (Ca), magnesium (Mg), sodium (Na) and potassium (K). The study was carried out in three phases: short- (immediately after the wildfire), medium- (seven years after the wildfire) and long-term (18years after the wildfire). The results showed that in both fire regimes TN decreased with time, TC and SOM were significantly lower in the burned plots than they were in the control in the medium- and long-terms. C/N ratio was significantly lower at short-term in low wildfire severity area. Extractable Ca and Mg were significantly higher in control plot than in the burned plots in the medium-term. In the long-term, extractable Ca and Mg were significantly lower in the area exposed to a high severity burning. No differences were identified in the case of extractable Na between plots on any of the sampling dates, while extractable K was significantly higher in the plot exposed to low wildfire than it was in the control. Some restoration measures may be required after the wildfire, especially in areas affected by high severity burning, to avoid the long-term impacts on the essential soil nutrients of TC, SOM, extractable Ca and Mg. This long-term nutrient depletion is attributable to vegetation removal, erosion, leaching and post-fire vegetation consumption. Soils clearly need more time to recover from wildfire disturbance, especially in areas affected by high severity fire regimes. Copyright © 2017 Elsevier B.V. All rights reserved.

Interactions between soil thermal and hydrological dynamics in the response of Alaska ecosystems to fire disturbance

USGS Publications Warehouse

Yi, Shuhua; McGuire, A. David; Harden, Jennifer; Kasischke, Eric; Manies, Kristen L.; Hinzman, Larry; Liljedahl, Anna K.; Randerson, J.; Liu, Heping; Romanovsky, Vladimir E.; Marchenko, Sergey S.; Kim, Yongwon

2009-01-01

Soil temperature and moisture are important factors that control many ecosystem processes. However, interactions between soil thermal and hydrological processes are not adequately understood in cold regions, where the frozen soil, fire disturbance, and soil drainage play important roles in controlling interactions among these processes. These interactions were investigated with a new ecosystem model framework, the dynamic organic soil version of the Terrestrial Ecosystem Model, that incorporates an efficient and stable numerical scheme for simulating soil thermal and hydrological dynamics within soil profiles that contain a live moss horizon, fibrous and amorphous organic horizons, and mineral soil horizons. The performance of the model was evaluated for a tundra burn site that had both preburn and postburn measurements, two black spruce fire chronosequences (representing space-for-time substitutions in well and intermediately drained conditions), and a poorly drained black spruce site. Although space-for-time substitutions present challenges in model-data comparison, the model demonstrates substantial ability in simulating the dynamics of evapotranspiration, soil temperature, active layer depth, soil moisture, and water table depth in response to both climate variability and fire disturbance. Several differences between model simulations and field measurements identified key challenges for evaluating/improving model performance that include (1) proper representation of discrepancies between air temperature and ground surface temperature; (2) minimization of precipitation biases in the driving data sets; (3) improvement of the measurement accuracy of soil moisture in surface organic horizons; and (4) proper specification of organic horizon depth/properties, and soil thermal conductivity.

Fire Effects on Soil and Dissolved Organic Matter in a Southern Appalachian Hardwood Forest: Movement of Fire-Altered Organic Matter Across the Terrestrial-Aquatic Interface Following the Great Smoky Mountains National Park Fire of 2016

NASA Astrophysics Data System (ADS)

Matosziuk, L.; Gallo, A.; Hatten, J. A.; Heckman, K. A.; Nave, L. E.; Sanclements, M.; Strahm, B. D.; Weiglein, T.

2017-12-01

Wildfire can dramatically affect the quantity and quality of soil organic matter (SOM), producing thermally altered organic material such as pyrogenic carbon (PyC) and polyaromatic hydrocarbons (PAHs). The movement of this thermally altered material through terrestrial and aquatic ecosystems can differ from that of unburned SOM, with far-reaching consequences for soil carbon cycling and water quality. Unfortunately, due to the rapid ecological changes following fire and the lack of robust pre-fire controls, the cycling of fire-altered carbon is still poorly understood. In December 2016, the Chimney Tops 2 fire in Great Smoky Mountains National Park burned over co-located terrestrial and aquatic NEON sites. We have leveraged the wealth of pre-fire data at these sites (chemical, physical, and microbial characterization of soils, continuous measurements of both soil and stream samples, and five soil cores up to 110 cm in depth) to conduct a thorough study of the movement of fire-altered organic matter through terrestrial and aquatic ecosystems. Stream samples have been collected weekly beginning 5 weeks post-fire. Grab samples of soil were taken at discrete time points in the first two months after the fire. Eight weeks post-fire, a second set of cores was taken and resin lysimeters installed at three different depths. A third set of cores and grab samples will be taken 8-12 months after the fire. In addition to routine soil characterization techniques, solid samples from cores and grab samples at all time points will be analyzed for PyC and PAHs. To determine the effect of fire on dissolved organic matter (DOM), hot water extracts of these soil samples, as well as the stream samples and lysimeter samples, will also be analyzed for PyC and PAHs. Selected samples will be analyzed by 1D- and 2D-NMR to further characterize the chemical composition of DOM. This extensive investigation of the quantity and quality of fire-altered organic material at discrete time points will provide insight into the production and cycling of thermally-altered SOM and DOM. We hypothesize that PyC will be an important source of SOM to surface mineral soil horizons, and that the quantity of DOM will increase after fire, providing a rapid pulse of C to deep soils and aquatic systems.

Soil nitrogen mineralization and enzymatic activities in fire and fire surrogate treatments in California

Treesearch

J. R. Miesel; R. E. J. Boerner; C. N. Skinner

2011-01-01

Forest thinning and prescribed fire are management strategies used to reduce hazardous fuel loads and catastrophic wildfires in western mixed-conifer forests. We evaluated effects of thinning (Thin) and prescribed fire (Burn), alone and in combination (Thin+Burn), on N transformations and microbial enzyme activities relative to an untreated control (Control) at 1 and 3...

Post-wildfire erosion in mountainous terrain leads to rapid and major redistribution of soil organic carbon

NASA Astrophysics Data System (ADS)

Abney, Rebecca B.; Sanderman, Jonathan; Johnson, Dale; Fogel, Marilyn L.; Berhe, Asmeret Asefaw

2017-11-01

Catchments impacted by wildfire typically experience elevated rates of post-fire erosion and formation and deposition of pyrogenic carbon (PyC). To better understand the role of erosion in post-fire soil carbon dynamics, we determined distribution of soil organic carbon in different chemical fractions before and after the Gondola fire in South Lake Tahoe, CA. We analyzed soil samples from eroding and depositional landform positions in control and burned plots pre- and post-wildfire (in 2002, 2003, and 10-years post-fire in 2013). We determined elemental concentrations, stable isotope compositions, and biochemical composition of organic matter (OM) using mid-infrared (MIR) spectroscopy for all of the samples. A subset of samples was analyzed by 13C cross polarization magic angle spinning nuclear magnetic resonance spectroscopy (CPMAS 13C-NMR). We combined the MIR and CPMAS 13C-NMR data in the Soil Carbon Research Program partial least squares regression model to predict distribution of soil carbon into three different fractions: 1) particulate, humic, and resistant organic matter fractions representing relatively fresh larger pieces of OM, 2) fine, decomposed OM, and 3) pyrogenic C, respectively. Samples from the post-fire eroding landform position showed no major difference in soil organic carbon (SOC) fractions one year post-fire. The depositional samples, however, had increased concentrations of all SOC fractions, particularly the fraction that resembles PyC, one year post-fire (2002), which had a mean of 160 g/kg compared with burned hillslope soils, which had 84 g/kg. The increase in all SOC fractions in the post-fire depositional landform position one year post-fire indicates significant lateral mobilization of the eroded PyC. In addition, our NMR analyses revealed a post-fire increase in both the aryl and O-aryl carbon compounds in the soils from the depositional landform position, indicating increases in soil PyC concentrations post-fire. After 10 years, the C concentration from all three fractions declined in the depositional landform position to below pre-fire levels likely due to further erosion or elevated rates of decomposition. Thus, we found, at this site, that both fire and erosion exert significant influence on the distribution of PyC throughout a landscape and its long-term fate in the soil system.

How clear-cutting affects fire severity and soil properties in a Mediterranean ecosystem.

PubMed

Francos, Marcos; Pereira, Paulo; Mataix-Solera, Jorge; Arcenegui, Victoria; Alcañiz, Meritxell; Úbeda, Xavier

2018-01-15

Forest management practices in Mediterranean ecosystems are frequently employed to reduce both the risk and severity of wildfires. However, these pre-fire treatments may influence the effects of wildfire events on soil properties. The aim of this study is to examine the short-term effects of a wildfire that broke out in 2015 on the soil properties of three sites: two exposed to management practices in different years - 2005 (site M05B) and 2015 (site M15B) - and one that did not undergo any management (NMB) and to compare their properties with those recorded in a plot (Control) unaffected by the 2015 wildfire. We analyzed aggregate stability (AS), soil organic matter (SOM) content, total nitrogen (TN), carbon/nitrogen ratio (C/N), inorganic carbon (IC), pH, electrical conductivity (EC), extractable calcium (Ca), magnesium (Mg), sodium (Na), and potassium (K), microbial biomass carbon (C mic ) and basal soil respiration (BSR). In the managed plots, a clear-cutting operation was conducted, whereby part of the vegetation was cut and left covering the soil surface. The AS values recorded at the Control site were significantly higher than those recorded at M05B, whereas the TN and SOM values at NMB were significantly higher than those recorded at M05B. IC was significantly higher at M05B than at the other plots. There were no significant differences in C/N ratio between the analyzed sites. Soil pH at M05B was significantly higher than the value recorded at the Control plot. Extractable Ca was significantly higher at NMB than at both M05B and the Control, while extractable Mg was significantly lower at M05B than at NMB. Extractable K was significantly lower at the Control than at the three fire-affected plots. C mic was significantly higher at NMB than at the Control. BSR, BSR/C and BSR/C mic values at the fire-affected sites were significantly lower than those recorded at the Control. No significant differences were identified in C mic /C. Overall, a comparison of the pre-fire treatments showed that NMB was the practice that had the least negative effects on the soil properties studied, followed by M15B, and that fire severity was highest at M05B due to the accumulation of dead plant fuel. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fire effects in northeastern forests: red pine.

Treesearch

Cary Rouse

1988-01-01

Fire and red pine are closely associated. Fires can provide red pine with the mineral soil and freedom from competition it needs to become well established. Fire can also be used to control pests, increase tree growth, enhance aesthetics, and improve wildlife habitat.

Restoration of a Mediterranean forest after a fire: bioremediation and rhizoremediation field-scale trial

PubMed Central

Pizarro-Tobías, Paloma; Fernández, Matilde; Niqui, José Luis; Solano, Jennifer; Duque, Estrella; Ramos, Juan-Luis; Roca, Amalia

2015-01-01

Forest fires pose a serious threat to countries in the Mediterranean basin, often razing large areas of land each year. After fires, soils are more likely to erode and resilience is inhibited in part by the toxic aromatic hydrocarbons produced during the combustion of cellulose and lignins. In this study, we explored the use of bioremediation and rhizoremediation techniques for soil restoration in a field-scale trial in a protected Mediterranean ecosystem after a controlled fire. Our bioremediation strategy combined the use of Pseudomonas putida strains, indigenous culturable microbes and annual grasses. After 8 months of monitoring soil quality parameters, including the removal of monoaromatic and polycyclic aromatic hydrocarbons as well as vegetation cover, we found that the site had returned to pre-fire status. Microbial population analysis revealed that fires induced changes in the indigenous microbiota and that rhizoremediation favours the recovery of soil microbiota in time. The results obtained in this study indicate that the rhizoremediation strategy could be presented as a viable and cost-effective alternative for the treatment of ecosystems affected by fires. PMID:25079309

Impact of Wildfire on Microbial Biomass in Critical Zone Observatory

NASA Astrophysics Data System (ADS)

Murphy, M. A.; Fairbanks, D.; Chorover, J.; Gallery, R. E.; Rich, V. I.

2014-12-01

The recovery of the critical zone following disturbances such as wildfire is not fully understood. Wildfires have increased in size and intensity in western US forests in recent years and these fires influence soil microbial communities, both in composition and overall biomass. Studies have typically shown a 50% post-fire decline in overall microbial biomass (µg per g soil) that can persist for years. There is however, some variability in the severity of biomass decline, and its relationship with burn severity and landscape position have not yet been studied. Since microbial biomass has a cascade of impacts in soil systems, from helping control the rate and diversity the biogeochemical processes occurring, to promoting soil fertility, to impacting the nature and structure of soil carbon (C), fire's lasting impact on it is one mechanistic determinant of the overall post-fire recovery of impacted ecosystems. Additionally, microbial biomass measurements hold potential for testing and incorporation into land surface models (NoahMP, CLM, etc.) in order to improve estimates of long-term effects of climate change and disturbances such as fire on the C cycle. In order to refine our understanding of the impact of fire on microbial biomass and then relate that to biogeochemical processes and ecosystem recovery, we used chloroform fumigation extraction to quantify total microbial biomass C (Cmic ). One year after the June 2013 Thompson Ridge fire in the Jemez River Basin Critical Zone Observatory, we are measuring the Cmic of 22 sites across a gradient of burn severities and 4 control unburned sites, from six depth intervals at each site (0-2, 2-5, 5-10, 10-20, 20-30, and 30-40 cm). We hypothesize that the decrease in microbial biomass in burned sites relative to control sites will correlate with changes in soil biogeochemistry related to burn severity; and that the extent of the impact on biomass will be inversely related to depth in the soil column. Additionally, as the project progresses, we will relate microbial biomass to microbial functional assays as proxy for biogeochemical activity, and test variation by landscape position and aspect.

Wild fire impact on copper, zinc, lead and cadmium distribution in soil and relation with abundance in selected plants of Lamiaceae family from Vidlic Mountain (Serbia).

PubMed

Stankov Jovanovic, V P; Ilic, M D; Markovic, M S; Mitic, V D; Nikolic Mandic, S D; Stojanovic, G S

2011-09-01

Fire has been considered as an improving factor in soil quality, but only if it is controlled. Severe wild fire occurred in the summer 2007 on the Vidlic Mountain (Serbia) overspreading a huge area of meadows and forests. Main soil characteristics and content of heavy metals (Cu, Pb, Cd, Zn) in different fractions obtained after sequential extraction of soil from post-fire areas and from fire non disturbed areas were studied. In four plant species of Lamiaceae family (Ajuga genevensis L., Lamium galeobdolon (L.) L., Teucrium chamaedrys L., Acinos alpinus (L.) Moench.), that grow in typical habitats of the mountain, distribution of heavy metals in aerial parts and roots was investigated too. For all samples from post-fire area cation exchange capacity and soil organic matter content are increased while rH is decreased. Fire caused slightly increased bioavailability of the observed metals but more significant rise happened in metal amounts bound to oxides and organics. The plants showed variable behavior. T. chamaedrys collected on the post-fire area contained elevated concentrations of all analyzed metals. A. alpinus showed higher phytoaccumulation for Zn and Cd, while the other two plant species for Pb and Cd in the post-fire areas. Copyright © 2011 Elsevier Ltd. All rights reserved.

Characterization of the humic substances isolated from postfire soils of scotch pine forest in Togljatty city, Samara region by the 13C-NMR spectroscopy

NASA Astrophysics Data System (ADS)

Maksimova, Ekaterina; Abakumov, Evgeny

2016-04-01

Postpyrogenic soil dynamics is an informative tool for studying of soil elementary processes in extreme temperature conditions and for predicting of short time environmental changes in conditions of catastrophic landscape changes. Soil organic matter (SOM) system evolution is the most rapid process of postpyrogenic soil development. In this relation the evaluation of humus accumulation rates and humification trend were conducted with use of the classical chemical and modern spectroscopy methods. Soil restoration after spontaneous forest fires near Togljatty city (Samara region, Russia) was abandoned in 2010, and further monitoring over the next four years was organized to evaluate the speed of biogenic processes and humus accumulation dynamics. Three key soil plots were studied for estimating SOM quality changes under the forest fire effect: surface forest fire, crown forest fire and control. Total carbon and nitrogen content as well as Cha/Cfa ratios (content of humic acids/ content of fulvic acids), were estimated to assess the dynamics of soil restoration. Humic acid powders were extracted and analyzed by elemental composition and 13C-NMR spectroscopy to assess changes in humic substance structure and composition. The data obtained indicate that burning of a forest floor and sod (humic) horizon led to humus losses and decreases in total carbon stocks. As a result of the fires, the content of humic acids in the pyrogenic horizon increased, leading alterations of humus type. Greater increases in the degree of organic matter humification were observed for surface fires than crown fires. It was shown that the humus molecular composition was substantially affected by the wildfires. The data show an increase in aromaticity, a loss of oxygen-containing groups and dehydrogenation of humic acids. Humic acids in the soils of the control plots and after wildfires were significantly different, especially in the ratios of hydrogen, oxygen and carbon. The increase in the degree of humic acid aromatization was confirmed by the hydrogen/carbon ratio. Investigation of the humic acids' molecular structure by 13C-NMR showed a relative increase in aromatic compounds and decrease in aliphatic ones. In general, crown and surface fires plots are not very different in terms of 13C-NMR spectra of humic acids, however humic acids of control plot have essential differences from pyrogenic ones. This study was a contribution to the Russian foundation for basic research, project for young scientists No.14-04-32132 and 15-34-20844.

Effects of salvage logging on soil properties and vegetation recovery in a fire-affected Mediterranean forest: A two year monitoring research.

PubMed

García-Orenes, F; Arcenegui, V; Chrenková, K; Mataix-Solera, J; Moltó, J; Jara-Navarro, A B; Torres, M P

2017-05-15

Post-fire management can have an additional impact on the ecosystem; in some cases, even more severe than the fire. Salvage logging (SL) is a common practice in most fire-affected areas. The management of burnt wood can determine microclimatic conditions and seriously affect soil properties. In some cases, the way of doing it, using heavy machinery, and the vulnerability of soils to erosion and degradation can make this management potentially aggressive to soil. Research was done in "Sierra de Mariola Natural Park" (E Spain). A forest fire (>500ha) occurred in July 2012. In February 2013, SL treatment was applied in a part of the affected forest. Plots for monitoring this effect were installed in this area and in a similar nearby area where no treatment was done, used as control (C). Soil samplings were done immediately after treatment and every 6months during two years. Some soil properties were analysed, including organic matter (OM) content, nitrogen (N) available phosphorous (P) basal soil respiration (BSR), microbial biomass carbon (C mic ), bulk density (BD), water repellency (WR), aggregate stability (AS) and field capacity (FC). SL treatment caused an increase in BD, a decrease of AS, FC, OM and N. In the control area, in general the soil properties remained constant across the 2years of monitoring, and the microbial parameters (BSR and C mic ), initially affected by the fire, recovered faster in C than in the SL area. Plant recovery also showed some differences between treatments. No significant differences were observed in the number of plant species recorded (richness) comparing C versus SL plots, but the number of individuals of each species (evenness) was significantly higher in C plots. In conclusion, we can affirm that for the conditions of this study case, SL had a negative effect on the soil-plant system. Copyright © 2017 Elsevier B.V. All rights reserved.

Predicting fire impact from plant traits?

NASA Astrophysics Data System (ADS)

Stoof, Cathelijne; Ottink, Roos; Zylstra, Philip; Cornelissen, Hans; Fernandes, Paulo

2017-04-01

Fire can considerably increase the landscape's vulnerability to flooding and erosion, which is in part caused by fire-induced soil heating, vegetation removal and resulting hydrological changes. While the magnitude of these fire effects and ecosystem responses is frequently studied, there is still little attention for the fundamental mechanisms that drive these changes. One example is on the effect of plants: while it is known that plants can alter the fire environment, there is a major knowledge gap regarding the fundamental mechanisms by which vegetation mediates fire impact on soil and hydrology. Essential to identifying these mechanisms is consideration of the effects of vegetation on flammability and fire behaviour, which are studied both in ecology and traditional fire science. Here we discuss the challenges of integrating these very distinct fields and the potential benefits of this integration for improved understanding of fire effects on soil and hydrology. We furthermore present results of a study in which we assessed the spatial drivers controlling the proportion of live and dead fuel in a natural park in northern Portugal, and evaluated the impacts on the spatial variability of fire behaviour and potential soil heating using BehavePlus modeling. Better understanding of the role of (spatial variability in) plant traits on fire impact can facilitate the development of risk maps to ultimately help predict and mitigate fire risk and impact across landscapes.

Fire Effects on Microbial Dynamics and C, N, and P Cycling in Larch Forests of the Siberian Arctic

NASA Astrophysics Data System (ADS)

Ludwig, S.; Alexander, H. D.; Mann, P. J.; Natali, S.; Schade, J. D.

2013-12-01

Arctic forest ecosystems are warming at an accelerated rate relative to lower latitudes, with global implications for C cycling within these regions. As climate continues to warm and dry, wildfire frequency and severity are predicted to increase, creating a positive feedback to climate warming. Because soil microbes regulate carbon (C) and nitrogen (N) cycling between terrestrial ecosystems and the atmosphere, it is important to understand microbial response to fires, particularly in the understudied larch forests in the Siberian Arctic. In this project, we created experimental burn plots in a mature larch forest in the Kolyma River watershed of Northeastern Siberia. Plots were burned at several treatments: control (no burn), low, moderate, and severe. After 1 day, 8 days and 1 year post-fire, we measured CO2 flux from the plots, and measured dissolved organic carbon (DOC), total dissolved nitrogen (TDN), NH4, NO3, PO4, and chromophoric dissolved organic matter (CDOM) from soil leachates. Furthermore, we measured extracellular activity of four enzymes involved in soil C and nutrient cycling (leucine aminopeptidase (LAP), β-glucosidase, phosphatase, and phenol oxidase). Both 1 day and 8 days post-fire DOC, TDN, NH4, and PO4 all increased with burn severity, but by 1 year they were similar to control plots. The aromaticity and molecular weight of DOM decreased with fire severity. One day post-fire we observed a spike in phenol oxidase activity in the severe burns only, and a decline in β-glucosidase and phosphatase activity. By 8 days post-fire all enzyme activities were at the level of the control plots. 1 year post-fire LAP, β-glucosidase, and phosphatase all decreased with fire severity, parallel to a decrease in CO2 flux by fire severity. Ratios of enzymatic activity 1 year post-fire reflect a switch of resource allocation from P acquiring to N acquiring activities in more severe fires. Our results show an immediate microbial response to the short-term effects of fire severity that reflects both a change in nutrient use and the form and concentration of C being processed, and a response to long-term effects of fire severity that show further changes in nutrient use and overall decreased microbial activity. These findings highlight the importance of changing fire regimes on soil dynamics with implications for forest re-growth, soil-atmospheric feedbacks, and terrestrial inputs to aquatic ecosystems.

Spatio-temporal effects of low severity grassland fire on soil colour

NASA Astrophysics Data System (ADS)

Pereira, Paulo; Cerdà, Artemi; Bolutiene, Violeta; Pranskevicius, Mantas; Úbeda, Xavier; Jordán, Antonio; Zavala, Lorena; Mataix-Solera, Jorge

2013-04-01

Fire changes soil properties directly, through temperature, or indirectly with ash deposition and the temporal elimination of vegetal cover. Both influences change soil colour and soil properties. The degree of changes depends on fire severity that has important implications on soil organic matter, texture, mineralogy and hydrological properties and type of ash produced. The ash colour is different according to the temperature of combustion and burned specie and this property will have implications on soil colour. In addition, ash properties have a strong spatial variability. The aim of this work is to study the spatio-temporal effects of a low severity grassland fire on soil colour occurred in Lithuania, near Vilnius city (54° 42' N, 25° 08' E, 158 m.a.s.l.). After the fire it was designed a plot of 20x20m in a burned and unburned flat area. Soil colour was analysed immediately after the fire, and 2, 5, 7 and 9 months after the fire. In each sampling 25 soil samples were collected, carried out to the laboratory, dried at room temperature (20-24° C) and sieved with the <2mm mesh. Soil colour was observed with the Munsell colour chart and the soil chroma value (CV) was observed. Since data did not respected the Gaussian distribution a neperian logarithmic (ln) transformation was applied. Differences among time and between plots were observed with the repeated measures ANOVA test, followed by a Tukey HSD test. Differences were significant at a p<0.05. The spatial variability (SV) was assessed with the coefficient of variation using non transformed data. The results showed differences among time at a p<0.001, treatment at a p<0.01 and time x treatment at a p<0.01. This means that fire during the first 9 months changed significantly soil colour. The CV of the burned plot was lower than the control plot (darker colour), that is attributed to the deposition of charred material and charcoal. This ash produced in this fire was mainly black coloured. With the time the soil of the burned plot became lighter, due the movement of charred material and charcoal in depth through soil profile. After the fire SV was higher in the burned plot (13.27%) than in the unburned plot (7.95%). This major variability might be attributed to ash influence, since this fire did nit had direct effects on soil. Despite the reduced CV, some patches burned at higher severity, and ash was dark and light grey and this might had influences on soil colour SV. In the following measurements SV was very similar, but always slightly higher in the control plot than in the burned plot. Two months, unburned 15.52% and burned, 14.70%. Five months, unburned, 14.78% and burned 14.42%, Seven months, unburned, 15.15% and burned, 14.67%. Nine months, unburned, 18.96% and burned 17.84%. After the fire ash can be (re)distributed uncountable times. In the immediate period after the fire, finner ash produced at higher severities is easily transported by wind and can remix (Pereira et al., 2013a, Pereira et al., 2013b) and change soil colour. In this fire, vegetation recovered very fast, thus this process might occurred only in the first weeks after the fire (Pereira et al., 2013c). Since vegetation recovered fast, soil colour SV depended on carbon and charred material movement in depth soil profile. Further studies are needed on the soil colour evolution after the fire, since can be an indicator of soil properties such as temperature reached with implications in other soil properties. Acknowledgements The authors appreciated the support of the project "Litfire", Fire effects in Lithuanian soils and ecosystems (MIP-048/2011) funded by the Lithuanian Research Council, Spanish Ministry of Science and Innovation for funding through the HYDFIRE project CGL2010-21670-C02-01, FUEGORED (Spanish Network of Forest Fire Effects on Soils http://grupo.us.es/fuegored/) and to Comissionat per a Universitats i Recerca del DIUE de la Generalitat de Catalunya. References Pereira, P. Cerdà, A., Úbeda, X., Mataix-Solera, J. Arcenegui, V., Zavala, L. (2013a) Modelling the impacts of wildfire on ash thickness in a short-term period, Land Degradation and Development (In press) DOI: 10.1002/ldr.2195 Pereira, P., Cerdà, A., Úbeda, X., Mataix-Solera, J., Martin, D.A., Jordan, A. Burguet, M. (2013b) Effects of fire on ash thickness in a Lithuanian grassland and short-term spatio-temporal changes. Solid Earth Discussions, 4 (1), 1545-1584. doi:10.5194/sed-4-1-2012 Pereira, P., Pranskevicius, M., Cepanko, V., Vaitkute, D., Pundyte, N., Ubeda, X., Mataix-Soler, J., Cerda, A., Martin, D.A. (2013c) Short time vegetation recovers after a spring grassland fire in Lithuania. Temporal and slope position effect, Flamma, 4(1), 13-17.

Immediate changes in topsoil chemical properties after controlled shrubland burning in the Central Pyrenees

NASA Astrophysics Data System (ADS)

Zufiaurre-Galarza, Raquel; Fernández Campos, Marta; Badía-Villas, David; María Armas-Herrera, Cecilia; Martí-Dalmau, Clara; Girona-García, Antonio

2016-04-01

Prescribed fire has recently been adopted as an encroachment-fighting strategy in the Central Pyrenees. Despite relatively large information on wildfire impacts on soil, there is little information on prescribed fire effects, especially in mountain ecosystems (Shakesby et al, 2015). Fire effects are noticeable in the topsoil, particularly in relation to soil organic matter and nutrient contents and quality (Alexis et al, 2012). These components change with time after fire and at the scale of the upper few centimetres of mineral soil (Badía et al, 2014). The aim of this study is to evaluate the immediate effects of prescribed shrubland burning on soil's nutrients and organic matter content to detect changes at cm-scale, trying to differentiate the heat shock from the subsequent incorporation of ash and charcoal. The study area, densely covered with spiny broom (Echinospartum horridum), is located in Tella (Central Pyrenees, NE Spain) at 1900 meters above sea level. Three sites were sampled before burning and immediately after burning just in its adjacent side. The soils belong to the WRB unit Leptic Eutric Cambisol, Soil samples were collected separating carefully the organic layers (litter in unburned soils and ashes and fire-altered organic residues in burned soils) and the mineral horizon at 0-1, 1-2 and 2-3 cm depths. Soil samples were air-dried and sieved to 2 mm. Soil organic C (by the wet oxidation method), total N (Kjeldahl method), water-soluble ions (Ca2+, Mg2+, Na+, K+, SO4=, NO3- and NH4+), exchangeable ions (Ca2+, Mg2+, K+, Na+, Fe3+ and Mn2+), total and available P, pH (1:5) and the electrical conductivity (in a 1:10 soil-to-water ratio) were measured. Immediately after the controlled fire, soil organic carbon content on burned topsoil decreases significantly within 0-3 cm of soil depth studied while total N decrease was not significant. Moreover, only a slight increase of the electrical conductivity, water-soluble ions and exchangeable ions was observed on burned topsoil. These changes detected immediately after fire (SOC decrease and slight nutrients increase) are related to the heat released during the severe intensity of prescribed burning. Few changes in nutrients are yet observed due to the negligible incorporation of ashes into the soil, still remaining on the surface. In the medium term, it can be expected its partial incorporation into the soil and, also, ash and soil losses depending on the rain intensity and the amount of time in which the soil is kept bare. REFERENCES Alexis et al. (2012). Evolution of soil organic matter after prescribed fire: A 20-year chronosequence. Geoderma 189-190: 98-107. Badía et al. (2014). Wildfire effects on nutrients and organic carbon of a Rendzic Phaeozem in NE Spain: Changes at cm-scale topsoil. Catena 113: 267-275. Shakesby et al. (2015). Impacts of prescribed fire on soil loss and soil quality: An assessment based on an experimentally-burned catchment in central Portugal. Catena 128: 278-293

Fire Events and Soil Thermometry: The Applications of Clay Chemistry for Tracing Temperature Changes in Soils and Sediments Below Surface Fires

NASA Astrophysics Data System (ADS)

Watson, E.; Werts, S. P.; Gelabert, M.

2016-12-01

Fires in the natural environment affect the physical, chemical, and biological properties of soils. However, fires may also alter the mineralogy of the geologic material in which it comes in contact. Previous experiments on high temperature alteration of clays indicate that dehydration, oxidation, and hydroxylation in clay minerals can occur progressively in that order at increasing temperatures up to 500°C. It is also well known that wildfire events can heat soils to these temperature ranges several centimeters deep. In this experiment, alterations in clay chemistry were used as a tool to investigate fire intensity along with the changing morphology of clay minerals. For data collection, small camp fires were set in York County, SC and temperatures were recorded using a datalogger system to 5 cm deep during the fire event. Control samples were taken adjacent to the fires to compare the changing morphology of the minerals when heated. Powder x-ray diffraction and scanning electron microscopy were used to identify the clay mineralogy. The clay from soil samples was identified as hydrous kaolinite, anhydrous kaolinite, and varying types of goethite. To observe the dehydration, oxidation, and hydroxylation of clay minerals, scanning electron microscopy with emission dispersive spectroscopy was used to identify the O/cation ratios present, which would indicate changes in the oxidation state of the clay minerals. By mapping the changes in O/cation ratios with temperature in silicates, we are able to trace the temperature of the sediments during fire events. This research suggests it may be possible to utilize these geochemical trends to aid in soil and sediment temperature investigations in both archeological and modern soil and surface process investigations.

Stocking rate impact on soil water repellency and erodibility of burnt lands

NASA Astrophysics Data System (ADS)

Stavi, Ilan; Zaady, Eli

2017-04-01

Wildfires and prescribed burnings are common, modifying the functioning of geo-ecosystems. Such fires have been extensively studied, and reported to considerably affect soil properties. Yet, understanding of the impact of livestock grazing, or more precisely, trampling, in fire-affected lands is limited. The objective of this study was to assess the impact of livestock trampling (hoof action) on the functioning of burnt vs. non-burnt lands. This was studied by focusing on the effects on wettability and related properties of solid soil, as well as on the quantity of unconsolidated material (detached matter) lying on the solid ground surface. The study was implemented in the semi-arid northern Negev of Israel, in lands which experienced a one cycle of (unintended) low- to moderate-fire severity. The study was conducted by allowing livestock to access plots under high, medium, and low stocking rates. Also, livestock exclusion plots were assigned as a control treatment. Soil wettability was studied by water drop penetration time (WDPT) and critical surface tension (CST) tests. Results show that fire slightly decreased the soil wettability. However, WDPT was negatively related to the stocking rate, and CST was 13% smaller in the control plots than in the livestock-presence treatments. Also, the results show that following burning, the resistance of soil to shear decreased by 70%. Mass of unconsolidated material was similar in the control plots of the burnt and non-burnt plots. At the same time, it was three-, eight-, and nine- fold greater in the plots of the burnt × low, burnt × medium, and burnt × high stocking rates, respectively, than in the corresponding non-burnt ones. This study shows that livestock trampling in low- to moderate-intensity fire-affected lands increases the shearing of the ground surface layer. On the one hand, this increases soil wettability. On the other hand, this impact considerably increases risks of on-site soil erosion and land degradation, and off-site environmental pollution.

Polyacrylamide application versus forest residue mulching for reducing post-fire runoff and soil erosion.

PubMed

Prats, Sergio Alegre; Martins, Martinho António Dos Santos; Malvar, Maruxa Cortizo; Ben-Hur, Meni; Keizer, Jan Jacob

2014-01-15

For several years now, forest fires have been known to increase overland flow and soil erosion. However, mitigation of these effects has been little studied, especially outside the USA. This study aimed to quantify the effectiveness of two so-called emergency treatments to reduce post-fire runoff and soil losses at the microplot scale in a eucalyptus plantation in north-central Portugal. The treatments involved the application of chopped eucalyptus bark mulch at a rate of 10-12 Mg ha(-1), and surface application of a dry, granular, anionic polyacrylamide (PAM) at a rate of 50 kg ha(-1). During the first year after a wildfire in 2010, 1419 mm of rainfall produced, on average, 785 mm of overland flow in the untreated plots and 8.4 Mg ha(-1) of soil losses. Mulching reduced these two figures significantly, by an average 52 and 93%, respectively. In contrast, the PAM-treated plots did not differ from the control plots, despite slightly lower runoff but higher soil erosion figures. When compared to the control plots, mean key factors for runoff and soil erosion were different in the case of the mulched but not the PAM plots. Notably, the plots on the lower half of the slope registered bigger runoff and erosion figures than those on the upper half of the slope. This could be explained by differences in fire intensity and, ultimately, in pre-fire standing biomass. © 2013 Elsevier B.V. All rights reserved.

Soil microbial abundance, activity and diversity response in two different altitude-adapted plant communities affected by wildfire in Sierra Nevada National Park (Granada, Spain)

NASA Astrophysics Data System (ADS)

Bárcenas-Moreno, Gema; Zavala, Lorena; Jordan, Antonio; Bååth, Erland; Mataix-Beneyto, Jorge

2013-04-01

Plant communities can play an important role in fire severity and post-fire ecosystem recovery due to their role as combustible and different plant-soil microorganisms interactions. Possible differences induced by plant and microorganisms response after fire could affect the general ecosystem short and long-term response and its sustainability. The main objective of this work was the evaluation of the effect of wildfire on soil microbial abundance, activity and diversity in two different plant communities associated to different altitudes in Sierra Nevada National Park (Granada, Spain). Samples were collected in two areas located on the Sierra Nevada Mountain between 1700 and 2000 m above sea level which were affected by a large wildfire in 2005. Two samplings were carried out 8 and 20 months after fire and samples were collected in both burned and unburned (control) zones in each plant community area. Area A is located at 1700m and it is formed by Quercus rotundifolia forest while area B is located at 2000 m altitude and is composed of alpine vegetation formed by creeping bearing shrubs. Microbial biomass measured by Fumigation-Extraction method followed the same trend in both areas showing slight and no significant differences between burned and unburned area during the study period while viable and cultivable bacteria abundance were markedly higher in fire affected samples than in the control ones in both samplings. Viable and cultivable filamentous fungi had different behavior depending of plant vegetation community studied showing no differences between burned and unburned area in area A while was significantly higher in burned samples than in the control ones in area B. Microbial activity monitoring with soil microbial respiration appears to had been affected immediately after fire since microbial respiration was lower in burned samples from area A than in unburned one only 8 months after fire and no significant differences were observed between burned and unburned samples in area B. Soil microbial community composition studied by Principal Component Analyses (PCA) of the PLFA pattern revealed both fire and seasonal effects. General overview of the results could lead to think in a slight negative or even positive effect of fire on soil microbial parameters studied, mainly in zone B. Nevertheless if we calculate the ratio between C-biomass and organic-C we find lower ratio in fire-affected samples than in the control ones in both areas, showing the most marked effect on area B which remain with this tendency 20 months after fire. Acknowledgements: This research was supported by the CICYT co-financed FEDER project CGL2006-11107-C02-01/BOS. We are grateful for the Sierra Nevada National Park support during the study.

Relationship between fire temperature and changes in chemical soil properties: a conceptual model of nutrient release

NASA Astrophysics Data System (ADS)

Thomaz, Edivaldo L.; Doerr, Stefan H.

2014-05-01

The purpose of this study was to evaluate the effects of fire temperatures (i.e., soil heating) on nutrient release and aggregate physical changes in soil. A preliminary conceptual model of nutrient release was established based on results obtained from a controlled burn in a slash-and-burn agricultural system located in Brazil. The study was carried out in clayey subtropical soil (humic Cambisol) from a plot that had been fallow for 8 years. A set of three thermocouples were placed in four trenches at the following depths: 0 cm on the top of the mineral horizon, 1.0 cm within the mineral horizon, and 2 cm within the mineral horizon. Three soil samples (true independent sample) were collected approximately 12 hours post-fire at depths of 0-2.5 cm. Soil chemical changes were more sensitive to fire temperatures than aggregate physical soil characteristics. Most of the nutrient response to soil heating was not linear. The results demonstrated that moderate temperatures (< 400°C) had a major effect on nutrient release (i.e., the optimum effect), whereas high temperatures (> 500 °C) decreased soil fertility.

Fire Alters Emergence of Invasive Plant Species from Soil Surface-Deposited Seeds

USDA-ARS?s Scientific Manuscript database

1. Fire is recognized as an important process controlling ecosystem structure and function. Restoration of fire regimes is complicated by global concerns about exotic plants invasions, yet little is known of how the two may interact. Characterizing relationships between fire conditions and the vi...

Decreases in Soil Moisture and Organic Matter Quality Suppress Microbial Decomposition Following a Boreal Forest Fire

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holden, Sandra R.; Berhe, Asmeret A.; Treseder, Kathleen K.

Climate warming is projected to increase the frequency and severity of wildfires in boreal forests, and increased wildfire activity may alter the large soil carbon (C) stocks in boreal forests. Changes in boreal soil C stocks that result from increased wildfire activity will be regulated in part by the response of microbial decomposition to fire, but post-fire changes in microbial decomposition are poorly understood. Here, we investigate the response of microbial decomposition to a boreal forest fire in interior Alaska and test the mechanisms that control post-fire changes in microbial decomposition. We used a reciprocal transplant between a recently burnedmore » boreal forest stand and a late successional boreal forest stand to test how post-fire changes in abiotic conditions, soil organic matter (SOM) composition, and soil microbial communities influence microbial decomposition. We found that SOM decomposing at the burned site lost 30.9% less mass over two years than SOM decomposing at the unburned site, indicating that post-fire changes in abiotic conditions suppress microbial decomposition. Our results suggest that moisture availability is one abiotic factor that constrains microbial decomposition in recently burned forests. In addition, we observed that burned SOM decomposed more slowly than unburned SOM, but the exact nature of SOM changes in the recently burned stand are unclear. Finally, we found no evidence that post-fire changes in soil microbial community composition significantly affect decomposition. Taken together, our study has demonstrated that boreal forest fires can suppress microbial decomposition due to post-fire changes in abiotic factors and the composition of SOM. Models that predict the consequences of increased wildfires for C storage in boreal forests may increase their predictive power by incorporating the observed negative response of microbial decomposition to boreal wildfires.« less

Fire impacts on European Boreal soils: A review

NASA Astrophysics Data System (ADS)

Pereira, Paulo; Oliva, Marc; Cerda, Artemi

2016-04-01

Fire is an important natural disturbance in boreal ecosystems, fundamental to understand plant distribution (Ryan, 2002; Wallenius et al., 2004; Granstrom, 2001). Nevertheless, nowadays the intense and successful, fire suppression measures are changing their ecological role (Pereira et al., 2013a,b). This is consequence of the lack of understanding of stakeholders and decision makers about the role of the fire in the ecosystems (Mierasukas and Pereira, 2013; Pereira et al., 2016). This fire suppression measures are increasing the amount of fuel accumulation and the risk of severe wildfires, which can increase of frequency and severity in a context of climate change. Fire is a good tool for landscape management and restoration of degraded ecosystems (Toivanen and Kotiaho, 2007). Fire is considered a soil forming factor (Certini, 2014) and in boreal environments it has been observed that low fire severities, do not change importantly soil properties, mean fire severities induce positive impacts on soil, since add an important amounts of nutrients into soil profile and high severity fires had negative impacts due to the high consumption of organic matter (Vanha-Majamaa et al., 2007; Pereira et al., 2014). References Certini, G., 2014. Fire as a soil-forming factor. Ambio, 43, 191-195 Granstrom A. 2001. Fire management for biodiversity in the European Boreal forest. Scandinavian Journal of Forest Research 3: 62-69. Mierauskas, P., Pereira, P. (2013) Stakeholders perception about prescribed fire use in Lithuania. First results, Flamma, 4(3), 157-161. Pereira, P., Cerdà, A., Jordán, A., Bolutiene, V., Úbeda, X., Pranskevicius, M., Mataix-Solera, J. (2013) Spatio-temporal vegetation recuperation after a grassland fire in Lithuania, Procedia Environmental Sciences, 19:856-864 Pereira, P., Mierauskas, P., Ubeda, X., Mataix-Solera, J.,Cerda, A. (2012) Fire in protected areas - the effect of the protection and importance of fire management, Environmental Research, Engineering and Management, 1(59), 52-62. Pereira, P., Ubeda, X., Mataix-Solera, J., Oliva, M., Novara, A. (2014) Short-term spatio-temporal spring grassland fire effects on soil colour,organic matter and water repellency in Lithuania, Solid Earth, 5, 209-225. Ryan KC. 2002. Dynamic Interactions between forest structure and fire behavioural in boreal ecosystems. Silva Fennica 36: 13-39 Toivanen T, Kotiaho JS. 2007. Mimicking natural disturbances of boreal forests: the effects of controlled burning and creating dead wood on beetle diversity. Biodiversity Conservation 16: 3193-3211.

From the study of fire effects on individual soil properties to the development of soil quality indices. 1. The pioneer research

NASA Astrophysics Data System (ADS)

Mataix-Solera, Jorge; Zornoza, Raúl

2013-04-01

Although forest fires must be considered as a natural factor in Mediterranean ecosystems, the modification of its natural regime during last five decades has thansformed them in an environmental problem. In the Valencia region (E Spain) 1994 was the worst year in the history affecting more than 120,000 hectares. I started my Ph.D that year by studying the effects of fires in soil properties. The availability to be able to analyse a great set of different types of soil properties in the laboratories of University of Alicante allowed me to explore how fires could affect physical, chemical and micobiological soil properties. After years studying different soil properties, finding that several factors are involved, including: fire intensity and severity, vegetation, soil type, climate conditions, etc. (Mataix-Solera and Doerr, 2004; Mataix-Solera et al., 2008, 2011) my research as Ph-D supervisor has been focussed to investigate more in depth some selected properties, such as aggregate stability and water repellency (Arcenegui et al., 2007, 2008). But one of the main problems in the studies conducted with samples affected by wildfires is that for the evaluation of the fire impact in the soil it is necessary to have control (unburned) soil samples from a similar non-affected near area. The existing spatial variability under field conditions does not allow having comparable samples in some acses to develop a correct assessment. With this idea in mind one of my Ph.D researcher (R. Zornoza) dedicated his thesis to develope soil quality indices capable to assess the impact of soil perturbations without comparing groups of samples, but evaluating the equilibrium among different soil properties within each soil sample (Zornoza et al., 2007, 2008). Key words: wildfire, Mediterranean soils, soil degradation, wàter repellency, aggregate stability References: Arcenegui, V., Mataix-Solera, J., Guerrero, C., Zornoza, R., Mayoral, A.M., Morales, J., 2007. Factors controlling the water repellency induced by fire in calcareous Mediterranean forest soils. Eur. J. Soil Sci. 58, 1254-1259. Arcenegui, V., Mataix-Solera, J., Guerrero, C., Zornoza, R., Mataix-Beneyto, J., García-Orenes, F., 2008. Immediate effects of wildfires on water repellency and aggregate stability in Mediterranean calcareous soils. Catena 74, 219-226. Mataix-Solera, J., Doerr, S.H., 2004. Hydrophobicity and aggregate stability in calcareous topsoil from fire affected pine forests in southeastern Spain. Geoderma 118, 77-88. Mataix-Solera, J., Arcenegui, V., Guerrero, C., Jordán, M., Dlapa, P., Tessler, N., Wittenberg, L. 2008. Can terra rossa become water repellent by burning? A laboratory approach. Geoderma, 147, 178-184. Mataix-Solera, J., Cerdà, A., Arcenegui, V., Jordán, A., Zavala, L.M., 2011. Fire effects on soil aggregation: a review. Earth-Science Reviews 109, 44-60 Zornoza, R., Mataix-Solera, J., Guerrero, C., Arcenegui, V., Mayoral, A.M., Morales, J. Mataix-Beneyto, J., 2007b. Soil properties under natural forest in the Alicante Province of Spain. Geoderma. 142, 334-341. Zornoza, R., Mataix-Solera, J., Guerrero, C., Arcenegui, V., Mataix-Beneyto, J., Gómez, I., 2008. Validating the effectiveness and sensitivity of two soil quality indices based on natural forest soils under Mediterranean conditions. Soil Biology & Biochemistry. 40, 2079-2087.

Alterations caused to soil organic matter by post-fire rehabilitation actions in a pine forest from doñana national park (southwest Spain)

NASA Astrophysics Data System (ADS)

González-Pérez, José A.; Jiménez-Morillo, Nicasio T.; Jordán, Antonio; Zavala, Lorena M.; Granged, Arturo J. P.; González-Vila, Francisco J.

2016-04-01

Post-fire rehabilitation actions and recovery attempts of burned soils include a range of management practices (tillage, tree logging, reforestation …), in some cases producing an additional damage to that directly caused by fire. Among negative impacts derived from unappropriated rehab practices are the increase soil erosion, loss of soil fertility and alterations in the hydrological cycle. Analytical pyrolysis (Py-GC/MS) is an appropriate technique to study organic matter characteristics within complex matrices. Here this technique is used to study the alterations caused by burning and post-fire rehab plans to soil organic matter (SOM). Fire and post-fire rehab actions impact on SOM is studied in a sandy soil under pine (Pinus pinea) forest that was affected by a severe fire in August 2012 in Doñana National Park (SW Spain). Bulk samples as well as its sieved soil fractions (coarse, 1-2 mm, and fine, <0.05 mm) collected from an undisturbed burned area (B) and in an adjacent burned area after rehab practices (BR) (logging and extraction of burned trees) were studied. An additional adjacent unburned (UB) area was used as a control. Conspicuous differences among bulk samples from the B, BR and UB control areas were found in the relative proportions of the main molecular families obtained by analytical pyrolysis, including alkane/alkene pairs, unspecific aromatic compounds (UAC), peptides, methoxyphenols, fatty acids, carbohydrates, N-compounds and polycyclic aromatic hydrocarbons (PAH). The B site SOM showed lower proportion of lignin methoxyphenols and higher of UAC and PAH than the SOM from the UB site. This indicates that fire produced methoxyphenol de-functionalization, increasing the proportion of recalcitrant compounds. With respect to soil size fractions, in all cases, the coarse fraction showed a high content of carbohydrate-derived compounds and methoxyphenols followed by fatty acids, in line with inputs of new litter from stressed post-fire vegetation (Jiménez-Morillo et al., 2014). The BR soil coarse fraction showed the highest proportion of methoxyphenols whereas that from the UB soil showed the highest value for alkyl compounds. With respect to the fine soil fractions, although SOM composition varied largely from one area to another, it was found generally more altered than in the coarse fractions. SOM from the UB fine fraction shows a high proportion of alkyl compounds and comparatively lower amount of carbohydrate- and lignin-derived ones. The B soil fine fraction did not show a high contribution from alkyl compounds, which may indicate the occurrence of thermal cracking of alkane/alkene linear chains during the forest fire (González-Pérez et al., 2008). The SOM from the BR soil fine fraction was found of a more labile nature (high relative proportions of fatty acids, peptide- and carbohydrate-derived compounds) than that in the UB and B soils. This contribution from labile compounds may be explained by topsoil mixing caused by the post-fire rehab actions i.e. soil tilling/ploughing and burn tree logging and removal. References: González-Pérez JA, González-Vila FJ, González-Vázquez R, Arias ME, Rodríguez J, Knicker H, 2008. Use of multiple biogeochemical parameters to monitor the recovery of soils after forest fires. Organic Geochemistry 39, 940-944. DOI: 10.1016/j.orggeochem.2008.03.014. Jiménez-Morillo NT, González-Pérez JA, Jordán A, Zavala LM, de la Rosa JM, Jiménez-González MA, González-Vila FJ. 2014. Organic matter fractions controlling soil water repellency in sandy soils from the Doñana National Park (Southwestern Spain). Land Degradation & Development. DOI: 10.1002/ldr.2314. Acknowledgements: This study is part of the results of the GEOFIRE and POSTFIRE Projects (CGL2012-38655-C04-01 and CGL2013-47862-C2-1-R respectively) funded by the Spanish Ministry for Economy and Competitiveness. N.T Jiménez-Morillo is funded by a FPI research grant (BES-2013-062573).

Management Impacts on Carbon Dynamics in a Sierra Nevada Mixed Conifer Forest

PubMed Central

Dore, Sabina; Fry, Danny L.; Collins, Brandon M.; Vargas, Rodrigo; York, Robert A.; Stephens, Scott L.

2016-01-01

Forest ecosystems can act as sinks of carbon and thus mitigate anthropogenic carbon emissions. When forests are actively managed, treatments can alter forests carbon dynamics, reducing their sink strength and switching them from sinks to sources of carbon. These effects are generally characterized by fast temporal dynamics. Hence this study monitored for over a decade the impacts of management practices commonly used to reduce fire hazards on the carbon dynamics of mixed-conifer forests in the Sierra Nevada, California, USA. Soil CO2 efflux, carbon pools (i.e. soil carbon, litter, fine roots, tree biomass), and radial tree growth were compared among un-manipulated controls, prescribed fire, thinning, thinning followed by fire, and two clear-cut harvested sites. Soil CO2 efflux was reduced by both fire and harvesting (ca. 15%). Soil carbon content (upper 15 cm) was not significantly changed by harvest or fire treatments. Fine root biomass was reduced by clear-cut harvest (60–70%) but not by fire, and the litter layer was reduced 80% by clear-cut harvest and 40% by fire. Thinning effects on tree growth and biomass were concentrated in the first year after treatments, whereas fire effects persisted over the seven-year post-treatment period. Over this period, tree radial growth was increased (25%) by thinning and reduced (12%) by fire. After seven years, tree biomass returned to pre-treatment levels in both fire and thinning treatments; however, biomass and productivity decreased 30%-40% compared to controls when thinning was combined with fire. The clear-cut treatment had the strongest impact, reducing ecosystem carbon stocks and delaying the capacity for carbon uptake. We conclude that post-treatment carbon dynamics and ecosystem recovery time varied with intensity and type of treatments. Consequently, management practices can be selected to minimize ecosystem carbon losses while increasing future carbon uptake, resilience to high severity fire, and climate related stresses. PMID:26918460

Restoration of a Mediterranean forest after a fire: bioremediation and rhizoremediation field-scale trial.

PubMed

Pizarro-Tobías, Paloma; Fernández, Matilde; Niqui, José Luis; Solano, Jennifer; Duque, Estrella; Ramos, Juan-Luis; Roca, Amalia

2015-01-01

Forest fires pose a serious threat to countries in the Mediterranean basin, often razing large areas of land each year. After fires, soils are more likely to erode and resilience is inhibited in part by the toxic aromatic hydrocarbons produced during the combustion of cellulose and lignins. In this study, we explored the use of bioremediation and rhizoremediation techniques for soil restoration in a field-scale trial in a protected Mediterranean ecosystem after a controlled fire. Our bioremediation strategy combined the use of Pseudomonas putida strains, indigenous culturable microbes and annual grasses. After 8 months of monitoring soil quality parameters, including the removal of monoaromatic and polycyclic aromatic hydrocarbons as well as vegetation cover, we found that the site had returned to pre-fire status. Microbial population analysis revealed that fires induced changes in the indigenous microbiota and that rhizoremediation favours the recovery of soil microbiota in time. The results obtained in this study indicate that the rhizoremediation strategy could be presented as a viable and cost-effective alternative for the treatment of ecosystems affected by fires. © 2014 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

One year monitoring of fire-induced effects on dissolved organic matter and nutrient dynamics under different land-use

NASA Astrophysics Data System (ADS)

Potthast, Karin; Meyer, Stefanie; Crecelius, Anna; Schubert, Ulrich; Michalzik, Beate

2016-04-01

It is supposed that the changing climate will promote extreme weather events that in turn will increase drought periods and the abundance of fire events in temperate climate regions such as Central Europe. The impact of fires on the nutrient budgets of ecosystems is highly diverse and seems to depend on the ecosystem type. For example, little is known about fire effects on water-bound organic matter (OM) and nutrient fluxes in temperate managed forest ecosystems. Fires can strongly alter the distribution (forest floor vs. mineral soil), binding forms (organic vs. inorganic) and availability (solubility by water) of OM and associated nutrients. To elucidate the effects and seasonality of low intensity fires on the mobilization of dissolved organic carbon and nutrients, an experimental ground fire was conducted in November 2014 in the Hainich region, Central Germany. In addition, differences in response patterns between two land-use types (pasture and beech forest) were investigated. Lysimeters (n=5 controls/ 5 fire-manipulated) with topsoil monoliths (0-4 cm), rainfall/throughfall samplers, littertraps as well as temperature and moisture sensors were installed on three sites of each land-use type. During the one year of monitoring (Sep14-Dec15) soil solution, rainfall, and throughfall samples were taken biweekly and analyzed for pH, dissolved and particulate organic carbon (DOC, POC) and nitrogen (DN, PN) as well as for nutrients (e.g. K, Ca, Mg, P, S). Compared to the control sites, the ground fire immediately induced a short-run release peak of DOC in both land-use types. Within two weeks these differences were muted in the post-fire period. The effect of fire was land-use specific with annual DOC fluxes of 82 and 45 kg/(ha*a) for forest and pasture sites, respectively. In contrast, nitrogen fluxes responded differently to the fire event. In the forest, a significant increase in DN concentrations was notable five months after the fire, at the beginning of the vegetation period and lasted until November with DN concentrations in June being 4 times higher compared to the control (82 vs. 18 mg DN/L) and being negatively correlated with pH-values (r=-0.51 p<0.001). Annual DN fluxes from fire manipulated forest plots were two times higher compared to control ones (62 vs. 29 kg DN/(ha*a)) whereas only low impact was found at the pasture with 45 and 38 kg DN/(ha*a) for fire-manipulated plots and control, respectively. In general, the results exhibit highly differing response patterns of elements to fire between the two land-use types and with season. Starting in spring higher DN fluxes following fire event at the forest site could be associated with accelerated activity of soil microbes mineralizing released organic substances from burned forest floor and/or from dead roots. This mineralization process resulted in a significant increase in acidity of the soil solution that may affect important ecosystem functions like nutrient cycling and primary production. Hence, high resolution monitoring following a low intensive fire indicated nutrient losses from the forest ecosystem that could be a hazard for managed forests on nutrient poor soils if fire frequency increases with climate change.

Short-term effects of prescribed fire for pasture management on soil water repellency in the Central Pyrenees (NE-Spain)

NASA Astrophysics Data System (ADS)

Girona García, Antonio; María Armas-Herrera, Cecilia; Martí-Dalmau, Clara; Badía-Villas, David; Ortiz-Perpiñán, Oriol

2016-04-01

The decrease of livestock grazing during the last decades in the Central Pyrenees has led to a regression of grasslands in favour of shrublands, mainly composed by Echinospartum horridum. Prescribed burning might be a suitable tool for the control of this species that limits pastures development and therefore, the reclamation of grasslands; although, its effects on soil properties are still uncertain [1]. Controlled burnings are usually performed in spring or autumn, when soil moisture is high and temperature low, being easier to control and also reducing its effects on soil properties. However, burning during the wet seasons can increase the risk of soil erosion as the vegetation cover is partially destroyed. In this sense, soil water repellency (SWR) plays an important role reducing the infiltration rates and, thus, increasing runoff and soil erosion [2]. Then, it is of special interest to study parameters that influence SWR such as soil moisture, soil organic carbon (SOC) content and soil biological activity [3]. The aim of this work is, to analyse the effects of controlled burning on SWR as well as some of the influencing factors on this parameter. To achieve this, soil sampling was carried out in two prescribed fire events that took place in the Central Pyrenees: Tella (April, 2015) and Buisán (November, 2015). Temperature was simultaneously recorded during the fire via thermocouples placed at the surface level and at 1 cm, 2 cm and 3 cm depth. In each event, topsoil was scrapped and sampled from 0-1 cm, 1-2 cm and 2-3 cm depth in each sampling point (3 for Tella and 4 for Buisán) just before and immediately after burning. We analysed SWR persistence (Water Drop Penetration Time, WDPT) and intensity (Ethanol Percentage Test, EPT) as well as total C and N, microbial C, β-glucosidase activity, soil moisture and pH. Temperature measurements indicated a higher fire intensity in Tella than in Buisán burning. Surface unburned samples presented extreme SWR values for Tella (2726 s) and strong values for Buisán (191 s) according to the WDPT test, significantly decreasing with depth. Preliminary results showed that burning affected SWR, significantly reducing WDPT down to 3 cm in Tella (from extreme to strong) and 2 cm depth in Buisán (from strong to slight). EPT results indicated a significant decrease in SWR intensity down to 2 cm in Tella and 1 cm in Buisán with burning. On the other hand, no differences were observed regarding soil moisture between burned and unburned samples, although a trend to decreasing was observed with fire. Further analyses will allow us to explain and support in detail the variations observed in SWR with prescribed burning. [1] Shakesby, R.A. et al. (2015). Impacts of prescribed fire on soil loss and soil quality: An assessment based on an experimentally-burned catchment in central Portugal. Catena 128: 278-293. [2] Bodí, M.B. et al. (2013). Spatial and temporal variations of water repellency and probability of its occurrence in calcareous Mediterranean rangeland soils affected by fire. Catena 108: 14-25. [3] Jordán, A. et al. (2013). Soil water repellency: Origin, assessment and geomorphological consequences. Catena 108: 1-5.

Post-oil-spill fires at Ugbomro (Niger Delta): a new vista in soil-pollution studies.

PubMed

Osuji, Leo C; Ukale, Eseoghene E

2005-10-01

Reconnaissance of the post-oil-spill, fire-scourged site at Ugbomro, in the Niger Delta, was contingent upon the loud public outcry and galvanizing hue that ensued the widespread conflagration. Sampling was carried out by the grid technique, and fire-scourged soils and their unaffected controls were analyzed. Contrary to the 'celebrated' opinion of some that the fires improvised bush fallowing for cropping, the site had witnessed severe impoverishment as evidenced by the hitherto neglected insidious impact of such infernos on soil macronutrients. Alterations in physico-chemical properties (pH, conductivity, etc.) provided adequate bases for this conclusion, and offered broad explanations for the paucity of macronutrients in affected soils. For instance, a pH range of 3.1-3.8 hindered N2 fixation and other metabolic activities that enhance mineralization. Elaeis guineensis in a density of 3 stands/m2 at the control site was the only tree-form not charred beyond recognition.Against future fires, it is important to strengthen contingencies for more-expedient clean-up responses to oil spills to severe possibilities of in situ conflagrations. Nutrient supplementations, revegetation, and site surveillance should disengage the 'unsighted fingers' of sabotage. A careful husbandry of these measures might re-establish nutrient stability, and forestall future re-occurrence of such effacing incidents.

Fish Mercury Loads and Lake Productivity Are Not Impacted by Wildland Fire in Northern Minnesota

NASA Astrophysics Data System (ADS)

Riggs, C.; Kolka, R. K.; Nater, E. A.; Witt, E.; Wickman, T.; Woodruff, L. G.; Butcher, J.

2016-12-01

Wildland fire can significantly alter mercury (Hg) cycling on land and in adjacent aquatic environments. In addition to enhancing local atmospheric Hg deposition, fire can influence terrestrial movement of Hg and other elements into lakes via runoff from burned upland soil. However, the impact of fire on water quality and the accumulation of Hg in fish remains equivocal. We investigated the effects of fire - specifically a low severity prescribed fire and moderate severity wildfire - on young-of-the-year yellow perch (Perca flavescens) and lake chemistry in two small remote watersheds in the Boundary Waters Canoe Area Wilderness in northeastern Minnesota using a paired watershed approach (fire-impacted vs. control watershed). Prior to fire, surface soil in the two study watersheds contained significant loads of Hg, mainly from atmospheric deposition. We expected fire to increase transport and deposition of Hg from smoke and burned soil into the fire-impacted lake, leading to changes in lake productivity and fish Hg loads. In contrast to our prediction, and despite significant effects of the moderate severity wildfire fire on upland soil Hg stocks, fish Hg accumulation and lake productivity were not affected by fire. Instead, climate and lake water levels were the strongest predictors of lake chemistry and fish responses in our study lakes. Our results suggest that low to moderate severity wildland fire does not alter lake productivity nor Hg accumulation in young-of-the-year yellow perch in these small, shallow lakes in the northern deciduous and boreal forest region. The effect of a high severity fire remains to be tested.

The Impact of Fire on Mercury Cycling in Watershed Systems

NASA Astrophysics Data System (ADS)

Lopez, S.; Mendez, C.; Hogue, T.; Jay, J.

2006-12-01

Mercury methylation is a process by which the less-toxic inorganic mercury is transformed into methylmercury (MeHg). MeHg is a potent neurotoxin with a strong tendency to biomagnify within the food chain. Limited studies suggest that wildfires change the soil characteristics and contribute to Hg transport and possibly methylation in downstream ecosystems. We propose that post-fire Hg cycling can be related to various soil properties and burn characteristics. In order to better understand the effects of wildfires on Hg cycling, studies were undertaken within a burned watershed and a neighboring unburned site, Malibu Creek and Cold Creek, respectively. Soil sampling of the burned and control (unburned) regions were composed of 25 square foot grids with nine equidistant sampling points. Sediment samples for soil sieve analysis were collected at all grid points to determine the particle size distribution of the fine and coarse grain aggregates. Total Hg sediments were collected from the three middle points of the grid at two soil horizons to provide a vertical profile. Total Hg concentrations of the sediment samples were measured using the Direct Mercury Analyzer (DMA80). Initial analysis of the soil profiles reveals a decrease in Hg concentration at the soil surface (89 percent loss). Preliminary results indicate sites with the lowest concentration of Hg are characterized by a higher percentage of finer grain aggregates. Runoff from the first post-fire storm was extremely turbid and dark gray in color due to high levels of suspended solids (3980 mg/L). Total Hg concentrations in unfiltered and filtered samples (0.2 micron) were 196 and 4.7 ng/L, respectively, compared to the control which had unfiltered and filtered Hg levels of 6.1 and 2.3 ng/L, respectively, and 450 mg/L total suspended solids. The concentration of Hg on the particles was six times higher than the Hg content of suspended particles at the control site. Results also show much stronger partitioning (three-fold higher Kd's) to the solid phase in the fire- impacted site. On-going work includes: 1) analysis of Hg and ancillary geochemical parameters overlying water and porewater from samples collected in the streambed downstream of the fire, 2) analysis of Hg concentrations in various particle size fractions of soil; and 3) preliminary characterization of recovery through analysis of soil properties and Hg levels at the burned and control sites, one-year post-fire.

Water repellency and organic matter composition after a wildfire: new insights using thermal analysis

NASA Astrophysics Data System (ADS)

Neris, Jonay; Doerr, Stefan

2014-05-01

Water repellency, a key parameter in the hydrological and ecological behaviour of ecosystems, is one of the main soil properties affected by wildfire through its impact on organic matter (Shakesby and Doerr, 2006). This study examines the link between post-fire organic matter quantity and composition, soil water repellency and related hydrological properties in order to (i) examine the influence of different organic matter pools on soil hydrological properties and (ii) to explore the use of these links as a proxy for soil hydrological impacts of fire. Soil samples from five fire-affected burned and unburned control sites in Andisols terrain in Tenerife, previously studied for water repellency and hydrology-related properties (Neris et al., 2013), were selected and thermogravimetric analysis (TG) carried out to evaluate fire impacts on their organic matter composition. A decrease in the organic matter quantity as well as in the relative amount of the labile organic matter pool and an increase in the recalcitrant and/or refractory pool depending was observed in the burned soils. TG data, using 10 ºC temperature range steps, allowed reasonable prediction of soil properties evaluated, with R2 ranging from 0.4 to 0.8. The labile pool showed a broad and positive influence on most soil properties evaluated, whereas the refractory pool and the dehydration range affected the surface water holding capacity and water repellency. These results, in conjunction with the simplicity of the TG analysis suggest that, following a calibration step to link TG data to the site-specific post-fire soil properties, this method may be a useful tool for rapid and cost-effective soil hydrological response evaluation after the fire. References Neris, J., Tejedor, M., Fuentes, J., Jiménez, C., 2013. Infiltration, runoff and soil loss in Andisols affected by forest fire (Canary Islands, Spain). Hydrological Processes 27(19), 2814-2824. Shakesby, R.A., Doerr, S.H., 2006. Wildfire as a hydrological and geomorphological agent. Earth-Science Reviews 74(3-4), 269-307.

Increasing microbial diversity and nitrogen cycling potential of burnt forest soil in Spain through post-fire management

NASA Astrophysics Data System (ADS)

Pereg, Lily; Mataix-Solera, Jorge; McMillan, Mary; García-Orenes, Fuensanta

2016-04-01

Microbial diversity and function in soils are increasingly assessed by the application of molecular methods such as sequencing and PCR technology. We applied these techniques to study microbial recovery in post-fire forest soils. The recovery of forest ecosystems following severe fire is influenced by post-fire management. The removal of burnt tree stumps (salvage logging) is a common practice in Spain following fire. In some cases, the use of heavy machinery in addition to the vulnerability of soils to erosion and degradation make this management potentially damaging to soil, and therefore to the ecosystem. We hypothesized that tree removal slows down the recovery of soil biological communities including microbial and plant communities and contributes to soil degradation in the burnt affected area. The study area is located in "Sierra de Mariola Natural Park" in Alcoi, Alicante (E Spain). A big forest fire (>500 has) occurred in July 2012. The forest is composed mainly of Pinus halepensis trees with an understory of typical Mediterranean shrubs species such as Quercus coccifera, Rosmarinus officinalis, Thymus vulgaris, Brachypodium retusum, etc. Soil is classified as a Typic Xerorthent (Soil Survey Staff, 2014) developed over marls. In February 2013, salvage logging (SL) treatment, with a complete extraction of the burned wood using heavy machinery, was applied to a part of the affected forest. Plots for monitoring the effects of SL were installed in this area and in a similar nearby control (C) area, where no SL treatment was done. The recovery of soil bacterial and fungal communities post-fire with and without tree removal was analysed by using Next-Generation sequencing and the abundance of functional genes, related to nitrogen cycling, in the soil was estimated using quantitative PCR (qPCR). We will present the methods used and the results of our study in this PICO presentation.

Land-use and fire drive temporal patterns of soil solution chemistry and nutrient fluxes.

PubMed

Potthast, Karin; Meyer, Stefanie; Crecelius, Anna C; Schubert, Ulrich S; Tischer, Alexander; Michalzik, Beate

2017-12-15

Land-use type and ecosystem disturbances are important drivers for element cycling and bear the potential to modulate soil processes and hence ecosystem functions. To better understand the effect of such drivers on the magnitude and temporal patterns of organic matter (OM) and associated nutrient fluxes in soils, continuous flux monitoring is indispensable but insufficiently studied yet. We conducted a field study to elucidate the impact of land-use and surface fires on OM and nutrient fluxes with soil solution regarding seasonal and temporal patterns analyzing short (<3months) and medium-term (3-12months) effects. Control and prescribed fire-treated topsoil horizons in beech forests and pastures were monitored biweekly for dissolved and particulate OM (DOM, POM) and solution chemistry (pH value, elements: Ca, Mg, Na, K, Al, Fe, Mn, P, S, Si) over one post-fire year. Linear mixed model analyses exhibited that mean annual DOM and POM fluxes did not differ between the two land-use types, but were subjected to strong seasonal patterns. Fire disturbance significantly lowered the annual soil solution pH in both land-uses and increased water fluxes, while DOC fluxes remained unaffected. A positive response of POC and S to fire was limited to short-term effects, while amplified particulate and dissolved nitrogen fluxes were observed in the longer run and co-ocurred with accelerated Ca and Mg fluxes. In summary, surface fires generated stronger effects on element fluxes than the land-use. Fire-induced increases in POM fluxes suggest that the particulate fraction represent a major pathway of OM translocation into the subsoil and beyond. With regard to ecosystem functions, pasture ecosystems were less prone to the risk of nutrient losses following fire events than the forest. In pastures, fire-induced base cation export may accelerate soil acidification, consequently exhausting soil buffer systems and thus may reduce the resilience to acidic depositions and disturbances. Copyright © 2017 Elsevier B.V. All rights reserved.

Burning fire-prone Mediterranean shrublands: immediate changes in soil microbial community structure and ecosystem functions.

PubMed

Goberna, M; García, C; Insam, H; Hernández, M T; Verdú, M

2012-07-01

Wildfires subject soil microbes to extreme temperatures and modify their physical and chemical habitat. This might immediately alter their community structure and ecosystem functions. We burned a fire-prone shrubland under controlled conditions to investigate (1) the fire-induced changes in the community structure of soil archaea, bacteria and fungi by analysing 16S or 18S rRNA gene amplicons separated through denaturing gradient gel electrophoresis; (2) the physical and chemical variables determining the immediate shifts in the microbial community structure; and (3) the microbial drivers of the change in ecosystem functions related to biogeochemical cycling. Prokaryotes and eukaryotes were structured by the local environment in pre-fire soils. Fire caused a significant shift in the microbial community structure, biomass C, respiration and soil hydrolases. One-day changes in bacterial and fungal community structure correlated to the rise in total organic C and NO(3)(-)-N caused by the combustion of plant residues. In the following week, bacterial communities shifted further forced by desiccation and increasing concentrations of macronutrients. Shifts in archaeal community structure were unrelated to any of the 18 environmental variables measured. Fire-induced changes in the community structure of bacteria, rather than archaea or fungi, were correlated to the enhanced microbial biomass, CO(2) production and hydrolysis of C and P organics. This is the first report on the combined effects of fire on the three biological domains in soils. We concluded that immediately after fire the biogeochemical cycling in Mediterranean shrublands becomes less conservative through the increased microbial biomass, activity and changes in the bacterial community structure.

Key factors controlling microbial community response after a fire: importance of severity and recurrence

NASA Astrophysics Data System (ADS)

Lombao, Alba; Barreiro, Ana; Martín, Ángela; Díaz-Raviña, Montserrat

2015-04-01

Microorganisms play an important role in forest ecosystems, especially after fire when vegetation is destroyed and soil is bared. Fire severity and recurrence might be one of main factors controlling the microbial response after a wildfire but information about this topic is scarce. The aim of this study is to evaluate the influence of fire regimen (recurrence and severity) on soil microbial community structure by means of the analysis of phospholipid fatty acid (PLFA). The study was performed with unburned and burned samples collected from the top layer of a soil affected by a high severity fire (Laza, NW Spain) heated under laboratory conditions at different temperatures (50°C, 75°C, 100°C, 125°C, 150°C, 175°C, 200°C, 300°C) to simulate different fire intensities; the process was repeated after further soil recovery (1 month incubation) to simulate fire recurrence. The soil temperature was measured with thermocouples and used to calculate the degree-hours as estimation of the amount of heat supplied to the samples (fire severity). The PLFA analysis was used to estimate total biomass and the biomass of specific groups (bacteria, fungi, gram-positive bacteria and gram-negative bacteria) as well as microbial community structure (PLFA pattern) and PLFA data were analyzed by means of principal component analysis (PCA) in order to identify main factors determining microbial community structure. The results of PCA, performed with the whole PLFA data set, showed that first component explained 35% of variation and clearly allow us to differentiate unburned samples from the corresponding burned samples, while the second component, explaining 16% of variation, separated samples according the heating temperature. A marked impact of fire regimen on soil microorganisms was detected; the microbial community response varied depending on previous history of soil heating and the magnitude of changes in the PLFA pattern was related to the amount of heat supplied to the samples. Thus, wildfire was the main factor determining the microbial community structure followed, in less extent, by fire severity. The total biomass and the biomass of specifics microbial groups decreased notably as consequence of wildfire and minor changes were detected due to soil heating under laboratory conditions. The results clearly showed the usefulness of PLFA pattern combined with PCA to study the relationships between fire regimen (recurrence and severity) and associated direct and indirect changes in soil microorganisms. The data also indicated that degree-hours methodology rather than temperature is adequate for evaluating the impact of soil heating on microbial communities. Keywords: wildfire, heating temperature, degree-hours, PLFA pattern, microbial biomass Acknowledgements. This study was supported by the Ministerio Español de Economía y Competitividad (AGL2012-39688-C02-01). A Lombao is recipient of FPU grant from Ministerio Español de Educación.

Prescribed fires effects on physico-chemical properties and quantity of runoff and soil erosion in a Mediterranean forest

NASA Astrophysics Data System (ADS)

Esteban Lucas-Borja, Manuel; Plaza Alvaréz, Pedro Antonio; Sagra, Javier; Alfaro Sánchez, Raquel; Moya, Daniel; Ferrandiz Gotor, Pablo; De las Heras Ibañez, Jorge

2017-04-01

Wildfires have an important influence in forest ecosystems. Contrary to high severity fire, which may have negative impacts on the ecosystems, low severity induce small changes on soil properties. Thus and in order to reduce fire risk, low-severity prescribed fires have been widely used as a fuel reduction tool and silvicultural treatment in Mediterranean forest ecosystems. However, fire may alter microsite conditions and little is known about the impact of prescribed burning on the physico-chemical properties of runoff. In this study, we compared the effects of prescribed burning on physico-chemical properties and quantity of runoff and soil erosion during twelve months after a low severity prescribed fire applied in twelve 16 m2 plot (6 burned plots and 6 control plots used for comparison) set up in the Lezuza forest (Albacete, central-eastern Spain). Physico-chemical properties and quantity of runoff and soil losses were monitored after each rainfall event (five rainfall events in total). Also, different forest stand characteristics (slope, tree density, basal area and shrub/herbal cover) affecting each plot were measured. Results showed that forest stand characteristics were very similar in all used plots. Also, physico-chemical runoff properties were highly modified after the prescribed fire, increasing water pH, carbonates, bicarbonates, total dissolved solids and organic matter content dissolved in water. Electrical conductivity, calcium, sodium, chloride and magnesium were not affected by prescribed fire. Soil losses were highly related to precipitation intensity and tree interception. Tree intercepted the rainfall and significantly reduced soil losses and also runoff quantity. In conclusion and after the first six-month experiment, the influence of prescribed fires on physico-chemical runoff properties should be taken into account for developing proper prescribed burnings guidelines.

Determining the Limiting Factors Controlling Soil Ecosystem Regeneration After a Stand-replacing Wildfire

NASA Astrophysics Data System (ADS)

Cooperdock, S.; Breecker, D.

2016-12-01

Like all forest disturbances, wildfires remove vegetation but additionally they can remove or transform soil nutrients through volatilization due to extreme temperatures. As the stability and nutrient source for plants, soils are the key to forest regeneration after disturbances and in order to predict and mitigate damage, it is essential to understand how soils are affected by fires. In this study, soil respiration and temperature were measured in-situ at 20 sites affected by two fires that occurred during September 2011 and October 2015 in Bastrop County TX. At each site, soil samples were collected from 0-5 cm depth. These samples were incubated in the dark at 25° C and 22% water content to determine respiration rates under controlled environmental conditions. Total C, N, trace element concentrations and pH were measured in each soil sample to determine the effect of fire on soil chemistry and the effect of soil chemistry on soil activity. These methods of respiration measurement were performed to distinguish the impact of environmental and chemical factors on soil biological activity. Results show that from May to July 2016, soil temperatures increased an average of 6° C and 1° C more in burned areas than in unburned areas at depths of 5 cm and 15 cm, respectively. This likely results from fire-induced decrease in overstory cover, decrease in organic matter insulation and darkening soil color. Increasing temperatures correspond with a decrease in water content and respiration. Pearson's tests of the effect of soil moisture loss on a decrease of in-situ respiration rate show a correlation for burned soils, especially at sites burned in both fires (rho=0.90, p=0.04) and no correlation for unburned soils, suggesting a larger impact of environmental factors on soil activity in burned soils. Microcosm experiments show N concentration significantly affects respiration rate in unburned plots (rho=0.89, p=0.04) and both N (rho=0.92, p=0.03) and C concentration (rho=0.92, p=0.03) affect respiration rate in plots burned in 2011. No correlation was detected between nutrient concentration and respiration rate in recently burned plots, suggesting a larger influence of nutrient limitation on regeneration as time since burn increases. These results reveal that the limiting factors governing soil activity shift after wildfires.

Impact of a low severity fire on soil organic carbon and nitrogen characteristics in Japanese cedar soil Yamagata Prefecture, Japan

NASA Astrophysics Data System (ADS)

Seidel, Felix

2017-04-01

Slash and burn practices are widely used around the globe with different degrees of success which are mostly related to the impact of fire on the soil properties. In Japan slash and burn practises, known as Yakihata, have a long history and are still used in Yamagata Prefecture today. The purpose of this study was to determine the impact of a low severity controlled fire on Japanese cedar (Cryptomeria japonica) forest soil (Cambisol) which is the dominant species among plantations in Japan. We measured organic carbon and nitrogen content as well as changes in carbon (δ13C) and nitrogen (δ15N) stable isotope composition in a steep west facing slope under heavy precipitation ( 2600 mm/a) and heavy snowfall ( 3-4 m/a). The results show that Ctotal and Ntotal values as well as the isotopes ratios of C and N change with decreasing elevation in the forest as well as in the burned site being consistent with leaching and erosion. The accumulation of Ctotal and Ntotal at the bottom of the slopes was remarkably higher at the slash and burned site than in the control forest site. After slash and burn δ15N isotopes in the slope in general became significantly lighter than in the control forest while the δ13C did not show any significant difference between the two sites except at the bottom of the slopes where δ13C was heavier in the forest. The reason for these changes in nitrogen and carbon isotopes appears to be related to the physical changes in soil horizon sequence of the original forest soil layer. Keywords: high precipitation, Japanese cedar forest soil, low severity fire, stable isotopes, steep slopes

Overview of Considerations in Assessing the Biomass Potential of Army Installations.

DTIC Science & Technology

1981-08-01

stage. Will the species grow well in poor soils and on harsh, open sites? Trees that met these standards were then grouped according to their...frequency of fire, (2) reduces the need of fire control methods such as controlled burns, and (3) makes site preparation easier.21 Whole-tree chipping...the "aesthetic" value of the stand is increased.22 The negative effect most often thought to occur with whole-tree chipping is loss of soil nutrients

Impact of prescribed fire and other factors on cheatgrass persistence in a Sierra Nevada ponderosa pine forest

USGS Publications Warehouse

Keeley, J.E.; McGinnis, T.W.

2007-01-01

Following the reintroduction of fire Bromus tectorum has invaded the low elevation ponderosa pine forests in parts of Kings Canyon National Park, California. We used prescribed burns, other field manipulations, germination studies, and structural equation modelling, to investigate how fire and other factors affect the persistence of cheatgrass in these forests. Our studies show that altering burning season to coincide with seed maturation is not likely to control cheatgrass because sparse fuel loads generate low fire intensity. Increasing time between prescribed fires may inhibit cheatgrass by increasing surface fuels (both herbaceous and litter), which directly inhibit cheatgrass establishment, and by creating higher intensity fires capable of killing a much greater fraction of the seed bank. Using structural equation modelling, postfire cheatgrass dominance was shown to be most strongly controlled by the prefire cheatgrass seedbank; other factors include soil moisture, fire intensity, soil N, and duration of direct sunlight. Current fire management goals in western conifer forests are focused on restoring historical fire regimes; however, these frequent fire regimes may enhance alien plant invasion in some forest types. Where feasible, fire managers should consider the option of an appropriate compromise between reducing serious fire hazards and exacerbating alien plant invasions. ?? IAWF 2007.

Short Term Soil Respiration Response to Fire in a Semi-arid Ecosystem

NASA Astrophysics Data System (ADS)

Rozin, A. G.

2015-12-01

In the Intermountain West (USA), fire is an important driver of carbon cycling in the environment. Increasing frequency and severity of fires, either through management actions or wildfires, is expected with changing climates in the Western United States. When burning is used as a management tool, it may be beneficial and control the growth of nuisance vegetation, promote the regeneration of grasses and forage species, and reduce hazardous fuel loads to minimize the risk of future wildfires. However, high intensity wildfires often have a negative effect, resulting in a loss of carbon storage and a shift of vegetation communities. This delays recovery of the ecosystem for years or decades and alters the historic fire regime. A 2000 acre prescribed burn in the Reynolds Creek Critical Zone Observatory provided the opportunity to quantify pre and post-burn soil carbon stores and soil carbon losses by heterotrophic respiration. Pre and post-burn soil samples were collected for physical and biogeochemical characterization to quantify substrate availability and possible limitations for heterotrophic respiration. CO2 fluxes were continuously monitored in situ before and immediately after the fire to understand the short-term response of soil respiration to varying burn severities.

Controlled burn and immediate mobilization of potentially toxic elements in soil, from a legacy mine site in Central Victoria, Australia.

PubMed

Abraham, Joji; Dowling, Kim; Florentine, Singarayer

2018-03-01

Conducting controlled burns in fire prone areas is an efficient and economic method for forest management, and provides relief from the incidence of high severity wild fires and the consequent damage to human property and ecosystems. However, similar to wild fires, controlled burns also affect many of the physical and biogeochemical properties of the forest soil and may facilitate remobilization of potentially toxic elements (PTEs) sequestered in vegetation and soil organic matter. The objective of the current study is to investigate the mobilization of PTEs, in Central Victorian forest soils in Australia after a controlled burn. Surface soil samples were collected two days before and after the controlled burn to determine the concentration of PTEs and to examine the physicochemical properties. Results show that As, Cd, Mn, Ni and Zn concentrations increased 1.1, 1.6, 1.7, 1.1 and 1.9 times respectively in the post-burn environment, whereas the concentrations of Hg, Cr and Pb decreased to 0.7, 0.9 and 0.9 times respectively, highlighting considerable PTE mobility during and after a controlled burn. Whilst these results do not identify very strong correlations between physicochemical properties of soil and PTEs in the pre- and post-burn environments, PTEs themselves demonstrated very strong and significant correlations. The mobilization of As, Hg and other toxic elements raise potential health concerns as the number of controlled burns are projected to increase in response to climate change. Due to this increased level of PTE release and remobilization, the use of any kinds of controlled burn must be carefully considered before being used as a forest management strategy in mining-affected landscapes which include areas with high PTE concentrations. Copyright © 2017 Elsevier B.V. All rights reserved.

Living more safely in the chaparral-urban interface

Treesearch

Klaus W. H. Radtke

1983-01-01

Urban encroachment into chaparral areas has accelerated the fire-flood-erosion cycle. Preventative maintenance measures can help reduce the damage from fire and flood. This report describes the chaparral environment; how to cope with problems in watershed management, how to landscape for fire and soil erosion control, how to plan for home safety from fire, how to treat...

Significant or negligible sediment and nutrient losses after fire? Pre- and post-fire comparisons

NASA Astrophysics Data System (ADS)

Shakesby, R. A.; Ferreira, A. J. D.; Ferreira, C. S. S.; Stoof, C. R.; Urbanek, E.; Walsh, R. P. D.

2009-04-01

Prescribed fire (or a controlled burn) is a management tool used in wildfire-prone areas to reduce the fuel load of living and dead biomass, while attempting to keep disturbance of the ground surface and soil to a minimum. We know that wildfire, particularly of moderate or extreme severity, can cause important changes to the chemical and physical properties of soil, typically leading to a reduction in aggregate stability, surface roughness and water storage capacity, and an increase in overland flow. It has also been shown that wildfire disturbance can cause major loss of soil, particularly at plot and hillslope scales. There is less information on soil losses at catchment scales, but it is known that losses particularly of organic-rich fine sediment and nutrients can undergo hillslope to channel transfer, where they can affect water quality. Far less research has been carried out into the effects of prescribed fire on soil and nutrient losses at all scales, but particularly at catchment scales. This paper considers the impact of an experimental fire (equivalent to a severe prescribed fire) on soil and nutrient losses. These losses have been monitored at a range of scales (small rainfall simulation plots, long-term erosion plot, erosion plot, hillslope sediment traps (sediment fences) and catchment) before and after the fire in a 10-ha catchment near Góis, central Portugal, which forms part of the 5-year DESIRE research programme concerning desertification and its mitigation at a range of study sites worldwide. The catchment has steep slopes covered mainly with scrub vegetation ranging from c. 0.15 to 2m in height. The soil is thin, stony and highly water repellent. Long-term pre-burn erosion rates are known from a c. 10-year record of soil losses from a small erosion plot (8 x 2m in size) and sediment accumulation in the weir pool of a subcatchment gauging station. Rainfall simulations carried out under dry and wet antecedent conditions before and after the fire, eroded soil collected in sediment fences installed in strategic locations on the catchment slopes and suspended sediment and bedload determinations at the catchment gauging station provide the evidence for pre- and post-fire erosional losses. Comparison with wildfire effects is provided by instrumented scrub-covered hillslopes burnt in early summer 2008 in the same area. In addition to monitoring soil losses in the small catchment, losses of selected nutrients in eroded soil and runoff together with determinations of pre- and post-fire vegetation cover, fuel loads and soil water repellency have been determined. The soil degradational implications are discussed and placed in the context of the literature on prescribed fire and wildfire impacts from elsewhere in the Mediterranean and from further afield.

Community composition of soil bacteria nearly a decade after a fire in a tropical rainforest in East Kalimantan, Indonesia.

PubMed

Isobe, Kazuo; Otsuka, Shigeto; Sudiana, Imade; Nurkanto, Arif; Senoo, Keishi

2009-10-01

Soil bacterial community compositions in burnt and unburnt areas in a tropical rainforest in East Kalimantan, Indonesia, were investigated 8 and 9 years after a fire by denaturing gradient gel electrophoresis analysis targeting the 16S rRNA gene. Three study sites were set in the forest area devoid of fire damage (control), and in the lightly damaged and heavily damaged forest areas. Succession of aboveground vegetation in the two damaged areas had clearly proceeded after the fire, but the vegetation types still differed from the unburnt area at the time of this study. Community composition of total soil bacteria was similar among the three areas, and so was that of actinobacteria. However, the composition of ammonia oxidizing bacteria clearly differed depending on the presence or absence of past fire damage. These results indicate that even nearly a decade after the forest fire, impacts of the fire remained on the community composition of ammonia oxidizing bacteria, but not apparently on those of dominant bacteria and actinobacteria.

Impact of a prescribed fire on soil water repellency in a Banksia woodland (Western Australia)

NASA Astrophysics Data System (ADS)

Muñoz-Rojas, Miriam; Miller, Ben; Tangney, Ryan; Miller, Russell; González-Pérez, José A.; Jiménez-Morillo, Nicasio T.; Zavala, Lorena M.; Jordán, Antonio

2016-04-01

INTRODUCTION The Swan Coastal plain of Western Australia is dominated by fire-prone banksia woodland (Burrows and McCaw, 1990). In these areas, prescription burning is often used to reduce the risk of wildfires, by reducing available fuels (Boer et al., 2009). Little research has been conducted on the effects of prescription burning on Banksia woodlands, and, in particular, information on the impacts on soil properties and soil water repellency (SWR) is scarce. Here, we have studied the impact of fire on SWR in a Banksia woodland and monitored its evolution in the medium-term. It is expected that results are useful for management and restoration of fire-affected Banksia woodlands. METHODS An experimental fire was conducted on May 7th 2015 in Kings Park, Perth, Western Australia. The fire affected an area of 6 ha of mixed Banksia/Allocasuarina woodland under moderate fire intensity. At the time of ignition, the wind speed below the canopy was 1.2 km/h. During the prescribed burning, air temperatures were on average 20 ± 1 °C and relative humidity ranged between 45 and 55% (measured using a Kestrel portable weather station). Fuel moisture averaged 11.8% (measured using Wiltronics moisture meter) and soil moisture at 1 cm deep ranged from 0.1% to 8.6% (measured with a PR2 soil profile probe attached to a HH2 data logger). Temperatures greater than 120 °C were measured 1 cm below the soil surface using iButton temperature sensors. SWR was measured under lab conditions in oven-dry samples (48 h, 105 °C) with the water drop penetration time (WDPT) test. Soil microbial activity was determined with the 1-day CO2 test that is based on the measurement of the CO2 burst produced after moistening dry soil (Muñoz-Rojas et al., 2016). PRELIMINARY RESULTS AND DISCUSSION SWR was severe in the control (mean WDPT = 2608 s) and pre-burned areas (2722 s). One week after the prescribed fire, persistence of soil water repellency remained stable in the burned area (2402 s). In contrast, extreme SWR was observed in the burned area (3750 s). This may be explained by a reduction of water repellency by burning (Zavala et al., 2009; Jordán et al., 2014), as environmental conditions led to an increase in control areas. Although prescribed burning usually do not produce high severity fires, evidences of high severity were found, due to prolonged smouldering caused by subsurface Banksia root clusters. In some cases, this led to release of iron oxides, observed as red spots in the surface. Fire in Mediterranean and semi-arid environments has a significant effect on microbial biomass and the composition of soil microbial communities during the post-fire period, when soil nutrients become available (Bárcenas-Moreno et al., 2011; Muñoz-Rojas et al., 2016). In our study, microbial activity increased sharply in the burned area and most likely contributed to a decrease of organic hydrophobic substances in the first centimetres of the soil profile. Bárcenas-Moreno et al. (2011) observed that bacterial activity increases immediately after fire, while fungi decreased and recovered slowly. These processes may contribute to explain differences in SWR following fire, since this soil property may be influenced by fungal activity (Lozano et al., 2013). ACKNOWLEDGEMENTS This research has been partly funded by the University of Western Australia through the project "Soil water repellence in biodiverse semiarid environments: new insights and implications for ecological restoration" (UWA Research Collaboration Awards, Ref. ENV.2013.6.2-4) and the Spanish Ministry for Economy and Competitiveness through the research projects GEOFIRE (Ref. CGL2012-38655-C04-01) and POSTFIRE (Ref. CGL2013-47862-C2-1-R). REFERENCES Bárcenas-Moreno G, García-Orenes F, Mataix-Solera J, Mataix-Beneyto J, Bååth E. 2011. Soil microbial recolonisation after a fire in a Mediterranean forest. Biology and Fertility of Soils 47: 261-272. DOI: 10.1007/s00374-010-0532-2. Boer MM, Sadlet RJ, Wittkuhn RS, McCaw L, Grierson PF. 2009. Long-term impacts of prescribed burning on regional extent and incidence of wildfires - evidence from 50 years of active fire management in sw australian forests. Forest Ecology and Management 259: 132-142. DOI: 10.1016/j.foreco.2009.10.005. Burrows ND, McCaw WL. 1990. Fuel characteristics and bushfire control in banksia low woodlands in western australia. Journal of Environmental Management 31: 229-236. DOI: 10.1016/S0301-4797(05)80036-2. Jordán A, Gordillo-Rivero AJ, García-Moreno J, Zavala LM, Granged AJP, Gil J, Neto-Paixão HM. 2014. Post-fire evolution of water repellency and aggregate stability in Mediterranean calcareous soils: A 6-year study. Catena 118:115-123. DOI: 10.1016/j.catena.2014.02.001. Lozano E, Jiménez-Pinilla P, Mataix-Solera J, Arcenegui V, Bárcenas GM, González-Pérez JA, García-Orenes F, Torres MP, Mataix-Beneyto J. 2013. Biological and chemical factors controlling the patchy distribution of soil water repellency among plant species in a Mediterranean semiarid forest. Geoderma 207-208:212-220. DOI: 10.1016/j.geoderma.2013.05.021. Muñoz-Rojas M, Erickson TE, Martini D, Dixon KW, Merritt DJ. 2016. Soil physicochemical and microbiological indicators of short, medium and long term post-fire recovery in semi-arid ecosystems. Ecological Indicators 63:14-22. DOI: 10.1016/j.ecolind.2015.11.038. Zavala LM, Jordán A, Gil J, Bellinfante N, Pain C. 2009. Intact ash and charred litter reduces susceptibility to rain splash erosion post-wildfire. Earth Surface Processes and Landforms 34: 1522-1532. DOI: 10.1002/esp.1837.

Effect of post-fire salvage logging treatments on micobiological properties of two different soils in the Povince of Alicante.

NASA Astrophysics Data System (ADS)

Arcenegui, Victoria

2017-04-01

It is well known that the natural wildfire regime in Mediterranean forests is greatly disturbed by human activities. Fire can induce temporal or permanent changes in the soil (see Certini, 2005) and can retard or compromise the recovery of the ecosystem afterwards. Changes in soil properties and the impact on soil functions depend mainly on the severity of the fires (Neary et al., 1999) and type of soil and weather during and after burning (Robichaud & Hungerford, 2000). Post-fire management can have an additional impact on the ecosystem; in some cases, even more severe than the fire. Post-fire salvage logging treatments are very frequently but its ecological impact is uncertain. Mainly because there are so many variables at play. A research has been done in "Sierra de Mariola Natural Park" in Alcoi (M) and ''Cabo de San Antonio'' in Javea (J), both in the Province of Alicante (E Spain). A big forest fire (>500 has) occurred in July 2012 and in September 2014 respectively. After fire, salvage logging (SL) treatment were done. In the first area (M), with a soil classified as Typic Xerorthent, extraction of the burned wood using heavy machinery was applied. In contrast, in the second area (J), a Rhodoxeralf soil, not heavy machinery was used. Plots for monitoring this effect were installed in both areas and in a similar nearby area where no treatment was done, and then used as control (C) for comparison. Soil samplings were done immediately after treatment and 4 years and two years in M site and J site respectively. We examined the effect of salvage logging on basal soil respiration (BSR), and microbial biomass carbon (Cmic). Our results showed that in site M four years after the treatment, the plots without treatment showed a much better improvement for the properties monitored. And not differences were found in site J after two years of monitoring. The impact of salvage logging was different depending on the soil type and the way to do the treatment.

Impact of fire disturbance on soil thermal and carbon dynamics in Alaskan Tundra and Boreal forest ecosystems

NASA Astrophysics Data System (ADS)

Jiang, Y.; Rastetter, E.; Shaver, G. R.; Rocha, A. V.

2012-12-01

In Alaska, fire disturbance is a major component influencing the soil water and energy balance in both tundra and boreal forest ecosystems. Fire-caused changes in soil environment further affect both above- and below-ground carbon cycles depending on different fire severities. Understanding the effects of fire disturbance on soil thermal change requires implicit modeling work on the post-fire soil thawing and freezing processes. In this study, we model the soil temperature profiles in multiple burned and non-burned sites using a well-developed soil thermal model which fully couples soil water and heat transport. The subsequent change in carbon dynamics is analyzed based on site level observations and simulations from the Multiple Element Limitation (MEL) model. With comparison between burned and non-burned sites, we compare and contrast fire effects on soil thermal and carbon dynamics in continuous permafrost (Anaktuvik fire in north slope), discontinuous permafrost (Erickson Creek fire at Hess Creek) and non-permafrost zone (Delta Junction fire in interior Alaska). Then we check the post-fire recovery of soil temperature profiles at sites with different fire severities in both tundra and boreal forest fire areas. We further project the future changes in soil thermal and carbon dynamics using projected climate data from Scenarios Network for Alaska & Arctic Planning (SNAP). This study provides information to improve the understanding of fire disturbance on soil thermal and carbon dynamics and the consequent response under a warming climate.

Salvage logging effect on soil properties in a fire-affected Mediterranean forest: a two years monitoring research

NASA Astrophysics Data System (ADS)

Mataix-Solera, Jorge; Moltó, Jorge; Arcenegui, Vicky; García-Orenes, Fuensanta; Chrenkovà, Katerina; Torres, Pilar; Jara-Navarro, Ana B.; Díaz, Gisela; Izquierdo, Ezequiel

2015-04-01

In the Mediterranean countries, forest fires are common and must be considered as an ecological factor, but changes in land use, especially in the last five decades have provoked a modification in their natural regime. Moreover, post-fire management can have an additional impact on the ecosystem; in some cases, even more severe than the fire. Salvage logging is a traditional management in most fire-affected areas. In some cases, the way of doing it, using heavy machinery, and the vulnerability of soils to erosion and degradation make this management potentially very agresive to soil, and therefore to the ecosystem. Very little research has been done to study how this treatment could affect soil health. In this research we show 2 years of monitoring of some soil properties in an area affected by a forest fire, where some months later this treatment was applied. The study area is located in 'Sierra de Mariola Natural Park' in Alcoi, Alicante (E Spain). A big forest fire (>500 has) occurred in July 2012. The forest is composed mainly of Pinus halepensis trees with an understory of typical Mediterranean shrubs species such as Quercus coccifera, Rosmarinus officinalis, Thymus vulgaris, Brachypodium retusum, etc. Soil is classified as a Typic Xerorthent (Soil Survey Staff, 2014) developed over marls. In February 2013, salvage logging (SL) treatment consisting in a complete extraction of the burned wood using heavy machinery was applied in a part of the affected forest. Plots for monitoring this effect were installed in this area and in a similar nearby area where no treatment was done, and then used as control (C) for comparison. Soil samplings were done immediately after treatment and every 6 months. Some soil properties were analysed, including soil organic matter (SOM) content, basal soil respiration (BSR), microbial biomass carbon (MBC), bulk density (BD), soil water repellency (SWR), aggregate stability (AS), field capacity, nitrogen, etc. After two years of research, results showed significant soil degradation as a consequence of the salvage logging treatment. Most of the soil parameters studied showed differences between control and salvage logging treatments, SOM content in first 2.5 cm of topsoil being less than half in SL plots in comparison with C plots. BSR, MBC and AS were also statistically significant lower in SL plots. BD increased as a consequence of SL treatment. In conclusion, we can affirm that with this type of soil, which is very vulnerable to soil degradation, this treatment has a very negative effect on the ecosystem; this was also reflected in the abundance and diversity of plant species. Acknowledgements: to the 'Ministerio de Economía and Competitividad' of Spanish Government for finance the POSTFIRE project (CGL2013- 47862-C2-1-R), Spanish Soil Science Society, FUEGORED, Alcoi council, ACIF Alcoi, and Sierra de Mariola Natural Park for their support.

Wildfire Risk Mapping over the State of Mississippi: Land Surface Modeling Approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cooke, William H.; Mostovoy, Georgy; Anantharaj, Valentine G

2012-01-01

Three fire risk indexes based on soil moisture estimates were applied to simulate wildfire probability over the southern part of Mississippi using the logistic regression approach. The fire indexes were retrieved from: (1) accumulated difference between daily precipitation and potential evapotranspiration (P-E); (2) top 10 cm soil moisture content simulated by the Mosaic land surface model; and (3) the Keetch-Byram drought index (KBDI). The P-E, KBDI, and soil moisture based indexes were estimated from gridded atmospheric and Mosaic-simulated soil moisture data available from the North American Land Data Assimilation System (NLDAS-2). Normalized deviations of these indexes from the 31-year meanmore » (1980-2010) were fitted into the logistic regression model describing probability of wildfires occurrence as a function of the fire index. It was assumed that such normalization provides more robust and adequate description of temporal dynamics of soil moisture anomalies than the original (not normalized) set of indexes. The logistic model parameters were evaluated for 0.25 x0.25 latitude/longitude cells and for probability representing at least one fire event occurred during 5 consecutive days. A 23-year (1986-2008) forest fires record was used. Two periods were selected and examined (January mid June and mid September December). The application of the logistic model provides an overall good agreement between empirical/observed and model-fitted fire probabilities over the study area during both seasons. The fire risk indexes based on the top 10 cm soil moisture and KBDI have the largest impact on the wildfire odds (increasing it by almost 2 times in response to each unit change of the corresponding fire risk index during January mid June period and by nearly 1.5 times during mid September-December) observed over 0.25 x0.25 cells located along the state of Mississippi Coast line. This result suggests a rather strong control of fire risk indexes on fire occurrence probability over this region.« less

Control of depth to permafrost and soil temperature by the forest floor in black spruce/feathermoss communities.

Treesearch

C.T. Dyrness

1982-01-01

Changes in depth to permafrost and soil temperature were investigated for 4 years after treatment of the forest floor on small plots by fire and mechanical removal of half the forest floor layer and the entire layer. The only treatments to show a consistent, statistically significant effect were the mechanical removals. Fire treatments usually did not have a...

Climate, soil organic layer, and nitrogen jointly drive forest development after fire in the North American boreal zone

NASA Astrophysics Data System (ADS)

Trugman, A. T.; Fenton, N. J.; Bergeron, Y.; Xu, X.; Welp, L. R.; Medvigy, D.

2016-09-01

Previous empirical work has shown that feedbacks between fire severity, soil organic layer thickness, tree recruitment, and forest growth are important factors controlling carbon accumulation after fire disturbance. However, current boreal forest models inadequately simulate this feedback. We address this deficiency by updating the ED2 model to include a dynamic feedback between soil organic layer thickness, tree recruitment, and forest growth. The model is validated against observations spanning monthly to centennial time scales and ranging from Alaska to Quebec. We then quantify differences in forest development after fire disturbance resulting from changes in soil organic layer accumulation, temperature, nitrogen availability, and atmospheric CO2. First, we find that ED2 accurately reproduces observations when a dynamic soil organic layer is included. Second, simulations indicate that the presence of a thick soil organic layer after a mild fire disturbance decreases decomposition and productivity. The combination of the biological and physical effects increases or decreases total ecosystem carbon depending on local conditions. Third, with a 4°C temperature increase, some forests transition from undergoing succession to needleleaf forests to recruiting multiple cohorts of broadleaf trees, decreasing total ecosystem carbon by ˜40% after 300 years. However, the presence of a thick soil organic layer due to a persistently mild fire regime can prevent this transition and mediate carbon losses even under warmer temperatures. Fourth, nitrogen availability regulates successional dynamics; broadleaf species are less competitive with needleleaf trees under low nitrogen regimes. Fifth, the boreal forest shows additional short-term capacity for carbon sequestration as atmospheric CO2 increases.

Wildfires effects on soils: water repellency, NIR models and post-fire treatments. My personal view (SSS Division Outstanding ECS Award Lecture)

NASA Astrophysics Data System (ADS)

Arcenegui, Victoria

2017-04-01

I first was intrigued by fire, because all summers we had some of them in our location, and then I was involve in fire effects on soils. We had, and also have, a lot of question to answer. I am absolutely sure that soil science was my best choice. Soils are amazing, a lot of things are happening in soils. Soils and fire, are my main research topics. I studied the immediately effect of fire on soils, focus on the effect of fire in soil water repellency and aggregate stability. Two physical properties that are crucial to post-fire soil response. I also construct NIR models to know the maximum temperature reached in soils. It is well known that temperature is a key factor affecting soils properties. Then, it is a really important tool to predict the temperature reached in a soil after a wildfire. Currently, I am involve in a project to investigate what are the best post-fire treatments in our soils and how this treatments affects soil properties.

Controls of Soil Spatial Variability in a Dry Tropical Forest.

PubMed

Pulla, Sandeep; Riotte, Jean; Suresh, H S; Dattaraja, H S; Sukumar, Raman

2016-01-01

We examined the roles of lithology, topography, vegetation and fire in generating local-scale (<1 km2) soil spatial variability in a seasonally dry tropical forest (SDTF) in southern India. For this, we mapped soil (available nutrients, Al, total C, pH, moisture and texture in the top 10 cm), rock outcrops, topography, all native woody plants ≥1 cm diameter at breast height (DBH), and spatial variation in fire frequency (times burnt during the 17 years preceding soil sampling) in a permanent 50-ha plot. Unlike classic catenas, lower elevation soils had lesser moisture, plant-available Ca, Cu, Mn, Mg, Zn, B, clay and total C. The distribution of plant-available Ca, Cu, Mn and Mg appeared to largely be determined by the whole-rock chemical composition differences between amphibolites and hornblende-biotite gneisses. Amphibolites were associated with summit positions, while gneisses dominated lower elevations, an observation that concurs with other studies in the region which suggest that hillslope-scale topography has been shaped by differential weathering of lithologies. Neither NO3(-)-N nor NH4(+)-N was explained by the basal area of trees belonging to Fabaceae, a family associated with N-fixing species, and no long-term effects of fire on soil parameters were detected. Local-scale lithological variation is an important first-order control over soil variability at the hillslope scale in this SDTF, by both direct influence on nutrient stocks and indirect influence via control of local relief.

Controls of Soil Spatial Variability in a Dry Tropical Forest

PubMed Central

Pulla, Sandeep; Riotte, Jean; Suresh, H. S.; Dattaraja, H. S.; Sukumar, Raman

2016-01-01

We examined the roles of lithology, topography, vegetation and fire in generating local-scale (<1 km2) soil spatial variability in a seasonally dry tropical forest (SDTF) in southern India. For this, we mapped soil (available nutrients, Al, total C, pH, moisture and texture in the top 10cm), rock outcrops, topography, all native woody plants ≥1 cm diameter at breast height (DBH), and spatial variation in fire frequency (times burnt during the 17 years preceding soil sampling) in a permanent 50-ha plot. Unlike classic catenas, lower elevation soils had lesser moisture, plant-available Ca, Cu, Mn, Mg, Zn, B, clay and total C. The distribution of plant-available Ca, Cu, Mn and Mg appeared to largely be determined by the whole-rock chemical composition differences between amphibolites and hornblende-biotite gneisses. Amphibolites were associated with summit positions, while gneisses dominated lower elevations, an observation that concurs with other studies in the region which suggest that hillslope-scale topography has been shaped by differential weathering of lithologies. Neither NO3−-N nor NH4+-N was explained by the basal area of trees belonging to Fabaceae, a family associated with N-fixing species, and no long-term effects of fire on soil parameters were detected. Local-scale lithological variation is an important first-order control over soil variability at the hillslope scale in this SDTF, by both direct influence on nutrient stocks and indirect influence via control of local relief. PMID:27100088

The local impact of a coal-fired power plant on inorganic mercury and methyl-mercury distribution in rice (Oryza sativa L.).

PubMed

Xu, Xiaohang; Meng, Bo; Zhang, Chao; Feng, Xinbin; Gu, Chunhao; Guo, Jianyang; Bishop, Kevin; Xu, Zhidong; Zhang, Sensen; Qiu, Guangle

2017-04-01

Emission from coal-fired power plants is one of the major anthropogenic sources of mercury (Hg) in the environment, because emitted Hg can be quickly deposited nearby the source, attention is paid to the effects of coal-burning facilities on levels of toxic methyl-mercury (MeHg) in biota near such sources. Since rice is an agricultural crop that can bio-accumulate MeHg, the potential effects of a large Hg-emitting coal-fired power plant in Hunan Province, China on both inorganic Hg (Hg(II)) and MeHg distributions in rice was investigated. Relatively high MeHg (up to 3.8 μg kg -1 ) and Hg(II) (up to 22 μg kg -1 ) concentrations were observed in rice samples collected adjacent to the plant, suggesting a potential impact of Hg emission from the coal fired power plant on the accumulation of Hg in rice in the area. Concentrations of MeHg in rice were positively correlated with soil MeHg, soil S, and gaseous elemental Hg (GEM) in ambient air. Soil MeHg was the most important factor controlling MeHg concentrations in rice. The methylation of Hg in soils may be controlled by factors such as the chemical speciation of inorganic Hg, soil S, and ambient GEM. Copyright © 2016 Elsevier Ltd. All rights reserved.

Prolonged Effect of Severe Wildfires on Mercury and Other Volatiles in Forest Soils of the Lake Superior Region, USA

NASA Astrophysics Data System (ADS)

Cannon, W. F.; Woodruff, L. G.

2003-12-01

Soils in Isle Royale National Park, Michigan and Voyageurs National Park, Minnesota show spatial patterns of depletion of total Hg, organic C, Se, total S, P, and Pb within areas of severe, stand-replacing wildfires that burned in 1936, approximately 65 years prior to our current study. The fires burned during a regional drought, were of high severity, and likely consumed a high percentage of organic forest-floor material (O-horizon). A "fire factor" is defined by positive correlations among Hg, C, Se, S, P, and Pb. A factor score for this six-element grouping derived from factor analysis was assigned to each sample. The scores show a high spatial correlation with the footprint of the 1936 fires in both parks, particularly for A-horizon soils. Because many of these elements are volatile, and are highly correlated with soil organic matter, observed depletions likely represent instantaneous atmospheric release during combustion of O-horizon soils coupled with decades-long reduction of organic matter on the forest floor and near-surface soils. Nearly complete combustion of the modern O-horizon would release roughly 1 mg Hg/m2 from the forest floor. Decades-long disturbance resulting from destruction of mature forests and gradual regrowth following fire also play an important role in Hg cycling. Destruction of a mature forest results in decreased deposition of Hg from litterfall as well as throughfall, which contributes Hg by wash-off of dry deposited Hg from foliar surfaces. Hg in forest soils may follow a fire-dependent cycle in which sudden Hg loss during fire is followed by a period of continued Hg loss as evasion exceeds sequestration in the early stand-replacement stage, finally to resume gradual buildup in later stages of forest regrowth. In the Lake Superior region this cycle exceeds 65 years in duration and is of the same magnitude as the fire return interval for this region. Forests that are controlled by fire-induced cycles of stand replacement may also be in continuous cycles of Hg sequestration and emission. Fire history appears to be a major determinant in the amount of Hg stored in forest soils. Fire almost certainly releases Hg to the atmosphere as forest floor material is burned and thus contributes to atmospheric Hg loads. Fire also appears to cleanse burned areas of Hg both by the atmospheric release during combustion and longer-term release during post-fire forest reorganization. Fire cleansing appears to persist for decades after severe fires and may ameliorate Hg contamination of aquatic food webs by decreasing the soil Hg load of burned watersheds.

Interactive effects of fire, soil climate, and moss on CO2 fluxes in black spruce ecosystems of interior Alaska

USGS Publications Warehouse

O'Donnell, J. A.; Turetsky, M.R.; Harden, J.W.; Manies, K.L.; Pruett, L.E.; Shetler, G.; Neff, J.C.

2009-01-01

Fire is an important control on the carbon (C) balance of the boreal forest region. Here, we present findings from two complementary studies that examine how fire modifies soil organic matter properties, and how these modifications influence rates of decomposition and C exchange in black spruce (Picea mariana) ecosystems of interior Alaska. First, we used laboratory incubations to explore soil temperature, moisture, and vegetation effects on CO2 and DOC production rates in burned and unburned soils from three study regions in interior Alaska. Second, at one of the study regions used in the incubation experiments, we conducted intensive field measurements of net ecosystem exchange (NEE) and ecosystem respiration (ER) across an unreplicated factorial design of burning (2 year post-fire versus unburned sites) and drainage class (upland forest versus peatland sites). Our laboratory study showed that burning reduced the sensitivity of decomposition to increased temperature, most likely by inducing moisture or substrate quality limitations on decomposition rates. Burning also reduced the decomposability of Sphagnum-derived organic matter, increased the hydrophobicity of feather moss-derived organic matter, and increased the ratio of dissolved organic carbon (DOC) to total dissolved nitrogen (TDN) in both the upland and peatland sites. At the ecosystem scale, our field measurements indicate that the surface organic soil was generally wetter in burned than in unburned sites, whereas soil temperature was not different between the burned and unburned sites. Analysis of variance results showed that ER varied with soil drainage class but not by burn status, averaging 0.9 ?? 0.1 and 1.4 ?? 0.1 g C m-2d-1 in the upland and peatland sites, respectively. However, a more complex general linear model showed that ER was controlled by an interaction between soil temperature, moisture, and burn status, and in general was less variable over time in the burned than in the unburned sites. Together, findings from these studies across different spatial scales suggest that although fire can create some soil climate conditions more conducive to rapid decomposition, rates of C release from soils may be constrained following fire by changes in moisture and/or substrate quality that impede rates of decomposition. ?? 2008 Springer Science+Business Media, LLC.

Interactive effects of fire, soil climate, and moss on CO2 fluxes in black spruce ecosystems of interior Alaska

USGS Publications Warehouse

O'Donnell, Jonathan A.; Turetsky, Merritt R.; Harden, Jennifer W.; Manies, Kristen L.; Pruett, L.E.; Shetler, Gordon; Neff, Jason C.

2009-01-01

Fire is an important control on the carbon (C) balance of the boreal forest region. Here, we present findings from two complementary studies that examine how fire modifies soil organic matter properties, and how these modifications influence rates of decomposition and C exchange in black spruce (Picea mariana) ecosystems of interior Alaska. First, we used laboratory incubations to explore soil temperature, moisture, and vegetation effects on CO2 and DOC production rates in burned and unburned soils from three study regions in interior Alaska. Second, at one of the study regions used in the incubation experiments, we conducted intensive field measurements of net ecosystem exchange (NEE) and ecosystem respiration (ER) across an unreplicated factorial design of burning (2 year post-fire versus unburned sites) and drainage class (upland forest versus peatland sites). Our laboratory study showed that burning reduced the sensitivity of decomposition to increased temperature, most likely by inducing moisture or substrate quality limitations on decomposition rates. Burning also reduced the decomposability of Sphagnum-derived organic matter, increased the hydrophobicity of feather moss-derived organic matter, and increased the ratio of dissolved organic carbon (DOC) to total dissolved nitrogen (TDN) in both the upland and peatland sites. At the ecosystem scale, our field measurements indicate that the surface organic soil was generally wetter in burned than in unburned sites, whereas soil temperature was not different between the burned and unburned sites. Analysis of variance results showed that ER varied with soil drainage class but not by burn status, averaging 0.9 ± 0.1 and 1.4 ± 0.1 g C m−2 d−1 in the upland and peatland sites, respectively. However, a more complex general linear model showed that ER was controlled by an interaction between soil temperature, moisture, and burn status, and in general was less variable over time in the burned than in the unburned sites. Together, findings from these studies across different spatial scales suggest that although fire can create some soil climate conditions more conducive to rapid decomposition, rates of C release from soils may be constrained following fire by changes in moisture and/or substrate quality that impede rates of decomposition.

The viability of prescribed fire for mitigating the soil degradational impacts of wildfire

NASA Astrophysics Data System (ADS)

Shakesby, R. A.; Bento, C. P. M.; Ferreira, C. S. S.; Ferreira, A. J. D.; Stoof, C. R.; Urbanek, E.; Walsh, R. P. D.

2012-04-01

Prescribed (controlled) fire has become an important strategy primarily to limit the likelihood of more devastating wildfire. The considerable increase in wildfire activity in recent decades throughout the Mediterranean, and in Portugal in particular, has meant that this strategy has become increasingly popular despite inherent fears of people about fire of any sort. Despite many studies of the impact of wildfire on soil erosion and degradation, relatively little research has assessed impacts of prescribed fire on soil in Portugal or elsewhere in the Mediterranean. As part of the DESIRE research programme, this paper addresses this research gap by investigating hillslope-scale losses of soil, soil organic matter and selected nutrients before and after an experimental fire (representing a 'worst case-scenario' prescribed fire) in a shrub-vegetated catchment in central Portugal. Comparison is provided by post-fire monitoring of a nearby hillslope affected by a wildfire of moderate severity. Hillslope-scale measurements were carried out over c. 3 years using sediment fences with contributing areas of up to c. 0.5 ha. Eroded sediment was periodically removed from the fences both before and after the fire at intervals ranging from a few weeks to several months depending on rainfall characteristics and logistics. Erosion expressed as g/m2 and g/m2/mm of rainfall was determined. Figures for long-term (c. 10 years) erosion under unburnt conditions for this vegetation type were obtained from a small bounded plot and from sediment accumulating in a weir pool draining a sub-catchment within the prescribed-fire catchment. In addition, soil organic matter and selected nutrients, including K2O, P2O5 and Total N, were measured in the eroded sediment and in the pre-burn and post-burn in situ soil. The results indicate that both the wildfire and prescribed fire caused erosion that was orders of magnitude higher than for long-term plot-scale and hillslope-scale erosion recorded under unburnt conditions. Total post-fire erosion measured over 21 /2 years was relatively high for this worst case scenario prescribed fire even when compared with published results from smaller-scale plots monitored after wildfire elsewhere in the Mediterranean, which would be expected to be higher. Nevertheless, the post-fire hillslope-scale losses appear to have had a relatively low impact on the thin, stony, degraded soils. This is thought also to be the case following the wildfire, even though it caused somewhat higher erosion. Its other serious effects (damage to habitat and property, loss of life), however, mean that wildfire can never be viewed as acceptable, particularly where people live in close proximity to highly fire-prone terrain. The results support the viability of prescribed fire as a strategy for combating wildfire on shrub-vegetated terrain in this wet Mediterranean environment. This view of a low impact of prescribed fire on the terrain may be different where the stability of the soil is reduced by disturbance through ploughing, where soils are very thin or contain relatively few stones, or where fire is carried out too frequently.

Effect of prescribed fire on soil properties and N transformation in two vegetation types in South China.

PubMed

Wang, Faming; Li, Jian; Zou, Bi; Xu, Xin; Li, Zhian

2013-06-01

Prescribed fire is a common site preparation practice in forest management in southern China. However, the effect of fire on soil properties and N transformations is still poorly understood in this region. In this study, soil properties and N transformations in burned and unburned site of two vegetation types (Eucalyptus plantation and shrubland) were compared in rainy and dry seasons after 2 years' prescribed fire. Soil pH and soil NH4-N were all higher in the burned site compared to the unburned control. Furthermore, burned sites had 30-40 % lower of soil total phosphorus than conspecific unburned sites. There was no difference in soil organic matter, total N, soil exchangeable cations, available P or NO3-N. Nitrogen mineralization rate of 0-5 cm soil in the unburned site ranged from 8.24 to 11.6 mg N kg(-1) soil month(-1) in the rainy season, compared to a lower level of 4.82-5.25 mg N kg(-1) soil month(-1) in the burned sites. In contrast, 0-5 cm layer nitrification rate was overall 2.47 mg N kg(-1) soil month(-1) in the rainy season, and was not significantly affected by burning. The reduced understory vegetation coverage after burning may be responsible for the higher soil NH4-N in the burned site. This study highlights that a better understanding the effect of prescribed burning on soil nutrients cycling would provide a critical foundation for management decision and be beneficial to afforestation in southern China.

Assessment of temperature peaks reached during a wildfire. An approach using X-ray diffraction and differential thermal analysis

NASA Astrophysics Data System (ADS)

Jiménez-González, Marco A.; Jordán, Antonio; Zavala, Lorena M.; Mataix-Solera, Jorge; Bárcenas-Moreno, Gema; Jiménez-Morillo, Nicasio T.; Bellinfante, Nicolás

2014-05-01

1. INTRODUCTION Wildfires may induce important chemical and physical changes in soils, including changes in the soil composition, mineralogical changes, soil water repellency, aggregate stability or textural changes (Bodí et al., 2013; Granged et al., 2011a, 2011b, 2011c; Jordán et al., 2011, 2013; Mataix-Solera et al., 2011). As these changes usually occur after threshold temperature peaks, the assessment of these helps to explain many of the processes occurring during burning and in the postfire (Pereira et al., 2012, 2013; Shakesby, 2011). In July 2011, a wildfire burnt a pine forested area (50 ha) in Gorga (Alicante, SW Spain), approximately at 38° 44.3' N and 0° 20.7' W. Main soil type is Lithic Xerorthent developed from limestone. The study of mineralogical changes in soil after a wildfire should help to assess fire temperature peaks reached during burning. In order to study the impact of fire temperature on mineralogical changes and determine temperature peaks during burning, burnt soil plots under shrubland were randomly collected (0-5 cm deep). Control samples from adjacent unburnt areas were also collected for control. 2. METHODS Soil samples were ground using an agate mortar and then sieved (< 0.002mm) and analyzed by X-ray diffraction (XRD). XRD was conducted on a Bruker (model D8 advance A25) powder θ:θ diffractometer, which uses a Cu anticathode (40KV, 30mA), Ni filter in the diffracted bean and lineal detector. Powder samples were scanned from 3 to 70° 2θ, using a step size of 0.015° 2θ and a scan speed of 0.15° 2θ s-1. Mineralogical phase identification and quantification of minerals was carried out with XPowder. In order to study other possible reaction in burnt soil, unburnt soil samples were exposed to temperatures of 300, 500 and 700 °C in a Mufla furnace during 20 minutes. Unburnt control and treated samples were analyzed by differential thermal analysis (DTA) and thermogravimetric analysis (TG). 3. RESULTS Diffractograms show that the blixita peak, found in the control sample, disappears in the diffractograms of burnt samples. Other significant peaks (calcite, quartz and microcline, for example) do not show significant changes between control and burnt samples. After semiquantitative analysis, the proportion of calcite increased in burnt soil samples (76.3%, on average) respect to control unburnt soil samples (62.3%). This increase may be explained by calcium carbonate released by ash after combustion of organic matter. Consequently, quartz proportion decreased in burnt samples (10.7%, on average) respect to control samples (26.1%). After DTA analysis, a valley occurs between 400 and 700 °C in the control sample which is not present in 500 and 700 oC heated samples. This loss of energy is attributed to combustion of organic matter approximately between 400 and 500 °C, as well as thermal changes in iron oxides (which occurs approximately between 300 and 500 °C) and loss of structural water (>420 °C). In samples heated at 500 and 700 °C, these changes are not appreciated as they occurred during calcination. In the 300 °C heated sample, some of these changes partially occurred. Peaks observed approximately at 100 °C correspond to release of absorbed water. Peaks at 900 °C are a consequence of destruction of calcite. Finally a peak was observed at 680 °C in the control sample may be explained as a consequence of the destruction of blixite (Pb8(OH)2Cl4), which was present in control samples (1.1%) but not in burnt samples. This peak is probably masked in heated samples. REFERENCES Bodí, M.B., Muñoz-Santa, I., Armero, C., Doerr, S.H., Mataix-Solera, J., Cerdà, A. 2013. Spatial and temporal variations of water repellency and probability of its occurrence in calcareous Mediterranean rangeland soils affected by fires. Catena, 108, 14-25. Granged, A.J.P., Jordán, A., Zavala, L.M., Muñoz-Rojas, M., Mataix-Solera, J. 2011a. Short-term effects of experimental fire for a soil under eucalyptus forest (SE Australia). Geoderma, 167-168, 125-134. Granged, A.J.P., Zavala, L.M., Jordán, A., Bárcenas-Moreno, B. 2011b. Post-fire evolution of soil properties and vegetation cover in a Mediterranean heathland after experimental burning: A 3-year study. Geoderma, 164, 85-94. Granged, A.J.P., Jordán, A., Zavala, L.M., Bárcenas-Moreno, B. 2011c. Fire-induced changes in soil water repellency increased fingered flow and runoff rates following the 2004 Huelva wildfire. Hydrological Processes, 25, 1614-1629. Jordán, A., Zavala, L.M., Mataix-Solera, J., Nava, A.L., Alanís, N. 2011. Effect of fire severity on water repellency and aggregate stability on Mexican volcanic soils. Catena, 84, 136-147. Jordán A., Zavala, L.M., Mataix-Solera, J., Doerr, S.H. 2013. Soil water repellency: Origin, assessment and geomorphological consequences. Catena, 108, 1-5. Mataix-Solera, J., Cerdà, A., Arcenegui, V., Jordán, A., Zavala, L.M. 2011. Fire effects on soil aggregation: A review. Earth-Science Reviews, 109, 44-60. Pereira, P., Mierauskas, P., Úbeda, X., Mataix-Solera, J., Cerdà, A. 2012. Fire in Protected Areas - the Effect of Protection and Importance of Fire Management. Environmental Research, Engineering and Management, 59, 52-62. Pereira, P., Cerdà, A., Úbeda, X., Mataix-Solera, J., Martin, D., Jordán, A., Burguet, M. 2013. Spatial models for monitoring the spatio-temporal evolution of ashes after fire - a case study of a burnt grassland in Lithuania. Solid Earth 4, 153-165. Shakesby, R.A. 2011. Post-wildfire soil erosion in the Mediterranean: review and future research directions. Earth-Science Reviews, 71-100.

Soil respiration and root biomass responses to burning in calabrian pine (Pinus brutia) stands in Edirne, Turkey.

PubMed

Tufekcioglu, Aydin; Kucuk, Mehmet; Bilmis, Tuncay; Altun, Lokman; Yilmaz, Murat

2010-01-01

In this study soil properties and root biomass responses to prescribed fire were investigated in 25-30 year-old calabrian pine (Pinus brutia Ten.) stands in Edirne, Turkey. The stands were established by planting and were subjected to prescribed burning in July 2005. Soil respiration rates were determined every two months using the soda-lime method over a two-year period. Fine (> or = 2 mm diameter) and small root (> 2-5 mm diameter) biomass were sampled approximately bimonthly using the sequential coring method. Soil respiration rates in burned sites were significantly higher than in control sites during the summer season but there was no significant difference in the other seasons. Soil respiration rates were correlated significantly with soil moisture and soil temperature. Fine and small root biomass were significantly lower in burned sites than in control sites. Mean fine root biomass values were 3204 kg ha(-1) for burned and 3772 kg ha(-1) for control sites. Annual soil CO2 releases totaled 515 g Cm(-2) for burned and 418 g C m(-2) for control sites. Our results indicate that, depending on site conditions, fire could be used successfully as a tool in the management of calabrian pine stands in the study area.

Modeling of phosphorus fluxes produced by wild fires at watershed scales.

NASA Astrophysics Data System (ADS)

Matyjasik, M.; Hernandez, M.; Shaw, N.; Baker, M.; Fowles, M. T.; Cisney, T. A.; Jex, A. P.; Moisen, G.

2017-12-01

River runoff is one of the controlling processes in the terrestrial phosphorus cycle. Phosphorus is often a limiting factor in fresh water. One of the factors that has not been studied and modeled in detail is phosporus flux produced from forest wild fires. Phosphate released by weathering is quickly absorbed in soils. Forest wild fires expose barren soils to intensive erosion, thus releasing relatively large fluxes of phosphorus. Measurements from three control burn sites were used to correlate erosion with phosphorus fluxes. These results were used to model phosphorus fluxes from burned watersheds during a five year long period after fires occurred. Erosion in our model is simulated using a combination of two models: the WEPP (USDA Water Erosion Prediction Project) and the GeoWEPP (GIS-based Water Erosion Prediction Project). Erosion produced from forest disturbances is predicted for any watershed using hydrologic, soil, and meteorological data unique to the individual watersheds or individual slopes. The erosion results are modified for different textural soil classes and slope angles to model fluxes of phosphorus. The results of these models are calibrated using measured concentrations of phosphorus for three watersheds located in the Interior Western United States. The results will help the United States Forest Service manage phosporus fluxes in national forests.

Soils under fire: soils research and the Joint Fire Science Program.

Treesearch

Heather E. Erickson; Rachel White

2008-01-01

Soils are fundamental to a healthy and functioning ecosystem. Therefore, forest land managers can greatly benefit from a more thorough understanding of the ecological impacts of fire and fuel management activities on the vital services soils provide. We present a summary of new research on fire effects and soils made possible through the Joint Fire Science Program and...

Exploring functional relationships between post-fire soil water repellency, soil structure and physico-chemical properties

NASA Astrophysics Data System (ADS)

Quarfeld, Jamie; Brook, Anna; Keestra, Saskia; Wittenberg, Lea

2016-04-01

Soil water repellency (WR) and aggregate stability (AS) are two soil properties that are typically modified after burning and impose significant influence on subsequent hydrological and geomorphological dynamics. The response of AS and soil WR to fire depends upon how fire has influenced other key soil properties (e.g. soil OM, mineralogy). Meanwhile, routine thinning of trees and woody vegetation may alter soil properties (e.g. structure and porosity, wettability) by use of heavy machinery and species selection. The study area is situated along a north-facing slope of Mount Carmel national park (Israel). The selected sites are presented as a continuum of management intensity and fire histories. To date, the natural baseline of soil WR has yet to be thoroughly assessed and must be investigated alongside associated soil aggregating parameters in order to understand its overall impact. This study examines (i) the natural baseline of soil WR and physical properties compared to those of disturbed sites in the immediate (controlled burn) and long-term (10-years), and (ii) the interactions of soil properties with different control factors (management, surface cover, seasonal-temporal, burn temperature, soil organic carbon (OC) and mineralogy) in Mediterranean calcareous soils. Analysis of surface soil samples before and after destruction of WR by heating (200-600°C) was implemented using a combination of traditional methods and infrared (IR) spectroscopy. Management and surface cover type conditioned the wettability, soil structure and porosity of soils in the field, although this largely did not affect the heat-induced changes observed in the lab. A positive correlation was observed along an increasing temperature gradient, with relative maxima of MWD and BD reached by most soils at the threshold of 400-500°C. Preliminary analyses of soil OC (MIR) and mineralogical composition (VIS-NIR) support existing research regarding: (i) the importance of soil OC quality and composition in determining wettability rather than quantity, as evidenced both by the high variation observed in the field and the strong presence of aliphatic functional groups in the absence of WR; and (ii) commonly proposed mechanisms affecting soil aggregate properties - albeit with differing temperature thresholds and longer exposure times employed in this study. Namely, these mechanisms tend to involve: (i) soil OM and WR reduction at low to moderate temperatures, and (ii) thermal fusion of particles within moderate to high temperatures. Overall, results suggest a positive influence of management on soil properties as well as high soil resilience to moderate severity fire disturbance in the studied areas. However, the specific changes in soil OM and mineral composition that are responsible for destruction of WR and subsequent changes in AS remain poorly understood. Based on these results, a key next step within this study will entail a closer examination of OC ratios and their potential links with certain mineral species known to influence soil aggregation and soil WR. Noting the importance of soil OM-mineralogical interactions on run-off and erosion processes, results may contribute to better prediction of post-fire responses in the future and improve the ability to fine-tune site specific management approaches accordingly.

Land abandonment, fire recurrence and soil carbon content in the Macizo del Caroig, Eastern Spain

NASA Astrophysics Data System (ADS)

Cerdá, A.; González Peñaloza, F.; Santín, C.; Doerr, S. H.

2012-04-01

During the last 50 years two main forces have driven the fate of Mediterranean landscapes: land abandonment and forest fires (MacDonald et al., 2000; Moreira et al., 2001). Due to the economical changes suffered by the of the Mediterranean countries after the Second World War, the population migrated from the rural to the urban areas, and from South to North Europe. The land abandonment allowed the vegetation to recover and, as a consequence, an increase in forest fire took place. The soils of the abandoned land recovered the vegetation and litter layers, and consequently changes in soil properties have being found. One of these changes is the increase of soil carbon content, which is due both to vegetation recovery and to fire occurrence that increases the ash and pyrogenic carbon content in soils. Twenty plots were selected in the Macizo del Caroig in Eastern Spain on soils developed on limestone. The period of abandonment and the forest fires that had affected each plot were determined by interviews with the owners, farmers and shepherds. In addition, six (three + three) plots were selected as forest (no plough) and cultivated control plots. Each plot was sampled (10 random samples) and the organic carbon content determined. The results show that the cultivated plots have organic matter contents of 1.02 %, and the forest (Quercus ilex sp.) plots reach the highest value: 14.98 %. Within those we found values that range from 2.34 %, in the recently abandoned plots (10 year abandonment), to values of 8.23 % in the 50 year old abandoned fields.The results demonstrate that there is a recovery of the organic carbon in abandoned soils and that the forest fires do no affect this trend. The increase of soil organic matter after abandonment is a result of the recovery of vegetation(Debussche et al., 2001), which is the consequence of the end of the disturbance of forest that have affected the Mediterranean for millennia (Barbero et al., 1990). The colonization of the abandoned fields by the vegetation is very efficient (Ne'eman and Izhaki, 1996) and fire adapted species are the main types, which demonstrates that fire is part of the Mediterranean ecosystems (Pausas, 1999). The fire was not found here as a factor increasing the organic carbon in the abandoned soils, although it was found in a nearby area (Novara et al., 2011). This research confirms that the soil development in Mediterranean Type-Ecosystems (Cerdà et al., 2010) is being affected by land abandonment and fire (Doerr and Cerdà, 2005).

Increasing fire severity, alternate successional trajectories, and the carbon balance of Alaskan boreal forests

NASA Astrophysics Data System (ADS)

Mack, M. C.; Alexander, H. D.; Jean, M.; Melvin, A. M.; Johnstone, J. F.

2016-12-01

Climate-sensitive disturbances, such as wildfire, can feed back positively to climate warming via the carbon (C) cycle if C released by disturbance is not replaced over post-fire succession. In boreal forests, burning of carbon in deep organic soils is not only an important determinate of ecosystem element balance over the disturbance cycle, but also sets the conditions that control plant recruitment, species dominance and successional trajectory. Species dominance, in turn, has the potential to exert strong control over the plant-soil-microbial feedbacks that determine C and nutrient coupling, C storage, and ultimately, replacement of combusted C. We examined the consequences of increasing fire severity for C balance and C and nitrogen (N) coupling in Alaskan boreal forests. We estimated combustion losses in 90 black spruce (conifer) stands that burned in 2004. Over the next decade, we followed natural tree seedling establishment in these stands and used seedling species dominance identify conifer versus deciduous successional trajectories. We assembled data from 120 stands that varied in time after fire and successional trajectory, and estimated C and N dynamics across 150 years of post-fire succession for each trajectory. Conifer stands that burned with high severity transitioned to deciduous tree dominance after fire. These stands had smaller ecosystem pools of C and N before fire, lost a larger proportion of these pools during the fire, and began succession with smaller residual pools than stands that returned to conifer dominance after fire. Over secondary succession, deciduous stands accumulated about 10 times more carbon in aboveground biomass than conifer stands. Belowground biomass and soil carbon accumulation, by contrast, was about three times higher in the black spruce stands than in deciduous stands. As a result, net ecosystem C accumulation over the 100 year inter-fire interval was three times higher in deciduous stands than in coniferous stands. Nitrogen accumulation did not differ between the trajectories; high C:N ratio biomass accumulation in deciduous stands balanced low C:N ratio soil organic matter accumulation in conifer stands. The timing of N accumulation, however, differed substantially, supporting the idea that deciduous stands mine N from degrading permafrost after fire.

Experimental fire increases soil carbon dioxide efflux in a grassland long-term multifactor global change experiment.

PubMed

Strong, Aaron L; Johnson, Tera P; Chiariello, Nona R; Field, Christopher B

2017-05-01

Numerous studies have demonstrated that soil respiration rates increase under experimental warming, although the long-term, multiyear dynamics of this feedback are not well constrained. Less is known about the effects of single, punctuated events in combination with other longer-duration anthropogenic influences on the dynamics of soil carbon (C) loss. In 2012 and 2013, we assessed the effects of decadal-scale anthropogenic global change - warming, increased nitrogen (N) deposition, elevated carbon dioxide (CO 2 ), and increased precipitation - on soil respiration rates in an annual-dominated Mediterranean grassland. We also investigated how controlled fire and an artificial wet-up event, in combination with exposure to the longer-duration anthropogenic global change factors, influenced the dynamics of C cycling in this system. Decade-duration surface soil warming (1-2 °C) had no effect on soil respiration rates, while +N addition and elevated CO 2 concentrations increased growing-season soil CO 2 efflux rates by increasing annual aboveground net primary production (NPP) and belowground fine root production, respectively. Low-intensity experimental fire significantly elevated soil CO 2 efflux rates in the next growing season. Based on mixed-effects modeling and structural equation modeling, low-intensity fire increased growing-season soil respiration rates through a combination of three mechanisms: large increases in soil temperature (3-5 °C), significant increases in fine root production, and elevated aboveground NPP. Our study shows that in ecosystems where soil respiration has acclimated to moderate warming, further increases in soil temperature can stimulate greater soil CO 2 efflux. We also demonstrate that punctuated short-duration events such as fire can influence soil C dynamics with implications for both the parameterization of earth system models (ESMs) and the implementation of climate change mitigation policies that involve land-sector C accounting. © 2016 John Wiley & Sons Ltd.

Wildland fire in ecosystems: effects of fire on soils and water

Treesearch

Daniel G. Neary; Kevin C. Ryan; Leonard F. DeBano

2005-01-01

This state-of-knowledge review about the effects of fire on soils and water can assist land and fire managers with information on the physical, chemical, and biological effects of fire needed to successfully conduct ecosystem management, and effectively inform others about the role and impacts of wildland fire. Chapter topics include the soil resource, soil physical...

Effect of prescribed fire for tick control in California chaparral.

PubMed

Padgett, K A; Casher, L E; Stephens, S L; Lane, R S

2009-09-01

Prescribed fire was investigated as a method for controlling ixodid and argasid ticks in chaparral habitats in northern California. Two experimental and two adjacent control plots within a wildlife preserve were monitored for 1 yr postburn. Ticks were collected by flagging vegetation, by CO2-baited pitfall trap, and by live-trapping rodents. Twice as many rodents were caught at control sites compared with burn sites and no dusky-footed woodrats, Neotoma fuscipes Baird, were found in the treatment sites postburn. This species is known to be a reservoir of the agents of Lyme disease, Borrelia burgdorferi sensu stricto Johnson, Schmid, Hyde, Steigerwalt & Brenner, and human granulocytic anaplasmosis, Anaplasma phagocytophilum Dumler, Barbet, Bekker, Dasch, Palmer, Ray, Rikihisa, Rurangirwa. Six ixodid tick species were removed from rodents (Ixodes pacificus Cooley & Kohls, Ixodes jellisoni Cooley & Kohls, Ixodes spinipalpis Hadwen & Nuttall, Ixodes woodi Bishopp, Dermacentor occidentalis Marx, and Dermacentor parumapertus Neumann), two of which transmit bacterial zoonotic agents to people in the far-western United States. There was no decrease in number of ticks per animal trapped at either burn site compared with controls; in fact, the mean number of immature I. pacificus per rodent was significantly higher at one burn site than its control site. Soil refugia may protect ticks from fire-induced mortality; the argasid tick Ornithodoros coriaceus Koch, which lives in soil, was unaffected by the prescribed fire as were I. pacificus and D. occidentalis buried in packets 2.5 cm below ground. We conclude that although prescribed fires in chaparral habitats may diminish local rodent abundance, it does not decrease tick loads on rodents. Furthermore, burning chaparral does not result in a decreased abundance of adult ixodid ticks on vegetation and apparently does not affect argasid or ixodid ticks that are sheltered within soil refugia.

Litter and dead wood dynamics in ponderosa pine forests along a 160-year chronosequence.

PubMed

Hall, S A; Burke, I C; Hobbs, N T

2006-12-01

Disturbances such as fire play a key role in controlling ecosystem structure. In fire-prone forests, organic detritus comprises a large pool of carbon and can control the frequency and intensity of fire. The ponderosa pine forests of the Colorado Front Range, USA, where fire has been suppressed for a century, provide an ideal system for studying the long-term dynamics of detrital pools. Our objectives were (1) to quantify the long-term temporal dynamics of detrital pools; and (2) to determine to what extent present stand structure, topography, and soils constrain these dynamics. We collected data on downed dead wood, litter, duff (partially decomposed litter on the forest floor), stand structure, topographic position, and soils for 31 sites along a 160-year chronosequence. We developed a compartment model and parameterized it to describe the temporal trends in the detrital pools. We then developed four sets of statistical models, quantifying the hypothesized relationship between pool size and (1) stand structure, (2) topography, (3) soils variables, and (4) time since fire. We contrasted how much support each hypothesis had in the data using Akaike's Information Criterion (AIC). Time since fire explained 39-80% of the variability in dead wood of different size classes. Pool size increased to a peak as material killed by the fire fell, then decomposed rapidly to a minimum (61-85 years after fire for the different pools). It then increased, presumably as new detritus was produced by the regenerating stand. Litter was most strongly related to canopy cover (r2 = 77%), suggesting that litter fall, rather than decomposition, controls its dynamics. The temporal dynamics of duff were the hardest to predict. Detrital pool sizes were more strongly related to time since fire than to environmental variables. Woody debris peak-to-minimum time was 46-67 years, overlapping the range of historical fire return intervals (1 to > 100 years). Fires may therefore have burned under a wide range of fuel conditions, supporting the hypothesis that this region's fire regime was mixed severity.

Physiological responses of ponderosa pine in western Montana to thinning, prescribed fire and burning season.

PubMed

Sala, Anna; Peters, Gregory D; McIntyre, Lorna R; Harrington, Michael G

2005-03-01

Low-elevation ponderosa pine (Pinus ponderosa Dougl. ex. Laws.) forests of the northern Rocky Mountains historically experienced frequent low-intensity fires that maintained open uneven-aged stands. A century of fire exclusion has contributed to denser ponderosa pine forests with greater competition for resources, higher tree stress and greater risk of insect attack and stand-destroying fire. Active management intended to restore a semblance of the more sustainable historic stand structure and composition includes selective thinning and prescribed fire. However, little is known about the relative effects of these management practices on the physiological performance of ponderosa pine. We measured soil water and nitrogen availability, physiological performance and wood radial increment of second growth ponderosa pine trees at the Lick Creek Experimental Site in the Bitterroot National Forest, Montana, 8 and 9 years after the application of four treatments: thinning only; thinning followed by prescribed fire in the spring; thinning followed by prescribed fire in the fall; and untreated controls. Volumetric soil water content and resin capsule ammonium did not differ among treatments. Resin capsule nitrate in the control treatment was similar to that in all other treatments, although burned treatments had lower nitrate relative to the thinned-only treatment. Trees of similar size and canopy condition in the three thinned treatments (with and without fire) displayed higher leaf-area-based photosynthetic rate, stomatal conductance and mid-morning leaf water potential in June and July, and higher wood radial increment relative to trees in control units. Specific leaf area, mass-based leaf nitrogen content and carbon isotope discrimination did not vary among treatments. Our results suggest that, despite minimal differences in soil resource availability, trees in managed units where basal area was reduced had improved gas exchange and growth compared with trees in unmanaged units. Prescribed fire (either in the spring or in the fall) in addition to thinning, had no measurable effect on the mid-term physiological performance and wood growth of second growth ponderosa pine.

Effect of fire residues (ash and char) on microbial activity, respiration and methanogenesis in three subtropical wetland soils

NASA Astrophysics Data System (ADS)

Medvedeff, C.; Hogue, B.; Inglett, P.

2011-12-01

Prescribed fire is a common restoration and maintenance technique in the southern United States. Prescribed burns coupled with frequent natural fires in South Florida can have devastating effects on ecosystem function. To determine the effect fire residues have on carbon biogeochemical cycling litter material was obtained from two restored and one native marl wetland in Everglades National Park and manipulated in a laboratory setting to produce ash and vegetation derived char. Based on vegetation biomass removal pre and post fire (insitu) appropriate aliquots of each fire residue was added to experimental microcosms as a soil amendment. Soil enzymes (β-glucosidase, cellobiohydrolase, phosphatase, bis-phosphate and leucine amino peptidase), aerobic and anaerobic respiration (CO2) potentials, extractable C and methanogenesis were measured over a 25 day period. Regardless of site C enzymes responded to both amendments within 5 days of addition. Similarly amended soil contained more extractable carbon in the reference and one of the restored sites. In the restored sites ash and char inhibited methanogenesis, had no effect on anaerobic CO2 potentials, but stimulated aerobic respiration after ten days. In contrast, within the first ten days phosphatase enzyme activity was lower in the ash treatment when compared to the control treatment and stimulation of aerobic respiration was observed in both treatment soils. After ten days ash stimulated methanogenic processing while suppressing anaerobic CO2 production suggesting methanogens in this ecosystem may be dependant on usable carbon substrates derived from aerobic microbial processing. This study illustrates the variable response of C parameters to complete and incomplete combusted materials produced from both prescribed and natural fires with particular importance to fire adapted ecosystems.

Forest restoration treatments have subtle long-term effects on soil C and N cycling in mixed conifer forests.

PubMed

Ganzlin, Peter W; Gundale, Michael J; Becknell, Rachel E; Cleveland, Cory C

2016-07-01

Decades of fire suppression following extensive timber harvesting have left much of the forest in the intermountain western United States exceedingly dense, and forest restoration techniques (i.e., thinning and prescribed fire) are increasingly being used in an attempt to mitigate the effects of severe wildfire, to enhance tree growth and regeneration, and to stimulate soil nutrient cycling. While many of the short-term effects of forest restoration have been established, the long-term effects on soil biogeochemical and ecosystem processes are largely unknown. We assessed the effects of commonly used forest restoration treatments (thinning, burning, and thinning + burning) on nutrient cycling and other ecosystem processes 11 yr after restoration treatments were implemented in a ponderosa pine (Pinus ponderosa var. scopulorum)/Douglas fir (Pseudotsuga menziesii var. glauca) forest at the Lubrecht Fire and Fire Surrogates Study (FFS) site in western Montana, USA. Despite short-term (<3 yr) increases in soil inorganic nitrogen (N) pools and N cycling rates following prescribed fire, long-term soil N pools and N mineralization rates showed only subtle differences from untreated control plots. Similarly, despite a persistent positive correlation between fuels consumed in prescribed burns and several metrics of N cycling, variability in inorganic N pools decreased significantly since treatments were implemented, indicating a decline in N spatial heterogeneity through time. However, rates of net nitrification remain significantly higher in a thin + burn treatment relative to other treatments. Short-term declines in forest floor carbon (C) pools have persisted in the thin + burn treatment, but there were no significant long-term differences among treatments in extractable soil phosphorus (P). Finally, despite some short-term differences, long-term foliar nutrient concentrations, litter decomposition rates, and rates of free-living N fixation in the experimental plots were not different from control plots, suggesting nutrient cycles and ecosystem processes in temperate coniferous forests are resilient to disturbance following long periods of fire suppression. Overall, this study provides forest managers and policymakers valuable information showing that the effects of these commonly used restoration prescriptions on soil nutrient cycling are ephemeral and that use of repeated treatments (i.e., frequent fire) will be necessary to ensure continued restoration success. © 2016 by the Ecological Society of America.

The influence of fires on the properties of forest soils in the Amur River basin (the Norskii Reserve)

NASA Astrophysics Data System (ADS)

Tsibart, A. S.; Gennadiev, A. N.

2008-07-01

The influence of forest fires on the properties of taiga brown, gley taiga brown, and alluvial bog soils widespread in the area of the Norskii Reserve (the Amur River basin) was studied. During several years after the fire, the humus content increased, especially in the soils subjected to fires of high intensity. In the soils of steep slopes, the humus content decreased due to damage to the forest vegetation and activation of lateral runoff after the fire. As a rule, in the soils subjected to fire, the C ha-to-C fa ratio increased and correlated with the fire intensity. Some relationships between the forest fires and the acid-base properties of the soils were revealed. After the fires, the pH values often became higher. The stronger the fire, the higher the pH values. The stony soils differed from the other ones, since the reaction of their upper horizons turned out to be more acid after the fires. The analysis of the authors’ and literature data showed that the pyrogenic changes of some soil properties have been poorly studied and need further investigation, including their geographical aspects.

The effects of fire on greenhouse gas fluxes from mosses and lichen patches in the Yukon Kuskokwim Delta, AK.

NASA Astrophysics Data System (ADS)

Navarro-Perez, E.; Natali, S.; Schade, J. D.; Holmes, R. M.; Mann, P. J.

2017-12-01

Climate change has altered patterns of temperature, emissions of greenhouse gases and increased fire frequencies, especially in the Artic. Until recently, the Arctic has been a carbon (C) sink, but have begun releasing C in recent years, likely in response to warming temperatures, permafrost thaw and resulting changes in microbial processes. In addition, increases in fire frequency and intensity are changing vegetation patterns, particularly the relative importance of mosses and lichens. These changes alter soil temperatures, nutrient availability, and moisture, consequently affecting microbial processes and the release of greenhouse gases (GHG) such as N2O, CO2 and CH4. The objective of this research was to understand how recent fires in the Yukon-Kuskokwim River Delta in southwest Alaska are affecting the emission of GHGs from peat plateau soils. We hypothesized that the presence of mosses and lichen would change soil moisture and temperature, leading to changes in GHG production after fire. We also hypothesized that fire would increase soil nutrient availability, which would increase microbial process rates and GHG emissions. To test these hypotheses, we measured N2O, CH4 and CO2 fluxes from moss and lichen patches in three burned and unburned areas and collected soil cores for analyses of gravimetric soil moisture, carbon and nitrogen concentrations, and N mineralization rates. Soil temperatures were measured in the field with a thermocouple. Results demonstrated low but measurable CH4 emissions from all patches, suggesting peat plateaus in the YK Delta may be CH4 sources. In addition, CO2 emissions were higher in soils under lichen patches in burned areas than unburned controls. Finally, results suggest that burned areas have higher concentrations of extractable NH4 and NO3, and that increased N may be increasing soil respiration.

Integrating pH, substrate, and plant regrowth effects on soil nitrogen cycling after fire

NASA Astrophysics Data System (ADS)

Hanan, E. J.; Schimel, J.; Tague, C.; D'Antonio, C. M.

2014-12-01

Mediterranean-type ecosystems are structured by fire. In California chaparral, fires uncouple N production and consumption by enhancing nitrification and reducing plant uptake. NO3- that accumulates after fire is vulnerable to leaching. However, the extent to which fires decouple N fluxes can vary spatially and with timing of fire, and the specific mechanisms controlling N metabolism in recovering chaparral are not well understood. We combined empirical analysis and modeling in two chaparral watersheds to better understand how these systems recover from fire, and to explore their sensitivity to changing climate and fire regimes. To evaluate how pH, charcoal, and NH4+ supply influence N cycling, we measured mineralization and nitrification rates in chaparral soils that burned 1, 4, 20 and 40 years prior to sampling. We then experimentally adjusted pH, charcoal, and NH4+ concentrations for all soils in a factorial design, and incubated them for 8 weeks. Each week, we measured respiration, exchangeable NH4+ and NO3- content, nitrification potential, microbial biomass, and pH. Then to project the effects of altered precipitation patterns and fire timing on nitrogen dynamics and recovery, we used the hydro-biogeochemical model RHESSys. Fires were imposed at the beginning and end of the growing season under various climates. NO3- production was highest in soils collected from the most recently burned sites. Also, NO3- concentrations increased over the course of incubation in soils from all sites, especially at high pH, and with NH4+ addition. Charcoal slightly augmented the effects of elevated pH and NH4+ on NO3- production iduring the early stages of incubation in 1 and 4-year old sites, while it slightly dampened their effects by week 8. However, in 20 and 40-year old sites, charcoal had no effect. Overall, nitrification was most powerfully constrained by NH4+ supply. However, increases in pH that occur after fire may enhance nitrification rates when substrate is available. Also, charcoal might enhance N cycling immediately after fire, perhaps by supplying C to microbes, but impacts are short-lived. Modeling results suggest that soil acidity and rapid plant recovery reduce leaching. However, during drought and temperature extremes nutrients pools recover more slowly when fires occur prior to the hot, dry summer.

Microbial contents of soil from fire pits

NASA Astrophysics Data System (ADS)

Moon, K.; Esparza, V.; de Sandre, J.; Cheney, S.; Anderson, A.; White, M. A.

2006-12-01

Forest fires generate polycylic aromatic hydrocarbons (PAHs) that can lead to carcinogenic compounds, which are potential health risks. PAHs can be degraded to water and carbon dioxide by certain soil microbes. Thus, during participation in a NASA-funded summer research experience at Utah State University, our high school student team sampled soils from a month-old fire pit in which plant materials had been burnt. We detected in soil samples, from surface, 10 and 20 cm depths, microbes that would grow on a defined minimal medium source. Other microbes were cultured from the roots of plants that had established at the fire pit. A diversity of microbes was present in all samples based on visible differences in cell shape and color. It was surprising that the surface ash, although exposed to sunlight over the month interval, had culturable colonies. Many of these culturable bacteria were pigmented perhaps as a protection against UV radiation from the sun. We searched for genes in the microbes that encoded enzymes called dioxygenases that in other bacteria are involved in degradation of PAHs. This test involved using polymerase chain reactions to detect the genes. PCR products were found in two of the fifteen isolates tested although their sizes differed from the control gene product from a PAH-degrading mycobacterium isolate. These results suggest that the soils did contain microbes with the possible potential to alter the PAH compounds generated from vegetation fires. Our findings serve as a starting point for future studies looking at recovery and remediation of fired acreages.

Predicted effects of prescribed burning and harvesting on forest recovery and sustainability in southwest Georgia, USA.

PubMed

Garten, Charles T

2006-12-01

A model-based analysis of the effect of prescribed burning and forest thinning or clear-cutting on stand recovery and sustainability was conducted at Fort Benning, GA, in the southeastern USA. Two experiments were performed with the model. In the first experiment, forest recovery from degraded soils was predicted for 100 years with or without prescribed burning. In the second experiment simulations began with 100 years of predicted stand growth, then forest sustainability was predicted for an additional 100 years under different combinations of prescribed burning and forest harvesting. Three levels of fire intensity (low, medium, and high), that corresponded to 17%, 33%, and 50% consumption of the forest floor C stock by fire, were evaluated at 1-, 2-, and 3-year fire return intervals. Relative to the control (no fire), prescribed burning with a 2- or 3-year return interval caused only a small reduction in predicted steady state soil C stocks (< or =25%) and had no effect on steady state tree wood biomass, regardless of fire intensity. Annual high intensity burns did adversely impact forest recovery and sustainability (after harvesting) on less sandy soils, but not on more sandy soils that had greater N availability. Higher intensity and frequency of ground fires increased the chance that tree biomass would not return to pre-harvest levels. Soil N limitation was indicated as the cause of unsustainable forests when prescribed burns were too frequent or too intense to permit stand recovery.

Landscape effects of wildfire on permafrost distribution in interior Alaska derived from remote sensing

USGS Publications Warehouse

Brown, Dana R. N.; Jorgenson, M. Torre; Kielland, Knut; Verbyla, David L.; Prakash, Anupma; Koch, Joshua C.

2016-01-01

Climate change coupled with an intensifying wildfire regime is becoming an important driver of permafrost loss and ecosystem change in the northern boreal forest. There is a growing need to understand the effects of fire on the spatial distribution of permafrost and its associated ecological consequences. We focus on the effects of fire a decade after disturbance in a rocky upland landscape in the interior Alaskan boreal forest. Our main objectives were to (1) map near-surface permafrost distribution and drainage classes and (2) analyze the controls over landscape-scale patterns of post-fire permafrost degradation. Relationships among remote sensing variables and field-based data on soil properties (temperature, moisture, organic layer thickness) and vegetation (plant community composition) were analyzed using correlation, regression, and ordination analyses. The remote sensing data we considered included spectral indices from optical datasets (Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and Landsat 8 Operational Land Imager (OLI)), the principal components of a time series of radar backscatter (Advanced Land Observing Satellite—Phased Array type L-band Synthetic Aperture Radar (ALOS-PALSAR)), and topographic variables from a Light Detection and Ranging (LiDAR)-derived digital elevation model (DEM). We found strong empirical relationships between the normalized difference infrared index (NDII) and post-fire vegetation, soil moisture, and soil temperature, enabling us to indirectly map permafrost status and drainage class using regression-based models. The thickness of the insulating surface organic layer after fire, a measure of burn severity, was an important control over the extent of permafrost degradation. According to our classifications, 90% of the area considered to have experienced high severity burn (using the difference normalized burn ratio (dNBR)) lacked permafrost after fire. Permafrost thaw, in turn, likely increased drainage and resulted in drier surface soils. Burn severity also influenced plant community composition, which was tightly linked to soil temperature and moisture. Overall, interactions between burn severity, topography, and vegetation appear to control the distribution of near-surface permafrost and associated drainage conditions after disturbance.

Fire-induced pine woodland to shrubland transitions in Southern Europe may promote shifts in soil fertility.

PubMed

Mayor, A G; Valdecantos, A; Vallejo, V R; Keizer, J J; Bloem, J; Baeza, J; González-Pelayo, O; Machado, A I; de Ruiter, P C

2016-12-15

Since the mid of the last century, fire recurrence has increased in the Iberian Peninsula and in the overall Mediterranean basin due to changes in land use and climate. The warmer and drier climate projected for this region will further increase the risk of wildfire occurrence and recurrence. Although the impact of wildfires on soil nutrient content in this region has been extensively studied, still few works have assessed this impact on the basis of fire recurrence. This study assesses the changes in soil organic C and nutrient status of mineral soils in two Southern European areas, Várzea (Northern Portugal) and Valencia (Eastern Spain), affected by different levels of fire recurrence and where short fire intervals have promoted a transition from pine woodlands to shrublands. At the short-term (<1year), the amount of soil organic matter was higher in burned than in unburned soils while its quality (represented as labile to total organic matter) was actually lower. In any case, total and labile soil organic matter showed decreasing trends with increasing fire recurrence (one to four fires). At the long-term (>5years), a decline in overall soil fertility with fire recurrence was also observed, with a drop between pine woodlands (one fire) and shrublands (two and three fires), particularly in the soil microsites between shrubs. Our results suggest that the current trend of increasing fire recurrence in Southern Europe may result in losses or alterations of soil organic matter, particularly when fire promotes a transition from pine woodland to shrubland. The results also point to labile organic matter fractions in the intershrub spaces as potential early warning indicators for shifts in soil fertility in response to fire recurrence. Copyright © 2016 Elsevier B.V. All rights reserved.

Does temperature of charcoal creation affect subsequent mineralization of soil carbon and nitrogen?

NASA Astrophysics Data System (ADS)

Pelletier-Bergeron, S.; Bradley, R.; Munson, A. D.

2012-04-01

Forest fire is the most common form of natural disturbance of boreal forest ecosystems and has primordial influence on successional processes. This may be due in part to the pre-disturbance vegetation development stage and species composition, but these successional pathways could also vary with differences in fire behavior and consequently in fire intensity, defined as the energy released during various phases of a fire. Fire intensity may also affect soil C and N cycling by affecting the quality of the charcoal that is produced. For example, the porosity of coal tends to increase with increasing temperature at which it is produced Higher porosity would logically increase the surface area to which dissolved soil molecules, such as tannins and other phenolics, may be adsorbed. We report on a microcosm study in which mineral and organic soils were jointly incubated for eight weeks with a full factorial array of treatments that included the addition of Kalmia tannins, protein, and wood charcoal produced at five different temperatures. A fourth experimental factor comprised the physical arrangement of the material (stratified vs. mixed), designed to simulate the effect of soil scarification after fire and salvage harvest. We examined the effects of these treatments on soil C and N mineralisation and soil microbial biomass. The furnace temperature at which the charcoal was produced had a significant effect on its physico-chemical properties; increasing furnace temperatures corresponded to a significant increase in % C (P<0.001), and a significant decrease in %O (P<0.001) and %H (P<0.001). Temperature also had significant impacts on microporosity (surface area and volume). Temperature of production had no effect (P=0.1355) on soil microbial biomass. We observed a linear decreasing trend (P<0.001) in qCO2 with increasing temperature of production, which was mainly reflected in a decline in basal respiration. Finally, we found a significant interaction (P=0.010) between temperature of charcoal production x soil mixing in controlling post incubation NH4+ concentrations. We discuss the results in relation to potential implications for changing fire regime and C and N cycles.

BOREAS TGB-5 CO2, CH4 and CO Chamber Flux Data Over the NSA

NASA Technical Reports Server (NTRS)

Burke, Roger; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor); Zepp, Richard

2000-01-01

The BOReal Ecosystem-Atmosphere Study Trace Gas Biogeochemistry (BOREAS TGB-5) team collected a variety of trace gas concentration and flux measurements at several NSA sites. This data set contains carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO) chamber flux measurements conducted in 1994 at upland forest sites that experienced stand-replacement fires. These measurements were acquired to understand the impact of fires on soil biogeochemistry and related changes in trace gas exchange in boreal forest soils. Relevant ancillary data, including data concerning the soil temperature, solar irradiance, and information from nearby un-burned control sites, are included to provide a basis for modeling the regional impacts of fire and climate changes on trace gas biogeochemistry. The data are provided in tabular ASCII files.

Tools and perspectives for a unified approach to understanding microbial ecology in the critical zone

NASA Astrophysics Data System (ADS)

Gallery, R. E.; Aronson, E. L.; Fairbanks, D.; Murphy, M. A.; Rich, V. I.; Hart, S. C.

2015-12-01

Microbial communities that control nutrient transformation and storage in ecosystems are themselves influenced by landscape topography and vegetative cover. Globally, disturbances such as fires and insect outbreaks are increasing in frequency and severity with enormous impacts on global carbon cycling. The resiliency of soil microbial communities to these heterogeneous disturbances determines rates of nutrient transformations as well as ecosystem structure and recovery. Natural and anthropogenic disturbances are a common thread throughout Critical Zone Observatories and ecosystems in general. Using the 2013 Thompson Ridge Fire in the Jemez River Basin CZO as a case study, we examine the effect of a wildfire disturbance regime on successional changes in soil microbiota and ecosystem fluxes across a landscape with high topographic variation. We find that, layered over the topographic controls of hotspots of biogeochemical activity, fire alters organic substrate quality, microbial biomass, community structure, and activity. For example, fire increases soil pH, which is commonly found as an explanatory variable describing bacterial community structure. Soil microbes excrete exoenzymes to decompose polymers and acquire nutrients, and these activities can indicate changing microbial function or soil quality. In these mixed conifer forests, we find shifts from carbon to nitrogen-dominated exoenzyme activities in burned forests with alkaline soils, suggesting shifts of microbial taxa and function that correspond with recovering soil microbial biomass. More generally we ask - what combination of tools and perspectives is needed to fully understand soil microbial ecology and biogeochemistry of the critical zone? Results from an NSF Science Across Virtual Institutes (SAVI) CZO Network Biogeochemistry Workshop highlight the importance of incorporating a standard suite of microbial activity and community assays along with soil biogeochemical and flux measurements to enable comparisons across the broader CZO network. These characterizations would provide regional microbial function and biodiversity data in a standardized framework that can be used to enable more effective management and valuation of critical zone services and inform projections under global change scenarios.

The Role of Low-severity Fire and Thermal Alteration of Soil Organic Matter in Carbon Preservation and GHG Flux From Global Peatlands

NASA Astrophysics Data System (ADS)

Flanagan, N. E.; Wang, H.; Hodgkins, S. B.; Richardson, C. J.

2017-12-01

Many global peatlands are dominated by fire-adapted plant communities and are subject to frequent wildfires with return intervals ranging between 3 to 100 years. Wildfires in peatlands are typically low-severity events that occur in winter and spring when vegetation is desiccated and soil moisture content is high. As a result, most wildfires consume aboveground fuels in a matter of minutes without igniting the nearly saturated peat. In such fires, surface soil layers are subjected to flash heating with a rapid loss of soil moisture but little loss of soil organic matter (SOM). Such fires have the potential to alter the chemical structure of SOM, even in the absence of combustion, through Maillard's Reaction and similar chemical processes, and through structural changes that protect SOM from decomposition. This study examines the effects of low-intensity surface fires on the recalcitrance of SOM from fire-adapted communities located in subtropical, temperate and sub-boreal peatlands. In addition, soil from a non-fire-adapted Peruvian palm peatland was examined for response to thermal alteration. The timing and temperatures of low-intensity fires were measured in the field during prescribed burns and replicated in simulated fires. The effects of fire on the chemical structure of SOM were examined with FTIR, SEM and XPS. Burned and unburned peat replicates were incubated at three temperatures (5oC, 15oC, 25oC) in controlled chambers for more than six months. Burned replicates initially showed higher CO2, CH4 and NO2 emissions. Yet, within four weeks emissions from the burned replicates dropped below those of unburned replicates and remained significantly lower (10-50%) for the duration of the experiment. In addition, thermal alteration significantly reduced the temperature sensitivity (Q10) of thermally altered peat. After accounting for small initial losses of organic matter (<10 %) during the fire simulations, thermal alteration of SOM resulted in a net long-term reduction in carbon losses to microbial respiration. Such thermal alteration of SOM might be an underestimated factor influencing carbon accretion in frequently burned peatlands and could be globally relevant if climate change increases fire frequency in boreal peatlands.

Effects of rock fragments on water dynamics in a fire-affected soil

NASA Astrophysics Data System (ADS)

Gordillo-Rivero, Ángel J.; García-Moreno, Jorge; Jordán, Antonio; Zavala, Lorena M.

2014-05-01

Rock fragments (RF) are common in the surface of Mediterranean semiarid soils, and have important effects on the soil physical (bulk density and porosity) and hydrological processes (infiltration, evaporation, splash erosion and runoff generation) (Poesen and Lavee, 1994; Rieke-Zapp et al., 2007). In some cases, RFs in Mediterranean areas have been shown to protect bare soils from erosion risk (Cerdà, 2001; Martínez-Zavala, Jordán, 2008; Zavala et al., 2010). Some of these effects are much more relevant when vegetation cover is low or has been reduced after land use change or other causes, as forest fires. Although very few studies exist, the interest on the hydrological effects of RFs in burned areas is increasing recently. After a forest fire, RFs may contribute significantly to soil recovery. In this research we have studied the effect of surface and embedded RFs on soil water control, infiltration and evaporation in calcareous fire-affected soils from a Mediterranean area (SW Spain). For this study, we selected an area with soils derived from limestone under holm oak forest, recently affected by a moderate severity forest fire. The proportion of RF cover showed a significant positive relation with soil water-holding capacity and infiltration rates, although infiltration rate reduced significantly when RF cover increased above a certain threshold. Soil evaporation rate decreased with increasing volumetric content of RFs and became stable with RF contents approximately above 30%. Evaporation also decreased with increasing RF cover. When RF cover increased above 50%, no significant differences were observed between burned and control vegetated plots. REFERENCES Poesen, J., Lavee, H. 1994. Rock fragments in top soils: significance and processes. Catena Supplement 23, 1-28. Cerdà, A. 2001. Effect of rock fragment cover on soil infiltration, interrill runoff and erosion. European Journal of Soil Science 52, 59-68. DOI: 10.1046/j.1365-2389.2001.00354.x. Rieke-Zapp, D., Poesen, J., Nearing, M.A. 2007. Effects of rock fragments incorporated in the soil matrix on concentrated flow hydraulics and erosion. Earth Surface Processes and Landforms 32, 1063-1076. Martínez-Zavala, L., Jordán, A., 2008. Effect of rock fragment cover on interrill soil erosion from bare soils in Western Andalusia, Spain. Soil Use and Management 24, 108, 117. DOI: 10.1111/j.1475-2743.2007.00139.x. Zavala, L.M., Jordán, A., Bellinfante, N., Gil, J. 2010. Relationships between rock fragment cover and soil hydrological response in a Mediterranean environment, Soil Science and Plant Nutrition 56, 95-104. DOI: 10.1111/j.1747-0765.2009.00429.x.

Iron in the Fire: Searching for Fire's Magnetic Fingerprint using Controlled Heating Experiments, High-Resolution FORCs, IRM Coercivity Spectra, and Low-Temperature Remanence Experiments

NASA Astrophysics Data System (ADS)

Lippert, P. C.; Reiners, P. W.

2014-12-01

Evidence for recent climate-wildfire linkages underscores the need for better understanding of relationships between wildfire and major climate shifts in Earth history, which in turn offers the potential for prognoses for wildfire and human adaptations to it. In particular, what are the links between seasonality and wildfire frequency and severity, and what are the feedbacks between wildfire, landscape evolution, and biogeochemical cycles, particularly the carbon and iron cycles? A key first step in addressing these questions is recovering well-described wildfire records from a variety of paleolandscapes and paleoclimate regimes. Although charcoal and organic biomarkers are commonly used indicators of fire, taphonomic processes and time-consuming analytical preparations often preclude their routine use in some environments and in high-stratigraphic resolution paleowildfire surveying. The phenomenological relationship between fire and magnetic susceptibility can make it a useful surveying tool, but increased magnetic susceptibility in sediments is not unique to fire, and thus limits its diagnostic power. Here we utilize component-specific rock magnetic methods and analytical techniques to identify the rock magnetic fingerprint of wildfire. We use a custom-designed air furnace, a series of iron-free laboratory soils, natural saprolites and soils, and fuels from Arizona Ponderosa pine forests and grasslands to simulate wildfire in a controlled and monitored environment. Soil-ash residues and soil and fuel controls were then characterized using First Order Reversal Curve (FORC) patterns, DC backfield IRM coercivity spectra, low-temperature SIRM demagnetization behavior, and low-temperature cycling of room-temperature SIRM behavior. We will complement these magnetic analyses with high-resolution TEM of magnetic extracts. Here we summarize the systematic changes to sediment magnetism as pyrolitized organic matter is incorporated into artificial and natural soils. These observations help us elucidate the processes and sources responsible for increases in magnetic susceptibility observed in natural burned soils, as well as identify a unique rock magnetic fingerprint for natural wildfire that has the potential to be preserved in sedimentary sequences in the geological record.

Effects of forest fire on soil nutrients in Turkish pine (Pinus brutia, Ten) ecosystems.

PubMed

Yildiz, Oktay; Esen, Derya; Sarginci, Murat; Toprak, Bulent

2010-01-01

Fire is a long-standing and poorly understood component of the Mediterranean forestlands in Turkey. Fire can alter plant composition, destroy biomass, alter soil physical and chemical properties and reduce soil nutrient pools. However fire can also promote productivity of certain ecosystems by mineralizing soil nutrients and promoting fast growing nitrogen fixing plant species. Fire effects on soils and ecosystems in Turkey and Mediterranean regions are not well understood. This study uses a retrospective space-for-time substitution to study soil macro-nutrient changes on sites which were burned at different times during the last 8 years. The study sites are in the Fethiye Forest Management Directorate in the western Mediterranean Sea region of Turkey. Our samples show 40% less Soil C, and cation exchange capacity (CEC) at 0-20 cm soil depth two weeks after the fire. Soil C and CEC appear to recover to pre-fire level in one year. Concentrations of Mg were significantly lower on new-burn sites, but returned to pre-fire levels in one year. Total soil N concentrations one and two years after fire were 90% higher than other sites, and total P was 9 times higher on new-burn site than averages from other sites. Some implications of these results for forest managers are discussed.

The influence of fire history, plant species and post-fire management on soil water repellency in a Mediterranean catchment: the Mount Carmel range, Israel

NASA Astrophysics Data System (ADS)

Keesstra, Saskia; Wittenberg, Lea; Maroulis, Jerry; Malkinson, Dan; Cerdà, Artemi; Pereira, Paulo

2016-04-01

Fire is a key factor impacting soil hydrology in many Mediterranean catchments. Soil water repellency (SWR) can stimulate land degradation processes by reducing the affinity of soil and water thereby triggering a reduction in soil fertility and increasing soil and water losses (. The effects of two consequent fires (1989 and 2005) on SWR were assessed in the Carmel Mountains, Israel. Fire history, plant recovery and post-fire management were investigated as determining factors in a time dependent system. SWR was highest in the >50 years unburnt plots, where soil under Pinus halepensis is most hydrophobic. In the most disturbed soils (twice burnt), many sites have a low to absent SWR even if the soil is very dry. The dynamics and fluctuations in SWR differ in magnitude under different plant species. The areas treated with CC (chipping of charred trees) showed a much higher SWR than areas left untreated. From these insights, a conceptual model of the reaction of SWR on multiple fires was developed. KEYWORDS: Soil water repellency, WDPT, Wildfires, Vegetation recovery, post-fire management, Mediterranean.

Index for characterizing post-fire soil environments in temperate coniferous forests

USGS Publications Warehouse

Jain, Theresa B.; Pilliod, David S.; Graham, Russell T.; Lentile, Leigh B.; Sandquist, Jonathan E.

2012-01-01

Many scientists and managers have an interest in describing the environment following a fire to understand the effects on soil productivity, vegetation growth, and wildlife habitat, but little research has focused on the scientific rationale for classifying the post-fire environment. We developed an empirically-grounded soil post-fire index (PFI) based on available science and ecological thresholds. Using over 50 literature sources, we identified a minimum of five broad categories of post-fire outcomes: (a) unburned, (b) abundant surface organic matter ( > 85% surface organic matter), (c) moderate amount of surface organic matter ( ≥ 40 through 85%), (d) small amounts of surface organic matter ( < 40%), and (e) absence of surface organic matter (no organic matter left). We then subdivided each broad category on the basis of post-fire mineral soil colors providing a more fine-tuned post-fire soil index. We related each PFI category to characteristics such as soil temperature and duration of heating during fire, and physical, chemical, and biological responses. Classifying or describing post-fire soil conditions consistently will improve interpretations of fire effects research and facilitate communication of potential responses or outcomes (e.g., erosion potential) from fires of varying severities.

Soil, fire, water, and wind: how the elements conspire in the forest context

Treesearch

Ralph E.J. Boerner

2006-01-01

Reviews our current understanding of the impact of fires typical of eastern oak forests on soil properties, soil organisms, and water quality. Most oak ecosystem fires are dormant-season fires whose intensity falls at the low end of the range of wildland fires. Direct heating of the mineral soil generally is minor except where accumulations of woody debris smolder for...

Fire effects on temperate forest soil C and N storage.

PubMed

Nave, Lucas E; Vance, Eric D; Swanston, Christopher W; Curtis, Peter S

2011-06-01

Temperate forest soils store globally significant amounts of carbon (C) and nitrogen (N). Understanding how soil pools of these two elements change in response to disturbance and management is critical to maintaining ecosystem services such as forest productivity, greenhouse gas mitigation, and water resource protection. Fire is one of the principal disturbances acting on forest soil C and N storage and is also the subject of enormous management efforts. In the present article, we use meta-analysis to quantify fire effects on temperate forest soil C and N storage. Across a combined total of 468 soil C and N response ratios from 57 publications (concentrations and pool sizes), fire had significant overall effects on soil C (-26%) and soil N (-22%). The impacts of fire on forest floors were significantly different from its effects on mineral soils. Fires reduced forest floor C and N storage (pool sizes only) by an average of 59% and 50%, respectively, but the concentrations of these two elements did not change. Prescribed fires caused smaller reductions in forest floor C and N storage (-46% and -35%) than wildfires (-67% and -69%), and the presence of hardwoods also mitigated fire impacts. Burned forest floors recovered their C and N pools in an average of 128 and 103 years, respectively. Among mineral soils, there were no significant changes in C or N storage, but C and N concentrations declined significantly (-11% and -12%, respectively). Mineral soil C and N concentrations were significantly affected by fire type, with no change following prescribed burns, but significant reductions in response to wildfires. Geographic variation in fire effects on mineral soil C and N storage underscores the need for region-specific fire management plans, and the role of fire type in mediating C and N shifts (especially in the forest floor) indicates that averting wildfires through prescribed burning is desirable from a soils perspective.

Quantifying the effects of wildfire on changes in soil properties by surface burning of soils from the Boulder Creek Critical Zone Observatory

USGS Publications Warehouse

Wieting, Celeste; Ebel, Brian A.; Singha, Kamini

2017-01-01

Study regionThis study used intact soil cores collected at the Boulder Creek Critical Zone Observatory near Boulder, Colorado, USA to explore fire impacts on soil properties.Study focusThree soil scenarios were considered: unburned control soils, and low- and high-temperature burned soils. We explored simulated fire impacts on field-saturated hydraulic conductivity, dry bulk density, total organic carbon, and infiltration processes during rainfall simulations.New hydrological insights for the regionSoils burned to high temperatures became more homogeneous with depth with respect to total organic carbon and bulk density, suggesting reductions in near-surface porosity. Organic matter decreased significantly with increasing soil temperature. Tension infiltration experiments suggested a decrease in infiltration rates from unburned to low-temperature burned soils, and an increase in infiltration rates in high-temperature burned soils. Non-parametric statistical tests showed that field-saturated hydraulic conductivity similarly decreased from unburned to low-temperature burned soils, and then increased with high-temperature burned soils. We interpret these changes result from the combustion of surface and near-surface organic materials, enabling water to infiltrate directly into soil instead of being stored in the litter and duff layer at the surface. Together, these results indicate that fire-induced changes in soil properties from low temperatures were not as drastic as high temperatures, but that reductions in surface soil water repellency in high temperatures may increase infiltration relative to low temperatures.

Timing of fire relative to seed development controls availability of non-serotinous aerial seed banks

Treesearch

S.T. Michaletz; E.A. Johnson; W.E. Mell; D.F. Greene

2012-01-01

The existence of non-serotinous, non-sprouting species in fire regimes where serotiny confers an adaptive advantage is puzzling, particularly when these species recruit poorly from soil seed banks or from burn edges. In this paper, white spruce (Picea glauca (Moench) Voss) was used to show that the timing of fire relative to seed development can...

Temporal effects of post-fire check dam construction on soil functionality in SE Spain.

PubMed

González-Romero, J; Lucas-Borja, M E; Plaza-Álvarez, P A; Sagra, J; Moya, D; De Las Heras, J

2018-06-09

Wildfire has historically been an alteration factor in Mediterranean basins. Despite Mediterranean ecosystems' high resilience, wildfire accelerates erosion and degradation processes, and also affects soil functionality by affecting nutrient cycles and soil structure. In semi-arid Mediterranean basins, check dams are usually built in gullies and channels after fire as a measure against soil erosion. Although check dams have proven efficient action to reduce erosion rates, studies about how they affect soil functionality are lacking. Our approach focuses on how soil functionality, defined as a combination of physico-chemical and biological indicators, is locally affected by check dam construction and the evolution of this effect over time. Soils were sampled in eight check dams in two semi-arid areas at SE Spain, which were affected by wildfire in 2012 and 2016. The study findings reveal that by altering sediments cycle and transport, check dams influence soil's main physico-chemical and biochemical characteristics. Significant differences were found between check dam-affected zones and the control ones for many indicators such as organic matter content, electrical conductivity or enzymatic activity. According to the ANOVA results, interaction between check dams influence and time after fire, was a crucial factor. PCA results clearly showed check-dams influence on soil functionality. Copyright © 2018. Published by Elsevier B.V.

Fire Frequency and Vegetation Composition Influence Soil Nitrogen Cycling and Base Cations in an Oak Savanna Ecosystem

NASA Astrophysics Data System (ADS)

McLauchlan, K. K.; Nelson, D. M.; Perakis, S.; Marcotte, A. L.

2017-12-01

Fire frequency is crucial for maintaining savannas in the transition between forests and grasslands. In general, increasing fire frequency has two effects: it increases herbaceous plant cover more than woody plant cover, and it lowers soil organic matter stocks. These effects have been demonstrated at a long-term prescribed fire experiment in an oak savanna ecosystem at Cedar Creek Ecosystem Science Reserve, Minnesota, U.S.A. The fire experiment began in 1964 and oak savannas are burned at various frequencies ranging from every year to not at all. This has led to changes in vegetation ranging from almost 100% grassland to 100% oak forest. Additionally, nitrogen stocks almost doubled in the sites that were not burned, as it accumulated in the trees, leaf litter, and soil. We addressed additional soil changes taking place at this experiment by asking the question: How have fire and oak-grass balance affected soil nutrients, specifically nitrogen and base cations? Surface soils were collected from 12 plots on the oak savanna burn experiment. Soils were collected in increments to 100 cm depth, from under grass-dominated vegetation and from under tree-dominated vegetation. We non-destructively estimated soil base cations by measuring elemental concentrations of dried soil subsamples with a handheld x-ray fluorescence analyzer. We also measured carbon and nitrogen concentrations and isotopic composition of the soil samples. Soils in plots with high fire frequency had higher concentrations of calcium than soils in unburned plots (low fire frequency). Similar trends were seen for soil potassium, magnesium, and phosphorus concentrations. In contrast, soils in plots with high fire frequency had dramatically lowered nitrogen cycling rates and stocks across the oak savanna. The contrast between the responses of different nutrients to changing fire frequency has important implications for the consequences of fire and tree-grass composition on nutrient cycling dynamics.

Soil geochemistry controls fire severity: A soil approach to improved understanding of forest fire consequences in southwest Montana.

NASA Astrophysics Data System (ADS)

Callahan, R.; Hartshorn, T.

2014-12-01

Fire severity can be defined using satellite imagery to ratio mid (~2.2 um) to near (~0.8 um) infrared reflectance values. We examined how lithology and topography affected burn severity, and how post-fire soils data could be used to ground-truth burn severity at two sites in southwestern Montana. A burned area reflectance classification (BARC), lithology, and terrain attributes were used to predict burn severity for the Millie Fire, which was triggered two years ago by lightning and burned ~4,000 ha. Burn severity showed a strong dependence on lithology: the ratio of areas with high burn severity vs. low or moderate burn severities was 2.9 for gneiss (vs. 0.3 for volcanics). The high-severity burn area for the gneiss was larger than the volcanics, despite the latter lithology covering ~270% greater area (~2,600 ha). Aspect and elevation also influenced burn severity with lower severity at higher elevations (2,600-3,000 m) and higher severity at lower elevations (1,800-2,400 m). Southern and western aspects burned more severely than northern and eastern aspects. To clarify whether post-fire soil geochemical changes might predict ground-based estimates of fire severity, a lab experiment was carried out . We expected residual enrichment of trace metal concentrations, as soil organic matter (SOM) was combusted, which we quantified as loss on ignition (LOI). To test this approach, burned and unburned soils were sampled from the ~6000 ha Beartrap 2 fire, which also burned two years. We simulated differing fire severities on unburned soil using a muffle furnace factorially (duration [5, 15, 30, 45, or 60 minutes] x temperature [50, 100, 200, 300, 400, or 500ºC]). Consistent with expectations, unburned samples had a lower mean (±1SD) concentrations for 23 of 30 elements than field-burned samples. For example, barium concentrations ([Ba]) in unburned samples were (708±37μg/g), 16% lower than field-burned [Ba] (841±7 μg/g). Simulated burning yielded smaller [Ba] (732±9 μg/g). Of the 30 trace metals examined, barium explained the greatest fraction of variance in post-burn LOI (R2 =0.79); gallium explained slightly less variance (R2=0.67). Our results document the promise of post-burn soil geochemistry to indicate soil burn severity, which could complement vegetation-based and remotely sensed indices.

Post-fire soil nutrient redistribution in northern Chihuahuan Desert

NASA Astrophysics Data System (ADS)

Wang, G.; Li, J. J.; Ravi, S.; Sankey, J. B.; Duke, D.; Gonzales, H. B.; Van Pelt, S.

2016-12-01

The desert grassland in the southwestern US has undergone dramatic land degradation with woody shrub encroachment over the last 150 years. Wind erosion and periodic fires are major drivers of vegetation dynamics in these ecosystems. Due to climate change and anthropogenic disturbances, many drylands are undergoing changes in fire regimes, which can largely alter the nutrient loss rate as well as the soil resource heterogeneity. In this study, we used manipulative field experiments, laboratory and geostatistical analyses to investigate the distribution of fertile islands, nutrient loss rate and spatial variation. Replicated burned and control experimental plots were set up in a desert grassland in northern Chihuahuan Desert in March 2016. Windblown sediments were monitored by multiple MWAC sediment collectors on each plot. Surface soil samples, with their locations accurately recorded (i.e., under shrub, under grass, and bare interspace) were collected twice per year in spring and again in summer after the experimental setup. Our preliminary results show that the spatial heterogeneity of soil C and N in the burned plots has changed notably compared to the control plots. Our results further demonstrated that areas with burned shrubs is most vulnerable to wind erosion, therefore the soil nutrient loss is most significant, almost five times of the nutrient loss rate of bare areas. Interspace bare areas is in the lowest micro-land and some of the surface has caliche, which makes the surface resistant to wind erosion. And areas with burned grass receive the lightest wind erosion and nutrient loss, around one third of the erosion on bare areas, because burned grasses still cover the surface and the dead bodies can eliminate wind erosion to a large extent. Hence, periodic fire in desert grassland favors the evenness distribution of soil nutrients and can retard the shrub encroachment process.

Post-fire redistribution of soil carbon and nitrogen at a grassland-shrubland ecotone

USGS Publications Warehouse

Wang, Guan; Li, Junran; Ravi, Sujith; Dukes, David; Gonzales, Howell B.; Sankey, Joel B.

2018-01-01

The rapid conversion of grasslands into shrublands has been observed in many arid and semiarid regions worldwide. Studies have shown that fire can provide certain forms of reversibility for shrub-grass transition due to resource homogenization and shrub mortality, especially in the early stages of shrub encroachment. Field-level post-fire soil resource redistribution has rarely been tested. Here we used prescribed fire in a shrubland-grassland transition zone in the northern Chihuahuan Desert to test the hypothesis that fire facilitates the remobilization of nutrient-enriched soil from shrub microsites to grass and bare microsites and thereby reduces the spatial heterogeneity of soil resources. Results show that the shrub microsites had the lowest water content compared to grass and bare microsites after fire, even when rain events occurred. Significant differences of total soil carbon (TC) and total soil nitrogen (TN) among the three microsites disappeared one year after the fire. The spatial autocorrelation distance increased from 1~2 m, approximately the mean size of an individual shrub canopy, to over 5 m one year after the fire for TC and TN. Patches of high soil C and N decomposed one year after the prescribed fire. Overall, fire stimulates the transfer of soil C and N from shrub microsites to nutrient-depleted grass and bare microsites. Such a redistribution of soil C and N, coupled with the reduced soil water content under the shrub canopies, suggests that fire might influence the competition between shrubs and grasses, leading to a higher grass, compared to shrub, coverage in this ecotone.

Forest wildfire increases soil microbial biomass C:N:P stoichiometry in long-term effects

NASA Astrophysics Data System (ADS)

Zhou, Xuan

2017-04-01

Boreal forest fire strongly influences carbon (C) stock in permafrost soil by thawing permafrost table which accelerated microbe decomposition process. We studied soil microbial biomass stoichiometry in a gradient of four (3 yr, 25 yr, 46 yr and more than 100 yr) ages since fire in Canada boreal forest. Soil microbial biomass (MB) in long-term after fire is significantly higher than in short-term. MB C and nitrogen (N) were mainly dominated by corresponding soil element concentration and inorganic P, while MB phosphorus (P) changes were fully explained by soil N. Fire ages and soil temperature positively increased MB N and P, indicating the negative impact by fire. Microbial C:N:P gradually increased with fire ages from 15:2:1 to 76:6:1 and then drop down to 17:2:1 in the oldest fire ages. The degree of homeostasis of microbial C, N and P are close to 1 indicates non-homoeostasis within microbial elements, while it of C:N:P is close to 8 shows a strong homeostasis within element ratios and proved microbial stoichiometric ratio is not driven by soil element ratios. In conclusion, i) microbial biomass elements highly depends on soil nutrient supply rather than fire ages; ii) wildfire decreased microbial stoichiometry immediate after fire but increased with years after fire (YF) which at least 3 times higher than > 100 fire ages; iii) microbial biomass C, N and P deviated from strict homeostasis but C:N:P ratio reflects stronger homeostasis.

Effects of prescribed fires on soil properties: A review.

PubMed

Alcañiz, M; Outeiro, L; Francos, M; Úbeda, X

2018-02-01

Soils constitute one of the most valuable resources on earth, especially because soil is renewable on human time scales. During the 20th century, a period marked by a widespread rural exodus and land abandonment, fire suppression policies were adopted facilitating the accumulation of fuel in forested areas, exacerbating the effects of wildfires, leading to severe degradation of soils. Prescribed fires emerged as an option for protecting forests and their soils from wildfires through the reduction of fuels levels. However such fires can serve other objectives, including stimulating the regeneration of a particular plant species, maintaining biological diversity or as a tool for recovering grasslands in encroached lands. This paper reviews studies examining the short- and long- term impacts of prescribed fires on the physical, chemical and biological soil properties; in so doing, it provides a summary of the benefits and drawbacks of this technique, to help determine if prescribed fires can be useful for managing the landscape. From the study conducted, we can affirm that prescribed fires affects soil properties but differ greatly depending on soil initial characteristics, vegetation or type of fire. Also, it is possible to see that soil's physical and biological properties are more strongly affected by prescribed fires than are its chemical properties. Finally, we conclude that prescribed fires clearly constitute a disturbance on the environment (positive, neutral or negative depending on the soil property studied), but most of the studies reviewed report a good recovery and their effects could be less pronounced than those of wildfires because of the limited soil heating and lower fire intensity and severity. Copyright © 2017. Published by Elsevier B.V.

Using Remotely Sensed Soil Moisture to Estimate Fire Risk in Tropical Peatlands

NASA Astrophysics Data System (ADS)

Dadap, N.; Cobb, A.; Hoyt, A.; Harvey, C. F.; Konings, A. G.

2017-12-01

Tropical peatlands in Equatorial Asia have become more vulnerable to fire due to deforestation and peatland drainage over the last 30 years. In these regions, water table depth has been shown to play an important role in mediating fire risk as it serves as a proxy for peat moisture content. However, water table depth observations are sparse and expensive. Soil moisture could provide a more direct indicator of fire risk than water table depth. In this study, we use new soil moisture retrievals from the Soil Moisture Active Passive (SMAP) satellite to demonstrate that - contrary to popular wisdom - remotely sensed soil moisture observations are possible over most Southeast Asian peatlands. Soil moisture estimation in this region was previously thought to be impossible over tropical peatlands because of dense vegetation cover. We show that vegetation density is sufficiently low across most Equatorial Asian peatlands to allow soil moisture estimation, and hypothesize that deforestation and other anthropogenic changes in land cover have combined to reduce overall vegetation density sufficient to allow soil moisture estimation. We further combine burned area estimates from the Global Fire Emissions Database and SMAP soil moisture retrievals to show that soil moisture provides a strong signal for fire risk in peatlands, with fires occurring at a much greater rate over drier soils. We will also develop an explicit fire risk model incorporating soil moisture with additional climatic, land cover, and anthropogenic predictor variables.

Long term effects of fire on the carbon balance in boreal forests

NASA Astrophysics Data System (ADS)

Berninger, Frank; Köster, Kaja; Pumpanen, Jukka

2013-04-01

Fire is the primary process which organizes the physical and biological attributes of the boreal biome and influences energy flows and biogeochemical cycles, particularly the carbon and nitrogen cycle. We established a forest fire chronosequence in the northern boreal forest in Lapland (Värriö Strict Nature Reserve), Finland (67°46' N, 29°35' E) that spans 160 years. Soil organic matter and its turnover were measured in and ex situ, as well as biomass of trees. The fungal biomass was assessed using soil ergosterol contents. The results indicate that fires slow down the turnover of soil organic matter for a period of at least 50 years. The turnover rate in recently burnt sites was only half of the turnover of the old forest site. Decreases in the turnover where still substantial 50 years after fire. The slow recovery of fungal biomass after fires seems to be the cause of the decrease since sites with a higher concentration of fungal biomass in the soils had shorter soil organic matter turnover rates. Increases in stand foliar biomass were less important for the turnover of soil organic matter. We tried to explore the potential importance of our finding using a simple data driven simulation model that estimates soil carbon dynamic from litter input and the measured soil carbon turnover times. The results indicate the initial post-fire slowdown of soil carbon turnover is an important component of the boreal carbon cycle. Using our fire intervals the simulated soil carbon stocks with a lower post-fire soil organic matter turnover were up to 15 % larger than simulations assuming a constant carbon turnover rate. Our sensitivity analysis indicates that the effects will be larger in areas with frequent fires. We do not know which environmental factors cause the delay in the turnover time and the effects of fires on post fire soil organic matter turnover could be considerably smaller or larger. Altogether our results fit well to published results from laboratory studies and show that post-fire depression of microbial activities are important on the ecosystem and landscape level. Since fire frequencies in boreal forests will increase in many areas as the result of climate change, it will be important to better understand the effects of fire on the soil carbon turnover and to incorporate it into carbon cycle models.

Alteration of soil hydraulic properties and soil water repellency by fire and vegetation succession in a sagebrush steppe ecosystem

NASA Astrophysics Data System (ADS)

Chandler, D. G.; Seyfried, M. S.

2016-12-01

This study explores the impacts of fire and plant community succession on soil water repellency (SWR) and infiltration properties to improve understanding the long term impacts of prescribed fire on SWR and infiltration properties in sagebrush-steppe ecosystem. The objectives of this study were: 1) To explore the temporal effects of prescribed burning in sagebrush dominated landscape; 2) To investigate spatial variability of soil hydrologic properties; 3) To determine the relationship among soil organic fraction, soil hydrophobicity and infiltration properties. Fieldwork was conducted in paired catchments with three dominant vegetation cover communities: Low sage, big mountain sage and aspen. Detailed, heavily replicated analyses were conducted for unsaturated hydraulic conductivity, sorptivity water drop penetration time and static soil-water-air contact angle. The results show that the severity and presence of surface soil water repellency were considerably reduced six years after fire and that hydraulic conductivity increased significantly in each vegetation cover compared to pre-burn condition. Comparisons among soil hydrological properties shows that hydraulic conductivity is not strongly related to SWR, and that sorptivity is negatively correlated with SWR. The spatial variance of hydraulic properties within the burned high sage and low sage, in particularly, spatial variability of hydraulic conductivity is basically controlled by soil texture and sorptivity is affected by soil wettability. The average water repellency in Low Sage area was significantly different with Big Sage and Aspen as the gap of organic content between Low Sage and other vegetation area. The result of contact angle measurement and organic content analysis shows a strong positive correlation between SWR and organic matter.

Postfire soil erosion processes are conditioned by aridity

NASA Astrophysics Data System (ADS)

Jordán, Antonio; Zavala, Lorena M.; Gordillo-Rivero, Ángel J.; Muñoz-Rojas, Miriam; Keesstra, Saskia; Cerdà, Artemi

2017-04-01

In this work we have studied the runoff and rate of erosion in severely burnt Mediterranean shrublands of southern Spain by simulating high intensity rainfall over a period of 5 years. We have also observed temporal changes in soil surface properties (0-10 mm) of two scrub areas in different years. In both cases, surface runoff increased appreciably during the first year after the fire, compared to burning bushes in more rainy areas. Although differences in the rate of infiltration (determined by a mini-disk infiltrometer with ethanol, to avoid the effect of hydrophobicity) were observed, the increase in the rate of runoff was related to the increase of water repellency in the first millimeters of the soil surface, regardless of other physical properties (texture or percentage of rock fragments), chemical (acidity, organic matter content) or fire severity. Sediment loss was also exceptionally high during the first year. Then, runoff and soil loss rates were progressively approaching the values observed in the control zones. However, most of the physical and chemical properties of the soil after the fire did not change during the post-fire period, suggesting erosion of sediment depletion. No large differences were observed between the study points along the precipitation gradient, suggesting that, independently of this and other factors, the impact of high severity fires can be long over time. Although other authors have shown that relatively small changes in aridity have great impacts on erosion processes, this does not seem to be valid in the case of high severity fires in Mediterranean areas.

A soil burn severity index for understanding soil-fire relations in tropical forests

Treesearch

Theresa B. Jain; William A. Gould; Russell T. Graham; David S. Pilliod; Leigh B. Lentile; Grizelle Gonzalez

2008-01-01

Methods for evaluating the impact of fires within tropical forests are needed as fires become more frequent and human populations and demands on forests increase. Short- and long-term fire effects on soils are determined by the prefire, fire, and postfire environments. We placed these components within a fire-disturbance continuum to guide our literature synthesis and...

Is the current increase in fire recurrence causing a shift in the soil fertility of Iberian ecosystems?

NASA Astrophysics Data System (ADS)

Mayor, Ángeles G.; Keizer, Jan Jacob; González-Pelayo, Óscar; Valdecantos, Alejandro; Vallejo, Ramón; de Ruiter, Peter

2015-04-01

Since the mid of the last century fire recurrence has increased in the Iberian peninsula and the overall Mediterranean basin due to changes in land use and climate. The warmer and drier climate projected for this region will further increase the risk of wildfire occurrence and of increasing fire recurrence. Although the impact of wildfires on soil nutrient content in this region has been extensively studied, still few works have assessed this impact on the basis of fire recurrence. This study assesses the changes in soil nutrient status of two Iberian ecosystems, Várzea (N Portugal) and Valencia (E Spain), affected by different levels of fire recurrence and where short inter-fire periods have promoted a transition from pine woodlands to shrublands. Trends towards soil fertility loss with increasing fire recurrence (one, two, three or four fires in 37 years) were observed in the two study sites. The sites differed when soil fertility of areas burned several times were compared with long unburned references. In Valencia, overall soil fertility of the surface mineral soil was lower in areas burned two or three times than in long unburned areas, twenty and eight years after the last fire, respectively. On the contrary, total organic matter in Várzea was higher in burned than in unburned soils one year after the occurrence of one or four fires. However, a negative impact of fire was observed for integrated indicators of soil quality, such as hot-water carbon and potentially mineralizable nitrogen, suggesting that fire also had an adverse effect on substrate quality in Várzea. Our results suggest that the current trend of increasing fire recurrence in Southern Europe may result in losses or alterations of soil organic matter, particularly when fire promotes a transition from pine woodland to shrubland.

Extensive Burn Scars in Russia's Amur Region

NASA Technical Reports Server (NTRS)

2002-01-01

Vast areas of southeastern Russia have been scorched by fires over the last few weeks. All across Siberia fires have been raging, and this Moderate Resolution Imaging Spectroradiometer (MODIS) image from May 15, 2002, shows extensive, dark burn scars along with actively burning fires (red dots) on the north side of the Amur River, which separates Russia (north) and China (south). The southern Amur region is largely devoted to farming and other agriculture, and these fires may have been set intentionally to prepare the land for the growing season. Fire is often used to clear land of unwanted vegetation, and to return the nutrients stored in vegetation back to the soil. However, fires that are too frequent or severe can devastate the soil, eventually making it unsuitable for farming or grazing. Fires can also escape control and spread into protected areas. In this image, fires are mostly concentrated in a lowland area within the drainage basin of the Zeya River, which drains from the frozen lake at the top of the image. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

Fire severity is more sensitive to low fuel moisture content on Calluna heathlands than on peat bogs.

PubMed

Grau-Andrés, Roger; Davies, G Matt; Gray, Alan; Scott, E Marian; Waldron, Susan

2018-03-01

Moorland habitats dominated by the dwarf shrub Calluna vulgaris provide important ecosystem services. Drought is projected to intensify throughout their range, potentially leading to increased fire severity as moisture is a key control on severity. We studied the effect of low fuel moisture content (FMC) on fire severity by using 2×2m rain-out shelters prior to completing 19 experimental fires in two sites in Scotland (UK): a dry heath with thin organic soils and a raised bog with deep, saturated peat, both dominated by Calluna vulgaris. Reduced FMC of the moss and litter (M/L) layer at both sites, and the soil moisture of the dry heath, increased fire-induced consumption of the M/L layer and soil heating at both sites. Increase in fire severity was greater at the dry heath than at the raised bog, e.g. average maximum temperatures at the soil surface increased from 31°C to 189°C at the dry heath, but only from 10°C to 15°C at the raised bog. Substantial M/L layer consumption was observed when its FMC was below 150%. This led to larger seasonal and daily soil temperature fluctuation, particularly at the dry heath during warm months. The results suggest that low FMC following predicted changes in climate are likely to increase wildfire severity and that the impact on vegetation composition and carbon stores may be greater at heathlands than at peatlands. Managed burning aiming to minimise fire severity (e.g. ignition of the M/L layer and exposure to lethal temperatures of ericoid seeds) should be carried out when the FMC of the M/L layer is above 150% and the FMC of the soil is above 200-300%. Copyright © 2017 Elsevier B.V. All rights reserved.

The influence of wildfire severity on soil char composition and nitrogen dynamics

NASA Astrophysics Data System (ADS)

Rhoades, Charles; Fegel, Timothy; Chow, Alex; Tsai, Kuo-Pei; Norman, John, III; Kelly, Eugene

2017-04-01

Forest fires cause lasting ecological changes and alter the biogeochemical processes that control stream water quality. Decreased plant nutrient uptake is the mechanism often held responsible for lasting post-fire shifts in nutrient supply and demand, though other upland and in-stream factors also likely contribute to elevated stream nutrient losses. Soil heating, for example, creates pyrogenic carbon (C) and char layers that influence C and nitrogen (N) cycling. Char layer composition and persistence vary across burned landscapes and are influenced first by fire behavior through the temperature and duration of combustion and then by post-fire erosion. To evaluate the link between soil char and stream C and N export we studied areas burned by the 2002 Hayman Fire, the largest wildfire in Colorado, USA history. We compared soil C and N pools and processes across ecotones that included 1) unburned forests, 2) areas with moderate and 3) high wildfire severity. We analyzed 1-2 cm thick charred organic layers that remain visible 15 years after the fire, underlying mineral soils, and soluble leachate from both layers. Unburned soils released more dissolved organic C and N (DOC and DON) from organic and mineral soil layers than burned soils. The composition of DOC leachate characterized by UV-fluorescence, emission-excitation matrices (EEMs) and Fluorescence Regional Integration (FRI) found similarity between burned and unburned soils, underscoring a common organic matter source. Humic and fulvic acid-like fractions, contained in regions V and III of the FRI model, comprised the majority of the fluorescing DOM in both unburned and char layers. Similarity between two EEMs indices (Fluorescence and Freshness), further denote that unburned soils and char layers originate from the same source and are consistent with visual evidence char layers contain significant amounts of unaltered OM. However, the EEMs humification index (HIX) and compositional analysis with pyrolysis GCMS both indicate that C contained or leached from severely-burned char layers has higher aromaticity and thus chemical stability compared to C in unburned soils. Mineral soil (0-5 cm depth) beneath char layers in high severity portions of the Hayman Fire had significantly more soil N and C and lower pH. Potential net mineralization - an index of the supply of plant-available nitrogen - differed between the severely-burned areas and both unburned and moderately-burn areas. Negative net mineralization in unburned and moderately burned soils indicates immobilization or retention of inorganic N by soil microbes. In contrast, soils burned at high severity produced inorganic N sources available to plants, leaching and gas losses. Water soluble nitrate comprised a larger proportion of inorganic N leached from the char layer of high severity burns. Mineral soil in those areas had both higher water soluble nitrate and total inorganic N in leachate. Char layers that have persisted for fifteen years influence soil N turnover within the Hayman Fire affected area and may contribute to elevated N losses in streams burned at high severity. The chemical stability of soil char layers perpetuates their importance for C sequestration and N dynamics in burned landscapes.

Record of Decision for the First Air National Guard F-35A Operational Base

DTIC Science & Technology

2013-12-02

Air Quality • Employ fugitive dust control and soil retention practices including: - Water trucks or sprinkler systems to keep all areas of vehicle...with local fire departments on F-35A crash response procedures. Soils and Water • Sequence construction activities to limit the soil exposure for

Effect of a long-term fire retardant (Fire Trol 934) on the germination of nine Mediterranean-type shrub species.

PubMed

Cruz, Alberto; Serrano, Marián; Navarro, Esther; Luna, Belén; Moreno, José M

2005-12-01

Fire Trol 934 is a long-term fire retardant commonly used in fire prevention and extinction. Our objective was to determine the effect of this chemical on seed germination of nine plant species from Mediterranean-type shrublands, where these chemicals are potentially used. Seeds were exposed to five different Fire Trol concentrations, (0 (control) to 10%, on a log scale) and monitored in a germination chamber for nine weeks. Seeds from four Cistus species were subjected to an additional heat treatment that simulated thermal scarification caused by fire. Retardant exposure caused a significant decrease in total germination in all species, and exposure to the highest Fire Trol concentration (10%) resulted in complete inhibition of germination. However, the sensitivity to Fire Trol varied across species and this differential species sensitivity may potentially lead to different impacts in the soil seed banks depending on whether sites are burned or unburned. Exposure to Fire Trol 934 may affect recruitment of shrubland species particularly during dry autumns, due to limited leaching of these chemicals from the soil surface. Consequently, its use should be avoided in sites where particularly sensitive plant species are present. Copyright (c) 2005 Wiley Periodicals, Inc.

Hydraulic redistribution affects modeled carbon cycling via soil microbial activity and suppressed fire.

PubMed

Fu, Congsheng; Wang, Guiling; Bible, Kenneth; Goulden, Michael L; Saleska, Scott R; Scott, Russell L; Cardon, Zoe G

2018-04-13

Hydraulic redistribution (HR) of water from moist to drier soils, through plant roots, occurs world-wide in seasonally dry ecosystems. Although the influence of HR on landscape hydrology and plant water use has been amply demonstrated, HR's effects on microbe-controlled processes sensitive to soil moisture, including carbon and nutrient cycling at ecosystem scales, remain difficult to observe in the field and have not been integrated into a predictive framework. We incorporated a representation of HR into the Community Land Model (CLM4.5) and found the new model improved predictions of water, energy, and system-scale carbon fluxes observed by eddy covariance at four seasonally dry yet ecologically diverse temperate and tropical AmeriFlux sites. Modeled plant productivity and microbial activities were differentially stimulated by upward HR, resulting at times in increased plant demand outstripping increased nutrient supply. Modeled plant productivity and microbial activities were diminished by downward HR. Overall, inclusion of HR tended to increase modeled annual ecosystem uptake of CO 2 (or reduce annual CO 2 release to the atmosphere). Moreover, engagement of CLM4.5's ground-truthed fire module indicated that though HR increased modeled fuel load at all four sites, upward HR also moistened surface soil and hydrated vegetation sufficiently to limit the modeled spread of dry season fire and concomitant very large CO 2 emissions to the atmosphere. Historically, fire has been a dominant ecological force in many seasonally dry ecosystems, and intensification of soil drought and altered precipitation regimes are expected for seasonally dry ecosystems in the future. HR may play an increasingly important role mitigating development of extreme soil water potential gradients and associated limitations on plant and soil microbial activities, and may inhibit the spread of fire in seasonally dry ecosystems. © 2018 John Wiley & Sons Ltd.

A soil burn severity index for understanding soil-fire relations in tropical forests [Chinese version

Treesearch

Theresa B. Jain; William A. Gould; Russell T. Graham; David S. Pilliod; Leigh B. Lentile; Grizelle Gonzalez

2008-01-01

Methods for evaluating the impact of fires within tropical forests are needed as fires become more frequent and human populations and demands on forests increase. Short- and long-term fire effects on soils are determined by the prefire, fire, and postfire environments. We placed these components within a fire-disturbance continuum to guide our literature synthesis and...

Biological soil crust response to late season prescribed fire in a Great Basin juniper woodland

Treesearch

Steven D. Warren; Larry L. St.Clair; Jeffrey R. Johansen; Paul Kugrens; L. Scott Baggett; Benjamin J. Bird

2015-01-01

Expansion of juniper on U.S. rangelands is a significant environmental concern. Prescribed fire is often recommended to control juniper. To that end, a prescribed burn was conducted in a Great Basin juniper woodland. Conditions were suboptimal; fire did not encroach into mid- or late-seral stages and was patchy in the early-seral stage. This study evaluated the effects...

Soil carbon in Australian fire-prone forests determined by climate more than fire regimes.

PubMed

Sawyer, Robert; Bradstock, Ross; Bedward, Michael; Morrison, R John

2018-10-15

Knowledge of global C cycle implications from changes to fire regime and climate are of growing importance. Studies on the role of the fire regime in combination with climate change on soil C pools are lacking. We used Bayesian modelling to estimate the soil % total C (% C Tot ) and % recalcitrant pyrogenic C (% RPC) from field samples collected using a stratified sampling approach. These observations were derived from the following scenarios: 1. Three fire frequencies across three distinctive climate regions in a homogeneous dry sclerophyll forest in south-eastern Australia over four decades. 2. The effects of different fire intensity combinations from successive wildfires. We found climate had a stronger effect than fire frequency on the size of the estimated mineral soil C pool. The largest soil C pool was estimated to occur under a wet and cold (WC) climate, via presumed effects of high precipitation, an adequate growing season temperature (i.e. resulting in relatively high NPP) and winter conditions sufficiently cold to retard seasonal soil respiration rates. The smallest soil C pool was estimated in forests with lower precipitation but warmer mean annual temperature (MAT). The lower precipitation and higher temperature was likely to have retarded NPP and litter decomposition rates but may have had little effect on relative soil respiration. Small effects associated with fire frequency were found, but both their magnitude and direction were climate dependent. There was an increase in soil C associated with a low intensity fire being followed by a high intensity fire. For both fire frequency and intensity the response of % RPC mirrored that of % C Tot : i.e. it was effectively a constant across all combinations of climate and fire regimes sampled. Copyright © 2018. Published by Elsevier B.V.

Micromorphological characteristics of sandy forest soils recently impacted by wildfires in Russia

NASA Astrophysics Data System (ADS)

Maksimova, Ekaterina; Abakumov, Evgeny

2017-04-01

Two fire-affected soils were studied using micromorphological methods. The objective of the paper is to assess and compare fire effects on the micropedological organisation of soils in a forest-steppe zone of central Russia (Volga Basin, Togliatti city). Samples were collected in the green zone of Togliatti city. The results showed that both soils were rich in quartz and feldspar. Mica was highly present in soils affected by surface fires, while calcium carbonates were identified in the soils affected by crown fires. The type of plasma is humus-clay, but the soil assemblage is plasma-silt with a prevalence of silt. Angular and subangular grains are the most dominant soil particulates. No evidence of intensive weathering was detected. There was a decrease in the porosity of soils affected by fires as a consequence of soil pores filled with ash and charcoal.

Nitrogen mineralization in aspen/conifer soils after a natural fire

Treesearch

Michael C. Amacher; Dale L. Bartos; Tracy Christopherson; Amber D. Johnson; Debra E. Kutterer

2001-01-01

We measured the effects of the 1996 Pole Creek fire, Fishlake National Forest, Utah, on available soil N and net N mineralization for three summers after the fire using an ion exchange membrane (IEM) soil core incubation method. Fire in mixed aspen/conifer increased the amount of available NH4, and a subsequent net increase in soil nitrification was observed. Release...

Wildfire in the Critical Zone: Pyro-Geomorphic Feedbacks in Upland Forests

NASA Astrophysics Data System (ADS)

Sheridan, G. J.; Inbar, A.; Metzen, D.; Van der Sant, R.; Lane, P. N. J.; Nyman, P.

2017-12-01

Wildfire often triggers a dramatic geomorphic response, with erosion rates several orders of magnitude greater than background rates. The fact that wildfire is linked to increased soil erosion is well established, but could it also work the other way around? Is it possible that, over time, soil erosion could lead to an increase in wildfire? The proposed mechanism for this is a potential positive feedback between post-fire soil erosion, soil depth, and forest flammability. More fire-related erosion may, over time, lead to less soil water holding capacity, more open vegetation with drier fuels, more fire, and in turn more fire related erosion. These pyro-geomorphic feedbacks may help explain the co-evolved soil-vegetation-fire systems that are observed in the landscape. More broadly, the concept of "wildfire in the critical zone", with a greater emphasis on the interactions between fire, vegetation, hydrology, and geomorphology, may help us understand and predict the trajectory of change as the vegetation-soil-fire system responds and adjusts to the new climate forcing. This presentation will combine an extensive soil, vegetation, and post fire erosion experimental dataset, with conceptual and numerical modelling, to evaluate the significance of the potential pyro-geomorphic feedbacks described above.

Peat fires as source of polycyclic aromatic hydrocarbons in soils

NASA Astrophysics Data System (ADS)

Tsibart, Anna

2013-04-01

Polycyclic aromatic hydrocarbons (PAHs) arrive from pyrogenic sources including volcanism and the combustion of oil products and plant materials. The production of PAHs during the combustion of plant materials was considered in a number of publications, but their results were mainly obtained in laboratory experiments. Insufficient data are available on the hightemperature production of PAHs in environmental objects. For example, natural fires are frequently related to the PAH sources in landscapes, but very little factual data are available on this topic. On Polistovskii reserve (Russia, Pskov region) the soil series were separated depending on the damage to the plants; these series included soils of plots subjected to fires of different intensities, as well as soils of the background plots. The series of organic and organomineral soils significantly differed in their PAH distributions. In this series, the concentration of PAHs in the upper horizons of the peat soils little varied or slightly decreased, but their accumulation occurred at a depth of 5-10 or 10-20 cm in the soils after the fires. For example, in the series of high moor soils, the content of PAHs in the upper horizons remained almost constant; significant differences were observed in the subsurface horizons: from 2 ng/g in the background soil to 70 ng/g after the fire. In the upper horizons of the oligotrophic peat soils under pine forests, the total PAH content also varied only slightly. At the same time, the content of PAHs in the soil series increased from 15 to 90 ng/g with the increasing pyrogenic damage to the plot. No clear trends of the PAH accumulation were recorded in the organomineral soils. The content of PAHs in the soddy-podzolic soil subjected to fire slightly decreased (from 20 to 10 ng/g) compared to the less damaged soil. In peat fires, the access of oxygen to the fire zone is lower than in forest fires. The oxygen deficit acts as a factor of the organic fragments recombination and PAH production; therefore, larger amounts of PAHs are formed in peat fires. In addition, the peat fires occur directly in the soil layer; therefore, larger amounts of the resulting polyarenes remain in the soils of the fire sites. PAHs also can be formed at the heating of organic matter on the areas adjacent to the fire sites. After the combustion of peat in fires, phenanthrene, chrysene, benz[a]pyrene, and tetraphene accumulate in soils. This is mainly the group of 4-nuclear compounds with the participation of 3-nuclear phenanthrene and 5-nuclear benz[a]pyrene. The formation of high-molecular weight compounds like benz[a]pyrene and, in some places, benzo[ghi]perylene is possible during smoldering under a low oxygen supply.

Carbon combustion in boreal black spruce and jack pine stands of the Northwest Territories, Canada

NASA Astrophysics Data System (ADS)

Walker, X. J.; Baltzer, J. L.; Cumming, S.; Day, N.; Goetz, S. J.; Johnstone, J. F.; Rogers, B. M.; Turetsky, M. R.; Mack, M. C.

2017-12-01

Increased fire frequency, extent, and severity is expected to strongly impact the structure and function of northern ecosystems. One of the most important functions of the boreal forest is its ability to sequester and store carbon (C). Increases in combustion of vegetation and organic soils, associated with an intensifying fire regime, could shift this biome across a C cycle threshold: from net accumulation of C from the atmosphere over multiple fire cycles, to a net loss, which in turn would cause a positive feedback to climate warming. In order for this shift to occur, fires would have to release old carbon that escaped combustion in one or more previous fires. In this study, we examined boreal black spruce and jack pine forests that burned during the 2014 fire season in the Northwest Territories, Canada. We assessed both aboveground and soil organic layer (SOL) combustion, with the goal of determining how fire weather, site environmental conditions, and pre-fire stand characteristics affect total C emissions. On average 3.35 Kg C /m2 was combusted and almost 90% of this can be attributed to combustion of the SOL. Our results indicate that the greatest carbon combustion occurs at mature black spruce sites in intermediately drained landscape positions and that variables associated with fire weather and date of burn are not important predictors of C combustion. We then used radiocarbon dating of the residual soil organic layer to determine the maximum age of soil C lost. Dates of the residual surface organic layers in a low ( 5 cm) and high ( 17 cm) severity burn were approximately 1995 and 1900, respectively. These preliminary results indicate that our metrics of burn depth are related to age of the soil C lost and suggest that high severity burns can result in combustion of old C. Using these data, we aim to determine if there are ecosystem, landscape, or regional controls that either facilitate or protect old C loss from combustion. Estimating changes in C combustion and C storage is essential for assessing the consequences of an altered fire regime on permafrost dynamics, vegetation regeneration, and the initiation of successional trajectories in boreal ecosystems.

Fire intensity drives post-fire temporal pattern of soil carbon accumulation in Australian fire-prone forests.

PubMed

Sawyer, Robert; Bradstock, Ross; Bedward, Michael; Morrison, R John

2018-01-01

The impact of fire on global C cycles is considerable but complex. Nevertheless, studies on patterns of soil C accumulation following fires of differing intensity over time are lacking. Our study utilised 15 locations last burnt by prescribed fire (inferred low intensity) and 18 locations last burnt by wildfire (inferred high intensity), with time since fire (TSF) up to 43years, in a homogenous forest type in south eastern Australia. Following a stratified approach to mineral soil sampling, the soil % total C (% C Tot ) and % recalcitrant pyrogenic C (% RPC), were estimated. Generalised additive models indicated increases in % C Tot at TSF >30years in sites last burnt by wildfire. Estimates in sites last subjected to prescribed fire however, remained constant across the TSF chronosequence. There was no significant difference in % C Tot between the different fire types for the first 20years after fire. In the first 10years after wildfires, % RPC was elevated, declining to a minimum at ca. TSF 25years. After prescribed fires, % RPC was unaffected by TSF. Differences in response of % C Tot and % RPC to fire type may reflect the strength of stimulation of early successional processes and extent of charring. The divergent response to fire type in % C Tot was apparent at TSF longer than the landscape average fire return interval (i.e., 15 to 20years). Thus, any attempt to increase C sequestration in soils would require long-term exclusion of fire. Conversely, increased fire frequency is likely to have negligible impact on soil C stocks in these forests. Further investigation of the effects of fire frequency, fire intensity combinations and interaction of fire with other disturbances will enhance prediction of the likely impact of imposed or climatically induced changes to fire regimes on soil C. Copyright © 2017 Elsevier B.V. All rights reserved.

Levels and patterns of polycyclic aromatic hydrocarbons (PAHs) in soils after forest fires in South Korea.

PubMed

Kim, Eun Jung; Choi, Sung-Deuk; Chang, Yoon-Seok

2011-11-01

To investigate the influence of biomass burning on the levels of polycyclic aromatic hydrocarbons (PAHs) in soils, temporal trends and profiles of 16 US Environmental Protection Agency priority PAHs were studied in soil and ash samples collected 1, 5, and 9 months after forest fires in South Korea. The levels of PAHs in the burnt soils 1 month after the forest fires (mean, 1,200 ng/g dry weight) were comparable with those of contaminated urban soils. However, 5 and 9 months after the forest fires, these levels decreased considerably to those of general forest soils (206 and 302 ng/g, respectively). The burnt soils and ash were characterized by higher levels of light PAHs with two to four rings, reflecting direct emissions from biomass burning. Five and 9 months after the forest fires, the presence of naphthalene decreased considerably, which indicates that light PAHs were rapidly volatilized or degraded from the burnt soils. The temporal trend and pattern of PAHs clearly suggests that soils in the forest-fire region can be contaminated by PAHs directly emitted from biomass burning. However, the fire-affected soils can return to the pre-fire conditions over time through the washout and wind dissipation of the ash with high content of PAHs as well as vaporization or degradation of light PAHs.

Effects of fire on the thermal stability of permafrost in lowland and upland black spruce forests of interior Alaska in a changing climate

USGS Publications Warehouse

Jafarov, Elchin E.; Romanovsky, Vladimir E.; Genet, Helene; McGuire, Anthony David; Marchenko, Sergey S.

2013-01-01

Fire is an important factor controlling the composition and thickness of the organic layer in the black spruce forest ecosystems of interior Alaska. Fire that burns the organic layer can trigger dramatic changes in the underlying permafrost, leading to accelerated ground thawing within a relatively short time. In this study, we addressed the following questions. (1) Which factors determine post-fire ground temperature dynamics in lowland and upland black spruce forests? (2) What levels of burn severity will cause irreversible permafrost degradation in these ecosystems? We evaluated these questions in a transient modeling–sensitivity analysis framework to assess the sensitivity of permafrost to climate, burn severity, soil organic layer thickness, and soil moisture content in lowland (with thick organic layers, ~80 cm) and upland (with thin organic layers, ~30 cm) black spruce ecosystems. The results indicate that climate warming accompanied by fire disturbance could significantly accelerate permafrost degradation. In upland black spruce forest, permafrost could completely degrade in an 18 m soil column within 120 years of a severe fire in an unchanging climate. In contrast, in a lowland black spruce forest, permafrost is more resilient to disturbance and can persist under a combination of moderate burn severity and climate warming.

Short- term effects of post-fire logging on runoff and soil erosion at two spatial scales

NASA Astrophysics Data System (ADS)

Malvar, Maruxa; Silva, Flavio; Prats, Sergio; Vieira, Diana; Keizer, Jacob

2017-04-01

Logging is the most common management practice after wildfires in forested areas in Portugal. Clearcutting is undertaken to recover burnt timber resources, to control resprouting, notably in the case of eucalypt plantations, and to reduce the risks of possible insect plagues, notably in the case of maritime pine because of the nematode plague. Still, relatively little is known about the combined effect of wildfire and post-fire logging on erosion processes. In the framework of the EU-FP7 project RECARE (www.recare-project.eu), the ESP team of the University of Aveiro set up an experiment to quantify the hydrological and erosion impacts of post-fire logging, at the scale of both 0.25 m2 micro-plots and 16 m2 plots. A eucalypt slope burnt in August 2015 by a moderate intensity fire and logged in September 2015 was selected for this study. The burned trees were harvested with a chainsaw, while the logs were piled with a rubber wheeled forwarder tractor. Following logging, two distinct sub-areas were identified within the logged slope based on soil disturbance: an area where the forwarder wheels had left marked trails ("trail"), and an area where such trails were absent ("control"). Three micro-plots and three plots were installed in the control area, while three micro-plots and six plots were installed in the trail area. Generally, the trail area showed greater soil compaction and larger soil surface roughness than the control area. Between October 2015 and September 2016, mean runoff was 500 mm in the control micro-plots and 50% higher in the trail micro-plots. At the plot scale, however, no differences in runoff generation were observed between the two subareas. Sediment production over the same period, however, was twice as high in the trail area than the control area, at both plot scales. In the control area, mean sediment production was 8 Mg ha-1 yr-1 at the micro-plot scale and 6 Mg ha-1 yr-1at the plot scale; in the trail area, these figures were 21 Mg ha-1 yr-1 and 13 Mg ha-1 yr-1, respectively. Post-fire logging activities and their timing should be evaluated against their potential impacts on runoff and erosion, and should be contemplated for additional erosion mitigation practices.

Monitoring Soil Erosion on a Burned Site in the Mojave-Great Basin Transition Zone: Final Report for the Jacob Fire Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, Julianne; Etyemezian, Vic; Cablk, Mary E.

A historic return interval of 100 years for large fires in the U.S. southwestern deserts is being replaced by one where fires may reoccur as frequently as every 20 to 30 years. The shortened return interval, which translates to an increase in fires, has implications for management of Soil Corrective Action Units (CAUs) and Corrective Action Sites (CASs) for which the Department of Energy, National Nuclear Security Administration Nevada Field Office has responsibility. A series of studies was initiated at uncontaminated analog sites to better understand the possible impacts of erosion and transport by wind and water should contaminated soilmore » sites burn. The first of these studies was undertaken at the Jacob Fire site approximately 12 kilometers (7.5 miles) north of Hiko, Nevada. A lightning-caused fire burned approximately 200 hectares during August 6-8, 2008. The site is representative of a transition between Mojave and Great Basin desert ecoregions on the Nevada National Security Site (NNSS), where the largest number of Soil CAUs/CASs are located. The area that burned at the Jacob Fire site was primarily a Coleogyne ramosissima (blackbrush) and Ephedra nevadensis (Mormon tea) community, also an abundant shrub assemblage in the similar transition zone on the NNSS. This report summarizes three years of measurements after the fire. Seven measurement campaigns at the Jacob Fire site were completed. Measurements were made on burned ridge (upland) and drainage sites, and on burned and unburned sites beneath and between vegetation. A Portable In-Situ Wind Erosion Lab (PI-SWERL) was used to estimate emissions of suspended particles at different wind speeds. Context for these measurements was provided through a meteorological tower that was installed at the Jacob Fire site to obtain local, relevant environmental parameters. Filter samples, collected from the exhaust of the PI-SWERL during measurements, were analyzed for chemical composition. Runoff and water erosion were quantified through a series of rainfall/runoff simulation tests in which controlled amounts of water were delivered to the soil surface in a specified amount of time. Runoff data were collected from understory and interspace soils on burned ridge and drainage areas. Runoff volume and suspended sediment in the runoff were sampled; the particle size distribution of the sediment was determined by laboratory analysis. Several land surface and soil characteristics associated with runoff were integrated by the calculation of site-specific curve numbers. Several vegetation surveys were conducted to assess post-burn recovery. Data from plots in both burned and unburned areas included species identification, counts, and location. Characterization of fire-affected area included measures at both the landscape scale and at specific sites. Although wind erosion measurements indicate that there are seasonal influences on almost all parameters measured, several trends were observed. PI-SWERL measurements indicated the potential for PM10 windblown dust emissions was higher on areas that were burned compared to areas that were not. Among the burned areas, understory soils in drainage areas were the most emissive, and interspace soils along burned ridges were least emissive. By 34 months after the burn (MAB), at the end of the study, emissions from all burned soil sites were virtually indistinguishable from unburned levels. Like the amount of emissions, the chemical signature of the fire (indicated by the EC-Soil ratio) was elevated immediately after the fire and approached pre-burn levels by 24 MAB. Thus, the potential for wind erosion at the Jacob Fire site, as measured by the amount and type of emissions, increased significantly after the fire and returned to unburned levels by 24 MAB. The effect of fire on the potential for water erosion at the Jacob Fire site was more ambiguous. Runoff and sediment from ridge interspace soils and unburned interspace soils were similar throughout the study period. Seldom, if ever, did runoff and sediment occur in burned drainage area soils. For burned soils where runoff occurred at 1 MAB, the sediment size was finer than on unburned sites, but this effect disappeared by 3 MAB. For the three year study under the conditions tested at the Jacob Fire site, the potential for water erosion appeared relatively unaffected by the fire. Vegetation responses were documented for each year following the fire. By the end of the study, there was a substantial difference in plant densities and richness between drainage and ridge sites. Cheatgrass densities were higher in unburned plots, and cheatgrass was also more dominant in the community composition in unburned plots. Cheatgrass had increased in the burned area but so did other native species. Three years after the fire, the burned landscape continued to revegetate but had yet to approximate the condition of an unburned landscape. The results from the vegetation surveys support the wind erosion results, where the primary source of windborne particles originate from the understory, where lower plant diversity and densities were found. The soil appears to be more resilient and have a much shorter recovery time than the vegetation in this particular community.« less

Prescribed burning impact on forest soil properties--a Fuzzy Boolean Nets approach.

PubMed

Castro, Ana C Meira; Paulo Carvalho, Joao; Ribeiro, S

2011-02-01

The Portuguese northern forests are often and severely affected by wildfires during the Summer season. These occurrences significantly affect and negatively impact all ecosystems, namely soil, fauna and flora. In order to reduce the occurrences of natural wildfires, some measures to control the availability of fuel mass are regularly implemented. Those preventive actions concern mainly prescribed burnings and vegetation pruning. This work reports on the impact of a prescribed burning on several forest soil properties, namely pH, soil moisture, organic matter content and iron content, by monitoring the soil self-recovery capabilities during a one year span. The experiments were carried out in soil cover over a natural site of Andaluzitic schist, in Gramelas, Caminha, Portugal, which was kept intact from prescribed burnings during a period of four years. Soil samples were collected from five plots at three different layers (0-3, 3-6 and 6-18) 1 day before prescribed fire and at regular intervals after the prescribed fire. This paper presents an approach where Fuzzy Boolean Nets (FBN) and Fuzzy reasoning are used to extract qualitative knowledge regarding the effect of prescribed fire burning on soil properties. FBN were chosen due to the scarcity on available quantitative data. The results showed that soil properties were affected by prescribed burning practice and were unable to recover their initial values after one year. Copyright © 2010 Elsevier Inc. All rights reserved.

Effects of post-fire soil hydrophobicity on inorganic soil nitrogen and sulfur cycling

USDA-ARS?s Scientific Manuscript database

Fire plays an important role in many native ecosystems, and its suppression has increased woody encroachment across the globe. Restoring native herbaceous communities following fire in encroached systems is often challenging. Post-fire soil hydrophobicity is one factor that may further limit site re...

Temporal characterisation of soil-plant natural recovery related to fire severity in burned Pinus halepensis Mill. forests.

PubMed

Moya, D; González-De Vega, S; García-Orenes, F; Morugán-Coronado, A; Arcenegui, V; Mataix-Solera, J; Lucas-Borja, M E; De Las Heras, J

2018-05-28

Despite Mediterranean ecosystems' high resilience to fire, both climate and land use change, and alterations in fire regimes increase their vulnerability to fire by affecting the long-term natural recovery of ecosystem services. The objective of this work is to study the effects of fire severity on biochemical soil indicators, such as chemical composition or enzymatic activity, related to time after fire and natural vegetation recovery (soil-plant interphase). Soil samples from three wildfires occurring 3, 15 and 21 years ago were taken in the south-eastern Iberian Peninsula (semiarid climate). Sampling included three fire severity levels in naturally regenerated (and changing to shrublands) Pinus halepensis Mill. forests. In the short-term post-fire period, phosphorus concentration, electrical conductivity and urease activity were positively linked to fire severity, and also influenced β-glucosidade activity in a negative relationship. During the 15-21-year post-fire period, the effects related to medium-high fire severity were negligible and soil quality indicators were linked to natural regeneration success. The results showed that most soil properties recovered in the long term after fire (21 years). These outcomes will help managers and stakeholders to implement management tools to stabilise soils and to restore burned ecosystems affected by medium-high fire severity. Such knowledge can be considered in adaptive forest management to reduce the negative effects of wildfires and desertification, and to improve the resilience of vulnerable ecosystems in a global change scenario. Copyright © 2018 Elsevier B.V. All rights reserved.

Spatial distribution of soil moisture and hydrophobicity in the immediate period after a grassland fire in Lithuania

NASA Astrophysics Data System (ADS)

Pereira, P.; Pundyte, N.; Vaitkute, D.; Cepanko, V.; Pranskevicius, M.; Ubeda, X.; Mataix-Solera, J.; Cerda, A.

2012-04-01

Fire can affect significantly soil moisture (SM) and water repellency (WR) in the immediate period after the fire due the effect of the temperatures into soil profile and ash. This impact can be very heterogeneous, even in small distances, due to different conditions of combustion (e.g. fuel and soil moisture, fuel amount and type, distribution and connection, and geomorphological variables as aspect and slope) that influences fire temperature and severity. The aim of this work it is study the spatial distribution of SM and WR in a small plot (400 m2 with a sampling distance of 5 m) immediately after the a low severity grassland fire.. This was made in a burned but also in a control (unburned) plot as reference to can compare. In each plot we analyzed a total of 25 samples. SM was measured gravimetrically and WR with the water drop penetration time test (WDPT). Several interpolation methods were tested in order to identify the best predictor of SM and WR, as the Inverse Distance to a Weight (IDW) (with the power of 1,2,3,4 and 5), Local Polynomial with the first and second polynomial order, Polynomial Regression (PR), Radial Basis Functions (RBF) as Multilog (MTG), Natural Cubic Spline (NCS), Multiquadratic (MTQ), Inverse Multiquadratic (IMTQ) and Thin Plate Spline (TPS) and Ordinary Kriging. Interpolation accuracy was observed with the cross-validation method that is achieved by taking each observation in turn out of the sample and estimating from the remaining ones. The errors produced in each interpolation allowed us to calculate the Root Mean Square Error (RMSE). The best method is the one that showed the lower RMSE. The results showed that on average the SM in the control plot was 13.59 % (±2.83) and WR 2.9 (±1.3) seconds (s). The majority of the soils (88%) were hydrophilic (WDPT <5s). SM in the control plot showed a weak negative relationship with WR (r=-0.33, p<0.10). The coefficient of variation (CV%) of SM was 20.77% and SW of 44.62%. In the burned plot, SM was 14.17% (±2.83) and WR of 151 (±99) seconds (s). All the samples analysed were considered hydrophobic (WDPT >5s). We did not identify significant relationships among the variables (r=0.06, p>0.05) and the CV% was higher in WR (65.85%) than SM (19.96%). Overall we identified no significant changes in SM between plots, which means that fire did not had important implications on soil water content, contrary to observed in WR. The same dynamic was observed in the CV%. Among all tested methods the most accurate to interpolate SM, in the control plot IDW 1 and in the burned plot IDW 2, and this means that fire did not induce important inferences on the spatial distribution of SM. In WR, in the control plot, the best predictor was NCS and in the burned plot was IDW 1 and this means that spatial distribution WR was substantially affected by fire. In this case we observed an increase of the small scale variability in the burned area. Currently we are monitoring this burned area and observing the evaluation of the spatial variability of these two soil properties. It is important to observe their dynamic in the space and time and observe if fire will have medium and long term implications on SM and WR. Discussions about the results will be carried out during the poster session.

Can Butterflies Evade Fire? Pupa Location and Heat Tolerance in Fire Prone Habitats of Florida

PubMed Central

Thom, Matthew D.; Daniels, Jaret C.; Kobziar, Leda N.; Colburn, Jonathan R.

2015-01-01

Butterflies such as the atala hairstreak, Eumaeus atala Poey, and the frosted elfin, Callophrys irus Godart, are restricted to frequently disturbed habitats where their larval host plants occur. Pupae of these butterflies are noted to reside at the base of host plants or in the leaf litter and soil, which may allow them to escape direct mortality by fire, a prominent disturbance in many areas they inhabit. The capacity of these species to cope with fire is a critical consideration for land management and conservation strategies in the locations where they are found. Survival of E. atala pupae in relation to temperature and duration of heat pulse was tested using controlled water bath experiments and a series of prescribed fire field experiments. Survival of E. atala pupae was correlated to peak temperature and heat exposure in both laboratory and field trials. In addition, E. atala survival following field trials was correlated to depth of burial; complete mortality was observed for pupae at the soil surface. Fifty percent of E. atala survived the heat generated by prescribed fire when experimentally placed at depths ≥ 1.75cm, suggesting that pupation of butterflies in the soil at depth can protect from fatal temperatures caused by fire. For a species such as E. atala that pupates above ground, a population reduction from a burn event is a significant loss, and so decreasing the impact of prescribed fire on populations is critical. PMID:26016779

Can butterflies evade fire? Pupa location and heat tolerance in fire prone habitats of Florida.

PubMed

Thom, Matthew D; Daniels, Jaret C; Kobziar, Leda N; Colburn, Jonathan R

2015-01-01

Butterflies such as the atala hairstreak, Eumaeus atala Poey, and the frosted elfin, Callophrys irus Godart, are restricted to frequently disturbed habitats where their larval host plants occur. Pupae of these butterflies are noted to reside at the base of host plants or in the leaf litter and soil, which may allow them to escape direct mortality by fire, a prominent disturbance in many areas they inhabit. The capacity of these species to cope with fire is a critical consideration for land management and conservation strategies in the locations where they are found. Survival of E. atala pupae in relation to temperature and duration of heat pulse was tested using controlled water bath experiments and a series of prescribed fire field experiments. Survival of E. atala pupae was correlated to peak temperature and heat exposure in both laboratory and field trials. In addition, E. atala survival following field trials was correlated to depth of burial; complete mortality was observed for pupae at the soil surface. Fifty percent of E. atala survived the heat generated by prescribed fire when experimentally placed at depths ≥ 1.75 cm, suggesting that pupation of butterflies in the soil at depth can protect from fatal temperatures caused by fire. For a species such as E. atala that pupates above ground, a population reduction from a burn event is a significant loss, and so decreasing the impact of prescribed fire on populations is critical.

Effect of Wildfire on Sequoiadendron giganteum Growth and CO2 Flux

NASA Astrophysics Data System (ADS)

Barwegen, S.

2016-12-01

Due to global warming, parts of the United States are becoming drier than ever before. In 2015, we surpassed 9 million acres burned by wildfires nationally (Rice 2015). Wildfires are most common in the Western United States due to drought, and the fact that the summer months are drier than other areas such as the East Coast, so there is a higher risk for wildland fires (Donegan 2016). These high-growth forests that are more frequently burned by wildfires each year are located near mountain ranges on the west side of the United States. They are important to tourism, contain many endangered species, and need to maintain the natural cycle of fire and regrowth for the continued success of the native plant life. This project investigated the effect of burnt soil on Sequoiadendron giganteum trees. Three were grown in burnt potting soil that had been roasted over a grill for 45 minutes (which is the average destructive fire time), and the other three were the control group in unburned potting soil. We assessed growth by measuring height, color, photosynthetically active radiation (PAR), and CO2 flux to evaluate the health of the trees in the two soil conditions. We noted that after two weeks the trunks of the trees growing in burnt soil began to brown in color, and they lost leaves. Over the course of the experiment, the trees growing in burnt soil had reduced levels of photosynthesis as compared to the unburned soil (as measured by the net change in CO2 concentration in a sealed chamber over the course of fifteen minutes intervals). On average, the trees growing in burnt soil had flux rates that were 19.59 ppm CO2 /min. more than those growing in unburned soil. In the dark reactions, the burnt soil flux was 54.5 ppm CO2/min., while the unburned soil averaged 40.5 ppm CO2/min. Our results help quantify the impact of fire on delicate ecosystems that are experiencing an increase in fire activity caused by global warming.

Forest restoration as a strategy to mitigate climate impacts on wildfire, vegetation, and water in semi-arid forests of the southwestern U.S.

NASA Astrophysics Data System (ADS)

O'Donnell, F. C.; Flatley, W. T.; Masek Lopez, S.; Fulé, P. Z.; Springer, A. E.

2017-12-01

Climate change and fire suppression are interacting to reduce forest health, drive high-intensity wildfires, and potentially reduce water quantity and quality in high-elevation forests of the southwestern US. Forest restoration including thinning and prescribed fire, is a management approach that reduces fire risk. It may also improve forest health by increasing soil moisture through the combined effects of increased snow pack and reduced evapotranspiration (ET), though the relative importance of these mechanisms is unknown. It is also unclear how small-scale changes in the hydrologic cycle will scale-up to influence watershed dynamics. We conducted field and modeling studies to investigate these issues. We measured snow depth, snow water equivalent (SWE), and soil moisture at co-located points in paired restoration-control plots near Flagstaff, AZ. Soil moisture was consistently higher in restored plots across all seasons. Snow depth and SWE were significantly higher in restored plots immediately after large snow events with no difference one week after snowfall, suggesting that restoration leads to both increased accumulation and sublimation. At the point scale, there was a small (ρ=0.28) but significant correlation between fall-to-spring soil moisture increase and peak SWE during the winter. Consistent with previous studies, soil drying due to ET was more rapid in recently restored sites than controls, but there was no difference 10 years after restoration. In addition to the small role played by snow and ET, we also observed more rapid soil moisture loss in the 1-2 days following rain or rapid snowmelt in control than in restoration plots. We hypothesize that this is due to a loss of macropores when woody plants are replaced by herbaceous vegetation and warrants further study. To investigate watershed-scale dynamics, we combined spatially-explicit vegetation and fire modeling with statistical water and sediment yield models for a large forested landscape on the Kaibab Plateau, AZ. Our results predicted that climate-induced vegetation changes will result in annual runoff declines of 2%-10% in the next century, but that restoration reversed these declines. We also predict that restoration treatments will protect water quality by reducing the incidence of high severity fire and the associated erosion.

Effects of fire frequency on litter decomposition as mediated by changes to litter chemistry and soil environmental conditions.

PubMed

Ficken, Cari D; Wright, Justin P

2017-01-01

Litter quality and soil environmental conditions are well-studied drivers influencing decomposition rates, but the role played by disturbance legacy, such as fire history, in mediating these drivers is not well understood. Fire history may impact decomposition directly, through changes in soil conditions that impact microbial function, or indirectly, through shifts in plant community composition and litter chemistry. Here, we compared early-stage decomposition rates across longleaf pine forest blocks managed with varying fire frequencies (annual burns, triennial burns, fire-suppression). Using a reciprocal transplant design, we examined how litter chemistry and soil characteristics independently and jointly influenced litter decomposition. We found that both litter chemistry and soil environmental conditions influenced decomposition rates, but only the former was affected by historical fire frequency. Litter from annually burned sites had higher nitrogen content than litter from triennially burned and fire suppression sites, but this was correlated with only a modest increase in decomposition rates. Soil environmental conditions had a larger impact on decomposition than litter chemistry. Across the landscape, decomposition differed more along soil moisture gradients than across fire management regimes. These findings suggest that fire frequency has a limited effect on litter decomposition in this ecosystem, and encourage extending current decomposition frameworks into disturbed systems. However, litter from different species lost different masses due to fire, suggesting that fire may impact decomposition through the preferential combustion of some litter types. Overall, our findings also emphasize the important role of spatial variability in soil environmental conditions, which may be tied to fire frequency across large spatial scales, in driving decomposition rates in this system.

Effects of fire frequency on litter decomposition as mediated by changes to litter chemistry and soil environmental conditions

PubMed Central

Wright, Justin P.

2017-01-01

Litter quality and soil environmental conditions are well-studied drivers influencing decomposition rates, but the role played by disturbance legacy, such as fire history, in mediating these drivers is not well understood. Fire history may impact decomposition directly, through changes in soil conditions that impact microbial function, or indirectly, through shifts in plant community composition and litter chemistry. Here, we compared early-stage decomposition rates across longleaf pine forest blocks managed with varying fire frequencies (annual burns, triennial burns, fire-suppression). Using a reciprocal transplant design, we examined how litter chemistry and soil characteristics independently and jointly influenced litter decomposition. We found that both litter chemistry and soil environmental conditions influenced decomposition rates, but only the former was affected by historical fire frequency. Litter from annually burned sites had higher nitrogen content than litter from triennially burned and fire suppression sites, but this was correlated with only a modest increase in decomposition rates. Soil environmental conditions had a larger impact on decomposition than litter chemistry. Across the landscape, decomposition differed more along soil moisture gradients than across fire management regimes. These findings suggest that fire frequency has a limited effect on litter decomposition in this ecosystem, and encourage extending current decomposition frameworks into disturbed systems. However, litter from different species lost different masses due to fire, suggesting that fire may impact decomposition through the preferential combustion of some litter types. Overall, our findings also emphasize the important role of spatial variability in soil environmental conditions, which may be tied to fire frequency across large spatial scales, in driving decomposition rates in this system. PMID:29023560

Effects of dormant- vs. growing-season fire in shortgrass steppe: Biological soil crust and perennial grass responses

Treesearch

P. L. (Paulette) Ford; G. V. Johnson

2006-01-01

This research experimentally examined seasonal effects of fire on biological soil crusts and perennial grasses in shortgrass steppe. We predicted dormant-season fire would have greater negative effects on biological soil crusts than fire during the growing season, but less of an impact on perennial grasses than fire during the growing season. Treatments were dormant-...

Quantifying soil burn severity for hydrologic modeling to assess post-fire effects on sediment delivery

NASA Astrophysics Data System (ADS)

Dobre, Mariana; Brooks, Erin; Lew, Roger; Kolden, Crystal; Quinn, Dylan; Elliot, William; Robichaud, Pete

2017-04-01

Soil erosion is a secondary fire effect with great implications for many ecosystem resources. Depending on the burn severity, topography, and the weather immediately after the fire, soil erosion can impact municipal water supplies, degrade water quality, and reduce reservoirs' storage capacity. Scientists and managers use field and remotely sensed data to quickly assess post-fire burn severity in ecologically-sensitive areas. From these assessments, mitigation activities are implemented to minimize post-fire flood and soil erosion and to facilitate post-fire vegetation recovery. Alternatively, land managers can use fire behavior and spread models (e.g. FlamMap, FARSITE, FOFEM, or CONSUME) to identify sensitive areas a priori, and apply strategies such as fuel reduction treatments to proactively minimize the risk of wildfire spread and increased burn severity. There is a growing interest in linking fire behavior and spread models with hydrology-based soil erosion models to provide site-specific assessment of mitigation treatments on post-fire runoff and erosion. The challenge remains, however, that many burn severity mapping and modeling products quantify vegetation loss rather than measuring soil burn severity. Wildfire burn severity is spatially heterogeneous and depends on the pre-fire vegetation cover, fuel load, topography, and weather. Severities also differ depending on the variable of interest (e.g. soil, vegetation). In the United States, Burned Area Reflectance Classification (BARC) maps, derived from Landsat satellite images, are used as an initial burn severity assessment. BARC maps are classified from either a Normalized Burn Ratio (NBR) or differenced Normalized Burned Ratio (dNBR) scene into four classes (Unburned, Low, Moderate, and High severity). The development of soil burn severity maps requires further manual field validation efforts to transform the BARC maps into a product more applicable for post-fire soil rehabilitation activities. Alternative spectral indices and modeled output approaches may prove better predictors of soil burn severity and hydrologic effects, but these have not yet been assessed in a model framework. In this project we compare field-verified soil burn severity maps to satellite-derived and modeled burn severity maps. We quantify the extent to which there are systematic differences in these mapping products. We then use the Water Erosion Prediction Project (WEPP) hydrologic soil erosion model to assess sediment delivery from these fires using the predicted and observed soil burn severity maps. Finally, we discuss differences in observed and predicted soil burn severity maps and application to watersheds in the Pacific Northwest to estimate post-fire sediment delivery.

The ash in forest fire affected soils control the soil losses. Part 2. Current and future research challenges

NASA Astrophysics Data System (ADS)

Pereira, Paulo; Cerdà, Artemi

2013-04-01

Ash distribution on soil surface and impacts on soil properties received a great attention in recently (Pereira et al., 2010; Pereira et al., 2013). Ash it is a highly mobile material that can be easily transported wind, especially in severe wildland fires, where organic matter is reduced to dust, due the high temperatures of combustion. In the immediate period after the fire, ash cover rules soil erosion as previous researchers observed (Cerdà, 1998a; 1998b) and have strong influence on soil hydrological properties, such as water retention (Stoof et al. 2011 ) and wettability (Bodi et al., 2011). Ash it is also a valuable source of nutrients important for plant recuperation (Pereira et al., 2011; Pereira et al., 2012), but can act also as a source contamination, since are also rich in heavy metals (Pereira and Ubeda, 2010). Ash has different physical and chemical properties according the temperature of combustion, burned specie and time of exposition (Pereira et al., 2010). Thus this different properties will have different implications on soil properties including erosion that can increase due soil sealing (Onda et al. 2008) or decrease as consequence of raindrop impact reduction (Cerdà and Doerr, 2008). The current knowledge shows that ash has different impacts on soil properties and this depends not only from the type of ash produced, but of the soil properties (Woods and Balfour, 2010). After fire wind and water strong redistribute ash on soil surface, increasing the vulnerability of soil erosion in some areas, and reducing in others. Understand this mobility is fundamental have a better comprehension about the spatial and temporal effects of ash in soil erosion. Have a better knowledge about this mobility is a priority to future research. Other important aspects to have to be assessed in the future are how ash particulates percolate on soil and how ash chemical composition is important to induce soil aggregation and dispersion. How soil micro topography have implications on ash spatial distribution and if soil micro topography changes with time? What the factors that controls it? What it is the impact of ash in vegetation recuperation and the implications of this recover in ash spatial distribution? We need studies with better spatial and temporal resolution, especially in the immediate period after the fire, when the major spatial and temporal changes on ash distribution and impacts occur. Based on high level research conducted by Artemi Cerdà and others, our future research will be focused in these and other aspects in order to have a better knowledge about the impacts of ash on post-fire spatio-temporal erosion. Acknowledgements, Lithuanian Research Council. Project LITFIRE, Fire effects on Lithuanian soils and ecosystems (MIP-48/2011) and the research projects GL2008-02879/BTE and LEDDRA 243857. References Bodí, M., Mataix-Solera, J., Doerr, S., and Cerdà, A. 2011b. The wettability of ash from burned vegetation and its relationship to Mediterranean plant species type, burn severity and total organic carbon content. Geoderma, 160, 599-607. Cerdà, A. 1998a. Postfire dynamics of erosional processes under mediterranean climatic conditions. Z. Geomorphol., 42 (3) 373-398. Cerdà, A. 1998b. Changes in overland flow and infiltration after a rangeland fire in a Mediterranean scrubland.Hydrological Processes, 12, 1031-1042. Cerdà, A., and Doerr, S.H. 2008. The effect of ash and needle cover on surface runoff and erosion in the immediate post-fire period. Catena, 74, 256-263. Onda, Y., Dietrich W. E., and Booker, F. 2008. Evolution of overland flow after severe forest fire, Point Reyes, California, Catena, 72, 13-20. Pereira, P. Cerdà, A., Úbeda, X., Mataix-Solera, J. Arcenegui, V., Zavala, L. 2013. Modelling the impacts of wildfire on ash thickness in a short-term period, Land Degradation and Development, (In press) Pereira, P., Bodi. M., Úbeda, X., Cerdà, A., Mataix-Solera, J., Balfour, V, Woods, S. 2010. Las cenizas y el ecosistema suelo, In: Cerdà, A. Jordan, A. (eds) Actualización en métodos y técnicas para el estudio de los suelos afectados por incendios forestales, 345-398. Càtedra de Divulgació de la Ciència. Universitat de Valencia. ISBN: 978-84-370-7887-8. Deposito Legal: V-3541-2010. Pereira, P., Úbeda, X. 2010. Spatial variation of heavy metals released from ashes after a wildfire, Journal of Environmental Engineering and Landscape Management, 18(1), 13-22. Pereira, P., Ubeda, X., Martin, D. 2012. Fire severity effects on ash chemical composition and water-extractable elements, Geoderma, 191, 105-114. Pereira, P., Úbeda, X., Martin, D., Mataix-Solera, J., Guerrero, C. 2011. Effects of a low prescribed fire in ash water soluble elements in a Cork Oak (Quercus suber) forest located in Northeast of Iberian Peninsula, Environmental Research, 111(2), 237-247. Stoff, C.R., Wesseling, J.G., Ritsema, C.J. 2011. Effects of ash on soil water retention, Geoderma, 159(3-4), 276-285. Woods, S.W., Balfour, V.N. 2010. The effects of soil texture and ash thickness on the post-fire hydrological response from ash-covered soils, Journal of Hydrology, 393, 274-286.

Test Plan to Assess Fire Effects on the Function of an Engineered Surface Barrier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ward, Anderson L.; Berlin, Gregory T.; Cammann, Jerry W.

2008-09-29

Wildfire is a frequent perturbation in shrub steppe ecosystems, altering the flora, fauna, atmosphere, and soil of these systems. Research on the fire effects has focused mostly on natural ecosystems with essentially no attention on engineered systems like surface barriers. The scope of the project is to use a simulated wildfire to induce changes in an engineered surface barrier and document the effects on barrier performance. The main objective is to quantify the effects of burning and the resulting post-fire conditions on alterations in soil physical properties; hydrologic response, particularly the water balance; geochemical properties; and biological properties. A secondarymore » objective is to use the lessons learned to maximize fire protection in the design of long-term monitoring systems based on electronic sensors. A simulated wildfire will be initiated, controlled and monitored at the 200-BP-1 barrier in collaboration with the Hanford Fire Department during the fall of 2008. The north half of the barrier will be divided into nine 12 x 12 m plots, each of which will be randomly assigned a fuel load of 2 kg m-2 or 4 kg m-2. Each plot will be ignited around the perimeter and flames allowed to carry to the centre. Any remaining unburned vegetation will be manually burned off using a drip torch. Progress of the fire and its effects will be monitored using point measurements of thermal, hydrologic, and biotic variables. Three measures of fire intensity will be used to characterize fire behavior: (1) flame height, (2) the maximum temperature at three vertical profile levels, and (3) total duration of elevated temperature at these levels. Pre-burn plant information, including species diversity, plant height, and canopy diameter will be measured on shrubs from the plots to be burned and from control plots at the McGee ranch. General assessments of shrub survival, recovery, and recruitment will be made after the fire. Near-surface soil samples will be collected pre- and post-burn to determine changes in the gravel content of the surface layer so as to quantify inflationary or deflationary responses to fire and to reveal the ability of the surface to resist post-fire erosive stresses. Measures of bulk density, water repellency, water retention, and hydraulic conductivity will be used to characterize changes in infiltration rates and water storage capacity following the fire. Samples will also be analyzed to quantify geochemical changes including changes in soil pH, cation exchange capacity, specific surface area, and the concentration of macro nutrients (e.g. N, P, K) and other elements such as Na, Mg, Ca, that are critical to the post-fire recovery revegetation. Soil CO2 emissions will be measured monthly for one year following the burn to document post-fire stimulation of carbon turnover and soil biogenic emissions. Surface and subsurface temperature measurements at and near monitoring installations will be used to document fire effects on electronic equipment. The results of this study will be used to bridge the gaps in knowledge on the effects of fire on engineered ecosystems (e.g. surface barriers), particularly the hydrologic and biotic characteristics that govern the water and energy balance. These results will also support the development of practical fire management techniques for barriers that are compatible with wildfire suppression strategies. Furthermore, lessons learned will be use to develop installation strategies needed to protect electronic monitoring equipment from the intense heat of fire and the potential damaging effects of smoke and fire extinguishing agents. Such information is needed to better understand long-term barrier performance under extreme conditions, especially if site maintenance and operational funding is lost for activities such as barrier revegetation.« less

Testing the effectiveness of pine needlecast in reducing post-fire soil erosion using complementary experimental approaches

NASA Astrophysics Data System (ADS)

Bento, C. P. M.; Shakesby, R. A.; Walsh, R. P. D.; Ferreira, C. S. S.; Ferreira, A. J. D.; Urbanek, E.

2012-04-01

Mediterranean wildfire activity has increased markedly in recent decades, leading to enhanced runoff and erosion. Limiting post-fire on-site soil degradation and off-site flooding and sedimentation, however, often has a low priority because of the high costs of materials and labour needed to implement many recognised techniques (e.g. seeding, hydromulching, installing logs along the contour). However, in pine plantations, the crowns may only be scorched so that after fire the needlecast can form a comparatively dense ground cover. Its post-fire erosion-limiting effectiveness is virtually unknown in the Mediterranean context, despite potentially protecting soil with minimal effort (requiring only a delay to existing salvage logging procedures at most). As part of the DESIRE research programme, this paper presents results from two complementary approaches testing the erosion-limiting effectiveness of needlecast. (1) Near Moinhos, central Portugal, two 8m2 erosion plots were established immediately post-fire in September 2009 on a steep (30°) slope representative of an adjacent burnt Pinus pinaster plantation. Soil erosion was monitored during a 3-month pre-treatment phase. Needles were then applied to one plot at a density (37.7% cover) measured on a post-fire pine plantation. Soil losses from treated and untreated plots were then monitored until April 2011. By taking the percentage increase or decrease in erosion between the two monitoring phases for the untreated control plot as the 'expected' pattern, the erosion-limiting effectiveness of needles applied to the treated plot could then be determined. (2) Six adjacent rectangular 1.23m2 lysimeters were filled with gravel and sand, and capped by 10 cm of topsoil taken from a long unburnt Pinus pinaster plantation. They were set at 15° and left open to natural rainfall. This angle was considered the steepest possible from logistical and soil stability points of view. All lysimeters underwent a phase under bare soil conditions. In a second phase, a representative amount (8.34 kg) of fermented litter and shrubs from a pine plantation was applied evenly to each of five lysimeters. In a third stage, four of the five treated lysimeters were burned to simulate a low-severity wildfire. After several more rainfall events, pine needles (37.7% cover) were applied to two of the burnt lysimeters. In the final stage, there was 1 lysimeter with bare soil, 1 unburnt with a vegetation cover, 2 burnt and untreated, and 2 burnt with needles. In all the lysimeters, runoff and percolated water were monitored during the entire study, as were the amounts of eroded sediment and organic matter contents for runoff. Calculating the erosion-limiting effect of needles was conducted in a similar fashion to (1) and based on results from stages 3 and 4. The results from both experiments show that the needles reduced erosion by as much as c.60% compared with the corresponding control situation, indicating that a needlecast 'carpet' is likely to be able to provide a highly effective, simple, cheap means of significantly reducing post-fire soil loss in pine forests where the tree canopies have been scorched but not consumed by fire.

Fire Severity and Soil Carbon Combustion in Boreal and Tundra Ecosystems

NASA Astrophysics Data System (ADS)

Walker, X. J.; Mack, M. C.; Baltzer, J. L.; Cummings, S.; Day, N.; Goetz, S.; Johnstone, J. F.; Rogers, B. M.; Turetsky, M. R.

2016-12-01

Climate warming in northern latitudes has led to an intensification of wildfire disturbance. Increased fire frequency, extent, and severity is expected to strongly impact the structure and function of northern ecosystems. In this study, we examined 50 sites in a recently burned tundra ecosystem of Alaska, USA and 250 sites in recently burned boreal conifer forest ecosystems of Northwest Territories, Canada. The majority of organic carbon (C) in both boreal and tundra ecosystems resides in the soil organic layer (SOL) and combustion of this layer can lead to large C emissions. Through examining multiple fire scars in different regions, ranging in moisture, elevation, and pre-fire vegetation communities, we can determine the ecosystem, landscape, and regional controls on SOL combustion and the potential shift in C storage. In this research, we use scalable SOL consumption metrics to estimate depth of burn and the associated C emissions. Preliminary results from boreal conifer sites indicate that nearly 50% of the pre-fire soil C pool was combusted and that over 75% of the total C emitted from the extreme fire year of 2014 can be attributed to combustion of the SOL. Increased combustion of SOL associated with an intensifying fire regime could shift boreal and tundra ecosystems across a C cycle threshold: from net accumulation of C from the atmosphere over multiple fire cycles, to a net loss. Understanding changes in SOL combustion and C storage is essential for assessing the consequences of an altered fire regime on permafrost dynamics, vegetation regeneration, and the initiation of successional trajectories in tundra and boreal ecosystems.

Available nitrogen: A time-based study of manipulated resource islands

USGS Publications Warehouse

Stubbs, Michelle M.; Pyke, David A.

2005-01-01

Spatial and temporal heterogeneity of available nitrogen are critical determinants of the distribution and abundance of plants and animals in ecosystems. Evidence for the resource island theory suggests that soils below tree and shrub canopies contain higher amounts of resources, including available nitrogen, than are present in interspace areas. Disturbances, such as prescribed fire and tree removal, are common management practices in shrub-woodland ecosystems, but it is not known if these practices affect resource islands. We examined temporal variation in resource islands of available nitrogen and their retention after fire and woody plant removal. From August 1997 to October 1998, soil nitrate (NO3−) and ammonium (NH4+) were measured monthly from canopy and interspace plots within four juniper-sagebrush sites along a precipitation gradient in central Oregon, USA. At each site, soil samples were collected from untreated plots, plots in which woody plants were removed, and those treated with prescribed fire in fall 1997. In burned treatments, canopy concentrations were significantly higher than interspace concentrations throughout the measurement period. Canopy NO3− and NH4+ concentrations were significantly higher on burned vs. unburned treatments for four months after fire. After woody plant removal, NO3− and NH4+ concentrations did not differ from the controls. Untreated control areas had higher NO3− and NH4+ concentrations under juniper canopies for nearly all months. Wetter sites had smaller differences between canopy and interspace concentrations through time than did the two drier sites. In relation to NO3− and NH4+ in this ecosystem, resource islands appear to be more ephemeral in wetter sites, and more pronounced following fire disturbances than in controls or those treated by woody plant removal.

The effects of fire severity on black carbon additions to forest soils - 10 years post fire

NASA Astrophysics Data System (ADS)

Poore, R.; Wessman, C. A.; Buma, B.

2013-12-01

Wildfires play an active role in the global carbon cycle. While large amounts of carbon dioxide are released, a small fraction of the biomass consumed by the fire is only partially combusted, yielding soot and charcoal. These products, also called black carbon (BC) make up only 1-5% of the biomass burnt, yet they can have a disproportionate effect on both the atmosphere and fluxes in long-term carbon pools. This project specifically considers the fraction that is sequestered in forest soils. Black carbon is not a specific compound, and exists along a continuum ranging from partially burned biomass to pure carbon or graphite. Increasing aromaticity as the result of partial combustion means charcoal is highly resistant to oxidation. Although debated, most studies indicate a turnover time on the order of 500-1,000 years in warm, wet, aerobic soils. Charcoal may function as a long-term carbon sink, however its overall significance depends on its rate of formation and loss. At the landscape level, fire characteristics are one of the major factors controlling charcoal production. A few studies suggest that charcoal production increases with cooler, less-severe fires. However, there are many factors to tease apart, partly because of a lack of specificity in how fire severity is defined. Within this greater context, our lab has been working on a landscape-level study within Routt National Forest, north of Steamboat Springs, Colorado. In 2002, a large fire swept through a subalpine spruce, fir and lodgepole pine forest. In 2011-2013 we sampled BC pools in 44 plots across a range of fire severities from unburned to severe crown We hypothesized that charcoal stocks will be higher in areas of low severity fire as compared to high severity because of decreased re-combustion of charcoal in the organic soil and increased overall charcoal production due to lower temperatures. In each of our plots we measured charcoal on snags and coarse woody debris, sampled the entire organic horizon and the top 10cm mineral horizon. The soils were sieved to 2mm and their BC content measured using the Kurth-MacKenzie-DeLuca method of digesting labile carbon using nitric acid and hydrogen peroxide at 95C for 20hrs. We integrated both remotely sensed data and field observations. We used the Relative Difference Normalized Burn Ratio (RdNBR) calculated by Monitoring Trends in Burn Severity (MTBS). This index used Landsat images from July in the years before and after the fire and is based on differences in bands 4 and 7, with the aim of assessing coarse scale changes in soil and vegetation post fire. For each plot we also collected data on tree mortality and organic soil depth. These metrics were chosen from the Composite Burn Index as those that were most reliable even 10 years after the fire. We observed no significant differences in BC totals between high severity fire and unburned plots, although BC increased slightly on burned plots. Early results for low severity sites (analysis still in progress) suggest that BC increased in plots experiencing lower severity fires compared to unburned and high severity plots. Comparing carbon and BC totals on unburned and severely burned plots, and assuming no loss of BC from mineral soil during the fire, we observed a 1.2% conversion of burned biomass to BC, which corresponds with literature estimates of 1-4%.

Fire as a control agent of demographic structure and plant performance of a rare Mediterranean endemic geophyte.

PubMed

Diadema, Katia; Médail, Frédéric; Bretagnolle, François

2007-09-01

We examine the effects of fire and/or surrounding vegetation cover on demographic stage densities and plant performance for a rare endemic geophyte, Acis nicaeensis (Alliaceae), in Mediterranean xerophytic grasslands of the 'Alpes-Maritimes' French 'département', through sampling plots in unburned and burned treatments. Fire increases density of flowering individuals and seedling emergence, as well as clump densities and number of individuals per clump, per limiting vegetation height and cover, and increasing bare soil cover. In contrast, fire has no effect on reproductive success. Nevertheless, two growing seasons after fire, all parameters of demographic stages and plant performance do not significantly differ between the two treatments. Small-scale fire is beneficial for the regeneration of this threatened geophyte at a short-time scale. In this context, a conservation planning with small and controlled fires could maintain the regeneration window for populations of rare Mediterranean geophytes.

Soil Methane Sink Capacity Response to a Long-Term Wildfire Chronosequence in Northern Sweden.

PubMed

McNamara, Niall P; Gregg, Ruth; Oakley, Simon; Stott, Andy; Rahman, Md Tanvir; Murrell, J Colin; Wardle, David A; Bardgett, Richard D; Ostle, Nick J

2015-01-01

Boreal forests occupy nearly one fifth of the terrestrial land surface and are recognised as globally important regulators of carbon (C) cycling and greenhouse gas emissions. Carbon sequestration processes in these forests include assimilation of CO2 into biomass and subsequently into soil organic matter, and soil microbial oxidation of methane (CH4). In this study we explored how ecosystem retrogression, which drives vegetation change, regulates the important process of soil CH4 oxidation in boreal forests. We measured soil CH4 oxidation processes on a group of 30 forested islands in northern Sweden differing greatly in fire history, and collectively representing a retrogressive chronosequence, spanning 5000 years. Across these islands the build-up of soil organic matter was observed to increase with time since fire disturbance, with a significant correlation between greater humus depth and increased net soil CH4 oxidation rates. We suggest that this increase in net CH4 oxidation rates, in the absence of disturbance, results as deeper humus stores accumulate and provide niches for methanotrophs to thrive. By using this gradient we have discovered important regulatory controls on the stability of soil CH4 oxidation processes that could not have not been explored through shorter-term experiments. Our findings indicate that in the absence of human interventions such as fire suppression, and with increased wildfire frequency, the globally important boreal CH4 sink could be diminished.

Soil Methane Sink Capacity Response to a Long-Term Wildfire Chronosequence in Northern Sweden

PubMed Central

McNamara, Niall P.; Gregg, Ruth; Oakley, Simon; Stott, Andy; Rahman, Md. Tanvir; Murrell, J. Colin; Wardle, David A.; Bardgett, Richard D.; Ostle, Nick J.

2015-01-01

Boreal forests occupy nearly one fifth of the terrestrial land surface and are recognised as globally important regulators of carbon (C) cycling and greenhouse gas emissions. Carbon sequestration processes in these forests include assimilation of CO2 into biomass and subsequently into soil organic matter, and soil microbial oxidation of methane (CH4). In this study we explored how ecosystem retrogression, which drives vegetation change, regulates the important process of soil CH4 oxidation in boreal forests. We measured soil CH4 oxidation processes on a group of 30 forested islands in northern Sweden differing greatly in fire history, and collectively representing a retrogressive chronosequence, spanning 5000 years. Across these islands the build-up of soil organic matter was observed to increase with time since fire disturbance, with a significant correlation between greater humus depth and increased net soil CH4 oxidation rates. We suggest that this increase in net CH4 oxidation rates, in the absence of disturbance, results as deeper humus stores accumulate and provide niches for methanotrophs to thrive. By using this gradient we have discovered important regulatory controls on the stability of soil CH4 oxidation processes that could not have not been explored through shorter-term experiments. Our findings indicate that in the absence of human interventions such as fire suppression, and with increased wildfire frequency, the globally important boreal CH4 sink could be diminished. PMID:26372346

Edaphic and microclimatic controls over permafrost response to fire in interior Alaska

Treesearch

D.R. Nossov; M.T. Jorgenson; K. Kielland; M. Kanevskiy

2013-01-01

Discontinuous permafrost in the North American boreal forest is strongly influenced by the effects of ecological succession on the accumulation of surface organic matter, making permafrost vulnerable to degradation resulting from fire disturbance. To assess factors affecting permafrost degradation after wildfire, we compared vegetation composition and soil properties...

Predicting large wildfires across western North America by modeling seasonal variation in soil water balance.

PubMed

Waring, Richard H; Coops, Nicholas C

A lengthening of the fire season, coupled with higher temperatures, increases the probability of fires throughout much of western North America. Although regional variation in the frequency of fires is well established, attempts to predict the occurrence of fire at a spatial resolution <10 km 2 have generally been unsuccessful. We hypothesized that predictions of fires might be improved if depletion of soil water reserves were coupled more directly to maximum leaf area index (LAI max ) and stomatal behavior. In an earlier publication, we used LAI max and a process-based forest growth model to derive and map the maximum available soil water storage capacity (ASW max ) of forested lands in western North America at l km resolution. To map large fires, we used data products acquired from NASA's Moderate Resolution Imaging Spectroradiometers (MODIS) over the period 2000-2009. To establish general relationships that incorporate the major biophysical processes that control evaporation and transpiration as well as the flammability of live and dead trees, we constructed a decision tree model (DT). We analyzed seasonal variation in the relative availability of soil water ( fASW ) for the years 2001, 2004, and 2007, representing respectively, low, moderate, and high rankings of areas burned. For these selected years, the DT predicted where forest fires >1 km occurred and did not occur at ~100,000 randomly located pixels with an average accuracy of 69 %. Extended over the decade, the area predicted burnt varied by as much as 50 %. The DT identified four seasonal combinations, most of which included exhaustion of ASW during the summer as critical; two combinations involving antecedent conditions the previous spring or fall accounted for 86 % of the predicted fires. The approach introduced in this paper can help identify forested areas where management efforts to reduce fire hazards might prove most beneficial.

Fire as a Factor of Variation of Soil Respiration in Amazonia of Peru

NASA Astrophysics Data System (ADS)

Suarez, L.; Kruijt, B.

2007-05-01

Severe changes are affecting the role of Amazonia in the Earth system. One of these possible effects could be the modification of the relevance of soil in the carbon cycle. In this sense, fire is an important factor for mobilizing C from the soil to the atmosphere, mainly as CO2. This could have an important effect in the global warming. Our proposal will evaluate the variation of the soil respiration related to the seasonality and the fire effects on soils in the Amazonia of Peru and Brasil. In experimental parcels of four locations of Peru with different vegetation cover (forest and pasture), we will measure soil respiration along with the organic carbon and the microbial biomass of soils during campaigns of wet and dry seasons, with complementary measurements of soil temperature, water and nutrient content. Also, we will reproduce a fire experiment simulating local activity of "slash and burn" to evaluate fire effects. Measurements will be taken after the soil cooled and 1, 3, 5, 7 and 10 days after the fire. Additionally, the carbon stock of the subparcels will be evaluated. Evaluation of the variations of CO2 fluxes and the capacity of adaptation to fire and water content will be done through the comparisons of the different locations, type of soils and concentration of available N as an indicator of nutrient content.

Effect of fire on soil physical and chemical properties in a Mediterranean area of Sardinia.

NASA Astrophysics Data System (ADS)

Canu, Annalisa; Motroni, Andrea; Arca, Bachisio; Pellizzaro, Grazia; Ventura, Andrea; Secci, Romina; Robichaud, Peter

2014-05-01

Wildfires are one of the most widespread factors of ecosystem degradation around the world. The degree of change in both chemical and biological properties of soil inducted by forest fires is related to temperature and persistence of the fire as well as to moisture content of soil and of fuel. The present note reports the first experimental results of a wider-scale research project, whose aim is to develop methods for analysis and collection of field data by using a multidisciplinary approach in order to evaluate land erosion hazard. Specific objectives of this study are: i) to compare burned and unburned soil in order to evaluate the effect of fire on physical and chemical soil properties; ii) to measure soil erosion after fire in relation to different slopes. The experimental site is located in Mediterranean basin, on a steep slope in a hilly area of north-western Sardinia (Municipality of Ittiri, Italy), where a human caused fire occurred in august 2013. The area is mainly covered by the typical Mediterranean vegetation. Immediately after fire, several soil samples were collected from 0-10 cm depth, both in burned and in unburned plots. The soil organic matter, N, and P contents, pH, and soil texture were then determined in laboratory. Soil erosion rates from experimental plots were measured and estimated by silt fences technique taking into account different slopes and vegetation distribution.

Short-term low-severity spring grassland fire impacts on soil extractable elements and soil ratios in Lithuania.

PubMed

Pereira, Paulo; Cerda, Artemi; Martin, Deborah; Úbeda, Xavier; Depellegrin, Daniel; Novara, Agata; Martínez-Murillo, Juan F; Brevik, Eric C; Menshov, Oleksandr; Comino, Jesus Rodrigo; Miesel, Jessica

2017-02-01

Spring grassland fires are common in boreal areas as a consequence of slash and burn agriculture used to remove dry grass to increase soil nutrient properties and crop production. However, few works have investigated fire impacts on these grassland ecosystems, especially in the immediate period after the fire. The objective of this work was to study the short-term impacts of a spring grassland fire in Lithuania. Four days after the fire we established a 400m 2 sampling grid within the burned area and in an adjacent unburned area with the same topographical, hydrological and pedological characteristics. We collected topsoil samples immediately after the fire (0months), 2, 5, 7 and 9months after the fire. We analysed soil pH, electrical conductivity (EC), major nutrients including calcium (Ca), magnesium (Mg), sodium (Na), and potassium (K), and the minor elements aluminium (Al), manganese (Mn), iron (Fe) and zinc (Zn). We also calculated the soil Na and K adsorption ratio (SPAR), Ca:Mg and Ca:Al. The results showed that this low-severity grassland fire significantly decreased soil pH, Al, and Mn but increased EC, Ca, Mg, and K,. There was no effect on Na, Fe, and Zn. There was a decrease of EC, Ca, Mg, and Na from 0months after the fire until 7months after the fire, with an increase during the last sampling period. Fire did not significantly affect SPAR. Ca:Mg decreased significantly immediately after the fire, but not to critical levels. Ca:Al increased after the fire, reducing the potential effects of Al on plants. Overall, fire impacts were mainly limited to the immediate period after the fire. Copyright © 2016 Elsevier B.V. All rights reserved.

Final Environmental Assessment for Long-Term Vegetation Control for Eglin Air Force Base, Florida

DTIC Science & Technology

2008-07-14

of vegetation typically adapted for life in saturated soil conditions” (USACE, 1987). The majority of jurisdictional wetlands in the United States...hardwood, sand pine, and titi encroachment. Longleaf Pine Sandhills consist of a high diversity of species adapted to fire and the heterogeneous...fire frequency in flatwoods is one to eight years, with nearly all of the plants and animals inhabiting this community adapted to recurrent fires

Understanding environmental drivers in the regulation of soil respiration dynamics after fire in semi-arid ecosystems

NASA Astrophysics Data System (ADS)

Muñoz-Rojas, Miriam; Lewandrowski, Wolfgang; Erickson, Todd E.; Dixon, Kingsley W.; Merritt, David J.

2016-04-01

Keywords: Pilbara, soil CO2 efflux, soil C, soil moisture, soil temperature Introduction Soil respiration (Rs) has become a major research focus given the increase in atmospheric CO2 emissions and the large contribution of these CO2 fluxes from soils (Van Groenigen et al., 2014). In addition to its importance in the global C cycle, Rs is a fundamental indicator of soil health and quality that reflects the level of microbial activity and provides an indication of the ability of soils to support plant growth (Oyonarte et al., 2012; Munoz-Rojas et al., 2015). Wildfires can have a significant impact on Rs rates, with the scale of the impact depending on environmental factors such as temperature and moisture, and organic C content in the soil. Vegetation cover can have a significant effect on regulating organic C contents; and while advances are made into understanding the effects of fire on organic C contents and CO2 fluxes (Granged et al., 2011; Willaarts et al., 2015; Muñoz-Rojas et al., 2016), there is limited knowledge of the variability of Rs across ecosystem types, vegetation communities, and responses to fire. In this research we aimed to assess the impacts of a wildfire on the soil CO2 fluxes and soil respiration in a semi-arid ecosystem of Western Australia (Pilbara biogeographical region), and to understand the main environmental drivers controlling these fluxes in different vegetation types. The study has application for other arid and semi-arid regions of the world. Methods The study area was selected following a wildfire that affected 25 ha in February 2014. Twelve plots were established in the burnt site (B) within a 400 m2 area, and 12 plots in an adjacent unburnt control site. At each site, three plots were installed below the canopy of each of the most representative vegetation types of the areas: Eucalyptus trees, Acacia shrubs and Triodia grasses, and three on bare soil. Soil sampling and measurement of soil CO2 efflux, temperature and moisture were carried out one week after wildfire in the summer-wet season (February 2014) and repeated six months (in July 2014, during the winter-dry season) and twelve months after the wildfire (in February 2015, during the following summer-wet season). Soil physicochemical analyses were undertaken according to standard methods. Rs was measured with a 6400-09 portable soil CO2 flux chamber attached to a LI-COR 6400. Soil temperature was measured with a thermometer attached to the LI-COR and soil moisture with a portable Moisture Probe MP406. Both temperature and moisture were measured directly adjacent to the collars and simultaneously with Rs at a depth of 5 cm. Results and discussion Larger rates of Rs were found in the burnt areas compared to those unburnt. However, Rs showed a large variation among vegetation types in both burnt and unburnt areas for each time period following fire and Rs and soil organic C were consistently higher under Eucalyptus trees. Environmental factors (temperature and moisture) could explain a large fraction of Rs variability and therefore the roles of both water availability and temperature are critical to explain the CO2 fluxes in these environments. Yet, these relations are variable and change across vegetation types, indicating that specific models need to be used to accurately estimate Rs rates. This study demonstrates the importance of assessing CO2 fluxes following fire considering both environmental factors and vegetation types. This is particularly important in heterogeneous semi-arid areas that are characterized by patchy vegetation distribution where CO2 fluxes can be largely underestimated. References Granged, A.J.P., Jordán, A., Zavala, L.M, Muñoz-Rojas, M., Mataix-Solera, J., 2011. Short-term effects of experimental fire for a soil under eucalyptus forest (SE Australia). Geoderma 167-168, 125-134. Muñoz-Rojas, M., Lewandrowski, W., Martini, D., Erickson, T., Merritt, D., Dixon, K. 2015. Seasonal dynamics of soil CO2 efflux in biodiverse semi-arid ecosystems of Western Australia. Geophysical Research. Abstracts Vol. 17, EGU2015-3961-1, EGU General Assembly. Muñoz-Rojas, M., Erickson, T.E., Martini, D., Dixon, K.W., Merritt, D.J. 2016. Soil physicochemical and microbiological indicators of short, medium and long term post-fire recovery in semi-arid ecosystems. Ecological indicators 63,14-22. Oyonarte, C., Rey, A., Raimundo, J., Miralles, I., Escribano, P., 2012. The use of soil respiration as an ecological indicator in arid ecosystems of the SE of Spain: spatial variability and controlling factors. Ecological Indicators 14, 40-49. Van Groenigen, K.J., Qi, X., Osenberg, C.W., Luo, Y., Hungate, B.A., 2014. Faster Decomposition under Increased Atmospheric CO2 Limits Soil Carbon Storage. Science 344, 508 Willaarts, B.A., Oyonarte, C., Muñoz-Rojas, M., Ibáñez, J.J. and Aguilera, P.A. 2015. Environmental Factors Controlling Soil Organic Carbon Stocks in Two Contrasting Mediterranean Climatic Areas of Southern Spain. Land Degradation and Development (on-line). DOI: 10.1002/ldr.2417

Changes in Fire-Derived Soil Black Carbon Storage in a Sub-humid Woodland

NASA Astrophysics Data System (ADS)

White, J. D.; Yao, J.; Murray, D. B.; Hockaday, W. C.

2014-12-01

Fire-derived black carbon (BC) in soil, including charcoal, represents a potentially important fraction of terrestrial carbon cycling due to its presumed long persistence in soil. Interpretation of site BC retention is important for assessing feedbacks to ecosystem processes including nutrient and water cycling. However, interaction between vegetation disturbance, BC formation, and off site transport may exist that complicate interpretation of BC addition to soils from wildfire or prescribed burns directly. To investigate the relationship between disturbance and site retention on soil BC, we determined BC concentrations for a woodland in central Texas, USA, from study plots in hilly terrain with a fire scar dendrochronology spanning 100 years. BC values were determined from 13C nuclear magnetic resonance (NMR) spectroscopy. Estimated values showed mean BC concentration of 2.73 ± 3.06 g BC kg-1 (0.91 ± 0.51 kg BC m-2) for sites with fire occurrence within the last 40 years compared with BC values of1.21 ± 1.70 g BC kg-1 soil (0.18 ± 0.14 kg BC m-2) for sites with fire 40 - 100 years ago. Sites with no tree ring evidence of fire during the last 100 years had the lowest mean soil BC concentration of 0.05 ± 0.11 g BC kg-1 (0.02 ± 0.03 kg BC m-2). Molecular proxies of stability (lignin/N) and decomposition (Alkyl C/O-Alky C) showed no differences across the sites, indicating that low potential for BC mineralization. Modeled soil erosion and time since fire from fire scar data showed that soil BC concentrations were inversely correlated. A modified the ecosystem process model, Biome-BGC, was also used simulate the effects of fire disturbance with different severities and seasonality on C cycling related to the BC production, effect on soil water availability, and off-site transport. Results showed that BC impacts on ecosystem processes, including net ecosystem exchange and leaf area development, were predominantly related to fire frequency. Site BC loss rates were affected by initial slope-affected erosion, fire severity, vegetation type, and rate of vegetation recovery. The simulation results showed that fire types, such as high severity, was generally associated with low site BC retention related to low vertical transfer of BC into soils, buoyancy of BC particles, and surface runoff from unvegetated soils.

Index for characterizing post-fire soil environments in temperate coniferous forests

Treesearch

Theresa B. Jain; David S. Pilliod; Russell T. Graham; Leigh B. Lentile; Jonathan E. Sandquist

2012-01-01

Many scientists and managers have an interest in describing the environment following a fire to understand the effects on soil productivity, vegetation growth, and wildlife habitat, but little research has focused on the scientific rationale for classifying the post-fire environment. We developed an empirically-grounded soil post-fire index (PFI) based on available...

Soil heating in chaparral fires: effects on soil properties, plant nutrients, erosion, and runoff

Treesearch

Leonard F. DeBano; Raymond M. Rice; Conrad C. Eugene

1979-01-01

This state-of-the-art report summarizes what is known about the effects of heat on soil during chaparral fires. It reviews the literature on the effects of such fires on soil properties, availabilty and loss of plant nutrients, soil wettability, erosion, and surface runoff. And it reports new data collected during recent prescribed burns and a wildfire in southern...

High severity experimental burns in Siberian larch forests increase permafrost thaw and larch tree regeneration

NASA Astrophysics Data System (ADS)

Alexander, H. D.; Davydov, S.; Zimov, N.; Mack, M. C.

2013-12-01

Global change models predict increased fire activity in boreal forests as climate warms and dries. We hypothesized that fire-driven decreases in soil organic layer (SOL) depth will (1) increase permafrost thaw by reducing the insulating capacity of the SOL and (2) improve seedbed conditions for tree regeneration. Over time, these changes will lead to altered patterns of above- and belowground carbon (C) accumulation. To test these hypotheses, we conducted plot-level experimental burns in July 2012 in a low-density, mature larch stand near the Northeast Science Station in Cherskii, Siberia. Dried fuels of naturally occurring vegetation were added to plots to achieve four burn severity treatments based on residual SOL depths: control, low (> 8 cm), moderate (5-8 cm), and high severity (2-5 cm). Pre-fire and during two growing seasons post-fire, we measured thaw depth, soil moisture, and soil temperature to determine severity effects on permafrost thaw. We also sowed larch seeds in fall 2012 and quantified germination rates the following growing season. By 1 wk post-fire, thaw depth was 15-25 cm deeper in plots burned at high severity (55 cm) compared to other treatments (30-40 cm). These differences in thaw depth with burn severity were maintained during the subsequent growing season and were associated with increased soil temperature and moisture. Larch regeneration was 10x higher on severely burned plots than those unburned. Our findings highlight the potential for increased fire severity to degrade permafrost and alter successional dynamics and patterns of C accumulation.

Long-term experiments to better understand soil-human interactions

NASA Astrophysics Data System (ADS)

Bormann, B. T.; Homann, P. S.

2011-12-01

Interactions between soils and people may be transforming global conditions, but the interactions are poorly understood. Changes in soils have proven difficult to quantify, especially in complex ecosystems manifesting large spatiotemporal variability. Long-term ecosystem experiments that evaluate soil change and demonstrate alternative choices are important to understanding changes, discovering new controls and drivers, and influencing decisions. Inspired by agriculture studies, like Rothamsted, the US Forest Service established in 1990 a network of operational-scale experiments across the Pacific Northwest to evaluate long-term effects of different forest management and disturbance regimes. With a strong experimental design, these experiments are now helping to better understand the long-term effects of managing tree harvesting (clearcutting and thinning), woody debris, and tree and understory species composition, and-serendipitously-the effects of fire. Initial results from the Southern Oregon experimental site indicate surprisingly rapid soil changes in some regimes but not others. We've also learned that rapid change presents challenges to repeat sampling. We present our sample-archive and comparable-layer approaches that seek to accommodate changes in surface elevation, aggregation and disaggregation, and mineral-soil exports. Thinning mature forest stands (80-100 yrs old) did not significantly change soil C in 11-yrs. A small upper-layer C increase was observed after thinning, but it was similar to the control. Significant increases in upper-layer soil N were observed with most treatments, but all increases were similar to the control. Leaving woody debris had little effect. The most remarkable change occurred when mature stands were clearcut and Douglas-firs were planted and tended. Associated with rapid growth of Douglas-fir, an average of 8 Mg C ha-1 was lost from weathered soil 4-18 cm deep. This contrasts with clearcuts where early-seral hardwoods and knobcone pines were established, that trended positively with 2 Mg C ha-1. Soil changes resulting from wild and prescribed fire were substantial. About 50% of the soil C (3-21 Mg ha-1) and 36% of soil N (41-650 kg ha-1) were lost from the upper profile (0-6.2 cm) compared to pre-fire conditions. Intense wildfire that killed most forest trees had about double the losses of C and N than forests burned at lower temperature with fewer trees killed. Average wildfire C losses were more than twice prescribed-fire losses. A long-term perspective is needed to compare episodic influences on soils, like harvesting and wildfire, to day-in, day-out effects of different species mixtures. Especially important is the effect of shrubs, that can rapidly achieve full leaf area but that lack the woody stem structure to store captured C as well as conifers. In theory, therefore, extending shrub cover will increase soil C. The annual profile soil C loss in Douglas-fir (-0.8 Mg ha-1yr-1), if continued beyond 11 yrs, would be similar to the effects of a fire-return interval of less than a third of the historical interval of about 100 years. National and regional soil-C monitoring would benefit from being grounded in existing experimental studies to help integrate large-scale changes with an unfolding understanding of processes in ways useful to decisionmakers.

Fire-severity effects on plant-fungal interactions after a novel tundra wildfire disturbance: implications for arctic shrub and tree migration.

PubMed

Hewitt, Rebecca E; Hollingsworth, Teresa N; Stuart Chapin Iii, F; Lee Taylor, D

2016-05-11

Vegetation change in high latitude tundra ecosystems is expected to accelerate due to increased wildfire activity. High-severity fires increase the availability of mineral soil seedbeds, which facilitates recruitment, yet fire also alters soil microbial composition, which could significantly impact seedling establishment. We investigated the effects of fire severity on soil biota and associated effects on plant performance for two plant species predicted to expand into Arctic tundra. We inoculated seedlings in a growth chamber experiment with soils collected from the largest tundra fire recorded in the Arctic and used molecular tools to characterize root-associated fungal communities. Seedling biomass was significantly related to the composition of fungal inoculum. Biomass decreased as fire severity increased and the proportion of pathogenic fungi increased. Our results suggest that effects of fire severity on soil biota reduces seedling performance and thus we hypothesize that in certain ecological contexts fire-severity effects on plant-fungal interactions may dampen the expected increases in tree and shrub establishment after tundra fire.

A review of fire effects on vegetation and soils in the Great Basin region: response and ecological site characteristics

USGS Publications Warehouse

Miller, Richard F.; Chambers, Jeanne C.; Pyke, David A.; Pierson, Fred B.; Williams, C. Jason

2013-01-01

This review synthesizes the state of knowledge on fire effects on vegetation and soils in semi-arid ecosystems in the Great Basin Region, including the central and northern Great Basin and Range, Columbia River Basin, and the Snake River Plain. We summarize available literature related to: (1) the effects of environmental gradients, ecological site, and vegetation characteristics on resilience to disturbance and resistance to invasive species; (2) the effects of fire on individual plant species and communities, biological soil crusts, seed banks, soil nutrients, and hydrology; and (3) the role of fire severity, fire versus fire surrogate treatments, and post-fire grazing in determining ecosystem response. From this, we identify knowledge gaps and present a framework for predicting plant successional trajectories following wild and prescribed fires and fire surrogate treatments. Possibly the three most important ecological site characteristics that influence a site’s resilience (ability of the ecological site to recover from disturbance) and resistance to invasive species are soil temperature/moisture regimes and the composition and structure of vegetation on the ecological site just prior to the disturbance event.

Moss and soil contributions to the annual net carbon flux of a maturing boreal forest

USGS Publications Warehouse

Harden, J.W.; O'Neill, K. P.; Trumbore, S.E.; Veldhuis, H.; Stocks, B.J.

1997-01-01

We used input and decomposition data from 14C studies of soils to determine rates of vertical accumulation of moss combined with carbon storage inventories on a sequence of burns to model how carbon accumulates in soils and moss after a stand-killing fire. We used soil drainage - moss associations and soil drainage maps of the old black spruce (OBS) site at the BOREAS northern study area (NSA) to areally weight the contributions of each moderately well drained, feathermoss areas; poorly drained sphagnum - feathermoss areas; and very poorly drained brown moss areas to the carbon storage and flux at the OBS NSA site. On this very old (117 years) complex of black spruce, sphagnum bog veneer, and fen systems we conclude that these systems are likely sequestering 0.01-0.03 kg C m-2 yr-' at OBS-NSA today. Soil drainage in boreal forests near Thompson, Manitoba, controls carbon storage and flux by controlling moss input and decomposition rates and by controlling through fire the amount and quality of carbon left after burning. On poorly drained soils rich in sphagnum moss, net accumulation and long-term storage of carbon is higher than on better drained soils colonized by feathermosses. The carbon flux of these contrasting ecosystems is best characterized by soil drainage class and stand age, where stands recently burned are net sources of CO2, and maturing stands become increasingly stronger sinks of atmospheric CO2. This approach to measuring carbon storage and flux presents a method of scaling to larger areas using soil drainage, moss cover, and stand age information.

Quantifying Fire Impact on Alaskan Tundra from Satellite Observations and Field Measurements

NASA Astrophysics Data System (ADS)

Loboda, T. V.; Chen, D.; He, J.; Jenkins, L. K.

2017-12-01

Wildfire is a major disturbance agent in Alaskan tundra. The frequency and extent of fire events obtained from paleo, management, and satellite records may yet underestimate the scope of tundra fire impact. Field measurements, collected within the NASA's ABoVE campaign, revealed unexpectedly shallow organic soils ( 15 cm) across all sampled sites of the Noatak valley with no significant difference between recently burned and unburned sites. In typical small and medium-sized tundra burns vegetation recovers rapidly and scars are not discernable in 30 m optical satellite imagery by the end of the first post-fire season. However, field observations indicate that vegetation and subsurface characteristics within fire scars of different ages vary across the landscape. In this study we develop linkages between fire-induced changes to tundra and satellite-based observations from optical, thermal, and microwave imagers to enable extrapolation of in-situ observations to cover the full extent of Alaskan tundra. Our results show that recent ( 30 years) fire history can be reconstructed from optical observations (R2 0.65, p<0.001) within a specific narrow temporal window or thermal signatures (R2 0.54, p < 0.001), in both cases controlled for slope and southern exposure. Using microwave SAR imagery fire history can be determined for 4 years post fire primarily due to increased soil moisture at burned sites. Field measurements suggest that the relatively quick SAR signal dissipation results from more even distribution of surface moisture through the soil column with increases in Active Layer Thickness (ALT). Similar to previous long-term field studies we find an increase in shrub fraction and shrub height within burns over time at the landscape scale; however, the strength and significance of the relationship between shrub fraction and time since fire is governed by burn severity with more severe burns predictably (p < 0.01) resulting in higher post-fire shrub cover. Although reasonably well-correlated to each other when adjusted for topography (R2 0.35, p < 0.001), neither ALT nor soil temperature can be directly linked to optical or thermal brightness observations with acceptable statistical significance, necessitating a more complex modeling environment for wall-to-wall mapping of subsurface parameters.

Modeling long-term changes in tundra carbon balance following wildfire, climate change, and potential nutrient addition.

PubMed

Jiang, Yueyang; Rastetter, Edward B; Shaver, Gaius R; Rocha, Adrian V; Zhuang, Qianlai; Kwiatkowski, Bonnie L

2017-01-01

To investigate the underlying mechanisms that control long-term recovery of tundra carbon (C) and nutrients after fire, we employed the Multiple Element Limitation (MEL) model to simulate 200-yr post-fire changes in the biogeochemistry of three sites along a burn severity gradient in response to increases in air temperature, CO 2 concentration, nitrogen (N) deposition, and phosphorus (P) weathering rates. The simulations were conducted for severely burned, moderately burned, and unburned arctic tundra. Our simulations indicated that recovery of C balance after fire was mainly determined by the internal redistribution of nutrients among ecosystem components (controlled by air temperature), rather than the supply of nutrients from external sources (e.g., nitrogen deposition and fixation, phosphorus weathering). Increases in air temperature and atmospheric CO 2 concentration resulted in (1) a net transfer of nutrient from soil organic matter to vegetation and (2) higher C : nutrient ratios in vegetation and soil organic matter. These changes led to gains in vegetation biomass C but net losses in soil organic C stocks. Under a warming climate, nutrients lost in wildfire were difficult to recover because the warming-induced acceleration in nutrient cycles caused further net nutrient loss from the system through leaching. In both burned and unburned tundra, the warming-caused acceleration in nutrient cycles and increases in ecosystem C stocks were eventually constrained by increases in soil C : nutrient ratios, which increased microbial retention of plant-available nutrients in the soil. Accelerated nutrient turnover, loss of C, and increasing soil temperatures will likely result in vegetation changes, which further regulate the long-term biogeochemical succession. Our analysis should help in the assessment of tundra C budgets and of the recovery of biogeochemical function following fire, which is in turn necessary for the maintenance of wildlife habitat and tundra vegetation. © 2016 by the Ecological Society of America.

Do agricultural terraces and forest fires recurrence in Mediterranean afforested micro-catchments alter soil quality and soil nutrient content?

NASA Astrophysics Data System (ADS)

E Lucas-Borja, Manuel; Calsamiglia, Aleix; Fortesa, Josep; García-Comendador, Julián; Gago, Jorge; Estrany, Joan

2017-04-01

Bioclimatic characteristics and intense human pressure promote Mediterranean ecosystems to be fire-prone. Afforestation processes resulting from the progressive land abandonment during the last decades led to greater biomass availability increasing the risk of large forest fires. Likewise, the abandonment and lack of maintenance in the terraced lands constitute a risk of land degradation in terms of soil quantity and quality. Despite the effects of fire and the abandonment of terraced lands on soil loss and physico-chemical properties are identified, it is not clearly understood how wildfires and abandonment of terraces affect soil quality and nutrients content. Microbiological soil parameters and soil enzymes activities are biomarkers of the soil microbial communitýs functional ability, which potentially enables them as indicators of change, disturbance or stress within the soil community. The objective of this study was to investigate the effects of terracing (abandoned and non-abandoned) on the soil enzyme activities, microbiological soil parameters and soil nutrients dynamics in three Mediterranean afforested micro-catchments (i.e., < 2 ha) under different forest fire recurrence in the last 20 years; i.e., unburned areas, burned once and burned twice. The combination of the presence of terraces and the recurrence of forest fire, thirty-six plots of 25 m2 were sampled along the these three micro-catchments collecting four replicas at the corners of each plot. The results elucidated how non-terraced and unburned plots presented the highest values of soil respiration rate and extracellular soil enzymes. Differences between experimental plots with different forest fire recurrence or comparing terraced and unburned plots with burned plots were weaker in relation to biochemical and microbiological parameters. Soil nutrient content showed an opposite trend with higher values in terraced plots, although differences were weaker. We conclude that terraced landscapes present poorer soil quality parameters due to land abandonment and the lack of terraced management. In addition, forest fire recurrence exacerbates soil degradation processes due to the direct effects on vegetation and soil properties.

Fire regime, not time-since-fire, affects soil fungal community diversity and composition in temperate grasslands.

PubMed

Egidi, Eleonora; McMullan-Fisher, Sapphire; Morgan, John W; May, Tom; Zeeman, Ben; Franks, Ashley E

2016-09-01

Frequent burning is commonly undertaken to maintain diversity in temperate grasslands of southern Australia. How burning affects below-ground fungal community diversity remains unknown. We show, using a fungal rDNA metabarcoding approach (Illumina MiSeq), that the fungal community composition was influenced by fire regime (frequency) but not time-since-fire. Fungal community composition was resilient to direct fire effects, most likely because grassland fires transfer little heat to the soil. Differences in the fungal community composition due to fire regime was likely due to associated changes that occur in vegetation with recurrent fire, via the break up of obligate symbiotic relationships. However, fire history only partially explains the observed dissimilarity in composition among the soil samples, suggesting a distinctiveness in composition in each grassland site. The importance of considering changes in soil microbe communities when managing vegetation with fire is highlighted. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Effects of Phos-Chek® on soil nutrient availability

USDA-ARS?s Scientific Manuscript database

Wildfire frequencies and intensities have been steadily increasing on western US landscapes. Phos-chek® is an aerially-applied fire retardant used to contain and control wildfires. Composed of ammonium and phosphate salts, Phos-chek® has the potential to increase soil nutrient availability of N and ...

Comparison of six fire severity classification methods using Montana and Washington wildland fires

Treesearch

Pamela G. Sikkink

2015-01-01

Fire severity classifications are used in the post-fire environment to describe fire effects, such as soil alteration or fuel consumption, on the forest floor. Most of the developed classifications are limited because they address very specific fire effects or post-burn characteristics in the burned environment. However, because fire effects vary so much among soil,...

Evaluation of the rusle and disturbed wepp erosion models for predicting soil loss in the first year after wildfire in NW Spain.

PubMed

Fernández, Cristina; Vega, José A

2018-05-04

Severe fire greatly increases soil erosion rates and overland-flow in forest land. Soil erosion prediction models are essential for estimating fire impacts and planning post-fire emergency responses. We evaluated the performance of a) the Revised Universal Soil Loss Equation (RUSLE), modified by inclusion of an alternative equation for the soil erodibility factor, and b) the Disturbed WEPP model, by comparing the soil loss predicted by the models and the soil loss measured in the first year after wildfire in 44 experimental field plots in NW Spain. The Disturbed WEPP has not previously been validated with field data for use in NW Spain; validation studies are also very scarce in other areas. We found that both models underestimated the erosion rates. The accuracy of the RUSLE model was low, even after inclusion of a modified soil erodibility factor accounting for high contents of soil organic matter. We conclude that neither model is suitable for predicting soil erosion in the first year after fire in NW Spain and suggest that soil burn severity should be given greater weighting in post-fire soil erosion modelling. Copyright © 2018 Elsevier Inc. All rights reserved.

Carbon stocks and fluxes in fire disturbed landscapes of Colorado, U.S.A.

NASA Astrophysics Data System (ADS)

Barnes, R. T.; Wolf, K.; Whittinghill, K. A.; Gilbertson, A.; Buma, B.

2016-12-01

In terrestrial ecosystems, ecological disturbances can strongly regulate material and energy flows. This often results from the reduction in biomass and associated ecological relationships and physiological processes. Researchers have noted an increase in the size and severity of disturbances, such as wildfire, in recent decades. While there is significant research examining post-disturbance carbon stocks and recovery, there is less known about the fate and quality of post-disturbance carbon pools. In an effort to understand the recovery and resilience of forest carbon stocks to severe wildfire we examined the carbon and black carbon (pyrogenic) stocks (e.g. above ground biomass, coarse woody debris, charcoal, soils) and export fluxes (stream export, soil leachate, soil respiration) within the burn scars and nearby reference sites of five 2002 Colorado fires. The fires encompass large precipitation and ecosystem gradients (relatively dry montane Ponderosa forests to relatively wet subalpine Lodgepole forests), allowing us to control for various state factors in our analyses. With the exception of the Hinman fire (subalpine, Lodgepole dominated), there is little forest regrowth more than a decade later, with only a few saplings found in burned plots; instead forbes and grasses dominate. Fire also reduces soil C stocks (by 16 to 68%) across all sites. In addition, with the shifts in vegetation we hypothesize that there will be corresponding changes in soil organic matter (SOM), altering the residence time of C in soil. Soil incubation experiments reveal that organic matter bioavailability is significantly greater in three of the burned sites, suggesting that the new sources of SOM are more bioavailable. Stable isotopic analyses of SOM and the evolved CO2 from the incubation studies will allow us to test this hypothesis. Fire also affects the amount and nature of dissolved and particulate organic matter (DOM and POM, respectively) leaving the watershed. For example, the dissolved organic matter exported from burned watersheds is less aromatic and has lower C:N than DOM exported from reference watersheds. In addition to measuring these fluxes, we assessed the fate of leached DOM via laboratory bioassays to determine the likelihood of additional CO2 losses to the atmosphere.

Wildfire effects on C stocks in mountain soils

NASA Astrophysics Data System (ADS)

Menéndez-Duarte, R.; Fernández, S.; Santin, C.; Gaspar, L.; Navas, A.

2012-04-01

Wildfire is the main perturbation agent in mountain soils of the Cantabrian Range (NW of Spain). Fire affects soil organic carbon (SOC) quality and quantity, both directly (e.g. combustion of organic matter and pyrogenic carbon production) and indirectly (e.g. increase of soil erosion and change of the vegetation cover). After fire, the organic fraction of the soil is expected to be enriched with charred compounds (black carbon, biochar or pyrogenic carbon-PyC). PyC mainly contributes to the recalcitrant C pool and therefore to the medium- and long-term C sequestration in soils. Moreover, recurrent fires in these Atlantic mountain ecosystems cause the conversion of the vegetation cover from forest to heathland, altering C transfer from biomass to soil. On the other hand, in this steep terrain, fire enhances soil erosion by creeping and therefore soil loss and the consequent loss of SOC. Thus, a basic but fundamental question arises: which is the net variation of SOC stocks in these mountain soils due to wildfires? To answer this, soils were sampled in a typical quartzite steep mountain in the Somiedo Natural Park (NW of Spain): i) a transect in the South hillside, prone to fires and with an intense fire history, where the vegetation cover is mostly heather and gorse; and ii) a transect in the North hillside, less affected by fire and with a well preserved vegetation cover (beech and oak forest). Samples of the surface soil (0-5 cm) and the whole soil profile were taken and, bulk density and SOC content were determined. On average fire-affected soils in the South transect have a lower soil depth (12.0 cm) and lower bulk density (0.5 g/cm3) than the North transect soils (17.6 cm depth and 1.0 g/cm3 bulk density) but they have also SOC concentrations six times higher than their unburned counterparts (147.5 and 22.8 mg C/g soil, respectively). When considering SOC stocks, differences are not as pronounced but, even so, fire affected soils content twice as much SOC (7.4 kg /m2) than the unburned soils (3.2 kg SOC/m2). Characterisation of SOC is being carried out by thermogravimetry-differential scanning calorimetry to identify the qualitative differences of SOC in burned and unburned soils and to quantify the proportion of PyC, which may play a main role in the potential of these mountain soils as long-term C reservoirs.

Species-abundance distribution patterns of soil fungi: contribution to the ecological understanding of their response to experimental fire in Mediterranean maquis (southern Italy).

PubMed

Persiani, Anna Maria; Maggi, Oriana

2013-01-01

Experimental fires, of both low and high intensity, were lit during summer 2000 and the following 2 y in the Castel Volturno Nature Reserve, southern Italy. Soil samples were collected Jul 2000-Jul 2002 to analyze the soil fungal community dynamics. Species abundance distribution patterns (geometric, logarithmic, log normal, broken-stick) were compared. We plotted datasets with information both on species richness and abundance for total, xerotolerant and heat-stimulated soil microfungi. The xerotolerant fungi conformed to a broken-stick model for both the low- and high intensity fires at 7 and 84 d after the fire; their distribution subsequently followed logarithmic models in the 2 y following the fire. The distribution of the heat-stimulated fungi changed from broken-stick to logarithmic models and eventually to a log-normal model during the post-fire recovery. Xerotolerant and, to a far greater extent, heat-stimulated soil fungi acquire an important functional role following soil water stress and/or fire disturbance; these disturbances let them occupy unsaturated habitats and become increasingly abundant over time.

Carbon dioxide, methane and nitrous oxide fluxes from a fire chronosequence in subarctic boreal forests of Canada.

PubMed

Köster, Egle; Köster, Kajar; Berninger, Frank; Aaltonen, Heidi; Zhou, Xuan; Pumpanen, Jukka

2017-12-01

Forest fires are one of the most important natural disturbances in boreal forests, and their occurrence and severity are expected to increase as a result of climate warming. A combination of factors induced by fire leads to a thawing of the near-surface permafrost layer in subarctic boreal forest. Earlier studies reported that an increase in the active layer thickness results in higher carbon dioxide (CO 2 ) and methane (CH 4 ) emissions. We studied changes in CO 2 , CH 4 and nitrous oxide (N 2 O) fluxes in this study, and the significance of several environmental factors that influence the greenhouse gas (GHG) fluxes at three forest sites that last had fires in 2012, 1990 and 1969, and we compared these to a control area that had no fire for at least 100years. The soils in our study acted as sources of CO 2 and N 2 O and sinks for CH 4 . The elapsed time since the last forest fire was the only factor that significantly influenced all studied GHG fluxes. Soil temperature affected the uptake of CH 4 , and the N 2 O fluxes were significantly influenced by nitrogen and carbon content of the soil, and by the active layer depth. Results of our study confirm that the impacts of a forest fire on GHGs last for a rather long period of time in boreal forests, and are influenced by the fire induced changes in the ecosystem. Copyright © 2017 Elsevier B.V. All rights reserved.

Fire vegetative ash and erosion in the Mediterranean areas. State of the art and future perspectives

NASA Astrophysics Data System (ADS)

Pereira, Paulo; Cerdà, Artemi

2013-04-01

Fire is a global phenomenon with important ecological impacts. Among all ecosystems, the Mediterranean is frequently visited by severe wildfires with serious impacts on soil properties and increase soil vulnerability to erosion due vegetation removal. After the fire the ash distributed in soil surface can mitigate soil exposition to erosion and rain splash (Cerda and Doerr, 2008), however, this depends on the fire severity that have implications on the type of ash produced (Pereira et al., 2010). High fire severities produced thinner ash that it is easily transported by wind, contrary to low severity wildfires where combustion is not so intense and the mass loss is less, providing a better soil protection in the immediate period after the fire. Soil protection after the fire highly depends on fire severity (Pereira et al. 2013a; Pereira et al. 2013b). Ash it is a highly mobile material, thus this protection can change in space and time, providing a better cover in some areas and worst in others. In the period immediate after the fire, ash can change soil hydrological properties, increasing water retention and reducing sediment transport in relation to bare soil areas (Cerda and Doerr, 2008), but also clog soil pores, seal the soil and increase erosion (Onda et al., 2008). In fact results are controversial and the impacts of vegetative ash in soil erosion may rely on the proprieties of ash produced, that can be extremely variable, even in small distances (Pereira and Úbeda, 2010), due the different conditions of combustions. Ash produced at low severity temperatures can be highly hydrophilic (Bodi et al., 2011) and induce soil hydrophobicity (Bodi et al., 2012). Other mechanisms as the direct impact of fire in soil, can induce soil water repellency, and do not have any interference of vegetative ash. This fire can induce direct (e.g temperature) and indirect (e.g. ash properties) on soil wettability, with obvious implications on spatio-temporal pattern of soil erosion. At this point we are dealing with a complex interaction since interactions, since low severity fires due ash, and high severity fires, due temperature induce soil hydrophobicity. After the fire, other ash properties may interact with soil erosion, as particulate size, and chemical composition, that can induce soil particulates flocculation or dispersion. Ash chemistry is strongly related with fire severity (Pereira et al., 2012). Further studies may be directed in the complex interaction between ash physico-chemical properties interaction with the degree of fire impacts on soil. These and other ideas will be discussed during the session. Acknowledgements, The authors appreciated the support of the project "Litfire", Fire effects in Lithuanian soils and ecosystems (MIP-048/2011) funded by the Lithuanian Research Council and FUEGORED (Spanish Network of Forest Fire Effects on Soils http://grupo.us.es/fuegored/). References Bodi, M., Doerr, S., Cerdà, A., Mataix-Solera, J. (2012) Hydrological effects of a layer of vegetation ash on underlying wettable and water repellent soil. Geoderma 191: 14-13. Bodi, M., Mataix-Solera, J., Doerr, S., Cerdà, A. (2011) The wettability of ash from burned vegetation and its relationship to Mediterranean plant species type, burn severity and total organic matter content. Geoderma, 160, 599-607. Cerdà, A., Doerr, S.H. (2008). The effect of ash and needle cover on surface runoff and erosion in the immediate post-fire period. Catena, 74, 256-263. Onda Y, Dietrich WE, Booker F. 2008. Evolution of overland flow after a severe forest fire, Point Reyes, California. Catena. 72, 13-20. Pereira, P., Bodi. M., Úbeda, X., Cerdà, A., Mataix-Solera, J., Balfour, V, Woods, S. (2010) Las cenizas y el ecosistema suelo, In: Cerdà, A. Jordan, A. (eds) Actualización en métodos y técnicas para el estudio de los suelos afectados por incendios forestales, 345-398. Càtedra de Divulgació de la Ciència. Universitat de Valencia. ISBN: 978-84-370-7887-8. Deposito Legal: V-3541-2010. Pereira, P., Cerdà, A., Úbeda, X., Mataix-Solera, J. Arcenegui, V., Zavala, L. (2013a) Modelling the impacts of wildfire on ash thickness in a short-term period, Land Degradation and Development, (In Press), DOI: 10.1002/ldr.2195 Pereira, P., Cerdà, A., Úbeda, X., Mataix-Solera, J., Jordan, A. Burguet, M. (2013b) Effects of fire on ash thickness in a Lithuanian grassland and short-term spatio-temporal changes, Solid Earth Discussions,4, 1545-1584. Pereira, P., Úbeda, X. (2010) Spatial variation of heavy metals released from ashes after a wildfire, Journal of Environmental Engineering and Landscape Management 18(1), 13-22. Pereira, P., Úbeda, X., Martin, D. (2012) Fire severity effects on ash chemical composition and water-extractable elements, Geoderma, 191, 105-114.

Linking hydraulic properties of fire-affected soils to infiltration and water repellency

USGS Publications Warehouse

Moody, John A.; David Kinner,; Xavier Úbeda,

2009-01-01

Heat from wildfires can produce a two-layer system composed of extremely dry soil covered by a layer of ash, which when subjected to rainfall, may produce extreme floods. To understand the soil physics controlling runoff for these initial conditions, we used a small, portable disk infiltrometer to measure two hydraulic properties: (1) near-saturated hydraulic conductivity, Kf and (2) sorptivity, S(θi), as a function of initial soil moisture content, θi, ranging from extremely dry conditions (θi < 0.02 cm3 cm−3) to near saturation. In the field and in the laboratory replicate measurements were made of ash, reference soils, soils unaffected by fire, and fire-affected soils. Each has a different degrees of water repellency that influences Kf and S(θi).Values of Kf ranged from 4.5 × 10−3 to 53 × 10−3 cm s−1 for ash; from 0.93 × 10−3 to 130 × 10−3 cm s−1 for reference soils; and from 0.86 × 10−3 to 3.0 × 10−3 cm s−1, for soil unaffected by fire, which had the lowest values of Kf. Measurements indicated that S(θi) could be represented by an empirical non-linear function of θi with a sorptivity maximum of 0.18–0.20 cm s−0.5, between 0.03 and 0.08 cm3 cm−3. This functional form differs from the monotonically decreasing non-linear functions often used to represent S(θi) for rainfall–runoff modeling. The sorptivity maximum may represent the combined effects of gravity, capillarity, and adsorption in a transitional domain corresponding to extremely dry soil, and moreover, it may explain the observed non-linear behavior, and the critical soil-moisture threshold of water repellent soils. Laboratory measurements of Kf and S(θi) are the first for ash and fire-affected soil, but additional measurements are needed of these hydraulic properties for in situ fire-affected soils. They provide insight into water repellency behavior and infiltration under extremely dry conditions. Most importantly, they indicate how existing rainfall–runoff models can be modified to accommodate a possible two-layer system in extremely dry conditions. These modified models can be used to predict floods from burned watersheds under these initial conditions.

Infiltration and runoff generation processes in fire-affected soils

USGS Publications Warehouse

Moody, John A.; Ebel, Brian A.

2014-01-01

Post-wildfire runoff was investigated by combining field measurements and modelling of infiltration into fire-affected soils to predict time-to-start of runoff and peak runoff rate at the plot scale (1 m2). Time series of soil-water content, rainfall and runoff were measured on a hillslope burned by the 2010 Fourmile Canyon Fire west of Boulder, Colorado during cyclonic and convective rainstorms in the spring and summer of 2011. Some of the field measurements and measured soil physical properties were used to calibrate a one-dimensional post-wildfire numerical model, which was then used as a ‘virtual instrument’ to provide estimates of the saturated hydraulic conductivity and high-resolution (1 mm) estimates of the soil-water profile and water fluxes within the unsaturated zone.Field and model estimates of the wetting-front depth indicated that post-wildfire infiltration was on average confined to shallow depths less than 30 mm. Model estimates of the effective saturated hydraulic conductivity, Ks, near the soil surface ranged from 0.1 to 5.2 mm h−1. Because of the relatively small values of Ks, the time-to-start of runoff (measured from the start of rainfall),  tp, was found to depend only on the initial soil-water saturation deficit (predicted by the model) and a measured characteristic of the rainfall profile (referred to as the average rainfall acceleration, equal to the initial rate of change in rainfall intensity). An analytical model was developed from the combined results and explained 92–97% of the variance of  tp, and the numerical infiltration model explained 74–91% of the variance of the peak runoff rates. These results are from one burned site, but they strongly suggest that  tp in fire-affected soils (which often have low values of Ks) is probably controlled more by the storm profile and the initial soil-water saturation deficit than by soil hydraulic properties.

Bringing soil science to society after catastrophic events such as big forest fires. Some examples of field approaches in Spanish Mediterranean areas

NASA Astrophysics Data System (ADS)

Mataix-Solera, Jorge; Arcenegui, Vicky; Cerdà, Artemi; García-Orenes, Fuensanta; Moltó, Jorge; Chrenkovà, Katerina; Torres, Pilar; Lozano, Elena; Jimenez-Pinilla, Patricia; Jara-Navarro, Ana B.

2015-04-01

Forest fires must be considered a natural factor in Mediterranean ecosystems, but the changes in land use in the last six decades have altered its natural regime making them an ongoing environmental problem. Some big forest fires (> 500 has) also have a great socio-economical impact on human population. Our research team has experience of 20 years studying the effects of forest fires on soil properties, their recovery after fire and the impact of some post-fire management treatments. In this work we want to show our experience of how to transfer part of our knowledge to society after two catastrophic events of forest fires in the Alicante Province (E Spain). Two big forest fires: one in "Sierra de Mariola (Alcoi)" and other in "Montgó Natural Park (Javea-Denia)" occurred in in July 2012 and September 2014 respectivelly, and as consequence a great impact was produced on the populations of nearby affected villages. Immediatelly, some groups were formed through social networks with the aim of trying to help recover the affected areas as soon as possible. Usually, society calls for early reforestation and this preassure on forest managers and politicians can produce a response with a greater impact on fire-affected area than the actual fire. The soil is a fragile ecosystem after forest fire, and the situation after fire can vary greatly depending on many factors such as fire severity, previous history of fire in the area, soil type, topography, etc. An evaluation of the site to make the best decision for recovery of the area, protecting the soil and avoiding degradation of the ecosystem is necessary. In these 2 cases we organized some field activities and conferences to give society knowledge of how soil is affected by forest fires, and what would be the best post-fire management depending on how healthy the soil is and the vegetation resilience after fire and our expectations for a natural recovery. The application of different types of mulch in vulnerable areas, the participation of people on the days when we started field research with installation of plots and soil samplings, field trips with volunteers of some NGO's, etc., are some of examples of what we will show in this presentation of how to bring soil science to society. Acknowledgements: to the "Ministerio de Economía and Competitividad" of Spanish Government for finance the POSTFIRE project (CGL2013- 47862-C2-1-R), FUEGORED, Spanish Soil Science Society, Alcoi and Javea councils, Botánica Mediterrànea, ACIF Alcoi, ACIF Marina Alta, Xàbia Viva, Montgó Viu, and Sierra de Mariola and Montgó Natural Parks for their collaboration.

Effects of fire disturbance on soil respiration in the non-growing season in a Larix gmelinii forest in the Daxing'an Mountains, China.

PubMed

Hu, Tongxin; Sun, Long; Hu, Haiqing; Guo, Futao

2017-01-01

In boreal forests, fire is an important part of the ecosystem that greatly influences soil respiration, which in turn affects the carbon balance. Wildfire can have a significant effect on soil respiration and it depends on the fire severity and environmental factors (soil temperature and snow water equivalent) after fire disturbance. In this study, we quantified post-fire soil respiration during the non-growing season (from November to April) in a Larix gmelinii forest in Daxing'an Mountains of China. Soil respiration was measured in the snow-covered and snow-free conditions with varying degrees of natural burn severity forests. We found that soil respiration decreases as burn severity increases. The estimated annual C efflux also decreased with increased burn severity. Soil respiration during the non-growing season approximately accounted for 4%-5% of the annual C efflux in all site types. Soil temperature (at 5 cm depth) was the predominant determinant of non-growing season soil respiration change in this area. Soil temperature and snow water equivalent could explain 73%-79% of the soil respiration variability in winter snow-covering period (November to March). Mean spring freeze-thaw cycle (FTC) period (April) soil respiration contributed 63% of the non-growing season C efflux. Our finding is key for understanding and predicting the potential change in the response of boreal forest ecosystems to fire disturbance under future climate change.

Effects of fire disturbance on soil respiration in the non-growing season in a Larix gmelinii forest in the Daxing'an Mountains, China

PubMed Central

Hu, Tongxin; Guo, Futao

2017-01-01

In boreal forests, fire is an important part of the ecosystem that greatly influences soil respiration, which in turn affects the carbon balance. Wildfire can have a significant effect on soil respiration and it depends on the fire severity and environmental factors (soil temperature and snow water equivalent) after fire disturbance. In this study, we quantified post-fire soil respiration during the non-growing season (from November to April) in a Larix gmelinii forest in Daxing'an Mountains of China. Soil respiration was measured in the snow-covered and snow-free conditions with varying degrees of natural burn severity forests. We found that soil respiration decreases as burn severity increases. The estimated annual C efflux also decreased with increased burn severity. Soil respiration during the non-growing season approximately accounted for 4%–5% of the annual C efflux in all site types. Soil temperature (at 5 cm depth) was the predominant determinant of non-growing season soil respiration change in this area. Soil temperature and snow water equivalent could explain 73%–79% of the soil respiration variability in winter snow-covering period (November to March). Mean spring freeze–thaw cycle (FTC) period (April) soil respiration contributed 63% of the non-growing season C efflux. Our finding is key for understanding and predicting the potential change in the response of boreal forest ecosystems to fire disturbance under future climate change. PMID:28665958

Effects of slash, machine passes, and soil moisture on penetration resistance in a cut-to-length harvesting

Treesearch

Han-Sup Han; Debbie Page-Dumroese; Sang-Kyun Han; Joanne Tirocke

2006-01-01

Multiple entries into forest stands are often needed for fire hazard reduction and ecosystem restoration treatments in the Inland-Northwest U.S.A. region. However, soil compaction occurring from mechanized harvesting operations often remains for many years and may contribute to a decline in long-term site productivity. A controlled experiment on a silt loam soil was...

The Interacting controls of pyrolysis temperature and plant taxa on pyrogenic organic matter stability and decomposition in a Northern Michigan forest soil

NASA Astrophysics Data System (ADS)

Gibson, C. D.; Filley, T. R.; Bird, J. A.; Hatton, P. J.; Stark, R. E.; Nadelhoffer, K. J.

2017-12-01

Pyrogenic organic matter (PyOM) produced during forest fires is considered a large sink of stable soil organic matter (SOM) in boreal-temperate forest ecotones, where fire frequency and intensity is growing with changing climate. Understanding how changes in fire regime and predicted shifts in plant taxa will interact to affect PyOM dynamics in soil is imperative to assessing the impact of climate change on SOM maintenance. The stability of PyOM in soil may be co-determined by the physiochemical structure imparted on PyOM during pyrolysis and by its initial taxa-dependent wood chemistry and anatomy. To determine PyOM-C turnover rates in soil, we followed the fate of 13C-enriched wood or PyOM (200, 300, 450, or 600°C) derived from red maple (RM) or jack pine (JP) wood in soil from a recently burned forest in northern Michigan, USA. We found that pyrolysis temperature-controlled physiochemical changes influenced, with threshold dynamics, PyOM stability resulting in mean residence times of 2 (PyOM 200°C) to 450 years for both taxa, confirming that most PyOM (<600°C) turns over on the century, not millennial time scale. Water leachable C, carbohydrate and non-lignin phenol content correlated positively with early PyOM-C mineralization for both JP and RM, but the pyrolysis temperature at which this interaction was strongest differed with taxa reflecting the difference in thermal transition in which carbonization begins (300°C for JP and 450°C for RM). In contrast to previous studies, the addition of sucrose suggests that a co-metabolism mechanism of PyOM decomposition is minor in this soil. Our results show that while the first order control on PyOM stability in this soil is pyrolysis temperature, wood taxa did affect PyOM C MRT, in part due to differences in the amount of water soluble C released by PyOM during the initial decomposition dynamics in soil.

Spatial variability of soils in a seasonally dry tropical forest

NASA Astrophysics Data System (ADS)

Pulla, Sandeep; Riotte, Jean; Suresh, Hebbalalu; Dattaraja, Handanakere; Sukumar, Raman

2016-04-01

Soil structures communities of plants and soil organisms in tropical forests. Understanding the controls of soil spatial variability can therefore potentially inform efforts towards forest restoration. We studied the relationship between soils and lithology, topography, vegetation and fire in a seasonally dry tropical forest in southern India. We extensively sampled soil (available nutrients, Al, pH, and moisture), rocks, relief, woody vegetation, and spatial variation in fire burn frequency in a permanent 50-ha plot. Lower elevation soils tended to be less moist and were depleted in several nutrients and clay. The availability of several nutrients was, in turn, linked to whole-rock chemical composition differences since some lithologies were associated with higher elevations, while the others tended to dominate lower elevations. We suggest that local-scale topography in this region has been shaped by the spatial distribution of lithologies, which differ in their susceptibility to weathering. Nitrogen availability was uncorrelated with the presence of trees belonging to Fabaceae, a family associated with N-fixing species. No effect of burning on soil parameters could be discerned at this scale.

Using synthetic polymers to reduce soil erosion after forest fires in Mediterranean soils

NASA Astrophysics Data System (ADS)

Lado, Marcos; Ben-Hur, Meni; Inbar, Assaf

2010-05-01

Forest fires are a major environmental problem in the Mediterranean region because they result in a loss of vegetation cover, changes in biodiversity, increases in greenhouse gasses emission and a potential increase of runoff and soil erosion. The large increases in runoff and sediment yields after high severity fires have been attributed to several factors, among them: increase in soil water repellency; soil sealing by detached particles and by ash particles, and the loss of a surface cover. The presence of a surface cover increases infiltration, and decreases runoff and erosion by several mechanisms which include: rainfall interception, plant evapotranspiration, preservation of soil structure by increasing soil organic matter, and increasing surface roughness. The loss of vegetation cover as a result of fire leaves the surface of the soil exposed to the direct impact of the raindrops, and therefore the sensitivity of the soil to runoff generation and soil loss increases. In this work, we propose a new method to protect soils against post-fire erosion based on the application of synthetic polymers to the soil. Laboratory rainfall simulations and field runoff plots were used to analyze the suitability of the application of synthetic polymers to reduce soil erosion and stabilize soil structure in Mediterranean soils. The combination of these two processes will potentially favor a faster recovery of the vegetation structure. This method has been successfully applied in arable land, however it has not been tested in burnt forests. The outcome of this study may provide important managerial tools for forest management following fires.

Short term effects of fire on soil respiration in Peruvian Amazon

NASA Astrophysics Data System (ADS)

Suarez, L. F.; Kruijt, B.

2008-05-01

Severe changes are affecting the role of Amazon in the Earth system. One of these possible effects could be the modification of the role of soils in the carbon cycle due to land use and land cover change activities mainly involving the change of forest by crops. In this sense, fire is the main tool used by farmers for land use and also is an important factor for mobilizing C from the soil to the atmosphere, mainly as CO2. This could have an important effect in the global warming. This proposal will evaluate the variation of the soil respiration related to the seasonality and the fire effects on soils in the Amazon of Peru and Brazil. In experimental locations of Peru with different vegetation cover (forest and pasture), we measured soil respiration along with the organic carbon and the microbial biomass of soils during campaigns covering wet and dry seasons. Complementary measurements of soil temperature, water and nutrient content were performed. Also, we reproduced a fire experiment simulating agricultural local activity by the technique of "slash and burn" to evaluate fire effects on soil respiration. Measurements were taken after the soil cooled and at least 3 days after the fire. Additionally, the carbon stocks of the subplots were evaluated. Evaluation of the variations of CO2 fluxes and the capacity of adaptation to fire and water content are discussed through the comparisons of the different locations, type of soils and concentration of available N (nitrate and ammonium) as an indicator of nutrient content.

FIRE STUDIES IN MALLEE (EUCALYPTUS SPP.) COMMUNITIES OF WESTERN NEW SOUTH WALES: SPATIAL AND TEMPORAL FLUXES IN SOIL CHEMISTRY AND SOIL BIOLOGY FOLLOWING PRESCRIBED FIRE.

EPA Science Inventory

The effects of prescribed fires on nutrient pools, soil-organisms, and vegetation patch dynamics were studied in three semi-arid mallee shrublands in western New South Wales. Repeated sampling of surface soil strata (0-2 and 2-4 cm) was undertaken at strategic times (immediately ...

Effects of Grazing and Fire Frequency on Floristic Quality and its Relationship to Indicators of Soil Quality in Tallgrass Prairie

NASA Astrophysics Data System (ADS)

Manning, George C.; Baer, Sara G.; Blair, John M.

2017-12-01

Fire and grazing are widely used to manage grasslands for conservation purposes, but few studies have evaluated the effects of these drivers on the conservation value of plant communities measured by the floristic quality index (FQI). Further, the influence of fire and grazing on soil properties and functions are difficult for land managers and restoration practitioners to assess. The objectives of this study were to: (1) quantify the independent and interactive effects of grazing and fire frequency on floristic quality in native tallgrass prairie to provide potential benchmarks for community assessment, and (2) to explore whether floristic quality can serve as an indicator of soil structure and function for more holistic ecosystem assessments. A factorial combination of fire frequencies (1-2, 4, and 20 years return intervals) and grazing (by bison or ungrazed) treatments were sampled for plant species composition, and for several indicators of soil quality in lowland tallgrass prairie. Floristic quality, diversity, and richness were higher in grazed than ungrazed prairie over all fire frequencies ( P < 0.05). Available inorganic N, microbial biomass N, total N, and soil bulk density were also higher in grazed prairie soil over all fire frequencies ( P < 0.05). Microbial biomass C, total organic C, and total soil N were positively correlated with FQI ( P < 0.05). This study shows that floristic quality and soil N pools are more strongly influenced by grazing than fire and that floristic quality can be an indicator of total soil C and N stocks in never cultivated lowland prairie.

Effects of Grazing and Fire Frequency on Floristic Quality and its Relationship to Indicators of Soil Quality in Tallgrass Prairie.

PubMed

Manning, George C; Baer, Sara G; Blair, John M

2017-12-01

Fire and grazing are widely used to manage grasslands for conservation purposes, but few studies have evaluated the effects of these drivers on the conservation value of plant communities measured by the floristic quality index (FQI). Further, the influence of fire and grazing on soil properties and functions are difficult for land managers and restoration practitioners to assess. The objectives of this study were to: (1) quantify the independent and interactive effects of grazing and fire frequency on floristic quality in native tallgrass prairie to provide potential benchmarks for community assessment, and (2) to explore whether floristic quality can serve as an indicator of soil structure and function for more holistic ecosystem assessments. A factorial combination of fire frequencies (1-2, 4, and 20 years return intervals) and grazing (by bison or ungrazed) treatments were sampled for plant species composition, and for several indicators of soil quality in lowland tallgrass prairie. Floristic quality, diversity, and richness were higher in grazed than ungrazed prairie over all fire frequencies (P < 0.05). Available inorganic N, microbial biomass N, total N, and soil bulk density were also higher in grazed prairie soil over all fire frequencies (P < 0.05). Microbial biomass C, total organic C, and total soil N were positively correlated with FQI (P < 0.05). This study shows that floristic quality and soil N pools are more strongly influenced by grazing than fire and that floristic quality can be an indicator of total soil C and N stocks in never cultivated lowland prairie.

Mapping fire effects on ash and soil properties. Current knowledge and future perspectives.

NASA Astrophysics Data System (ADS)

Pereira, Paulo; Cerda, Artemi; Strielko, Irina

2014-05-01

Fire has heterogeneous impacts on ash and soil properties, depending on severity, topography of the burned area, type of soil and vegetation affected, and meteorological conditions during and post-fire. The heterogeneous impacts of fire and the complex topography of wildland environments impose the challenge of understand fire effects at diverse scales in space and time. Mapping is fundamental to identify the impacts of fire on ash and soil properties because allow us to recognize the degree of the fire impact, vulnerable areas, soil protection and distribution of ash and soil nutrients, important to landscape recuperation. Several methodologies have been used to map fire impacts on ash soil properties. Burn severity maps are very useful to understand the immediate and long-term impacts of fire on the ecosystems (Wagtendonk et al., 2004; Kokaly et al., 2007). These studies normally are carried out with remote sensing techniques and study large burned areas. On a large scale it is very important to detect the most vulnerable areas (e.g. with risk of runoff increase, flooding, erosion, sedimentation and debris flow) and propose -if necessary- immediate rehabilitation measures. Post-fire rehabilitation measures can be extremely costly. Thus the identification of the most affected areas will reduce the erosion risks and soil degradation (Miller and Yool, 2002; Robichaud et al., 2007; Robichaud, 2009), as the consequent economical, social and ecological impacts. Recently, the United States Department of Agriculture created a field guide to map post-fire burn severity, based on remote sensing and Geographical Information Systems (GIS) technologies. The map produced should reflect the effects of fire on soil properties, and identify areas where fire was more severe (Parsons et al. 2010). Remote sensing studies have made attempts to estimate soil and ash properties after the fire, as hydrophobicity (Lewis et al., 2008), water infiltration (Finnley and Glenn, 2010), forest floor consumption (Lewis et al., 2011), ash cover (Robichaud et al., 2007) and other aspects related with soil as the vegetation factors that affect post-fire erosion risk (Fox et al., 2008). Field studies had also indented to estimate and map the impacts of fire in soil properties. Contrary to remote sensing studies, the mapping of fire effects on ash and soil properties in the field is specially carried out at small scale (e.g. slope or plot). The small scale resolution studies are important because identify small patterns that are normally ignored by remote sensing studies, but fundamental to understand the post-fire evolution of the burned areas. One of the important aspects of the small scale studies of fire effect on ash and soil properties is the great spatial variability, showing that the impact of fire is extremely heterogeneous in space and time (Outeiro et al., 2008; Pereira et al. in press). The small scale mapping of fire effects on soil properties normally is carried out using Geostatistical methods or using deterministic interpolation methods (Robichaud and Miller, 1999; Pereira et al., 2013). Several reports were published on the spatial distribution and mapping of ash and duff thickness (Robichaud and Miller, 1999; Pereira et al., 2013; Pereira et al. in press), fire severity (Pereira et al., 2014), ash chemical characteristics as total nitrogen (Pereira et al., 2010a), and ash extractable elements (Pereira et al., 2010b). Also, previous works mapped fire effects on soil temperature (Gimeno-Garcia et al., 2004), soil hydrophobicity (Woods et al., 2007), total nitrogen (Hirobe et al., 2003), phosphorous (Rodriguez et al., 2009) and major cations (Outeiro et al., 2008). It is important to integrate remote sensing and field based works of fire effects on ash and soil properties in order to have a better validation of the models predicted. The aim of this work is present the current knowledge about mapping fire effects in ash and soil properties at diverse scales and the future perspectives. References Finley, C.D., Glenn, N.F. (2010) Fire and vegetation type effects on soil hydrophobicity and infiltration in the sagebrussh-steppe: II. Hyperspectral analysis. Journal of Arid Environments, 74: 660-666. Fox, D.A., Maselli, F., Carrega, P. (2008) Using SPOT images and field sampling to map burn severity and vegetation factors affecting post-fire erosion risk. Catena, 75: 326-335. Gimeno-Garcia. E., Andreu., V., Rubio, J.L. (2004) Spatial patterns of soil temperatures during experiemntal fires. Geoderma, 118: 17-34. Hirobe, M., Tokushi, N., Wachrinrat, C., Takeda, H. (2003) Fire history influences on the spatial heterogeneity of soil nitrogen transformations in three adjacent stands in a dry tropical forest in Thailand. Plant and Soil, 249: 309-318. Kokaly, R.F., Rockwell, B.W., Haire, S.L., King, T.V.V. (2007) Characterization of post fire surface cover, soils, and burn severity at the Cerro Grande fire, New Mexico, using hyperspectral and multispectral remote sensing. Remote Sensing of the Environment, 106: 305-325. Lewis, S.A., Hudak, A.T., Ottmar, R.D., Robichaud, P.R., Lentile, L.B., Hood, S.M., Cronan, J.B., Morgan, P. (2012) Using hyperspectral imagery to estimate forest floor consumption from wildfire in boreal forests of Alaska. International Journal of Wildland Fire, 20: 255-271. Lewis, S.A., Robichaud, P.R., Frazier, B.E., Wu, J.Q., Laes, D.Y.M. (2008) Using hyperspectral imagery to predict post-wildfire soil repellency. Geomorphology, 98, 192-205. Miller, J.D., Yool, S. (2002) Mapping forest post-fire canopy consumption in several overstory types using multi-temporal Landsat TM and ETM data. Remote Sensing of the Environment, 82: 481-496. Outeiro, L., Aspero, F., Ubeda, X. (2008) Geostatistical methods to study spatial variability of soil cation after a prescribed fire and rainfall. Catena, 74: 310-320. Parsons, A., Robichaud, P.R., Lewis, S.A., Napper, C., Clark, J.T. (2010) Field guide for mapping post-fire soil burn severity. Gen. Tech. Rep. RMRS-GTR-243. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 49 p. Pereira, P. Úbeda X., Martin D A (2010b) Mapping wildfire effects on Ca2+ and Mg2+ released from ash. A microplot analysis, EGU General Assembly 2010, Geophysical Research Abstracts, 12,EGU 2010 - 30 Vienna. ISSN: 1607-7962. Pereira, P., Cerdà, A., Úbeda, X., Mataix-Solera, J. Arcenegui, V., Zavala, L. Modelling the impacts of wildfire on ash thickness in a short-term period, Land Degradation and Development, (In Press), DOI: 10.1002/ldr.2195 Pereira, P., Cerdà, A., Úbeda, X., Mataix-Solera, J., Jordan, A. Burguet, M. (2013) Spatial models for monitoring the spatio-temporal evolution of ashes after fire - a case study of a burnt grassland in Lithuania, Solid Earth, 4: 153-165. Pereira, P., Úbeda, X., Baltrenaite, E. (2010a) Mapping Total Nitrogen in ash after a Wildfire, a microplot analysis, Ekologija, 56 (3-4), 144-152. Pereira, P., Cerda, A., Ubeda, X., Mataix-Solera, J., Martin, D.A., Jordan, A., Martin, D.A., Mierauskas, P., Arcenegui, V., Zavala, L. (2014) Do fire severity effects change with the time?, What ash tell us, Flamma, 5: 23-27. Robichaud, P.R. (2009) Post-fire stabilization and rehabilitation. In: Cerda, A., Robichaud, P. (eds) Fire Effects on Soils and Restoration Strategies, Science Publishers, 299-320. Robichaud, P.R., Lewis, S.A., Laes, D.Y.M., Hudak, A.T., Kokaly, R.F., Zamudio, J.Z. (2007) Post-fire burn severity mapping with hyperspectral image unmixing. Remote Sensing of the Environment, 108: 467-480. Robichaud, P.R., Miller, S.M. (1999) Spatial interpolation and simulation of post-burn duff thickness after prescribed fire. International Journal of Wildland Fire, 9: 137-143. Rodriguez, A., Duran, J., Fernandez-Palacios, J.M., Gallardo, A. (2009) Short-term wildfire effects on the spatial pattern and scale of labile organic-N and inorganic-N and P pools. Forest Ecology and Management, 257: 739-746. Wagtendonk, J.W., Root, R.R., Key, C.H. (2004) Comparison of AVIRIS and Landsat ETM+ detection capabilities for burn severity. Remote Sensing of the Environment, 92: 397-408. Woods, S.W., Birkas, A., Ahl, R. (2007) Spatial variability of soil hydrophobicity after wildfires in Montana and Colorado. Geomorphology, 86: 465-479.

Estimated smoldering probability: a new tool for predicting ground fire in the organic soils on the North Carolina Coastal Plain

Treesearch

James Reardon; Gary Curcio

2011-01-01

In the Southeastern United States, fires in pocosin wetlands and other similar vegetation communities with deep organic soils are a serious concern to fire managers. Highly flammable shrubs, such as gallberry and fetterbush, and small evergreen trees, such as red and loblolly bay, create the potential for extreme surface fire behavior. Moreover, deep organic soils...

Wildfire Ash: Chemical Composition, Ash-Soil Interactions and Environmental Impacts

NASA Astrophysics Data System (ADS)

Brook, Anna; Hamzi, Seham; Wittenberg, Lea

2015-04-01

Of the five classical factors of soil formation, climate, parent material, topography, time, organisms, and recently recognized human activity, it is the latter factor which discretely includes fire and post-burn impact. However, it is considered that soil undergoing fire just experience a temporary removal of the top organic horizon, thus slightly modified and often labeled as 'temporarily disturbed' soil or soil 'under restoration/rehabilitation'. In fact the suggested seventh factor, post-burned produced ash, can act both dependently and independently of the other soil forming factors (Levin et al., 2013; Certini 2013). They are interdependent in cases where ash influences occur on time scales similar to 'natural' soil formation (Keesstra et ai., 2014) such as changes in vegetation. On the other hand, in post-fire areas a strong dependency is expected between soil-water retention mechanism, climate and topography. Wild-land fires exert many changes on the physical, chemical, mineralogical, biological, and morphological properties of soil that, in turn, affect the soil's hydrology and nutrient flux, modifying its ability to support vegetation and resist erosion. The ash produced by forest fires is a complex mixture composed of organic and inorganic particles characterized by vary physical-chemical and morphological properties. The importance of this study is straightforwardly related to the frequency and large-scales wildfires in Mediterranean region. In fact, wildfires are major environmental and land management concern in the world, where the number and severity of wildfires has increased during the past decades (Bodi, 2013). Certini (2013) assumed that cumulatively all of the vegetated land is burned in about 31 years annually affecting 330-430 Mha (over 3% of the Earth's surface) and wide range of land cover types worldwide including forests, peatlands, shrublands and grasslands. Whereas, the fire is identified as an important factor in soil formation, the produced ash has significant and not always constructive pedological, ecological, hydrological and geomorphological effects and impacts (Shakesby, 2011). Abundant scientific information is assembled either from control fires by collecting samples before and after wildfire event, or conducting laboratory experiments exanimating data under truly isolated conditions (Lugassi et al., 2013). However, an integration and synthesis of the knowledge about ash including deeper understanding of inter-correlation between chemical, physical and morphological compounds in open post-burn environment and its possible interactions in soil formation or impact on soil composition are highly needed. The main aim of the presented study was to advance the science of soil-fire relationship by recognizing the remains ash as a new soil-forming factor, on par with the traditionally recognized factors: parent material, topography, time, climate, organisms, and recently recognized human activity as the sixth factor. This research was conducted to develop new methods to assess impacts and quantify the contributions/influences of post-fire products, mainly ash, on soil composition and soil properties in post-burned environment. We conducted several controlled experiments using 40 soil samples (typical Mediterranean Rendzina soil, pH 6.84, a grayish-brown, humus- and free calcium carbonate- rich, intra-zonal). The samples include bare soils and different types and loads of forest litter, were exposed to different temperatures (200° C, 400° C and 600° C) in a muffle furnace for 2 hours (Pereira et al. 2011) as fire temperature plays a key role in determining ash properties. The ash produced at a low temperatures (50% carbon and retains many of the structural characteristics of the parent material. At higher temperatures, the residue ash is greyish, consisted of very fine particles that preserve almost none of the original structural characteristics of the fuel (Woods and Balfour, 2008) creating gradient of layered ash with diverse physicochemical properties. The obtained post-burned soils were processed as following: 1. loss of mass (ML); 2. ash layers sampling - the produced ash layers were collected separately; 3. grinding; 4. color - the Munsell colour chart; 5. spectroscopy- each sample was analysed by two spectrometer, first is the Ocean Optics USB4000 (0.35-1.05 μm) portable system across visible and near infrared (VNIR) region using contact Halogen illumination, second is the Bruker Tensor II (2.35-25 μm) across mid infrared (MIR) region by Furrier transform IR (FTIR) system using the Pike EasiDiff diffuse reflectance spectroscopy (DRS) optical bench; 6. pH and electrical conductivity (EC) including total dissolve solids (TDS) and salinity (S) measurements. The result of high concentration of carbonates, oxides, and hydroxides of basic cations decreasing EC levels caused by high pH (>8) there the CaCO3 surfaces are negatively charged and variation of mineralogical composition introducing very detailed list of minerals (high concentration of Nickeline NiAs, Cuprite Cu2O, Rehodochrosite MnCO3 and Nitrolite Na2Al2Si3O102H2O in the top-layers and mixtures e.g. Kaolinite/Smectite (85% Kaol.) Al2Si2O5(OH)4+(Na,Ca)0.33(Al,Mg)2Si4O10(OH)2nH2O and Mesolite + Hydroxyapophyllite Na2Ca2Al6Si9O308H2O + KCa4Si8O20(OH,F)8H2O between ash and post-burn top-soil layers. Bodí M.B., Muñoz-Santa I., Armero C., Doerr S.H., Mataix-Solera J., Cerdà A., 2013. Spatial and temporal variations of water repellency and probability of its occurrence in calcareous Mediterranean rangeland soils affected by fires. Catena, vol. 108, pp. 14-24. Certini G., Scalenghe R., Woods W.W., 2013. The impact of warfare on the soil environment. Earth-Science Reviews, vol. 127, pp. 1-15. Keesstra S.D., Temme A.J.A.M., Schoorl J.M., Visser S.M., 2014. Evaluating the hydrological component of new catchment-scale sediment delivery model LAPSUS-D. Geomorphology, vol. 212, pp. 97-107. Levin N., Levental S., Morag H., 2013. The effect of wildfires on vegetation cover and dune activity in Australia's desert dunes: a multisensor analysis International Journal of Wildland Fire, vol. 21 (4), pp. 459-475. Lugassi R., Ben-Dor E., Eshel G., 2013. Reflectance spectroscopy of soils post-heating'Assessing thermal alterations in soil minerals. Geoderma, vol. 231, pp. 268-279. Pereira P., Úbeda X., Martin D., Mataix-Solera J., Guerrero C. 2011. Effects of a low prescribed fire in ash water soluble elements in a Cork Oak (Quercus suber) forest located in Northeast of Iberian Peninsula, Environmental Research, vol. 111(2), pp. 237-247. Shakesby R.A., 2011. Post-wildfire soil erosion in the Mediterranean: Review and future research directions Earth Science Reviews, vol. 105, pp. 71-100. Woods, S.W., Balfour, V.N. 2010. The effects of soil texture and ash thickness on the post-fire hydrological response from ash-covered soils, Journal of Hydrology, vol. 393, pp. 274-286.

Soil Microbial Activity Responses to Fire in a Semi-arid Savannah Ecosystem Pre- and Post-Monsoon Season

NASA Astrophysics Data System (ADS)

Jimenez, J. R.; Raub, H. D.; Jong, E. L.; Muscarella, C. R.; Smith, W. K.; Gallery, R. E.

2017-12-01

Extracellular enzyme activities (EEA) of soil microorganisms can act as important proxies for nutrient limitation and turnover in soil and provide insight into the biochemical requirements of microbes in terrestrial ecosystems. In semi-arid ecosystems, microbial activity is influenced by topography, disturbances such as fire, and seasonality from monsoon rains. Previous studies from forest ecosystems show that microbial communities shift to similar compositions after severe fires despite different initial conditions. In semi-arid ecosystems with high spatial heterogeniety, we ask does fire lead to patch intensification or patch homogenization and how do monsoon rains influence the successional trajectories of microbial responses? We analyzed microbial activity and soil biogeochemistry throughout the monsoon season in paired burned and unburned sites in the Santa Rita Experimental Range, AZ. Surface soil (5cm) from bare-ground patches, bole, canopy drip line, and nearby grass patches for 5 mesquite trees per site allowed tests of spatiotemporal responses to fire and monsoon rain. Microbial activity was low during the pre-monsoon season and did not differ between the burned and unburned sites. We found greater activity near mesquite trees that reflects soil water and nutrient availability. Fire increased soil alkalinity, though soils near mesquite trees were less affected. Soil water content was significantly higher in the burned sites post-monsoon, potentially reflecting greater hydrophobicity of burned soils. Considering the effects of fire in these semi-arid ecosystems is especially important in the context of the projected changing climate regime in this region. Assessing microbial community recovery pre-, during, and post-monsoon is important for testing predictions about whether successional pathways post-fire lead to recovery or novel trajectories of communities and ecosystem function.

Soil Data from a Moderately Well and Somewhat Poorly Drained Fire Chronosequence near Thompson, Manitoba, Canada

USGS Publications Warehouse

Manies, K.L.; Harden, J.W.; Veldhuis, Hugo; Trumbore, Sue

2006-01-01

The U.S. Geological Survey project Fate of Carbon in Alaskan Landscapes (FOCAL) is studying the effect of fire and soil drainage on soil carbon storage in the boreal forest. As such this group was invited to be a part of a NSF-funded project (Fire, Ecosystem and Succession - Experiment Boreal or FIRES-ExB) to study the carbon balance of sites that varied in age (time since fire) and soil drainage in the Thompson, Manitoba, Canada region. This report describes the location of our FIRES-ExB sampling sites as well as the procedures used to describe, sample, and analyze the soils. This report also contains data tables with sample related information including, but not limited to, field descriptions, bulk density, particle size distribution, moisture content, carbon (C) concentration, nitrogen (N) concentration, isotopic data for C, and major, minor and trace elemental concentration.

Soils of Mountainous Forests and Their Transformation under the Impact of Fires in Baikal Region

NASA Astrophysics Data System (ADS)

Krasnoshchekov, Yu. N.

2018-04-01

Data on postpyrogenic dynamics of soils under mountainous taiga cedar ( Pinus sibirica) and pine ( Pinus sylvestris) forests and subtaiga-forest-steppe pine ( Pinus sylvestris) forests in the Baikal region are analyzed. Ground litter-humus fires predominating in this region transform the upper diagnostic organic soil horizons and lead to the formation of new pyrogenic organic horizons (Opir). Adverse effects of ground fires on the stock, fractional composition, and water-physical properties of forest litters are shown. Some quantitative parameters of the liquid and solid surface runoff in burnt areas related to the slope gradient, fire intensity, and the time passed after the fire are presented. Pyrogenic destruction of forest ecosystems inevitably induces the degradation of mountainous soils, whose restoration after fires takes tens of years. The products of soil erosion from the burnt out areas complicate the current situation with the pollution of coastal waters of Lake Baikal.

Modeling the effects of fire severity and climate warming on active layer and soil carbon dynamics of black spruce forests across the landscape in interior Alaska

USGS Publications Warehouse

Genet, H.; McGuire, Anthony David; Barrett, K.; Breen, A.; Euskirchen, E.S.; Johnstone, J.F.; Kasischke, E.S.; Melvin, A.M.; Bennett, A.; Mack, M.C.; Rupp, T.S.; Schuur, A.E.G.; Turetsky, M.R.; Yuan, F.

2013-01-01

There is a substantial amount of carbon stored in the permafrost soils of boreal forest ecosystems, where it is currently protected from decomposition. The surface organic horizons insulate the deeper soil from variations in atmospheric temperature. The removal of these insulating horizons through consumption by fire increases the vulnerability of permafrost to thaw, and the carbon stored in permafrost to decomposition. In this study we ask how warming and fire regime may influence spatial and temporal changes in active layer and carbon dynamics across a boreal forest landscape in interior Alaska. To address this question, we (1) developed and tested a predictive model of the effect of fire severity on soil organic horizons that depends on landscape-level conditions and (2) used this model to evaluate the long-term consequences of warming and changes in fire regime on active layer and soil carbon dynamics of black spruce forests across interior Alaska. The predictive model of fire severity, designed from the analysis of field observations, reproduces the effect of local topography (landform category, the slope angle and aspect and flow accumulation), weather conditions (drought index, soil moisture) and fire characteristics (day of year and size of the fire) on the reduction of the organic layer caused by fire. The integration of the fire severity model into an ecosystem process-based model allowed us to document the relative importance and interactions among local topography, fire regime and climate warming on active layer and soil carbon dynamics. Lowlands were more resistant to severe fires and climate warming, showing smaller increases in active layer thickness and soil carbon loss compared to drier flat uplands and slopes. In simulations that included the effects of both warming and fire at the regional scale, fire was primarily responsible for a reduction in organic layer thickness of 0.06 m on average by 2100 that led to an increase in active layer thickness of 1.1 m on average by 2100. The combination of warming and fire led to a simulated cumulative loss of 9.6 kgC m−2 on average by 2100. Our analysis suggests that ecosystem carbon storage in boreal forests in interior Alaska is particularly vulnerable, primarily due to the combustion of organic layer thickness in fire and the related increase in active layer thickness that exposes previously protected permafrost soil carbon to decomposition.

Long term consequences of a controlled slash burn and slash mastication to soil moisture and CO2 at a southern Colorado site

Treesearch

W. J. Massman; J. M. Frank; A. E. Jimenez Esquilin; M. E. Stromberger; W. D. Shepperd

2006-01-01

Thinning of forest stands is frequently used to reduce the risk of catastrophic fire. But thinning requires that the refuse (or slash) be removed from the site, which can be done either by burning it or by mastication and dispersal. Either method has long term consequences to the soil and to soil moisture and soil CO2 levels. For example, after the initial drying of...

Post-fire erosion control mulches alter belowground processes and nitrate reductase activity of a perennial forb, heartleaf arnica (Arnica cordifolia)

Treesearch

Erin M. Berryman; Penelope Morgan; Peter R. Robichaud; Deborah Page-Dumroese

2014-01-01

Four years post-wildfire, we measured soil and plant properties on hillslopes treated with two different mulches (agricultural wheat straw and wood strands) and a control (unmulched, but burned). Soil total N was about 40% higher and microbial respiration of a standard wood substrate was nearly twice as high in the mulched plots compared to the unmulched plots. Greater...

In situ soil temperature and heat flux measurements during controlled surface burns at a southern Colorado forest site

Treesearch

W. J. Massman; J. M. Frank; W. D. Shepperd; M. J. Platten

2003-01-01

This study presents in situ soil temperature measurements at 5-6 depths and heat flux measurements at 2-5 depths obtained during the fall/winter of 2001/ 2002 at seven controlled (surface) fires within a ponderosa pine forest site at the Manitou Experimental Forest in central Colorado. Six of these burns included three different (low, medium, and high) fuel loadings...

Analyzing the vegetation response under different treatments after wildfires in NE Spain

NASA Astrophysics Data System (ADS)

León, Javier; Cerdà, Artemi; Badía, David; Echeverría, Maite; Martí, Clara

2014-05-01

Fire is a natural factor of landscape evolution in Mediterranean ecosystems. The socio-economic changes that occurred in the last decades have contributed to an increase in forest fires (Shakesby, 2011). There was found a change in the fire regimes in terms of frequency, size, seasonality, recurrence as well as fire intensity and severity (Keeley, 2009), which resulted in severe effects on soils, water and vegetation (Guénon et al., 2013). Fire affects soil properties directly by the heat impact (Aznar et al., 2013), and the ash cover (Cerdà and Doerr, 2008) and the reduction of the plant cover (Neary et al., 1999). The lack of vegetation and the heating promotes changes in the soil organic matter content (González-Pérez et al., 2004), on the structural stability (Mataix-Solera et al., 2011), on the hydrophobic response (Bodí et al., 2012), and on the infiltration capacity (Cerdà, 1998a). This is why the vegetation cover and the litter are key factors on soil erosion after forest fires (Prats et al., 2013). Besides, the ash plays an important paper in the soil protection after the forest fire and after the first storms and winds (León et al., 2013; Pereira et al., 2013). The objective of this experiment is to asses the vegetation response after a forest fire and the impact of vegetation recovery on soil erosion. The experiment consisted in a sampling of a linear transect of 10 m with samples each 2 m, under different slope position and aspect. To measure the soil erosion rates we used rainfall simulation experiments (León et al., 2013). The experiments were carried in Castejón (UTM 30T, X671106, Y4644584) in a forest burned in 2008, in the Zuera Mountains, both located in the north of Zaragoza province (NE Spain). The soils on limestone parent material are Rendzic Phaeozem (IUSS, 2007) and the texture of Ah horizons of soils developed on limestone is sandy-loam (Badía et al., 2013). The result shows fast and successful vegetation regeneration in the north-facing slopes, and a delayed recovery on the south-facing slopes. The soil erosion control treatments shown a very efficient response when Chipped branches covered the soil. References Aznar, J.M., González-Pérez, J.A., Badía, D., Martí, C. 2013. At what depth are the properties of a Gypseous forest topsoil affected by burning?. Land Degradation and Development, DOI: 10.1002/ldr.2258 Badía, D., Martí, C., Aznar, J.M., León, J. 2013. Influence of slope and parent rock on soil genesis and classification in semiarid mountainous environments. Geoderma 193-194: 13-21, doi: http://dx.doi.org/10.1016/j.geoderma.2012.10.020. Bodí, M.B., Doerr, S.H., Cerdà, A., and Mataix-Solera, J. 2012. Hydrological effects of a layer of vegetation ash on underlying wettable and water repellent soil. Geoderma, 191: 14-23. Cerdà, A. 1998a. Postfire dynamics of erosional processes under mediterranean climatic conditions. Zeitschrift für Geomorphologie, 42 (3) 373-398. Cerdà, A. 1998b. The influence of aspect and vegetation on seasonal changes in erosion under rainfall simulation on a clay soil in Spain. Canadian Journal of Soil Science 78, 321-330. Cerdà, A., Doerr, S.H., 2008. The effect of ash and needle cover on surface runoff and ersion in the inmediate post-fire period. Catena 74, 256-263. González-Pérez, J.A., González-Vila, F.J., Almendros, G., Knicker, H. 2004. The effect of fire on soil organic matter - a review. Enviroment International, 30: 855-870. Guénon, R., Vennetier, M., Dupuy, N., Roussos, S., Pailler, A., Gros, R. 2013. Trends in recovery of Mediterranean soil chemical properties and microbial activities after infrequent and frequent wildfires. Land Degradation & Development, 24: 115-128, DOI: 10.1002/ldr.1109. Keeley, J.E. 2009. Fire intensity, fire severity and burn severity: a brief review and suggests usage. International Journal of Wildland Fire, 18: 116-126. León, J., Bodí, M.B., Cerdà, A., Badía, D., 2013. The contrasted response of ash to wetting: The effects of ash type, thickness and rainfall events. Geoderma 209-210, 143-152. Mataix-Solera, J., Cerdà, A., Arcenegui, V., Jordán, A., Zavala, L.M., 2011. Fire effects on soil aggregation: a review. Earth-Science Reviews, 109: 44-60. Neary, D.G., Klopatek, C.C., DeBano, L.F., Ffolliot, P. 1999. Fire effects on belowground sustainability: a review and synthesis. Forest Ccol. Manag., 122: 51-71. Pereira, P., Cerdà, A., Úbeda, X., Mataix-Solera, J., Martin, D., Jordán, A., Burguet, M. 2013. Spatial models for monitoring the spatio-temporal evolution of ashes after fire - a case study of a burnt grassland in Lithuania. Solid Earth, 4: 153-165. Prats, S.A., Malvar, M.C., Simões-Vieira, D.C., MacDonald, L., and Keizer, J.J. 2013. Effectiveness of hydromulching to reduce runoff and erosion in a recently burnt pine plantation in central Portugal. Land Degradation & Development, DOI: 10.1002/ldr.2236. Shakesby, R.A. 2011. Post-wildfire soil erosion in the Mediterranean: Review and future research directions. Earth Science Reviews, 105, 71-100.

Effects of fire on chaparral soils in Arizona and California and postfire management implications

Treesearch

Leonard F. DeBano

1989-01-01

Wildfires and prescribed burns are common throughout Arizona and California chaparral. Predicting fire effects requires understanding fire behavior, estimating soil heating, and predicting changes in soil properties. Substantial quantities of some nutrients, particularly nitrogen and phosphorus, are lost directly during combustion. Highly available nutrients released...

Modeling forest development after fire disturbance: Climate, soil organic layer, and nitrogen jointly affect forest canopy species and long-term ecosystem carbon accumulation in the North American boreal forest

NASA Astrophysics Data System (ADS)

Trugman, A. T.; Fenton, N.; Bergeron, Y.; Xu, X.; Welp, L.; Medvigy, D.

2015-12-01

Soil organic layer dynamics strongly affect boreal forest development after fire. Field studies show that soil organic layer thickness exerts a species-specific control on propagule establishment in the North American boreal forest. On organic soils thicker than a few centimeters, all propagules are less able to recruit, but broadleaf trees recruit less effectively than needleleaf trees. In turn, forest growth controls organic layer accumulation through modulating litter input and litter quality. These dynamics have not been fully incorporated into models, but may be essential for accurate projections of ecosystem carbon storage. Here, we develop a data-constrained model for understanding boreal forest development after fire. We update the ED2 model to include new aspen and black spruce species-types, species-specific propagule survivorship dependent on soil organic layer depth, species-specific litter decay rates, dynamically accumulating moss and soil organic layers, and nitrogen fixation by cyanobacteria associated with moss. The model is validated against diverse observations ranging from monthly to centennial timescales and spanning a climate gradient in Alaska, central Canada, and Quebec. We then quantify differences in forest development that result from changes in organic layer accumulation, temperature, and nitrogen. We find that (1) the model accurately reproduces a range of observations throughout the North American boreal forest; (2) the presence of a thick organic layer results in decreased decomposition and decreased aboveground productivity, effects that can increase or decrease ecosystem carbon uptake depending on location-specific attributes; (3) with a mean warming of 4°C, some forests switch from undergoing succession to needleleaf forests to recruiting multiple cohorts of broadleaf trees, decreasing ecosystem accumulation by ~30% after 300 years; (4) the availability of nitrogen regulates successional dynamics such than broadleaf species are less able to compete with needleleaf trees under low nitrogen regimes. We conclude that a joint regulation between the soil organic layer, temperature, and nitrogen will likely play an important role in influencing boreal forests development after fire in future climates, and should be represented in models.

Temperature peaks affect fire-induced soil water repellency, infiltration and erosion risk of Mediterranean shrublands. Implications for water and sediment connectivity

NASA Astrophysics Data System (ADS)

Jordán, Antonio; Zavala, Lorena M.; Gordillo-Rivero, Ángel J.; Miriam, Miriam; Keesstra, Saskia; Cerdà, Artemi

2017-04-01

We know that the impact of fire on soil water repellency varies largely with the availability of water and physical and chemical soil properties, as well as the intensity of pre-existing hydrophobicity. However, there are few studies that relate the intensity of post-fire soil hydrophobicity and its persistence to the intensity and duration of thermal peaks occurring during fire. Fundamentally, this is due to the difficulty of quantifying these factors in situ, so that experimental fires are an extremely useful tool. The objective of this work was to study the impact of the intensity and duration of the thermal peaks observed during an experimental fire in the hydrophobicity of previously wet or slightly hydrophobic soils and the consequences of these changes on infiltration, runoff and soil loss (through rainfall simulation) in the immediate (30 days) and medium-term (1 year) post-fire period. In general, soil water repellency increased in all cases, although high temperatures and residence times of moderate thermal peaks caused the greatest impact. Although infiltration rates determined by mini-disk infiltrometer with water generally declined, no significant changes were observed in the same measurement with ethanol (which negates the effect of hydrophobicity).

The Effects of Fire on the Function of the 200-BP-1 Engineered Surface Barrier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ward, Anderson L.; Link, Steven O.; Hasan, Nazmul

2009-09-01

A critical unknown in use of barrier technology for long-term waste isolation is performance after a major disturbance especially when institutional controls are intact, but there are no resources to implement corrective actions. The objective of this study was to quantify the effects of wild fire on alterations the function of an engineered barrier. A controlled burn September 26, 2008 was used to remove all the vegetation from the north side of the barrier. Flame heights exceeded 9 m and temperatures ranged from 250 oC at 1.5 cm below the surface to over 700 oC at 1 m above themore » surface. Post-fire analysis of soil properties show significant decreases in wettability, hydraulic conductivity, air entry pressure, organic matter, and porosity relative to pre-fire conditions whereas dry bulk density increased. Decreases in hydraulic conductivity and wettabilty immediately after the fire are implicated in a surface runoff event that occurred in January 2009, the first in 13 years. There was a significant increase in macro-nutrients, pH, and electrical conductivity. After one year, hydrophobicity has returned to pre-burn levels with only 16% of samples still showing signs of decreased wettability. Over the same period, hydraulic conductivity and air entry pressure returned to pre-burn levels at one third of the locations but remained identical to values recorded immediately after the fire at the other two thirds. Soil nutrients, pH, and electrical conductivity remain elevated after 1 year. Species composition on the burned surface changed markedly from prior years and relative to the unburned surface and two analog sites. An increase in the proportion of annuals and biennials is characteristic of burned surfaces that have become dominated by ruderal species. Greenhouse seedling emergence tests conducted to assess the seed bank of pre- and post-burn soils and of two analog sites at the McGee Ranch show no difference in the number of species emerging from soils collected before and after the fire. However, there were fewer species emerging from the seed bank on the side slopes and more species emerging from two analog sites. Leaf area index measures confirmed the substantial differences in plant communities after fire. Xylem pressure potential were considerably higher on the burned half of the barrier in September 2009 suggesting that not all the water in the soil profile will be removed before the fall rains begin. The results of this study are expected to contribute to a better understanding of barrier performance after major disturbances in a post-institutional control environment. Such an understanding is needed to enhance stakeholder acceptance regarding the long-term efficacy of engineered barriers. This study will also support improvements in the design of evapotranspiration (ET) and hybrid (ET + capacitive) barriers and the performance monitoring systems.« less

Soil and vegetation changes in a pinyon-juniper area in central Arizona after prescribed fire

Treesearch

Steven T. Overby; Will H. Moir; George T. Robertson

2000-01-01

Prescribed fire has been used as an inexpensive and rapid method for disposing of slash following fuelwood sales in pinyon-juniper sites. Soil heating during a fire has a direct effect on soil nutrients and microbial activity. The potential for understory cover quantity and quality, along with soil nutrient changes should be the determining factors in management...

BOREAS TGB-12 Soil Carbon and Flux Data of NSA-MSA in Raster Format

NASA Technical Reports Server (NTRS)

Hall, Forrest G. (Editor); Knapp, David E. (Editor); Rapalee, Gloria; Davidson, Eric; Harden, Jennifer W.; Trumbore, Susan E.; Veldhuis, Hugo

2000-01-01

The BOREAS TGB-12 team made measurements of soil carbon inventories, carbon concentration in soil gases, and rates of soil respiration at several sites. This data set provides: (1) estimates of soil carbon stocks by horizon based on soil survey data and analyses of data from individual soil profiles; (2) estimates of soil carbon fluxes based on stocks, fire history, drain-age, and soil carbon inputs and decomposition constants based on field work using radiocarbon analyses; (3) fire history data estimating age ranges of time since last fire; and (4) a raster image and an associated soils table file from which area-weighted maps of soil carbon and fluxes and fire history may be generated. This data set was created from raster files, soil polygon data files, and detailed lab analysis of soils data that were received from Dr. Hugo Veldhuis, who did the original mapping in the field during 1994. Also used were soils data from Susan Trumbore and Jennifer Harden (BOREAS TGB-12). The binary raster file covers a 733-km 2 area within the NSA-MSA.

Soil temperature and moisture fluctuations during and after prescribed fire in mixed-oak forests, USA

Treesearch

Louis R. Iverson; Todd F. Hutchinson; Todd F. Hutchinson

2002-01-01

Prescribed fires were conducted in March 1999, in mixed-oak forests in Vinton County, Ohio, USA, that had been burned either once in 1996 or annually from 1996 to 1999. During the fires, seven electronic sensors recorded soil temperatures every 2 seconds at a depth of 1 cm. Following the fires, soil temperatures were monitored with 12 sensors on burned and unburned...

Fire effects on soils in Lake States forests: A compilation of published research to facilitate long-term investigations

Treesearch

Jessica Miesel; P. Goebel; R. Corace; David Hix; Randall Kolka; Brian Palik; David Mladenoff

2012-01-01

Fire-adapted forests of the Lake States region are poorly studied relative to those of the western and southeastern United States and our knowledge base of regional short- and long-term fire effects on soils is limited. We compiled and assessed the body of literature addressing fire effects on soils in Lake States forests to facilitate the re-measurement of previous...

Soils of postpyrogenic larch stands in Central Siberia: Morphology, physicochemical properties, and specificity of soil organic matter

NASA Astrophysics Data System (ADS)

Startsev, V. V.; Dymov, A. A.; Prokushkin, A. S.

2017-08-01

Morphological features, physicochemical properties, and specific characteristics of the organic matter of cryozems (Cryosols) under postpyrogenic larch forests affected by fires 2, 6, 22, 55, and 116 years ago are considered. The morphological changes in the soils affected by fires are manifested by the burning of the upper organic horizons with preservation of pyrogenic features in the soils for more than a century after the fire. In the first years (2 and 6 years) after the fire, the acidity of the organic horizons and their base saturation become lower. The postpyrogenic soils are characterized by the smaller contribution of the organic horizons to the total pools of soil organic carbon. In the studied cryozems, the organic carbon content is correlated with the contents of oxalate-extractable iron and aluminum. A decrease in the content of water-soluble organic compounds in the soils is observed after the fires; gradually, their content increases upon restoration of the ground cover.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Genet, Helene; McGuire, A. David; Barrett, K.

There is a substantial amount of carbon stored in the permafrost soils of boreal forest ecosystems, where it is currently protected from decomposition. The surface organic horizons insulate the deeper soil from variations in atmospheric temperature. The removal of these insulating horizons through consumption by fire increases the vulnerability of permafrost to thaw, and the carbon stored in permafrost to decomposition. In this study we ask how warming and fire regime may influence spatial and temporal changes in active layer and carbon dynamics across a boreal forest landscape in interior Alaska. To address this question, we (1) developed and testedmore » a predictive model of the effect of fire severity on soil organic horizons that depends on landscape-level conditions and (2) used this model to evaluate the long-term consequences of warming and changes in fire regime on active layer and soil carbon dynamics of black spruce forests across interior Alaska. The predictive model of fire severity, designed from the analysis of field observations, reproduces the effect of local topography (landform category, the slope angle and aspect and flow accumulation), weather conditions (drought index, soil moisture) and fire characteristics (day of year and size of the fire) on the reduction of the organic layercaused by fire. The integration of the fire severity model into an ecosystem process-based model allowed us to document the relative importance and interactions among local topography, fire regime and climate warming on active layer and soil carbon dynamics. Lowlands were more resistant to severe fires and climate warming, showing smaller increases in active layer thickness and soil carbon loss compared to drier flat uplands and slopes. In simulations that included the effects of both warming and fire at the regional scale, fire was primarily responsible for a reduction in organic layer thickness of 0.06 m on average by 2100 that led to an increase in active layer thickness of 1.1 m on average by 2100. The combination of warming and fire led to a simulated cumulative loss of 9.6 kgC m 2 on average by 2100. Our analysis suggests that ecosystem carbon storage in boreal forests in interior Alaska is particularly vulnerable, primarily due to the combustion of organic layer thickness in fire and the related increase in active layer thickness that exposes previously protected permafrost soil carbon to decomposition.« less

25 CFR 216.7 - Approval of mining plan.

Code of Federal Regulations, 2014 CFR

2014-04-01

... suitable map, or aerial photograph showing the topography, the area covered by the permit or lease, the... as to reduce soil erosion and sedimentation and to prevent the pollution of receiving waters; (6) A description of measures to be taken to prevent or control fire, soil erosion, pollution of surface and ground...

25 CFR 216.7 - Approval of mining plan.

Code of Federal Regulations, 2012 CFR

2012-04-01

... suitable map, or aerial photograph showing the topography, the area covered by the permit or lease, the... as to reduce soil erosion and sedimentation and to prevent the pollution of receiving waters; (6) A description of measures to be taken to prevent or control fire, soil erosion, pollution of surface and ground...

25 CFR 216.7 - Approval of mining plan.

Code of Federal Regulations, 2013 CFR

2013-04-01

... suitable map, or aerial photograph showing the topography, the area covered by the permit or lease, the... as to reduce soil erosion and sedimentation and to prevent the pollution of receiving waters; (6) A description of measures to be taken to prevent or control fire, soil erosion, pollution of surface and ground...

The study of soils and vegetation transformation due fire disturbances in remote areas through scenario modelling of observed hydrological response to fire impact

NASA Astrophysics Data System (ADS)

Nesterova, Natalia; Semenova, Olga; Lebedeva, Luidmila

2015-04-01

Large territories of Siberia and Russian Far East are the subject to frequent forest fires. Often there is no information available about fire impact except its timing, areal distribution and qualitative characteristics of fire severity. Observed changes of hydrological response in burnt watersheds can be considered as indirect evidence of soil and vegetation transformation due to fire impact. In our study we used MODIS Fire products to detect spatial distribution of fires in Transbaikal and Far East regions of Russia in 2000 - 2012 period. Small and middle-size watersheds (with area up to 10000 km2) affected by extensive (burn area not less than 20 %) fires were chosen. We analyzed available hydrological data (measured discharges in watersheds outlets) for chosen basins. In several cases apparent hydrological response to fire was detected. To investigate main factors causing the change of hydrologic regime after fire several scenarios of soil and vegetation transformation were developed for each watershed under consideration. Corresponding sets of hydrological model parameters describing those transformations were elaborated based on data analysis and post-fire landscape changes as derived from a literature review. We implied different factors such as removal of organic layer, albedo changes, intensification of soil thaw (in presence of permafrost and seasonal soil freezing), reduction of infiltration rate and evapotranspiration, increase of upper subsurface flow fraction in summer flood events following the fire and others. We applied Hydrograph model (Russia) to conduct simulation experiments aiming to reveal which landscape changes scenarios were more plausible. The advantages of chosen hydrological model for this study are 1) that it takes into consideration thermal processes in soils which in case of permafrost and seasonal soil freezing presence can play leading role in runoff formation and 2) that observable vegetation and soil properties are used as its parameters allowing minimal resort to calibration. The model can use dynamic set of parameters performing preassigned abrupt and/or gradual changes of landscape characteristics. Interestingly, based on modelling results it can be concluded that depending on dominant landscape different aspects of soil and vegetation cover changes may influence runoff formation in contrasting way. The results of the study will be reported.

Desertification and other ecological impacts produced by the historic Rodeo-Chediski Wildfire of 2000, Arizona, USA

NASA Astrophysics Data System (ADS)

Neary, D.; Ffolliott, P.; Stropki, C.

2009-04-01

The Rodeo-Chediski Wildfire - the largest in Arizona's history - damaged or destroyed ecosystem resources and disrupted ecosystem functioning in a largely mosaic pattern throughout the ponderosa pine (Pinus ponderosa) forests exposed to the burn. Impacts of this wildfire on tree overstories were studied on two watersheds in the area burned; one watershed burned by a high severity (stand-replacing) fire, while the other watershed burned by a low severity (stand-modifying) fire. The Rodeo-Chediski wildfire damaged or destroyed ecosystem resources and disrupted the ecological functioning on much of the 189,015 ha impacted by the burning. Intermingling chaparral shrub communities and pinyon-juniper woodlands at lower elevations and ponderosa pine forests at high elevations were located within the burned area. The wildfire was caused by two human ignitions that merged into one inferno. The Rodeo Fire was started by an arsonist on June 18, 2002, while the Chediski Fire was ignited as a signal fire by a stranded motorist on June 20th. The two fires merged on June 26, 2002, to become the Rodeo-Chediski Wildfire. The combined wildfires were contained on July 7th at a suppression (firefighting) cost of about €37.9 million (USA 50 million). However, the estimated costs associated with property losses; losses of ecosystem, anthropological, and cultural resources; and post-fire rehabilitation efforts increased the costs of the wildfire to over €114 million (USA 150 million). About one-half of the total area that was burned by the Rodeo-Chediski Wildfire experienced a high-severity fire, other areas burned at a low- to medium-severity fire, and still other areas were largely unburned according to a Burned Area Emergency Rehabilitation (BAER) report and fire severity map prepared shortly after containment of the wildfire. A mosaic of areas burned at varying fire severities within intermingling unburned areas resulted. Post-fire rehabilitation efforts, including establishment of water bars, wattles, k-rails, and aerial seeding and mulching of herbaceous plants to mitigate that anticipated accelerated post-fire soil erosion, began immediately after the fire was extinguished and it was declared safe for people to enter the burned area and initiate rehabilitation. An assessment of the impacts of the Rodeo-Chediski wildfire on soil erosion was carried out on two watersheds situated at the headwaters of the Little Colorado River. One of the watersheds experienced a high severity burn and the other a low-to-medium severity burn. Estimates of soil erosion on a watershed-basis and relative to physiographic characteristics on the two watersheds following the (a) high-intensity summer monsoonal rains and (2) low-intensity winter precipitation and spring snowmelt-runoff events are presented and compared with estimates of soil erosion following other wildfires in the region. Monitoring of soil erosion and other hydrologic and ecological parameters is continuing to obtain a longer, more comprehensive picture of the impacts of this catastrophic wildfire event. The Rodeo-Chediski Wildfire altered the species composition and impacted the production of herbaceous plants on the burned watersheds studied. Effects of the post-fire vegetation changes reduced the capabilities of watersheds to support livestock and some of the other larger herbivores in the region. When these watersheds will return to pre-fire conditions is largely unknown. Not only must the forage resources be restored but the magnitude of post-fire soil erosion and accompanying nutrient losses must be mitigated. Post-fire rehabilitation efforts including the seeding of herbaceous species and installation of controls to reduce soil erosion and sedimentation processes have helped to accelerate this recovery to some extent. A much longer time will obviously be required for severely burned areas to recover than those areas burned by at a low severity. Portions of the latter have already returned to pre-fire conditions.

Decomposers and the fire cycle in a phryganic (East Mediterranean) ecosystem.

PubMed

Arianoutsou-Faraggitaki, M; Margaris, N S

1982-06-01

Dehydrogenase activity, cellulose decomposition, nitrification, and CO2 release were measured for 2 years to estimate the effects of a wildfire over a phryganic ecosystem. In decomposers' subsystem we found that fire mainly affected the nitrification process during the whole period, and soil respiration for the second post-fire year, when compared with the control site. Our data suggest that after 3-4 months the activity of microbial decomposers is almost the same at the two sites, suggesting that fire is not a catastrophic event, but a simple perturbation common to Mediterranean-type ecosystems.

Temporal Changes Rather than Long-Term Repeated Burning Predominately Control the Shift in the Abundance of Soil Denitrifying Community in an Australian Sclerophyll Forest.

PubMed

Liu, Xian; Chen, C R; Hughes, J M; Wang, W J; Lewis, Tom

2017-01-01

To understand the temporal dynamics of soil bacterial denitrifying community in response to long-term prescribed burning and its resilience and recovery following a fire, a wet sclerophyll forest study site under two treatments (2 yearly burning (2YB) and no burning (NB)) and with 40-year-old burning history was used. Similar temporal patterns in the abundance of total (16S rRNA) and denitrifying (narG, nirK, nirS, nosZ) bacteria between two burning treatments revealed strong temporal influences. The magnitude of burning impacts on the abundance of 16S rRNA and denitrification genes was smaller compared with the impact of sampling time, but significant burning and temporal impacts were recorded for all (P < 0.001)-except for the nirS gene. Impacts of prescribed fire on the abundance of soil denitrifying community could be observed immediately after fire, and this impact diminished over a 24-month period prior to the next prescribed burning event. In conclusion, temporal changes govern the fluctuations of the abundance of soil denitrifying genes over the sampling period and the denitrifying community can recover after fire, suggesting that this community is resilient to the effects of prescribed burning. A combination of biotic and abiotic factors may account for the different temporal dynamics of denitrification gene abundance.

Fire-induced water repellency: An erosional factor in wildland environments

Treesearch

Leonard F. DeBano

2000-01-01

Watershed managers and scientists throughout the world have been aware of fire-induced water-repellent soils for over three decades. Water repellency affects many hydrologic processes, including infiltration, overland flow, and surface erosion (rill and sheet erosion). This paper describes; the formation of fire-induced water-repellent soils, the effect of soil water...

Measuring soil and tree temperatures during prescribed fires with thermocouple probes

Treesearch

Stephen S. Sackett; Sally M. Haase

1992-01-01

Soil and cambium temperatures must be known to ascertain certain effects of prescribed fires on trees. Thermocouple-based systems were devised for measuring soil and cambium temperatures during prescribed fires. The systems, which incorporate both commercially available and custom components, perform three basic functions: data collection, data retrieval, and data...

Ash in fire affected ecosystems

NASA Astrophysics Data System (ADS)

Pereira, Paulo; Jordan, Antonio; Cerda, Artemi; Martin, Deborah

2015-04-01

Ash in fire affected ecosystems Ash lefts an important footprint in the ecosystems and has a key role in the immediate period after the fire (Bodi et al., 2014; Pereira et al., 2015). It is an important source of nutrients for plant recover (Pereira et al., 2014a), protects soil from erosion and controls soil hydrological process as runoff, infiltration and water repellency (Cerda and Doerr, 2008; Bodi et al., 2012, Pereira et al., 2014b). Despite the recognition of ash impact and contribution to ecosystems recuperation, it is assumed that we still have little knowledge about the implications of ash in fire affected areas. Regarding this situation we wanted to improve our knowledge in this field and understand the state of the research about fire ash around world. The special issue about "The role of ash in fire affected ecosystems" currently in publication in CATENA born from the necessity of joint efforts, identify research gaps, and discuss future cooperation in this interdisciplinary field. This is the first special issue about fire ash in the international literature. In total it will be published 10 papers focused in different aspects of the impacts of ash in fire affected ecosystems from several parts of the world: • Fire reconstruction using charcoal particles (Burjachs and Espositio, in press) • Ash slurries impact on rheological properties of Runoff (Burns and Gabet, in press) • Methods to analyse ash conductivity and sorbtivity in the laboratory and in the field (Balfour et al., in press) • Termogravimetric and hydrological properties of ash (Dlapa et al. in press) • Effects of ash cover in water infiltration (Leon et al., in press) • Impact of ash in volcanic soils (Dorta Almenar et al., in press; Escuday et al., in press) • Ash PAH and Chemical extracts (Silva et al., in press) • Microbiology (Barreiro et al., in press; Lombao et al., in press) We believe that this special issue will contribute importantly to the better understanding of the role of ash in fire affected areas. Acknowledgments The 'Litfire' Project (MIP-048/2011; 181 Pereira) funded by the Lithuanian Research Council, Soil quality, erosion control and plant cover recovery under different post-firemanagement scenarios (POSTFIRE), funded by the Spanish Ministry of Economy and Competitiveness (CGL2013-47862-C2-1-R), Preventing and Remediating Degradation of Soils in Europe Through Land Care (RECARE) funded by the European Commission (FP7-ENV-2013-TWO STAGE) and European Research Project LEDDRA (243857) and COST action ES1306 (Connecting European connectivity research). References Balfour, V.N., Determining wildfire ash saturated hydraulic conductivity and sorptivity with laboratory and field methods. Catena. doi:10.1016/j.catena.2014.01.009 Barreiro, A., Fontúrbel, M.T., Lombao, A., Martín, C., Vega, J.A., Fernández, C., Carballas, T., Díaz-Raviña, M., Using phospholipid fatty acid and community level physiological profiling techniques to characterize soil microbial communities following an experimental fire and different stabilization treatments. Catena. doi:10.1016/j.catena.2014.07.011 Bodi, M., Martin, D.A., Santin, C., Balfour, V., Doerr, S.H., Pereira, P., Cerda, A., Mataix-Solera, J. (2014) Wildland fire ash: production, composition and eco-hydro-geomorphic effects. Earth-Science Reviews, 130, 103-127. Bodí, M.B., Doerr, S.H., Cerdà, A. and Mataix-Solera, J. (2012) Hydrological effects of a layer of vegetation ash on underlying wettable and water repellent soils. Geoderma, 191, 14-23. Burjachs, F., Expósito, I., Charcoal and pollen analysis: examples of Holocene fire dynamics in Mediterranean Iberian Peninsula. Catena. doi:10.1016/j.catena.2014.10.006 Burns, K., Gabet, E., The effective viscosity of slurries laden with vegetative ash. Catena. doi:10.1016/j.catena.2014.06.008 Cerdà, A. Doerr, S.H. (2008). The effect of ash and needle cover on surface runoff and erosion in the immediate post-fire period. Catena, 74 , 256-263. Dlapa, P., Bodí, M.B., Mataix-Solera, J., Cerdà, A., Doerr, S.H., Organic matter and wettability characteristics of wildfire ash from Mediterranean conifer forests. Catena. doi:10.1016/j.catena.2014.06.018 Dorta Almenar, I., Navarro Rivero, F.J., Arbelo, C.D., Rodríguez, A., Notario del Pino, J., The temporal distribution of water-soluble nutrients from high mountain soils following a wildfire within legume scrubland of Tenerife, Canary Islands, Spain. Catena. Escuday, M., Arancibia-Miranda, N., Pizarro, C., Antilén, M., Effect of ash from forest fires on leaching in volcanic soils. Catena. doi:10.1016/j.catena.2014.08.006 León, J., Echeverría, M.T., Marti, C., Badía, D., Can ash control infiltration rate after burning? An example in burned calcareous and gypseous soils in the Ebro Basin (NE Spain). Catena. doi:10.1016/j.catena.2014.05.024 Lombao, A., Barreiro, A., Carballas, T., Fontúrbel, M.T., Martín, C., Vega, J.A., Fernández, C., Díaz-Raviña, M., 2014. Changes in soil properties after a wildfire in Fragas do Eume Natural Park (Galicia, NW Spain). Catena. doi:10.1016/j.catena.2014.08.007 Pereira, P., Jordan, A., Cerda, A., Martin, D. (2014) Editorial: The role of ash in fire-affected ecosystems, Catena (In press) doi:10.1016/j.catena.2014.11.016 Pereira, P., Úbeda, X., Martin, D., Mataix-Solera, J., Cerdà, A., Burguet, M. (2014a) Wildfire effects on extractable elements in ash from a Pinus pinaster forest in Portugal, Hydrological Processes, 28, 3681-3690. Pereira, P., Ubeda, X., Mataix-Solera, J., Oliva, M., Novara, A. (2014) Short-term spatio-temporal spring grassland fire effects on soil colour,organic matter and water repellency in Lithuania, Solid Earth, 5, 209-225. Silva, V., Pereira, J.S., Campos, I., Keizer, J.J., Gonçalves, F., Abrantes, N., Toxicity assessment of aqueous extracts of ash from forest fires. Catena doi:10.1016/j.catena.2014.06.021

Contributions of microbial activity and ash deposition to post-fire nitrogen availability in a pine savanna

NASA Astrophysics Data System (ADS)

Ficken, Cari D.; Wright, Justin P.

2017-01-01

Many ecosystems experience drastic changes to soil nutrient availability associated with fire, but the magnitude and duration of these changes are highly variable among vegetation and fire types. In pyrogenic pine savannas across the southeastern United States, pulses of soil inorganic nitrogen (N) occur in tandem with ecosystem-scale nutrient losses from prescribed burns. Despite the importance of this management tool for restoring and maintaining fire-dependent plant communities, the contributions of different mechanisms underlying fire-associated changes to soil N availability remain unclear. Pulses of N availability following fire have been hypothesized to occur through (1) changes to microbial cycling rates and (2) direct ash deposition. Here, we document fire-associated changes to N availability across the growing season in a longleaf pine savanna in North Carolina. To differentiate between possible mechanisms driving soil N pulses, we measured net microbial cycling rates and changes to soil δ15N before and after a burn. Our findings refute both proposed mechanisms: we found no evidence for changes in microbial activity, and limited evidence that ash deposition could account for the increase in ammonium availability to more than 5-25 times background levels. Consequently, we propose a third mechanism to explain post-fire patterns of soil N availability, namely that (3) changes to plant sink strength may contribute to ephemeral increases in soil N availability, and encourage future studies to explicitly test this mechanism.

Monitoring post-fire recovery of shrublands in Mediterranean-type ecosystems using MODIS and TM/ETM+ data

NASA Astrophysics Data System (ADS)

Hope, Allen; Albers, Noah; Bart, Ryan

2010-05-01

Wildland fires in Mediterranean-Type Ecosystems (MTEs) are episodic events that dramatically alter land-cover conditions. Monitoring post-fire vegetation recovery is important for land management applications such as the scheduling of prescribed burns, post-fire resource management and soil erosion control. Full recovery of MTE shrublands may take many years and have a prolonged effect on water, energy and carbon fluxes in these ecosystems. Comparative studies of fynbos ecosystems in the Cape Floristic Region of South Africa (Western Cape Region) and chaparral ecosystems of California have demonstrated that there is a considerable degree of convergence in some aspects of post-fire vegetation regeneration and marked differences in other aspects. Since these MTEs have contrasting rainfall and soil nutrient conditions, an obvious question arises as to the similarity or dissimilarity in remotely sensed post-fire recovery pathways of vegetation stands in these two regions and the extent to which fire severity and drought impact the rate of vegetation recovery. Post-fire recovery pathways of chaparral and fynbos vegetation stands were characterized using the normalized difference vegetation index (NDVI) based on TM/ETM+ and MODIS (250 m) data. Procedures based on stands of unburned vegetation (control) were implemented to normalize the NDVI for variations associated with inter-annual differences in rainfall. Only vegetation stands that had not burned for 20 years were examined in this study to eliminate potential effects of variable fire histories on the recovery pathways. Post-fire recovery patterns of vegetation in both regions and across different vegetation types were found to be very similar. Post-fire stand age was the primary control over vegetation recovery and the NDVI returned to pre-fire values within seven to 10 years of the fires. Droughts were shown to cause slight interruptions in recovery rates while fire severity had no discernable effect. Intra-stand variability in the NDVI (pixel-scale) also returned to pre-fire values within the same time frame but increased with water stress associated with droughts. While these studies indicated that the NDVI of fynbos and chaparral stands recovered to pre-fire values within 10 years, it is recognized that other ecosystem characteristics may take considerably longer to recover. Despite the larger pixel size, MODIS data were found to be more suitable for monitoring vegetation post-fire recovery than TM/ETM+ data, requiring considerably less pre-processing and providing substantially more information regarding phenological characteristics of recovery pathways. Future studies will include consideration of fire history in the post-fire recovery characteristics of vegetation in these two MTEs.

Predicting hydrological and erosional risks in fire-affected watersheds: recent advances and research gaps

NASA Astrophysics Data System (ADS)

Nunes, João Pedro; Keizer, Jan Jacob

2017-04-01

Models can be invaluable tools to assess and manage the impacts of forest fires on hydrological and erosion processes. Immediately after fires, models can be used to identify priority areas for post-fire interventions or assess the risks of flooding and downstream contamination. In the long term, models can be used to evaluate the long-term implications of a fire regime for soil protection, surface water quality and potential management risks, or determine how changes to fire regimes, caused e.g. by climate change, can impact soil and water quality. However, several challenges make post-fire modelling particularly difficult: • Fires change vegetation cover and properties, such as by changing soil water repellency or by adding an ash layer over the soil; these processes, however are not described in currently used models, so that existing models need to be modified and tested. • Vegetation and soils recover with time since fire, changing important model parameters, so that the recovery processes themselves also need to be simulated, including the role of post-fire interventions. • During the window of vegetation and soil disturbance, particular weather conditions, such as the occurrence of severe droughts or extreme rainfall events, can have a large impact on the amount of runoff and erosion produced in burnt areas, so that models that smooth out these peak responses and rather simulate "long-term" average processes are less useful. • While existing models can simulate reasonable well slope-scale runoff generation and associated sediment losses and their catchment-scale routing, few models can accommodate the role of the ash layer or its transport by overland flow, in spite of its importance for soil fertility losses and downstream contamination. This presentation will provide an overview of the importance of post-fire hydrological and erosion modelling as well as of the challenges it faces and of recent efforts made to overcome these challenges. It will illustrate these challenges with two examples: probabilistic approaches to simulate the impact of different vegetation regrowth and post-fire climate combinations on runoff and erosion; and model developments for post-fire soil water repellency with different levels of complexity. It will also present an inventory of the current state-of-the-art and propose future research directions, both on post-fire models themselves and on their integration with other models in large-scale water resource assessment management.

Shifts in the abundance and community structure of soil ammonia oxidizers in a wet sclerophyll forest under long-term prescribed burning.

PubMed

Long, Xi-En; Chen, Chengrong; Xu, Zhihong; He, Ji-Zheng

2014-02-01

Fire shapes global biome distribution and promotes the terrestrial biogeochemical cycles. Ammonia-oxidizing bacteria (AOB) and archaea (AOA) play a vital role in the biogeochemical cycling of nitrogen (N). However, behaviors of AOB and AOA under long-term prescribed burning remain unclear. This study was to examine how fire affected the abundances and communities of soil AOB and AOA. A long-term repeated forest fire experiment with three burning treatments (never burnt, B0; biennially burnt, B2; and quadrennially burnt, B4) was used in this study. The abundances and community structure of soil AOB and AOA were determined using quantitative PCR, restriction fragment length polymorphism and clone library. More frequent fires (B2) increased the abundance of bacterium amoA gene, but tended to decrease archaeal amoA genes. Fire also modified the composition of AOA and AOB communities. Canonical correspondence analysis showed soil pH and dissolved organic C (DOC) strongly affected AOB genotypes, while nitrate-N and DOC shaped the AOA distribution. The increased abundance of bacterium amoA gene by fires may imply an important role of AOB in nitrification in fire-affected soils. The fire-induced shift in the community composition of AOB and AOA demonstrates that fire can disturb nutrient cycles. © 2013.

Data set on the effects of conifer control and slash burning on soil carbon, total N, organic matter and extractable micro-nutrients.

PubMed

Bates, Jonathan D; Davies, Kirk W

2017-10-01

Conifer control in sagebrush steppe of the western United States causes various levels of site disturbance influencing vegetation recovery and resource availability. The data set presented in this article include growing season availability of soil micronutrients and levels of total soil carbon, organic matter, and N spanning a six year period following western juniper ( Juniperus occidentalis spp. occidentalis ) reduction by mechanical cutting and prescribed fire of western juniper woodlands in southeast Oregon. These data can be useful to further evaluate the impacts of conifer woodland reduction to soil resources in sagebrush steppe plant communities.

Modelling soil sodium and potassium adsorption ratio (SPAR) in the immediate period after a grassland fire in Lithuania.

NASA Astrophysics Data System (ADS)

Pereira, Paulo; Cerda, Artemi; Misiūnė, Ieva

2015-04-01

The soil sodium and potassium adsorption ratio (SPAR) is an index that measures the amount of sodium and potassium adsorbed onto clay and organic matter surfaces, in relation to calcium and magnesium. Assess the potential of soil dispersion or flocculation, a process which has implication in soil hydraulic properties and erosion (Sarah, 2004). Depending on severity and the type of ash produced, fire can changes in the immediate period the soil nutrient status (Bodi et al. 2014). Ash releases onto soil surface a large amount of cations, due the high pH. Previous works showed that SPAR from ash slurries is higher than solutions produced from litter (Pereira et al., 2014a). Normally the spatial distribution of topsoil nutrients in the immediate period after the fire is very heterogeneous, due to the different impacts of fire. Thus it is important to identify the most accurate interpolation method in order to identify with better precision the impacts of fire on soil properties. The objective of this work is to test several interpolation methods. The study area is located in near Vilnius (Lithuania) at 54° 42' N, 25° 08 E, 158 masl. Four days after the fire it was designed a plot in a burned area with near Vilnius (Lithuania) at 54° 42' N, 25° 08 E, 158 masl. Twenty five samples were collected from the topsoil. The SPAR index was calculated according to the formula: (Na++K+)/(Ca2++Mg2+)1/2 (Sarah, 2004). Data followed the normal distribution, thus no transformation was required previous to data modelling. Several well know interpolation models were tested, as Inverse Distance to a Weight (IDW) with the power of 1, 2, 3 and 4, Radial Basis Functions (RBF), Inverse Multiquadratic (IMT), Multilog (MTG), Multiquadratic (MTQ), Natural Cubic Spline (NCS) and Thin Plate Spline (TPS) and Local Polynomial (LP) with the power of 1 and 2 and Ordinary Kriging. The best interpolator was the one which had the lowest Root Mean Square Error (RMSE) (Pereira et al., 2014b). The results showed that on average, SPAR index was 0.85, with a minimum of 0.18, a maximum of 1.55, a standard deviation of 0.38 and a coefficient of variation of 44.70%. No previous works were carried out on fire-affected soils, however comparing it to ash slurries obtained from previous works (Pereira et al., 2014a), the values were higher. Among all the interpolation methods tested, the most accurate was IDW 1 (RMSE=0.393), and the less precise NCS (RMSE=0.542). This shows that data distribution is highly variable in space, since IDW methods are better interpolators for data irregularly distributed. The high spatial variability distribution of SPAR is very likely to affect soil hydraulic properties and plant recuperation in the immediate period after the fire. More research is needed to identify the SPAR spatio-temporal impacts of fire on soil. Acknowledgments POSTFIRE (Soil quality, erosion control and plant cover recovery under different post-fire management scenarios, CGL2013-47862-C2-1-R), funded by the Spanish Ministry of Economy and Competitiveness; Fuegored; RECARE (Preventing and Remediating Degradation of Soils in Europe Through Land Care, FP7-ENV-2013-TWO STAGE), funded by the European Commission; and for the COST action ES1306 (Connecting European connectivity research). References Bodi, M., Martin, D.A., Santin, C., Balfour, V., Doerr, S.H., Pereira, P., Cerda, A., Mataix-Solera, J. (2014) Wildland fire ash: production, composition and eco-hyro-geomorphic effects. Earth-Science Reviews, 130, 103-127. Pereira, P., Úbeda, X., Martin, D., Mataix-Solera, J., Cerdà, A., Burguet, M. (2014a) Wildfire effects on extractable elements in ash from Pinus Pinaster forest in Portugal. Hydrological Processes, 28, 3681-3690. Pereira, P., Cerdà, A., Úbeda, X., Mataix-Solera, J. Arcenegui, V., Zavala, L. (2014) Modelling the impacts of wildfire on ash thickness in the immediate period after the fire. Land Degradation and Development. DOI: 10.1002/ldr.2195 Sarah, P. (2004) Soil sodium and potassium adsorption ratio along a Mediterranean-arid transect. Journal of Arid Environments, 59, 731-741.

Modelling the effect of wildfire on forested catchment water quality using the SWAT model

NASA Astrophysics Data System (ADS)

Yu, M.; Bishop, T.; van Ogtrop, F. F.; Bell, T.

2016-12-01

Wildfire removes the surface vegetation, releases ash, increase erosion and runoff, and therefore effects the hydrological cycle of a forested water catchment. It is important to understand chnage and how the catchment recovers. These processes are spatially sensitive and effected by interactions between fire severity and hillslope, soil type and surface vegetation conditions. Thus, a distributed hydrological modelling approach is required. In this study, the Soil and Water Analysis Tool (SWAT) is used to predict the effect of 2001/02 Sydney wild fire on catchment water quality. 10 years pre-fire data is used to create and calibrate the SWAT model. The calibrated model was then used to simulate the water quality for the 10 years post-fire period without fire effect. The simulated water quality data are compared with recorded water quality data provided by Sydney catchment authority. The mean change of flow, total suspended solid, total nitrate and total phosphate are compare on monthly, three month, six month and annual basis. Two control catchment and three burn catchment were analysed.

Wildfire as a hydrological and geomorphological agent

NASA Astrophysics Data System (ADS)

Shakesby, R. A.; Doerr, S. H.

2006-02-01

Wildfire can lead to considerable hydrological and geomorphological change, both directly by weathering bedrock surfaces and changing soil structure and properties, and indirectly through the effects of changes to the soil and vegetation on hydrological and geomorphological processes. This review summarizes current knowledge and identifies research gaps focusing particularly on the contribution of research from the Mediterranean Basin, Australia and South Africa over the last two decades or so to the state of knowledge mostly built on research carried out in the USA. Wildfire-induced weathering rates have been reported to be high relative to other weathering processes in fire-prone terrain, possibly as much as one or two magnitudes higher than frost action, with important implications for cosmogenic-isotope dating of the length of rock exposure. Wildfire impacts on soil properties have been a major focus of interest over the last two decades. Fire usually reduces soil aggregate stability and can induce, enhance or destroy soil water repellency depending on the temperature reached and its duration. These changes have implications for infiltration, overland flow and rainsplash detachment. A large proportion of publications concerned with fire impacts have focused on post-fire soil erosion by water, particularly at small scales. These have shown elevated, sometimes extremely large post-fire losses before geomorphological stability is re-established. Soil losses per unit area are generally negatively related to measurement scale reflecting increased opportunities for sediment storage at larger scales. Over the last 20 years, there has been much improvement in the understanding of the forms, causes and timing of debris flow and landslide activity on burnt terrain. Advances in previously largely unreported processes (e.g. bio-transfer of sediment and wind erosion) have also been made. Post-fire hydrological effects have generally also been studied at small rather than large scales, with soil water repellency effects on infiltration and overland flow being a particular focus. At catchment scales, post-fire accentuated peakflow has received more attention than changes in total flow, reflecting easier measurement and the greater hazard posed by the former. Post-fire changes to stream channels occur over both short and long terms with complex feedback mechanisms, though research to date has been limited. Research gaps identified include the need to: (1) develop a fire severity index relevant to soil changes rather than to degree of biomass destruction; (2) isolate the hydrological and geomorphological impacts of fire-induced soil water repellency changes from other important post-fire changes (e.g. litter and vegetation destruction); (3) improve knowledge of the hydrological and geomorphological impacts of wildfire in a wider range of fire-prone terrain types; (4) solve important problems in the determination and analysis of hillslope and catchment sediment yields including poor knowledge about soil losses other than at small spatial and short temporal scales, the lack of a clear measure of the degradational significance of post-fire soil losses, and confusion arising from errors in and lack of scale context for many quoted post-fire soil erosion rates; and (5) increase the research effort into past and potential future hydrological and geomorphological changes resulting from wildfire.

Lead particle size and its association with firing conditions and range maintenance: implications for treatment.

PubMed

Dermatas, Dimitris; Chrysochoou, Maria

2007-08-01

Six firing range soils were analyzed, representing different environments, firing conditions, and maintenance practices. The particle size distribution and lead (Pb) concentration in each soil fraction were determined for samples obtained from the backstop berms. The main factors that were found to influence Pb fragment size were the type of soil used to construct the berms and the type of weapon fired. The firing of high velocity weapons, i.e., rifles, onto highly angular soils induced significant fragmentation of the bullets and/or pulverization of the soil itself. This resulted in the accumulation of Pb in the finer soil fractions and the spread of Pb contamination beyond the vicinity of the backstop berm. Conversely, the use of clay as backstop and the use of low velocity pistols proved to be favorable for soil clean-up and range maintenance, since Pb was mainly present as large metallic fragments that can be recovered by a simple screening process. Other factors that played important roles in Pb particle size distribution were soil chemistry, firing distance, and maintenance practices, such as the use of water spray for dust suppression and deflectors prior to impact. Overall, coarse Pb particles provide much easier and more cost-effective maintenance, soil clean-up, and remediation via physical separation. Fine Pb particles release Pb more easily, pose an airborne Pb hazard, and require the application of stabilization/solidification treatment methods. Thus, to ensure sustainable firing range operations by means of cost-effective design, maintenance, and clean-up, especially when high velocity weapons are used, the above mentioned factors should be carefully considered.

Growing season soil moisture following restoration treatments of varying intensity in semi-arid ponderosa pine forests

NASA Astrophysics Data System (ADS)

O'Donnell, F. C.; Springer, A. E.; Sankey, T.; Masek Lopez, S.

2014-12-01

Forest restoration projects are being planned for large areas of overgrown semi-arid ponderosa pine forests of the Southwestern US. Restoration involves the thinning of smaller trees and prescribed or managed fire to reduce tree density, restore a more natural fire regime, and decrease the risk of catastrophic wildfire. The stated goals of these projects generally reduced plant water stress and improvements in hydrologic function. However, little is known about how to design restoration treatments to best meet these goals. As part of a larger project on snow cover, soil moisture, and groundwater recharge, we measured soil moisture, an indicator of plant water status, in four pairs of control and restored sites near Flagstaff, Arizona. The restoration strategies used at the sites range in both amount of open space created and degree of clustering of the remaining trees. We measured soil moisture using 30 cm vertical time domain reflectometry probes installed on 100 m transects at 5 m intervals so it would be possible to analyze the spatial pattern of soil moisture. Soil moisture was higher and more spatially variable in the restored sites than the control sites with differences in spatial pattern among the restoration types. Soil moisture monitoring will continue until the first snow fall, at which point measurements of snow depth and snow water equivalent will be made at the same locations.

Fire impact on soil-water repellency and functioning of semi-arid croplands and rangelands: Implications for prescribed burnings and wildfires

NASA Astrophysics Data System (ADS)

Stavi, Ilan; Barkai, Daniel; Knoll, Yaakov M.; Glion, Hiam Abu; Katra, Itzhak; Brook, Anna; Zaady, Eli

2017-03-01

An unintended fire outbreak during summer 2015 in the semi-arid Israeli Negev resulted in the burning of extensive croplands and rangelands. The rangelands have been managed over the long term for occasional grazing, while the croplands have been utilized for rainfed wheat cropping. Yet, during the studied year, the croplands were left fallow, allowing the growth of herbaceous vegetation, which was harvested and baled for hay before the fire outbreak. The study objectives were to investigate the impacts of fire, land-use, and soil depth on water-repellency and on the status and dynamics of some of the most important organic and mineral soil resources. Additionally, we aimed to assess the severity of this fire outbreak. The soil-water repellency was studied by measuring the soil's water drop penetration time (WDPT) and critical surface tension (CST). A significant effect of fire on soil hydrophobicity was recorded, with a slight increase in mean WDPT and a slight decrease in mean CST in the burnt sites than in the non-burnt sites. Yet, soil hydrophobicity in the burnt lands was rather moderate and remained within the water repellency's lowest class. A significant effect of land-use on the means of WDPT and CST was also recorded, being eleven-fold greater and 7% smaller, respectively, in the rangelands than in the croplands. This is consistent with the almost eightfold greater mean above-ground biomass recorded in the non-burnt rangelands than in the non-burnt post-harvest croplands, revealing the positive relations between available fuel load and soil-water repellency. The effect of soil depth was significant for CST but not for WDPT. Overall, the gathered data suggest that fire severity was low to moderate. Fire was also found to significantly affect the < 250 μm particle size fraction of the unconsolidated material cover, its mass being twofold to threefold greater in the non-burnt than in the burnt sites. Yet, soil organic carbon and ammonium-N were also studied, and generally showed higher values for the burnt lands. Overall, this study shows that the low- to moderate-fire severity only slightly increased the soil water repellency, and at the same time, increased on-site availability of some important soil resources. Nevertheless, it is acknowledged that such fires could impose risks to off-site air and water source quality. This study has implications for the assessment of geo-ecosystem functioning, as well as for the status and dynamics of soil resources following prescribed burnings or wildfires.

Mid-term and scaling effects of forest residue mulching on post-fire runoff and soil erosion.

PubMed

Prats, Sergio Alegre; Wagenbrenner, Joseph W; Martins, Martinho António Santos; Malvar, Maruxa Cortizo; Keizer, Jan Jacob

2016-12-15

Mulching is an effective post-fire soil erosion mitigation treatment. Experiments with forest residue mulch have demonstrated that it increased ground cover to 70% and reduced runoff and soil loss at small spatial scales and for short post-fire periods. However, no studies have systematically assessed the joint effects of scale, time since burning, and mulching on runoff, soil loss, and organic matter loss. The objective of this study was to evaluate the effects of scale and forest residue mulch using 0.25m 2 micro-plots and 100m 2 slope-scale plots in a burnt eucalypt plantation in central Portugal. We assessed the underlying processes involved in the post-fire hydrologic and erosive responses, particularly the effects of soil moisture and soil water repellency. Runoff amount in the micro-plots was more than ten-fold the runoff in the larger slope-scale plots in the first year and decreased to eight-fold in the third post-fire year. Soil losses in the micro-plots were initially about twice the values in the slope-scale plots and this ratio increased over time. The mulch greatly reduced the cumulative soil loss measured in the untreated slope-scale plots (616gm -2 ) by 91% during the five post-fire years. The implications are that applying forest residue mulch immediately after a wildfire can reduce soil losses at spatial scales of interest to land managers throughout the expected post-fire window of disturbance, and that mulching resulted in a substantial relative gain in soil organic matter. Copyright © 2016 Elsevier B.V. All rights reserved.

Relative influence of wildfire on soil properties and erosion processes in different Mediterranean environments in NE Spain.

PubMed

Pardini, Giovanni; Gispert, Maria; Dunjó, Gemma

2004-07-26

Abandonment of terraced soils and increased brushland cover has increased wildfire occurrence to almost an annual rate in the Cap de Creus Peninsula, NE Pyrenees Range, Province of Girona, Spain. A wildfire occurred in August 2000 and affected an area of 6760 ha of shrubs and cork trees, whereas still cultivated plots were only slightly affected. Five stations of erosion measurements, corresponding to five different environments (from present cultivation to late abandonment) were destroyed by the passage of fire, and were promptly replaced to allow to monitoring post-fire effects on soil erosion. Selected soil properties were determined monthly before the fire and during 6 months after the fire at a monthly rate. Runoff and sediment yield together with dissolved organic carbon (DOC) in runoff water and organic carbon losses in eroded sediments (EOC) were evaluated throughout 2000. The last stage of abandonment, stands of cork trees, had the highest soil stability. Nevertheless, evidence of unfavourable soil conditions was detected at the shrub stage, when Cistus monspeliensis cover was the dominant opportunistic plant. This stage was considered to be a critical threshold leading either to degradation or regeneration processes according to fire frequency. A drastic change in soil properties, erosion and nutrient depletion occurred after the fire in all the environments. Statistics enabled to state that environments differed significantly in main soil properties. By statistically comparing the measured variables between the environments before and after the fire, DOC was found to be the soil parameter showing the highest significance between environments. Absolute values of erosion were low with respect to other Mediterranean environments although the shallow nature of these soils might deserve special attention because of a comparatively higher risk of degradation. Copyright 2004 Elsevier B.V.

Soil water balance as affected by throughfall in gorse ( Ulex europaeus, L.) shrubland after burning

NASA Astrophysics Data System (ADS)

Soto, Benedicto; Diaz-Fierros, Francisco

1997-08-01

The role of fire in the hydrological behaviour of gorse shrub is studied from the point of view of its effects on vegetation cover and throughfall. In the first year after fire, throughfall represents about 88% of gross rainfall, whereas in unburnt areas it is 58%. Four years after fire, the throughfall coefficients are similar in burnt and unburnt plots (about 6096). The throughfall is not linearly related to vegetation cover because an increase in cover does not involve a proportional reduction in throughfall. The throughfall predicted by the two-parameter exponential model of Calder (1986, J. Hydrol., 88: 201-211) provides a good fit with the observed throughfall and the y value of the model reflects the evolution of throughfall rate. The soil moisture distribution is modified by fire owing to the increase of evaporation in the surface soil and the decrease of transpiration from deep soil layers. Nevertheless, the use of the old root system by sprouting vegetation leads to a soil water profile in which 20 months after the fire the soil water is similar in burnt and unburnt areas. Overall, soil moisture is higher in burnt plots than in unburnt plots. Surface runoff increases after a fire but does not entirely account for the increase in throughfall. Therefore the removal of vegetation cover in gorse scrub by fire mainly affects the subsurface water flows.

Post-fire comparisons of forest floor and soil carbon, nitrogen, and mercury pools with fire severity indices

Treesearch

Randy Kolka; Brian Sturtevant; Philip Townsend; Jessica Miesel; Peter Wolter; Shawn Fraver; Tom DeSutter

2014-01-01

Forest fires are important contributors of C, N, and Hg to the atmosphere. In the fall of 2011, a large wildfire occurred in northern Minnesota and we were able to quickly access the area to sample the forest floor and mineral soil for C, N, and Hg pools. When compared with unburned reference soils, the mean loss of C resulting from fire in the forest floor and the...

Soil charcoal from the plains to tundra in the Colorado Front Range

NASA Astrophysics Data System (ADS)

Sanford, R. L.; Licata, C.

2010-12-01

Throughout the forests of the central Rockies, soil charcoal from Holocene wildfires has been produced in response to wildland natural fire regimes. The extent and spatial distribution of soil charcoal production is poorly documented in this region, especially with regard to forests and shrublands at different elevations. Soil charcoal is a super-passive C pool derived from woody biomass that can be sequestered for millennia in forest soils. Recent research indicates that soil charcoal may promote enhanced soil fertility. Additionally, soil charcoal is an often overlooked component of soil C mass and flux. We hypothesize that differences in forest and shrubland fire regimes over the millennia have resulted in different soil charcoal amounts. Geospatial data were used to locate random sample plots in foothills shrublands (Cercocarpus montanus), and four forest types; ponderosa pine (Pinus ponderosa), Douglas-fir (Pseudotsuga menziesii), lodgepole pine (Pinus contorta) and spruce-fir (Picea engelmannii - Abies lasiocarpa). Sample plots were stratified to occur with the mid 200 m elevation band of each vegetation type with east aspect, and 10-30% slope. Soils were sampled widely at 0-10 cm depth and analyzed for total soil C and soil charcoal C via chemical digestion and dry combustion techniques. Overall, soil charcoal is four times more abundant in spruce-fir forests than in foothills shrublands (1.9 +/- 0.92 Mg C/ha versus 0.54 +/- 0.44 Mg C/ha). Soil charcoal is also abundant in lodgepole pine and ponderosa pine soils (1.4 +/- 1.02 Mg C/ha and 1.4 +/- 0.54 Mg C/ha respectively) but is less plentiful in Douglas-fir soils (1.0 +/- 0.67). Spruce-fir forests have the most above ground biomass, slower decomposition rates and a less frequent mean fire return interval than the other four forests, hence it makes sense that high per-fire rates of charcoal production would occur in the spruce-fir zone, given large amounts of surface fuels at the time of fire. In contrast, low amounts of coarse woody debris in ponderosa, lodgepole, and shrub communities would cause less charcoal to form, despite higher fire frequencies. The Douglas-fir soil charcoal seems anomalously low, but it may reflect a combination of low forest floor woody debris and low fire frequency. Foothills shrublands have the least biomass, comparatively rapid decomposition rates and a more frequent mean fire return interval. We propose that high biomass and slow turnover rates in the spruce-fir forests creates conditions for relatively higher net soil charcoal accumulation.

‘Natural background’ soil water repellency in conifer forests of the north-western USA: Its prediction and relationship to wildfire occurrence

NASA Astrophysics Data System (ADS)

Doerr, S. H.; Woods, S. W.; Martin, D. A.; Casimiro, M.

2009-06-01

SummarySoils under a wide range of vegetation types exhibit water repellency following the passage of a fire. This is viewed by many as one of the main causes for accelerated post-fire runoff and soil erosion and it has often been assumed that strong soil water repellency present after wildfire is fire-induced. However, high levels of repellency have also been reported under vegetation types not affected by fire, and the question arises to what degree the water repellency observed at burnt sites actually results from fire. This study aimed at determining 'natural background' water repellency in common coniferous forest types in the north-western USA. Mature or semi-mature coniferous forest sites ( n = 81), which showed no evidence of recent fires and had at least some needle cast cover, were sampled across six states. After careful removal of litter and duff at each site, soil water repellency was examined in situ at the mineral soil surface using the Water Drop Penetration Time (WDPT) method for three sub-sites, followed by collecting near-surface mineral soil layer samples (0-3 cm depth). Following air-drying, samples were further analyzed for repellency using WDPT and contact angle ( θsl) measurements. Amongst other variables examined were dominant tree type, ground vegetation, litter and duff layer depth, slope angle and aspect, elevation, geology, and soil texture, organic carbon content and pH. 'Natural background' water repellency (WDPT > 5 s) was detected in situ and on air-dry samples at 75% of all sites examined irrespective of dominant tree species ( Pinus ponderosa, Pinus contorta, Picea engelmanii and Pseudotsuga menziesii). These findings demonstrate that the soil water repellency commonly observed in these forest types following burning is not necessarily the result of recent fire but can instead be a natural characteristic. The notion of a low background water repellency being typical for long-unburnt conifer forest soils of the north-western USA is therefore incorrect. It follows that, where pre-fire water repellency levels are not known or highly variable, post-fire soil water repellency conditions are an unreliable indicator in classifying soil burn severity. The terrain and soil variables examined showed, overall, no convincing relationship with the repellency levels observed ( R2 < 0.15) except that repellency was limited in soils (i) developed over meta-sedimentary lithology and (ii) with clay contents >4%. This suggests that water repellency levels cannot be predicted with confidence from common terrain or soil variables.

'Natural background' soil water repellency in conifer forests of the north-western USA: Its prediction and relationship to wildfire occurrence

USGS Publications Warehouse

Doerr, S.H.; Woods, S.W.; Martin, D.A.; Casimiro, M.

2009-01-01

Soils under a wide range of vegetation types exhibit water repellency following the passage of a fire. This is viewed by many as one of the main causes for accelerated post-fire runoff and soil erosion and it has often been assumed that strong soil water repellency present after wildfire is fire-induced. However, high levels of repellency have also been reported under vegetation types not affected by fire, and the question arises to what degree the water repellency observed at burnt sites actually results from fire. This study aimed at determining 'natural background' water repellency in common coniferous forest types in the north-western USA. Mature or semi-mature coniferous forest sites (n = 81), which showed no evidence of recent fires and had at least some needle cast cover, were sampled across six states. After careful removal of litter and duff at each site, soil water repellency was examined in situ at the mineral soil surface using the Water Drop Penetration Time (WDPT) method for three sub-sites, followed by collecting near-surface mineral soil layer samples (0-3 cm depth). Following air-drying, samples were further analyzed for repellency using WDPT and contact angle (??sl) measurements. Amongst other variables examined were dominant tree type, ground vegetation, litter and duff layer depth, slope angle and aspect, elevation, geology, and soil texture, organic carbon content and pH. 'Natural background' water repellency (WDPT > 5 s) was detected in situ and on air-dry samples at 75% of all sites examined irrespective of dominant tree species (Pinus ponderosa, Pinus contorta, Picea engelmanii and Pseudotsuga menziesii). These findings demonstrate that the soil water repellency commonly observed in these forest types following burning is not necessarily the result of recent fire but can instead be a natural characteristic. The notion of a low background water repellency being typical for long-unburnt conifer forest soils of the north-western USA is therefore incorrect. It follows that, where pre-fire water repellency levels are not known or highly variable, post-fire soil water repellency conditions are an unreliable indicator in classifying soil burn severity. The terrain and soil variables examined showed, overall, no convincing relationship with the repellency levels observed (R2 < 0.15) except that repellency was limited in soils (i) developed over meta-sedimentary lithology and (ii) with clay contents >4%. This suggests that water repellency levels cannot be predicted with confidence from common terrain or soil variables. ?? 2009 Elsevier B.V.

Fire frequency drives decadal changes in soil carbon and nitrogen and ecosystem productivity

NASA Astrophysics Data System (ADS)

Pellegrini, Adam F. A.; Ahlström, Anders; Hobbie, Sarah E.; Reich, Peter B.; Nieradzik, Lars P.; Staver, A. Carla; Scharenbroch, Bryant C.; Jumpponen, Ari; Anderegg, William R. L.; Randerson, James T.; Jackson, Robert B.

2018-01-01

Fire frequency is changing globally and is projected to affect the global carbon cycle and climate. However, uncertainty about how ecosystems respond to decadal changes in fire frequency makes it difficult to predict the effects of altered fire regimes on the carbon cycle; for instance, we do not fully understand the long-term effects of fire on soil carbon and nutrient storage, or whether fire-driven nutrient losses limit plant productivity. Here we analyse data from 48 sites in savanna grasslands, broadleaf forests and needleleaf forests spanning up to 65 years, during which time the frequency of fires was altered at each site. We find that frequently burned plots experienced a decline in surface soil carbon and nitrogen that was non-saturating through time, having 36 per cent (±13 per cent) less carbon and 38 per cent (±16 per cent) less nitrogen after 64 years than plots that were protected from fire. Fire-driven carbon and nitrogen losses were substantial in savanna grasslands and broadleaf forests, but not in temperate and boreal needleleaf forests. We also observe comparable soil carbon and nitrogen losses in an independent field dataset and in dynamic model simulations of global vegetation. The model study predicts that the long-term losses of soil nitrogen that result from more frequent burning may in turn decrease the carbon that is sequestered by net primary productivity by about 20 per cent of the total carbon that is emitted from burning biomass over the same period. Furthermore, we estimate that the effects of changes in fire frequency on ecosystem carbon storage may be 30 per cent too low if they do not include multidecadal changes in soil carbon, especially in drier savanna grasslands. Future changes in fire frequency may shift ecosystem carbon storage by changing soil carbon pools and nitrogen limitations on plant growth, altering the carbon sink capacity of frequently burning savanna grasslands and broadleaf forests.

Fire frequency drives decadal changes in soil carbon and nitrogen and ecosystem productivity.

PubMed

Pellegrini, Adam F A; Ahlström, Anders; Hobbie, Sarah E; Reich, Peter B; Nieradzik, Lars P; Staver, A Carla; Scharenbroch, Bryant C; Jumpponen, Ari; Anderegg, William R L; Randerson, James T; Jackson, Robert B

2018-01-11

Fire frequency is changing globally and is projected to affect the global carbon cycle and climate. However, uncertainty about how ecosystems respond to decadal changes in fire frequency makes it difficult to predict the effects of altered fire regimes on the carbon cycle; for instance, we do not fully understand the long-term effects of fire on soil carbon and nutrient storage, or whether fire-driven nutrient losses limit plant productivity. Here we analyse data from 48 sites in savanna grasslands, broadleaf forests and needleleaf forests spanning up to 65 years, during which time the frequency of fires was altered at each site. We find that frequently burned plots experienced a decline in surface soil carbon and nitrogen that was non-saturating through time, having 36 per cent (±13 per cent) less carbon and 38 per cent (±16 per cent) less nitrogen after 64 years than plots that were protected from fire. Fire-driven carbon and nitrogen losses were substantial in savanna grasslands and broadleaf forests, but not in temperate and boreal needleleaf forests. We also observe comparable soil carbon and nitrogen losses in an independent field dataset and in dynamic model simulations of global vegetation. The model study predicts that the long-term losses of soil nitrogen that result from more frequent burning may in turn decrease the carbon that is sequestered by net primary productivity by about 20 per cent of the total carbon that is emitted from burning biomass over the same period. Furthermore, we estimate that the effects of changes in fire frequency on ecosystem carbon storage may be 30 per cent too low if they do not include multidecadal changes in soil carbon, especially in drier savanna grasslands. Future changes in fire frequency may shift ecosystem carbon storage by changing soil carbon pools and nitrogen limitations on plant growth, altering the carbon sink capacity of frequently burning savanna grasslands and broadleaf forests.

Plant Community and Soil Environment Response to Summer Fire in the Northern Great Plains

USDA-ARS?s Scientific Manuscript database

Fire is a keystone process in many ecosystems, especially grasslands. However, documentation of plant community and soil environment responses to fire is limited for semiarid grasslands relative to that for mesic grasslands. Replicated summer fire research is lacking, but much needed because summe...

Impact of the extreme 2009 wildfire Victoria the wettability of naturally highly water repellent soils

NASA Astrophysics Data System (ADS)

Doerr, Stefan H.; Shakesby, Richard A.; Sheridan, Gary J.; Lane, Patrick Nj; Smith, Hugh G.; Bell, Tina; Blake, William H.

2010-05-01

The recent catastrophic wildfires near Melbourne, which peaked on Feb. 7 2009, burned ca 400,000 ha and caused the tragic loss of 173 people. They occurred during unprecedented extreme fire weather where dry northerly winds gusting up to 100 km/h coincided with the highest temperatures ever recorded in this region. These conditions, combined with the very high biomass of mature eucalypt forests, very low fuel moisture conditions and steep slopes, generated extreme burning conditions. A rapid response project was launched under the NERC Urgency Scheme aimed at determining the effects of this extreme event on soil properties. Three replicate sites each were sampled for extremely high burn severity, high burn severity and unburnt control terrain, within mature mixed-species eucalypt forests near Marysville in April 2009. Ash and surface soil (0-2.5 cm and 2.5-5 cm) were collected at 20 sample grid points at each site. Here we report on outcomes from Water Drop Penetration Time (WDPT) tests carried out on soil samples to determine the impact of this extreme event on the wettability of a naturally highly water repellent soil. Field assessment suggested that the impact of this extreme wildfire on the soil was less than might be supposed given the extreme burn severity (indicated by the complete elimination of the ground vegetation). This was confirmed by the laboratory results. No major difference in WDPT was detected between (i) burned and control samples, and (ii) between surface and subsurface WDPT patterns, indicating that soil temperatures in the top 0-2.5 cm did not exceed ~200° C. Seedling germination in burned soil was reduced by at least 2/3 compared to the control samples, however, this reduction is indicative an only modest heat input into the soil. The limited heat input into the soil stands in stark contrast to the extreme burn severity (based on vegetation destruction parameters). We speculate that limited soil heating resulted perhaps from the unusually fast-moving fire front and the resultant short fire residence time during this event. Thick ash layers were present at the time of sampling despite some significant earlier pre-sampling rainfall events. This suggests that the wettable ash (up to 15 cm thick) was able to store substantial amounts of water, which would otherwise have formed overland flow moving over the highly water repellent underlying mineral soil. Once this hydrological ‘sponge' is removed, the lack of ground cover is expected to lead to the underlying soil being susceptible to erosion until the ground cover becomes re-established. This ‘erosion window‘ is likely to be relatively brief over much of the burnt area as the vegetation is already showing a comparatively rapid regrowth response. This is supported by initial results from laboratory germination experiments, which showed seedling emergence from even the most severely burnt sites. The factors contributing to the fire impacts determined here are explored in conjunction with predictions for future burn severity under a changing climate. The soil samples collected represent a reference soil sample collection, which are available to the scientific community for further investigation.

Quantifying soil carbon loss and uncertainty from a peatland wildfire using multi-temporal LiDAR

USGS Publications Warehouse

Reddy, Ashwan D.; Hawbaker, Todd J.; Wurster, F.; Zhu, Zhiliang; Ward, S.; Newcomb, Doug; Murray, R.

2015-01-01

Peatlands are a major reservoir of global soil carbon, yet account for just 3% of global land cover. Human impacts like draining can hinder the ability of peatlands to sequester carbon and expose their soils to fire under dry conditions. Estimating soil carbon loss from peat fires can be challenging due to uncertainty about pre-fire surface elevations. This study uses multi-temporal LiDAR to obtain pre- and post-fire elevations and estimate soil carbon loss caused by the 2011 Lateral West fire in the Great Dismal Swamp National Wildlife Refuge, VA, USA. We also determine how LiDAR elevation error affects uncertainty in our carbon loss estimate by randomly perturbing the LiDAR point elevations and recalculating elevation change and carbon loss, iterating this process 1000 times. We calculated a total loss using LiDAR of 1.10 Tg C across the 25 km2 burned area. The fire burned an average of 47 cm deep, equivalent to 44 kg C/m2, a value larger than the 1997 Indonesian peat fires (29 kg C/m2). Carbon loss via the First-Order Fire Effects Model (FOFEM) was estimated to be 0.06 Tg C. Propagating the LiDAR elevation error to the carbon loss estimates, we calculated a standard deviation of 0.00009 Tg C, equivalent to 0.008% of total carbon loss. We conclude that LiDAR elevation error is not a significant contributor to uncertainty in soil carbon loss under severe fire conditions with substantial peat consumption. However, uncertainties may be more substantial when soil elevation loss is of a similar or smaller magnitude than the reported LiDAR error.

Changes in soil respiration after thinning activities in dense Aleppo pine forests

NASA Astrophysics Data System (ADS)

Llovet, Joan; Alonso, Macià; Cerdà, Artemi

2015-04-01

Forest fires are a widespread perturbation in Mediterranean areas, and they have tended to increase during the last decades (Pausas, 2004; Moreno et al, 1998). Aleppo pine (Pinus halepensis Mill) is dominant specie in some forest landscapes of western Mediterranean Basin, due to its capacity to colonize abandoned fields, and also due to afforestation practices mainly performed during the 20th century (Ruiz Navarro et al., 2009). Aleppo pine tends to die as consequence of forest fires, although it is able to disperse a high quantity of seeds which easily germinates. These dispersion and germination can result in dense forests with high inter and intra-specific competition, low diversity, low growth, and high fuel accumulation, increasing the risk of new forest fires. These forests of high density present ecological problems and management difficulties that require preventive treatments. Thinning treatments are common in these types of communities, but the management has to be oriented towards strengthening their functions. In the context of global change, better understandings of the implications of forest management practices in the carbon cycle are necessary. The objective of this study was to examine the evolution of seasonal soil respiration after treatment of selective thinning in dense Aleppo pine forests. The study area covers three localities placed in the Valencian Community (E Spain) affected by a forest fire in 1994. Thinning activities were done 16 years after the fire, reducing pine density from around 100,000 individuals per hectare to around 900 individuals per hectare. Soil respiration was measured in situ with a portable soil respiration instrument (LI-6400, LiCor, Lincoln, NB, USA) fitted with a soil respiration chamber (6400-09, LiCor, Lincoln, NB, USA). We installed 12 plots per treatment (control and thinned) and locality, being a total of 72 plots. We carried out 13 measurements covering a period of one year. We also estimated other related variables (i.e. soil characteristics, potential soil heterotrophic respiration, plant biomass surrounding each plot, soil temperature, and soil moisture). Main results showed a seasonal variation of soil respiration as related by other authors (i.e. Almagro et al., 2009), being soil respiration restricted by drying during summer, and by low temperatures during winter. On the other hand, thinning significantly diminished soil respiration, its decrease was around 33% (from 5.3 micromole CO2 m-2 second-1, to 3.6 micromole CO2 m-2 second-1). Our results suggest that autotrophic respiration could be highly responsible of this decrease: we found significant and positive relationships between soil respiration and vegetation surrounding plots, and we did not find differences in potential soil heterotrophic respiration between treatments. Acknowledgements We thanks the financial support of the RESILIEN project funded by the Spanish Government, Ministerio de Ciencia e Innovación CGL2011-30515-C02-02. The RECARE project is funded by the European Commission FP7 program, ENV.2013.6.2-4 "Sustainable land care in Europe". References Almagro, M., López, J., Querejeta, J. I., Martínez Mena, M. 2009. Temperature dependence of soil CO2 efflux is strongly modulated by seasonal patterns of moisture availability in a Meditarranean ecosystem. Soil Biology and Biochemistry, 41. 594-605 Moreno, J.M., Vázquez, A., Vélez, R. 1998. Recent history of forest fires in Spain. In: Moreno, J. M. (ed). Large Fires. Backhuys Publishers, Leiden, The Netherlands, pp. 159-185. Pausas, J. G., Ribeiro, E., Vallejo, V. R. 2004. Post-fire regeneration variability of Pinus halepensis in the eastern Iberian Peninsula. Forest Ecology and Management, 203. 251-259. Ruiz Navarro, A., Barberá, G. G., Navarro Cano, J. A., Albaladejo, J., Castillo, V. M. 2009. Soil dynamics in Pinus halepensis reforestation: Effect of microenvironment and previous land use. Geoderma, 153. 353-361.

Interactive effects of wildfire and permafrost on microbial communities and soil processes in an Alaskan black spruce forest

USGS Publications Warehouse

Waldrop, M.P.; Harden, J.W.

2008-01-01

Boreal forests contain significant quantities of soil carbon that may be oxidized to CO2 given future increases in climate warming and wildfire behavior. At the ecosystem scale, decomposition and heterotrophic respiration are strongly controlled by temperature and moisture, but we questioned whether changes in microbial biomass, activity, or community structure induced by fire might also affect these processes. We particularly wanted to understand whether postfire reductions in microbial biomass could affect rates of decomposition. Additionally, we compared the short-term effects of wildfire to the long-term effects of climate warming and permafrost decline. We compared soil microbial communities between control and recently burned soils that were located in areas with and without permafrost near Delta Junction, AK. In addition to soil physical variables, we quantified changes in microbial biomass, fungal biomass, fungal community composition, and C cycling processes (phenol oxidase enzyme activity, lignin decomposition, and microbial respiration). Five years following fire, organic surface horizons had lower microbial biomass, fungal biomass, and dissolved organic carbon (DOC) concentrations compared with control soils. Reductions in soil fungi were associated with reductions in phenol oxidase activity and lignin decomposition. Effects of wildfire on microbial biomass and activity in the mineral soil were minor. Microbial community composition was affected by wildfire, but the effect was greater in nonpermafrost soils. Although the presence of permafrost increased soil moisture contents, effects on microbial biomass and activity were limited to mineral soils that showed lower fungal biomass but higher activity compared with soils without permafrost. Fungal abundance and moisture were strong predictors of phenol oxidase enzyme activity in soil. Phenol oxidase enzyme activity, in turn, was linearly related to both 13C lignin decomposition and microbial respiration in incubation studies. Taken together, these results indicate that reductions in fungal biomass in postfire soils and lower soil moisture in nonpermafrost soils reduced the potential of soil heterotrophs to decompose soil carbon. Although in the field increased rates of microbial respiration can be observed in postfire soils due to warmer soil conditions, reductions in fungal biomass and activity may limit rates of decomposition. ?? 2008 The Authors Journal compilation ?? 2008 Blackwell Publishing.

Annual fire and mowing alter biomass, depth distribution, and C and N content of roots in soil in tallgrass prairie

Treesearch

D.J. Kitchen; J.M. Blair; M.A. Callaham

2009-01-01

Management practices, such as fire andmowing, can affect the distribution and quality of roots and soil C and N in grasslands. We examined long-term (13 years) effects of annual fire and mowing on fine (<2 mm) roots and soil C and N content in a native tallgrass prairie at Konza Prairie Biological Station in northeastern Kansas, USA. Using 90 cm deep soil cores...

Assessment of boreal forest historical C dynamics in the Yukon River Basin: relative roles of warming and fire regime change.

PubMed

Yuan, F M; Yi, S H; McGuire, A D; Johnson, K D; Liang, J; Harden, J W; Kasischke, E S; Kurz, W A

2012-12-01

Carbon (C) dynamics of boreal forest ecosystems have substantial implications for efforts to mitigate the rise of atmospheric CO2 and may be substantially influenced by warming and changing wildfire regimes. In this study we applied a large-scale ecosystem model that included dynamics of organic soil horizons and soil organic matter characteristics of multiple pools to assess forest C stock changes of the Yukon River Basin (YRB) in Alaska, USA, and Canada from 1960 through 2006, a period characterized by substantial climate warming and increases in wildfire. The model was calibrated for major forests with data from long-term research sites and evaluated using a forest inventory database. The regional assessment indicates that forest vegetation C storage increased by 46 Tg C, but that total soil C storage did not change appreciably during this period. However, further analysis suggests that C has been continuously lost from the mineral soil horizon since warming began in the 1970s, but has increased in the amorphous organic soil horizon. Based on a factorial experiment, soil C stocks would have increased by 158 Tg C if the YRB had not undergone warming and changes in fire regime. The analysis also identified that warming and changes in fire regime were approximately equivalent in their effects on soil C storage, and interactions between these two suggests that the loss of organic horizon thickness associated with increases in wildfire made deeper soil C stocks more vulnerable to loss via decomposition. Subbasin analyses indicate that C stock changes were primarily sensitive to the fraction of burned forest area within each subbasin and that boreal forest ecosystems in the YRB are currently transitioning from being sinks to sources at -0.7% annual area burned. We conclude that it is important for international mitigation efforts focused on controlling atmospheric CO2 to consider how climate warming and changes in fire regime may concurrently affect the CO2 sink strength of boreal forests. It is also important for large-scale biogeochemical and earth system models to include organic soil dynamics in applications to assess regional C dynamics of boreal forests responding to warming and changes in fire regime.

Assessment of boreal forest historical C dynamics in Yukon River Basin: relative roles of warming and fire regime change

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yuan, Fengming; Yi, Shuhua; McGuire, A. David

2012-01-01

Carbon (C) dynamics of boreal forest ecosystems have substantial implications for efforts to mitigate the rise of atmospheric CO2 and may be substantially influenced by warming and changing wildfire regimes. In this study we applied a large-scale ecosystem model that included dynamics of organic soil horizons and soil organic matter characteristics of multiple pools to assess forest C stock changes of the Yukon River Basin (YRB) in Alaska, USA, and Canada from 1960 through 2006, a period characterized by substantial climate warming and increases in wildfire. The model was calibrated for major forests with data from long-term research sites andmore » evaluated using a forest inventory database. The regional assessment indicates that forest vegetation C storage increased by 46 Tg C, but that total soil C storage did not change appreciably during this period. However, further analysis suggests that C has been continuously lost from the mineral soil horizon since warming began in the 1970s, but has increased in the amorphous organic soil horizon. Based on a factorial experiment, soil C stocks would have increased by 158 Tg C if the YRB had not undergone warming and changes in fire regime. The analysis also identified that warming and changes in fire regime were approximately equivalent in their effects on soil C storage, and interactions between these two suggests that the loss of organic horizon thickness associated with increases in wildfire made deeper soil C stocks more vulnerable to loss via decomposition. Subbasin analyses indicate that C stock changes were primarily sensitive to the fraction of burned forest area within each subbasin and that boreal forest ecosystems in the YRB are currently transitioning from being sinks to sources at ;0.7% annual area burned. We conclude that it is important for international mitigation efforts focused on controlling atmospheric CO2 to consider how climate warming and changes in fire regime may concurrently affect the CO2 sink strength of boreal forests. It is also important for large-scale biogeochemical and earth system models to include organic soil dynamics in applications to assess regional C dynamics of boreal forests responding to warming and changes in fire regime.« less

Assessment of boreal forest historical C dynamics in the Yukon River Basin: relative roles of warming and fire regime change

USGS Publications Warehouse

Yuan, F.M.; Yi, S.H.; McGuire, A.D.; Johnson, K.D.; Liang, J.; Harden, J.W.; Kasischke, E.S.; Kurz, W.A.

2012-01-01

Carbon (C) dynamics of boreal forest ecosystems have substantial implications for efforts to mitigate the rise of atmospheric CO2 and may be substantially influenced by warming and changing wildfire regimes. In this study we applied a large-scale ecosystem model that included dynamics of organic soil horizons and soil organic matter characteristics of multiple pools to assess forest C stock changes of the Yukon River Basin (YRB) in Alaska, USA, and Canada from 1960 through 2006, a period characterized by substantial climate warming and increases in wildfire. The model was calibrated for major forests with data from long-term research sites and evaluated using a forest inventory database. The regional assessment indicates that forest vegetation C storage increased by 46 Tg C, but that total soil C storage did not change appreciably during this period. However, further analysis suggests that C has been continuously lost from the mineral soil horizon since warming began in the 1970s, but has increased in the amorphous organic soil horizon. Based on a factorial experiment, soil C stocks would have increased by 158 Tg C if the YRB had not undergone warming and changes in fire regime. The analysis also identified that warming and changes in fire regime were approximately equivalent in their effects on soil C storage, and interactions between these two suggests that the loss of organic horizon thickness associated with increases in wildfire made deeper soil C stocks more vulnerable to loss via decomposition. Subbasin analyses indicate that C stock changes were primarily sensitive to the fraction of burned forest area within each subbasin and that boreal forest ecosystems in the YRB are currently transitioning from being sinks to sources at ∼0.7% annual area burned. We conclude that it is important for international mitigation efforts focused on controlling atmospheric CO2 to consider how climate warming and changes in fire regime may concurrently affect the CO2 sink strength of boreal forests. It is also important for large-scale biogeochemical and earth system models to include organic soil dynamics in applications to assess regional C dynamics of boreal forests responding to warming and changes in fire regime.

Soil shapes community structure through fire.

PubMed

Ojeda, Fernando; Pausas, Juli G; Verdú, Miguel

2010-07-01

Recurrent wildfires constitute a major selecting force in shaping the structure of plant communities. At the regional scale, fire favours phenotypic and phylogenetic clustering in Mediterranean woody plant communities. Nevertheless, the incidence of fire within a fire-prone region may present strong variations at the local, landscape scale. This study tests the prediction that woody communities on acid, nutrient-poor soils should exhibit more pronounced phenotypic and phylogenetic clustering patterns than woody communities on fertile soils, as a consequence of their higher flammability and, hence, presumably higher propensity to recurrent fire. Results confirm the predictions and show that habitat filtering driven by fire may be detected even in local communities from an already fire-filtered regional flora. They also provide a new perspective from which to consider a preponderant role of fire as a key evolutionary force in acid, infertile Mediterranean heathlands.

Hyperspectral remote sensing of postfire soil properties

Treesearch

Sarah A. Lewis; Peter R. Robichaud; William J. Elliot; Bruce E. Frazier; Joan Q. Wu

2004-01-01

Forest fires may induce changes in soil organic properties that often lead to water repellent conditions within the soil profile that decrease soil infiltration capacity. The remote detection of water repellent soils after forest fires would lead to quicker and more accurate assessment of erosion potential. An airborne hyperspectral image was acquired over the Hayman...

Fire effects on ponderosa pine soils and their management implications

Treesearch

W.W. Covington; S.S. Sackett

1990-01-01

Fire in southwestern ponderosa pine induces changes in soil properties including decreasing the amount of nutrients stored in fuels (forest floor, woody litter, and understory vegetation) increasing the amount of nutrients on the soil surface (the "ashbed effect"), and increasing the inorganic nitrogen and moisture content in the mineral soil. Soil...

Prescribed Fire Effects on Runoff, Erosion, and Soil Water Repellency on Steeply-Sloped Sagebrush Rangeland over a Five Year Period

NASA Astrophysics Data System (ADS)

Williams, C. J.; Pierson, F. B.; Al-Hamdan, O. Z.

2014-12-01

Fire is an inherent component of sagebrush steppe rangelands in western North America and can dramatically affect runoff and erosion processes. Post-fire flooding and erosion events pose substantial threats to proximal resources, property, and human life. Yet, prescribed fire can serve as a tool to manage vegetation and fuels on sagebrush rangelands and to reduce the potential for large catastrophic fires and mass erosion events. The impact of burning on event hydrologic and erosion responses is strongly related to the degree to which burning alters vegetation, ground cover, and surface soils and the intensity and duration of precipitation. Fire impacts on hydrologic and erosion response may be intensified or reduced by inherent site characteristics such as topography and soil properties. Parameterization of these diverse conditions in predictive tools is often limited by a lack of data and/or understanding for the domain of interest. Furthermore, hydrologic and erosion functioning change as vegetation and ground cover recover in the years following burning and few studies track these changes over time. In this study, we evaluated the impacts of prescribed fire on vegetation, ground cover, soil water repellency, and hydrologic and erosion responses 1, 2, and 5 yr following burning of a mountain big sagebrush community on steep hillslopes with fine-textured soils. The study site is within the Reynolds Creek Experimental Watershed, southwestern Idaho, USA. Vegetation, ground cover, and soil properties were measured over plot scales of 0.5 m2 to 9 m2. Rainfall simulations (0.5 m2) were used to assess the impacts of fire on soil water repellency, infiltration, runoff generation, and splash-sheet erosion. Overland flow experiments (9 m2) were used to assess the effects of fire-reduced ground cover on concentrated-flow runoff and erosion processes. The study results provide insight regarding fire impacts on runoff, erosion, and soil water repellency in the immediate and short-term post-fire recovery years for steeply-sloped sagebrush sites with fine-textured soils. The study results also serve to inform development and enhancement of the Rangeland Hydrology and Erosion Model for predicting runoff and erosion responses from disturbed and undisturbed sagebrush rangelands.

Advancing investigation and physical modeling of first-order fire effects on soils

Treesearch

William J. Massman; John M. Frank; Sacha J. Mooney

2010-01-01

Heating soil during intense wildland fires or slash-pile burns can alter the soil irreversibly, resulting in many significant long-term biological, chemical, physical, and hydrological effects. To better understand these long-term effects, it is necessary to improve modeling capability and prediction of the more immediate, or first-order, effects that fire can have on...

Prescribed fire, soil inorganic nitrogen dynamics, and plant responses in a semiarid grassland

Treesearch

David J. Augustine; Paul Brewer; Dana M. Blumenthal; Justin D. Derner; Joseph C. von Fischer

2014-01-01

In arid and semiarid ecosystems, fire can potentially affect ecosystem dynamics through changes in soil moisture, temperature, and nitrogen cycling, as well as through direct effects on plant meristem mortality. We examined effects of annual and triennial prescribed fires conducted in early spring on soil moisture, temperature, and N, plant growth, and plant N content...

Changes in marsh soils for six months after a fire

NASA Technical Reports Server (NTRS)

Schmalzer, Paul A.; Hinkle, C. R.; Koller, Albert M., Jr.

1991-01-01

An examination is conducted of changes in soil-nutrient levels in marsh systems after a fire, in conjunction with studies of particulates and gases generated by such biomass combustion. Attention is given to data covering six months after the fire. It is noted that changes in soil property occur at different times after the fire, and persist for different intervals; this implies a need for long-term postfire observations. The marshes studied were representative of a variety of graminoid wetlands in the southeastern U.S. which periodically burn either naturally or upon prescription. Nitrogen transformations in flooded soils differ from those in well-drained ones.

Monitoring Changes in Soil Quality from Post-fire Logging in the Inland Northwest

Treesearch

Deborah Page-Dumroese; Martin Jurgensen; Ann Abbott; Tom Rice; Joanne Tirocke; Sue Farley; Sharon DeHart

2006-01-01

The wildland fires of 2000, 2002, and 2003 created many opportunities to conduct post-fire logging operations in the Inland Northwest. Relatively little information is available on the impact of post-fire logging on long-term soil productivity or on the best method for monitoring these changes. We present a USDA Forest Service Northern Region study of post-fire logged...

Pyro-eco-hydrologic feedbacks and catchment co-evolution in fire-prone forested uplands

NASA Astrophysics Data System (ADS)

Sheridan, Gary; Inbar, Assaf; Lane, Patrick; Nyman, Petter

2017-04-01

The south east Australian forested uplands are characterized by complex and inter-correlated spatial patterns in standing biomass, soil depth/quality, and fire regimes, even within areas with similar rainfall, geology and catenary position. These system properties have traditionally been investigated independently, however recent research in the areas of post fire hydrology and erosion, and new insights into forest structure, fuel moisture, and flammability, suggest the presence of critical co-evolutionary feedbacks between fire, soils and vegetation that may explain the observed system states. To test this hypothesis we started with a published ecohydrologic model, modifying and extending the algorithms to capture feedbacks between hyrology and fire, and between fire, vegetation and soil production and erosion. The model was parameterized and calibrated with new data from instrumented forested hillslopes across energy and rainfall gradients generated by selecting sites with a range of aspect (energy) and elevation (rainall). The calibrated model was able to reasonably replicate the observed patterns of standing biomass, water balance, fire interval, and soil depth. The catchment co-evolution/feedback modelling approach to understanding patterns of vegetation, soils and fire regimes provides a promising new paradigm for predicting the response of forested se Australian catchments to declining rainfall and increasing temperatures under climate change.

Monitoring Soil Erosion of a Burn Site in the Central Basin and Range Ecoregion: Final Report on Measurements at the Gleason Fire Site, Nevada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, Julianne; Etyemezian, Vicken; Shillito, Rose

The increase in wildfires in arid and semi-arid parts of Nevada and elsewhere in the southwestern United States has implications for post-closure management and long-term stewardship for Soil Corrective Action Units (CAUs) on the Nevada National Security Site (NNSS) for which the Nevada Field Office of the United States Department of Energy, National Nuclear Security Administration has responsibility. For many CAUs and Corrective Action Sites, where closure-in-place alternatives are now being implemented or considered, there is a chance that these sites could burn over at some time while they still pose a risk to the environment or human health, givenmore » the long half lives of some of the radionuclide contaminants. This study was initiated to examine the effects and duration of wildfire on wind and water erodibility on sites analogous to those that exist on the NNSS. The data analyzed herein were gathered at the prescribed Gleason Fire site near Ely, Nevada, a site comparable to the northern portion of the NNSS. Quantification of wind erosion was conducted with a Portable In-Situ Wind ERosion Lab (PI-SWERL) on unburned soils, and on interspace and plant understory soils within the burned area. The PI-SWERL was used to estimate emissions of suspendible particles (particulate matter with aerodynamic diameters less than or equal to 10 micrometers) at different wind speeds. Filter samples, collected from the exhaust of the PI-SWERL during measurements, were analyzed for chemical composition. Based on nearly three years of data, the Gleason Fire site does not appear to have returned to pre burn wind erosion levels. Chemical composition data of suspendible particles are variable and show a trend toward pre-burn levels, but provide little insight into how the composition has been changing over time since the fire. Soil, runoff, and sediment data were collected from the Gleason Fire site to monitor the water erosion potential over the nearly three-year period. Soil hydrophobicity (water repellency) was noted on burned understory soils up to 12 months after the fire, as was the presence of ash on the soil surface. Soil deteriorated from a strong, definable pre-fire structure to a weakly cohesive mass (unstructured soil) immediately after the fire. Surface soil structure was evident 34 months after the fire at both burned and unburned sites, but was rare and weaker at burned sites. The amount of runoff and sediment was highly variable, but runoff occurred more frequently at burned interspace sites compared to burned understory and unburned interspace sites up to 34 months after the burn. No discernible pattern was evident on the amount of sediment transported, but the size of sediment from burned understory sites was almost double that of burned and unburned interspace soils after the fire, and decreased over the monitoring period. Curve numbers, a measure of the runoff potential, did not indicate any obvious runoff response to the fire. However, slight seasonal changes in curve numbers and runoff potential and, therefore, post-fire runoff response may be a function of fire impacts as well as the time of year that precipitation occurs. Site (interspace or understory) differences in soil properties and runoff persisted even after the fire. Vegetation data showed the presence of invasive grasses after the fire. Results from analysis of wind and water coupled with the spatial analysis of vegetation suggest that wind erosion may continue to occur due to the additional exposed soil surface (burned understory sites) until vegetation becomes re-established, and runoff may occur more frequently in interspace sites. The potential for fire-related wind erosion and water erosion may persist beyond three years in this system.« less

Soil heating and evaporation under extreme conditions: Forest fires and slash pile burns

NASA Astrophysics Data System (ADS)

Massman, W. J.

2011-12-01

Heating any soil during a sufficiently intense wild fire or prescribed burn can alter soil irreversibly, resulting in many significant and well known, long term biological, chemical, and hydrological effects. To better understand how fire impacts soil, especially considering the increasing probability of wildfires that is being driven by climate change and the increasing use of prescribe burns by land managers, it is important to better understand the dynamics of the coupled heat and moisture transport in soil during these extreme heating events. Furthermore, improving understanding of heat and mass transport during such extreme conditions should also provide insights into the associated transport mechanisms under more normal conditions as well. Here I describe the development of a new model designed to simulate soil heat and moisture transport during fires where the surface heating often ranges between 10,000 and 100,000 Wm-2 for several minutes to several hours. Model performance is tested against laboratory measurements of soil temperature and moisture changes at several depths during controlled heating events created with an extremely intense radiant heater. The laboratory tests employed well described soils with well known physical properties. The model, on the other hand, is somewhat unusual in that it employs formulations for temperature dependencies of the soil specific heat, thermal conductivity, and the water retention curve (relation between soil moisture and soil moisture potential). It also employs a new formulation for the surface evaporation rate as a component of the upper boundary condition, as well as the Newton-Raphson method and the generalized Thomas algorithm for inverting block tri-diagonal matrices to solve for soil temperature and soil moisture potential. Model results show rapid evaporation rates with significant vapor transfer not only to the free atmosphere above the soil, but to lower depths of the soil, where the vapor re-condenses ahead of the heating front. Consequently the trajectory of the solution (soil volumetric water content versus soil temperature) is very unusual and highly nonlinear, which may explain why more traditional methods (i.e., those based on finite difference or finite element approaches) tend to show more numerical instabilities than the Newton-Raphson method when used to model these extreme conditions. But, despite the intuitive and qualitative appeal of the model's numerical solution, it underestimates the rate of soil moisture loss observed during the laboratory trials, although the soil temperatures are reasonably well simulated.

Can earthworms survive fire retardants?

USGS Publications Warehouse

Beyer, W.N.; Olson, A.

1996-01-01

Most common fire retardants are foams or are similar to common agricultural fertilizers, such as ammonium sulfate and ammonium phosphate. Although fire retardants are widely applied to soils, we lack basic information about their toxicities to soil organisms. We measured the toxicity of five fire retardants (Firetrol LCG-R, Firetrol GTS-R, Silv-Ex Foam Concentrate, Phos-chek D-75, and Phos-chek WD-881) to earthworms using the pesticide toxicity test developed for earthworms by the European Economic Community. None was lethal at 1,000 ppm in the soil, which was suggested as a relatively high exposure under normal applications. We concluded that the fire retardants tested are relatively nontoxic to soil organisms compared with other environmental chemicals and that they probably do not reduce earthworm populations when applied under usual firefighting conditions.

Development of a model to predict ash transport and water pollution risk in fire-affected environments

NASA Astrophysics Data System (ADS)

Neris, Jonay; Elliot, William J.; Doerr, Stefan H.; Robichaud, Peter R.

2017-04-01

An estimated that 15% of the world's population lives in volcanic areas. Recent catastrophic erosion events following wildfires in volcanic terrain have highlighted the geomorphological instability of this soil type under disturbed conditions and steep slopes. Predicting the hydrological and erosional response of this soils in the post-fire period is the first step to design and develop adequate actions to minimize risks in the post-fire period. In this work we apply, for the first time, the Water Erosion Prediction Project model for predicting erosion and runoff events in fire-affected volcanic soils in Europe. Two areas affected by wildfires in 2015 were selected in Tenerife (Spain) representative of different fire behaviour (downhill surface fire with long residence time vs uphill crown fire with short residence time), severity (moderate soil burn severity vs light soil burn severity) and climatic conditions (average annual precipitation of 750 and 210 mm respectively). The actual erosion processes were monitored in the field using silt fences. Rainfall and rill simulations were conducted to determine hydrologic, interrill and rill erosion parameters. The soils were sampled and key properties used as model input, evaluated. During the first 18 months after the fire 7 storms produced runoff and erosion in the selected areas. Sediment delivery reached 5.4 and 2.5 Mg ha-1 respectively in the first rainfall event monitored after the fire, figures comparable to those reported for fire-affected areas of the western USA with similar climatic conditions but lower than those showed by wetter environments. The validation of the WEPP model using field data showed reasonable estimates of hillslope sediment delivery in the post-fire period and, therefore, it is suggested that this model can support land managers in volcanic areas in Europe in predicting post-fire hydrological and erosional risks and designing suitable mitigation treatments.

First application of the WEPP model to predict runoff and erosion risk in fire-affected volcanic areas in Europe

NASA Astrophysics Data System (ADS)

Neris, Jonay; Robichaud, Peter R.; Elliot, William J.; Doerr, Stefan H.; Notario del Pino, Jesús S.; Lado, Marcos

2017-04-01

An estimated that 15% of the world's population lives in volcanic areas. Recent catastrophic erosion events following wildfires in volcanic terrain have highlighted the geomorphological instability of this soil type under disturbed conditions and steep slopes. Predicting the hydrological and erosional response of this soils in the post-fire period is the first step to design and develop adequate actions to minimize risks in the post-fire period. In this work we apply, for the first time, the Water Erosion Prediction Project model for predicting erosion and runoff events in fire-affected volcanic soils in Europe. Two areas affected by wildfires in 2015 were selected in Tenerife (Spain) representative of different fire behaviour (downhill surface fire with long residence time vs uphill crown fire with short residence time), severity (moderate soil burn severity vs light soil burn severity) and climatic conditions (average annual precipitation of 750 and 210 mm respectively). The actual erosion processes were monitored in the field using silt fences. Rainfall and rill simulations were conducted to determine hydrologic, interrill and rill erosion parameters. The soils were sampled and key properties used as model input, evaluated. During the first 18 months after the fire 7 storms produced runoff and erosion in the selected areas. Sediment delivery reached 5.4 and 2.5 Mg ha-1 respectively in the first rainfall event monitored after the fire, figures comparable to those reported for fire-affected areas of the western USA with similar climatic conditions but lower than those showed by wetter environments. The validation of the WEPP model using field data showed reasonable estimates of hillslope sediment delivery in the post-fire period and, therefore, it is suggested that this model can support land managers in volcanic areas in Europe in predicting post-fire hydrological and erosional risks and designing suitable mitigation treatments.

Global Change Could Amplify Fire Effects on Soil Greenhouse Gas Emissions

PubMed Central

Niboyet, Audrey; Brown, Jamie R.; Dijkstra, Paul; Blankinship, Joseph C.; Leadley, Paul W.; Le Roux, Xavier; Barthes, Laure; Barnard, Romain L.; Field, Christopher B.; Hungate, Bruce A.

2011-01-01

Background Little is known about the combined impacts of global environmental changes and ecological disturbances on ecosystem functioning, even though such combined impacts might play critical roles in shaping ecosystem processes that can in turn feed back to climate change, such as soil emissions of greenhouse gases. Methodology/Principal Findings We took advantage of an accidental, low-severity wildfire that burned part of a long-term global change experiment to investigate the interactive effects of a fire disturbance and increases in CO2 concentration, precipitation and nitrogen supply on soil nitrous oxide (N2O) emissions in a grassland ecosystem. We examined the responses of soil N2O emissions, as well as the responses of the two main microbial processes contributing to soil N2O production – nitrification and denitrification – and of their main drivers. We show that the fire disturbance greatly increased soil N2O emissions over a three-year period, and that elevated CO2 and enhanced nitrogen supply amplified fire effects on soil N2O emissions: emissions increased by a factor of two with fire alone and by a factor of six under the combined influence of fire, elevated CO2 and nitrogen. We also provide evidence that this response was caused by increased microbial denitrification, resulting from increased soil moisture and soil carbon and nitrogen availability in the burned and fertilized plots. Conclusions/Significance Our results indicate that the combined effects of fire and global environmental changes can exceed their effects in isolation, thereby creating unexpected feedbacks to soil greenhouse gas emissions. These findings highlight the need to further explore the impacts of ecological disturbances on ecosystem functioning in the context of global change if we wish to be able to model future soil greenhouse gas emissions with greater confidence. PMID:21687708

Tundra fire disturbance homogonizes belowground food web structure, function and dynamics

NASA Astrophysics Data System (ADS)

Moore, J. C.; Pressler, Y.; Koltz, A.; Asmus, A.; Simpson, R.

2016-12-01

Tundra fires on Alaska's North Slope are on the rise due to increased lightning strikes since 2000. On July 16, 2007 lightning ignited the Anaktuvuk River fire, burning a 40-by-10 mile swath of tundra about 24 miles north of Toolik Field Station. The fire burned 401 square miles, was visible from space, and released more than 2.3 million tons of carbon into the atmosphere. A large amount of the organic layer of the soil was burned, changing the over all composition of the site and exposing deeper soil horizons. Due to fundamental transitions in soil characteristics and vegetation we hypothesized that the belowground food web community would be affected both in terms of biomass and location within the soil profile. Microbial biomass was reduced with burn severity. In the lower organic horizon there was a significant reduction in fungal biomass but we did not observe this effect in the upper organic soil. We did not observe a significant effect of burn severity on individual group biomass within higher trophic levels. Canonical Discriminant Analysis using the biomass estimates of the functional groups in the food webs found that the webs are becoming increasingly homogenized in the severely burned site compared to the moderately burned and unburned sites. The unburned soils differed significantly from soil at both burn sites; the greatest effects on food web structure were at the lower organic depth, whereas. We modeled the effects of the fire on soil organic matter processing rates and energy flow through the three food webs. The model estimated a decrease in C and N mineralization with fire severity, due in large part to the loss of organic material. While the organic horizon at the unburned site had 12 times greater C and N mineralization than the mineral soils, we observed little to no difference in C and N mineralization between the organic and mineral soil horizons in the moderately and severely burned sites. Our results show that the fire significantly altered the trophic structure of the soil food web, with loss of trophic complexity with increasing fire severity, which correlated strongly with C and N processing and food web stability.

Changes in Physical and Chemical Soil Properties on Burnt Shrub Areas in Mediterranean Mountains, Northern Portugal

NASA Astrophysics Data System (ADS)

Fonseca, Felícia; de Figueiredo, Tomás; Leite, Micaela

2014-05-01

Human induced fire in scrublands to obtain better pastures for cattle is a relatively common practice in North Portugal. During burning, plant cover and litter layers are consumed, and the mineral soil is heated, resulting in changes to physical, chemical, mineralogical, and biological soil properties. Aiming at evaluating the effect of this kind of fires on a set of physical and chemical soil properties, two study areas were selected in contrasting mountain environments: Edroso, Vinhais municipality, NE Portugal, with typical Mediterranean climate, and Revelhe, Fafe, NW Portugal, with a strong ocean-influenced climate. In both, sampling was carried out in contiguous areas burnt and not burnt, covered by shrub vegetation, predominantly Cytisus multiflorus and Ulex europeus. In each study area (Edroso and Revelhe) 16 locations were selected for soil sampling (8 in the burned area and 8 in the not burnt area), six months after fire occurrence. Disturbed soil samples were collected in the layers 0-5, 5-10, 10-15, 15-20 and 20-30 cm depth, for assessing organic matter, N, P and K concentration, cation exchange capacity and related determinations, soil pH, electrical conductivity and soil texture. Undisturbed samples were collected, in 100 cm3 cylinders, to determine bulk density in the same above mentioned layers, and permeability in the 0-5 cm layer. Compared results of burnt and not burnt areas in Edroso and Revelhe study sites, show that coarse elements content and permeability decreased and bulk density slightly increased with the fire effect. Chemical properties in both sites changed with after fire, as organic matter content, exchangeable Al and cation exchange capacity increased, the opposite trend being found for phosphorus, sum of exchangeable bases and electrical conductivity. Potassium, total nitrogen and exchangeable acidity showed different soil responses to fire in the two study areas. Results stress the clear effects of fire on fertility related soil properties, not only chemical but also physical, which is decisive for the post-fire recover of burnt shrub communities, in terms of vegetation and soil functions in these marginal mountain environments.

Effects of wild fires on the emissions of reactive gases from boreal and subarctic soils

NASA Astrophysics Data System (ADS)

Zhang-Turpeinen, Huizhong; Pumpanen, Jukka; Kivimäenpää, Minna

2017-04-01

Wild fire has long-term effects on the ecosystem and biological processes of boreal forest, and the frequency of wild fires is increasing as a consequence of climate change. Boreal forests lie largely on permafrost area, and the increase in fire frequency or intensity will affect the depth of the active layer on top of permafrost. The thawing of permafrost soils and increase in the active layer depth could induce significant reactive trace gas emissions. Biogenic volatile organic compounds (BVOCs) and nitrous acid (HONO) are closely associated with air chemistry in the troposphere. They react easily with ozone, hydroxyl radicals, and the reaction products may condense into aerosol particles or affect the growth of atmospheric aerosols which act as cloud condensation nuclei. Forests, and in particular permafrost soils, could be potentially large sources of BVOCs and HONO, because of the large amount of decomposing litter and soil organic matter. However, the forest soil BVOC emissions are poorly known, in contrast to BVOCs emitted from branch and canopy levels in boreal forests. The production rates of HONO in various soils are also poorly known. We studied BVOC and HONO fluxes from boreal forest soils and the effects of wild fires and the time since the last fire on them. We measured BVOCs emissions in west Siberia larch forest stands on permafrost soil in a fire chronosequence where the last forest fires had occurred 2, 24, and more than 100 years ago. HONO emissions in northern boreal subarctic Scots pine forest stands in Eastern Lapland in Finland in a fire chronosequence where the last fires had occurred 7, 47, 72 and 157 years ago. BVOC flux measurements were carried out by drawing air samples from chamber headspace into a steel adsorbent tube containing Tenax TA and carbopack B. The sampling tubes were analyzed on gas chromatography-mass spectrometry (GC-MS). Soil samples were measured for HONO flux in laboratory with LOPAP (Long path absorption photometer). According to our preliminary results the influence and the duration of the impact of forest fires were not observed in HONO emissions. However, the HONO emissions were sensitive to soil moisture. The unexpectedly high rate of release of isoprene measured in the middle age forest sites with warm scenario. Environmental parameters were correlated with the presence of BVOCs. We compared the BVOC fluxes with environmental parameters such as temperature, humidity and PAR, and with ground vegetation coverage and with litter input. The BVOC data is under processing still and more detail results is coming later.

The long-term effects on aggregate stability (AS) from a forest fire of varying intensity in a Mediterranean environment (1994-2012).

NASA Astrophysics Data System (ADS)

Velasco, Antonio; Alcañiz, Meritxell; Úbeda, Xavier; Pereira, Paulo; Mataix-Solera, Jorge

2013-04-01

Forest fires can affect many soil properties and this fact is deeply connected with fire severity, intensity, soil type and many others factors. Aggregate stability (AS) indicates the soil structure resilience in response to external mechanical forces. AS is one of the factors that strongly affect on soil erodibility and infiltration. This property can be used as an indicator of the state of the soil structure and physical stability. The aim of this study is to analyze the soil AS of a determined area that suffered a wildfire in 1994 and compare them with a control area with the same characteristics. The study area is located in the Cadiretes Massif, in the northernmost zone of the Catalan Coastal Ranges, northeast Spain, at an altitude of around 190 - 250 m.a.m.s.l. The Cadiretes Massif is predominantly granite, although soils developed over Paleozoic metamorphic rocks such as schist and slates can also be found. In some areas metamorphic features underlie this relief. The massif is covered by dense Mediterranean vegetation, e.g. Quercus suber, Arbutus unedo, Erica arborea, and in some places Pinus pinaster plantations are found. This area receives about 700 - 800 mm of annual rainfall, with a fairly marked seasonal variability. The maximum is registered in autumn. Summer temperatures often surpass 25°C, while in winter temperatures are generally mild. The predominant soil type in Cadiretes is classified as a Lithic Xerept, with a 15 cm deep sandy-loam A horizon. In the control forest area, this horizon is protected by a 3 cm deep O horizon of moder humus. Three areas with different burnt intensity were identified in 1994 and they are the same plots that were chosen to sample in 2012. The 4 plots (Low intensity, Medium Intensity, High Intensity and Control) had the same orientation (S) and slope (5%). The TDI (Ten Drop Impact) test, that simulates rainfall impact on aggregates, was used to measure AS in the laboratory. Twenty samples were collected per plot. Ten aggregates for each plot, of 4 - 4.8 mm were selected and subjected to the impact of 10 drops from a burette fixed at a height of 1 m. the aggregates were placed on a 2.8 mm sieve to allow the disaggregated sample to flow away. The drops of distilled water weighed 0.1 ± 0.001 g and had a diameter of 5.8 mm. The statistical comparison between the four treatments (high, medium and low intensity and control area) in 2012 samples shows that the disintegration percentage is higher in the high intensity area (13.5%). Medium and low intensity areas showed less percentage of aggregate disintegration: 10.4 and 11.1 respectively but still higher than the control area's one (5.45%). This analysis has demonstrated that after 18 years there are still significant AS differences between the three areas with different burnt intensity and the control area. Keywords: forest fire, aggregate stability, TDI test, Mediterranean area

43 CFR 23.7 - Approval of exploration plan.

Code of Federal Regulations, 2010 CFR

2010-10-01

... showing topographic, cultural and drainage features; (3) A statement of proposed exploration methods, i.e... measures to be taken to prevent or control fire, soil erosion, pollution of surface and ground water...

Hydrologic responses to restored wildfire regimes revealed by soil moisture-vegetation relationships

NASA Astrophysics Data System (ADS)

Boisramé, Gabrielle; Thompson, Sally; Stephens, Scott

2018-02-01

Many forested mountain watersheds worldwide evolved with frequent fire, which Twentieth Century fire suppression activities eliminated, resulting in unnaturally dense forests with high water demand. Restoration of pre-suppression forest composition and structure through a variety of management activities could improve forest resilience and water yields. This study explores the potential for "managed wildfire", whereby naturally ignited fires are allowed to burn, to alter the water balance. Interest in this type of managed wildfire is increasing, yet its long-term effects on water balance are uncertain. We use soil moisture as a spatially-distributed hydrologic indicator to assess the influence of vegetation, fire history and landscape position on water availability in the Illilouette Creek Basin in Yosemite National Park. Over 6000 manual surface soil moisture measurements were made over a period of three years, and supplemented with continuous soil moisture measurements over the top 1m of soil in three sites. Random forest and linear mixed effects models showed a dominant effect of vegetation type and history of vegetation change on measured soil moisture. Contemporary and historical vegetation maps were used to upscale the soil moisture observations to the basin and infer soil moisture under fire-suppressed conditions. Little change in basin-averaged soil moisture was inferred due to managed wildfire, but the results indicated that large localized increases in soil moisture had occurred, which could have important impacts on local ecology or downstream flows.

Soil erosion after forest fires in the Valencia region

NASA Astrophysics Data System (ADS)

González-Pelayo, Óscar; Keizer, Jan Jacob; Cerdà, Artemi

2014-05-01

Soil erosion after forest fire is triggered by the lack of vegetation cover and the degradation of the physical, biological and chemical properties (Martí et al., 2012; Fernández et al., 2012; Guénon, 2013). Valencia region belongs to the west Mediterranean basin ("Csa", Köppen climate classification), with drought summer periods that enhance forest fire risk. The characteristics of the climate, lithology and land use history makes this region more vulnerable to soil erosion. In this area, fire recurrence is being increased since late 50s (Pausas, 2004) and post-fire erosion studies became more popular from 80's until nowadays (Cerdá and Mataix-Solera, 2009). Research in Valencia region has contributed significantly to a better understanding of the effect of spatial and temporal scale on runoff and sediment yield measurements. The main achievements concerns: a) direct measurement of erosion rates under a wide range of methodologies (natural vs simulated rainfall, open vs closed plots); from micro- to meso-plot and catchment scale in single (Rubio et al., 1994; Cerdà et al., 1995; Cerdà 1998a; 1998b; Llovet et al., 1998; Cerdà, 2001; Calvo-Cases et al., 2003; Andreu et al., 2001; Mayor et al., 2007; Cerdà and Doerr, 2008) and multiples fires (Campo et al., 2006; González-Pelayo et al., 2010a). Changes in soil properties (Sanroque et al., 1985; Rubio et al., 1997; Boix-Fayós, 1997; Gimeno-Garcia et al., 2000; Guerrero et al., 2001; Mataix-Solera et al., 2004; González-Pelayo et al., 2006; Arcenegui et al., 2008; Campo et al., 2008; Bodí et al., 2012), in post-fire vegetation patterns (Gimeno-García et al., 2007) and, studies on mitigation strategies (Bautista et al., 1996; Abad et al., 2000). b) Progress to understanding post-fire erosion mechanism and sediment movement (Boix-Fayós et al., 2005) by definition of thresholds for sediment losses; fire severity, slope angle, bedrock, rain characteristics, vegetation pattern and ecosystem resilience (Mayor et al., 2007; González-Pelayo et al., 2010b). The knowledge achieved on post-fire erosion must very valuable for new insights and new strategies for landscape management. This research will review the State-of-the-Art of the contribution of the research on soil erosion as a consequence of forest fires in the Valencia Region. The review will show the contribution of the pioneers in the 80's when the USLE and mapping was the main too, the use of plots under simulated and natural rainfall, and also the strategies to control the soil erosion. Acknowledgements The research projects GL2008-02879/BTE, LEDDRA 243857 and RECARE FP7 project 603498 supported this research. References Abad, N., Bautista, S., Blade, C., Caturla, R.N. 2000. Seeding and mulching as erosion control techniques after wildfires in the Valencia region. En P. Balabanis, D. Peter, A. Ghazi y M. Tsogas (Eds.), Mediterranean Desertification Research Results and Policy Implications. Directorate-General Research, vol. 2. European Commission, Brussels, 419-429. Andreu, V., Imeson, A.C., Rubio, J.L. 2001. Temporal changes in soil aggregates and water erosion after a wildfire in a Mediterranean pine forest. Catena. 44, 69-84. Arcenegui, V., Mataix-Solera, J., Guerrero, C., Zornoza, R., Mataix-Beneyto, J., García-Orenes, F., 2008. Immediate effects of wildfires on water repellency and aggregate stability in Mediterranean calcareous soils. Catena 74, 219-226. Bautista, S., Bellot, J., Vallejo, R. 1996. Mulching treatment for postfire soil conservation in a semiarid ecosystem. Arid Soil Research and Rehabilitation 10, 235-242. Bodí, M., Mataix-Solera, J., Stefan H. Doerr, S.H., Cerdà, A. 2012. The wettability of ash from burned vegetation and its relationship to Mediterranean plant species type, burn severity and total organic carbon content. Geoderma 160, 599-607. Boix-Fayos, C. 1997. The roles of texture and structure in the water retention capacity of burnt Mediterranean soils with varying rainfall. Catena 31, 219-236. Boix-Fayos, C., Martínez-Mena, M., Calvo-Cases, A., Castillo, V.M., Albadalejo, J. 2005. Concise review of interrill erosion studies in SE Spain (Alicante and Murcia): erosion rates and progress of knowledge from the 1980s. Land Degradation and Developement 16, 517-528. Calvo-Cases, A., Boix-Fayós, C., Imeson, A.C. 2003. Runoff generation, sediment movement and soil water behaviour on calcareous (limestone) slopes of some Mediterranean environments in southeast Spain. Geomorphology 50, 269-291. Campo, J., Andreu, V., Gimeno-García, E., González-Pelayo, O., Rubio, J.L. 2008. Aggregation of under canopy and bare soils in a Mediterranean environment affected by different fire intensities. Catena 74 (3), 212-218. Campo, J., Andreu, V., Gimeno-García, E., González, O., Rubio, J.L. 2006. Occurrence of soil erosion after repeated experimental fires in a Mediterranean environment. Geomorphology 82, 376-387. Cerdà A. 2001. Erosión hídrica del suelo en el territorio Valenciano. El estado de la cuestión a través de la revisión bibliográfica. Geoforma Ediciones: Logronho. A. 2001. Cerdá, A, Mataix-Solera, J. 2009. Incendios forestales en España. Ecosistemas terrestres y suelos. En: Cerdá y Mataix-Solera (Eds.), Efectos de los incendios forestales sobre los suelos en España. Universidad de Valencia, 2009. Cerdà, A. 1998a. Postfire dynamics of erosional processes under mediterranean climatic conditions. Zeitschrift für Geomorphologie, 42 (3) 373-398. Cerdà, A. 1998b. Changes in overland flow and infiltration after a rangeland fire in a Mediterranean scrubland. Hydrological Processes, 12, 1031-1042. Cerdà, A., Doerr, S.H. 2008. The effect of ash and needle cover on surface runoff and erosion in the immediate post-fire period. Catena, 74 , 256- 263. doi:10.1016/S0341-8162(02)00027-9 Cerdà, A., Imeson, A.C., Calvo, A. 1995. Fire and aspect induced differences on the erodibility and hydrology of soils at La Costera, Valencia, Southeast Spain. Catena 24, 289-304. Fernández, C., Vega, J. A., Jiménez, E., Vieira, D. C. S., Merino, A., Ferreiro, A., Fonturbel, T. 2012. Seedingand mulching + seeding effects on post-fire runoff, soil erosion and species diversity in Galicia (NW Spain). Land Degradation & Development, 23: 150- 156. DOI 10.1002/ldr.1064 Gimeno-García, Andreu, V., Rubio, J.L. 2000. Changes in organic matter, nitrogen, phosphorus and cations in soils as a result of fire and water erosion in a Mediterranean landscape. European Journal of Soil Science 51, 201-210. Gimeno-García, E., Andreu, V.,, Rubio, J.L., 2007. Influence of vegetation recovery on water erosion at short and medium-term after experimental fires in a Mediterranean shrubland. Catena 69, 150-160. González-Pelayo, O, Andreu, V., Gimeno-García, E., Campo, J., Rubio, J.L. 2010a. Effects of fire and vegetation cover on hydrological characteristics of a Mediterranean shrubland soil. Hydrological Processes 24, 1504-1513. González-Pelayo, O., Andreu, V., Campo, J., Gimeno-García, E., Rubio, J.L. 2006. Hydrological Properties of Mediterranean Soils Burned with Different Fire Intensities. Catena 68 (2-3), 186-193. González-Pelayo, O., Andreu, V., Campo, J., Gimeno-García, E., Rubio, J.L. 2010b. Rainfall influence on plot-scale runoff and soil loss from repeated burning in a Mediterranean-shrub ecosystem, Valencia, Spain. Geomorphology 118, 444-452. Guénon, R., Vennetier, M., Dupuy, N., Roussos, S., Pailler, A., Gros, R. 2013. Trends in recovery of Mediterranean soil chemical properties and microbial activities after infrequent and frequent wildfires. Land Degradation & Development, 24: 115- 128. DOI 10.1002/ldr.1109 Guerrero, C., Mataix-Solera, J., Navarro-Pedreño, J., García-Orenes, F. Gómez, I. 2001. Different patterns of aggregate stability in burned and restored soils. Arid Land Research and Management 15, 163-171. Llovet, J., Bautista, S., Giovanardi, F., Vallejo, V. R., 1998. Sediment production in burned catchments of eastern spain. Annales Geophysicae. C531. Martín, A., Díaz-Raviña, M., Carballas, T. 2012. Short- and medium-term evolution of soil properties in Atlantic forest ecosystems affected by wildfires. Land Degradation & Development, 23: 427- 439. DOI 10.1002/ldr.1078 Mataix-Solera, J., Doerr, S.H. 2004. Hydrophobic and aggregate stability in calcareous topsoils from fire-affected pine forest in southeastern Spain. Geoderma 118, 77-88. Mayor, A.G., Bautista, S., Llovet, L., Bellot, J. 2007. Post-fire hydrological and erosional responses of a Mediterranean landscape: Seven years of catchment-scale dynamics. Catena 71, 68-75. Pausas, J.G. 2004. Changes in fire and climate in the eastern Iberian Peninsula (Mediterranean basin). Climatic Change 63: 337-350. Rubio, J.L., Andreu, V., Cerni, R. 1994. A monitoring system for experimental soil erosion plots. In: Rickson, R.J. (Ed.), Conserving Soil Resources: European Perspectives. CAB International, Wallingford, pp. 127-135. Rubio, J.L., Forteza, J., Andreu,V., Cerní, R. 1997. Soil profile characteristics influencing runoff and soil erosion after forest fire: A case of study (Valencia, Spain). Soil Technology 11, 67-78. Sanroque, P., Rubio, J.L., Mansanet, J. 1985. Efectos de los incendios forestales en las propiedades del suelo, en la composición florística y en la erosión hídrica de zonas forestales de Valencia (España). Rev. Ecol. Biol. Sol. 22 (2), 131-147.

Post-fire geomorphic response in steep, forested landscapes: Oregon Coast Range, USA

NASA Astrophysics Data System (ADS)

Jackson, Molly; Roering, Joshua J.

2009-06-01

The role of fire in shaping steep, forested landscapes depends on a suite of hydrologic, biologic, and geological characteristics, including the propensity for hydrophobic soil layers to promote runoff erosion during subsequent rainfall events. In the Oregon Coast Range, several studies postulate that fire primarily modulates sediment production via root reinforcement and shallow landslide susceptibility, although few studies have documented post-fire geomorphic response. Here, we describe field observations and topographic analyses for three sites in the central Oregon Coast Range that burned in 1999, 2002, and 2003. The fires generated strongly hydrophobic soil layers that did not promote runoff erosion because the continuity of the layers was interrupted by pervasive discontinuities that facilitated rapid infiltration. At each of our sites, fire generated significant colluvial transport via dry ravel, consistent with other field-based studies in the western United States. Fire-driven dry ravel accumulation in low-order valleys of our Sulphur Creek site equated to a slope-averaged landscape lowering of 2.5 mm. Given Holocene estimates of fire frequency, these results suggest that fire may contribute 10-20% of total denudation across steep, dissected portions of the Oregon Coast Range. In addition, we documented more rapid decline of root strength at our sites than has been observed after timber harvest, suggesting that root strength was compromised prior to fire or that intense heat damaged roots in the shallow subsurface. Given that fire frequencies in the Pacific Northwest are predicted to increase with continued climate change, our findings highlight the importance of fire-induced dry ravel and post-fire debris flow activity in controlling sediment delivery to channels.

Spatial and temporal variations of soil moisture under Rosmarinus officinalis and Quercus coccifera in a burned soil

NASA Astrophysics Data System (ADS)

Gimeno-García, E.; Pascual-Aguilar, J. A.; Llovet, J.

2009-04-01

When studying surface runoff processes, measurement of the soil moisture content (SMC) at the surface could be used to identify sinks and sources areas of runoff. Surface soil moisture patterns variability have been studied in a burned Mediterranean semi-arid area. Since surface SMC and soil water repellency (SWR) are influenced by fire and vegetation (see previous abstract), and soil water dynamics and vegetation dynamics are functionally related, it could be expected to find some changes during the following months after fire when vegetation starts to recover. The identification of these changes is the main goal of this research. The study area is located at the municipality of Les Useres, 40 km from Castellón city (E Spain), where a wildfire occured in August 2007. We selected a burned SSE facing hillslope, located at 570 m a.s.l., with 12° slope angle, in which it was possible to identify the presence of two unique shrub species: Quercus coccifera L. and Rosmarinus officinalis L., which were distributed in a patchy mosaic. Twenty microsites with burned R. officinalis and eight microsites with burned Q. coccifera were selected in an area of 7 m wide by 14 m long. At the burned microsites, it was possible to distinguish three concentric zones (I, II and III) around the stumps showing differences on their soil surface appearance, which indicate a gradient of fire severity. Those differences were considered for field soil moisture measurements. Five measurements of SMC separated approximately 10 cm per zone at each microsite (n= 420) were carried out after different rainfall events. Volumetric soil moisture was measured by means of the moisture meter HH2 with ThetaProbe sensor type ML2x, 6 cm long. SMC was monitored on three occasions, always one day after the following rainfall events: (1) the first rainfall event after fire, when 11 mm were registered (Oct-07); (2) four months later than fire (Dec-07), after six consecutive raining days with a total rain volume of 172 mm; and (3) ten months after fire (Jun-08), when 50 mm were registered in the previous ten days. The spatial pattern of SMC was determined trough geostatistical analysis using GS+ software, calculating the semivariograms, to analyse the spatial correlation scale, interpolating data to estimate values of SMC at unsampled locations by means of kriging and finally, the results of kriging were displayed as different contour maps. Results showed that spatial pattern of SMC was highly variable, with important differences recorded within short distances. In fact, the range of spatial correlation (a0), which is the distance at that spatial correlation exists, varied between 0.5 to 1.4 m. A0 also varied according to the time from fire, with values of 0.5 m in the first rainfall after fire, 0.9 m four months later and 1.4 m ten months after fire occurs. This result suggests that the extent of the wettest areas increase as the vegetation recover. After the first rainfall, the SMC spatial pattern seems to be related to the soil microsite characteristics, mainly organic matter content, presence of hydrophobicity and soil clay content. Generally, the highest SMC (26-31%) appears at the burned bare soil areas. Four months later, as the same time as Q. coccifera resprouts, and in the R. officinalis microsites an important regrowth of Brachypodium resutum is observed, the spatial pattern of SMC changed according this plant cover distribution. This pattern is more clearly observed ten months after fire, when the highest SMC values were located at Q. coccifera and B. resutum areas (28-33%). At this time, no evidence of germination of R. officinalis (obligate seeder specie) was found. The lowest SMC (19-22%) appeared at the half lower part of the plot, where there was a central strip dominated by bare soil, with scarce presence of resprouter species. These results showed that at detailed working scale, the soil moisture pattern in this burned area was highly heterogeneous and the microsite characteristics (mainly soil properties and vegetation regrowth) seem to control the SMC spatial pattern. The interaction of soil-plant-water is more complex that the few environmental factors analysed here, and future research is needed to consider other site factors, such as microtopography, surface stoniness and outcrops, root density, between others. However, the obtained results reflect the capacity of vegetated patches to act as moisture holding areas ten months after fire occurs.

Soil physical property response to prescribed fire in two young longleaf pine stands on the Western Gulf Coastal Plain

Treesearch

Mary Anne Sword Sayer

2007-01-01

Prescribed fire every 2 to 4 years is an important component of longleaf pine ecosystem restoration. Under some circumstances, repeated fire could change soil physical properties on the Western Gulf Coastal Plain. The objective of this study was to evaluate the soil bulk density, porosity fractions, and plant-available water holding capacity of restored longleaf pine...

Can the invasive earthworm, Amynthas agrestis, be controlled with prescribed fire?

Treesearch

Hiroshi Ikeda; Mac A. Callaham Jr.; Joseph J. O' Brien; Benjamin S. Hornsby; Evelyn S. Wenk

2015-01-01

Biological invasions are one of the most significant global-scale problems caused by human activities. Earthworms function as ecosystem engineers in soil ecosystems because their feeding and burrowing activities fundamentally change the physical and biological characteristics of the soils they inhabit. As a result of this “engineering,” earthworm invasions can have...

Effects of fire on major forest ecosystem processes: an overview.

PubMed

Chen, Zhong

2006-09-01

Fire and fire ecology are among the best-studied topics in contemporary ecosystem ecology. The large body of existing literature on fire and fire ecology indicates an urgent need to synthesize the information on the pattern of fire effects on ecosystem composition, structure, and functions for application in fire and ecosystem management. Understanding fire effects and underlying principles are critical to reduce the risk of uncharacteristic wildfires and for proper use of fire as an effective management tool toward management goals. This overview is a synthesis of current knowledge on major effects of fire on fire-prone ecosystems, particularly those in the boreal and temperate regions of the North America. Four closely related ecosystem processes in vegetation dynamics, nutrient cycling, soil and belowground process and water relations were discussed with emphases on fire as the driving force. Clearly, fire can shape ecosystem composition, structure and functions by selecting fire adapted species and removing other susceptible species, releasing nutrients from the biomass and improving nutrient cycling, affecting soil properties through changing soil microbial activities and water relations, and creating heterogeneous mosaics, which in turn, can further influence fire behavior and ecological processes. Fire as a destructive force can rapidly consume large amount of biomass and cause negative impacts such as post-fire soil erosion and water runoff, and air pollution; however, as a constructive force fire is also responsible for maintaining the health and perpetuity of certain fire-dependent ecosystems. Considering the unique ecological roles of fire in mediating and regulating ecosystems, fire should be incorporated as an integral component of ecosystems and management. However, the effects of fire on an ecosystem depend on the fire regime, vegetation type, climate, physical environments, and the scale of time and space of assessment. More ecosystem-specific studies are needed in future, especially those focusing on temporal and spatial variations of fire effects through long-term experimental monitoring and modeling.

Carbon And Nitrogen Storage Of A Mediterranean-Type Shrubland In Response To Post-Fire Succession And Long-Term Experimental Nitrogen Deposition

NASA Astrophysics Data System (ADS)

Vourlitis, G. L.; Hentz, C. S.

2015-12-01

Mediterranean-type shublands are subject to periodic fire and high levels of atmospheric nitrogen (N) deposition. Little is known how N inputs interact with post-fire secondary succession to affect ecosystem carbon (C) and N storage and cycling. Thus, a field experiment was conducted in a chaparral stand located in NE San Diego County, USA that burned during a wildfire in July 2003 to test the hypotheses that rates of C and N storage would significantly increase in response to experimental N addition. The experimental layout consists of a randomized design where four-10 x 10 m plots received 5 gN m-2 (added N) in the fall of each year since 2003 and four-10 x 10 m plots served as un-manipulated controls. Aboveground biomass C and N pools and fluxes, including biomass and litter C and N pool size, litter production, net primary production (NPP), N uptake, and litter C and N mineralization were measured seasonally (every 3 months) for a period of 10 years. Belowground surface (0-10 cm) soil extractable N, pH, and total soil N and C pools and surface root biomass C and N pools were also measured seasonally for a period of 10 years, while N losses from leaching were measured over a shorted (8 year) period of time. Added N led to a rapid increase in soil extractable N and a decline in soil pH; however, total soil C and N storage have yet to be affected by N input. Added N plots initially had significantly lower C and N storage than control plots; however, rates of aboveground N and C storage became significantly higher added N plots after 4-5 years of exposure. N losses from leaching continue to be significantly higher in added N plots even with an increase in aboveground C and N storage. The impact of N enrichment on ecosystem C and N storage varied depending on the stage of succession, but the eventual N-induced increase in NPP has implications for fuel buildup and future fire intensity. While N enrichment acted to increase aboveground C and N storage, plots exposed to high N inputs lost substantially more N from leaching than control plots. These results indicate that post-fire chaparral shrublands tend to be "leaky" even though they are not yet "N-saturated." Recovering stands in high-N deposition areas will likely be large sources of N to groundwater and/or streams regardless of whether NPP is stimulated by N input.

Natural 'background' soil water repellency in conifer forests: its prediction and relationship to wildfire occurrence

NASA Astrophysics Data System (ADS)

Doerr, Stefan; Woods, Scott; Martin, Deborah; Casimiro, Marta

2013-04-01

Soils under a wide range of vegetation types exhibit water repellency following the passage of a fire. This is viewed by many as one of the main causes for accelerated post-fire runoff and soil erosion and it has often been assumed that strong soil water repellency present after wildfire is fire-induced. However, high levels of repellency have also been reported under vegetation types not affected by fire, and the question arises to what degree the water repellency observed at burnt sites actually results from fire. This study aimed at determining 'natural background' water repellency in common coniferous forest types in the north-western USA. Mature or semi-mature coniferous forest sites (n = 81), which showed no evidence of recent fires and had at least some needle cast cover, were sampled across six states. After careful removal of litter and duff at each site, soil water repellency was examined in situ at the mineral soil surface using the Water Drop Penetration Time (WDPT) method for three sub-sites, followed by col- lecting near-surface mineral soil layer samples (0-3 cm depth). Following air-drying, samples were fur- ther analyzed for repellency using WDPT and contact angle (hsl) measurements. Amongst other variables examined were dominant tree type, ground vegetation, litter and duff layer depth, slope angle and aspect, elevation, geology, and soil texture, organic carbon content and pH. 'Natural background' water repellency (WDPT > 5 s) was detected in situ and on air-dry samples at 75% of all sites examined irrespective of dominant tree species (Pinus ponderosa, Pinus contorta, Picea engelma- nii and Pseudotsuga menziesii). These findings demonstrate that the soil water repellency commonly observed in these forest types following burning is not necessarily the result of recent fire but can instead be a natural characteristic. The notion of a low background water repellency being typical for long- unburnt conifer forest soils of the north-western USA is therefore incorrect. It follows that, where pre-fire water repellency levels are not known or highly variable, post-fire soil water repellency conditions are an unreliable indicator in classifying soil burn severity. The terrain and soil variables examined showed, overall, no convincing relationship with the repellency levels observed (R2 < 0.15) except that repellency was limited in soils (i) developed over meta-sedimen- tary lithology and (ii) with clay contents >4%. This suggests that water repellency levels cannot be pre- dicted with confidence from common terrain or soil variables. This work is presented in the memory of the late Scott Woods, who was instrumental in the success of this study and an inspiration to us all.

Historical and modern roles of fire in pinyon-juniper

Treesearch

George E. Gruell

1999-01-01

Fire history investigations were carried out in three widely separated Great Basin pinyon-juniper woodlands in east-central Nevada, southeastern Oregon and northwestern Nevada, and western Nevada. Study results suggested frequent fires on deep soils that produced an abundance of fine fuels and infrequent fires on shallow soils and rocky sites where fuels were sparse....

The effect of fire on soil properties

Treesearch

Leonard F. DeBano

1991-01-01

Fire affects nutrient cycling and the physical, chemical, and biological properties of soils occupied by western montane forests. Combustion of litter and soil organic matter (OM) increases the availability of some nutrients, although others are volatilized (for example, N, P, S). Soil OM loss also affects cation exchange capacity, organic chelation, aggregate...

Importance of charcoal in determining the age and chemistry of organic carbon in surface soils

NASA Astrophysics Data System (ADS)

Krull, Evelyn S.; Swanston, Christopher W.; Skjemstad, Jan O.; McGowan, Janine A.

2006-12-01

Understanding the chemical character and turnover time of the oldest soil organic carbon (SOC) fraction is fundamental in deciphering soil carbon sequestration processes and the fate of soil-eroded carbon in aquatic sediments. Two main processes are thought to extend the turnover time of SOC: protection by the mineral matrix and chemical recalcitrance. Various oxidation methods have been proposed to isolate the oldest and most recalcitrant SOC fraction, which is often assumed to be black carbon (BC). However, few data have been published that confirm the chemical character of the isolated fractions. Using established and newly developed methods together with 13C-NMR spectroscopy and AMS dating, we show that protection by the mineral matrix prolonged the turnover time of SOC by tens of years, but long-term (hundreds of years) stabilization was controlled by the inherent recalcitrance of SOC, determined by the type of ecosystems. In ecosystem without significant fire occurrences, the older SOC pool was comparably small and was represented by alkyl carbon. In ecosystems with high fire frequency charcoal constituted the oldest SOC pool, and constituted up to 35% of the total SOC. By applying methods with different oxidative strengths, it was possible to isolate different age groups of charcoal with different degrees of weathering. Further substantiation of this finding could provide a much greater resolution of paleo-fire events. Our results demonstrate that fire frequency plays a dominant role in determining the chemical nature and 14C abundance of SOC and that the separation of age groups of charcoal provides a means to reconstruct detailed fire histories. Our results indicate that modeling SOC turnover, transport and sequestration for frequently burnt environments requires modification of existing models, specifying an input and decay function for the charcoal pool in different environments.

Impact of the post fire management in some soil chemical properties. First results.

NASA Astrophysics Data System (ADS)

Francos, Marcos; Pereira, Paulo; Alcañiz, Meritxell; Úbeda, Xavi

2016-04-01

Post-fire management after severe wildfires has impact on soil properties. In Mediterranean environments management of fire affected areas is a common practice. This intervention may change soil chemical properties of the soil such as major cations. The aim of this work is to study the impact of different types of forest management in soil extractable calcium, magnesium, sodium and potassium after a severe wildfire. The study area is located in Ódena (Catalonia, Spain). The wildfire occurred at July 27th of 2015 and burned 1235 ha. After the fire an experimental plot was designed 9 plots with 2x2 meters (4 square meters). The different managements were: a) clear-cuted area and wood removed, b) no treatment); and c) clear-cutted. The results of the first sampling showed significant differences among all treatments in extractable calcium, sodium and potassium. The amount of these extractable elements was high in clear-cutted treatment in comparison to the others. No differences were identified in extractable magnesium. Overall, in the immediate period after the fire, burned area management, changed the studied soil properties. We are currently studying the evolution of this soil properties in these plots with the time

Long-term changes in soil erosion due to forest fires. A rainfall simulation approach in Eastern Spain

NASA Astrophysics Data System (ADS)

Cerdà, Artemi; Keesstra, Saskia; Pereira, Paulo; Matrix-Solera, Jorge; Giménez-Morera, Antonio; Úbeda, Xavier; Francos, Marcos; Alcañiz, Meritxell; Jordán, Antonio

2016-04-01

Soils are affected by the impacts of wildfires (Dlapa et al., 2013; Pereira et al., 2014; Tsibart et al., 2014; Dlapa et al., 2015, Hedo et al., 2015; Tessler et al., 2015). Soil erosion rates are highly affected by forest fires due to the removal of the above ground vegetation, the heat impact on the soil, the reduction of the organic matter, the ash cover, and the changes introduced by the rainfall on the soil surface (Lasanta and Cerdà, 2005; Mataix-Solera et al., 2011; Novara et al., 2011; Novara et al., 2013; Keesstra et al., 2014; Hedo et al., 2015; Pereira, 2015). Most of the research carried out on forest fire affected land paid attention to the "window of disturbance", which is the period that the soil losses are higher than before the forest fire and that last for few years (Cerdà, 1998a; Cerdà 1998b, Pérez-Cabello et al., 2011; Bodí et al., 2011; Bodí et al., 2012; Pereira et al., 2013: Pereira et al., 2015). However, the spatial and temporal variability of soil erosion is very high as a result of the uneven temporal and spatial distribution of the rainfall (Novara et al., 2011; Bisantino et al., 2015; Gessesse et al., 2015; Ochoa et al., 2015), and the window of disturbance cannot be easily found under natural rainfall. In order to understand the evolution of soil erosion after forest fires it is necessary to monitor fire affected sites over a long period of time, which will enable the assessment of the period affected by the window of disturbance (see Cerdà and Doerr, 2005). However, it is also possible to do measurements and experiments in areas with a different fire history. This will give us information about the temporal changes in soil erosion after forest fire. To reduce the spatial variability of rainfall we can use simulated rainfall that can be applied at multiple site with the same rainfall intensity and duration. For this purpose rainfall simulation can be of great help, in the laboratory (Moreno et al., 2014; Sadegui et al., 2015; Carvalho et al., 2015; Lassu et al., 2015) or in the field (Cerdà et al., 1998c; Jordán et al., 2009; Prosdocimi et al., 2016). In order to determine how fire and post-fire changes change soil erosion rates we selected 12 research sites at the study area of the Massís del Caroig, Eastern Spain, which suffered different fires in the last century. The parent material is limestone in all study sites and the mean annual rainfall ranges from 480 to 550 mm per year in average. The vegetation consists of scrubland (Maquia) with different species. In the years after the fire Brachypodium retusum, Thymus vulgaris, Fumana Ericoides, Cistus Albidus, Ulex parviflorus or Rosmarinus officinalis regenerated, but after some years dense shrub cover develops with typical species such as Quercus coccifera, Quercus ilex, Pistacia lentiscus and Junyperus oxycedurs. Soils are shallow (0-30 cm depth) and distributed in pockets of soil mixed with rock outcrops. All the selected plots were located on the middle tram of the slopes to avoid differences, although previous studies showed no differences in infiltration rates, overland flow and soil erosion on the different trams of the slopes on limestone (Cerdà, 1998d). Each site was selected upon the last fire registered: 0, 1, 2, 3, 5, 9, 16, 24, 33, 44, 51, and 63 years after the last fire. The measurements were carried out in August 2013 by means of a portable rainfall simulator (Cerdà et al., 2009; Iserloh et al., 2013). Ten plots of 0.25 m2 were selected at each site. Rainfall simulation at 55 mm h-1 during one hour was applied. The results show that immediately after the wildfires the soil erosion was negligible due to the ash cover, which acted as mulch, meanwhile after few months (1 year after the fire) the highest soil losses were measured. After 5 years the soil losses had reduced significantly and after 16 years were negligible. Acknowledgements The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 603498 (RECARE project) and by the Spanish Government with the research Project CGL2013- 47862-C2-1-R. References Bisantino T., Bingner R., Chouaib W., Gentile F., Trisorio Liuzzi G. 2015. Estimation of runoff, peak discharge and sediment load at the event scale in a medium-size mediterranean watershed using the annagnps model. Land Degradation and Development, 26 (4), 340-355. DOI: 10. 1002/ldr. 2213 Bodí, M.B., Doerr, S.H., Cerdà, A., Mataix-Solera, J. 2012. Hydrological effects of a layer of vegetation ash on underlying wettable and water repellent soil. Geoderma, 191, 14-23. DOI: 10.1016/j.geoderma.2012.01.006 Bodí, M.B., Mataix-Solera, J., Doerr, S.H., Cerdà, A. 2011. The wettability of ash from burned vegetation and its relationship to Mediterranean plant species type,burn severity and total organic carbon content. Geoderma, 160 (3-4), 599-607. Carvalho, S.C.P., de Lima, J.L.M.P., de Lima, M.I.P. 2015. Increasing the Rainfall Kinetic Energy of Spray Nozzles by using Meshes. Land Degradation and Development, DOI: 10.1002/ldr.2349 Cerdà, A. 1998a.The influence of aspect and vegetation on seasonal changes in erosion under rainfall simulation on a clay soil in Spain. Canadian Journal of Soil Science, 78 (2), 321-330. Cerdà, A. 1998b. Changes in overland flow and infiltration after a rangeland fire in a Mediterranean scrubland. Hydrological Processes, 12 (7), 1031-1042. Cerdà, A. 1998c. Post-fire dynamics of erosional processes under Mediterranean climatic conditions(1998) Zeitschrift fur Geomorphologie, 42 (3), 373-398. Cerdà, A. 1998d. The influence of geomorphological position and vegetation cover on the erosional and hydrological processes on a Mediterranean hillslope. Hydrological Processes, 12 (4), 661-671. Cerdà, A., Doerr, S.H. 2005.Influence of vegetation recovery on soil hydrology and erodibility following fire: An 11-year investigation International Journal of Wildland Fire, 14 (4), 423-437. DOI: 10.1071/WF05044 Cerdà, A., Jurgensen, M.F., Bodi, M.B. 2009. Effects of ants on water and soil losses from organically-managed citrus orchards in eastern Spain. Biologia, 64 (3), 527-531. DOI: 10.2478/s11756-009-0114-7 Dlapa P., Bodí M.B., Mataix-Solera J., Cerdà A., Doerr S.H. 2015. Organic matter and wettability characteristics of wildfire ash from Mediterranean conifer forests. Catena, 135, 369-376. DOI: 10.1016/j.catena.2014.06.018 Dlapa, P., Bodí, M.B., Mataix-Solera, J., Cerdà, A., Doerr, S.H. 2013. FT-IR spectroscopy reveals that ash water repellency is highly dependent on ash chemical composition. Catena, 108, 35-43. DOI: 10.1016/j.catena.2012.02.011 Gessesse B., Bewket W., Bräuning A. 2015. Model-Based Characterization and Monitoring of Runoff and Soil Erosion in Response to Land Use/land Cover Changes in the Modjo Watershed, Ethiopia. (2015) Land Degradation and Development, 26 (7), 711-724.. DOI: 10. 1002/ldr. 2276 Hedo J., Lucas-Borja M. E., Wic C., Andrés-Abellán M., De Las Heras J. 2015. Soil microbiological properties and enzymatic activities of long-term post-fire recovery in dry and semiarid Aleppo pine (Pinus halepensis M.) forest stands. Solid Earth, 6 (1), 243-252. DOI: 10. 5194/se-6-243-2015 Hedo de Santiago, J., Lucas-Borja, M.E., Wic-Baena, C., Andrés-Abellán, M., de las Heras, J. 2015. Effects of thinning and induced drought on microbiological soil properties and plant species diversity at dry and semiarid locations. Land Degradation and Development, DOI: 10.1002/ldr.2361 Iserloh, T., Ries, B.J., Cerdà, A., Echeverría, M.T., Fister, W., Geißler, C., Kuhn, N.J., León, F.J., Peters, P., Schindewolf, M., Schmidt, J., Scholten, T., Seeger, M. 2013. Comparative measurements with seven rainfall s simulators on uniform bare fallow land. Zeitschrift fur Geomorphologie, 57 (1 SUPPL. 1), 1-10. DOI: 10.1127/0372-8854/2012/S-00085 Jordán-López, A., Martínez-Zavala, L., Bellinfante, N. 2009. Impact of different parts of unpaved forest roads on runoff and sediment yield in a Mediterranean area. Science of the total environment, 407(2), 937-944. Keesstra, S.D., Maroulis, J., Argaman, E., Voogt, A., Wittenberg, L, 2014. Effects of controlled fire on hydrology and erosion under simulated rainfall. Cuadernos de Investigación Geográfica 40, 269-293. DOI: 10.18172/cig.2532 Lasanta, T., Cerdà, A. 2005. Long-term erosional responses after fire in the Central Spanish Pyrenees: 2. Solute reléase. Catena, 60 (1), 81-100. DOI: 10.1016/j.catena.2004.09.005 Lassu, T., Seeger, M., Peters, P., Keesstra, S.D. 2015. The Wageningen Rainfall Simulator: Set-up and Calibration of an Indoor Nozzle-Type Rainfall Simulator for Soil Erosion Studies. Land Degradation and Development, 26 (6), 604-612. DOI: 10.1002/ldr.2360 Mataix-Solera, J., Cerdà, A., Arcenegui, V., Jordán, A., Zavala, L.M. 2011. Fire effects on soil aggregation: A review. Earth-Science Reviews, 109 (1-2), 44-60. DOI: 10.1016/j.earscirev.2011.08.002 Moreno-Ramón, H., Quizembe, S.J., Ibáñez-Asensio, S. 2014. Coffee husk mulch on soil erosion and runoff: Experiences under rainfall simulation experiment. Solid Earth, 5 (2), 851-862. DOI: 10.5194/se-5-851-2014 Novara A., Gristina L., Rühl J., Pasta S., D'Angelo G., La Mantia T., Pereira P. 2013. Grassland fire effect on soil organic carbon reservoirs in a semiarid environment. Solid Earth, 4 (2), 381-385.. DOI: 10. 5194/se-4-381-2013 Novara, A., Gristina, L., Bodì, M.B., Cerdà, A. 2011. The impact of fire on redistribution of soil organic matter on a Mediterranean hillslope under maquia vegetation type Land Degradation and Development, 22 (6), 530-536. DOI: 10.1002/ldr.1027 Novara, A., Gristina, L., Saladino, S.S., Santoro, A., Cerdà, A. 2011. Soil erosion assessment on tillage and alternative soil managements in a Sicilian vineyard. Soil and Tillage Research, 117, 140-147. DOI: 10.1016/j.still.2011.09.007 Ochoa-Cueva P., Fries A., Montesinos P., Rodríguez-Díaz J. A., Boll J. 2015. Spatial Estimation of Soil Erosion Risk by Land-cover Change in the Andes OF Southern Ecuador. Land Degradation and Development, 26 (6), 565-573DOI: 10. 1002/ldr. 2219 Pereira, P., Cerdà, A., Úbeda, X., Mataix-Solera, J., Arcenegui, V., Zavala, L.M. 2015. Modelling the Impacts of Wildfire on Ash Thickness in a Short-Term Period. Land Degradation and Development, 26 (2), 180-192. DOI: 10.1002/ldr.2195 Pereira, P., Cerdà, A., Úbeda, X., Mataix-Solera, J., Martin, D., Jordán, A., Burguet, M. 2013. Spatial models for monitoring the spatio-temporal evolution of ashes after fire and ash; A case study of a burnt grassland in Lithuania. Solid Earth, 4 (1), 153-165 DOI: 10.5194/se-4-153-2013 Pereira, P., Jordán, A., Cerdà, A., Martin, D. 2015. Editorial: The role of ash in fire-affected ecosystem. Catena, . DOI: 10.1016/j.catena.2014.11.016 Pereira, P., Úbeda, X., Mataix-Solera, J., Oliva, M., Novara, A.Short-term changes in soil Munsell colour value, organic matter content and soil water repellency after a spring grassland fire in Lithuania (2014) Solid Earth, 5 (1), 209-225. DOI: 10.5194/se-5-209-2014 Pérez-Cabello, F., Cerdà, A., de la Riva, J., Echeverría, M.T., García-Martín, A., Ibarra, P., Lasanta, T., Montorio, R., Palacios, V. 2012. Micro-scale post-fire surface cover changes monitored using high spatial resolution photography in a semiarid environment: A useful tool in the study of post-fire soil erosion processes. Journal of Arid Environments, 76 (1), 88-96. DOI: 10.1016/j.jaridenv.2011.08.007 Prosdocimi,M., Jordán, A., Tarolli, P., Keesstra, S., Novara, A., Cerdà, A. 2016. The immediate effectiveness of barley straw mulch in reducing soil erodibility and surface runoff generation in Mediterranean vineyards. Science of The Total Environment, 547, 15 ,323-330, doi:10.1016/j.scitotenv.2015.12.076 Sadeghi, S.H.R., Gholami, L., Sharifi, E., Khaledi Darvishan, A., Homaee, M. 2015. Scale effect on runoff and soil loss control using rice mulch under laboratory conditions. Solid Earth, 6 (1), 1-8. DOI: 10.5194/se-6-1-2015 Tessler, N., Sapir, Y., Wittenberg, L., Greenbaum, N. 2015. Recovery of Mediterranean Vegetation after Recurrent Forest Fires: Insight from the 2010 Forest Fire on Mount Carmel, Israel. Land Degradation and Development, DOI: 10.1002/ldr.2419 Tsibart, A., Gennadiev, A., Koshovskii, T., Watts, A. 2014. Polycyclic aromatic hydrocarbons in post-fire soils of drained peatlands in western Meshchera (Moscow region, Russia). Solid Earth, 5 (2), 1305-1317. DOI: 10.5194/se-5-1305-2014 Wang, C., Wang, G., Wang, Y., Rafique, R., Ma, L., Hu, L., Luo, Y. 2015. Fire Alters Vegetation and Soil Microbial Community in Alpine Meadow. Land Degradation and Development, . DOI: 10.1002/ldr.2367

FEMME- post-Fire Emergency ManageMEnt tool.

NASA Astrophysics Data System (ADS)

Vieira, Diana; Serpa, Dalila; Rocha, João; Nunes, João; Keizer, Jacob

2017-04-01

Wildfires can have important impacts on hydrological and soil erosion processes in forest catchments, due to the destruction of vegetation cover and changes to soil properties. The involved processes however, are non-linear and not fully understood. This has severely limited the understanding on the impacts of wildfires, and, as a consequence, current runoff-erosion models are poorly adapted to recently burned forest conditions. Furthermore, while post-fire forestry operations and, to a lesser extent, post-fire soil conservation measures are commonly applied, their hydrological and erosion impacts continue poorly known, hampering decision-making by land owners and managers. Past post-wildfire research in Portugal has involved simple adaptations of plot-scale runoff-erosion models to post-fire conditions. This follow-up study focusses on model adaptation to selected post-fire soil conservation measures. To this end, full stock is taken of various datasets collected by several (past and ongoing research projects. The selected model is the Morgan-Morgan-Finney model (MMF, Morgan,2001), which already proved its suitability for post-fire conditions in Portugal (Vieira et al, 2010, 2014) as well as NW-Spain ( Fernández et al., 2010). The present results concerned runoff and erosion different burn severities and various post-fire mitigation treatments (mulch, hydromulch, needle cast, barriers), focussing on the plot and field scale. The results for both the first and the second year following the wildfire revealed good model efficiency, not only for burned and untreated conditions but also for burned and treated conditions. These results thus reinforced earlier findings that MMF is a suitable model for the envisaged post-fire soil erosion assessment tool, coined "FEMME". The data used for post-fire soil erosion calibration with the MMF already allows the delineation of the post-fire management FEMME tool. Nevertheless, further model assessment will address additional post-fire forestry operations (e.g. plowing) as well as upscaling to the catchment scale with the MMF model and compare it with the SWAT model.

The impact of wildland fires on calcareous Mediterranean pedosystems (Sardinia, Italy) - An integrated multiple approach.

PubMed

Capra, Gian Franco; Tidu, Simona; Lovreglio, Raffaella; Certini, Giacomo; Salis, Michele; Bacciu, Valentina; Ganga, Antonio; Filzmoser, Peter

2018-05-15

Sardinia (Italy), the second largest island of the Mediterranean Sea, is a fire-prone land. Most Sardinian environments over time were shaped by fire, but some of them are too intrinsically fragile to withstand the currently increasing fire frequency. Calcareous pedoenvironments represent a significant part of Mediterranean areas, and require important efforts to prevent long-lasting degradation from fire. The aim of this study was to assess through an integrated multiple approach the impact of a single and highly severe wildland fire on limestone-derived soils. For this purpose, we selected two recently burned sites, Sant'Antioco and Laconi. Soil was sampled from 80 points on a 100×100m grid - 40 in the burned area and 40 in unburned one - and analyzed for particle size fractions, pH, electrical conductivity, organic carbon, total N, total P, and water repellency (WR). Fire behavior (surface rate of spread (ROS), fireline intensity (FLI), flame length (FL)) was simulated by BehavePlus 5.0.5 software. Comparisons between burned and unburned areas were done through ANOVA as well as deterministic and stochastic interpolation techniques; multiple correlations among parameters were evaluated by principal factor analysis (PFA) and differences/similarities between areas by principal component analysis (PCA). In both sites, fires were characterized by high severity and determined significant changes to some soil properties. The PFA confirmed the key ecological role played by fire in both sites, with the variability of a four-modeled components mainly explained by fire parameters, although the induced changes on soils were mainly site-specific. The PCA revealed the presence of two main "driving factors": slope (in Sant'Antioco), which increased the magnitude of ROS and FLI; and soil properties (in Laconi), which mostly affected FL. In both sites, such factors played a direct role in differentiating fire behavior and sites, while they played an indirect role in determining some effects on soil. Copyright © 2017 Elsevier B.V. All rights reserved.

The role of fire on soil mounds and surface roughness in the Mojave Desert

USGS Publications Warehouse

Soulard, Christopher E.; Esque, Todd C.; Bedford, David R.; Bond, Sandra

2013-01-01

A fundamental question in arid land management centers on understanding the long-term effects of fire on desert ecosystems. To assess the effects of fire on surface topography, soil roughness, and vegetation, we used terrestrial (ground-based) LiDAR to quantify the differences between burned and unburned surfaces by creating a series of high-resolution vegetation structure and bare-earth surface models for six sample plots in the Grand Canyon-Parashant National Monument, Arizona. We find that 11 years following prescribed burns, mound volumes, plant heights, and soil-surface roughness were significantly lower on burned relative to unburned plots. Results also suggest a linkage between vegetation and soil mounds, either through accretion or erosion mechanisms such as wind and/or water erosion. The biogeomorphic implications of fire-induced changes are significant. Reduced plant cover and altered soil surfaces from fire likely influence seed residence times, inhibit seed germination and plant establishment, and affect other ecohydrological processes.

Soil humic-like organic compounds in prescribed fire emissions using nuclear magnetic resonance spectroscopy.

PubMed

Chalbot, M-C; Nikolich, G; Etyemezian, V; Dubois, D W; King, J; Shafer, D; Gamboa da Costa, G; Hinton, J F; Kavouras, I G

2013-10-01

Here we present the chemical characterization of the water-soluble organic carbon fraction of atmospheric aerosol collected during a prescribed fire burn in relation to soil organic matter and biomass combustion. Using nuclear magnetic resonance spectroscopy, we observed that humic-like substances in fire emissions have been associated with soil organic matter rather than biomass. Using a chemical mass balance model, we estimated that soil organic matter may contribute up to 41% of organic hydrogen and up to 27% of water-soluble organic carbon in fire emissions. Dust particles, when mixed with fresh combustion emissions, substantially enhances the atmospheric oxidative capacity, particle formation and microphysical properties of clouds influencing the climatic responses of atmospheric aeroso. Owing to the large emissions of combustion aerosol during fires, the release of dust particles from soil surfaces that are subjected to intense heating and shear stress has, so far, been lacking. Copyright © 2013 Elsevier Ltd. All rights reserved.

Characterization of soil phosphorus in a fire-affected forest Cambisol by chemical extractions and (31)P-NMR spectroscopy analysis.

PubMed

Turrion, María-Belén; Lafuente, Francisco; Aroca, María-José; López, Olga; Mulas, Rafael; Ruipérez, Cesar

2010-07-15

This study was conducted to investigate the long-term effects of fire on soil phosphorus (P) and to determine the efficiency of different procedures in extracting soil P forms. Different P forms were determined: labile forms (Olsen-P, Bray-P, and P extracted by anion exchange membranes: AEM-P); moderately labile inorganic and organic P, obtained by NaOH-EDTA extraction after removing the AEM-P fraction; and total organic and inorganic soil P. (31)P-NMR spectroscopy was used to characterize the structure of alkali-soluble P forms (orthophosphate, monoester, pyrophosphate, and DNA). The studied area was a Pinus pinaster forest located at Arenas de San Pedro (southern Avila, Spain). The soils were Dystric Cambisols over granites. Soil samples were collected at 0-2 cm, 2-5 cm, and 10-15 cm depths, two years after a fire in the burned area and in an adjacent unburned forest area. Fire increased the total N, organic C, total P, and organic and inorganic P content in the surface soil layer. In burned soil, the P extracted by the sequential procedure (AEM and NaOH+EDTA) was about 95% of the total P. Bray extraction revealed a fire-induced increase in the sorption surfaces. Analysis by chemical methods overestimated the organic P fraction in the EDTA-NaOH extract in comparison with the determination by ignition procedure. This overestimation was more important in the burned than unburned soil samples, probably due to humification promoted by burning, which increased P sorption by soil particles. The fire-induced changes on the structure of alkali-soluble P were an increase in orthophosphate-P and a decrease in monoester-P and DNA-P. Copyright 2010 Elsevier B.V. All rights reserved.

Prescribed burning supports grassland biodiversity - A multi-species study

NASA Astrophysics Data System (ADS)

Valkó, Orsolya; Deák, Balázs; Magura, Tibor; Török, Péter; Kelemen, András; Tóth, Katalin; Horváth, Roland; Nagy, Dávid; Debnár, Zsuzsanna; Zsigrai, György; Kapocsi, István; Tóthmérész, Béla

2017-04-01

During ancient times, fire was an important factor shaping European landscapes. Nowadays, prescribed burning can be one of the most effective conservation tools for the management of open landscapes, controlling dominant species, reducing accumulated litter or decreasing wildfire risk. In a prescribed burning experiment, we studied the effects of fire on dry alkaline grasslands. We tested whether autumn prescribed burning can be an alternative conservation measure in these grasslands. We selected six sites in Hungary: in three sites, prescribed burning was applied in November 2011, while three sites remained unburnt. We studied the effects of fire on soil characteristics, plant biomass and on the vegetation and arthropod assemblages (isopods, spiders, ground beetles and rove beetles). Soluble salt content increased significantly in the burnt sites, but soil pH, organic matter, potassium and phosphorous did not change. We found that prescribed fire had several positive effects from the nature conservation viewpoint. Diversity and the number of flowering shoots were higher, and the cover of the dominant grass was lower in the burnt sites. Graminoid biomass was lower, while total, green and forb biomass were higher in the burnt plots compared to the control ones. Our findings suggest that prescribed burning fire did not harm arthropods; species-level analyses showed that out of the most abundant invertebrate species, the abundance of ten was not affected, one decreased and one increased after burning. Our findings highlight that mosaic prescribed fire is a viable management tool in open landscapes, because it supports plant diversity and does not threaten arthropods.

The secret life of microbes: soil bacteria and fungi undaunted by the harvesting of fire-killed trees

Treesearch

Paul Meznarich; Jane Smith; Tara Jennings

2013-01-01

Soil health is fundamental to ecosystem health. Disturbances such as fire and timber harvesting can affect the abundance, activity, and composition of soil microbial communities and thus affect soil productivity. In response to forest managers, scientists with the Pacific Northwest Research Station compared health and productivity indicators between soils disturbed by...

25 CFR 216.6 - Approval of exploration plan.

Code of Federal Regulations, 2011 CFR

2011-04-01

... control fire, soil erosion, pollution of surface and ground water, damage to fish and wildlife or other... supervisor may, with respect to such a plan, exercise the authority provided by paragraphs (f) and (g) of...

43 CFR 23.7 - Approval of exploration plan.

Code of Federal Regulations, 2013 CFR

2013-10-01

... within which exploration is to be conducted; (2) Two copies of a suitable map or aerial photograph... measures to be taken to prevent or control fire, soil erosion, pollution of surface and ground water...

43 CFR 23.7 - Approval of exploration plan.

Code of Federal Regulations, 2012 CFR

2012-10-01

... within which exploration is to be conducted; (2) Two copies of a suitable map or aerial photograph... measures to be taken to prevent or control fire, soil erosion, pollution of surface and ground water...

43 CFR 23.7 - Approval of exploration plan.

Code of Federal Regulations, 2014 CFR

2014-10-01

... within which exploration is to be conducted; (2) Two copies of a suitable map or aerial photograph... measures to be taken to prevent or control fire, soil erosion, pollution of surface and ground water...

Effect of fire severity on physical and biochemical soil properties in Zagros oak (Quercus brantii Lindl.) forests in Iran

Treesearch

M. Heydari; A. Rostamy; F. Najafi; D. C. Dey

2017-01-01

Fire affects the physical and chemical properties and soil biological activity of natural ecosystems. This study was conducted in the Miyan Tang region, Ilam Province in western Iran. The study site was 110 hectares, where we sampled soils in areas that were classified by fire severity: low (LS), high (HS) and medium severity (MS), and unburned (UB), which served as...

Effects of post-fire salvage logging and a skid trail treatment on ground cover, soils, and sediment production in the interior western United States

Treesearch

Joseph W. Wagenbrenner; Lee H. MacDonald; Robert N. Coats; Peter R. Robichaud; Robert E. Brown

2015-01-01

Post-fire salvage logging adds another set of environmental effects to recently burned areas, and previous studies have reported varying impacts on vegetation, soil disturbance, and sediment production with limited data on the underlying processes. Our objectives were to determine how: (1) ground-based post-fire logging affects surface cover, soil water repellency,...

Interactive effects of climate, hydrology and fire on nitrogen retention and export in coastal California chaparral

NASA Astrophysics Data System (ADS)

Hanan, E. J.; Schimel, J.; Tague, C.

2012-12-01

Fire is a major restructuring force in Mediterranean-type ecosystems, inducing nutrient redistribution that is frequently invoked as a driver of ecosystem recovery. Fire regimes are expected to change with climate warming and associated droughts. To study watershed responses to high severity landscape fire, we combined ground-based sampling of soil nitrogen dynamics with modeling in two burned, chaparral-dominated watersheds. These two watersheds, Mission Canyon and Rattlesnake Canyon, span the foothills of the Santa Ynez Mountains in Santa Barbara County, California, and large portions of both watersheds burned in November 2008 and/or May 2009. We established fifteen burned and three unburned plots in November 2009 and monitored them on a monthly basis through June 2011 for a variety of ecosystem properties including water content, soil and foliar carbon and nitrogen, soil pH, exchangeable inorganic nitrogen, and microbial biomass. We then used the GIS-based hydro-biogeochemical model, Regional Hydro-Ecologic Simulation System (RHESSys) to to evaluate the effects of fire season, climate and hydrology on biogeochemical fluxes across the fire-scarred watersheds. Fires were imposed at the beginning and end of the growing season under various climates. Soil samples collected prior to the onset of rain were relatively enriched in ammonium, presumably due to ash residue deposition. Storm events then stimulated nitrification and pulses of mineralization. Ephemeral herbs established quickly following the first post-fire rain events, thereby maintaining ecosystem nutrient capital as shrubs gradually returned. Nitrate production was significantly enhanced in burned chaparral perhaps because fires elevated soil pH, which can both raise the solubility of soil organic matter, and stimulate nitrification, or perhaps because fires released nitrifying bacteria from competition with vegetation for ammonium. Overall however, nitrogen retention and export varied among plots, highlighting the complexity of ecosystem response to fire. Modeling results suggest that chaparral nutrients pools recover more slowly when fires occur at the end of the growing season, prior to the hot, dry summer. Thus climate impacts on the timing of fire are likely to alter trajectories of ecosystem recovery.

[Factors affecting the vegetation restoration after fires in cold temperate wetlands: A review].

PubMed

Zhao, Feng-Jun; Wang, Li-Zhong; Shu, Li-Fu; Chen, Peng-Yu; Chen, Li-guang

2013-03-01

Cold temperate wetland plays an important role in maintaining regional ecological balance. Fire is an important disturbance factor in wetland ecosystem. Severe burning can induce the marked degradation of the ecological functions of wetland ecosystem. The vegetation restoration, especially the early vegetation restoration, after fires, is the premise and basis for the recovery of the ecological functions of the ecosystem. This paper reviewed the research progress on the factors affecting the vegetation restoration after fires in wetlands. The vegetation restoration after fires in cold temperate wetlands was controlled by the fire intensity, fire size, vegetation types before fires, regeneration characteristics of plant species, and site conditions. It was considered that the long-term monitoring on the post-fire vegetation restoration in cold temperate wetland, the key factors affecting the vegetation restoration, the roles of frozen soil layer on the post-fire vegetation restoration, and the theories and technologies on the vegetation restoration would be the main research directions in the future.

The sensitivity of US wildfire occurrence to pre-season soil moisture conditions across ecosystems.

PubMed

Jensen, Daniel; Reager, John T; Zajic, Brittany; Rousseau, Nick; Rodell, Matthew; Hinkley, Everett

2018-01-01

It is generally accepted that year-to-year variability in moisture conditions and drought are linked with increased wildfire occurrence. However, quantifying the sensitivity of wildfire to surface moisture state at seasonal lead-times has been challenging due to the absence of a long soil moisture record with the appropriate coverage and spatial resolution for continental-scale analysis. Here we apply model simulations of surface soil moisture that numerically assimilate observations from NASA's Gravity Recovery and Climate Experiment (GRACE) mission with the US Forest Service's historical Fire-Occurrence Database over the contiguous United States. We quantify the relationships between pre-fire-season soil moisture and subsequent-year wildfire occurrence by land-cover type and produce annual probable wildfire occurrence and burned area maps at 0.25-degree resolution. Cross-validated results generally indicate a higher occurrence of smaller fires when months preceding fire season are wet, while larger fires are more frequent when soils are dry. This result is consistent with the concept of increased fuel accumulation under wet conditions in the pre-season. These results demonstrate the fundamental strength of the relationship between soil moisture and fire activity at long lead-times and are indicative of that relationship's utility for the future development of national-scale predictive capability.

The sensitivity of US wildfire occurrence to pre-season soil moisture conditions across ecosystems

NASA Astrophysics Data System (ADS)

Jensen, Daniel; Reager, John T.; Zajic, Brittany; Rousseau, Nick; Rodell, Matthew; Hinkley, Everett

2018-01-01

It is generally accepted that year-to-year variability in moisture conditions and drought are linked with increased wildfire occurrence. However, quantifying the sensitivity of wildfire to surface moisture state at seasonal lead-times has been challenging due to the absence of a long soil moisture record with the appropriate coverage and spatial resolution for continental-scale analysis. Here we apply model simulations of surface soil moisture that numerically assimilate observations from NASA’s Gravity Recovery and Climate Experiment (GRACE) mission with the USDA Forest Service’s historical Fire-Occurrence Database over the contiguous United States. We quantify the relationships between pre-fire-season soil moisture and subsequent-year wildfire occurrence by land-cover type and produce annual probable wildfire occurrence and burned area maps at 0.25 degree resolution. Cross-validated results generally indicate a higher occurrence of smaller fires when months preceding fire season are wet, while larger fires are more frequent when soils are dry. This is consistent with the concept of increased fuel accumulation under wet conditions in the pre-season. These results demonstrate the fundamental strength of the relationship between soil moisture and fire activity at long lead-times and are indicative of that relationship’s utility for the future development of national-scale predictive capability.

Burn Severity and Its Impact on Soil Properties: 2016 Erskine Fire in the Southern Sierra Nevada

NASA Astrophysics Data System (ADS)

Haake, S.; Guo, J.; Krugh, W. C.

2017-12-01

Wildfire frequency in the southern Sierra Nevada has increased over the past decades. The effects of wildfires on soils can increase the frequency of slope failure and debris flow events, which pose a greater risk to people, as human populations expand into foothill and mountainous communities of the Sierra Nevada. Alterations in the physical properties of burned soils are one such effect that can catalyze slope failure and debris flow events. Moreover, the degree of a soil's physical alteration resulting from wildfire is linked to fire intensity. The 2016 Erskine fire occurred in the southern Sierra Nevada, burning 48,019 acres, resulting in soils of unburned, low, moderate, and high burn severities. In this study, the physical properties of soils with varying degrees of burn severity are explored within the 2016 Erskine fire perimeter. The results constrain the effects of burn severity on soil's physical properties. Unburned, low, moderate, and high burn severity soil samples were collected within the Erskine fire perimeter. Alterations in soils' physical properties resulting from burn severity are explored using X-ray diffractometry analysis, liquid limit, plastic limit, and shear strength tests. Preliminary results from this study will be used to assess debris flow and slope failure hazard models within burned areas of the Kern River watershed in the southern Sierra Nevada.

Smouldering Fires in the Earth System

NASA Astrophysics Data System (ADS)

Rein, G.

2012-04-01

Smouldering fires, the slow, low-temperature, flameless burning, represent the most persistent type of combustion phenomena and the longest continuously fires on Earth system. Indeed, smouldering mega-fires of peatlands occur with some frequency during the dry session in, for example, Indonesia, Canada, Russia, UK and USA. Smouldering fires propagate slowly through organic layers of the ground and can reach depth >5 m if large cracks, natural piping or channel systems exist. It threatens to release sequestered carbon deep into the soil. Once ignited, they are particularly difficult to extinguish despite extensive rains, weather changes or fire-fighting attempts, and can persist for long periods of time (months, years) spreading deep and over extensive areas. Recent figures at the global scale estimate that average annual greenhouse gas emissions from smouldering fires are equivalent to 15% of man-made emissions. These fires are difficult or impossible to detect with current remote sensing methods because the chemistry is significantly different, their thermal radiation signature is much smaller, and the plume is much less buoyant. These wildfires burn fossil fuels and thus are a carbon-positive fire phenomena. This creates feedbacks in the climate system because soil moisture deficit and self-heating are enchanted under warmer climate scenarios and lead to more frequent fires. Warmer temperatures at high latitudes are resulting in more frequent Artic fires. Unprecedented permafrost thaw is leaving large soil carbon pools exposed to smouldering fires for the fist time since millennia. Although interactions between flaming fires and the Earth system have been a central focus, smouldering fires are as important but have received very little attention. DBut differences with flaming fires are important. This paper reviews the current knowledge on smouldering fires in the Earth system regarding combustion dynamics, damage to the soil, emissions, remote sensing and feedbacks in the climate system.

Biochar for soil fertility and natural carbon sequestration

USGS Publications Warehouse

Rostad, C.E.; Rutherford, D.W.

2011-01-01

Biochar is charcoal (similar to chars generated by forest fires) that is made for incorporation into soils to increase soil fertility while providing natural carbon sequestration. The incorporation of biochar into soils can preserve and enrich soils and also slow the rate at which climate change is affecting our planet. Studies on biochar, such as those cited by this report, are applicable to both fire science and soil science.

Contents and leachability of heavy metals (Pb, Cu, Sb, Zn, As) in soil at the Pantex firing range, Amarillo, Texas.

PubMed

Basunia, S; Landsberger, S

2001-10-01

Pantex firing range soil samples were analyzed for Pb, Cu, Sb, Zn, and As. One hundred ninety-seven samples were collected from the firing range and vicinity area. There was a lack of knowledge about the distribution of Pb in the firing range, so a random sampling with proportional allocation was chosen. Concentration levels of Pb and Cu in the firing range were found to be in the range of 11-4675 and 13-359 mg/kg, respectively. Concentration levels of Sb were found to be in the range of 1-517 mg/kg. However, the Zn and As concentration levels were close to average soil background levels. The Sn concentration level was expected to be higher in the Pantex firing range soil samples. However, it was found to be below the neutron activation analysis (NAA) detection limit of 75 mg/kg. Enrichment factor analysis showed that Pb and Sb were highly enriched in the firing range with average magnitudes of 55 and 90, respectively. Cu was enriched approximately 6 times more than the usual soil concentration levels. Toxicity characteristic leaching procedure (TCLP) was carried out on size-fractionated homogeneous soil samples. The concentration levels of Pb in leachates were found to be approximately 12 times higher than the U.S. Environmental Protection Agency (EPA) regulatory concentration level of 5 mg/L. Sequential extraction (SE) was also performed to characterize Pb and other trace elements into five different fractions. The highest Pb fraction was found with organic matter in the soil.

Fire impact on forest soils evaluated using near-infrared spectroscopy and multivariate calibration.

PubMed

Vergnoux, A; Dupuy, N; Guiliano, M; Vennetier, M; Théraulaz, F; Doumenq, P

2009-11-15

The assessment of physico-chemical properties in forest soils affected by fires was evaluated using near infrared reflectance (NIR) spectroscopy coupled with chemometric methods. In order to describe the soil properties, measurements were taken of the total organic carbon on solid phase, the total nitrogen content, the organic carbon and the specific absorbences at 254 and 280 nm of humic substances, organic carbon in humic and fulvic acids, concentrations of NH(4)(+), Ca(2+), Mg(2+), K(+) and phosphorus in addition to NIR spectra. Then, a fire recurrence index was defined and calculated according to the different fires extents affecting soils. This calculation includes the occurrence of fires as well as the time elapsed since the last fire. This study shows that NIR spectroscopy could be considered as a tool for soil monitoring, particularly for the quantitative prediction of the total organic carbon, total nitrogen content, organic carbon in humic substances, concentrations of phosphorus, Mg(2+), Ca(2+) and NH(4)(+) and humic substances UVSA(254). Further validation in this field is necessary however, to try and make successful predictions of K(+), organic carbon in humic and fulvic acids and the humic substances UVSA(280). Moreover, NIR coupled with PLS can also be useful to predict the fire recurrence index in order to determine the spatial variability. Also this method can be used to map more or less burned areas and possibly to apply adequate rehabilitation techniques, like soil litter reconstitution with organic enrichments (industrial composts) or reforestation. Finally, the proposed recurrence index can be considered representative of the state of the soils.

Impact of fire on active layer and permafrost microbial communities and metagenomes in an upland Alaskan boreal forest.

PubMed

Taş, Neslihan; Prestat, Emmanuel; McFarland, Jack W; Wickland, Kimberley P; Knight, Rob; Berhe, Asmeret Asefaw; Jorgenson, Torre; Waldrop, Mark P; Jansson, Janet K

2014-09-01

Permafrost soils are large reservoirs of potentially labile carbon (C). Understanding the dynamics of C release from these soils requires us to account for the impact of wildfires, which are increasing in frequency as the climate changes. Boreal wildfires contribute to global emission of greenhouse gases (GHG-CO2, CH4 and N2O) and indirectly result in the thawing of near-surface permafrost. In this study, we aimed to define the impact of fire on soil microbial communities and metabolic potential for GHG fluxes in samples collected up to 1 m depth from an upland black spruce forest near Nome Creek, Alaska. We measured geochemistry, GHG fluxes, potential soil enzyme activities and microbial community structure via 16SrRNA gene and metagenome sequencing. We found that soil moisture, C content and the potential for respiration were reduced by fire, as were microbial community diversity and metabolic potential. There were shifts in dominance of several microbial community members, including a higher abundance of candidate phylum AD3 after fire. The metagenome data showed that fire had a pervasive impact on genes involved in carbohydrate metabolism, methanogenesis and the nitrogen cycle. Although fire resulted in an immediate release of CO2 from surface soils, our results suggest that the potential for emission of GHG was ultimately reduced at all soil depths over the longer term. Because of the size of the permafrost C reservoir, these results are crucial for understanding whether fire produces a positive or negative feedback loop contributing to the global C cycle.

Impact of fire on active layer and permafrost microbial communities and metagenomes in an upland Alaskan boreal forest

PubMed Central

Taş, Neslihan; Prestat, Emmanuel; McFarland, Jack W; Wickland, Kimberley P; Knight, Rob; Berhe, Asmeret Asefaw; Jorgenson, Torre; Waldrop, Mark P; Jansson, Janet K

2014-01-01

Permafrost soils are large reservoirs of potentially labile carbon (C). Understanding the dynamics of C release from these soils requires us to account for the impact of wildfires, which are increasing in frequency as the climate changes. Boreal wildfires contribute to global emission of greenhouse gases (GHG—CO2, CH4 and N2O) and indirectly result in the thawing of near-surface permafrost. In this study, we aimed to define the impact of fire on soil microbial communities and metabolic potential for GHG fluxes in samples collected up to 1 m depth from an upland black spruce forest near Nome Creek, Alaska. We measured geochemistry, GHG fluxes, potential soil enzyme activities and microbial community structure via 16SrRNA gene and metagenome sequencing. We found that soil moisture, C content and the potential for respiration were reduced by fire, as were microbial community diversity and metabolic potential. There were shifts in dominance of several microbial community members, including a higher abundance of candidate phylum AD3 after fire. The metagenome data showed that fire had a pervasive impact on genes involved in carbohydrate metabolism, methanogenesis and the nitrogen cycle. Although fire resulted in an immediate release of CO2 from surface soils, our results suggest that the potential for emission of GHG was ultimately reduced at all soil depths over the longer term. Because of the size of the permafrost C reservoir, these results are crucial for understanding whether fire produces a positive or negative feedback loop contributing to the global C cycle. PMID:24722629

Medium-long term soil resilience against different disturbances: wildfires, silvicultural treatments and climate change

NASA Astrophysics Data System (ADS)

Hedo de Santiago, Javier; Borja, Manuel Esteban Lucas; de las Heras, Jorge

2016-04-01

Soils of semiarid Mediterranean forest ecosystems are very fragile and sensitive to changes due to different anthropogenic and natural disturbances. The increasing vulnerability of semiarid lands within this world framework has generated growing awareness in the field of research, with highly intensified study into soils properties. One of the main problems of Mediterranean forests is wildfire disturbance. Fire should be considered more an ecological factor but, in contrast to the role of fire, it is now a closely related factor to human action. On the other hand, to improve the recovery of forest communities after fire, silvicultural treatments are needed and, for that matter, another disturbance is added to the ecosystem. By last, climate change is also affecting the fire regime increasing fire frequency and burned area, enhancing the destructiveness to Mediterranean ecosystems. After all of these three disturbances, changes in vegetation dynamics and soil properties are expected to occur due to the plant-soil feedback. Soil plays an essential role in the forest ecosystem's fertility and stability and specifically soil microorganisms, which accomplish reactions to release soil nutrients for vegetation development, for that is essential to enlarge knowledge about soil properties resilience in semiarid forest ecosystems. Physico-chemical and microbiological soil properties, and enzyme activities have been studied in two Aleppo pine forest stands that have suffered three disturbances: 1) a wildfire event, 2) silvicultural treatments (thinning) and 3) an artificial drought (simulating climate change) and results showed that soil recovered after 15 years. Final results showed that soils have been recovered from the three disturbances at the medium-long term.

Carbon loss from an unprecedented Arctic tundra wildfire.

PubMed

Mack, Michelle C; Bret-Harte, M Syndonia; Hollingsworth, Teresa N; Jandt, Randi R; Schuur, Edward A G; Shaver, Gaius R; Verbyla, David L

2011-07-27

Arctic tundra soils store large amounts of carbon (C) in organic soil layers hundreds to thousands of years old that insulate, and in some cases maintain, permafrost soils. Fire has been largely absent from most of this biome since the early Holocene epoch, but its frequency and extent are increasing, probably in response to climate warming. The effect of fires on the C balance of tundra landscapes, however, remains largely unknown. The Anaktuvuk River fire in 2007 burned 1,039 square kilometres of Alaska's Arctic slope, making it the largest fire on record for the tundra biome and doubling the cumulative area burned since 1950 (ref. 5). Here we report that tundra ecosystems lost 2,016 ± 435 g C m(-2) in the fire, an amount two orders of magnitude larger than annual net C exchange in undisturbed tundra. Sixty per cent of this C loss was from soil organic matter, and radiocarbon dating of residual soil layers revealed that the maximum age of soil C lost was 50 years. Scaled to the entire burned area, the fire released approximately 2.1 teragrams of C to the atmosphere, an amount similar in magnitude to the annual net C sink for the entire Arctic tundra biome averaged over the last quarter of the twentieth century. The magnitude of ecosystem C lost by fire, relative to both ecosystem and biome-scale fluxes, demonstrates that a climate-driven increase in tundra fire disturbance may represent a positive feedback, potentially offsetting Arctic greening and influencing the net C balance of the tundra biome.

Does fire severity influence shrub resprouting after spring prescribed burning?

NASA Astrophysics Data System (ADS)

Fernández, Cristina; Vega, José A.; Fonturbel, Teresa

2013-04-01

Prescribed burning is commonly used to reduce the risk of severe wildfire. However, further information about the associated environmental effects is required to help forest managers select the most appropriate treatment. To address this question, we evaluated if fire severity during spring prescribed burning significantly affects the resprouting ability of two common shrub species in shrubland under a Mediterranean climate in NW Spain. Fire behaviour and temperatures were recorded in tagged individuals of Erica australis and Pterospartum tridentatum during prescribed burning. The number and length of resprouted shoots were measured three times (6, 12 and 18 months) after the prescribed burning. The influence of a series of fire severity indicators on some plant resprouting vigour parameters was tested by canonical correlation analysis. Six months and one year after prescribed burning, soil burn severity (measured by the absolute reduction in depth of the organic soil layer, maximum temperatures in the organic soil layer and the mineral soil surface during burning and the post-fire depth of the organic soil layer) reduced the resprouting vigour of E. australis and P. tridentatum. In contrast, direct measurements of fire effects on plants (minimum branch diameter, duration of temperatures above 300 °C in the shrub crown and fireline intensity) did not affect the post-fire plant vigour. Soil burn severity during spring prescribed burning significantly affected the short-term resprouting vigour in a mixed heathland in Galicia. The lack of effects eighteen months after prescribed burning indicates the high resilience of these species and illustrates the need to conciliate fire prevention and conservation goals.

Water repellency, plants, agriculture abandonment and fire in citrus plantations. The Canyoles river watershed study site

NASA Astrophysics Data System (ADS)

Cerdà, Artemi; Jordán, Antonio; Doerr, Stefan Helmut

2017-04-01

Soil water repellency (SWR) is a key soil property that determine the soil and water losses, soil fertility and plant development. Although until the 90's the soil water repellency was seeing as an uncommon soil characteristic, now is considered a key soil property to understand the soil hydrology (Alanís et al., 2016; Hewelke et al., 2016; Keesstra et al., 2016; Jiménez-Morillo et al., 2016). The inspiring research of Leonard DeBano and Stefan H Doerr changed the fate of the science (DeBano, 2000; Doerr et al. 2000). Soil water repellency was associated to forest fire affected land due to the pioneer contribution of professor DeBano in the 70's and Professor Doerr in the 90's. The research during the last two decades demonstrate that fire affects the reallocation of the hydrophobic substances and can reduce or increase the severity of the soil water repellence at different soil depths and horizons. The SWR is usually measured by sampling to show the influence of key soil properties (texture, structure, plant cover, litter, season…) on the degree of soil water repellency. The sampling is applied usually with a few drops when the Water Drop Penetration Time method is applied, and this inform of the time of penetration, but few researches focussed in the spatial distribution of the water repellency, which is a key factor of the runoff generation, the water infiltration and the water redistribution such as demonstrate the wetting fronts. Our approach research the spatial distribution of the water repellency by means of an intense sampling of soil surface water repellency. One thousand drops were distributed in a square meter (100 lines separated 1 cm and 100 drops per each line of 100 cm, with a total od 1000 drops in 1m2) on 10 sampling points on 4 land managements: ploughing and herbicide agriculture fields treatment), abandoned 10 years, and burnt. The research was carried out in citrus plantations of the Canyoles river watershed. The results show that the agriculture soil managed with tillage is hydrophilic, that the use of herbicides trigger a patchy and slight presence of hydrophobicity, that the growth of vegetation reached the highest water repellency degree with a patch distribution of the water repellency, and finally the fire reduced the surface water repellency and changes the spatial pattern. This study aims to fulfil the gap of a sampling strategy that will help the scientist to characterize the soil water repellency with a uniform and standard procedure and protocol. The results show the importance of the management to control the soil repellency (Bodí et al., 2012a) and the importance of the fire and ash and the water repellency (Bodí et al., 2012b; Dlapa et al., 2013; Benito Rueda et al., 2016). Acknowledgements The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n[U+25E6] 603498 (RECARE project) and the CGL2013- 47862-C2-1-R and CGL2016-75178-C2-2-R national research projects. References Alanís, N., Hernández-Madrigal, V. M., Cerdà, A., Muñoz-Rojas, M., Zavala, L. M., & Jordán, A. (2016). Spatial gradients of intensity and persistence of soil water repellency under different forest types in central mexico. Land Degradation and Development, doi:10.1002/ldr.2544 Benito Rueda, E., M. Rodríguez-Alleres, and E. Varela Teijeiro. 2016. Environmental Factors Governing Soil Water Repellency Dynamics in a Pinus Pinaster Plantation in NW Spain. Land Degradation and Development 27 (3): 719-728. doi:10.1002/ldr.2370. Bodí, M. B., A. Cerdà, J. Mataix-Solera, and S. H. Doerr. 2012a. Water Repellency in Forest Soils Affected by Fires and Agricultural Soils with Different Agricultural Management and Abandonment. Cuadernos De Investigacion Geografica 38 (2): 53-74. Bodí, M. B., S. H. Doerr, A. Cerdà, and J. Mataix-Solera. 2012b. Hydrological Effects of a Layer of Vegetation Ash on Underlying Wettable and Water Repellent Soil. Geoderma 191: 14-23. doi:10.1016/j.geoderma.2012.01.006. DeBano, L.F, 2000. The role of fire and soil heating on water repellency in wildland environments: a review. Journal of Hydrology 231, 195-206. Dlapa, P., M. B. Bodí, J. Mataix-Solera, A. Cerdà, and S. H. Doerr. 2013. FT-IR Spectroscopy Reveals that Ash Water Repellency is Highly Dependent on Ash Chemical Composition. Catena 108: 35-43. doi:10.1016/j.catena.2012.02.011. Doerr, S.H., Shakesby, R.A., and Walsh, R.P.D., 2000. Soil water repellency: its causes, characteristics and hydro-geomorphological significance. Earth-Science Reviews, 51 (1), 33-65. Hewelke, E., Szatylowicz, J., Gnatowski, T., & Oleszczuk, R. (2016). Effects of soil water repellency on moisture patterns in a degraded sapric histosol. Land Degradation and Development, 27(4), 955-964. doi:10.1002/ldr.2305 Jiménez-Morillo, N. T., González-Pérez, J. A., Jordán, A., Zavala, L. M., de la Rosa, J. M., Jiménez-González, M. A., & González-Vila, F. J. (2016). Organic matter fractions controlling soil water repellency in sandy soils from the doñana national park (southwestern spain). Land Degradation and Development, 27(5), 1413-1423. doi:10.1002/ldr.2314 Keesstra, S., Wittenberg, L., Maroulis, J., Sambalino, F., Malkinson, D., Cerdà, A., & Pereira, P. (2017). The influence of fire history, plant species and post-fire management on soil water repellency in a mediterranean catchment: The mount carmel range, israel. Catena, 149, 857-866. doi:10.1016/j.catena.2016.04.006

Influence of disturbance on temperate forest productivity

USGS Publications Warehouse

Peters, Emily B.; Wythers, Kirk R.; Bradford, John B.; Reich, Peter B.

2013-01-01

Climate, tree species traits, and soil fertility are key controls on forest productivity. However, in most forest ecosystems, natural and human disturbances, such as wind throw, fire, and harvest, can also exert important and lasting direct and indirect influence over productivity. We used an ecosystem model, PnET-CN, to examine how disturbance type, intensity, and frequency influence net primary production (NPP) across a range of forest types from Minnesota and Wisconsin, USA. We assessed the importance of past disturbances on NPP, net N mineralization, foliar N, and leaf area index at 107 forest stands of differing types (aspen, jack pine, northern hardwood, black spruce) and disturbance history (fire, harvest) by comparing model simulations with observations. The model reasonably predicted differences among forest types in productivity, foliar N, leaf area index, and net N mineralization. Model simulations that included past disturbances minimally improved predictions compared to simulations without disturbance, suggesting the legacy of past disturbances played a minor role in influencing current forest productivity rates. Modeled NPP was more sensitive to the intensity of soil removal during a disturbance than the fraction of stand mortality or wood removal. Increasing crown fire frequency resulted in lower NPP, particularly for conifer forest types with longer leaf life spans and longer recovery times. These findings suggest that, over long time periods, moderate frequency disturbances are a relatively less important control on productivity than climate, soil, and species traits.

Forest soil erosion prediction as influenced by wildfire and roads

NASA Astrophysics Data System (ADS)

Cao, L.; Brooks, E. S.; Elliot, W.

2017-12-01

Following a wildfire, the risk of erosion is greatly increased. Forest road networks may change the underlying topography and alter natural flow paths. Flow accumulation and energy can be redistributed by roads and alter soil erosion processes. A LiDAR (Light Detection and Ranging) DEM makes it possible to quantify road topography, and estimate how roads influence surface runoff and sediment transport in a fire-disturbed watershed. With GIS technology and a soil erosion model, this study was carried out to evaluate the effect of roads on erosion and sediment yield following the Emerald Fire southwest of Lake Tahoe. The GeoWEPP model was used to estimate onsite erosion and offsite sediment delivery from each hillslope polygon and channel segment before and after fire disturbance in part of the burned area. The GeoWEPP flow path method was used to estimate the post-fire erosion rate of each GIS pixel. A 2-m resolution LiDAR DEM was used as the terrain layer. The Emerald Fire greatly increased onsite soil loss and sediment yields within the fire boundary. Following the fire, 78.71% of the burned area had predicted sediment yields greater than 4 Mg/ha/yr, compared to the preburn condition when 65.3% of the study area was estimated to generate a sediment yield less than 0.25 Mg/ha/yr. Roads had a remarkable influence on the flow path simulation and sub-catchments delineation, affecting sediment transport process spatially. Road segments acted as barriers that intercepted overland runoff and reduced downslope flow energy accumulation, therefore reducing onsite soil loss downslope of the road. Roads also changed the boundary of sub-catchment and defined new hydrological units. Road segments can transport sediment from one sub-catchment to another. This in turn leads to the redistribution of sediment and alters sediment yield for some sub-catchments. Culverts and road drain systems are of vital importance in rerouting runoff and sediment. Conservation structures can be installed to avoid sediment deposition or debris accumulation on the road surface. On the other hand, the outlets of culverts might be at a high risk of increasing downstream channel erosion due to the large amount of runoff. This implies that conservation measurements should be considered to control the runoff and sediment output from culverts.

Amazon rain-forest fires.

PubMed

Sanford, R L; Saldarriaga, J; Clark, K E; Uhl, C; Herrera, R

1985-01-04

Charcoal is common in the soils of mature rain forests within 75 kilometers of San Carlos de Rio Negro in the north central Amazon Basin. Carbon-14 dates of soil charcoal from this region indicate that numerous fires have occurred since the mid-Holocene epoch. Charcoal is most common in tierra firme forest Oxisols and Ultisols and less common in caatinga and igapo forest soils. Climatic changes or human activities, or both, have caused rain-forest fires.

A dynamic organic soil biogeochemical model for simulating the effects of wildfire on soil environmental conditions and carbon dynamics of black spruce forests

Treesearch

Shuhua Yi; A. David McGuire; Eric Kasischke; Jennifer Harden; Kristen Manies; Michelle Mack; Merritt Turetsky

2010-01-01

Ecosystem models have not comprehensively considered how interactions among fire disturbance, soil environmental conditions, and biogeochemical processes affect ecosystem dynamics in boreal forest ecosystems. In this study, we implemented a dynamic organic soil structure in the Terrestrial Ecosystem Model (DOS-TEM) to investigate the effects of fire on soil temperature...

Evaluation of post fire changes in soil properties and influence on the hydrological and erosive dynamics in a Mediterranean watershed

NASA Astrophysics Data System (ADS)

Sanz, Inés; Aguilar, Cristina; Millares, Agustín

2013-04-01

In the last fifty years, forest fires and changes in land use and management practices have had a significant influenceon the evolution of soil loss processes in the Mediterranean area. Forest fires have immediate effects in hydrological processes mainly due to sudden changes in soil properties and vegetation cover. After a fire there is an increase in runoff processes and peak flows and thus in the amount and composition of the sediments produced. Silting in dams downstream is often reported so the description of the post-fire hydrological processes is crucial in order to optimize decision making. This study analyzes a micro-watershed of 25 ha in the south of Spain that suffered a fire in October 2010 burning around a 2 km2 area. As the erosive processes in this area are directly related to concentrated overland flow, an indirect assessment of soil loss is presented in this work based on evaluating changes in runoff in Mediterranean post-fire situations. For this, the study is divided into two main parts. Firstly, changes in soil properties and vegetation cover are evaluated. Secondly, the effects of these changes in the hydrological and erosive dynamics are assessed.The watershed had been monitored in previous studies so soil properties and the vegetation cover before the fire took place were already characterized. Besides, the hydrological response was also available through an already calibrated and validated physically-based distributed hydrological model. For the evaluation of soil properties, field measurement campaigns were designed. Philip Dunne's tests for the determination of saturated hydraulic conductivity, as well as moisture content and bulk density measurements were carried out in both unaltered and burned soil samples. Changes in the vegetation cover fraction were assessed through desktop analysis of Landsat-TM5 platform satellite images as well as through visual inspection in the field campaigns. The analysis of the hydraulic conductivity revealed a reduction in post-fire values of near 90 % over those previous to the fire. Regarding the vegetation cover, the recovery of the burned covers, mainly herbaceous with some bushes, turned out to quick due to the wet character of the year. Nevertheless, an apparent decrease in the cover fraction and thus in the vegetation storage capacity was reported. These changes were incorporated into a new hydrological model configuration and compared to the response previous to the fire. The results point out the rainfall pattern to be a determinant factor in post-fire situation with an increase in modeled runoff of up to 350% and even more in dry years. These results have direct implications in soil erodibility changes in hillslopes as well as a considerable increase in bedload processes in Mediterranean alluvial rivers.

The Role of Disturbance in Arctic Ecosystem Response to a Changing Climate

NASA Astrophysics Data System (ADS)

Hinzman, L. D.

2014-12-01

Wildfires in the tundra regions and the boreal forest project an immediate effect upon the surface energy and water budget by drastically altering the surface albedo, roughness, infiltration rates, and moisture absorption capacity in organic soils. Although fires create a sudden and drastic change to the landcover, it is only the beginning of a long process of recovery and perhaps a shift to a different successional pathway. In permafrost regions, these effects become part of a process of long-term (20-50 years) cumulative impacts. Burn severity may largely determine immediate impacts and long-term disturbance trajectories. As transpiration decreases or ceases, soil moisture increases markedly, remaining quite wet throughout the year. Because the insulating quality of the organic layer is removed during fires, permafrost begins to thaw near the surface and warm to greater depths. Within a few years, it may thaw to the point where it can no longer completely refreeze every winter, creating a permanently thawed layer in the soil called a talik. After formation of a talik, soils can drain internally throughout the year. At this point, soils may become quite dry, as the total precipitation received annually in the Arctic is quite low. The local ecological community must continuously adapt to the changing soil thermal and moisture regimes. The wet soils found over shallow permafrost favor black spruce forests. After a fire creates a deeper permafrost table (thicker active layer) the invading tree species tend to be birch or alder. The hydrologic and thermal regime of the soil is the primary factor controlling these vegetation trajectories and the subsequent changes in surface mass and energy fluxes. The complexities of a changing climate accentuate these processes of change and complicate predictions of the resulting vegetation trajectories. Understanding these shifts in vegetative communities and quantifying the consequences of thawing permafrost can only be accomplished through complementary analyses of field research data and numerical simulations. The permafrost dramatically controls other landscape features and its dynamic response to thermal influences yield consequent effects on the surficial ecology, water and energy balances and regional climate.

Soil heating during wildfires and prescribed burns: a global evaluation based on existing and new data

NASA Astrophysics Data System (ADS)

Doerr, Stefan; Santin, Cristina; Reardon, James; Mataix-Solera, Jorge; Stoof, Cathelijne; Bryant, Rob; Miesel, Jessica; Badia, David

2017-04-01

Heat transfer from the combustion of ground fuels and soil organic matter during vegetation fires can cause substantial changes to the physical, chemical and biological characteristics of soils. Numerous studies have investigated the effects of wildfires and prescribed burns on soil properties based either on field samples or using laboratory experiments. Critical thresholds for changes in soil properties, however, have been determined largely based on laboratory heating experimentation. These experimental approaches have been criticized for being inadequate for reflecting the actual heating patterns soil experienced in vegetation fires, which remain poorly understood. To address this research gap, this study reviews existing and evaluates new field data on key soil heating parameters determined during wildfires and prescribed burns from a wide range of environments. The results highlight the high spatial and temporal variability in soil heating patters not only between, but also within fires. Most wildfires and prescribed burns are associated with heat pulses that are much shorter than those typically applied in laboratory studies, which can lead to erroneous conclusions when results from laboratory studies are used to predict fire impacts on soils in the field.

The effect of fire and permafrost interactions on soil carbon accumulation in an upland black spruce ecosystem of interior Alaska: Implications for post-thaw carbon loss

USGS Publications Warehouse

O'Donnell, J. A.; Harden, J.W.; McGuire, A.D.; Kanevskiy, M.Z.; Jorgenson, M.T.; Xu, X.

2011-01-01

High-latitude regions store large amounts of organic carbon (OC) in active-layer soils and permafrost, accounting for nearly half of the global belowground OC pool. In the boreal region, recent warming has promoted changes in the fire regime, which may exacerbate rates of permafrost thaw and alter soil OC dynamics in both organic and mineral soil. We examined how interactions between fire and permafrost govern rates of soil OC accumulation in organic horizons, mineral soil of the active layer, and near-surface permafrost in a black spruce ecosystem of interior Alaska. To estimate OC accumulation rates, we used chronosequence, radiocarbon, and modeling approaches. We also developed a simple model to track long-term changes in soil OC stocks over past fire cycles and to evaluate the response of OC stocks to future changes in the fire regime. Our chronosequence and radiocarbon data indicate that OC turnover varies with soil depth, with fastest turnover occurring in shallow organic horizons (~60 years) and slowest turnover in near-surface permafrost (>3000 years). Modeling analysis indicates that OC accumulation in organic horizons was strongly governed by carbon losses via combustion and burial of charred remains in deep organic horizons. OC accumulation in mineral soil was influenced by active layer depth, which determined the proportion of mineral OC in a thawed or frozen state and thus, determined loss rates via decomposition. Our model results suggest that future changes in fire regime will result in substantial reductions in OC stocks, largely from the deep organic horizon. Additional OC losses will result from fire-induced thawing of near-surface permafrost. From these findings, we conclude that the vulnerability of deep OC stocks to future warming is closely linked to the sensitivity of permafrost to wildfire disturbance. ?? 2010 Blackwell Publishing Ltd.

Long term effects of fire on carbon and nitrogen pools and fluxes in the arctic permafrost and subarctic forests (ARCTICFIRE)

NASA Astrophysics Data System (ADS)

Pumpanen, Jukka; Köster, Kajar; Aaltonen, Heidi; Köster, Egle; Zhou, Xuan; Zhang-Turpeinen, Huizhong; Heinonsalo, Jussi; Palviainen, Marjo; Sun, Hui; Biasi, Christina; Bruckman, Viktor; Prokushkin, Anatoly; Berninger, Frank

2017-04-01

Boreal forests, which are to a large extent located on permafrost soils, are a crucial part of the climate system because of their large soil carbon (C) pool. Even small change in this pool may change the terrestrial C sink in the arctic into a source with a consequent increase in CO2 concentrations. About 1% of boreal forests are exposed to fire annually, which affects the soil and permafrost under them. Thawing of permafrost increases the depth of the active layer containing large C and N stocks. In addition to temperature, the decomposition of soil organic matter depends on its chemical composition which may also be affected by fires. Part of the soil organic matter is turned into pyrogenic C and N resistant to decomposition. We studied the effect of forest fires on soil greenhouse gas fluxes (CO2, CH4 and N2O)and biogenic volatile organic compound fluxes using portable chambers. The amount of easily decomposable and recalcitrant fractions in soil organic matter were determined with water, ethanol and acid extraction, and the natural 13C and 15N abundances as well as chemical quality with Fourier Transform Infrared Spectroscopy (FTIR) were studied. Also, changes in microbial community structure and composition were analyzed with next generation pyrosequencing. Our preliminary results indicate that soil CO2 effluxes were significantly decreased immediately after the fire, and the recovery to pre-fire level took several decades. Soils were a small sink of CH4 and a source of N2O in all age classes, and the CH4 uptake was increased and N2O fluxes decreased still 20 years following the fire. A clear vertical distribution was observed in the amount of extractable soil organic matter the amount of extractable organic matter being highest in the soil surface layers and decreasing with depth. The natural 13C and 15N abundances and FTIR spectra and changes in microbial community composition are still under analysis.

Development of new index for forest fire risk using satellite images in Indonesia through the direct spectral measurements of soil

NASA Astrophysics Data System (ADS)

Hashimoto, A.; Akita, M.; Takahashi, Y.; Suzuki, H.; Hasegawa, Y.; Ogino, Y.; Naruse, N.; Takahashi, Y.

2016-12-01

In recent years, the smoke caused by the forest fires in Indonesia has become a serious problem. Most of the land in Indonesia is covered with peat moss, which occurs the expanding of fires due to the burning itself. Thus, the surface soil water, reflecting the amount of precipitation in the area, can become the indication of the risk of fires. This study aims to develop a new index reflecting the risk of forest fires in Indonesia using satellite remote sensing through the direct spectral measurements of peat moss soil.We have prepared the peat moss in 7 steps of soil water content measured at an accuracy of ±15 percent (Field pro, WD-3). We obtained spectra between 400nm and 1050nm (Source: halogen lamp, spectroscope: self-made space time, spectral analysis kit) from the peat moss.The obtained spectra show the difference from the previous spectral measurement for the soil in various water content. There are the features, especially, in the wavelength range of ultraviolet (400-450nm) and infrared (530-800nm) as shown in the figure; the more the soil water increases, the lower the reflectance becomes. We have developed a new index using the New deep blue band (433 453nm and NIR band 845 885nm of Landsat 8. The resulting satellite images calculated by our original index appears to reflect the risk of forest fires rather than well-known indices such as Normalized Difference Water Index and Normalized difference Soil Index.In conclusion, we have created a new index that highly reflects to the degree of soil water of a peat soil in Indonesia.

Temporal fluctuations in soil water repellency following wildfire in chaparral steeplands, southern California

Treesearch

K.R. Hubbert; V. Oriol

2005-01-01

Soil water repellency is partularly common in unburned chaparral, and its degree and duration can be influenced by seasonal weather conditions. Water repellency tends to increase in dry soils, whil eit decreases or vanishes following precipitation or extended periods of soil moisture. The 15426 ha Williams Fire provided an opportunity to investigate post-fire...

Phytoextraction of lead from firing range soils with Vetiver grass

Treesearch

E. W. Wilde; R. L. Brigmon; D. L. Dunn; M. A. Heitkamp; D. C. Dagnan

2007-01-01

Vetiver grass (Vetiveria zizanoides) along with soil amendments were evaluated for phytoextraction of lead and other metals (zinc, copper, and iron) from the soil of an active firing range at the Savannah River Site, SC. Lead-contaminated soil (300-4,500 ppm/kg) was collected, dried, placed in pots, fertilized, and used as a medium for growing...

Prescribed fire, soil nitrogen dynamics, and plant responses in a semiarid grassland

USDA-ARS?s Scientific Manuscript database

Fire is a key driver of the structure and function of grassland ecosystems. In arid and semiarid ecosystems, where moisture limits plant production more than light, fire can potentially affect ecosystem dynamics through changes in soil moisture, temperature, and nitrogen cycling, as well as through ...

Augmentation of freeze-thaw cycles in the alpine soil triggered by the fire on the alpine slopes, Mount Shirouma-dake, northern Japanese Alps

NASA Astrophysics Data System (ADS)

Sasaki, A.; Suzuki, K.

2015-12-01

This is the continuous study to clarify the geo-environmental changes on the post-fire alpine slopes of Mount Shirouma-dake in the northern Japanese Alps. The fire occurred at May 9, 2009 on the alpine slopes of Mount Shirouma-dake, and the fire spread to the Pinus pumila communities and grasslands. Although the grass had a little damage by the fire, the P. pumila received nearly impact of the fire. In the P. pumila communities where the leaf burnt, forest floor is exposed and become easy to be affected by atmospheric condition such as rain, wind, snow, and etc. First, we illustrated a map of micro-landforms, based on geomorphological fieldworks. We observed these micro-landforms repeatedly for fifth years after the fire. As the results of the observation, it is clear that remarkable changes of these micro-landforms have not occurred but some litters on the forest-floor in the P. pumila communities are flushed out to surroundings. The litter layer on the forest-floor in the P. pumila communities were 3-4 cm thick in August of 2011, but it became 0.5 cm thick in September of 2014. The P. pumila communities established on the slopes consists of angular and sub-angular gravel with openwork texture, which are covered by thin soil layer. Therefore, it is necessary to pay attention to soil erosion following the outflow of the litter. In addition, we observe the ground temperature and soil moisture, under the fired P. pumila communities and the no fired P. pumila communities after the fire, to find influence of the fire. The ground temperature sensors were installed into at 1 cm, 10 cm, and 40 cm depth. The soil moisture sensors were installed into at 1 cm and 10 cm depth. The 1 cm depth of the soil on the post-fire slopes, diurnal freeze-thaw cycles occurred in October and November of 2011, 2012, 2013, and 2014 but it had not occurred in 2009 and 2010. In addition, the period of seasonal frost at 10 cm and 40 cm depth on the post-fire slopes are extended for two weeks. These thermal condition changes are triggered by decrease in the thickness of the litter layer on the fired P. pumila communities.

Biochemical resistance of pyrogenic organic matter in fire-affected mineral soils of Southern Europe

NASA Astrophysics Data System (ADS)

Knicker, H.; González Vila, F. J.; Clemente Salas, L.

2012-04-01

Incorporated into the soil, naturally formed pyrogenic organic matter (PyOM) is considered as highly recalcitrant, but direct estimation of PyOM decomposition rates are scarce. With this aim in mind, we subjected organic matter (OM) of fire-affected and unaffected soils to biochemical degradation under laboratory conditions and monitored CO2 production over a period of seven months. The soils derived from fire affected and unaffected areas of the Sierra de Aznalcóllar and the Doñana National Park, Southern Spain. Virtual fractionation of the solid-state 13C nuclear magnetic resonance (NMR) spectra of the fire affected soils into fire-unaffected soil organic matter (SOM) and PyOM yielded charcoal C contributions of 30 to 50% to the total organic C (Corg) of the sample derived from the Aznalcóllar region. Fitting the respiration data with a double exponential decay model revealed a fast carbon flush during the first three weeks of the experiment. Solid-state 13C NMR spectroscopy evidenced the contribution of aromatic moieties of the PyOM to this initial carbon release and to the biosynthesis of new microbial biomass. The input of PyOM resulted in an increase of the mean residence time (MRT) of the slow OM pool of the soil by a factor of 3 to 4 to approximately 40 years which rises doubts rises doubts about the presumed big influence of PyOM as an additional C-sink in soils. On the other hand, although being small the difference in turnover rates is evident and has some major implication with respect to long-term alteration of the chemical composition of OM in fire-affected soils. Based on the obtained results and the analysis of PyOM in other soil systems, a conceptual model is presented which can explain the different behavior of PyOM under different soil conditions.

Experimental warming and antecedent fire alter leaf element composition and increase soil C:N ratio in sub-alpine open heathland.

PubMed

White-Monsant, A C; Clark, G J; Ng Kam Chuen, M A G; Tang, C

2017-10-01

Plant communities in alpine ecosystems worldwide are being altered by climate warming. In the alpine open heathland of the Bogong High Plains, Australia, warming and fire have affected the growth and phenology of plants, and have recently been found to alter soil nutrient availability. We examined the effects of nine years of passive warming by open-top chambers and nine years post-fire on (i) the soluble and extractable nutrients and toxic elements available for plant uptake in the soil and (ii) on the element composition of leaves of seven dominant sub-alpine open heathland plants. Warming increased soil C, soil C:N, and decreased soil δ 13 C, indicating an accumulation of soil organic matter and C sequestration. Warming increased soil δ 15 N, indicating increased N mineralization, which concurred with the increased availability of NH 4 + (measured by ion-exchange membranes). Leaf element composition varied among the plant species in response to changes in soil element availabilities, suggesting the importance of species-specific knowledge. Warming decreased leaf N concentration and increased leaf C:N, generally in the plant community, and specifically in Asterolasia trymalioides, Carex breviculmis, Poa hiemata, and Rytidosperma nudiflorum. Warming increased soil P availability, but did not significantly affect leaf P in any species. Antecedent fire increased soil C:N, and decreased concentrations of Ca and Mg in Celmisia pugioniformis more than in the other species. The results suggest that warming and fire changed the nutrient composition of plants and increased soil C:N, which might lead to progressive N limitation in the alpine ecosystem. Copyright © 2017 Elsevier B.V. All rights reserved.

Landform position and charring conditions control decomposition of soil organic matter and pyrogenic carbon

NASA Astrophysics Data System (ADS)

Abney, R.; Jin, L.; Berhe, A. A.

2017-12-01

Wildfire is a significant global control on both ecosystem properties and biogeochemical cycling, and wildfires are projected to increase in both size and severity with continued climate change. Post-fire, charred biomass, or pyrogenic carbon, is left behind as a significant, relatively slow-cycling component of the soil organic matter pool. Pyrogenic carbon has a turnover time on the centennial scale, and previous research has demonstrated that it is highly susceptible to erosion. However, the interaction of the roles of landform position and combustion temperature remains unexplored. We collected live Pinus jeffreyi bark and charred it under combustion conditions at three temperatures (200°C, 350°C, and 500°C). The charred bark was mixed with soil collected from both eroding and depositional landform positions and incubated for six months. Throughout this incubation, microbial respiration was monitored via collection of CO2, and cumulative respiration was fitted using both single- and multi-pool exponential models. Overall, respiration was highest in soil and char mixtures in the depositional landform positions. Pyrogenic carbon concentrations, as determined by the Kurth Mackenzie Deluca method, declined only slightly in the 200°C char mixed with the depositional soil. Scanning electron microscopy images of the chars before and after incubation illustrate some incorporation of soil organic matter into the structures of the char, and some breakdown of the physical structures of the char. Altogether, the lower temperature chars mixed with the soil from the depositional landform position had the highest decomposition rates, which suggests the role that landform position may play on the stability of pyrogenic carbon at the landscape scale. Furthermore, this implies that the post-fire erosional re-distribution of pyrogenic carbon may act as a significant control of its long-term stabilization in soil and landscape-scale soil carbon stocks.

Ten Years of Post-Fire Vegetation Recovery following the 2007 Zaca Fire using Landsat Satellite Imagery

NASA Astrophysics Data System (ADS)

Hallett, J. K. E.; Miller, D.; Roberts, D. A.

2017-12-01

Forest fires play a key role in shaping eco-systems. The risk to vegetation depends on the fire regime, fuel conditions (age and amount), fire temperature, and physiological characteristics such as bark thickness and stem diameter. The 2007 Zaca Fire (24 kilometers NE of Buellton, Santa Barbara County, California) burned 826.4 km2 over the course of 2 months. In this study, we used a time series of Landsat 5 Thematic Mapper and Landsat 8 Operational Land Imager imagery, to evaluate plant burn severity and post fire recovery as defined into classes of above average recovery, normal recovery, and below average recovery. We spectrally unmixed the images into green vegetation (GV), non-photosynthetic vegetation (NPV), soil surface (SOIL), and ash with a spectral library developed using Constrained Reference Endmember Selection (CRES). We delineated the fire perimeter using the differenced Normalized Burn Ratio (dNBR) and evaluated changes in this index and the Normalized Difference Vegetation Index through time. The results showed an immediate decline in GV and NPV fractions, with a rise in soil and ash fractions directly following the fire, with a slow recovery in GV fraction and a loss of bare soil cover. The was a sharp increase in the ash fraction following the fire and gradual decrease in the year after. Most areas have recovered as of 2017, with prominent recovery in the center of the burn scar and reduced recovery in areas to the south. These results indicate how post-fire vegetation varies based on initial burn severity and pre-fire GV and NPV fractions.

Variation in soil enzyme activity as a function of vegetation amount, type, and spatial structure in fire-prone Mediterranean shrublands.

PubMed

Mayor, Ángeles G; Goirán, Silvana B; Vallejo, V Ramón; Bautista, Susana

2016-12-15

Fire-prone Mediterranean shrublands may be seriously threatened by land degradation due to progressive opening of the vegetation cover driven by increasing drought and fire recurrence. However, information about the consequences of this opening process for critical ecosystem functions is scant. In this work, we studied the influence of vegetation amount, type, and spatial pattern in the variation of extracellular soil enzyme activity (acid phosphatase, β-glucosidase, and urease) in fire-prone shrublands in eastern Spain. Soil was sampled in vegetation-patch and open-interpatch microsites in 15 shrubland sites affected by large wildfires in 1991. On average, the activities of the three enzymes were 1.5 (β-glucosidase and urease) to 1.7 (acid phosphatase) times higher in soils under vegetation patches than in adjacent interpatches. In addition, phosphatase activity for both microsites significantly decreased with the fragmentation of the vegetation. This result was attributed to a lower influence of roots -the main source of acid phosphatase- in the bigger interpatches of the sites with lower patch cover, and to feedbacks between vegetation pattern, redistribution of resources, and soil quality during post-fire vegetation dynamics. Phosphatase activity was also 1.2 times higher in patches of resprouter plants than in patches of non-resprouters, probably due to the faster post-fire recovery and older age of resprouter patches in these fire-prone ecosystems. The influence on the studied enzymes of topographic and climatic factors acting at the landscape scale was insignificant. According to our results, variations in the cover, pattern, and composition of vegetation patches may have profound impacts on soil enzyme activity and associated nutrient cycling processes in fire-prone Mediterranean shrublands, particularly in those related to phosphorus. Copyright © 2016 Elsevier B.V. All rights reserved.

The effects of past climate variability on fire and vegetation in the cerrãdo savanna ecosystem of the Huanchaca Mesetta, Noel Kempff Mercado National Park, NE Bolivia

NASA Astrophysics Data System (ADS)

Maezumi, S. Y.; Power, M. J.; Mayle, F. E.; McLauchlan, K.; Iriarte, J.

2015-01-01

Cerrãdo savannas have the greatest fire activity of all major global land-cover types and play a significant role in the global carbon cycle. During the 21st century, temperatures are predicted to increase by ~ 3 °C coupled with a precipitation decrease of ~ 20%. Although these conditions could potentially intensify drought stress, it is unknown how that might alter vegetation composition and fire regimes. To assess how Neotropical savannas responded to past climate changes, a 14 500 year, high-resolution, sedimentary record from Huanchaca Mesetta, a palm swamp located in the cerrãdo savanna in northeastern Bolivia, was analyzed for phytoliths, stable isotopes and charcoal. A non-analogue, cold-adapted vegetation community dominated the Late Glacial-Early Holocene period (14 500-9000 ka), that included trees and C3 Pooideae and C4 Panicoideae grasses. The Late Glacial vegetation was fire sensitive and fire activity during this period was low, likely responding to fuel availability and limitation. Although similar vegetation characterized the Early Holocene, the warming conditions associated with the onset of the Holocene led to an initial increase in fire activity. Huanchaca Mesetta became increasingly fire-dependent during the Middle Holocene with the expansion of C4 fire adapted grasses. However, as warm, dry conditions, characterized by increased length and severity of the dry season, continued, fuel availability decreased. The establishment of the modern palm swamp vegetation occurred at 5000 cal yr BP. Edaphic factors are the first order control on vegetation on the rocky quartzite mesetta. Where soils are sufficiently thick, climate is the second order control of vegetation on the mesetta. The presence of the modern palm swamp is attributed to two factors: (1) increased precipitation that increased water table levels, and (2) decreased frequency and duration of surazos leading to increased temperature minima. Natural (soil, climate, fire) drivers rather than anthropogenic drivers control the vegetation and fire activity at Huanchaca Mesetta. Thus the cerrãdo savanna ecosystem of the Huanchaca Plateau has exhibited ecosystem resilience to major climatic changes in both temperature and precipitation since the Late Glacial period.

The impact of traditional fire management on soil carbon and nitrogen pools in a montane forest, southern Ethiopia

Treesearch

Dong-Gill Kim; Habitamu Taddese; Abrham Belay; Randy Kolka

2016-01-01

We conducted studies to assess the impact of traditional fire management on soil organic carbon and total nitrogen pools. We compared organic carbon and total nitrogen pools in forest floor and mineral soil (0–100-cm depth) in three areas burned by local communities (B) with adjacent unburned areas (UB) (three paired sites; 1, 5 and 9 years since fire; hereafter B1-UB...

Resource homogenization in degraded arid landscapes induced by fire - erosion interactions

NASA Astrophysics Data System (ADS)

Ravi, S.; D'Odorico, P.; Wang, L.; Collins, S. L.; White, C. S.; Okin, G. S.

2007-12-01

Hydrological and aeolian processes are major drivers in the dynamics of arid landscapes in that they redistribute soil resources with important implications on the composition and spatial patterns of dryland vegetation. These processes are thought to play a major role in the conversion of disturbed desert grasslands into shrublands, with possible impacts on regional climate and desertification. At its early stages the grassland-to-shrubland transition can be still reversible and fires have been shown to contribute to the reversibility of the system. Even though fires are know to interact both with wind and water erosion, an understanding of these interactions and of their effect on aridland degradation is still missing. Here we use field manipulation experiments in a grass-shrub transition zone in the Chihuahuan desert to show how the interaction of fires with erosion processes may affect the distribution of soil resources with consequent effects on the pace of land degradation processes. Using microtopography measurements and isotopic analyses, we provide experimental evidence for the occurrence of post-fire enhancement of soil erosion, and relate this effect to the weakening of interparticle bonding forces associated with the emergence of fire-induced soil hydrophobicity. We also show how this effect favors the reversibility of the early stages of shrub-to-grass transition through the redistribution of soil resources from the fertile shrub-dominated areas (or "fertility islands") to the bare soil interspaces.

Four millennia of woodland structure and dynamics at the Arctic treeline of eastern Canada.

PubMed

Auger, Sarah; Payette, Serge

2010-05-01

Paleoecological analysis using complementary indicators of vegetation and soil can provide spatially explicit information on ecological processes influencing trajectories of long-term ecosystem change. Here we document the structure and dynamics of an old-growth woodland before and after its inception 1000 years ago. We infer vegetation and soil characteristics from size and age distributions of black spruce (Picea mariana (Mill.) B.S.P.), soil properties, plant fossils, and paleosols. Radiocarbon ages of charcoal on the ground and in the soil indicate that the fire return interval was approximately 300 years between 2750 and 1000 cal. yr BP. No fire evidence was found before and after this period despite the presence of spruce since 4200 cal. yr BP. The size structures of living and dead spruce suggest that the woodland is in equilibrium with present climate in absence of fire. Tree establishment and mortality occurred regularly since the last fire event around 950 cal. yr BP. Both layering and occasional seeding have contributed to stabilize the spatial distribution of spruce over the past 1000 years. Since initial afforestation, soil development has been homogenized by the changing spatial distribution of spruce following each fire. We conclude that the history of the woodland is characterized by vegetation shifts associated with fire and soil disturbances and by millennial-scale maintenance of the woodland's structure despite changing climatic conditions.

Nitrogen balance along a northern boreal forest fire chronosequence.

PubMed

Palviainen, Marjo; Pumpanen, Jukka; Berninger, Frank; Ritala, Kaisa; Duan, Baoli; Heinonsalo, Jussi; Sun, Hui; Köster, Egle; Köster, Kajar

2017-01-01

Fire is a major natural disturbance factor in boreal forests, and the frequency of forest fires is predicted to increase due to climate change. Nitrogen (N) is a key determinant of carbon sequestration in boreal forests because the shortage of N limits tree growth. We studied changes in N pools and fluxes, and the overall N balance across a 155-year non stand-replacing fire chronosequence in sub-arctic Pinus sylvestris forests in Finland. Two years after the fire, total ecosystem N pool was 622 kg ha-1 of which 16% was in the vegetation, 8% in the dead biomass and 76% in the soil. 155 years after the fire, total N pool was 960 kg ha-1, with 27% in the vegetation, 3% in the dead biomass and 69% in the soil. This implies an annual accumulation rate of 2.28 kg ha-1 which was distributed equally between soil and biomass. The observed changes in N pools were consistent with the computed N balance +2.11 kg ha-1 yr-1 over the 155-year post-fire period. Nitrogen deposition was an important component of the N balance. The biological N fixation increased with succession and constituted 9% of the total N input during the 155 post-fire years. N2O fluxes were negligible (≤ 0.01 kg ha-1 yr-1) and did not differ among post-fire age classes. The number and intensity of microbial genes involved in N cycling were lower at the site 60 years after fire compared to the youngest and the oldest sites indicating potential differences in soil N cycling processes. The results suggest that in sub-arctic pine forests, the non-stand-replacing, intermediate-severity fires decrease considerably N pools in biomass but changes in soil and total ecosystem N pools are slight. Current fire-return interval does not seem to pose a great threat to ecosystem productivity and N status in these sub-arctic forests.

Nitrogen balance along a northern boreal forest fire chronosequence

PubMed Central

Pumpanen, Jukka; Berninger, Frank; Ritala, Kaisa; Duan, Baoli; Heinonsalo, Jussi; Sun, Hui; Köster, Egle; Köster, Kajar

2017-01-01

Fire is a major natural disturbance factor in boreal forests, and the frequency of forest fires is predicted to increase due to climate change. Nitrogen (N) is a key determinant of carbon sequestration in boreal forests because the shortage of N limits tree growth. We studied changes in N pools and fluxes, and the overall N balance across a 155-year non stand-replacing fire chronosequence in sub-arctic Pinus sylvestris forests in Finland. Two years after the fire, total ecosystem N pool was 622 kg ha-1 of which 16% was in the vegetation, 8% in the dead biomass and 76% in the soil. 155 years after the fire, total N pool was 960 kg ha-1, with 27% in the vegetation, 3% in the dead biomass and 69% in the soil. This implies an annual accumulation rate of 2.28 kg ha-1 which was distributed equally between soil and biomass. The observed changes in N pools were consistent with the computed N balance +2.11 kg ha-1 yr-1 over the 155-year post-fire period. Nitrogen deposition was an important component of the N balance. The biological N fixation increased with succession and constituted 9% of the total N input during the 155 post-fire years. N2O fluxes were negligible (≤ 0.01 kg ha-1 yr-1) and did not differ among post-fire age classes. The number and intensity of microbial genes involved in N cycling were lower at the site 60 years after fire compared to the youngest and the oldest sites indicating potential differences in soil N cycling processes. The results suggest that in sub-arctic pine forests, the non-stand-replacing, intermediate-severity fires decrease considerably N pools in biomass but changes in soil and total ecosystem N pools are slight. Current fire-return interval does not seem to pose a great threat to ecosystem productivity and N status in these sub-arctic forests. PMID:28358884

Surface soil root distribution and possible interaction with site factors in a young longleaf pine stand

Treesearch

Mary Anne Sword Sayer

2013-01-01

Interaction between soil bulk density and low soil water content may create root growth-limiting soil strengths. In a Louisiana longleaf pine (Pinus palustris Mill.) stand, soil strength at the zero- to 20.0-cm depth was assessed in response to no fire or biennial fires in May. At the 5.0- to 20.0-cm depth, one-half of the measurements were...

Stabilization of Pb²⁺ and Cu²⁺ contaminated firing range soil using calcined oyster shells and waste cow bones.

PubMed

Moon, Deok Hyun; Cheong, Kyung Hoon; Khim, Jeehyeong; Wazne, Mahmoud; Hyun, Seunghun; Park, Jeong-Hun; Chang, Yoon-Young; Ok, Yong Sik

2013-05-01

Pb(2+) and Cu(2+) contamination at army firing ranges poses serious environmental and health risks to nearby communities necessitating an immediate and prompt remedial action. In this study, a novel mixture of calcined oyster shells (COSs) and waste cow bones (WCBs) was utilized to immobilize Pb(2+) and Cu(2+) in army firing range soils. The effectiveness of the treatment was evaluated based on the Korean Standard leaching test. The treatment results showed that Pb(2+) and Cu(2+) immobilization in the army firing range soil was effective in significantly reducing Pb(2+) and Cu(2+) leachability upon the combined treatment with COS and WCB. A drastic reduction in Pb(2+) (99%) and Cu(2+) leachability (95%) was obtained as compared to the control sample, upon treatment with 5 wt.% COS and 5 wt.% WCB. The combination treatment of COS and WCB was more effective for Pb immobilization, than the treatment with COS or WCB alone. The 5 wt.% COS alone treatment resulted in 95% reduction in Cu(2+) leachability. The SEM-EDX results suggested that Pb(2+) and Cu(2+) immobilization was most probably associated with the formation of ettringite, pozzolanic reaction products and pyromorphite-like phases at the same time. Copyright © 2013 Elsevier Ltd. All rights reserved.

Soil fungal communities respond compositionally to recurring frequent prescribed burning in a managed southeastern US forest ecosystem

Treesearch

Alena K. Oliver; Mac A. Callaham; Ari Jumpponen

2015-01-01

Prescribed fire is an important management tool to reduce fuel loads, to remove non-fire adapted species and to sustain fire-adapted taxa in many forested ecosystems of the southeastern USA. Yet, the long-term effects of recurring prescribed fires on soil fungi and their communities in these ecosystems remain unclear. We Illumina MiSeq sequenced and analyzed fungal...

Fungal Community Shifts in Structure and Function across a Boreal Forest Fire Chronosequence

PubMed Central

Santalahti, Minna; Pumpanen, Jukka; Köster, Kajar; Berninger, Frank; Raffaello, Tommaso; Jumpponen, Ari; Asiegbu, Fred O.; Heinonsalo, Jussi

2015-01-01

Forest fires are a common natural disturbance in forested ecosystems and have a large impact on the microbial communities in forest soils. The response of soil fungal communities to forest fire is poorly documented. Here, we investigated fungal community structure and function across a 152-year boreal forest fire chronosequence using high-throughput sequencing of the internal transcribed spacer 2 (ITS2) region and a functional gene array (GeoChip). Our results demonstrate that the boreal forest soil fungal community was most diverse soon after a fire disturbance and declined over time. The differences in the fungal communities were explained by changes in the abundance of basidiomycetes and ascomycetes. Ectomycorrhizal (ECM) fungi contributed to the increase in basidiomycete abundance over time, with the operational taxonomic units (OTUs) representing the genera Cortinarius and Piloderma dominating in abundance. Hierarchical cluster analysis by using gene signal intensity revealed that the sites with different fire histories formed separate clusters, suggesting differences in the potential to maintain essential biogeochemical soil processes. The site with the greatest biological diversity had also the most diverse genes. The genes involved in organic matter degradation in the mature forest, in which ECM fungi were the most abundant, were as common in the youngest site, in which saprotrophic fungi had a relatively higher abundance. This study provides insight into the impact of fire disturbance on soil fungal community dynamics. PMID:26341215

Use of urban composts for the regeneration of a burnt Mediterranean soil: a laboratory approach.

PubMed

Cellier, Antoine; Francou, Cédric; Houot, Sabine; Ballini, Christine; Gauquelin, Thierry; Baldy, Virginie

2012-03-01

In Mediterranean region, forest fires are a major problem leading to the desertification of the environment. Use of composts is considered as a solution for soil and vegetation rehabilitation. In this study, we determined under laboratory conditions the effects of three urban composts and their mode of application (laid on the soil surface or mixed into the soil) on soil restoration after fire: a municipal waste compost (MWC), a compost of sewage sludge mixed with green waste (SSC) and a green waste compost (GWC). Carbon (C) and nitrogen (N) mineralisation, total microbial biomass, fungal biomass and soil characteristics were measured during 77-day incubations in microcosms. The impact of composts input on hydrological behaviour related to erodibility was estimated by measuring runoff, retention and percolation (i.e. infiltration) of water using a rainfall simulator under laboratory conditions. Input of composts increased organic matter and soil nutrient content, and enhanced C and N mineralisation and total microbial biomass throughout the incubations, whereas it increased sporadically fungal biomass. For all these parameters, the MWC induced the highest improvement while GWC input had no significant effect compared to the control. Composts mixed with soil weakly limited runoff and infiltration whereas composts laid at the soil surface significantly reduced runoff and increased percolation and retention, particularly with the MWC. Copyright © 2010 Elsevier Ltd. All rights reserved.

Vertical Distribution of Soil Denitrifying Communities in a Wet Sclerophyll Forest under Long-Term Repeated Burning.

PubMed

Liu, Xian; Chen, Chengrong; Wang, Weijin; Hughes, Jane M; Lewis, Tom; Hou, Enqing; Shen, Jupei

2015-11-01

Soil biogeochemical cycles are largely mediated by microorganisms, while fire significantly modifies biogeochemical cycles mainly via altering microbial community and substrate availability. Majority of studies on fire effects have focused on the surface soil; therefore, our understanding of the vertical distribution of microbial communities and the impacts of fire on nitrogen (N) dynamics in the soil profile is limited. Here, we examined the changes of soil denitrification capacity (DNC) and denitrifying communities with depth under different burning regimes, and their interaction with environmental gradients along the soil profile. Results showed that soil depth had a more pronounced impact than the burning treatment on the bacterial community size. The abundance of 16S rRNA and denitrification genes (narG, nirK, and nirS) declined exponentially with soil depth. Surprisingly, the nosZ-harboring denitrifiers were enriched in the deeper soil layers, which was likely to indicate that the nosZ-harboring denitrifiers could better adapt to the stress conditions (i.e., oxygen deficiency, nutrient limitation, etc.) than other denitrifiers. Soil nutrients, including dissolved organic carbon (DOC), total soluble N (TSN), ammonium (NH(4)(+)), and nitrate (NO(3)(-)), declined significantly with soil depth, which probably contributed to the vertical distribution of denitrifying communities. Soil DNC decreased significantly with soil depth, which was negligible in the depths below 20 cm. These findings have provided new insights into niche separation of the N-cycling functional guilds along the soil profile, under a varied fire disturbance regime.

The role of spatial heterogeneity of the environment in soil fauna recovery after fires

NASA Astrophysics Data System (ADS)

Gongalsky, K. B.; Zaitsev, A. S.

2016-12-01

Forest fires are almost always heterogeneous, leaving less-disturbed sites that are potentially suitable as habitats for soil-dwelling creatures. The recovery of large soil animal communities after fires is therefore dependent on the spatial structure of the burned habitats. The role of locally less disturbed sites in the survival of soil macrofauna communities along with traditionally considered immigration from the surrounding undisturbed habitats is shown by the example of burnt areas located in three geographically distant regions of European Russia. Such unburned soil cover sites (perfugia) occupy 5-10% of the total burned habitats. Initially, perfugia are characterized by much higher (200-300% of the average across a burned area) diversity and abundance of soil fauna. A geostatistical method made it possible to estimate the perfugia size for soil macrofauna at 3-8 m.

Soil resources influence vegetation and response to fire and fire-surrogate treatments in sagebrush-steppe ecosystems

USGS Publications Warehouse

Rau, Benjamin M.; Chambers, Jeanne C.; Pyke, David A.; Roundy, Bruce A.; Schupp, Eugene W.; Doescher, Paul; Caldwell, Todd G.

2014-01-01

Current paradigm suggests that spatial and temporal competition for resources limit an exotic invader, cheatgrass (Bromus tectorum L.), which once established, alters fire regimes and can result in annual grass dominance in sagebrush steppe. Prescribed fire and fire surrogate treatments (mowing, tebuthiuron, and imazapic) are used to reduce woody fuels and increase resistance to exotic annuals, but may alter resource availability and inadvertently favor invasive species. We used four study sites within the Sagebrush Steppe Treatment Evaluation Project (SageSTEP) to evaluate 1) how vegetation and soil resources were affected by treatment, and 2) how soil resources influenced native herbaceous perennial and exotic annual grass cover before and following treatment. Treatments increased resin exchangeable NH4+, NO3−, H2PO4−, and K+, with the largest increases caused by prescribed fire and prolonged by application of imazapic. Burning with imazapic application also increased the number of wet growing degree days. Tebuthiuron and imazapic reduced exotic annual grass cover, but imazapic also reduced herbaceous perennial cover when used with prescribed fire. Native perennial herbaceous species cover was higher where mean annual precipitation and soil water resources were relatively high. Exotic annual grass cover was higher where resin exchangeable H2PO4− was high and gaps between perennial plants were large. Prescribed fire, mowing, and tebuthiuron were successful at increasing perennial herbaceous cover, but the results were often ephemeral and inconsistent among sites. Locations with sandy soil, low mean annual precipitation, or low soil water holding capacity were more likely to experience increased exotic annual grass cover after treatment, and treatments that result in slow release of resources are needed on these sites. This is one of few studies that correlate abiotic variables to native and exotic species cover across a broad geographic setting, and that demonstrates how soil resources potentially influence the outcome of management treatments.

Recovery of microbial community structure and functioning after wildfire in semi-arid environments: optimising methods for monitoring and assessment

NASA Astrophysics Data System (ADS)

Muñoz-Rojas, Miriam; Martini, Dylan; Erickson, Todd; Merritt, David; Dixon, Kingsley

2015-04-01

Introduction In semi-arid areas such as northern Western Australia, wildfires are a natural part of the environment and many ecosystems in these landscapes have evolved and developed a strong relationship with fire. Soil microbial communities play a crucial role in ecosystem processes by regulating the cycling of nutrients via decomposition, mineralization, and immobilization processes. Thus, the structure (e.g. soil microbial biomass) and functioning (e.g. soil microbial activity) of microbial communities, as well as their changes after ecosystem disturbance, can be useful indicators of soil quality and health recovery. In this research, we assess the impacts of fire on soil microbial communities and their recovery in a biodiverse semi-arid environment of Western Australia (Pilbara region). New methods for determining soil microbial respiration as an indicator of microbial activity and soil health are also tested. Methodology Soil samples were collected from 10 similar ecosystems in the Pilbara with analogous native vegetation, but differing levels of post-fire disturbance (i.e. 3 months, 1 year, 5, 7 and 14 years after wildfire). Soil microbial activity was measured with the Solvita test which determines soil microbial respiration rate based on the measurement of the CO2 burst of a dry soil after it is moistened. Soils were dried and re-wetted and a CO2 probe was inserted before incubation at constant conditions of 25°C during 24 h. Measurements were taken with a digital mini spectrometer. Microbial (bacteria and fungi) biomass and community composition were measured by phospholipid fatty acid analysis (PLFA). Results Immediately after the fire (i.e. 3 months), soil microbial activity and microbial biomass are similar to 14 years 'undisturbed' levels (53.18±3.68 ppm CO2-CO and 14.07±0.65 mg kg-1, respectively). However, after the first year post-fire, with larger plant productivity, microbial biomass and microbial activity increase rapidly, peaking after 5-7 years post fire (70.70±8.94 ppm CO2-CO and 21.67±2.62 mg kg-1, respectively). Microbial activity measured with the Solvita test was significantly correlated (R Pearson > 0.7; P < 0.001) with microbial parameters analysed with PLFA such as microbial biomass, bacteria biomass or mycorrhizhal fungi. This method has proven to be reliable, fast and easy to interpret for assessment of soil microbial activity in the recovery of soil quality during the recovery after fire. Keywords Pilbara region, biodiverse ecosystems, microbial biomass, microbial respiration, Solvita test, CO2 burst.

Effect of Experimentally Manipulated Fire Regimes on the Response of Forests to Drought

NASA Astrophysics Data System (ADS)

Refsland, T. K.; Knapp, B.; Fraterrigo, J.

2017-12-01

Climate change is expected to increase drought stress in many forests and alter fire regimes. Fire can reduce tree density and thus competition for limited water, but the effects of changing fire regimes on forest productivity during drought remain poorly understood. We measured the annual ring-widths of adult oak (Quercus spp.) trees in Mark Twain National Forest, Missouri USA that experienced unburned, annual or periodic (every 4 years) surface fire treatments from 1951 - 2015. Severe drought events were identified using the BILJOU water balance model. We determined the effect of fire treatment on stand-level annual growth rates as well as stand-level resistance and resilience to drought, defined as the drought-induced reduction in growth and post-drought recovery in growth, respectively. During favorable wet years, annual and periodic fire treatments reduced annual growth rates by approximately 10-15% relative to unburned controls (P < 0.001). Stand-level growth rates declined 22-40% during drought events (P < 0.001), but fire-driven changes to stand basal area had no effect on the resistance or resilience of trees to drought. The decline in annual growth rates of burned stands during favorable wet years was likely caused by increased nitrogen (N) limitation in burned plots. After 60 years of treatment, burned plots experienced 30% declines in total soil N relative to unburned plots. Our finding that drought resistance and resilience were similar across all treatments suggest that fire-driven reductions in stand density may have negligible effects on soil moisture availability during drought. Our results highlight that climate-fire interactions can have important long-term effects on forest productivity.

Effects of fire and three fire-fighting chemicals on main soil properties, plant nutrient content and vegetation growth and cover after 10 years.

PubMed

Fernández-Fernández, M; Gómez-Rey, M X; González-Prieto, S J

2015-05-15

The study addresses a knowledge-gap in the long-term ecological consequences of fire and fire-fighting chemicals. Ten years after a prescribed fire and the application of three fire-fighting chemicals, their effects on the soil-plant system were evaluated. Five treatments were established: unburnt soils (US) and burnt soils treated with water alone (BS), foaming agent (BS+Fo), Firesorb (BS+Fi) and ammonium polyphosphate (BS+Ap). Soils (0-2 cm depth) and foliar material of shrubs (Erica umbellata, Pterospartum tridentatum and Ulex micranthus) and trees (Pinus pinaster) were analysed for total N, δ(15)N, and soil-available and plant total macronutrients and trace elements. Soil pH, NH₄(+)-N and NO₃(-)-N; pine basal diameter and height; and shrub cover and height were also measured. Compared with US plots, burnt soils had less nitrates and more Mo. Although differences were not always significant, BS+Ap had the highest levels of soil available P, Na and Al. Plants from BS+Ap plots had higher values of δ(15)N (P. pinaster and E. umbellata), P (all species), Na (P. tridentatum and U. micranthus) and Mg (E. umbellata and P. tridentatum) than other treatments; while K in plants from BS+Ap plots was the highest among treatments for P. pinaster and the lowest for the shrubs. Pines in US plots were higher and wider than in burnt treatments, except for BS+Ap, where the tallest and widest trees were found, although half of them were either dead (the second highest mortality after BS+Fi) or had a distorted trunk. BS+Ap was the treatment with strongest effects on plants, showing E. umbellata the lowest coverage and height, P. tridentatum the highest coverage, U. micranthus one of the lowest coverages and being the only treatment where Genista triacanthos was absent. Consequently, it is concluded that both fire and ammonium polyphosphate application had significant effects on the soil-plant system after 10 years. Copyright © 2015 Elsevier B.V. All rights reserved.

Predicting Fire Severity and Hydrogeomorphic Effects for Wildland Fire Decision Support

NASA Astrophysics Data System (ADS)

Hyde, K.; Woods, S. W.; Calkin, D.; Ryan, K.; Keane, R.

2007-12-01

The Wildland Fire Decision Support System (WFDSS) uses the Fire Spread Probability (FSPro) model to predict the spatial extent of fire, and to assess values-at-risk within probable spread zones. This information is used to support Appropriate Management Response (AMR), which involves decision making regarding fire-fighter deployment, fire suppression requirements, and identification of areas where fire may be safely permitted to take its course. Current WFDSS assessments are generally limited to a binary prediction of whether or not a fire will reach a given location and an assessment of the infrastructure which may be damaged or destroyed by fire. However, an emerging challenge is to expand the capabilities of WFDSS so that it also estimates the probable fire severity, and hence the effect on soil, vegetation and on hydrologic and geomorphic processes such as runoff and soil erosion. We present a conceptual framework within which derivatives of predictive fire modelling are used to predict impacts upon vegetation and soil, from which fire severity and probable post-fire watershed response can be inferred, before a fire actually occurs. Fire severity predictions are validated using Burned Area Reflectance Classification imagery. Recent tests indicate that satellite derived BARC images are a simple and effective means to predict post-fire erosion response based on relative vegetation disturbance. A fire severity prediction which reasonably approximates a BARC image may therefore be used to assess post-fire erosion and flood potential before fire reaches an area. This information may provide a new avenue of reliable support for fire management decisions.

Frequent fire alters nitrogen transformations in ponderosa pine stands of the inland northwest.

PubMed

DeLuca, Thomas H; Sala, Anna

2006-10-01

Recurrent, low-severity fire in ponderosa pine (Pinus ponderosa)/interior Douglas-fir (Pseudotsuga menziesii var. glauca) forests is thought to have directly influenced nitrogen (N) cycling and availability. However, no studies to date have investigated the influence of natural fire intervals on soil processes in undisturbed forests, thereby limiting our ability to understand ecological processes and successional dynamics in this important ecosystem of the Rocky Mountain West. Here, we tested the standing hypothesis that recurrent fire in ponderosa pine/Douglas-fir forests of the Inland Northwest decreases total soil N, but increases N turnover and nutrient availability. We compared soils in stands unburned over the past 69-130 years vs. stands exposed to two or more fires over the last 130 years at seven distinct locations in two wilderness areas. Mineral soil samples were collected from each of the seven sites in June and July of 2003 and analyzed for pH, total C and N, potentially mineralizable N (PMN), and extractable NH4+, NO3-, PO4(-3), Ca+2, Mg+2, and K+. Nitrogen transformations were assessed at five sites by installing ionic resin capsules in the mineral soil in August of 2003 and by conducting laboratory assays of nitrification potential and net nitrification in aerobic incubations. Total N and PMN decreased in stands subjected to multiple fires. This loss of total N and labile N was not reflected in concentrations of extractable NH4+ and NO3-. Rather, multiple fires caused an increase in NO3 sorbed on ionic resins, nitrification potential, and net nitrification in spite of the burned stands not having been exposed to fire for at least 12-17 years. Charcoal collected from a recent fire site and added to unburned soils increased nitrification potential, suggesting that the decrease of charcoal in the absence of fire may play an important role in N transformations in fire-dependent ecosystems in the long term. Interestingly, we found no consistent effect of fire frequency on extractable P or alkaline metal concentrations. Our results corroborate the largely untested hypothesis that frequent fire in ponderosa pine forests increases inorganic N availability in the long term and emphasize the need to study natural, unmanaged sites in far greater detail.

Prescribed fire and timber harvesting effects on soil carbon and nitrogen in a pine forest

USDA-ARS?s Scientific Manuscript database

Thinning and prescribed fire are common management tools used to eliminate thick fuel loads that could otherwise facilitate and encourage a more severe catastrophic wildfire. The objective of this study was to quantify the lasting effects of prescribed fire on forest floor and soil nutrients approxi...

Fire, climate change, and forest resilience in interior Alaska

Treesearch

Jill F. Johnstone; F. Stuart Chapin; Teresa N. Hollingsworth; Michelle C. Mack; Vladimir Romanovsky; Merritt Turetsky

2010-01-01

In the boreal forests of interior Alaska, feedbacks that link forest soils, fire characteristics, and plant traits have supported stable cycles of forest succession for the past 6000 years. This high resilience of forest stands to fire disturbance is supported by two interrelated feedback cycles: (i) interactions among disturbance regime and plant-soil-microbial...

Fire-severity effects on plant-fungal interactions after a novel tundra wildfire disturbance: implications for arctic shrub and tree migration

Treesearch

Rebecca E. Hewitt; Teresa N. Hollingsworth; F. Stuart Chapin III; D. Lee Taylor

2016-01-01

Background: Vegetation change in high latitude tundra ecosystems is expected to accelerate due to increased wildfire activity. High-severity fires increase the availability of mineral soil seedbeds, which facilitates recruitment, yet fire also alters soil microbial composition, which could significantly impact seedling establishment.

Effects of post-fire wood management strategies on vegetation recovery and land surface temperature (LST) estimated from Landsat images

NASA Astrophysics Data System (ADS)

Vlassova, Lidia; Pérez-Cabello, Fernando

2016-02-01

The study contributes remote sensing data to the discussion about effects of post-fire wood management strategies on forest regeneration. Land surface temperature (LST) and Normalized Differenced Vegetation Index (NDVI), estimated from Landsat-8 images are used as indicators of Pinus halepensis ecosystem recovery after 2008 fire in areas of three post-fire treatments: (1) salvage logging with wood extraction from the site on skidders in suspended position (SL); (2) snag shredding in situ leaving wood debris in place (SS) performed two years after the event; and (3) non-intervention control areas (CL) where all snags were left standing. Six years after the fire NDVI values ∼0.5 estimated from satellite images and field radiometry indicate considerable vegetation recovery due to efficient regeneration traits developed by the dominant plant species. However, two years after management activities in part of the burnt area, the effect of SL and SS on ecosystem recovery is observed in terms of both LST and NDVI. Statistically significant differences are detected between the intervened areas (SL and SS) and control areas of non-intervention (CL); no difference is registered between zones of different intervention types (SL and SS). CL areas are on average 1 °C cooler and 10% greener than those corresponding to either SL or SS, because of the beneficial effects of burnt wood residuals, which favor forest recovery through (i) enhanced nutrient cycling in soils, (ii) avoidance of soil surface disturbance and mechanical damage of seedlings typical to the managed areas, and (iii) ameliorated microclimate. The results of the study show that in fire-resilient ecosystems, such as P. halepensis forests, NDVI is higher and LST is lower in areas with no management intervention, being an indication of more favorable conditions for vegetation regeneration.

Homogenization of the soil surface following fire in semiarid grasslands

Treesearch

Carleton S. White

2011-01-01

Semiarid grasslands accumulate soil beneath plant "islands" that are raised above bare interspaces. This fine-scale variation in microtopographic relief is plant-induced and is increased with shrub establishment. Research found that fire-induced water repellency enhanced local-scale soil erosion that reduced variation in microtopographic relief, suggesting...

Improving rangeland seeding success in post-fire water repellent soil using surfactant seed coating technology

USDA-ARS?s Scientific Manuscript database

Severe disturbance from catastrophic wildfires often requires that native plant materials be reintroduced through reseeding, but the success rate of these restoration efforts in arid environments is notoriously low. Post-fire soil water repellency can limit reseeding success by decreasing soil moist...

Chapter 3: Soil Chemistry

Treesearch

Jennifer D. Knoepp; Leonard F. DeBano; Daniel G. Neary

2005-01-01

The chemical properties of the soil that are affected by fire include individual chemical characteristics, chemical reactions, and chemical processes (DeBano and others 1998). The soil chemical characteristics most commonly affected by fire are organic matter, carbon (C), nitrogen (N), phosphorus (P), sulfur (S), cations, cation exchange capacity, pH, and buffer power...

Post-fire changes in sediment transport connectivity from pedon to watershed scale. The Navalón wildfire in Eastern Spain

NASA Astrophysics Data System (ADS)

Cerdà, Artemi; Bodí, Merche B.; González, Óscar; Mataix Solera, Jorge; Doerr, Stefan Helmut

2015-04-01

Wildfire are present in the Earth System since vegetation was present in the continents (Doerr and Cerdà, 2005; Kaiho et al., 2013). Forest fire cause damage in the soil and the vegetation cover (Guénon et al., 2013). The years after a forest fire there is a sudden increase in the soil erosion rates that contribute to connect the pedon, slope tram, tram and watershed with surface flows that results in high erosion rates (Cerdà and Lasanta, 2005; Lasanta and Cerdà, 2005; Cawson et al., 2012; Pérez Cabello et al., 2012; Prats et al., 2015). Although the research on soil erosion after forest fire was carried out at different scales by different authors, there is not information about soil erosion at different scales at the same research site and during the post fire period. After the forest fire of April 2008 in Navalón, Eastern Spain, the Soil Erosion and Degradation Research Group from the University of Valencia initiated the measurement of the soil losses at pedon scale (microplots of 0.30 m2), at slope tram (silt fences of 1.8 m width), at slope scale (abandoned terraces) and at watershed scale, at the bottom of the valley (abandoned terraces). The results show that there is a reduction in the sediment yield from pedon to watershed scale and that the soil erosion took place in the first year after the fire. Acknowledgements To the "Ministerio de Economía and Competitividad" of Spanish Government for finance the POSTFIRE project (CGL2013- 47862-C2-1-R). The research projects GL2008-02879/BTE, LEDDRA 243857 and PREVENTING AND REMEDIATING DEGRADATION OF SOILS IN EUROPE THROUGH LAND CARE (RECARE)FP7-ENV-2013- supported this research. References Carreiras, M., Ferreira, A.J.D., Valente, S., Fleskens, L., Gonzales-Pelayo, Ó., Rubio, J.L., Stoof, C.R., Coelho, C.O.A., Ferreira, C.S.S., Ritsema, C.J. 2014. Comparative analysis of policies to deal with the wildfire risk. Land Degradation & Development, 25, 92-103. http://dx.doi.org/10.1002/ldr.2274 Cawson, J. G., Sheridan, G. J., Smith, H. G., Lane, P. N. J. (2012). Surface runoff and erosion after prescribed burning and the effect of different fire regimes in forests and shrublands: a review. International Journal of Wildland Fire, 21(7), 857-872. Cerdà, A., Lasanta, A. 2005. Long-term erosional responses after fire in the Central Spanish Pyrenees: 1. Water and sediment yield. Catena, 60, 59-80. Doerr, S., Cerdà, A. 2005. Fire effects on soil system functioning: new insights and future challenges International Journal of Wildland Fire Preface. International Journal of Wildland Fire 14(4) 339-342 Guénon, R., Vennetier, M., Dupuy, N., Roussos, S., Pailler, A., Gros, R. 2013. Trends in recovery of Mediterranean soil chemical properties and microbial activities after infrequent and frequent wildfires. Land Degradation & Development, 24: 115- 128. DOI 10.1002/ldr.1109 Kaiho, K., Yatsu, S., Oba, M., Gorjan, P., Casier, J. G., Ikeda, M. (2013). A forest fire and soil erosion event during the Late Devonian mass extinction. Palaeogeography, Palaeoclimatology, Palaeoecology, 392, 272-280. Lasanta, A., Cerdà, A. 2005. Long-term erosional responses after fire in the Central Spanish Pyrenees: 2. Solute release. Catena, 60, 80-101. Pérez-Cabello, F., Cerdà, A., de la Riva, J., Echeverría, M.T., García-Martín, A., Ibarra, P., Lasanta, T., Montorio, R., Palacios, V. 2012. Micro-scale post-fire surface cover changes monitored using high spatial resolution photography in a semiarid environment: A useful tool in the study of post-fire soil erosion processes, Journal of Arid Environments, 76: 88-96. 10.1016/j.jaridenv.2011.08.007 Prats, S.A., Malvar, M.C., Simões-Vieira, D.C., MacDonald, L., Keizer, J.J. 2015. Effectiveness of hydro- mulching to reduce runoff and erosion in a recently burnt pine plantation in central Portugal. Land Degradation & Development, DOI: 10.1002/ldr.2236.

Long-term frequent prescribed fire decreases surface soil carbon and nitrogen pools in a wet sclerophyll forest of Southeast Queensland, Australia.

PubMed

Muqaddas, Bushra; Zhou, Xiaoqi; Lewis, Tom; Wild, Clyde; Chen, Chengrong

2015-12-01

Prescribed fire is one of the most widely-used management tools for reducing fuel loads in managed forests. However the long-term effects of repeated prescribed fires on soil carbon (C) and nitrogen (N) pools are poorly understood. This study aimed to investigate how different fire frequency regimes influence C and N pools in the surface soils (0-10 cm). A prescribed fire field experiment in a wet sclerophyll forest established in 1972 in southeast Queensland was used in this study. The fire frequency regimes included long unburnt (NB), burnt every 2 years (2yrB) and burnt every 4 years (4yrB), with four replications. Compared with the NB treatment, the 2yrB treatment lowered soil total C by 44%, total N by 54%, HCl hydrolysable C and N by 48% and 59%, KMnO4 oxidizable C by 81%, microbial biomass C and N by 42% and 33%, cumulative CO2-C by 28%, NaOCl-non-oxidizable C and N by 41% and 51%, and charcoal-C by 17%, respectively. The 4yrB and NB treatments showed no significant differences for these soil C and N pools. All soil labile, biologically active and recalcitrant and total C and N pools were correlated positively with each other and with soil moisture content, but negatively correlated with soil pH. The C:N ratios of different C and N pools were greater in the burned treatments than in the NB treatments. This study has highlighted that the prescribed burning at four year interval is a more sustainable management practice for this subtropical forest ecosystem. Copyright © 2015 Elsevier B.V. All rights reserved.

Does the presence of large down wood at the time of a forest fire impact soil recovery?

Treesearch

Jane E. Smith; Laurel A. Kluber; Tara N. Jennings; Donaraye McKay; Greg Brenner; Elizabeth W. Sulzman

2017-01-01

Fire may remove or create dead wood aboveground, but it is less clear how high severity burning of soils affects belowground microbial communities and soil processes, and for how long. In this study, we investigated soil fungal and bacterial communities and biogeochemical responses of severely burned ‘‘red” soil and less severely burned ‘‘black” soil from a burned...

In situ measurements of post-fire debris flows in southern California: Comparisons of the timing and magnitude of 24 debris-flow events with rainfall and soil moisture conditions

USGS Publications Warehouse

Kean, J.W.; Staley, D.M.; Cannon, S.H.

2011-01-01

Debris flows often occur in burned steeplands of southern California, sometimes causing property damage and loss of life. In an effort to better understand the hydrologic controls on post-fire debris-flow initiation, timing and magnitude, we measured the flow stage, rainfall, channel bed pore fluid pressure and hillslope soil-moisture accompanying 24 debris flows recorded in five different watersheds burned in the 2009 Station and Jesusita Fires (San Gabriel and Santa Ynez Mountains). The measurements show substantial differences in debris-flow dynamics between sites and between sequential events at the same site. Despite these differences, the timing and magnitude of all events were consistently associated with local peaks in short duration (< = 30 min) rainfall intensity. Overall, debris-flow stage was best cross-correlated with time series of 5-min rainfall intensity, and lagged the rainfall by an average of just 5 min. An index of debris-flow volume was also best correlated with short-duration rainfall intensity, but found to be poorly correlated with storm cumulative rainfall and hillslope soil water content. Post-event observations of erosion and slope stability modeling suggest that the debris flows initiated primarily by processes related to surface water runoff, rather than shallow landslides. By identifying the storm characteristics most closely associated with post-fire debris flows, these measurements provide valuable guidance for warning operations and important constraints for developing and testing models of post-fire debris flows. copyright. 2011 by the American Geophysical Union.

Long-term impacts of prescribed burns on soil thermal conductivity and soil heating at a Colorado Rocky Mountain site: a data/model fusion study

Treesearch

W. J. Massman; J. M. Frank; N. B. Reisch

2008-01-01

Heating any soil during a sufficiently intense wild fire or prescribed burn can alter that soil irreversibly, resulting in many significant, and well studied, long-term biological, chemical, and hydrological effects. On the other hand, much less is known about how fire affects the thermal properties and the long-term thermal regime of soils. Such knowledge is important...

Thermal alteration of soil organic matter properties: a systematic study to infer response of Sierra Nevada climosequence soils to forest fires

NASA Astrophysics Data System (ADS)

Araya, Samuel N.; Fogel, Marilyn L.; Asefaw Berhe, Asmeret

2017-02-01

Fire is a major driver of soil organic matter (SOM) dynamics, and contemporary global climate change is changing global fire regimes. We conducted laboratory heating experiments on soils from five locations across the western Sierra Nevada climosequence to investigate thermal alteration of SOM properties and determine temperature thresholds for major shifts in SOM properties. Topsoils (0 to 5 cm depth) were exposed to a range of temperatures that are expected during prescribed and wild fires (150, 250, 350, 450, 550, and 650 °C). With increase in temperature, we found that the concentrations of carbon (C) and nitrogen (N) decreased in a similar pattern among all five soils that varied considerably in their original SOM concentrations and mineralogies. Soils were separated into discrete size classes by dry sieving. The C and N concentrations in the larger aggregate size fractions (2-0.25 mm) decreased with an increase in temperature, so that at 450 °C the remaining C and N were almost entirely associated with the smaller aggregate size fractions ( < 0.25 mm). We observed a general trend of 13C enrichment with temperature increase. There was also 15N enrichment with temperature increase, followed by 15N depletion when temperature increased beyond 350 °C. For all the measured variables, the largest physical, chemical, elemental, and isotopic changes occurred at the mid-intensity fire temperatures, i.e., 350 and 450 °C. The magnitude of the observed changes in SOM composition and distribution in three aggregate size classes, as well as the temperature thresholds for critical changes in physical and chemical properties of soils (such as specific surface area, pH, cation exchange capacity), suggest that transformation and loss of SOM are the principal responses in heated soils. Findings from this systematic investigation of soil and SOM response to heating are critical for predicting how soils are likely to be affected by future climate and fire regimes.

Post-wildfire management effects on short-term evolution of soil properties (Catalonia, Spain, SW-Europe).

PubMed

Francos, Marcos; Pereira, Paulo; Alcañiz, Meritxell; Úbeda, Xavier

2018-08-15

Post-fire management practices after wildfires have an important impact on soil properties. Nevertheless, little research has been carried out. The aim of this study is to examine the impact of different post-wildfire forest management practices in a 10-month period immediately after a severe wildfire on soil properties. Two months after a wildfire, three experimental areas were designed, each one with different post-fire management: Cut and Remove (CR) where burned trunks were cut after fire and removed manually from the area; No Treatment (NT) where no intervention was carried out; and, Cut and Leave (CL) where burned trunks were cut and left randomly on topsoil. In each treatment, we collected nine samples (0-5cm deep). In total, we sampled 27 samples in each sampling date, two and ten months after the wildfire. The properties analyzed were aggregate stability (AS), total nitrogen (TN), soil organic matter (SOM), inorganic carbon (IC), C/N ratio, pH, electrical conductivity (EC), extractable calcium (Ca), magnesium (Mg), sodium (Na) and potassium (K). Soil C/N ratio was significantly higher in CR and CL treatments 10months after fire comparing to 2months after. On the other hand, pH, extractable Ca, Mg and K were significantly higher in all the treatments 2months after fire than 10months after. Aggregate stability, TN and SOM were significantly higher in CR comparing to CL, 10months after the fire. IC was significantly higher in CL than in NT treatment, also, 10months after the fire. Electrical conductivity was significantly higher in CR and CL treatments 2months after fire comparing to 10months after. According to the results, CR and CL post-fire management did not differ importantly from the NT scenario, showing that manual wood management does not have detrimental impacts on soil properties compared to mechanical operations. Copyright © 2018 Elsevier B.V. All rights reserved.

Effects of Fire on Understory Vegetation Communities in Siberian Boreal Forests and Alaskan Tundra

NASA Astrophysics Data System (ADS)

Pena, H., III; Alexander, H. D.; Natali, S.; Loranty, M. M.; Holmes, R. M.; Mack, M. C.; Schade, J. D.; Mann, P. J.; Davydov, S. P.; Frey, B.; Zimov, N.; Jardine, L. E.

2017-12-01

Fire is an important disturbance in Arctic ecosystems that is increasing in frequency and severity as a result of climate warming. Fire alters the landscape, changes soil conditions, and influences vegetation regrowth, favoring early-successional plants and those with well-established root systems capable of surviving fire. Post-fire vegetation establishment contributes to the recovery of the soil organic layer (SOL), which insulates the soil and protects soil and permafrost carbon pools. In order to better understand successional dynamics following fire in the Arctic we assessed the short-(years) and long-(decades) term effects of fire on vegetation communities, SOL depth, and thaw depth across fire-affected sites located in two regions of the Arctic- a 76-year old fire scar in a larch forest in Siberia near Cherskiy, Russia, and a 2-year old fire scar in tundra in the Yukon-Kuskokwim Delta, Alaska. We measured species diversity, plant carbon (C) pools, SOL conditions and NDVI at both study areas. As expected, there was a decline in vegetation C pools following fire in Alaskan tundra, and as a result of higher severity fire in Siberian boreal forests. Two years following fire in Alaskan tundra, vegetation C pools decreased six-fold from 600 g C m-2 at unburned areas, to 100 g C m-2 at the 2015 burn areas. In larch forests, understory C pools were three-times lower in stands with high intensity fires (135 g C m-2) compared to those with low intensity fires (415 g C m-2), due to the absence of dwarf birch (Betula nana). Our results illustrate how fire influences vegetation at both early and later stages of succession, which can have cascading effects on SOL development and permafrost integrity, with the potential for release of large C stocks that may further exacerbate climate warming.

The role of fire in the boreal carbon budget

USGS Publications Warehouse

Harden, J.W.; Trumbore, S.E.; Stocks, B.J.; Hirsch, A.; Gower, S.T.; O'Neill, K. P.; Kasischke, E.S.

2000-01-01

To reconcile observations of decomposition rates, carbon inventories, and net primary production (NPP), we estimated long-term averages for C exchange in boreal forests near Thompson, Manitoba. Soil drainage as defined by water table, moss cover, and permafrost dynamics, is the dominant control on direct fire emissions. In upland forests, an average of about 10-30% of annual NPP was likely consumed by fire over the past 6500 years since these landforms and ecosystems were established. This long-term, average fire emission is much larger than has been accounted for in global C cycle models and may forecast an increase in fire activity for this region. While over decadal to century times these boreal forests may be acting as slight net sinks for C from the atmosphere to land, periods of drought and severe fire activity may result in net sources of C from these systems.

A burning story: The role of fire in the history of life

USGS Publications Warehouse

Pausas, J.G.; Keeley, J.E.

2009-01-01

Ecologists, biogeographers, and paleobotanists have long thought that climate and soils controlled the distribution of ecosystems, with the role of fire getting only limited appreciation. Here we review evidence from different disciplines demonstrating that wildfire appeared concomitant with the origin of terrestrial plants and played an important role throughout the history of life. The importance of fire has waxed and waned in association with changes in climate and paleoatmospheric conditions. Well before the emergence of humans on Earth, fire played a key role in the origins of plant adaptations as well as in the distribution of ecosystems. Humans initiated a new stage in ecosystem fire, using it to make the Earth more suited to their lifestyle. However, as human populations have expanded their use of fire, their actions have come to dominate some ecosystems and change natural processes in ways that threaten the sustainability of some landscapes. ?? 2009 by American Institute of Biological Sciences.

The influence of fire on the radiocarbon signature and character of soil organic matter in the Siskiyou national forest, Oregon, USA

Treesearch

Katherine Heckman; John L. Campbell; Heath Powers; Beverly E. Law; Chris Swanston

2013-01-01

Forest fires contribute a significant amount of CO2 to the atmosphere each year, and CO2 emissions from fires are likely to increase under projected conditions of global climate change. In addition to volatilizing aboveground biomass and litter layers, forest fires have a profound effect on belowground carbon (C) pools and the cycling of soil organic matter as a whole...

Estimating post-fire organic soil depth in the Alaskan boreal forest using the Normalized Burn Ratio

Treesearch

D. Verbyla; R. Lord

2008-01-01

As part of a long-term moose browse/fire severity study, we used the Normalized Burn Ratio (NBR) with historic Landsat Thematic Mapper (TM) imagery to estimate fire severity from a 1983 wildfire in interior Alaska. Fire severity was estimated in the field by measuring the depth of the organic soil at 57 sites during the summer of 2006. Sites were selected for field...

Chapter 4. Predicting post-fire erosion and sedimentation risk on a landscape scale

USGS Publications Warehouse

MacDonald, L.H.; Sampson, R.; Brady, D.; Juarros, L.; Martin, Deborah

2000-01-01

Historic fire suppression efforts have increased the likelihood of large wildfires in much of the western U.S. Post-fire soil erosion and sedimentation risks are important concerns to resource managers. In this paper we develop and apply procedures to predict post-fire erosion and sedimentation risks on a pixel-, catchment-, and landscape-scale in central and western Colorado.Our model for predicting post-fire surface erosion risk is conceptually similar to the Revised Universal Soil Loss Equation (RUSLE). One key addition is the incorporation of a hydrophobicity risk index (HY-RISK) based on vegetation type, predicted fire severity, and soil texture. Post-fire surface erosion risk was assessed for each 90-m pixel by combining HYRISK, slope, soil erodibility, and a factor representing the likely increase in soil wetness due to removal of the vegetation. Sedimentation risk was a simple function of stream gradient. Composite surface erosion and sedimentation risk indices were calculated and compared across the 72 catchments in the study area.When evaluated on a catchment scale, two-thirds of the catchments had relatively little post-fire erosion risk. Steeper catchments with higher fuel loadings typically had the highest post-fire surface erosion risk. These were generally located along the major north-south mountain chains and, to a lesser extent, in west-central Colorado. Sedimentation risks were usually highest in the eastern part of the study area where a higher proportion of streams had lower gradients. While data to validate the predicted erosion and sedimentation risks are lacking, the results appear reasonable and are consistent with our limited field observations. The models and analytic procedures can be readily adapted to other locations and should provide useful tools for planning and management at both the catchment and landscape scale.

Prescribed Burning and Clear-Cutting Effects on Understory Vegetation in a Pinus canariensis Stand (Gran Canaria)

PubMed Central

Arévalo, José Ramón; García-Domínguez, Celia; Naranjo-Cigala, Agustín; Grillo, Federico

2014-01-01

Prescribed fires are a powerful tool for reducing fire hazards by decreasing amounts of fuel. The main objective is to analyze the effects of prescribed burning on the understory vegetation composition as well as on the soil characteristics of a reforested stand of Pinus canariensis. The study attempts to identify the effects of the preburning treatment of cutting understory vegetation on the floristic parameters of the vegetation community. This study was carried out for two years following a prescribed fire in a Canarian pine stand. Cutting and burning treatment affected species composition and increased diversity. Burnt and cut plots were characterized by a diverse array of herbaceous species and by a lower abundance of Teline microphylla (endemic legume), although burning apparently induced its germination. Cut treatment was more consistently differentiated from the control plots than burnt treatment. Soil K decreased after both treatments, pH slightly decreased after cutting, while P and Ca increased after fire. From an ecological point of view, prescribed burning is a better management practice than cutting the woody species of the understory. However, long-term studies would be necessary to evaluate the effects of fire intensity, season and frequency in which the prescribed burning is applied. PMID:25147839

Prescribed burning and clear-cutting effects on understory vegetation in a Pinus canariensis stand (Gran Canaria).

PubMed

Arévalo, José Ramón; Fernández-Lugo, Silvia; García-Domínguez, Celia; Naranjo-Cigala, Agustín; Grillo, Federico; Calvo, Leonor

2014-01-01

Prescribed fires are a powerful tool for reducing fire hazards by decreasing amounts of fuel. The main objective is to analyze the effects of prescribed burning on the understory vegetation composition as well as on the soil characteristics of a reforested stand of Pinus canariensis. The study attempts to identify the effects of the preburning treatment of cutting understory vegetation on the floristic parameters of the vegetation community. This study was carried out for two years following a prescribed fire in a Canarian pine stand. Cutting and burning treatment affected species composition and increased diversity. Burnt and cut plots were characterized by a diverse array of herbaceous species and by a lower abundance of Teline microphylla (endemic legume), although burning apparently induced its germination. Cut treatment was more consistently differentiated from the control plots than burnt treatment. Soil K decreased after both treatments, pH slightly decreased after cutting, while P and Ca increased after fire. From an ecological point of view, prescribed burning is a better management practice than cutting the woody species of the understory. However, long-term studies would be necessary to evaluate the effects of fire intensity, season and frequency in which the prescribed burning is applied.

Intensification of freeze-thaw cycles in the soil on post-fire alpine slopes of Mount Shirouma-dake, northern Japanese Alps central Japan

NASA Astrophysics Data System (ADS)

Sasaki, A.; Suzuki, K.

2016-12-01

This is the continuous study to clarify the geo-environmental changes on the post-fire alpine slopes of Mount Shirouma-dake in the Northern Japanese Alps. The fire occurred at May 9, 2009 on the alpine slopes of Mount Shirouma-dake, and the fire spread to the Pinus pumila communities and grasslands. Although the grass had a little damage by the fire, the P. pumila received nearly impact of the fire. In the P. pumila communities where the leaf burnt, forest floor is exposed and become easy to be affected by atmospheric condition such as rain, wind, snow, and etc. First, we observed condition of the micro-landforms on post-fire slopes repeatedly for seventh years after the fire. As the results of the observation, it is clear that remarkable changes of these micro-landforms have not occurred but some litters on the forest-floor in the fired P. pumila communities are flushed out to surroundings. The litter layer on the forest-floor in the fired P. pumila communities were 3-4 cm thick in August of 2011, but it became 0.5 cm thick in September of 2014. The P. pumila communities established on the slopes consists of angular and sub-angular gravel with openwork texture, which are covered by thin soil layer. On July of 2016, the litter layer almost entirely flushed out and surface of soil layer is exposed to atmosphere. In addition, we observe the ground temperature and soil moisture, under the fired P. pumila communities and the no fired P. pumila communities since October 2009, to find influence of the fire. The ground temperature sensors were installed into at 1 cm, 10 cm, and 40 cm depth. The soil moisture sensors were installed into at 1 cm and 10 cm depth. The 1 cm depth of the soil on the post-fire slopes, several times of diurnal freeze-thaw cycles occurred on October and November since 2011, but it had not occurred in 2009 and 2010. In particular, more than 20 times of diurnal freeze-thaw cycles occurred on freezing period of 2014. The diurnal freeze-thaw cycles continue to be increasing until thawing period of 2016. The period of seasonal frost at 10 cm and 40 cm depth on the post-fire slopes are extended for two weeks. Snowmelt water is especially thought to be act on re-freezing of post-fire slopes on thawing period. These thermal condition changes are triggered by decrease in the thickness of the litter layer on the fired P. pumila communities.

Prescribed burning effects on soil physical properties and soil water repellency in a steep chaparral watershed, southern California, USA

Treesearch

K.R. Hubbert; H.K. Preisler; P.M. Wohlgemuth; R.C. Graham; M.G. Narog

2006-01-01

Chaparral watersheds associated with Mediterranean-type climate are distributed over five regions of the world. Because brushland soils are often shallow with low water holding capacities, and are on slopes prone to erosion, disturbances such as fire can adversely affect their physical properties. Fire can also increase the spatial coverage of soil water repellency,...

Rapid response of soil fungal communities to low and high intensity fire

NASA Astrophysics Data System (ADS)

Smith, Jane E.; Cowan, Ariel D.; Reazin, Chris; Jumpponen, Ari

2016-04-01

Contemporary fires have created high-severity burn areas exceeding historical distributions in forests in the western United States. Until recently, the response of soil ecosystems to high intensity burns has been largely unknown. In complementary studies, we investigated the environmental effect of extreme soil heating, such that occurs with the complete combustion of large down wood during wildfires, on soil fungi and nutrients. We used TRFLP and next generation sequencing (Illumina MiSeq) to investigate the fungal communities. During the burning of large down wood, temperatures lethal to fungi were detected at 0-cm, 5-cm, and 10-cm depths in soils compared to 0-cm depth in soils receiving low intensity broadcast burns. We compared the soil fungal diversity in ten high intensity burned plots paired with adjacent low intensity burned plots before and one week after at 0-10 cm soil depth. Nonmetric Multidimensional Scaling (NMS) ordinations and analyses of taxon frequencies reveal a substantial community turnover and corresponding near complete replacement of the dominant basidiomycetes by ascomycetes in high intensity burns. These coarse-level taxonomic responses were primarily attributable to a few fire-responsive (phoenicoid) fungi, particularly Pyronema sp. and Morchella sp., whose frequencies increased more than 100-fold following high intensity burns. Pinus ponderosa seedlings planted one week post-burn were harvested after four months for EMF root tip analysis. We found: a) greater differences in soil properties and nutrients in high intensity burned soils compared to low intensity burned and unburned soils; b) no differences in EMF richness and diversity; and c) weak differences in community composition based on relative abundance between unburned and either burn treatments. These results confirm the combustion of large downed wood can alter the soil environment directly beneath it. However, an EMF community similar to low burned soils recolonized high burned soils within one growing season. Community results from both burn treatments suggest an increase in patchy spatial distribution of EMF. The importance of incorporating mixed fire effects in fuel management practices will help to provide EMF refugia for dry forest regeneration. Our studies highlight the strong and rapid fungal community responses to fires and differences among fires of different severities. We theorize that quick initiation of EMF recolonization is possible depending on the size of high burn patches, proximity of low and unburned soil, and survival of nearby hosts.

Ecological strategies in california chaparral: Interacting effects of soils, climate, and fire on specific leaf area

USGS Publications Warehouse

Anacker, Brian; Rajakaruna, Nishanta; Ackerly, David; Harrison, Susan; Keeley, Jon E.; Vasey, Michael

2011-01-01

Background: High values of specific leaf area (SLA) are generally associated with high maximal growth rates in resource-rich conditions, such as mesic climates and fertile soils. However, fire may complicate this relationship since its frequency varies with both climate and soil fertility, and fire frequency selects for regeneration strategies (resprouting versus seeding) that are not independent of resource-acquisition strategies. Shared ancestry is also expected to affect the distribution of resource-use and regeneration traits.Aims: We examined climate, soil, and fire as drivers of community-level variation in a key functional trait, SLA, in chaparral in California.Methods: We quantified the phylogenetic, functional, and environmental non-independence of key traits for 87 species in 115 plots.Results: Among species, SLA was higher in resprouters than seeders, although not after phylogeny correction. Among communities, mean SLA was lower in harsh interior climates, but in these climates it was higher on more fertile soils and on more recently burned sites; in mesic coastal climates, mean SLA was uniformly high despite variation in soil fertility and fire history.Conclusions: We conclude that because important correlations exist among both species traits and environmental filters, interpreting the functional and phylogenetic structure of communities may require an understanding of complex interactive effects.

Modeling and risk assessment for soil temperatures beneath prescribed forest fires

Treesearch

Haiganoush K. Preisler; Sally M. Haase; Stephen S. Sackett

2000-01-01

Prescribed fire is a management tool used by wildland resource management organizations in many ecosystems to reduce hazardous fuels and to achieve a host of other objectives. To study the effects of fire in naturally accumulating fuel conditions, the ambient soil temperature is monitored beneath prescribed burns. In this study we developed a stochastic model for...

The role of fire in management of watershed responses

Treesearch

Malcolm J. Zwolinski

2000-01-01

Hydrologic responses of watersheds are strongly related to vegetation and soil disturbances. Many of the storage and transfer components of the global hydrologic cycle are altered by the occurrence of fire. The major effect of fire on the hydrologic functioning of watersheds is the removal of vegetation and litter materials that protect the soil surface. Reductions in...

Prefire and postfire erosion of soil nutrients within a chaparral watershed

Treesearch

Jason P. de Koff; Robert C. Graham; Ken R. Hubbert; Peter M. Wohlgemuth

2006-01-01

Prescribed burns are an effective and increasingly popular strategy for inhibiting wildfires. The goal of this study was to characterize soil nutrient loss after a prescribed fire within a chaparral watershed in southern California. The study compared hillslope sediments for approximately 1 year before the fire with those during the year after the fire. Samples were...

Characterization of post-fire surface cover, soils, and burn severity at the Cerro Grande Fire, New Mexico, using hyperspectral and multispectral remote sensing

USGS Publications Warehouse

Kokaly, R.F.; Rockwell, B.W.; Haire, S.L.; King, T.V.V.

2007-01-01

Forest fires leave behind a changed ecosystem with a patchwork of surface cover that includes ash, charred organic matter, soils and soil minerals, and dead, damaged, and living vegetation. The distributions of these materials affect post-fire processes of erosion, nutrient cycling, and vegetation regrowth. We analyzed high spatial resolution (2.4??m pixel size) Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) data collected over the Cerro Grande fire, to map post-fire surface cover into 10 classes, including ash, soil minerals, scorched conifer trees, and green vegetation. The Cerro Grande fire occurred near Los Alamos, New Mexico, in May 2000. The AVIRIS data were collected September 3, 2000. The surface cover map revealed complex patterns of ash, iron oxide minerals, and clay minerals in areas of complete combustion. Scorched conifer trees, which retained dry needles heated by the fire but not fully combusted by the flames, were found to cover much of the post-fire landscape. These scorched trees were found in narrow zones at the edges of completely burned areas. A surface cover map was also made using Landsat Enhanced Thematic Mapper plus (ETM+) data, collected September 5, 2000, and a maximum likelihood, supervised classification. When compared to AVIRIS, the Landsat classification grossly overestimated cover by dry conifer and ash classes and severely underestimated soil and green vegetation cover. In a comparison of AVIRIS surface cover to the Burned Area Emergency Rehabilitation (BAER) map of burn severity, the BAER high burn severity areas did not capture the variable patterns of post-fire surface cover by ash, soil, and scorched conifer trees seen in the AVIRIS map. The BAER map, derived from air photos, also did not capture the distribution of scorched trees that were observed in the AVIRIS map. Similarly, the moderate severity class of Landsat-derived burn severity maps generated from the differenced Normalized Burn Ratio (dNBR) calculation had low agreement with the AVIRIS classes of scorched conifer trees. Burn severity and surface cover images were found to contain complementary information, with the dNBR map presenting an image of degree of change caused by fire and the AVIRIS-derived map showing specific surface cover resulting from fire.

Smouldering Subsurface Fires in the Earth System

NASA Astrophysics Data System (ADS)

Rein, Guillermo

2010-05-01

Smouldering fires, the slow, low-temperature, flameless form of combustion, are an important phenomena in the Earth system. These fires propagate slowly through organic layers of the forest ground and are responsible for 50% or more of the total biomass consumed during wildfires. Only after the 2002 study of the 1997 extreme haze event in South-East Asia, the scientific community recognised the environmental and economic threats posed by subsurface fires. This was caused by the spread of vast biomass fires in Indonesia, burning below the surface for months during the El Niño climate event. It has been calculated that these fires released between 0.81 and 2.57 Gton of carbon gases (13-40% of global emissions). Large smouldering fires are rare events at the local scale but occur regularly at a global scale. Once ignited, they are particularly difficult to extinguish despite extensive rains or fire-fighting attempts and can persist for long periods of time (months, years) spreading over very extensive areas of forest and deep into the soil. Indeed, these are the oldest continuously burning fires on Earth. Earth scientists are interested in smouldering fires because they destroy large amounts of biomass and cause greater damage to the soil ecosystem than flaming fires do. Moreover, these fires cannot be detected with current satellite remote sensing technologies causing inconsistencies between emission inventories and model predictions. Organic soils sustain smouldering fire (hummus, duff, peat and coal) which total carbon pool exceeds that of the world's forests or the atmosphere. This have important implications for climate change. Warmer temperatures at high latitudes are resulting in unprecedented permafrost thaw that is leaving large soil carbon pools exposed to fires. Because the CO2 flux from peat fires has been measured to be about 3000 times larger that the natural degradation flux, permafrost thaw is a risk for greater carbon release by fire and subsequently influence carbon-climate feedbacks. This presentation will revise the current knowledge on smouldering fires in the Earth system regarding ignition, spread patterns and emissions. It will explain the key differences between shallow and deep fires, and flaming fires.

Soils and nutrient considerations

Treesearch

Thomas H. DeLuca

2000-01-01

Fire suppression has resulted in a buildup of forest litter and an accumulation of organic nitrogen, and a decrease in available potassium. This has changed the historic structure of soils and their nutrient content. Studies at 15 sites in Montana have looked at a wide range of changes in soil productivity following prescribed fire. Results indicate obvious benefits to...

Fire effects on temperate forest soil C and N storage

Treesearch

Lucas E. Nave; Eric D. Vance; Christopher W. Swanston; Peter S. Curtis

2011-01-01

Temperate forest soils store globally significant amounts of carbon (C) and nitrogen (N). Understanding how soil pools of these two elements change in response to disturbance and management is critical to maintaining ecosystem services such as forest productivity, greenhouse gas mitigation, and water resource protection. Fire is one of the principal disturbances acting...

Vulnerability of North American Boreal Peatlands to Interactions between Climate, Hydrology, and Wildland Fires

NASA Astrophysics Data System (ADS)

Bourgeau-Chavez, L. L.; Jenkins, L. K.; Kasischke, E. S.; Turetsky, M.; Benscoter, B.; Banda, E. J.; Boren, E. J.; Endres, S. L.; Billmire, M.

2013-12-01

North American boreal peatland sites of Alaska, Alberta Canada, and the southern limit of the boreal ecoregion (Michigan's Upper Peninsula) are the focus of an ongoing project to better understand the fire weather, hydrology, and climatic controls on boreal peatland fires. The overall goal of the research project is to reduce uncertainties of the role of northern high latitude ecosystems in the global carbon cycle and to improve carbon emission estimates from boreal fires. Boreal peatlands store tremendous reservoirs of soil carbon that are likely to become increasingly vulnerable to fire as climate change lowers water tables and exposes C-rich peat to burning. Increasing fire activity in peatlands could cause these ecosystems to become net sources of C to the atmosphere, which is likely to have large influences on atmospheric carbon concentrations through positive feedbacks that enhance climate warming. Remote sensing is key to monitoring, understanding and quantifying changes occurring in boreal peatlands. Remote sensing methods are being developed to: 1) map and classify peatland cover types; 2) characterize seasonal and inter-annual variations in the moisture content of surface peat (fuel) layers; 3) map the extent and seasonal timing of fires in peatlands; and 4) discriminate different levels of fuel consumption/burn severity in peat fires. A hybrid radar and optical infrared methodology has been developed to map peatland types (bog vs. fen) and level of biomass (open herbaceous, shrubby, forested). This methodology relies on multi-season data to detect phenological changes in hydrology which characterize the different ecosystem types. Landsat data are being used to discriminate burn severity classes in the peatland types using standard dNBR methods as well as individual bands. Cross referencing the peatland maps and burn severity maps will allow for assessment of the distribution of upland and peatland ecosystems affected by fire and quantitative analysis of emissions. Radar imagery from multiple platforms (L-band PALSAR, C-band ERS-2, Envisat, and Radarsat-2) is being used to develop soil moisture extraction algorithms to monitor changes (drying - wetting) through time and to develop a standard method for soil moisture assessment. Using data from the 1990s (ERS-1 and 2) through the present (Radarsat-2) will allow for determination of patterns of wetting and drying across the landscape. All the remote sensing analysis is supported with field work which has been coordinated with that of Canadian scientists. Field collection includes vegetation and hydrology data to validate peatland distribution maps, collection of water table depths and peat moisture content data to aid in algorithm development for radar organic soil moisture retrieval, and characterization of variations in depth of burning and carbon consumption during peatland fires to use in burn severity mapping and fire emissions modeling.

Burning transformations: Fire history effects on organic matter processing from hillslopes to streams

NASA Astrophysics Data System (ADS)

Barnes, R. T.; Gilbertson, A.; Maxwell, K.

2017-12-01

Disturbance strongly regulates material and energy flows, changing ecosystem pattern and process. An increase in the size and severity of fire, particularly in the Intermountain West, over the last several decades is expected to continue due to a warming climate. Predicting how fire will alter the net ecosystem carbon balance requires us to understand how carbon is stored, processed, and transferred. Here we present results from paired watersheds focused on five 2002 severe fires in Colorado to examine how organic matter is processed along the hillslope and within the stream. Comparing soil samples and water extractable organic matter (WEOM) between burned and unburned sites illustrates the impact of fire: burned soils have 50% organic matter (OM) content as unburned soils, regardless of geomorphic position. While a smaller pool, soil OM (SOM) in burned sites is more susceptible to microbial degradation (p<0.001 for 4 of 6 sites), especially in systems with slower vegetative recovery. This is explained, in part, to the water extractable organic matter (WEOM) from unburned soils having a higher C:N than burned sites (p<0.02). This shift in SOM quality is likely due to differing OM inputs (e.g. grasses and forbes vs. trees in burned vs. unburned sites). Comparing results from intact soil column experiments to soil extractions and stream samples, suggests that the majority of this soil derived WEOM does not make it to the stream, potentially getting sorbed deeper in the mineral rich, organic poor, portion of the soil. Interestingly, the systematic shifts in OM amounts and quality (as measured by SUVA, E2:E3, and fluorescence) within the terrestrial system in response to fire, are not seen in stream exports. As such, while there are significant relationships (p<0.05) between stream DOM quality, DOM bioavailability, and stream metabolism, burned watersheds are not exporting DOM that is more bioavailable. In addition, despite different terrestrial OM pools, burned and unburned watersheds export statistically similar amounts of DOM per unit area, suggesting that a larger fraction of OM is transferred from the terrestrial to aquatic ecosystem within fire affected landscapes.

Physical characteristics, chemical composition and water contamination potential from Canadian wildfire ash

NASA Astrophysics Data System (ADS)

Santin, Cristina; Doerr, Stefan; Arcenegui, Vicky; Otero, Xose Luis

2017-04-01

Wildland fires leave a powdery residue on the ground: wildfire ash, which consists of mineral materials and charred organic components. Its quantities and characteristics depend mainly on the total amount and type of fuel burnt and the fire characteristics. Up to several tens of tons of ash per hectare have been quantified in different post-fire environments. As a new material present after a wildland fire, ash can have profound effects on ecosystems. It affects biogeochemical cycles, including the carbon cycle, stimulates microbial activity and helps the recovery of vegetation. Ash incorporated into the soil increases soil pH and nutrient pools temporarily and changes soil physical properties such as albedo, soil texture and hydraulic properties. Ash also modifies soil and landscape-scale hydrological behaviour. Its high porosity makes it very effective at absorbing rainfall, but it can also contribute to catastrophic debris flows when ash is mobilised by large storm events. Its 'fragile' nature makes ash very susceptible to wind and water erosion, facilitating its transfer to the hydrological system. Runoff containing ash from burnt areas carries soluble nutrients and pollutants, which can have detrimental impacts on aquatic ecosystems and the supply of potable water. In this presentation we will report for the first time on the physical characteristics, chemical composition and associated water pollution risk from ash produced in four typical Canadian boreal forest fires: two high-intensity fires in jack pine stands, and one high-intensity and one smouldering fire in black spruce stands.

Does the presence of large down wood at the time of a forest fire impact soil recovery?

DOE PAGES

Smith, Jane E.; Kluber, Laurel A.; Jennings, Tara N.; ...

2017-02-23

Fire may remove or create dead wood aboveground, but it is less clear how high severity burning of soils affects belowground microbial communities and soil processes, and for how long. Here, we investigated soil fungal and bacterial communities and biogeochemical responses of severely burned red soil and less severely burned black soil from a burned forest on the eastern slope of the Cascade Range in Oregon. We examined the effects of burn severity on soil nutrients and microbial communi- ties for 14 years after wildfire. Soil nutrients were significantly reduced in red soils. Soil fungi and bac teria, assessed withmore » molecular methods, steadily colonized both burn severities and soil biodiversity increased throughout the study showing that microbial communities seem to have the capacity to quickly adjust to extreme disturbances. Although richness did not vary by soil type, the fungal and bacterial community compositions varied with burn severity. This difference was greatest in the early time points following the fire and decreased with time. But, nutrient-limited conditions of red soils were detected for four years after the wildfire and raise concern about soil productivity at these sites.« less

Does the presence of large down wood at the time of a forest fire impact soil recovery?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Jane E.; Kluber, Laurel A.; Jennings, Tara N.

Fire may remove or create dead wood aboveground, but it is less clear how high severity burning of soils affects belowground microbial communities and soil processes, and for how long. Here, we investigated soil fungal and bacterial communities and biogeochemical responses of severely burned red soil and less severely burned black soil from a burned forest on the eastern slope of the Cascade Range in Oregon. We examined the effects of burn severity on soil nutrients and microbial communi- ties for 14 years after wildfire. Soil nutrients were significantly reduced in red soils. Soil fungi and bac teria, assessed withmore » molecular methods, steadily colonized both burn severities and soil biodiversity increased throughout the study showing that microbial communities seem to have the capacity to quickly adjust to extreme disturbances. Although richness did not vary by soil type, the fungal and bacterial community compositions varied with burn severity. This difference was greatest in the early time points following the fire and decreased with time. But, nutrient-limited conditions of red soils were detected for four years after the wildfire and raise concern about soil productivity at these sites.« less

Soil data from fire and permafrost-thaw chronosequences in upland Picea mariana stands near Hess Creek and Tok, interior Alaska

USGS Publications Warehouse

O'Donnell, Jonathan A.; Harden, Jennifer W.; Manies, Kristen L.; Jorgenson, M. Torre; Kanevskiy, Mikhail; Xu, Xiaomei

2013-01-01

Soils of the Northern Circumpolar Permafrost region harbor 1,672 petagrams (Pg) (1 Pg = 1,000,000,000 kilograms) of organic carbon (OC), nearly 50 percent of the global belowground OC pool (Tarnocai and others, 2009). Of that soil OC, nearly 88 percent is presently stored in perennially frozen ground. Recent climate warming at northern latitudes has resulted in warming and thawing of permafrost in many regions (Osterkamp, 2007), which might mobilize OC stocks from associated soil reservoirs via decomposition, leaching, or erosion. Warming also has increased the magnitude and severity of wildfires in the boreal region (Turetsky and others, 2011), which might exacerbate rates of permafrost degradation relative to warming alone. Given the size and vulnerability of the soil OC pool in permafrost soils, permafrost thaw will likely function as a strong positive feedback to the climate system (Koven and others, 2011; Schaefer and others, 2011). In this report, we report soil OC inventories from two upland fire chronosequences located near Hess Creek and Tok in Interior Alaska. We sampled organic and mineral soils in the top 2 meters (m) across a range of stand ages to evaluate the effects of wildfire and permafrost thaw on soil C dynamics. These data were used to parameterize a simple process-based fire-permafrost-carbon model, which is described in detail by O’Donnell and others (2011a, b). Model simulations examine long-term changes in soil OC storage in response to fire, permafrost thaw, and climate change. These data also have been used in other papers, including Harden and others (2012), which examines C recovery post-fire, and Johnson and others (2011), which synthesizes data within the Alaska Soil Carbon Database. Findings from these studies highlight the importance of climate and disturbance (wildfire, permafrost thaw) on soil C storage, and loss of soil C from high-latitude ecosystems.

Fort Collins Science Center: Ecosystem Dynamics

USGS Publications Warehouse

Bowen, Zack

2004-01-01

Current studies fall into five general areas. Herbivore-Ecosystem Interactions examines the efficacy of multiple controls on selected herbivore populations and cascading effects through predator-herbivore-plant-soil linkages. Riparian Ecology is concerned with interactions among streamflow, fluvial geomorphology, and riparian vegetation. Integrated Fire Science focuses on the effects of fire on plant and animal communities at multiple scales, and on the interactions between post-fire plant, runoff, and erosion processes. Reference Ecosystems comprises long-term, place-based studies of ecosystem biogeochemistry. Finally, Integrated Assessments is investigating how to synthesize multiple ecosystem stressors and responses over complex landscapes in ways that are useful for management and planning.

Linear Modeling and Evaluation of Controls on Flow Response in Western Post-Fire Watersheds

NASA Astrophysics Data System (ADS)

Saxe, S.; Hogue, T. S.; Hay, L.

2015-12-01

This research investigates the impact of wildfires on watershed flow regimes throughout the western United States, specifically focusing on evaluation of fire events within specified subregions and determination of the impact of climate and geophysical variables in post-fire flow response. Fire events were collected through federal and state-level databases and streamflow data were collected from U.S. Geological Survey stream gages. 263 watersheds were identified with at least 10 years of continuous pre-fire daily streamflow records and 5 years of continuous post-fire daily flow records. For each watershed, percent changes in runoff ratio (RO), annual seven day low-flows (7Q2) and annual seven day high-flows (7Q10) were calculated from pre- to post-fire. Numerous independent variables were identified for each watershed and fire event, including topographic, land cover, climate, burn severity, and soils data. The national watersheds were divided into five regions through K-clustering and a lasso linear regression model, applying the Leave-One-Out calibration method, was calculated for each region. Nash-Sutcliffe Efficiency (NSE) was used to determine the accuracy of the resulting models. The regions encompassing the United States along and west of the Rocky Mountains, excluding the coastal watersheds, produced the most accurate linear models. The Pacific coast region models produced poor and inconsistent results, indicating that the regions need to be further subdivided. Presently, RO and HF response variables appear to be more easily modeled than LF. Results of linear regression modeling showed varying importance of watershed and fire event variables, with conflicting correlation between land cover types and soil types by region. The addition of further independent variables and constriction of current variables based on correlation indicators is ongoing and should allow for more accurate linear regression modeling.

Restoring fire as an ecological process in shortgrass prairie ecosystems: initial effects of prescribed burning during the dormant and growing seasons.

PubMed

Brockway, Dale G; Gatewood, Richard G; Paris, Randi B

2002-06-01

Prior to Anglo-European settlement, fire was a major ecological process influencing the structure, composition and productivity of shortgrass prairie ecosystems on the Great Plains. However during the past 125 years, the frequency and extent of grassland fire has dramatically declined as a result of the systematic heavy grazing by large herds of domestic cattle and sheep which reduced the available levels of fine fuel and organized fire suppression efforts that succeeded in altering the natural fire regime. The greatly diminished role of recurrent fire in these ecosystems is thought to be responsible for ecologically adverse shifts in the composition, structure and diversity of these grasslands, leading specifically to the rise of ruderal species and invasion by less fire-tolerant species. The purpose of this study was to evaluate the ecological effects of fire season and frequency on the shortgrass prairie and to determine the means by which prescribed fire can best be restored in this ecosystem to provide the greatest benefit for numerous resource values. Plant cover, diversity, biomass and nutrient status, litter cover and soil chemistry were measured prior to and following fire treatments on a buffalograss-blue grama shortgrass prairie in northeastern New Mexico. Dormant-season fire was followed by increases in grass cover, forb cover, species richness and concentrations of foliar P, K, Ca, Mg and Mn. Growing-season fire produced declines in the cover of buffalograss, graminoids and forbs and increases in litter cover and levels of foliar P, K, Ca and Mn. Although no changes in soil chemistry were observed, both fire treatments caused decreases in herbaceous production, with standing biomass resulting from growing-season fire approximately 600 kg/ha and dormant-season fire approximately 1200 kg/ha, compared with controls approximately 1800 kg/ha. The initial findings of this long-term experiment suggest that dormant-season burning may be the preferable method for restoring fire in shortgrass prairie ecosystems where fire has been excluded for a prolonged time period.

Can compost improve Quercus pubescens Willd establishment in a Mediterranean post-fire shrubland?

PubMed

Larchevêque, Marie; Montès, Nicolas; Baldy, Virginie; Ballini, Christine

2008-06-01

The aim of the study was to evaluate the effects of sewage sludge compost (control, 20 kg m(-2), 40 kg m(-2)) supplied to Quercus pubescens Willd seedlings planted in a post-fire calcareous site in Provence (France). Changes in soil properties, seedling survival, growth and nutrition were monitored 7 months, 1.5 years and 2.5 years after amendment, and possible trace metal contamination of soil and seedlings by compost was also evaluated. Compost improved overall soil fertility by increasing organic matter, cation exchange capacity, total N and exchangeable P, K, Mg and B concentrations, but 40 kg m(-2) induced a more significant and more durable effect than 20 kg m(-2). However, the compost had no effect on seedling survival and growth, but increased foliar P and B concentrations at 40 kg m(-2). No foliar contamination of seedlings by trace metals occurred, although amendment increased exchangeable Cu and Zn concentrations in soil. Compost P and exchangeable Cu and Zn concentrations could induce eutrophication and water pollution, and limit rates that can be applied without environmental hazard.

Carbon Burn-Down in a Greenhouse World: Wildfires and Soil Carbon Loss across the Paleocene-Eocene Thermal Maximum (PETM)

NASA Astrophysics Data System (ADS)

Denis, E. H.; Foreman, B.; Maibauer, B.; Bowen, G. J.; Collinson, M. E.; Belcher, C.; Freeman, K. H.

2014-12-01

Projections for Earth's future suggest that wildfire activity will increase with global warming, but the factors controlling fire are complex. The Paleocene-Eocene Thermal Maximum (PETM) was a geologically abrupt global warming event that had profound effects on vegetation and hydrologic patterns and serves as an analog for modern climate change. Carbon burn-down (i.e., oxidation of organic matter) could amplify feedbacks with warming through release of carbon to the atmosphere. To assess relationships between climate, fire and soil respiration, we evaluated biomarkers, including polycyclic aromatic hydrocarbons (PAHs), charcoal and total organic carbon (TOC) for three paleo-floodplain depositional sites in the Western USA. Samples were selected from Bighorn Basin Coring Project cores in the Bighorn Basin, Wyoming (at Basin Substation and Polecat Bench) and from an outcrop section in the Piceance Basin, Colorado. In general, the Paleocene had higher PAH concentrations (μg/g TOC) than the Eocene, but there was no clear trend during the onset (~20 kyr) or through the PETM (~200 kyr). Median %TOC decreased through the PETM, then increased in the Eocene, but did not return to Paleocene values. At Basin Substation, PAH concentrations decreased by an order of magnitude during the PETM interval, concurrent with a decline in TOC and charcoal. High molecular weight (MW) PAHs tend to dominate, especially in low TOC samples; this suggests preferential loss of low MW PAHs, which are relatively more susceptible to post-depositional processes. Lithology, TOC and the relative proportion of PAHs help discern the signals of carbon oxidation, by fire and by soil respiration. Despite climate conditions that tend to promote fire, there is no evidence for increased fires at the onset or throughout the PETM. Biomarker and petrographic data suggest decreased organic carbon preservation, including loss of refractory carbon, at Basin Substation during the PETM. This suggests soil carbon loss, possibly due to higher rates of organic matter decay associated with a hotter and more seasonal climate during the PETM. We propose that higher carbon burn-down, due to accelerated decay rates, outpaced terrestrial productivity during the hyperthermal event, which hindered soil carbon sequestration and enhanced the atmospheric greenhouse.

Response of respiration and nutrient availability to drying and rewetting in soil from a semi-arid woodland depends on vegetation patch and a recent wild fire

NASA Astrophysics Data System (ADS)

Sun, Q.; Meyer, W. S.; Koerber, G.; Marschner, P.

2015-06-01

Semi-arid woodlands, which are characterised by patchy vegetation interspersed with bare, open areas, are frequently exposed to wild fire. During summer, long dry periods are occasionally interrupted by rainfall events. It is well-known that rewetting of dry soil induces a flush of respiration. However, the magnitude of the flush may differ between vegetation patches and open areas because of different organic matter content which could be further modulated by wild fire. Soils were collected from under trees, under shrubs or in open areas in unburnt and burnt sandy Mallee woodland, where part of the woodland experienced a wild fire which destroyed or damaged most of the aboveground plant parts four months before sampling. In an incubation experiment, the soils were exposed to two moisture treatments: constantly moist (CM) and drying and rewetting (DRW). In CM, soils were incubated at 80% of maximum water holding capacity for 19 days; In DRW, soils were dried for four days, kept dry for another five days, then rewet to 80% WHC and maintained at this water content until day 19. Soil respiration decreased during drying and was very low in the dry period; rewetting induced a respiration flush. Compared to soil under shrubs and in open areas, cumulative respiration per g soil in CM and DRW was greater under trees, but lower when expressed per g TOC. Organic matter content, available P, and microbial biomass C, but not available N were greater under trees than in open areas. Wild fire decreased the flush of respiration per g TOC in the open areas and under shrubs, and reduced TOC and MBC concentrations only under trees, but had little effect on available N and P concentrations. We conclude that of the impact wild fire and DRW events on nutrient cycling differ among vegetation patches of a native semiarid woodland which is related to organic matter amount and availability.

Mitigation of water repellency in burned soils applying hydrophillic polymers

NASA Astrophysics Data System (ADS)

Neris, Jonay; de la Torre, Sara; Vidal-Vazquez, Eva; Lado, Marcos

2017-04-01

In this study, the effect of fire on water repellency was analyzed in soils from different parent materials, as well as the suitability of anionic polyacrylamide (PAM) to reduce water repellency in these soils. Samples were collected in four different sites where wildfires took place: two in the Canary Islands, with soils developed on volcanic materials, and two in Galicia (NW Spain), with soils developed on plutonic rocks. In Galicia, two soil samples were collected in each site, one in the burnt area and one in an adjacent unburnt area. In the Canary Islands, four samples were collected from each site, three inside the burnt area where the soils were affected by different fire intensities, and one in an unburnt adjacent area. Samples were air-dried and sieved by a 2-mm mesh sieve. Water repellency was measured using the Water Drop Penetration Time test. An amount of 10 g of soil was placed in a tray. Five drops of deionized water were place on the soil surface with a pipette, and the time for each drop to fully penetrate into the soil was recorded. PAM solution was applied to the burnt soils simulating a field application rate of 1gm-2. The polymer used was Superfloc A-110 (Kemira Water Solutions BV, Holland) with 1x107 Da molecular weigth and 15% hydrolysis. PAM was sprayed on the soil surface as solution with a concentration 0.2 g/L. After the application, the samples were dried and the WDPT test was performed. Three replicates for each treatment and soil were used, and the treatments included: dry soil, dry soil after a wetting treatment, dry PAM-treated soil. The results showed that water repellency was modified by fire differently in the various soils. In hydrophilic soils and soils with low water repellency, water repellency was increased after the action of fire. In soils with noticeable initial water repellency, this was reduced or eliminated after the fire. Wetting repellent soils caused a decrease in water repellency most probably because of the spatial redistribution of hydrophobic organic compounds that caused water repellency. The addition of PAM further reduced in all of the cases. The application of PAM could be an effective method for mitigation of water repellency in burnt soils.

A non-equilibrium model for soil heating and moisture transport during extreme surface heating: The soil (heat-moisture-vapor) HMV-Model Version

Treesearch

William Massman

2015-01-01

Increased use of prescribed fire by land managers and the increasing likelihood of wildfires due to climate change require an improved modeling capability of extreme heating of soils during fires. This issue is addressed here by developing and testing the soil (heat-moisture-vapor) HMVmodel, a 1-D (one-dimensional) non-equilibrium (liquid- vapor phase change)...

Predicting the effectiveness of different mulching techniques to reduce post-fire runoff and erosion in Mediterranean pine stands - does cover matter?

NASA Astrophysics Data System (ADS)

Vieira, Diana; Nunes, João; Prats, Sergio; Serpa, Dalila; Keizer, Jan

2016-04-01

Wildfires have become a recurrent threat for many forest ecosystems of the Mediterranean. The characteristics of the Mediterranean climate with its warm and dry summers and mild and wet winters make it prone to wildfire occurrence as well as to post-fire soil erosion. Furthermore, climate change and continuation of current land management practices and planning are generally expected to further increase this threat. The wide recognition of the effects of wildfires to enhance runoff and erosion has created a strong demand for model-based tools for predicting the post-fire hydrological and erosion response and, in particular, for predicting the effectiveness of post-fire forestry operations to mitigate these responses. Such a tool should allow to identify areas with elevated risks of soil erosion and to evaluate which measures should be applied and when to minimize these risks. A key element in evaluating these measures is also their costs, in order to optimize the use of the limited resources that are typically available for post-fire land management. In this study, two "treatments" are compared with control conditions (i.e. doing nothing) after a wildfire with a moderate soil burn severity: (i) 4 erosion plots were treated with hydro-mulch, (ii) 4 erosion plots were untreated but had a high pine needle cover quickly after the fire, due to needle cast from scorched pine crowns (often referred to as "natural mulching") (iii) 4 plots were untreated and had a very reduced protective litter cover . The main objective of this study was to asses if the revised MMF model could effectively predict the impacts of hydro-mulching and natural mulching with pine needle on runoff generation and the associated soil losses. If MMF could predict well the impact of natural mulching, it could be very useful in limiting the areas that should be considered for specific soil mitigation measures, especially in the case of wildfires that affect large areas with moderate severity. The revised MMF model allowed, in fact, accurate predictions of runoff and soil erosion over the first year following hydro-mulch application . The obtained efficiency indices (Nash Sutcliffe Efficiency) of 0.82 and 0.71 for runoff and erosion, respectively, suggested that the revised MMF model could be at the base of a tool to assist decision-making in post-fire forest management. Furthermore, the MMF results obtained for hydro-mulching agreed well with those obtained in a previous study in the region for mulching with forest residues (Vieira et al., 2014). Ongoing work is assessing the possible improvements in model predictions by applying MMF on a seasonal basis and/or taking into account the occurrence of soil water repellency, i.e. using the adjustments of MMF to post-fire conditions as proposed in Vieira et al. (2014) and so far only tested - successfully - for eucalypt plantations in the study region. Vieira DCS, Prats SA, Nunes JP, Shakesby RA, Coelho COA, Keizer JJ (2014) Modelling runoff and erosion, and their mitigation, in burned Portuguese forest using the revised Morgan-Morgan-Finney model. Forest Ecology and Management 314: 150-165

A Simple Field Guides to Identify Fire Effects on Soils

NASA Astrophysics Data System (ADS)

Robichaud, Peter

2016-04-01

Following wildfires post fire assessment personnel or teams assess immediate post-fire watershed conditions. These assessment teams must determine threats from flooding, soil erosion, and instability in a relatively short time period. Various tools and guides have been developed to assist in that process. A soil burn severity map is often the first step in the rapid assessment process. It enables BAER teams to prioritize field reviews and locate burned areas that may pose a risk to critical values within or downstream of the burned area. Five field parameters are easily determined in the field 1) remaining ground cover and characteristic, 2) ash color and depth, 3) soil structure, 4) fine roots, and 5) soil water repellency. All parameters are visual identified except water repellency which can be determined by the Water Drop Penetration Time (WDPT) test or Mini-Disk Infiltrometer (MDI). Often times the MDI test takes less time, is less subjective, and provides a relative infiltration rate which the WDPT test does not. The MDI test results are often put into "degree of soil water repellency" categories (strong, weak, and none). These field procedures that indicate the fire effects on the soil conditions help assessment teams consistently interpret, field validate and map soil burn severity.

Physical Processes Dictate Early Biogeochemical Dynamics of Soil Pyrogenic Organic Matter in a Subtropical Forest Ecosystem

NASA Astrophysics Data System (ADS)

Stuart, Jason M.; Anderson, Russell; Lazzarino, Patrick; Kuehn, Kevin A.; Harvey, Omar R.

2018-05-01

Quantifying links between pyOM dynamics, environmental factors and processes is central to predicting ecosystem function and response to future perturbations. In this study, changes in carbon (TC), nitrogen (TN) , pH and relative recalcitrance (R50) for pine- and cordgrass-derived pyOM were measured at 3-6 weeks intervals throughout the first year of burial in the soil. Objectives were to 1) identify key environmental factors and processes driving early-stage pyOM dynamics, and 2) develop quantitative relationships between environmental factors and changes in pyOM properties. The study was conducted in sandy soils of a forested ecosystem in the Longleaf pine range, US with a focus on links between changes in pyOM properties, fire history (FH), cumulative precipitation (Pcum), average temperature (Tavg) and soil residence time (SRT). Pcum, SRT and Tavg were the main factors controlling TC and TN accounting for 77-91% and 64-96% of their respective variability. Fire history, along with Pcum, SRT and Tavg, exhibited significant controlling effects on pyOM, pH and R50 - accounting for 48-91% and 88-93% of respective variability. Volatilization of volatiles and leaching of water-soluble components (in summer) and the sorption of exogenous organic matter (fall through spring) were most plausibly controlling pyOM dynamics in this study. Overall, our results point to climatic and land management factors and physicochemical process as the main drivers of pyOM dynamics in the pine ecosystems of the Southeastern US.

Environmental factors affecting corrosion of munitions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bundy, K.; Bricka, M.; Morales, A.

1995-12-31

Spent small arms munitions have accumulated for years at outdoor firing ranges operated by the DoD and other groups. Used bullets are often subjected to moisture sources. There is increasing concern that accumulations of lead-based munitions represent potential sources of water and soil pollution. To understand both the severity of and solutions to this problem, it is necessary to measure how rapidly bullets corrode and to determine the soil variables affecting the process. In this study M16 bullets were buried in samples of soil taken from Louisiana army firing ranges. Four environmental conditions were simulated; rain water, acid rain, seamore » water, and 50% sea water/50% acid rain. The three electrode technique was used to measure the bullet corrosion. Graphite rods served as counter electrodes. A saturated calomel reference electrode was used along with a specially constructed salt bridge. Electrochemical measurements were conducted using a computer-controlled potentiostat to determine corrosion potential, soil resistance, and corrosion current. The rate of corrosion was found to markedly increase with decreasing soil pH and increasing chloride and moisture contents, with the chloride content being the most influential variable. High soil resistance and noble corrosion potential were found to be associated with low corrosion rates. This is important since both parameters can be readily measured in the field.« less

Spatial Patterns of Soil Respiration Links Above and Belowground Processes along a Boreal Aspen Fire Chronosequence

PubMed Central

Das Gupta, Sanatan; Mackenzie, M. Derek

2016-01-01

Fire in boreal ecosystems is known to affect CO2 efflux from forest soils, which is commonly termed soil respiration (Rs). However, there is limited information on how fire and recovery from this disturbance affects spatial variation in Rs. The main objective of this study was to quantify the spatial variability of Rs over the growing season in a boreal aspen (Populus tremuloides Michx.) fire chronosequence. The chronosequence included three stands in northern Alberta; a post fire stand (1 year old, PF), a stand at canopy closure (9 years old, CC), and a mature stand (72 years old, MA). Soil respiration, temperature and moisture were measured monthly from May to August using an intensive spatial sampling protocol (n = 42, minimum lag = 2 m). Key aboveground and belowground properties were measured one time at each sampling point. No spatial structure was detected in Rs of the PF stand during the peak growing season (June and July), whereas Rs was auto-correlated at a scale of < 6 m in the CC and MA stands. The PF stand had the lowest mean Rs (4.60 μmol C m-2 s-1) followed by the CC (5.41 μmol C m-2 s-1), and the MA (7.32 μmol C m-2 s-1) stand. Forest floor depth was the only aboveground factor that influenced the spatial pattern of Rs in all three stands and was strongest in the PF stand. Enzyme activity and fine root biomass, on the other hand, were the significant belowground factors driving the spatial pattern of Rs in the CC and MA stands. Persistent joint aboveground and belowground control on Rs in the CC and MA stands indicates a tight spatial coupling, which was not observed in the PF stand. Overall, the current study suggests that fire in the boreal aspen ecosystem alters the spatial structure of Rs and that fine scale heterogeneity develops quickly as stands reach the canopy closure phase (<10 years). PMID:27832089

Spatial Patterns of Soil Respiration Links Above and Belowground Processes along a Boreal Aspen Fire Chronosequence.

PubMed

Das Gupta, Sanatan; Mackenzie, M Derek

2016-01-01

Fire in boreal ecosystems is known to affect CO2 efflux from forest soils, which is commonly termed soil respiration (Rs). However, there is limited information on how fire and recovery from this disturbance affects spatial variation in Rs. The main objective of this study was to quantify the spatial variability of Rs over the growing season in a boreal aspen (Populus tremuloides Michx.) fire chronosequence. The chronosequence included three stands in northern Alberta; a post fire stand (1 year old, PF), a stand at canopy closure (9 years old, CC), and a mature stand (72 years old, MA). Soil respiration, temperature and moisture were measured monthly from May to August using an intensive spatial sampling protocol (n = 42, minimum lag = 2 m). Key aboveground and belowground properties were measured one time at each sampling point. No spatial structure was detected in Rs of the PF stand during the peak growing season (June and July), whereas Rs was auto-correlated at a scale of < 6 m in the CC and MA stands. The PF stand had the lowest mean Rs (4.60 μmol C m-2 s-1) followed by the CC (5.41 μmol C m-2 s-1), and the MA (7.32 μmol C m-2 s-1) stand. Forest floor depth was the only aboveground factor that influenced the spatial pattern of Rs in all three stands and was strongest in the PF stand. Enzyme activity and fine root biomass, on the other hand, were the significant belowground factors driving the spatial pattern of Rs in the CC and MA stands. Persistent joint aboveground and belowground control on Rs in the CC and MA stands indicates a tight spatial coupling, which was not observed in the PF stand. Overall, the current study suggests that fire in the boreal aspen ecosystem alters the spatial structure of Rs and that fine scale heterogeneity develops quickly as stands reach the canopy closure phase (<10 years).

Effects of prescribed fire in giant sequoia-mixed conifer stands in Sequoia and Kings Canyon National Parks

Treesearch

Sally M. Haase; Stephen S. Sackett

1998-01-01

Many national parks have incorporated the use of management-ignited prescribed fire in their management plans. Soil and cambium heating, forest floor fuel reduction, and soil nutrient increases have been measured on eight independent, planned management fires over a 9-year period in Sequoia and Kings Canyon National Parks. Findings show that instantaneous lethal...

Post-Fire soil water repellency, hydrologic response, and sediment yield compared between grass-converted and chaparral watersheds

Treesearch

Ken R. Hubbert; Pete M. Wohlgemuth; Jan L. Beyers; Marcia G. Narog; Ross Gerrard

2012-01-01

In 2002, the Williams Fire burned >90 % of the San Dimas Experimental Forest, providing an opportunity to investigate differences in soil water repellency, peak discharge, and sediment yield between grass-converted and chaparral watersheds. Post-fire water repellency and moisture content were measured in the winter and summer for four years. Peak discharge was...

IMPACTS OF LAND USE CHANGE AND FIRE ON NUTRIENT AND CARBON CYCLES AND TRACE GAS EXCHANGE IN SOILS OF THE CERRADO IN CENTRAL BRAZIL

EPA Science Inventory

The Brazilian cerrado is experiencing rapid land use changes that are often accompanied by fire. Here we report initial studies of the effects of fire and land use change on the composition and persistence of litter and soil organic carbon and nitrogen and related changes in the ...

INTERACTIONS OF NUTRIENT AND CARBON CYCLES AND TRACE GAS EXCHANGE WITH LAND USE CHANGE AND FIRE IN THE CERRADO OF CENTRAL BRAZIL

EPA Science Inventory

Land use changes accompanied by fire frequently occur in the Brazilian cerrado. Here we report measurements in the cerrado of the effects of fire and land use change on the composition and persistence of litter and soil organic carbon and nitrogen and related changes in the soil-...

Soil organic matter decomposition and temperature sensitivity after forest fire in permafrost regions in Canada

NASA Astrophysics Data System (ADS)

Aaltonen, Heidi; Palviainen, Marjo; Köster, Kajar; Berninger, Frank; Pumpanen, Jukka

2017-04-01

On the Northern Hemisphere, 24% of soils are underlain by permafrost. These soils contain 50% of the global soil carbon pool. The Northern Hemisphere is also the region which is predicted to be most affected by climate warming and this causes uncertainties over the future of the permafrost. It has been estimated that 25% of permafrost might thaw by 2100, exposing previously frozen carbon pools to decomposition. In addition, global warming is expected to cause increase in the frequency of wild fires, which further increase permafrost melting by removing the insulating organic surface layer. The amount of released soil carbon from permafrost soils after forest fire is affected by degradability and temperature sensitivity of the soil organic matter, as well as soil depth and the stage of succession. Yet the common effect of these factors remains unclear. We studied how soil respiration and its temperature sensitivity (Q10) vary in different depths and within time by taking soil samples from different fire chronosequence areas (burned 3, 25, 46 and 100 years ago) from permafrost region in Northern Canada (Yukon and Northwest Territories, along Dempster Highway). The samples from three different depths (5, 10 and 30 cm) were incubated in four different temperatures (1, 7, 13 and 19°C) over 24h. Our results showed that the CO2 fluxes followed the stages of succession, with recently burned sites having lowest rates. The organic matter at 5 cm depth proved to be more labile and temperature sensitive than in deeper depths. The Q10 values, however, did not differ between sites, excluding 30 cm at the most recently burned site that had a significantly higher Q10 value than the other sites. The results implicate that heterotrophic soil respiration decreases on permafrost regions during the first stages after forest fire. At the same time the temperature sensitivity in deeper soil layers may increase.

Comparison of post-fire seedling establishment between scrub communities in mediterranean and non-mediterranean climate ecosystems

USGS Publications Warehouse

Carrington, M.E.; Keeley, J.E.

1999-01-01

I Both fire regimes and the conditions under which fires occur vary widely. Abiotic conditions (such as climate) in combination with fire season, frequency and intensity could influence vegetation responses to fire. A variety of adaptations facilitate post-fire recruitment in mediterranean climate ecosystems, but responses of other communities are less well known. We evaluated the importance of climate by comparing sites with mediterranean and subtropical climates. 2 We used paired burned and mature sites in chamise chaparral, mixed chaparral and coastal sage scrub (California), and rosemary scrub, sand pine scrub and sand-hill (Florida), to test whether (i) patterns of pre-fire and post-fire seedling recruitment are more similar between communities within a region than between regions, and (ii) post-fire stimulation of seedling establishment is greater in regions with marked fire-induced contrasts in abiotic site characteristics. 3 Post-fire seedling densities were more similar among sites within climatic regions than between regions. Both seedling densities and proportions of species represented by seedlings after fires were generally higher in California. 4 The only site characteristic showing a pre-fire-post-fire contrast was percentage open canopy, and the effect was greater in California than in Florida. Soil properties were unaffected by fire. 5 Mediterranean climate ecosystems in other regions have nutrient-poor soils similar to our subtropical Florida sites, but show post-fire seedling recruitment patterns more similar to the nutrient-rich sites in California. Climate therefore appears to play a more major role than soil characteristics.

Post-wildfire soil erosion in the Mediterranean: Review and future research directions

NASA Astrophysics Data System (ADS)

Shakesby, R. A.

2011-04-01

Wildfires increased dramatically in frequency and extent in the European Mediterranean region from the 1960s, aided by a general warming and drying trend, but driven primarily by socio-economic changes, including rural depopulation, land abandonment and afforestation with flammable species. Published research into post-wildfire hydrology and soil erosion, beginning during the 1980s in Spain, has been followed by studies in other European Mediterranean countries together with Israel and has now attained a sufficiently large critical mass to warrant a major review. Although variations in climate, vegetation, soil, topography and fire severity cause differences in Mediterranean post-wildfire erosion, the long history of human landscape impact up to the present day is responsible for some its distinctive characteristics. This paper highlights these characteristics in reviewing wildfire impacts on hydrology, soil properties and soil erosion by water. The 'mosaic' nature of many Mediterranean landscapes (e.g. an intricate land-use pattern, abandoned terraces and tracks interrupting slopes) may explain sometimes conflicting post-fire hydrological and erosional responses at different sites and spatial scales. First-year post-wildfire soil losses at point- (average, 45-56 t ha - 1 ) and plot-scales (many < 1 t ha - 1 and the majority < 10 t ha - 1 in the first year) are similar to or even lower than those reported for fire-affected land elsewhere or other disturbed (e.g. cultivated) and natural poorly-vegetated (e.g. badlands, rangeland) land in the Mediterranean. The few published losses at larger-scales (hillslope and catchment) are variable. Thin soil and high stone content can explain supply-limited erosion preceding significant protection by recovering vegetation. Peak erosion can sometimes be delayed for years, largely through slow vegetation recovery and temporal variability of erosive storms. Preferential removal of organic matter and nutrients in the commonly thin, degraded soils is arguably just as if not more important than the total soil loss. Aspect is important, with more erosion reported for south- than north-facing slopes, which is attributed to greater fire frequency, slower vegetation recovery on the former and with soil characteristics more prone to erosion (e.g. lower aggregate stability). Post-fire wind erosion is a potentially important but largely neglected process. Gauging the degradational significance of wildfires has relied on comparison with unburnt land, but the focus for comparison should be switched to other agents of soil disturbance and/or currently poorly understood soil renewal rates. Human impact on land use and vegetation may alter expected effects (increased fire activity and post-wildfire erosion) arising from future climatic change. Different future wildfire mitigation responses and likely erosional consequences are outlined. Research gaps are identified, and more research effort is suggested to: (1) improve assessment of post-wildfire erosion impact on soil fertility, through further quantification of soil nutrient depletion resulting from single and multiple fire cycles, and on soil longevity; (2) investigate prescribed fire impacts on carbon release, air pollution and nutrient losses as well as on soil loss; (3) isolate hillslope- and catchment-scale impacts of soil water repellency under Mediterranean post-wildfire conditions; (4) test and refine application of cosmogenic radionuclides to post-wildfire hillslope-scale soil redistribution at different temporal scales; (5) use better temporal resolution of sedimentary sequences to understand palaeofire-erosion-sedimentation links; (6) quantify post-wildfire wind erosion; (7) improve the integration of wildfire into an overall assessment of the processes and impacts of land degradation in the Mediterranean; and (8) raise public awareness of wildfire impact on soil degradation.

Strategies for preventing invasive plant outbreaks after prescribed fire in ponderosa pine forest

USGS Publications Warehouse

Symstad, Amy J.; Newton, Wesley E.; Swanson, Daniel J.

2014-01-01

Land managers use prescribed fire to return a vital process to fire-adapted ecosystems, restore forest structure from a state altered by long-term fire suppression, and reduce wildfire intensity. However, fire often produces favorable conditions for invasive plant species, particularly if it is intense enough to reveal bare mineral soil and open previously closed canopies. Understanding the environmental or fire characteristics that explain post-fire invasive plant abundance would aid managers in efficiently finding and quickly responding to fire-caused infestations. To that end, we used an information-theoretic model-selection approach to assess the relative importance of abiotic environmental characteristics (topoedaphic position, distance from roads), pre-and post-fire biotic environmental characteristics (forest structure, understory vegetation, fuel load), and prescribed fire severity (measured in four different ways) in explaining invasive plant cover in ponderosa pine forest in South Dakota’s Black Hills. Environmental characteristics (distance from roads and post-fire forest structure) alone provided the most explanation of variation (26%) in post-fire cover of Verbascum thapsus (common mullein), but a combination of surface fire severity and environmental characteristics (pre-fire forest structure and distance from roads) explained 36–39% of the variation in post-fire cover of Cirsium arvense (Canada thistle) and all invasives together. For four species and all invasives together, their pre-fire cover explained more variation (26–82%) in post-fire cover than environmental and fire characteristics did, suggesting one strategy for reducing post-fire invasive outbreaks may be to find and control invasives before the fire. Finding them may be difficult, however, since pre-fire environmental characteristics explained only 20% of variation in pre-fire total invasive cover, and less for individual species. Thus, moderating fire intensity or targeting areas of high severity for post-fire invasive control may be the most efficient means for reducing the chances of post-fire invasive plant outbreaks when conducting prescribed fires in this region.

Simulated Rainfall experiments on burned areas

NASA Astrophysics Data System (ADS)

Rulli, Maria Cristina

2010-05-01

Simulated Rainfall experiments were carried out in a Mediterranean area located in Italy, immediately after a forest fire occurrence, to evaluate the effects of forest fire on soil hydraulic properties, runoff and erosion. The selected study area was frequently affected by fire in the last years. Two adjacent 30 mq plots were set up with common physiographic features, and the same fire history, except for the last fire, which burned only one of them. Since both plots were previously subject to the passage of fire 6 years before the last one, one compares the hydrologic response and erosion of an area recently burned (B00) with that of an area burnt 6 years before (B06). Several rainfall simulations were carried out considering different pre-event soil moisture conditions where each rainfall simulation consisted of a single 60 minute application of rainfall with constant intensity of about 76 mm/h. The results show runoff ratio, evaluated for different pre-event soil moisture conditions, ranging from 0 to 2% for B06 plot, and from 21 to 41% for B00. Runoff ratio for the recently burned plot was 60 times higher than for the plot burned six years before, under wet conditions, and 20 times higher, under very wet conditions. A large increase in sediment production also was measured in B00 plot, as compared with that in B06 plot. Suspended sediment yield from B00 plot was more than two orders of magnitude higher than that from B06 plot in all the simulated events. The high runoff and soil losses measured immediately after burning indicate that effective post-fire rehabilitation programs must be carried out to reduce flood risk and soil erosion in recently burned areas. However, the results for the plot burned six year prior show that recovery of the hydrological properties of the soil occurs after the transient post fire modification.

Fire and fire-suppression impacts on forest-soil carbon [Chapter 13

Treesearch

Deborah Page-Dumroese; Martin F. Jurgensen; Alan E. Harvey

2003-01-01

The potential of forest soils to sequester carbon (C) depends on many biotic and abiotic variables, such as: forest type, stand age and structure, root activity and turnover, temperature and moisture conditions, and soil physical, chemical, and biological properties (Birdsey and Lewis, Chapter 2; Johnson and Kern, Chapter 4; Pregitzer, Chapter 6; Morris and Paul,...

Field guide for mapping post-fire soil burn severity

Treesearch

Annette Parson; Peter R. Robichaud; Sarah A. Lewis; Carolyn Napper; Jess T. Clark

2010-01-01

Following wildfires in the United States, the U.S. Department of Agriculture and U.S. Department of the Interior mobilize Burned Area Emergency Response (BAER) teams to assess immediate post-fire watershed conditions. BAER teams must determine threats from flooding, soil erosion, and instability. Developing a postfire soil burn severity map is an important first step...

Fate of carbon in Alaskan Landscapes Project: database for soils from eddy covariance tower sites, Delta Junction, AK

USGS Publications Warehouse

King, Stagg; Harden, Jennifer; Manies, Kristen L.; Munster, Jennie; White, L. Douglas

2002-01-01

Soils in Alaska, and in high latitude terrestrial ecosystems in general, contain significant amounts of organic carbon, most of which is believed to have accumulated since the start of the Holocene about 10 ky before present. High latitude soils are estimated to contain 30-40% of terrestrial soil carbon (Melillo et al., 1995; McGuire and Hobbie, 1997), or ~ 300-400 Gt C (Gt = 1015 g), which equals about half of the current atmospheric burden of carbon. Boreal forests in particular are estimated to have more soil carbon than any other terrestrial biome (Post et al., 1982; Chapin and Matthews, 1993). The relations among net primary production, soil carbon storage, recurrent fire disturbance, nutrients, the hydrologic cycle, permafrost and geomorphology are poorly understood in boreal forest. Fire disturbance has been suggested to play a key role in the interactions among the complex biogeochemical processes influencing carbon storage in boreal forest soils (Harden et al., 2000; Zhuang et al., 2002). There has been an observed increase in fire disturbance in North American boreal black spruce (Picea mariana) forests in recent decades (Murphy et al., 1999; Kasichke et al., 2000), concurrent with increases in Alaskan boreal and arctic surface temperatures and warming of permafrost (Osterkamp and Romanofsky, 1999). Understanding the role of fire in long term carbon storage and how recent changes in fire frequency and severity may influence future high latitude soil carbon pools is necessary for those working to understand or mitigate the effects of global climate change.

Rainfall simulations on a fire disturbed mediterranean area

NASA Astrophysics Data System (ADS)

Rulli, Maria Cristina; Bozzi, Silvia; Spada, Matteo; Bocchiola, Daniele; Rosso, Renzo

2006-08-01

SummaryRainfall simulator experiments were carried out in the Liguria region, Italy, immediately after a forest fire in early August, 2003, to evaluate the effects of forest fire on soil hydraulic properties, runoff and erosion. Two adjacent 30 m 2 plots were set up with common physiographic features, and the same fire history, except for the fire of August 2003, which burned only one of them. Since both plots were previously subject to the passage of fire in March 1997, one compares the hydrologic and sedimentologic response of an area burned in year 2003 (B03) with that of an area burnt 6 years before (B97). Each rainfall simulation consisted of a single 60 min application of rainfall with constant intensity of about 76 mm h -1. The results show runoff ratio, evaluated for different pre-event soil moisture conditions, ranging from 0% to 2% for B97 plot, and from 21% to 41% for B03. Runoff ratio for the recently burned plot was 60 times higher than for the plot burned six years before, under wet conditions, and 20 times higher, under very wet conditions. A large increase in sediment production also was measured in B03 plot, as compared with that in B97 plot. Suspended sediment yield from B03 plot was more than two orders of magnitude higher than that from B97 plot in all the simulated events. The high soil losses measured immediately after burning indicate that effective post-fire rehabilitation programs must be carried out to reduce soil erosion in recently burned areas. However, the results for the plot burned six year prior show that recovery of the hydrological properties of the soil occurs after the transient post-fire modification.

The effect of fire on soil organic matter--a review.

PubMed

González-Pérez, José A; González-Vila, Francisco J; Almendros, Gonzalo; Knicker, Heike

2004-08-01

The extent of the soil organic carbon pool doubles that present in the atmosphere and is about two to three times greater than that accumulated in living organisms in all Earth's terrestrial ecosystems. In such a scenario, one of the several ecological and environmental impacts of fires is that biomass burning is a significant source of greenhouse gases responsible for global warming. Nevertheless, the oxidation of biomass is usually incomplete and a range of pyrolysis compounds and particulate organic matter (OM) in aerosols are produced simultaneously to the thermal modification of pre-existing C forms in soil. These changes lead to the evolution of the OM to "pyromorphic humus", composed by rearranged macromolecular substances of weak colloidal properties and an enhanced resistance against chemical and biological degradation. Hence the occurrence of fires in both undisturbed and agricultural ecosystems may produce long-lasting effects on soils' OM composition and dynamics. Due to the large extent of the C pool in soils, small deviations in the different C forms may also have a significant effect in the global C balance and consequently on climate change. This paper reviews the effect of forest fires on the quantity and quality of soils' OM. It is focused mainly on the most stable pool of soil C; i.e., that having a large residence time, composed of free lipids, colloidal fractions, including humic acids (HA) and fulvic acids (FA), and other resilient forms. The main transformations exerted by fire on soil humus include the accumulation of new particulate C forms highly resistant to oxidation and biological degradation including the so-called "black carbon" (BC). Controversial environmental implications of such processes, specifically in the stabilisation of C in soil and their bearing on the global C cycle are discussed.

Effects of Introduced Grasses, Grazing and Fire on Regional Biogeochemistry in Hawaii

NASA Astrophysics Data System (ADS)

Elmore, A. J.; Asner, G. P.

2003-12-01

African grasses introduced for grazing have expanded in geographic extent in mesic tropical systems of Hawaii and other regions of the world. Grassland expansion leads to increases in fire frequency, speeding woodland and forest destruction at greater geographic scales than occurs with grazing alone. At Pu'uwa'awa'a Ranch, Hawaii, restoration of the native woodland habitat has become a critical objective following the introduction and dominance of the African grass species Pennisetum clandestinum and P. setaceum. Grazing and grass-fueled fires have destroyed over 60% of the original forest. To stabilize these communities, managers must balance the combined effects of grazing and fire. Grazing reduces the recruitment success of native tropical trees, but grazing also reduces fire risk by moderating grass fuel conditions and restricting the extent and density of the most flammable grass species. Our study focuses on two questions: (1) What grazing intensity is necessary to change the fire conditions of a region given in situ soil and precipitation conditions? (2) Have long-term grazing conditions altered soil carbon and nitrogen stocks? We used high resolution imaging spectrometer data to measure photosynthetic and non-photosynthetic vegetation cover, analysis of soil carbon and nitrogen stocks, and measurements of plant community composition along gradients in grazing intensity. P. setaceum, the more flammable alien grass, was dominant where grazing intensity was low and at lower elevations where precipitation is low. The less flammable grass, P. clandestinum, occurred in regions of high grazing intensity and higher precipitation. Grazing influenced the dominance of P. setaceum and P. clandestinum only where precipitation and soil characteristics were suitable for both grasses to occur. At suitable sites, grazing reduced fire conditions through a species sift towards P. clandestinum. Soil carbon and nitrogen stocks decreased with grazing intensity, which was correlated with the fractional cover of P. setaceum. Soil carbon also increased with precipitation. These results show how grazing impacts fire conditions and soil chemistry through changes in species composition, and not through removal of carbon inputs (direct removal of biomass).

Fire increases carbon fluxes from inland waters of the Yukon-Kuskokwim delta, Alaska.

NASA Astrophysics Data System (ADS)

Mann, P. J.; Bristol, E. M.; Dabrowski, J. S.; Jimmie, J. A.; Melton, S.; Navarro-Perez, E.; Peter, D. L.; Sae-lim, N.; Holmes, R. M.; Natali, S.; Schade, J. D.

2017-12-01

Climate change across high-latitude regions is expected to alter the hydrology and biogeochemistry of arctic environments, significantly impacting ecosystem C cycling and landscape scale C budgets. Fire represents one manifestation of arctic climate change with the number, extent and intensity of fires projected to increase over upcoming decades. The Yukon-Kuskokwim River Delta (YKD), Alaska, experienced unprecedented tundra fires in 2015 when more than 250 km2 underwent burn. In this study, we examined the effects of the 2015 YKD fire upon aquatic and terrestrial C fluxes, and investigated potential mechanisms causing changes to C-cycling. Field work was conducted during summer months (July-Sept) over two years, complimented with aerobic and anaerobic laboratory incubations. Burning of the terrestrial organic layer caused dramatic changes to soil moisture, the proportion of organic versus mineral soils near the land surface, and average active layer depth. Fire caused increased C fluxes (particularly CH4) from re-wet soils relative to unburnt soils, suggesting an interaction exists between fire history and soil moisture. Higher C fluxes from saturated ponds and fens across the landscape provided additional support for this theory. Pore-water chemistry in burnt catchments contained higher inorganic nutrient concentrations, specifically nitrogen, potentially driven by changing soil sorption processes and/ or infiltration rates. Organic matter delivery to inland waters within burns contained DOC of lower apparent molecular weight and aromaticity relative to unburnt waters (inferred from optical measures), and waters typically had higher temperatures, pH and dissolved mineral content. Lake and low-lying pond CO2 and CH4 emissions were consistently higher in burn catchment regions, with three to four-fold higher C emission rates. Our study indicates that fire may promote aquatic and terrestrial pathways for C loss and that these enhanced emissions may persist for years following disturbance. A greater understanding of the divergent responses of soils and inland waters after burn and how these drive changes to CO2 and CH4 production are necessary to predict the impact of climate change on landscape C chemistry and fluxes in the future.

Microbial properties and litter and soil nutrients after two prescribed fires in developing savannas in an upland Missouri Ozark Forest

Treesearch

Felix, Jr. Ponder; Mahasin Tadros; Edward F. Loewenstein

2009-01-01

On some landscapes periodic fire may be necessary to develop and maintain oak-dominated savannas. We studied the effects of two annual prescribed burns to determine their effect on microbial activity and soil and litter nutrients 1 year after the last burn. Surface litter and soil from the upper 0?5 cm soil layer in three developing savannas (oak-hickory, ...

Application of thermal analysis to measure the spatial heterogeneity of organic matter degradation after wildfire: implications for post-fire rehabilitation treatments

NASA Astrophysics Data System (ADS)

Merino, Agustin; Fonturbel, M. Teresa; Vega, Jose A.

2015-04-01

Severe wildfires can cause drastic changes in SOM content and quality with important implications for soil conservation and global C balance. Soil heating usually leads to loss of the most labile SOM compounds (e.g. carbohydrates, lipids and peptides) and to generation of aromatic substances. However, these fire-related damages are not uniform over large areas, because of the spatial heterogeneity of different factors such as fire type and environmental conditions. Rapid diagnosis of soil burn severity is required to enable the design of emergency post-fire rehabilitation treatments. The study was conducted in soils from NW Spain, an Atlantic-climate zone that is particularly prone to wildfires. Intact soil cores (forest floor and uppermost mineral soil layer) were taken from a soil developed under granitic rock and subjected to experimental burning (in a bench positioned at the outlet of a wind tunnel). Soil temperature during fire was monitorised and five visual levels of soil burn severity (SBS) were recorded immediately after fire. Solid-state 13C CP-MAS NMR spectroscopy analyses were performed in an Agilent (Varian) VNMRS-500-WB spectrometer. The samples were analyzed by differential scanning calorimetry and thermogravimetry (TGA/DSC, Mettler-Toledo Intl. Inc.). The analyses were performed with 4 mg of samples placed in open aluminium pans under dry air (flow rate, 50 mL-1) and at a scanning rate of 10 °C min-1. The temperature ranged between 50 and 600 °C. In the organic layer, the temperature reached during fire influenced the formation and characteristics of charred material. These materials showed an increasing degree of carbonization/aromatization in relation to the increase of temperature during burning. Burning also led to compounds of higher thermal recalcitrance (increases in T50 values -the temperature at which 50% of the energy stored in SOM is released-). However, values recorded in some samples were lower than those measured in highly polycondensed aromatic compounds. In the mineral soil, large reductions in SOM content were found in both moderate and high SBS (up to 70 %), whereas important effects on SOM quality were only associated with high SBS. NMR analysis revealed these changes as losses of O-alkyl, alkyl and carboxylic structures and increases of the aromatic structures (up to 50 %). In both organic and mineral soils the DSC analysis revealed decreased combustion heat released up to 375 °C, and increased T50. Relationships between thermal properties and chemical-shift regions in the NMR helped provide a better understanding of SOM quality after wildfire. The results also show that thermal analysis can be used as a rapid tool to assess the different degrees of SOM degradation, in areas where the complex heterogeneity of the fire damage requires different emergency post-fire rehabilitation treatments.

More an Exception Than the Rule: Fire has Little Effect on the Magnetic Properties of Loessic Soils Along the Prairie - Forest Ecotone in the Midwestern United States

NASA Astrophysics Data System (ADS)

Geiss, C. E.

2016-12-01

The analysis of a soil profile in western Iowa suggests that forest fires along the prairie-forest ecotone have little effect on the overall magnetic properties of the soil. The studied soil profile is located at Hitchcock Nature Center near Honey Creek, Iowa (41°25'15"N, -95°51'56"W) and developed in a narrow ravine in the Iowa Loess Hills. The surrounding vegetation consists of hardwoods, while the surrounding ridges are vegetated by oak savanna. The area has been subjected to prescribed fires for almost 20 years and is estimated to have burned approximately every 5 years in pre-European times [Stambaugh et al., 2006]. The profile contains several buried soils interspersed by often rapidly deposited loess. Paleosols consist of strongly developed A-horizons but show only weak magnetic enhancement in terms of magnetic susceptibility or ARM/IRM ratios. In a plot of χARM/χFD vs. χARM/χ, all but one sample plot far from the region that is generally associated with past burning [Oldfield and Crowther, 2007]. As shown earlier for prairie environments, fires in oak savanna do not seem to burn hot enough to cause widespread magnetic mineral transformations. Oldfield, F., and J. Crowther (2007), Establishing fire incidence in temperate soils using magnetic measurements, Paleogeogr. Paleoclim. Paleoecol., 249, 362-369. Stambaugh, M. C., R. P. Guyette, E. R. McMurry, and D. C. Dey (2006), Fire history at the eastern Great Plains margin, Missouri River Loess Hills, Great Plains Research, 16, 149-159.

Recovery of biological soil crust richness and cover 12-16 years after wildfires in Idaho, USA

NASA Astrophysics Data System (ADS)

Root, Heather T.; Brinda, John C.; Dodson, E. Kyle

2017-09-01

Changing fire regimes in western North America may impact biological soil crust (BSC) communities that influence many ecosystem functions, such as soil stability and C and N cycling. However, longer-term effects of wildfire on BSC abundance, species richness, functional groups, and ecosystem functions after wildfire (i.e., BSC resilience) are still poorly understood. We sampled BSC lichen and bryophyte communities at four sites in Idaho, USA, within foothill steppe communities that included wildfires from 12 to 16 years old. We established six plots outside each burn perimeter and compared them with six plots of varying severity within each fire perimeter at each site. BSC cover was most strongly negatively impacted by wildfire at sites that had well-developed BSC communities in adjacent unburned plots. BSC species richness was estimated to be 65 % greater in unburned plots compared with burned plots, and fire effects did not vary among sites. In contrast, there was no evidence that vascular plant functional groups or fire severity (as measured by satellite metrics differenced normalized burn ratio (dNBR) or relativized differenced normalized burn ratio (RdNBR)) significantly affected longer-term BSC responses. Three large-statured BSC functional groups that may be important in controlling wind and water erosion (squamulose lichens, vagrant lichens, and tall turf mosses) exhibited a significant decrease in abundance in burned areas relative to adjacent unburned areas. The decreases in BSC cover and richness along with decreased abundance of several functional groups suggest that wildfire can negatively impact ecosystem function in these semiarid ecosystems for at least 1 to 2 decades. This is a concern given that increased fire frequency is predicted for the region due to exotic grass invasion and climate change.

The effect of the fires on gypseous soil properties: changes of the hydrology and splash resistance.

NASA Astrophysics Data System (ADS)

León, J.; Seeger, M.; Echeverría, M.; Badía, D.; Peters, P.

2012-04-01

Mediterranean ecosystems have been severely affected by fires in the last decades. Due to social and economical changes, wildfires have caused hydrological and geomorphologic changes to be more pronounced, resulting in enhanced soil erosion. Soil heating caused by fires affects soil aggregates stability, water infiltration and may generate hydrophobicity. In order to understand how wildfire affects soil hydrological behavior in general, and splash and runoff processes in particular, of gypsum soils,it is advantageous to use a rainfall simulator. In August 2009 a large forest fire affected 6700 ha in Remolinos (NW Zaragoza, Spain). The area is covered by shrubs such as gorse (Genista scorpius L.), broom (Retama sphaerocarpa L.) and rosemary (Rosmarinus officinalis L.), and with small areas occupied by Aleppo pine (Pinus halepensis Mill) and Kermes evergreen-oak (Quercus coccifera L.). This region has a semarid Mediterranean climate, with an average annual rainfall ca 560 mm and a mean annual temperature of 12.5°C, resulting in an estimated climatic water deficit of ca. 400mm. The relief consists of stepped slopes (200-748 m), on two different types of soil have developed: Renzic Phaeozem, on limestone, and Haplic Gypsisol, on gypsum (IUSS, 2006). Within this study, we wanted to investigate the differences in affection by fire of the different soil types, as it may be caused by different fire intensities. Therefore, both soil types were sampled after fire. Also, similar locations were sampled which were not affected by the wildfires. With this, we could differentiate 4 treatments: burnt and unburnt pine forest and burnt and unburnt shrub on gypseous soils. We designed a set of lab experiments to elucidate the effect of heat on soil composition, aggregate stability, and splash susceptibility. Samples were taken using cylinders of 5 cm depth. Under laboratory conditions were measured pH, CE, organic matter (OM), soil aggregates stability (SAS), bulk density, porosity and mineralogical changes, using 5 subsamples of each treatment. The samples were heated at different temperatures (105 °C and 205 °C) in an oven for 30 min to simulated different fire intensities, for comparison. A set was only air dried (35 °C). To study the splash effect of the gypsum soils were use small scale rainfall simulator in laboratory, applying a rainfall intensity of 47 mm h-1 during 20 min, resulting in a kinetic energy of 8.94 J m-2 mm-1. The gross loss of material of each of the undisturbed samples was measured after 20 minutes of simulation. The pH is slightly alkaline and oscillates between 7.93-8.32, depending on soil cover type, and is highest under burnt pine forest. The EC (2.08-5.01 mS cm-1) did not change after heating of the unburnt shrub cover, but in the soil under burnt pine forest, the EC was lowered with increasing temperature. The OM content is moderate (3.73-4.85 %), and higher on burnt soils, increasing also with an increase of treatment temperature. The SAS (43.17-75.92 %) is strongly depending on the temperature applied, and was found higher on the burnt surfaces. The gypsum content of the soils is moderate to high (11.30-39.58 %), but decreases with the treatment at 205°C. The soil loss by splash vaied between 0.9 to 2.8 g (per sample) after 20 min of rainfall simulation. Highest losses were found on burnt surfaces. The results show that fire and temperature affects not all characteristics of soils. Acknowledgements: This research was supported by the Ministry of Science and Innovation BES-2008-003056, the CETSUS project (CGL2007-66644-C04-04/HIDCLI) and the Geomorphology and Global Change Research Group (D.G.A., 2011). The Spanish Army has supported this work at the San Gregorio CENAF.

[Measurement model of carbon emission from forest fire: a review].

PubMed

Hu, Hai-Qing; Wei, Shu-Jing; Jin, Sen; Sun, Long

2012-05-01

Forest fire is the main disturbance factor for forest ecosystem, and an important pathway of the decrease of vegetation- and soil carbon storage. Large amount of carbonaceous gases in forest fire can release into atmosphere, giving remarkable impacts on the atmospheric carbon balance and global climate change. To scientifically and effectively measure the carbonaceous gases emission from forest fire is of importance in understanding the significance of forest fire in the carbon balance and climate change. This paper reviewed the research progress in the measurement model of carbon emission from forest fire, which covered three critical issues, i. e., measurement methods of forest fire-induced total carbon emission and carbonaceous gases emission, affecting factors and measurement parameters of measurement model, and cause analysis of the uncertainty in the measurement of the carbon emissions. Three path selections to improve the quantitative measurement of the carbon emissions were proposed, i. e., using high resolution remote sensing data and improving algorithm and estimation accuracy of burned area in combining with effective fuel measurement model to improve the accuracy of the estimated fuel load, using high resolution remote sensing images combined with indoor controlled environment experiments, field measurements, and field ground surveys to determine the combustion efficiency, and combining indoor controlled environment experiments with field air sampling to determine the emission factors and emission ratio.

Influence on soil properties of prescribed burning under mature red pine.

Treesearch

1977-01-01

Prescribed fires in mature red pine stands reduced shrub competition and the organic layer thickness. The fires reduced nutrient in the forest floor, increased them in the mineral soil, but had no effect on overstory growth.

Potential health impacts from range fires at Aberdeen Proving Ground, Maryland.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Willians, G.P.; Hermes, A.M.; Policastro, A.J.

1998-03-01

This study uses atmospheric dispersion computer models to evaluate the potential for human health impacts from exposure to contaminants that could be dispersed by fires on the testing ranges at Aberdeen Proving Ground, Maryland. It was designed as a screening study and does not estimate actual human health risks. Considered are five contaminants possibly present in the soil and vegetation from past human activities at APG--lead, arsenic, trichloroethylene (TCE), depleted uranium (DU), and dichlorodiphenyltrichloroethane (DDT); and two chemical warfare agents that could be released from unexploded ordnance rounds heated in a range fire--mustard and phosgene. For comparison, dispersion of twomore » naturally occurring compounds that could be released by burning of uncontaminated vegetation--vinyl acetate and 2-furaldehyde--is also examined. Data from previous studies on soil contamination at APG are used in conjunction with conservative estimates about plant uptake of contaminants, atmospheric conditions, and size and frequency of range fires at APG to estimate dispersion and possible human exposure. The results are compared with US Environmental Protection Agency action levels. The comparisons indicate that for all of the anthropogenic contaminants except arsenic and mustard, exposure levels would be at least an order of magnitude lower than the corresponding action levels. Because of the compoundingly conservative nature of the assumptions made, they conclude that the potential for significant human health risks from range fires is low. The authors recommend that future efforts be directed at fire management and control, rather than at conducting additional studies to more accurately estimate actual human health risk from range fires.« less

The effects of fire on soil hydrologic properties and sediment fluxes in chaparral steeplands, southern California

Treesearch

P. M. Wohlgemuth; K. R. Hubbert

2008-01-01

Fire is a major disturbance event in southwestern ecosystems. A prescribed burn in the San Dimas Experimental Forest provided an opportunity to quantify the effects of fire on soil hydrologic properties and sediment fluxes in chaparral-covered steeplands. Located in the San Gabriel Mountains about 50 km northeast of Los Angeles, a 1.28 ha watershed was instrumented...

Fire effects on the mobilization and uptake of nitrogen by cheatgrass (Bromus tectorum L.)

Treesearch

Brittany G. Johnson; Dale W. Johnson; Jeanne C. Chambers; Robert R. Blank

2011-01-01

Cheatgrass (Bromus tectorum L.), an invasive annual grass, is displacing native species and causing increased fire frequency in the Great Basin of the southwestern United States. Growth and nitrogen uptake patterns by cheatgrass were examined in a greenhouse study using soils from sites with the same soil type but different fire histories: 1) an area that burned in...

Rapid-response tools and datasets for post-fire remediation: Linking remote sensing and process-based hydrological models

Treesearch

M. E. Miller; William Elliot; M. Billmire; Pete Robichaud; K. A. Endsley

2016-01-01

Post-wildfire flooding and erosion can threaten lives, property and natural resources. Increased peak flows and sediment delivery due to the loss of surface vegetation cover and fire-induced changes in soil properties are of great concern to public safety. Burn severity maps derived from remote sensing data reflect fire-induced changes in vegetative cover and soil...

Forest fuels on organic and associated soils in the Coastal Plain of North Carolina

Treesearch

G. W. Wendel; T. G Storey; G. M. Byram

1962-01-01

The fire problem in the organic soil (pocosin) areas of eastern North Carolina centers a round the frequent and costly blowup wildfires occurring there and the use of fire as a management tool. Under certain combinations of fuel and weather, low intensity fires will suddenly and often unexpectedly multiply their rate of energy output many times . In almost all...

"Fire Moss" Cover and Function in Severely Burned Forests of the Western United States

NASA Astrophysics Data System (ADS)

Grover, H.; Doherty, K.; Sieg, C.; Robichaud, P. R.; Fulé, P. Z.; Bowker, M.

2017-12-01

With wildfires increasing in severity and extent throughout the Western United States, land managers need new tools to stabilize recently burned ecosystems. "Fire moss" consists of three species, Ceratodon purpureus, Funaria hygrometrica, and Bryum argentum. These mosses colonize burned landscapes quickly, aggregate soils, have extremely high water holding capacity, and can be grown rapidly ex-situ. In this talk, I will focus on our efforts to understand how Fire Moss naturally interacts with severely burned landscapes. We examined 14 fires in Arizona, New Mexico, Washington, and Idaho selecting a range of times since fire, and stratified plots within each wildfire by winter insolation and elevation. At 75+ plots we measured understory plant cover, ground cover, Fire Moss cover, and Fire Moss reproductive effort. On plots in the Southwest, we measured a suite of soil characteristics on moss covered and adjacent bare soil including aggregate stability, shear strength, compressional strength, and infiltration rates. Moss cover ranged from 0-75% with a mean of 16% across all plots and was inversely related to insolation (R2 = .32, p = <.01), directly related to elevation (R2 = .13, p = .02), and not related to slope (R2 = .02, p =.41). Moss covered areas had twice as much shear strength and compressional strength, and three times higher aggregate stability and infiltration rates as adjacent bare ground. These results will allow us to model locations where Fire Moss will naturally increase postfire hillslope soil stability, locations for targeting moss restoration efforts, and suggest that Fire Moss could be a valuable tool to mitigate post wildfire erosion.

Ecohydrologic Implications and Management of Post-fire Soil Water Repellency in Burned Pinon-Juniper Woodlands

NASA Astrophysics Data System (ADS)

Madsen, Matthew; Zvirzdin, Daniel; Fernelius, Kaitlynn; McMillan, Mica; Kostka, Stanley

2014-05-01

Erosion and weed dominance often limit the recovery of piñon-juniper woodlands of western North America after high intensity wildfires. Soil water repellency (SWR) is one factor that may promote overland flow and impede seedling establishment. In spite of these effects, the influence of post-fire SWR on site recovery is poorly understood. Our presentation summarizes data collected within studies on burned piñon-juniper woodlands that provide new insight on: 1) the spatial distribution and severity of SWR, 2) influence of SWR on soil hydrology, nitrogen cycling, and site revegetation, and 3) the suitability of soil surfactants as a post-fire restoration tool. We demonstrate how patterns of SWR are highly correlated to pre-fire woodland canopy structure. At sites where SWR is present, infiltration, soil water content, and plant establishment is significantly less than at non-hydrophobic sites. We show how newly developed soil surfactants can significantly improve ecohydrologic properties required for plant growth by overcoming SWR; thus, increasing the amount and duration of available water for seed germination and plant growth. However, the application of soil surfactants in wildfire-affected ecosystems has been limited due to logistical and economic constraints associated with the standard practice of using large quantities of irrigation water as the surfactant carrier. We have developed a potential solution to this problem by using seed coating technology to use the seed as the carrier for the delivery of soil surfactant. Through this approach, precipitation leaches the surfactant from the seed into the soil where it absorbs onto the soil particles and ameliorates water repellency within the seeds microsite. We present findings from laboratory and field evaluations of surfactant seed coatings, which provide evidence that it may be plausible for the technology to improve post-fire seeding efforts by restoring soil hydrologic function and increasing seedling emergence and early seedling development.

Fate of the chemical warfare agent O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX) on soil following accelerant-based fire and liquid decontamination.

PubMed

Gravett, M R; Hopkins, F B; Self, A J; Webb, A J; Timperley, C M; Riches, J R

2014-08-01

In the event of alleged use of organophosphorus nerve agents, all kinds of environmental samples can be received for analysis. These might include decontaminated and charred matter collected from the site of a suspected chemical attack. In other scenarios, such matter might be sampled to confirm the site of a chemical weapon test or clandestine laboratory decontaminated and burned to prevent discovery. To provide an analytical capability for these contingencies, we present a preliminary investigation of the effect of accelerant-based fire and liquid decontamination on soil contaminated with the nerve agent O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX). The objectives were (a) to determine if VX or its degradation products were detectable in soil after an accelerant-based fire promoted by aviation fuel, including following decontamination with Decontamination Solution 2 (DS2) or aqueous sodium hypochlorite, (b) to develop analytical methods to support forensic analysis of accelerant-soaked, decontaminated and charred soil and (c) to inform the design of future experiments of this type to improve analytical fidelity. Our results show for the first time that modern analytical techniques can be used to identify residual VX and its degradation products in contaminated soil after an accelerant-based fire and after chemical decontamination and then fire. Comparison of the gas chromatography-mass spectrometry (GC-MS) profiles of VX and its impurities/degradation products from contaminated burnt soil, and burnt soil spiked with VX, indicated that the fire resulted in the production of diethyl methylphosphonate and O,S-diethyl methylphosphonothiolate (by an unknown mechanism). Other products identified were indicative of chemical decontamination, and some of these provided evidence of the decontaminant used, for example, ethyl 2-methoxyethyl methylphosphonate and bis(2-methoxyethyl) methylphosphonate following decontamination with DS2. Sample preparation procedures and analytical methods suitable for investigating accelerant and decontaminant-soaked soil samples are presented. VX and its degradation products and/or impurities were detected under all the conditions studied, demonstrating that accelerant-based fire and liquid-based decontamination and then fire are unlikely to prevent the retrieval of evidence of chemical warfare agent (CWA) testing. This is the first published study of the effects of an accelerant-based fire on a CWA in environmental samples. The results will inform defence and security-based organisations worldwide and support the verification activities of the Organisation for the Prohibition of Chemical Weapons (OPCW), winner of the 2013 Nobel Peace Prize for its extensive efforts to eliminate chemical weapons.

Using small-scale rainfall simulation to assess temporal changes in pre- and post-fire soil hydrology and erosion: the value of fixed-position plots

NASA Astrophysics Data System (ADS)

Ferreira, Carla S. S.; Shakesby, Rick A.; Bento, Célia P. M.; Walsh, Rory P. D.; Ferreira, António J. D.

2013-04-01

In recent decades, wildfire has become both frequent and severe in southern Europe leading to widespread research into its impacts on soil erosion, soil and water quality. Rainfall simulation has become established as a popular technique to assess these impacts, as it can be conducted under controlled conditions (notably, with respect to rainfall) and is a very cost-effective and rapid way to compare overland flow and suspended sediment generation within burned and unburned sites. Particular advantages are that: (1) results can be obtained before the first post-fire rainfall events; and (2) experiments can reproduce controlled storm events, with similar characteristics to natural rain. Although plot sizes vary (0.09-30m2), most researchers have used < 1m2 plots because of logistical difficulties of setting up larger plots especially in burned areas that may lack good access and local water supplies. Disadvantages with using small plots, however, particularly on burned terrain, include: (1) the difficulty of installing the plots without disturbing the soil; (2) the strong influence of plot boundaries on overland flow and sediment production. Significant replication is generally considered necessary to take account of high variability in results that are due in part to these effects. One response to these problems is a 'fixed plot' approach in which bounded plots are left in place for re-use throughout the study. A problem here, however, would be progressive sediment exhaustion due to the 'island' effect of the plots caused by their isolation from upslope sediment transfer. This paper assesses the usefulness of a repeat-simulation plot approach in assessing temporal change in overland flow and erosion in post-fire situations that minimizes the island effect by partial removal of plot boundaries between surveys. This approach was tested over a 2.5-year period in a small (9 ha) catchment in central Portugal subjected to an experimental fire in 2009. Five rainfall simulation plots 0.25m2 in size were installed close to sediment traps (contributing areas: 498-4238m2) collecting sediment eroded by overland flow caused by natural rainfall. The plots were installed pre-fire and experiments carried out under 'dry' and 'wet' antecedent conditions on six occasions from pre-fire to two years after the fire. The lateral boundaries of each plot were left in place, but the upslope boundary and central (outlet) section of the downslope boundary were removed between surveys and re-installed and sealed each time measurements were carried out. Having fixed positions of plots minimised soil disturbance on each monitoring occasion and meant that, for any given plot, results were directly comparable and gave a more reliable picture of change through time. Removing the upper and lower boundaries of the plots between measurements allowed the soil to undergo processes similar to those on the surrounding slope and reduced the 'island' effect associated with continuously bounded plots. Results from the adjacent sediment traps, which provided a parallel temporal record of hillslope-scale overland flow and sediment redistribution patterns under natural rainfall, are used to judge the usefulness of the in situ simulation plots approach.

Using hyperspectral imagery to predict post-wildfire soil water repellency

Treesearch

Sarah A. Lewis; Peter R. Robichaud; Bruce E. Frazier; Joan Q. Wu; Denise Y. M. Laes

2008-01-01

A principal task of evaluating large wildfires is to assess fire's effect on the soil in order to predict the potential watershed response. Two types of soil water repellency tests, the water drop penetration time (WDPT) test and the mini-disk infiltrometer (MDI) test, were performed after the Hayman Fire in Colorado, in the summer of 2002 to assess the...

Carbon loss from an unprecedented Arctic tundra wildfire

Treesearch

Michelle C. Mack; M. Syndonia Bret-Harte; Teresa N. Hollingsworth; Randi R. Jandt; Edward A.G. Schuur; Gaius R. Shaver; David L. Verbyla

2011-01-01

Arctic tundra soils store large amounts of carbon (C) in organic soil layers hundreds to thousands of years old that insulate, and in some cases maintain, permafrost soils. Fire has been largely absent from most of this biome since the early Holocene epoch, but its frequency and extent are increasing, probably in response to climate warming. The effect of fires on the...

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

Treesearch

M.A. Callaham; J.M. Blair; T.C. Todd; D.J. Kitchen; M.R. Whiles

2003-01-01

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups. and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station. we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term...

Response of two semiarid grasslands to a second fire application

Treesearch

Carleton S. White; Rosemary L. Pendleton; Burton K. Pendleton

2006-01-01

Prescribed fire was used in two semiarid grasslands to reduce shrub cover, promote grass production, and reduce erosional loss that represents a potential non­point-source of sediment to degrade water quality. This study measured transported soil sediment, dynamics in soil surface microtopography, cover of the woody shrub, grass, and bare ground cover classes, and soil...

Temporal evolution of water repellency and preferential flow in the post-fire

NASA Astrophysics Data System (ADS)

Alanís, Nancy; Jordán, Antonio; Zavala, Lorena M.

2015-04-01

Forest fires usually intensify erosive process due to the reduction of vegetation cover and degradation of aggregation in the topsoil. Another common effect of wildifres is the development of soil water repellency, which in turn favors the formation of runoff, inhibiting or delaying infiltration. Under these conditions, infiltration occurs only when ponded water or runoff flow finds macropores and cracks in the soil surface, producing preferential flow pathways. When water infiltrates through these paths, a significant portion of the soil remains dry, limiting the supply of nutrients to the roots, favoring the rapid leaching of nutrients and agrochemicals, and other impacts on flora and hydrological processes at hillslope- or basin-scale. The existence of irregular wetting fronts has been observed frequently in burned or unburned water repellent soils. Although some authors have suggested that preferential flow paths may be more or less permanent in the case of unburned soils, the temporal evolution of preferential flow has been rarely studied in burned soils during the post-fire, after water repellency decreases or disappears. This research focuses on the temporal evolution of water repellency and preferential flows in an area affected by fire.

Long term repeated fire disturbance alters soil bacterial diversity but not the abundance in an Australian wet sclerophyll forest.

PubMed

Shen, Ju-pei; Chen, C R; Lewis, Tom

2016-01-20

Effects of fire on biogeochemical cycling in terrestrial ecosystem are widely acknowledged, while few studies have focused on the bacterial community under the disturbance of long-term frequent prescribed fire. In this study, three treatments (burning every two years (B2), burning every four years (B4) and no burning (B0)) were applied for 38 years in an Australian wet sclerophyll forest. Results showed that bacterial alpha diversity (i.e. bacterial OTU) in the top soil (0-10 cm) was significantly higher in the B2 treatment compared with the B0 and B4 treatments. Non-metric multidimensional analysis (NMDS) of bacterial community showed clear separation of the soil bacterial community structure among different fire frequency regimes and between the depths. Different frequency fire did not have a substantial effect on bacterial composition at phylum level or bacterial 16S rRNA gene abundance. Soil pH and C:N ratio were the major drivers for bacterial community structure in the most frequent fire treatment (B2), while other factors (EC, DOC, DON, MBC, NH4(+), TC and TN) were significant in the less frequent burning and no burning treatments (B4 and B0). This study suggested that burning had a dramatic impact on bacterial diversity but not abundance with more frequent fire.

Long term repeated fire disturbance alters soil bacterial diversity but not the abundance in an Australian wet sclerophyll forest

PubMed Central

Shen, Ju-pei; Chen, C. R.; Lewis, Tom

2016-01-01

Effects of fire on biogeochemical cycling in terrestrial ecosystem are widely acknowledged, while few studies have focused on the bacterial community under the disturbance of long-term frequent prescribed fire. In this study, three treatments (burning every two years (B2), burning every four years (B4) and no burning (B0)) were applied for 38 years in an Australian wet sclerophyll forest. Results showed that bacterial alpha diversity (i.e. bacterial OTU) in the top soil (0–10 cm) was significantly higher in the B2 treatment compared with the B0 and B4 treatments. Non-metric multidimensional analysis (NMDS) of bacterial community showed clear separation of the soil bacterial community structure among different fire frequency regimes and between the depths. Different frequency fire did not have a substantial effect on bacterial composition at phylum level or bacterial 16S rRNA gene abundance. Soil pH and C:N ratio were the major drivers for bacterial community structure in the most frequent fire treatment (B2), while other factors (EC, DOC, DON, MBC, NH4+, TC and TN) were significant in the less frequent burning and no burning treatments (B4 and B0). This study suggested that burning had a dramatic impact on bacterial diversity but not abundance with more frequent fire. PMID:26787458

Long-term dynamics of soil chemical properties after a prescribed fire in a Mediterranean forest (Montgrí Massif, Catalonia, Spain).

PubMed

Alcañiz, M; Outeiro, L; Francos, M; Farguell, J; Úbeda, X

2016-12-01

This study examines the effects of a prescribed fire on soil chemical properties in the Montgrí Massif (Girona, Spain). The prescribed forest fire was conducted in 2006 to reduce understory vegetation and so prevent potential severe wildfires. Soil was sampled at a depth of 0-5cm at 42 sampling points on four separate occasions: prior to the event, immediately after, one year after and nine years after. The parameters studied were pH, electrical conductivity (EC), total carbon (C), total nitrogen (N), available phosphorus (P), potassium (K + ), calcium (Ca 2+ ) and magnesium (Mg 2+ ). All parameters (except pH) increased significantly immediately after the fire. One year after burning, some chemical parameters - namely, EC, available P and K + - had returned to their initial, or even lower, values; while others - pH and total C - continued to rise. Total N, Ca 2+ and Mg 2+ levels had fallen one year after the fire, but levels were still higher than those prior to the event. Nine years after the fire, pH, total C, total N and available P are significantly lower than pre-fire values and nutrients concentrations are now higher than at the outset but without statistical significance. The soil system, therefore, is still far from being recovered nine years later. Copyright © 2016 Elsevier B.V. All rights reserved.

Wildland fire ash: Production, composition and eco-hydro-geomorphic effects

USGS Publications Warehouse

Bodi, Merche B.; Martin, Deborah; Balfour, Victoria N.; Santin, Cristina; Doerr, Stefan H.; Pereira, Paulo; Cerda, Artemi; Mataix-Solera, Jorge

2014-01-01

Fire transforms fuels (i.e. biomass, necromass, soil organic matter) into materials with different chemical and physical properties. One of these materials is ash, which is the particulate residue remaining or deposited on the ground that consists of mineral materials and charred organic components. The quantity and characteristics of ash produced during a wildland fire depend mainly on (1) the total burned fuel (i.e. fuel load), (2) fuel type and (3) its combustion completeness. For a given fuel load and type, a higher combustion completeness will reduce the ash organic carbon content, increasing the relative mineral content, and hence reducing total mass of ash produced. The homogeneity and thickness of the ash layer can vary substantially in space and time and reported average thicknesses range from close to 0 to 50 mm. Ash is a highly mobile material that, after its deposition, may be incorporated into the soil profile, redistributed or removed from a burned site within days or weeks by wind and water erosion to surface depressions, footslopes, streams, lakes, reservoirs and, potentially, into marine deposits.Research on the composition, properties and effects of ash on the burned ecosystem has been conducted on material collected in the field after wildland and prescribed fires as well as on material produced in the laboratory. At low combustion completeness (typically T < 450 °C), ash is organic-rich, with organic carbon as the main component. At high combustion completeness (T > 450 °C), most organic carbon is volatized and the remaining mineral ash has elevated pH when in solution. It is composed mainly of calcium, magnesium, sodium, potassium, silicon and phosphorous in the form of inorganic carbonates, whereas at T > 580 °C the most common forms are oxides. Ash produced under lower combustion completeness is usually darker, coarser, and less dense and has a higher saturated hydraulic conductivity than ash with higher combustion completeness, although physical reactions with CO2 and when moistened produce further changes in ash characteristics.As a new material present after a wildland fire, ash can have profound effects on ecosystems. It affects biogeochemical cycles, including the C cycle, not only within the burned area, but also globally. Ash incorporated into the soil increases temporarily soil pH and nutrient pools and changes physical properties such as albedo, soil texture and hydraulic properties including water repellency. Ash modifies soil hydrologic behavior by creating a two-layer system: the soil and the ash layer, which can function in different ways depending on (1) ash depth and type, (2) soil type and (3) rainfall characteristics. Key parameters are the ash's water holding capacity, hydraulic conductivity and its potential to clog soil pores. Runoff from burned areas carries soluble nutrients contained in ash, which can lead to problems for potable water supplies. Ash deposition also stimulates soil microbial activity and vegetation growth.Further work is needed to (1) standardize methods for investigating ash and its effects on the ecosystem, (2) characterize ash properties for specific ecosystems and wildland fire types, (3) determine the effects of ash on human and ecosystem health, especially when transported by wind or water, (4) investigate ash's controls on water and soil losses at slope and catchment scales, (5) examine its role in the C cycle, and (6) study its redistribution and fate in the environment.

Speciation and phytoavailability of lead and antimony in a small arms range soil amended with mussel shell, cow bone and biochar: EXAFS spectroscopy and chemical extractions.

PubMed

Ahmad, Mahtab; Lee, Sang Soo; Lim, Jung Eun; Lee, Sung-Eun; Cho, Ju Sik; Moon, Deok Hyun; Hashimoto, Yohey; Ok, Yong Sik

2014-01-01

Mussel shell (MS), cow bone (CB) and biochar (BC) were selected to immobilize metals in an army firing range soil. Amendments were applied at 5% (wt) and their efficacies were determined after 175 d. For metal phytoavailability test, maize (Zea mays L.) plants were cultivated for 3weeks. Results showed that all amendments decreased the exchangeable Pb by up to 99% in planted/unplanted soils. Contrarily, exchangeable Sb were increased in the MS- and CB-amended soils. The rise in soil pH (~1 unit) by the amendments affected Pb and Sb mobility in soils. Bioavailability of Pb to maize was reduced by up to 71% in the amended soils. The Sb uptake to maize was decreased by up to 53.44% in the BC-amended soil. Sequential chemical extractions showed the transformation of easily available Pb to stable residual form with the amendment treatments. Scanning electron microscopic elemental dot mapping revealed the Pb association with Al and Si in the MS-amended soil and that with P in the CB- and BC-amended soils. Additionally, the extended X-ray absorption fine structure spectroscopic analysis indicated the transformation of organic bound Pb in unamended control soil to relatively more stable Pb-hydroxide (Ksp=10(-17.1)), chloropyromorphite (Ksp=10(-84.4)) and Pb-phosphate (Ksp=10(-23.8)) in soils amended with MS, CB and BC, respectively. Application of BC was the best in decreasing the phytoavailability of Pb and Sb in the studied army firing range soil. Copyright © 2013 Elsevier Ltd. All rights reserved.

Boreal Forests Sequester Large Amounts of Mercury over Millennial Time Scales in the Absence of Wildfire.

PubMed

Giesler, Reiner; Clemmensen, Karina E; Wardle, David A; Klaminder, Jonatan; Bindler, Richard

2017-03-07

Alterations in fire activity due to climate change and fire suppression may have profound effects on the balance between storage and release of carbon (C) and associated volatile elements. Stored soil mercury (Hg) is known to volatilize due to wildfires and this could substantially affect the land-air exchange of Hg; conversely the absence of fires and human disturbance may increase the time period over which Hg is sequestered. Here we show for a wildfire chronosequence spanning over more than 5000 years in boreal forest in northern Sweden that belowground inventories of total Hg are strongly related to soil humus C accumulation (R 2 = 0.94, p < 0.001). Our data clearly show that northern boreal forest soils have a strong sink capacity for Hg, and indicate that the sequestered Hg is bound in soil organic matter pools accumulating over millennia. Our results also suggest that more than half of the Hg stock in the sites with the longest time since fire originates from deposition predating the onset of large-scale anthropogenic emissions. This study emphasizes the importance of boreal forest humus soils for Hg storage and reveals that this pool is likely to persist over millennial time scales in the prolonged absence of fire.

Analytical results from an environmental investigation of six sites on Kirtland Air Force Base, New Mexico, 1993-94

USGS Publications Warehouse

Wilcox, Ralph

1995-01-01

The six sites investigated include silver recovery units; a buried caustic drain line; a neutralization pit; an evaporation/infiltration pond; the Manzano fire training area; and a waste oil underground storage tank. Environmental samples of soil, pond sediment, soil gas, and water and gas in floor drains were collected and analyzed. Field quality-control samples were also collected and analyzed in association with the environmental samples. The six sites were investigated because past or current activities could have resulted in contamination of soil, pond sediment, or water and sediment in drains.