Science.gov

Sample records for forest production responses

  1. Responses of temperate forest productivity to insect and pathogen disturbances

    NASA Astrophysics Data System (ADS)

    Flower, C. E.; Gonzalez-Meler, M. A.

    2014-12-01

    Climate forcing factors have been documented to directly (e.g. CO2 fertilization) or indirectly (e.g. temperature and vapor pressure deficit) affect net primary productivity (NPP) of forests. Climate variations can also affect the vulnerability of forests to pests and pathogens, causing diffuse or widespread mortality. The introduction of novel pests is causing rapid mortality of targeted species with undetermined effects on forest productivity: NPP could decrease or increase depending on the severity (proportion of basal area impacted) and species diversity. We attempted to document the impact of diffuse mortality caused by insect outbreaks on North American temperate forests through synthesis of literature. Despite the large number of studies (>500) only a few (12) documented NPP in a systematic manner. The magnitude of insect and pathogen disturbance was larger in western than eastern forests due to the redundancy and functional diversity of temperate deciduous and mixed deciduous forests. Recovery from disturbance was more rapid from diffuse short duration defoliation events relative to the long lasting impacts of wood boring insects. Forest resilience may decrease as insect disturbance increases, particularly with generalist invasive pests that target a variety of species. We conclude that these biotic interactions, particularly when caused by invasive pests, impose biological forcing to forest NPP at similar magnitude and time scales than climate forcing.

  2. Responses of temperate forest productivity to insect and pathogen disturbances.

    PubMed

    Flower, Charles E; Gonzalez-Meler, Miquel A

    2015-01-01

    Pest and pathogen disturbances are ubiquitous across forest ecosystems, impacting their species composition, structure, and function. Whereas severe abiotic disturbances (e.g., clear-cutting and fire) largely reset successional trajectories, pest and pathogen disturbances cause diffuse mortality, driving forests into nonanalogous system states. Biotic perturbations that disrupt forest carbon dynamics either reduce or enhance net primary production (NPP) and carbon storage, depending on pathogen type. Relative to defoliators, wood borers and invasive pests have the largest negative impact on NPP and the longest recovery time. Forest diversity is an important contributing factor to productivity: NPP is neutral, marginally enhanced, or reduced in high-diversity stands in which a small portion of the canopy is affected (temperate deciduous or mixed forests) but very negative in low-diversity stands in which a large portion of the canopy is affected (western US forests). Pests and pathogens reduce forest structural and functional redundancy, affecting their resilience to future climate change or new outbreaks. Therefore, pests and pathogens can be considered biotic forcing agents capable of causing consequences of similar magnitude to climate forcing factors. PMID:25580836

  3. Contrasting responses of terrestrial ecosystem production to hot temperature extreme regimes between grassland and forest

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Voigt, M.; Liu, H.

    2015-01-01

    During the past several decades, observational data have shown a faster increase in hot temperature extremes than the change in mean temperature. Increasingly high extreme temperatures are expected to affect terrestrial ecosystem function. The ecological impact of hot extremes on vegetation production, however, remains uncertain across biomes in natural climatic conditions. In this study, we investigated the effects of hot temperature extremes on vegetation production by combining the MODIS enhanced vegetation index (EVI) data set and in situ climatic records during the period 2000 to 2009 from 12 long-term experimental sites across biomes and climate. Our results show that higher mean annual maximum temperatures (Tmax) greatly reduced grassland production, and yet enhanced forest production after removing the effect of precipitation. The relative decrease in vegetation production was 16% for arid grassland and 7% for mesic grassland, and the increase was 5% for forest. We also observed a significantly positive relationship between interannual aboveground net primary production (ANPP) and Tmax for the forest biome (R2 = 0.79, P < 0.001). This line of evidence suggests that hot temperature extremes lead to contrasting ecosystem-level responses of vegetation production between grassland and forest biomes. Given that many terrestrial ecosystem models use average daily temperature as input, predictions of ecosystem production should consider such contrasting responses to increasingly hot temperature extreme regimes associated with climate change.

  4. Contrasting responses of terrestrial ecosystem production to hot temperature extreme regimes between grassland and forest

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Voigt, M.; Liu, H.

    2014-04-01

    Observational data during the past several decades show faster increase of hot temperature extremes over land than changes in mean temperature. Towards more extreme temperature is expected to affect terrestrial ecosystem function. However, the ecological impacts of hot extremes on vegetation production remain uncertain across biomes in natural climatic conditions. In this study, we investigated the effects of hot temperature extremes on aboveground net primary production (ANPP) by combining MODIS EVI dataset and in situ climatic records during 2000 to 2009 from 12 long-term experimental sites across biomes and climates. Our results showed that higher mean annual maximum temperatures (Tmax) greatly reduced grassland production, and yet enhanced forest production after removing the effects of precipitation. Relative decreases in ANPP were 16% for arid grassland and 7% for mesic grassland, and the increase were 5% for forest. We also observed a significant positive relationship between interannual ANPP and Tmax for forest biome (R2 = 0.79, P < 0.001). This line of evidence suggests that hot temperature extreme leads to contrasting ecosystem-level response of vegetation production to warming climate between grassland and forest. Given that many terrestrial ecosystem models use average daily temperature as input, predictions of ecosystem production should consider these contrasting responses to more hot temperature extreme regimes associated with climate change.

  5. Microbial nitrogen cycling response to forest-based bioenergy production.

    PubMed

    Minick, Kevan J; Strahm, Brian D; Fox, Thomas R; Sucre, Eric B; Leggett, Zakiya H

    2015-12-01

    Concern over rising atmospheric CO2 and other greenhouse gases due to fossil fuel combustion has intensified research into carbon-neutral energy production. Approximately 15.8 million ha of pine plantations exist across the southeastern United States, representing a vast land area advantageous for bioenergy production without significant landuse change or diversion of agricultural resources from food production. Furthermore, intercropping of pine with bioenergy grasses could provide annually harvestable, lignocellulosic biomass feedstocks along with production of traditional wood products. Viability of such a system hinges in part on soil nitrogen (N) availability and effects of N competition between pines and grasses on ecosystem productivity. We investigated effects of intercropping loblolly pine (Pinus taeda) with switchgrass (Panicum virgatum) on microbial N cycling processes in the Lower Coastal Plain of North Carolina, USA. Soil samples were collected from bedded rows of pine and interbed space of two treatments, composed of either volunteer native woody and herbaceous vegetation (pine-native) or pure switchgrass (pine-switchgrass) in interbeds. An in vitro 15N pool-dilution technique was employed to quantify gross N transformations at two soil depths (0-5 and 5-15 cm) on four dates in 2012-2013. At the 0-5 cm depth in beds of the pine-switchgrass treatment, gross N mineralization was two to three times higher in November and February compared to the pine-native treatment, resulting in increased NH4(+) availability. Gross and net nitrification were also significantly higher in February in the same pine beds. In interbeds of the pine-switchgrass treatment, gross N mineralization was lower from April to November, but higher in February, potentially reflecting positive effects of switchgrass root-derived C inputs during dormancy on microbial activity. These findings indicate soil N cycling and availability has increased in pine beds of the pine

  6. Forest response to elevated CO2 is conserved across a broad range of productivity

    SciTech Connect

    Norby, Richard J; DeLucia, E. H.; Gielen, Birgit; Califapietra, Carlo; Giardina, Christian P; King, John S.; Childs, Joanne; McCarthy, Heather R; Moore, D J; Ceulemans, Reinhart; DeAngelis, Paolo; Finzi, Adrien C; Karnosky, David; Kubiske, Mark E; Lukac, Martin; Pregitzer, Kurt; Scarascia-Mugnozza, Giuseppe E; Oren, Ram; Schlesinger, William H

    2005-12-01

    Climate change predictions derived from coupled carbon-climate models are highly dependent on assumptions about feedbacks between the biosphere and atmosphere. One critical feedback occurs if C uptake by the biosphere increases in response to the fossil-fuel driven increase in atmospheric [CO2] ('CO2 fertilization'), thereby slowing the rate of increase in atmospheric [CO2]. Carbon exchanges between the terrestrial biosphere and atmosphere are often first represented in models as net primary productivity (NPP). However, the contribution of CO2 fertilization to the future global C cycle has been uncertain, especially in forest ecosystems that dominate global NPP, and models that include a feedback between terrestrial biosphere metabolism and atmospheric [CO2] are poorly constrained by experimental evidence. We analyzed the response of NPP to elevated CO2 ({approx}550 ppm) in four free-air CO2 enrichment experiments in forest stands. We show that the response of forest NPP to elevated [CO2] is highly conserved across a broad range of productivity, with a stimulation at the median of 23 {+-} 2%. At low leaf area indices, a large portion of the response was attributable to increased light absorption, but as leaf area indices increased, the response to elevated [CO2] was wholly caused by increased light-use efficiency. The surprising consistency of response across diverse sites provides a benchmark to evaluate predictions of ecosystem and global models and allows us now to focus on unresolved questions about carbon partitioning and retention, and spatial variation in NPP response caused by availability of other growth limiting resources.

  7. Divergence in Forest-Type Response to Climate and Weather: Evidence for Regional Links Between Forest-Type Evenness and Net Primary Productivity

    USGS Publications Warehouse

    Bradford, J.B.

    2011-01-01

    Climate change is altering long-term climatic conditions and increasing the magnitude of weather fluctuations. Assessing the consequences of these changes for terrestrial ecosystems requires understanding how different vegetation types respond to climate and weather. This study examined 20 years of regional-scale remotely sensed net primary productivity (NPP) in forests of the northern Lake States to identify how the relationship between NPP and climate or weather differ among forest types, and if NPP patterns are influenced by landscape-scale evenness of forest-type abundance. These results underscore the positive relationship between temperature and NPP. Importantly, these results indicate significant differences among broadly defined forest types in response to both climate and weather. Essentially all weather variables that were strongly related to annual NPP displayed significant differences among forest types, suggesting complementarity in response to environmental fluctuations. In addition, this study found that forest-type evenness (within 8 ?? 8 km2 areas) is positively related to long-term NPP mean and negatively related to NPP variability, suggesting that NPP in pixels with greater forest-type evenness is both higher and more stable through time. This is landscape- to subcontinental-scale evidence of a relationship between primary productivity and one measure of biological diversity. These results imply that anthropogenic or natural processes that influence the proportional abundance of forest types within landscapes may influence long-term productivity patterns. ?? 2011 Springer Science+Business Media, LLC (outside the USA).

  8. Fine-root production dominates response of a deciduous forest to atmospheric CO2 enrichment

    PubMed Central

    Norby, Richard J.; Ledford, Joanne; Reilly, Carolyn D.; Miller, Nicole E.; O'Neill, Elizabeth G.

    2004-01-01

    Fine-root production and turnover are important regulators of the biogeochemical cycles of ecosystems and key components of their response to global change. We present a nearly continuous 6-year record of fine-root production and mortality from minirhizotron analysis of a closed-canopy, deciduous sweetgum forest in a free-air CO2 enrichment experiment. Annual production of fine roots was more than doubled in plots with 550 ppm CO2 compared with plots in ambient air. This response was the primary component of the sustained 22% increase in net primary productivity. Annual fine-root mortality matched annual production, and the mean residence time of roots was not altered by elevated CO2, but peak fine-root standing crop in midsummer was significantly higher in CO2-enriched plots, especially deeper in the soil profile. The preferential allocation of additional carbon to fine roots, which have a fast turnover rate in this species, rather than to stemwood reduces the possibility of long-term enhancement by elevated CO2 of carbon sequestration in biomass. However, sequestration of some of the fine-root carbon in soil pools is not precluded, and there may be other benefits to the tree from a seasonally larger and deeper fine-root system. Root-system dynamics can explain differences among ecosystems in their response to elevated atmospheric CO2; hence, accurate assessments of carbon flux and storage in forests in a globally changing atmosphere must account for this unseen and difficult-to-measure component. PMID:15210962

  9. Fine-root production dominates response of a deciduous forest to atmospheric CO2 enrichment.

    PubMed

    Norby, Richard J; Ledford, Joanne; Reilly, Carolyn D; Miller, Nicole E; O'Neill, Elizabeth G

    2004-06-29

    Fine-root production and turnover are important regulators of the biogeochemical cycles of ecosystems and key components of their response to global change. We present a nearly continuous 6-year record of fine-root production and mortality from minirhizotron analysis of a closed-canopy, deciduous sweetgum forest in a free-air CO(2) enrichment experiment. Annual production of fine roots was more than doubled in plots with 550 ppm CO(2) compared with plots in ambient air. This response was the primary component of the sustained 22% increase in net primary productivity. Annual fine-root mortality matched annual production, and the mean residence time of roots was not altered by elevated CO(2), but peak fine-root standing crop in midsummer was significantly higher in CO(2)-enriched plots, especially deeper in the soil profile. The preferential allocation of additional carbon to fine roots, which have a fast turnover rate in this species, rather than to stemwood reduces the possibility of long-term enhancement by elevated CO(2) of carbon sequestration in biomass. However, sequestration of some of the fine-root carbon in soil pools is not precluded, and there may be other benefits to the tree from a seasonally larger and deeper fine-root system. Root-system dynamics can explain differences among ecosystems in their response to elevated atmospheric CO(2); hence, accurate assessments of carbon flux and storage in forests in a globally changing atmosphere must account for this unseen and difficult-to-measure component. PMID:15210962

  10. Modelling climate change responses in tropical forests: similar productivity estimates across five models, but different mechanisms and responses

    NASA Astrophysics Data System (ADS)

    Rowland, L.; Harper, A.; Christoffersen, B. O.; Galbraith, D. R.; Imbuzeiro, H. M. A.; Powell, T. L.; Doughty, C.; Levine, N. M.; Malhi, Y.; Saleska, S. R.; Moorcroft, P. R.; Meir, P.; Williams, M.

    2014-11-01

    Accurately predicting the response of Amazonia to climate change is important for predicting changes across the globe. However, changes in multiple climatic factors simultaneously may result in complex non-linear responses, which are difficult to predict using vegetation models. Using leaf and canopy scale observations, this study evaluated the capability of five vegetation models (CLM3.5, ED2, JULES, SiB3, and SPA) to simulate the responses of canopy and leaf scale productivity to changes in temperature and drought in an Amazonian forest. The models did not agree as to whether gross primary productivity (GPP) was more sensitive to changes in temperature or precipitation. There was greater model-data consistency in the response of net ecosystem exchange to changes in temperature, than in the response to temperature of leaf area index (LAI), net photosynthesis (An) and stomatal conductance (gs). Modelled canopy scale fluxes are calculated by scaling leaf scale fluxes to LAI, and therefore in this study similarities in modelled ecosystem scale responses to drought and temperature were the result of inconsistent leaf scale and LAI responses among models. Across the models, the response of An to temperature was more closely linked to stomatal behaviour than biochemical processes. Consequently all the models predicted that GPP would be higher if tropical forests were 5 °C colder, closer to the model optima for gs. There was however no model consistency in the response of the An-gs relationship when temperature changes and drought were introduced simultaneously. The inconsistencies in the An-gs relationships amongst models were caused by to non-linear model responses induced by simultaneous drought and temperature change. To improve the reliability of simulations of the response of Amazonian rainforest to climate change the mechanistic underpinnings of vegetation models need more complete validation to improve accuracy and consistency in the scaling of processes from

  11. Rational forest productivity decline.

    PubMed

    MacLellan, James I; Carleton, T J

    2003-01-01

    A whole forest optimisation model was employed to examine economic behaviour as it relates to long term, forest productivity decline in the boreal forests of Ontario, Canada. Our productivity investment model (PIM) incorporated a choice between productivity decline as represented by a drop in forest Site Class, and a fee to 'maintain' site productivity. Sensitivity analysis was used to determine the point at which these fees exceeded the value of the differential in timber volume between upper and lower site classes. By varying discount rate, 'productivity investment frontiers' were constructed, which highlight the effects of the magnitude in productivity decline, maintenance fees, and harvest flow constraints upon the occurrence and schedule of productivity declines. In presenting this simple approach to exploring the effects of economic choice upon forest productivity decline, the phenomena of 'natural capital divestment' within forestry is described. PMID:12859006

  12. Modelling climate change responses in tropical forests: similar productivity estimates across five models, but different mechanisms and responses

    NASA Astrophysics Data System (ADS)

    Rowland, L.; Harper, A.; Christoffersen, B. O.; Galbraith, D. R.; Imbuzeiro, H. M. A.; Powell, T. L.; Doughty, C.; Levine, N. M.; Malhi, Y.; Saleska, S. R.; Moorcroft, P. R.; Meir, P.; Williams, M.

    2015-04-01

    Accurately predicting the response of Amazonia to climate change is important for predicting climate change across the globe. Changes in multiple climatic factors simultaneously result in complex non-linear ecosystem responses, which are difficult to predict using vegetation models. Using leaf- and canopy-scale observations, this study evaluated the capability of five vegetation models (Community Land Model version 3.5 coupled to the Dynamic Global Vegetation model - CLM3.5-DGVM; Ecosystem Demography model version 2 - ED2; the Joint UK Land Environment Simulator version 2.1 - JULES; Simple Biosphere model version 3 - SiB3; and the soil-plant-atmosphere model - SPA) to simulate the responses of leaf- and canopy-scale productivity to changes in temperature and drought in an Amazonian forest. The models did not agree as to whether gross primary productivity (GPP) was more sensitive to changes in temperature or precipitation, but all the models were consistent with the prediction that GPP would be higher if tropical forests were 5 °C cooler than current ambient temperatures. There was greater model-data consistency in the response of net ecosystem exchange (NEE) to changes in temperature than in the response to temperature by net photosynthesis (An), stomatal conductance (gs) and leaf area index (LAI). Modelled canopy-scale fluxes are calculated by scaling leaf-scale fluxes using LAI. At the leaf-scale, the models did not agree on the temperature or magnitude of the optimum points of An, Vcmax or gs, and model variation in these parameters was compensated for by variations in the absolute magnitude of simulated LAI and how it altered with temperature. Across the models, there was, however, consistency in two leaf-scale responses: (1) change in An with temperature was more closely linked to stomatal behaviour than biochemical processes; and (2) intrinsic water use efficiency (IWUE) increased with temperature, especially when combined with drought. These results suggest

  13. Net primary production of a temperate deciduous forest exhibits a threshold response to increasing disturbance severity.

    PubMed

    Stuart-Haëntjens, Ellen J; Curtis, Peter S; Fahey, Robert T; Vogel, Christoph S; Gough, Christopher M

    2015-09-01

    The global carbon (C) balance is vulnerable to disturbances that alter terrestrial C storage. Disturbances to forests occur along a continuum of severity, from low-intensity disturbance causing the mortality or defoliation of only a subset of trees to severe stand- replacing disturbance that kills all trees; yet considerable uncertainty remains in how forest production changes across gradients of disturbance intensity. We used a gradient of tree mortality in an upper Great Lakes forest ecosystem to: (1) quantify how aboveground wood net primary production (ANPP,) responds to a range of disturbance severities; and (2) identify mechanisms supporting ANPPw resistance or resilience following moderate disturbance. We found that ANPPw declined nonlinearly with rising disturbance severity, remaining stable until >60% of the total tree basal area senesced. As upper canopy openness increased from disturbance, greater light availability to the subcanopy enhanced the leaf-level photosynthesis and growth of this formerly light-limited canopy stratum, compensating for upper canopy production losses and a reduction in total leaf area index (LAI). As a result, whole-ecosystem production efficiency (ANPPw/LAI) increased with rising disturbance severity, except in plots beyond the disturbance threshold. These findings provide a mechanistic explanation for a nonlinear relationship between ANPPw, and disturbance severity, in which the physiological and growth enhancement of undisturbed vegetation is proportional to the level of disturbance until a threshold is exceeded. Our results have important ecological and management implications, demonstrating that in some ecosystems moderate levels of disturbance minimally alter forest production. PMID:26594704

  14. Forest response to elevated CO2 is conserved across a broad range of productivity

    SciTech Connect

    Norby, Richard J; DeLucia, E. H.; Gielen, Birgit; Califapietra, Carlo; Giardina, Christian P; King, John S.; Childs, Joanne; McCarthy, Heather R; Moore, D J; Ceulemans, Reinhart; DeAngelis, Paolo; Finzi, Adrien C; Karnosky, David; Kubiske, Mark E; Lukac, Martin; Pregitzer, Kurt; Scarascia-Mugnozza, Giuseppe E; Schlesinger, William H; Oren, Ram

    2005-11-01

    Climate change predictions derived from coupled carbon-climate models are highly dependent on assumptions about feedbacks between the biosphere and atmosphere. One critical feedback occurs if C uptake by the biosphere increases in response to the fossil-fuel driven increase in atmospheric [CO{sub 2}] ('CO{sub 2} fertilization'), thereby slowing the rate of increase in atmospheric [CO{sub 2}]. Carbon exchanges between the terrestrial biosphere and atmosphere are often first represented in models as net primary productivity (NPP). However, the contribution of CO{sub 2} fertilization to the future global C cycle has been uncertain, especially in forest ecosystems that dominate global NPP, and models that include a feedback between terrestrial biosphere metabolism and atmospheric [CO{sub 2}] are poorly constrained by experimental evidence. We analyzed the response of NPP to elevated CO{sub 2} ({approx}550 ppm) in four free-air CO{sub 2} enrichment experiments in forest stands. We show that the response of forest NPP to elevated [CO{sub 2}] is highly conserved across a broad range of productivity, with a stimulation at the median of 23 {+-} 2%. At low leaf area indices, a large portion of the response was attributable to increased light absorption, but as leaf area indices increased, the response to elevated [CO{sub 2}] was wholly caused by increased light-use efficiency. The surprising consistency of response across diverse sites provides a benchmark to evaluate predictions of ecosystem and global models and allows us now to focus on unresolved questions about carbon partitioning and retention, and spatial variation in NPP response caused by availability of other growth limiting resources.

  15. Hybrid poplar and forest soil response to municipal and industrial by-products: a greenhouse study.

    PubMed

    Cavaleri, Molly A; Gilmore, Daniel W; Mozaffari, Morteza; Rosen, Carl J; Halbach, Thomas R

    2004-01-01

    Little research has been conducted in the Lake States (Minnesota, Wisconsin, and Michigan) to evaluate the effects of municipal and industrial by-product applications on the early growth of short rotation woody crops such as hybrid poplar. Anticipated shortages of harvestable-age aspen in the next decade can be alleviated and rural development can be enhanced through the application of by-products to forest soils. This study was conducted to evaluate the effects of inorganic fertilizer, boiler ash, biosolids, and the co-application of ash and biosolids application on tree growth and soil properties by measuring hybrid poplar clone NM-6 (Populus nigra L. x P. maximowiczii A. Henry) yield, nutrient uptake, and select post-harvest soil properties after 15 wk of greenhouse growth. Treatments included a control of no amendment; agricultural lime; inorganic N, P, and K; three types of boiler ash; biosolids application rates equivalent to 70, 140, 210, and 280 kg available N ha(-1); and boiler ash co-applied with biosolids. All of the by-products treatments showed biomass production that was equal to or greater than inorganic fertilizer and lime treatments. A trend of increased biomass with increasing rates of biosolids was observed. Soil P concentration increased with increasing rates of biosolids application. None of the by-products treatments resulted in plant tissue metal concentrations greater than metal concentrations of plant tissue amended with inorganic amendments. Biosolids, boiler ash, and the co-application of biosolids and boiler ash together on forest soils were as beneficial to plant growth as inorganic fertilizers. PMID:15224944

  16. Forest fine-root production and nitrogen use under elevated CO2: Contrasting responses explained by a common principle

    SciTech Connect

    Franklin, Oscar; McMurtrie, Ross E; Iversen, Colleen M; Crous, Kristine; Finzi, Adrien C; Tissue, David Thomas; Ellsworth, David; Oren, Ram; Norby, Richard J

    2009-01-01

    Despite the importance of nitrogen (N) limitation of forest carbon (C) sequestration at rising atmospheric CO2 concentration, the mechanisms responsible are not well understood. To elucidate the interactive effects of elevated CO2 (eCO2) and soil N availability on forest productivity and C allocation, we hypothesized that 1) trees maximize fitness by allocating N and C to maximize their net growth, and 2) that N uptake is controlled by root exploration for N. We tested this model using data collected in FACE sites dominated by evergreen (Pinus taeda; Duke Forest) and deciduous (Liquidambar styraciflua; Oak Ridge National Laboratory ORNL) trees. The model explained 80-95% of variation in productivity and N-uptake data among eCO2, N fertilization and control treatments over six years. The model explains why fine-root production increased, and why N uptake increased despite reduced soil N availability under eCO2 at ORNL and Duke. In agreement with observations at other sites, soil N availability reduced below a critical level diminishes all eCO2 responses. At Duke, a negative feedback between reduced soil N availability and N uptake counteracted progressive reduction in soil N availability at eCO2. At ORNL, decreasing soil N availability was perpetuated as it generated no reduction in N uptake, due to strongly increased production of fast turnover fine-roots. This implies that species with fast root turnover could be more prone to progressive N limitation of carbon sequestration in woody biomass than species with slow root turnover, such as evergreens.

  17. Forest Products Industry Technology Roadmap

    SciTech Connect

    none,

    2010-04-01

    This document describes the forest products industry's research and development priorities. The original technology roadmap published by the industry in 1999 and was most recently updated in April 2010.

  18. 29 CFR 780.159 - Forest products.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Forest products. 780.159 Section 780.159 Labor Regulations... Other Unlisted Practices Which May Be within Section 3(f) § 780.159 Forest products. Trees grown in forests and the lumber derived therefrom are not agricultural or horticultural commodities, for...

  19. 29 CFR 780.115 - Forest products.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Forest products. 780.115 Section 780.115 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY OR... Agricultural Or Horticultural Commodities § 780.115 Forest products. Trees grown in forests and the...

  20. 29 CFR 780.115 - Forest products.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 3 2014-07-01 2014-07-01 false Forest products. 780.115 Section 780.115 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY OR... Agricultural Or Horticultural Commodities § 780.115 Forest products. Trees grown in forests and the...

  1. 29 CFR 780.159 - Forest products.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false Forest products. 780.159 Section 780.159 Labor Regulations... Other Unlisted Practices Which May Be within Section 3(f) § 780.159 Forest products. Trees grown in forests and the lumber derived therefrom are not agricultural or horticultural commodities, for...

  2. 29 CFR 780.115 - Forest products.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false Forest products. 780.115 Section 780.115 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY OR... Agricultural Or Horticultural Commodities § 780.115 Forest products. Trees grown in forests and the...

  3. 29 CFR 780.159 - Forest products.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 3 2014-07-01 2014-07-01 false Forest products. 780.159 Section 780.159 Labor Regulations... Other Unlisted Practices Which May Be within Section 3(f) § 780.159 Forest products. Trees grown in forests and the lumber derived therefrom are not agricultural or horticultural commodities, for...

  4. 29 CFR 780.159 - Forest products.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false Forest products. 780.159 Section 780.159 Labor Regulations... Other Unlisted Practices Which May Be within Section 3(f) § 780.159 Forest products. Trees grown in forests and the lumber derived therefrom are not agricultural or horticultural commodities, for...

  5. 29 CFR 780.159 - Forest products.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Forest products. 780.159 Section 780.159 Labor Regulations... Other Unlisted Practices Which May Be within Section 3(f) § 780.159 Forest products. Trees grown in forests and the lumber derived therefrom are not agricultural or horticultural commodities, for...

  6. 29 CFR 780.115 - Forest products.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Forest products. 780.115 Section 780.115 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY OR... Agricultural Or Horticultural Commodities § 780.115 Forest products. Trees grown in forests and the...

  7. 29 CFR 780.115 - Forest products.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false Forest products. 780.115 Section 780.115 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY OR... Agricultural Or Horticultural Commodities § 780.115 Forest products. Trees grown in forests and the...

  8. Method of determining forest production from remotely sensed forest parameters

    DOEpatents

    Corey, J.C.; Mackey, H.E. Jr.

    1987-08-31

    A method of determining forest production entirely from remotely sensed data in which remotely sensed multispectral scanner (MSS) data on forest 5 composition is combined with remotely sensed radar imaging data on forest stand biophysical parameters to provide a measure of forest production. A high correlation has been found to exist between the remotely sensed radar imaging data and on site measurements of biophysical 10 parameters such as stand height, diameter at breast height, total tree height, mean area per tree, and timber stand volume.

  9. A Novel Tropical Dry Forests: A Response to Environmental Change.

    NASA Astrophysics Data System (ADS)

    Lugo, A. E.; Molina, S.

    2015-12-01

    Dry Forest environments are favorable to human settlement and activities, leading to deforestation, agricultural enterprises, land degradation, and abandonment. As a result, tropical dry forests are vulnerable and experience a high rate of cover loss, which often requires restoration activities. We have studied the natural regeneration of dry forests in Puerto Rico following a variety of human activities including farming, cattle pasturing, charcoal production, and human dwellings. Our results show a high level of forest resilience to anthropogenic disturbances but also a change of species composition relative to undisturbed native forests. This novelty of forest composition represents a natural response to environmental changes induced by human activity and pre-adapts forests to conditions in the Anthropocene.

  10. 36 CFR 223.216 - Special Forest Products definitions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Special Forest Products definitions. 223.216 Section 223.216 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST...

  11. 36 CFR 223.216 - Special Forest Products definitions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Special Forest Products definitions. 223.216 Section 223.216 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST...

  12. 36 CFR 223.277 - Forest botanical products definition.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Forest botanical products definition. 223.277 Section 223.277 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST...

  13. 36 CFR 223.277 - Forest botanical products definition.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Forest botanical products definition. 223.277 Section 223.277 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST...

  14. 36 CFR 223.216 - Special Forest Products definitions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Special Forest Products definitions. 223.216 Section 223.216 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST...

  15. 36 CFR 223.277 - Forest botanical products definition.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Forest botanical products definition. 223.277 Section 223.277 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST...

  16. 36 CFR 223.277 - Forest botanical products definition.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Forest botanical products definition. 223.277 Section 223.277 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST...

  17. 36 CFR 223.216 - Special Forest Products definitions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Special Forest Products definitions. 223.216 Section 223.216 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST...

  18. Climate Change Impacts on Forest Succession and Future Productivity

    NASA Astrophysics Data System (ADS)

    Mohan, J. E.; Melillo, J. M.; Clark, J. S.; Schlesinger, W. H.

    2012-12-01

    Change in ecosystem carbon (C) dynamics with forest succession is a long-studied topic in ecology, and secondary forests currently comprise a significant proportion of the global land base. Although mature forests are generally more important for conserving species and habitats, early successional trees and stands typically have higher rates of productivity, including net ecosystem productivity (NEP), which represents carbon available for sequestration. Secondary forests undergoing successional development are thus major players in the current global carbon cycle, yet how forests will function in the future under warmer conditions with higher atmospheric carbon dioxide (CO2) concentrations is unknown. Future forest C dynamics will depend, in part, on future species composition. Data from "Forests of the Future" research in a number of global change experiments provide insights into how forests may look in terms of dominant species composition, and thus function, in a future world. Studies at Free-Air Carbon Dioxide (FACE) experiments at Duke Forest and other facilities, plus climate warming experiments such as those at the Harvard Forest, suggest a common underlying principle of vegetation responses to environmental manipulation: Namely, that shade-tolerant woody species associating with arbuscular mycorrhizal (AM) fungi show greater growth stimulation than ectomycorrhizal-associating (ECM) trees which are more common in temperate and boreal forests (Fig. 1 of relative growth rates standardized by pre-treatment rates). This may be due in part to the role of AM fungi in obtaining soil phosphorus and inorganic forms of nitrogen for plant associates. In combination, these results suggest a shift in future forest composition towards less-productive tree species that generally acquire atmospheric CO2 at lower annual rates, as well as a competitive advantage extended to woody vines such as poison ivy. Due to higher atmospheric CO2 and warmer temperatures, forests of the

  19. Response of the Fine Root Production, Phenology, and Turnover Rate of Six Shrub Species from a Subtropical Forest to a Soil Moisture Gradient and Shading

    NASA Astrophysics Data System (ADS)

    Fu, X.; Dai, X.; Wang, H.

    2015-12-01

    Knowledge of the fine root dynamics of different life forms in forest ecosystems is critical to understanding how the overall belowground carbon cycling is affected by climate change. However, our current knowledge regarding how endogenous or exogenous factors regulate the root dynamics of understory vegetation is limited. We selected a suite of study sites representing different habitats with gradients of soil moisture and solar radiation (shading or no shading). We assessed the fine root production phenology, the total fine root production, and the turnover among six understory shrub species in a subtropical climate, and examined the responses of the fine root dynamics to gradients in the soil moisture and solar radiation. The shrubs included three evergreen species, Loropetalum chinense, Vaccinium bracteatum, and Adinandra millettii, and three deciduous species, Serissa serissoides, Rubus corchorifolius, and Lespedeza davidii. We observed that variations in the annual fine root production and turnover among species were significant in the deciduous group but not in the evergreen group. Notably, V. bracteatum and S. serissoides presented the greatest responses in terms of root phenology to gradients in the soil moisture and shading: high-moisture habitat led to a decrease and shade led to an increase in fine root production during spring. Species with smaller fine roots of the 1st+2nd-order diameter presented more sensitive responses in terms of fine root phenology to a soil moisture gradient. Species with a higher fine root nitrogen-to -carbon ratio exhibited more sensitive responses in terms of fine root annual production to shading. Soil moisture and shading did not change the annual fine root production as much as the turnover rate. The fine root dynamics of some understory shrubs varied significantly with soil moisture and solar radiation status and may be different from tree species. Our results emphasize the need to study the understory fine root dynamics

  20. Forest response and recovery following disturbance (Invited)

    NASA Astrophysics Data System (ADS)

    Schafer, K. V.; Clark, K. L.; Renninger, H. J.; Carlo, N.; Medvigy, D.

    2013-12-01

    Forest management and global climate change may modulate forest responses to disturbances such as drought, insect infestation or windthrow. Forest responses to drought and gypsy moth defoliation measured from 2005 to present in an oak/pine ecosystem in the Atlantic Coastal Plain (New Jersey Pinelands) show a relative conservatism of water use but longer lasting effects on carbon balance. While post-defoliation transpiration and evapotranspiration were similar to pre-defoliation levels, post-defoliation carbon fluxes have not returned to pre-disturbance levels even after five years of recovery due to a 25% reduction in basal area following tree mortality. Defoliation frequency also affects recovery with modeled carbon fluxes under various defoliation scenarios, showing pronounced reduction in productivity under frequent defoliation, but no effect if defoliation occurs at a rate of less than 15 years. Despite a relatively consistent seasonal water use through various disturbances, defoliation and drought affect water use differently. For example, canopy transpiration (EC) after defoliation and subsequent re-sprouting, was reduced by 25% compared to pre-defoliation levels, even though only half of the leaf area was replaced. However under severe drought conditions in 2006 and 2010, EC was only reduced by 8% and 18% respectively. Therefore, prolonged drought had a lesser effect on EC than reduced foliage or episodic defoliation, suggesting these trees have access to deeper soil moisture. These data also suggest that defoliation may make trees more sensitive to drought as evidenced by the higher reduction of Ec in 2010 compared to 2006 (pre-defoliation). Differential physiological responses of the various oak species as well as pitch pine may also create a species shift in an ecosystem that is also prone to fire. In this ecosystem, Quercus prinus showed consistently lower stomatal conductance, photosynthesis and maximum carboxylation rate compared to Quercus velutina

  1. Contribution of Near Real Time MODIS-Based Forest Disturbance Detection Products to a National Forest Threat Early Warning System

    NASA Technical Reports Server (NTRS)

    Spruce, Joseph; Hargrove, William; Gasser, Gerald; Smoot, James; Kuper, Philip

    2011-01-01

    U.S. forests occupy approx. 751 million acres (approx. 1/3 of total land). These forests are exposed to multiple biotic and abiotic threats that collectively damage extensive acreages each year. Hazardous forest disturbances can threaten human life and property, bio-diversity and water supplies. Timely regional forest monitoring products are needed to aid forest management and decision making by the US Forest Service and its state and private partners. Daily MODIS data products provide a means to monitor regional forest disturbances on a weekly basis. In response, we began work in 2006 to develop a Near Real Time (NRT) forest monitoring capability, based on MODIS NDVI data, as part of a national forest threat early warning system (EWS)

  2. Forest biogeochemistry in response to drought.

    PubMed

    Schlesinger, William H; Dietze, Michael C; Jackson, Robert B; Phillips, Richard P; Rhoades, Charles C; Rustad, Lindsey E; Vose, James M

    2016-07-01

    Trees alter their use and allocation of nutrients in response to drought, and changes in soil nutrient cycling and trace gas flux (N2 O and CH4 ) are observed when experimental drought is imposed on forests. In extreme droughts, trees are increasingly susceptible to attack by pests and pathogens, which can lead to major changes in nutrient flux to the soil. Extreme droughts often lead to more common and more intense forest fires, causing dramatic changes in the nutrient storage and loss from forest ecosystems. Changes in the future manifestation of drought will affect carbon uptake and storage in forests, leading to feedbacks to the Earth's climate system. We must improve the recognition of drought in nature, our ability to manage our forests in the face of drought, and the parameterization of drought in earth system models for improved predictions of carbon uptake and storage in the world's forests. PMID:26403995

  3. 36 CFR 223.277 - Forest botanical products definition.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Forest botanical products definition. 223.277 Section 223.277 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER Forest Botanical Products § 223.277...

  4. 36 CFR 223.216 - Special Forest Products definitions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Special Forest Products definitions. 223.216 Section 223.216 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER Special Forest Products § 223.216...

  5. Classifying forest productivity at different scales

    SciTech Connect

    Graham, R.L.

    1991-01-01

    Spatial scale is an important consideration when evaluating, using, or constructing forest productivity classifications. First, the factors which dominate spatial variability in forest productivity are scale dependent. For example, within a stand, spatial variability in productivity is dominated by microsite differences; within a national forest such as the Cherokee National Forest, spatial variability is dominated by topography and land-use history (e.g., years since harvest); within a large region such as the southeast, spatial variability is dominated by climatic patterns. Second, classifications developed at different spatial scales are often used for different purposes. For example, stand-level classifications are often keys or rules used in the field to judge the quality or potential of a site. National-forest classifications are often presented as maps or tables and may be used in forest land planning. Regional classifications may be maps or tables and may be used to quantify or predict resource availability. These scale-related differences in controlling factors and purposes will affect both the methods and the data used to develop classifications. In this paper, I will illustrate these points by describing and comparing three forest productivity classifications, each developed for a specific purpose at a specific scale. My objective is not to argue for or against any of these particular classifications but rather to heighten awareness of the critical role that spatial scale plays in the use and development of forest productivity classifications. 8 refs., 2 figs., 1 tab.

  6. Water management and productivity in planted forests

    NASA Astrophysics Data System (ADS)

    Nettles, J. E.

    2014-09-01

    As climate variability endangers water security in many parts of the world, maximizing the carbon balance of plantation forestry is of global importance. High plant water use efficiency is generally associated with lower plant productivity, so an explicit balance in resources is necessary to optimize water yield and tree growth. This balance requires predicting plant water use under different soil, climate, and planting conditions, as well as a mechanism to account for trade-offs in ecosystem services. Several strategies for reducing the water use of forests have been published but there is little research tying these to operational forestry. Using data from silvicultural and biofuel feedstock research in pine plantation ownership in the southeastern USA, proposed water management tools were evaluated against known treatment responses to estimate water yield, forest productivity, and economic outcomes. Ecosystem impacts were considered qualitatively and related to water use metrics. This work is an attempt to measure and compare important variables to make sound decisions about plantations and water use.

  7. Comparison of simulated forest responses to biosolids application

    SciTech Connect

    Luxmoore, R.J.; Tharp, M.L.; Efroymson, R.A.

    1999-12-01

    Organic matter and N are added to humus pools of the LINKAGES simulator of forest growth and N cycling at a range of application rates to investigate long-term effects of biosolids (sewage sludge) on forest productivity. Two conifer plantations (Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco var. menziesii], loblolly pine [Pinus taeda L.]) and a northern hardwood forest located in contrasting climatic regions are investigated. Single applications of biosolids are given at 0.5, 10, 20, and 40 Mg/ha, and multiple applications are given on seven occasions at 3-yr intervals of rates of 5 and 10 Mg/ha. Highly significant increases in aboveground phytomass and net primary productivity of Douglas-fir plantations are obtained in a 100-yr simulation with increasing biosolids application rates. Results for loblolly pine from a 50-yr simulation produced about half the growth response of Douglas-fir. Long-term simulations of northern hardwoods showed modest growth responses and small increases in NPP with added biosolids. The phytomass of one overstory and three understory species in the hardwood forest changed in response to different biosolids applications and varying species sensitivity to N supply. Biosolids are a significant resource for enhancing forest productivity, particularly in conifer plantations. Estimates of N leaching losses from simulated forest sites combined with a literature review of leaching losses suggest that biosolids applications at 3-yr intervals with rates less than 8.5 Mg/ha (0.4 Mg N/ha) during active forest growth may pose little off-site contamination risk to ground water or surface waters.

  8. 78 FR 34031 - Burned Area Emergency Response, Forest Service

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-06

    ... Response activities on National Forest System lands. Agency regulations at 36 CFR 220.6(d)(2) (73 FR 43093...; ] DEPARTMENT OF AGRICULTURE Forest Service RIN 0596-AC73 Burned Area Emergency Response, Forest Service AGENCY: Forest Service, USDA. ACTION: Notice of interim directive; request for public comment. SUMMARY:...

  9. Modeling Forest Productivity Using Envisat MERIS Data

    PubMed Central

    Berberoglu, Suha; Evrendilek, Fatih; Ozkan, Coskun; Donmez, Cenk

    2007-01-01

    The aim of this study was to derive land cover products with a 300-m pixel resolution of Envisat MERIS (Medium Resolution Imaging Spectrometer) to quantify net primary productivity (NPP) of conifer forests of Taurus Mountain range along the Eastern Mediterranean coast of Turkey. The Carnegie-Ames-Stanford approach (CASA) was used to predict annual and monthly regional NPP as modified by temperature, precipitation, solar radiation, soil texture, fractional tree cover, land cover type, and normalized difference vegetation index (NDVI). Fractional tree cover was estimated using continuous training data and multi-temporal metrics of 47 Envisat MERIS images of March 2003 to September 2005 and was derived by aggregating tree cover estimates made from high-resolution IKONOS imagery to coarser Landsat ETM imagery. A regression tree algorithm was used to estimate response variables of fractional tree cover based on the multi-temporal metrics. This study showed that Envisat MERIS data yield a greater spatial detail in the quantification of NPP over a topographically complex terrain at the regional scale than those used at the global scale such as AVHRR.

  10. Amazon Forest Responses to Drought and Fire

    NASA Astrophysics Data System (ADS)

    Morton, D. C.

    2015-12-01

    Deforestation and agricultural land uses provide a consistent source of ignitions along the Amazon frontier during the dry season. The risk of understory fires in Amazon forests is amplified by drought conditions, when fires at the forest edge may spread for weeks before rains begin. Fire activity also impacts the regional response of intact forests to drought through diffuse light effects and nutrient redistribution, highlighting the complexity of feedbacks in this coupled human and natural system. This talk will focus on recent advances in our understanding of fire-climate feedbacks in the Amazon, building on research themes initiated under NASA's Large-scale Biosphere-Atmosphere Experiment in Amazonia (LBA). NASA's LBA program began in the wake of the 1997-1998 El Niño, a strong event that exposed the vulnerability of Amazon forests to drought and fire under current climate and projections of climate change. With forecasts of another strong El Niño event in 2015-2016, this talk will provide a multi-scale synthesis of Amazon forest responses to drought and fire based on field measurements, airborne lidar data, and satellite observations of fires, rainfall, and terrestrial water storage. These studies offer new insights into the mechanisms governing fire season severity in the southern Amazon and regional variability in carbon losses from understory fires. The contributions from remote sensing to our understanding of drought and fire in Amazon forests reflect the legacy of NASA's LBA program and the sustained commitment to interdisciplinary research across the Amazon region.

  11. Sustainable Harvest and marketing of rain forest products

    SciTech Connect

    Plotkin, M.J.; Famolare, L.M.

    1992-01-01

    The economics of nontimber rainforest products often make a strong case for forest protection and prevention of deforestation. This book contains 33 diverse papers falling into three catagories: tropical rainforests are underutilized sources of new plant products; increased use of tropical forest products should benefit human inhabitants of the rainforest; nontimber forest products many not be the panacea that some suggest.

  12. Rapid Increases in forest understory diversity and productivity following a mountain pine beetle (Dendroctonus ponderosae) outbreak in pine forests.

    PubMed

    Pec, Gregory J; Karst, Justine; Sywenky, Alexandra N; Cigan, Paul W; Erbilgin, Nadir; Simard, Suzanne W; Cahill, James F

    2015-01-01

    The current unprecedented outbreak of mountain pine beetle (Dendroctonus ponderosae) in lodgepole pine (Pinus contorta) forests of western Canada has resulted in a landscape consisting of a mosaic of forest stands at different stages of mortality. Within forest stands, understory communities are the reservoir of the majority of plant species diversity and influence the composition of future forests in response to disturbance. Although changes to stand composition following beetle outbreaks are well documented, information on immediate responses of forest understory plant communities is limited. The objective of this study was to examine the effects of D. ponderosae-induced tree mortality on initial changes in diversity and productivity of understory plant communities. We established a total of 110 1-m2 plots across eleven mature lodgepole pine forests to measure changes in understory diversity and productivity as a function of tree mortality and below ground resource availability across multiple years. Overall, understory community diversity and productivity increased across the gradient of increased tree mortality. Richness of herbaceous perennials increased with tree mortality as well as soil moisture and nutrient levels. In contrast, the diversity of woody perennials did not change across the gradient of tree mortality. Understory vegetation, namely herbaceous perennials, showed an immediate response to improved growing conditions caused by increases in tree mortality. How this increased pulse in understory richness and productivity affects future forest trajectories in a novel system is unknown. PMID:25859663

  13. Rapid Increases in Forest Understory Diversity and Productivity following a Mountain Pine Beetle (Dendroctonus ponderosae) Outbreak in Pine Forests

    PubMed Central

    Pec, Gregory J.; Karst, Justine; Sywenky, Alexandra N.; Cigan, Paul W.; Erbilgin, Nadir; Simard, Suzanne W.; Cahill, James F.

    2015-01-01

    The current unprecedented outbreak of mountain pine beetle (Dendroctonus ponderosae) in lodgepole pine (Pinus contorta) forests of western Canada has resulted in a landscape consisting of a mosaic of forest stands at different stages of mortality. Within forest stands, understory communities are the reservoir of the majority of plant species diversity and influence the composition of future forests in response to disturbance. Although changes to stand composition following beetle outbreaks are well documented, information on immediate responses of forest understory plant communities is limited. The objective of this study was to examine the effects of D. ponderosae-induced tree mortality on initial changes in diversity and productivity of understory plant communities. We established a total of 110 1-m2 plots across eleven mature lodgepole pine forests to measure changes in understory diversity and productivity as a function of tree mortality and below ground resource availability across multiple years. Overall, understory community diversity and productivity increased across the gradient of increased tree mortality. Richness of herbaceous perennials increased with tree mortality as well as soil moisture and nutrient levels. In contrast, the diversity of woody perennials did not change across the gradient of tree mortality. Understory vegetation, namely herbaceous perennials, showed an immediate response to improved growing conditions caused by increases in tree mortality. How this increased pulse in understory richness and productivity affects future forest trajectories in a novel system is unknown. PMID:25859663

  14. Where No (Observed) Forest has Gone Before: New Patterns in Forest Response to Climate Change and Variability

    NASA Astrophysics Data System (ADS)

    McNulty, S.; Sun, G.; Boggs, J. L.; Ward, E. J.

    2014-12-01

    Insect outbreaks, wildfire, and drought have directly or indirectly impacted forest health, productivity and water use long before the advent of modern forestry practices. However, climate change may be acerbating these impacts are causing land managers to reconsider the use and timing of management tools. However, even as new methods are being devised to combat negative drought impacts, the forest response to chronic and increasingly severe episodic drought may be changing. Historically, the weakest (e.g., suppressed, understory) trees were the first to succumb to stress while the strongest (e.g., dominant, fast growing). However, recent studies have suggested that a combination of chronic and increasingly extreme episodic stress may be causing hereunto unobserved patterns in forest mortality with the more vigorously growing trees having higher rates of mortality than slower growing, more generally stressed individuals. I suggest that the forests have not altered their response to stress, but only that the level of stress, and the forest response to that stress has not previously been observed in recorded history. This extension of the forest stress response continuum has very significant implications to forest management under drought and associated disturbance. Therefore, this paper explores the causes and implications for maintaining forest resilience and sustainability under an increasingly variable climate.

  15. Developing New Coastal Forest Restoration Products Based on Landsat, ASTER, and MODIS Data

    NASA Technical Reports Server (NTRS)

    Spruce, Joseph P.; Graham, William; Smoot, James

    2009-01-01

    This paper discusses an ongoing effort to develop new geospatial information products for aiding coastal forest restoration and conservation efforts in coastal Louisiana and Mississippi. This project employs Landsat, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), and Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data in conjunction with airborne elevation data to compute coastal forest cover type maps and change detection products. Improved forest mapping products are needed to aid coastal forest restoration and management efforts of State and Federal agencies in the Northern Gulf of Mexico (NGOM) region. In particular, such products may aid coastal forest land acquisition and conservation easement procurements. This region's forests are often disturbed and subjected to multiple biotic and abiotic threats, including subsidence, salt water intrusion, hurricanes, sea-level rise, insect-induced defoliation and mortality, altered hydrology, wildfire, and conversion to non-forest land use. In some cases, such forest disturbance has led to forest loss or loss of regeneration capacity. In response, a case study was conducted to assess and demonstrate the potential of satellite remote sensing products for improving forest type maps and for assessing forest change over the last 25 years. Change detection products are needed for assessing risks for specific priority coastal forest types, such as live oak and baldcypress-dominated forest. Preliminary results indicate Landsat time series data are capable of generating the needed forest type and change detection products. Useful classifications were obtained using 2 strategies: 1) general forest classification based on use of 3 seasons of Landsat data from the same year; and 2) classification of specific forest types of concern using a single date of Landsat data in which a given targeted type is spectrally distinct compared to adjacent forested cover. When available, ASTER data was

  16. 36 CFR 261.6 - Timber and other forest products.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... of 1990 (16 U.S.C. 620, et seq.), or its implementing regulations at 36 CFR 223.185-223.203... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Timber and other forest products. 261.6 Section 261.6 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF...

  17. 36 CFR 261.6 - Timber and other forest products.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... of 1990 (16 U.S.C. 620, et seq.), or its implementing regulations at 36 CFR 223.185-223.203... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Timber and other forest products. 261.6 Section 261.6 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF...

  18. 36 CFR 261.6 - Timber and other forest products.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... of 1990 (16 U.S.C. 620, et seq.), or its implementing regulations at 36 CFR 223.185-223.203... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Timber and other forest products. 261.6 Section 261.6 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF...

  19. 36 CFR 261.6 - Timber and other forest products.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... of 1990 (16 U.S.C. 620, et seq.), or its implementing regulations at 36 CFR 223.185-223.203... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Timber and other forest products. 261.6 Section 261.6 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF...

  20. 36 CFR 261.6 - Timber and other forest products.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... of 1990 (16 U.S.C. 620, et seq.), or its implementing regulations at 36 CFR 223.185-223.203... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Timber and other forest products. 261.6 Section 261.6 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF...

  1. Integrated Forest Products Refinery (IFPR)

    SciTech Connect

    van Heiningen, Adriaan R. P.

    2010-05-29

    about 1% (on pulp). By using the wet-end retention aid guar gum during the adsorption process at a charge of 0.5% on pulp the yield gain may be increased to about 5%. Unfortunately, most of this yield increase is lost during subsequent alkaline treatments in the pulp bleach plant. It was found that by performing the adsorption at alkaline conditions the adsorption loss during alkaline treatment in the bleach plant is mostly avoided. Thus a permanent adsorption yield of about 3 and 1.5% (on pulp) was obtained with addition of guar gum at a charge of 0.5 and 0.1% respectively during adsorption of GL hardwood extract on pre-extracted kraft pulp at optimal conditions of pH 11.5, 90 C for 60 minutes at 5% consistency. The beatability of the adsorbed kraft pulps was improved. Also, significant physical strength improvements were achieved. Further study is needed to determine whether the improvements in pulp yield and paper properties make this an economic IFPR concept. Application of the wood solids of a hot water extract of Acer rubrum wood strands as a substitute for polystyrene used for production of SMC maintained the water adsorption properties of the final product. Further work on the physical properties of the hemicellulose containing SMCs need to be completed to determine the potential of wood extracts for the production of partially renewable SMCs. The discovery of the “near-neutral” green liquor extraction process for hardwood was formed the basis for a commercial Integrated Biorefinery that will extract hemicelluloses from wood chips to make biofuels and other specialty chemicals. The pulp production process will be maintained as is proposed in the present researched IFBR concept. This Integrated Biorefinery will be constructed by Red Shield Acquisition LLC (RSA) at the Old Town kraft pulp mill in Maine. RSA in collaboration with the University of Maine will develop and commercialize the hemicellulose extraction process, the conversion of the hemicellulose

  2. Extreme warm temperatures alter forest phenology and productivity in Europe.

    PubMed

    Crabbe, Richard A; Dash, Jadu; Rodriguez-Galiano, Victor F; Janous, Dalibor; Pavelka, Marian; Marek, Michal V

    2016-09-01

    Recent climate warming has shifted the timing of spring and autumn vegetation phenological events in the temperate and boreal forest ecosystems of Europe. In many areas spring phenological events start earlier and autumn events switch between earlier and later onset. Consequently, the length of growing season in mid and high latitudes of European forest is extended. However, the lagged effects (i.e. the impact of a warm spring or autumn on the subsequent phenological events) on vegetation phenology and productivity are less explored. In this study, we have (1) characterised extreme warm spring and extreme warm autumn events in Europe during 2003-2011, and (2) investigated if direct impact on forest phenology and productivity due to a specific warm event translated to a lagged effect in subsequent phenological events. We found that warmer events in spring occurred extensively in high latitude Europe producing a significant earlier onset of greening (OG) in broadleaf deciduous forest (BLDF) and mixed forest (MF). However, this earlier OG did not show any significant lagged effects on autumnal senescence. Needleleaf evergreen forest (NLEF), BLDF and MF showed a significantly delayed end of senescence (EOS) as a result of extreme warm autumn events; and in the following year's spring phenological events, OG started significantly earlier. Extreme warm spring events directly led to significant (p=0.0189) increases in the productivity of BLDF. In order to have a complete understanding of ecosystems response to warm temperature during key phenological events, particularly autumn events, the lagged effect on the next growing season should be considered. PMID:27152990

  3. 29 CFR 780.1015 - Other forest products.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... means any plant of the forest and includes, of course, deciduous plants as well. ... 29 Labor 3 2012-07-01 2012-07-01 false Other forest products. 780.1015 Section 780.1015 Labor... Provisions Under Section 13(d) Requirements for Exemption § 780.1015 Other forest products. The...

  4. 29 CFR 780.1015 - Other forest products.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... means any plant of the forest and includes, of course, deciduous plants as well. ... 29 Labor 3 2014-07-01 2014-07-01 false Other forest products. 780.1015 Section 780.1015 Labor... Provisions Under Section 13(d) Requirements for Exemption § 780.1015 Other forest products. The...

  5. 29 CFR 780.1015 - Other forest products.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... means any plant of the forest and includes, of course, deciduous plants as well. ... 29 Labor 3 2011-07-01 2011-07-01 false Other forest products. 780.1015 Section 780.1015 Labor... Provisions Under Section 13(d) Requirements for Exemption § 780.1015 Other forest products. The...

  6. 29 CFR 780.1015 - Other forest products.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... means any plant of the forest and includes, of course, deciduous plants as well. ... 29 Labor 3 2010-07-01 2010-07-01 false Other forest products. 780.1015 Section 780.1015 Labor... Provisions Under Section 13(d) Requirements for Exemption § 780.1015 Other forest products. The...

  7. 29 CFR 780.1015 - Other forest products.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... means any plant of the forest and includes, of course, deciduous plants as well. ... 29 Labor 3 2013-07-01 2013-07-01 false Other forest products. 780.1015 Section 780.1015 Labor... Provisions Under Section 13(d) Requirements for Exemption § 780.1015 Other forest products. The...

  8. 75 FR 64617 - National Forest Products Week, 2010

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-20

    ... Independence of the United States of America the two hundred and thirty-fifth. (Presidential Sig.) [FR Doc... Documents#0;#0; ] Proclamation 8587 of October 15, 2010 National Forest Products Week, 2010 By the President... anniversary of National Forest Products Week, we recognize the enduring value of forests as...

  9. 25 CFR 163.14 - Sale of forest products.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Sale of forest products. 163.14 Section 163.14 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.14 Sale of forest products. (a) Consistent with the economic objectives...

  10. 25 CFR 163.14 - Sale of forest products.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Sale of forest products. 163.14 Section 163.14 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.14 Sale of forest products. (a) Consistent with the economic objectives...

  11. 25 CFR 163.26 - Forest product harvesting permits.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Forest product harvesting permits. 163.26 Section 163.26 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.26 Forest product harvesting permits. (a) Except as provided...

  12. 25 CFR 163.22 - Payment for forest products.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Payment for forest products. 163.22 Section 163.22 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.22 Payment for forest products. (a) The basis of...

  13. 25 CFR 163.14 - Sale of forest products.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Sale of forest products. 163.14 Section 163.14 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.14 Sale of forest products. (a) Consistent with the economic objectives...

  14. 25 CFR 163.22 - Payment for forest products.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Payment for forest products. 163.22 Section 163.22 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.22 Payment for forest products. (a) The basis of...

  15. 25 CFR 163.16 - Forest product sales without advertisement.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Forest product sales without advertisement. 163.16 Section 163.16 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.16 Forest product sales without...

  16. 25 CFR 163.14 - Sale of forest products.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Sale of forest products. 163.14 Section 163.14 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.14 Sale of forest products. (a) Consistent with the economic objectives...

  17. 25 CFR 163.22 - Payment for forest products.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Payment for forest products. 163.22 Section 163.22 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.22 Payment for forest products. (a) The basis of volume determination...

  18. 25 CFR 163.26 - Forest product harvesting permits.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Forest product harvesting permits. 163.26 Section 163.26 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.26 Forest product harvesting permits. (a) Except as provided...

  19. 25 CFR 163.14 - Sale of forest products.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Sale of forest products. 163.14 Section 163.14 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.14 Sale of forest products. (a) Consistent with the economic objectives...

  20. 25 CFR 163.22 - Payment for forest products.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Payment for forest products. 163.22 Section 163.22 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.22 Payment for forest products. (a) The basis of...

  1. 25 CFR 163.26 - Forest product harvesting permits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Forest product harvesting permits. 163.26 Section 163.26 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.26 Forest product harvesting permits. (a) Except as provided...

  2. 25 CFR 163.22 - Payment for forest products.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Payment for forest products. 163.22 Section 163.22 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.22 Payment for forest products. (a) The basis of...

  3. 25 CFR 163.26 - Forest product harvesting permits.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Forest product harvesting permits. 163.26 Section 163.26 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.26 Forest product harvesting permits. (a) Except as provided...

  4. 25 CFR 163.26 - Forest product harvesting permits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Forest product harvesting permits. 163.26 Section 163.26 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.26 Forest product harvesting permits. (a) Except as provided...

  5. 25 CFR 163.16 - Forest product sales without advertisement.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Forest product sales without advertisement. 163.16 Section 163.16 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.16 Forest product sales without advertisement. (a) Sales...

  6. 25 CFR 163.16 - Forest product sales without advertisement.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Forest product sales without advertisement. 163.16 Section 163.16 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.16 Forest product sales without...

  7. 25 CFR 163.16 - Forest product sales without advertisement.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Forest product sales without advertisement. 163.16 Section 163.16 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.16 Forest product sales without...

  8. 25 CFR 163.16 - Forest product sales without advertisement.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Forest product sales without advertisement. 163.16 Section 163.16 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.16 Forest product sales without...

  9. Key canopy traits drive forest productivity.

    PubMed

    Reich, Peter B

    2012-06-01

    Quantifying the mechanistic links between carbon fluxes and forest canopy attributes will advance understanding of leaf-to-ecosystem scaling and its potential application to assessing terrestrial ecosystem metabolism. Important advances have been made, but prior studies that related carbon fluxes to multiple canopy traits are scarce. Herein, presenting data for 128 cold temperate and boreal forests across a regional gradient of 600 km and 5.4°C (from 2.4°C to 7.8°C) in mean annual temperature, I show that stand-scale productivity is a function of the capacity to harvest light (represented by leaf area index, LAI), and to biochemically fix carbon (represented by canopy nitrogen concentration, %N). In combination, LAI and canopy %N explain greater than 75 per cent of variation in above-ground net primary productivity among forests, expressed per year or per day of growing season. After accounting for growing season length and climate effects, less than 10 per cent of the variance remained unexplained. These results mirror similar relations of leaf-scale and canopy-scale (eddy covariance) maximum photosynthetic rates to LAI and %N. Collectively, these findings indicate that canopy structure and chemistry translate from instantaneous physiology to annual carbon fluxes. Given the increasing capacity to remotely sense canopy LAI, %N and phenology, these results support the idea that physiologically based scaling relations can be useful tools for global modelling. PMID:22279168

  10. Contrasting responses of forest ecosystems to rising atmospheric CO2: Implications for the global C cycle

    NASA Astrophysics Data System (ADS)

    Delucia, E. H.; Moore, D. J.; Norby, R. J.

    2005-09-01

    In two parallel but independent experiments, Free Air CO2 Enrichment (FACE) technology was used to expose plots within contrasting evergreen loblolly pine (Pinus taeda L.) and deciduous sweetgum (Liquidambar styraciflua L.) forests to the level of CO2 anticipated in 2050. Net primary production (NPP) and net ecosystem production (NEP) increased in both forests. In the year 2000, after exposing pine and sweetgum to elevated CO2 for approximately 5 and 3 years, a complete budget calculation revealed increases in net ecosystem production (NEP) of 41% and 44% in the pine forest and sweetgum forest, respectively, representing the storage of an additional 174 gC m-2 and 128 gC m-2 in these forests. The stimulation of NPP without corresponding increases in leaf area index or light absorption in either forest resulted in 23-27% stimulation in radiation-use efficiency, defined as NPP per unit absorbed photosynthetically active radiation. Greater plant respiration contributed to lower NPP in the loblolly pine forest than in the sweetgum forest, and these forests responded differently to CO2 enrichment. Where the pine forest added C primarily to long-lived woody tissues, exposure to elevated CO2 caused a large increase in the production of labile fine roots in the sweetgum forest. Greater allocation to more labile tissues may cause more rapid cycling of C back to the atmosphere in the sweetgum forest compared to the pine forest. Imbalances in the N cycle may reduce the response of these forests to experimental exposure to elevated CO2 in the future, but even at the current stimulation observed for these forests, the effect of changes in land use on C sequestration are likely to be larger than the effect of CO2-induced growth stimulation.

  11. Forest turnover rates follow global and regional patterns of productivity

    USGS Publications Warehouse

    Stephenson, N.L.; van Mantgem, P.J.

    2005-01-01

    Using a global database, we found that forest turnover rates (the average of tree mortality and recruitment rates) parallel broad-scale patterns of net primary productivity. First, forest turnover was higher in tropical than in temperate forests. Second, as recently demonstrated by others, Amazonian forest turnover was higher on fertile than infertile soils. Third, within temperate latitudes, turnover was highest in angiosperm forests, intermediate in mixed forests, and lowest in gymnosperm forests. Finally, within a single forest physiognomic type, turnover declined sharply with elevation (hence with temperature). These patterns of turnover in populations of trees are broadly similar to the patterns of turnover in populations of plant organs (leaves and roots) found in other studies. Our findings suggest a link between forest mass balance and the population dynamics of trees, and have implications for understanding and predicting the effects of environmental changes on forest structure and terrestrial carbon dynamics. ??2005 Blackwell Publishing Ltd/CNRS.

  12. 78 FR 44523 - Burned Area Emergency Response, Forest Service

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-24

    ..., (78 FR 34031). This correction adds the Web site that was inadvertently omitted from the interim... Federal Register of June 6, 2013, in FR Doc. 2013-13459, on page 34031, column 3, after the first... Forest Service RIN 0596-AC73 Burned Area Emergency Response, Forest Service AGENCY: Forest Service,...

  13. 36 CFR 223.219 - Sustainable harvest of special forest products.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Sustainable harvest of special forest products. 223.219 Section 223.219 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST BOTANICAL PRODUCTS Special...

  14. 36 CFR 223.219 - Sustainable harvest of special forest products.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Sustainable harvest of special forest products. 223.219 Section 223.219 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST BOTANICAL PRODUCTS Special...

  15. 36 CFR 223.219 - Sustainable harvest of special forest products.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Sustainable harvest of special forest products. 223.219 Section 223.219 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST BOTANICAL PRODUCTS Special...

  16. 36 CFR 223.219 - Sustainable harvest of special forest products.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Sustainable harvest of special forest products. 223.219 Section 223.219 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST BOTANICAL PRODUCTS Special...

  17. Contribution of Near Real Time MODIS-Based Forest Disturbance Detection Products to a National Forest Threat Early Warning System

    NASA Astrophysics Data System (ADS)

    Spruce, J.; Hargrove, W. W.; Gasser, J.; Smoot, J.; Kuper, P.

    2011-12-01

    maintained by the National Environmental Modeling and Analysis Center. The FCAV EWS has been used to aid multiple Federal and State agency forest management activities, including aerial disturbance detection surveys, as well as rapid response preliminary assessments of timber loss due to tornadoes, regional drought studies, and fire damage assessments. The FCAV allows end-users to assess the context of apparent forest vegetation change with respect to ancillary data, such as land cover, topography, hydrology, climate variables, and administrative boundaries. Such change products are being evaluated through case studies involving comparison with higher spatial resolution satellite, aerial, and field data. The presentation will include multiple examples in which regionally evident forest disturbances were successfully detected and monitored with the MODIS-based change products, as part of the FCAV. FCAV's MODIS forest change products enable end-users (e.g., resource managers) to view and monitor forest hazards at regional scales throughout the year and across the nation.

  18. Comparison of growth response to thinning in oak forests managed as coppice with standards and high forest

    NASA Astrophysics Data System (ADS)

    Gautam, S.; Hasenauer, H.; Pietsch, S. A.

    2009-04-01

    The BIOME-BGC model integrates the main physical, biological and physiological processes based on current understanding of ecophysiology to assess forest ecosystem dynamics. This study evaluates the application of the model to assess the thinning effects on coppiced oak forests in Austria. We analyze the growth response, i.e. growth efficiency (GE), nitrogen use efficiency (NUE), water use efficiency (WUE) and radiation use efficiency (RUE) of oak forests to thinning. The results of coppice with standards and high forests simulations are analysed for differences in simulated growth response after thinning. The forest field data of the year 2006 and the respective model runs are used to evaluate model application. Strong positive relationship (r2 = 0.90) with unbiased results and statistically insignificant differences between predicted and observed volume allows the use of the model as a diagnostic tool to assess management effects. Results indicate that the coppice with standards exhibits a significantly higher yield by 2.97% (i.e. 10 cubic meters per hectare in one rotation), a higher harvest (49.9%) but a lower growing stock (19.69%) than the high forests. The higher growing stock and the lower extraction in the high forests confirm that the high forest sequestrates significantly more carbon than the coppice with standards. Results show that thinning leads to an increase in the GE, the NUE and the WUE, and to a decrease in the RUE. Although the coppice with standards forest ecosystem exhibits higher values in all studied growth parameters, only the difference in the NUE was statistically significant. This verifies that the difference in the yield between the coppice with standards and the high forests is mainly governed by the NUE difference in stands after thinning. The coppice with standards system produces an equal amount of net primary production while consuming significantly less nitrogen (16%) compared to the high forest system. In the coppice with

  19. Forest Products Industry of the Future

    SciTech Connect

    Los Alamos Technical Associates, Inc

    2002-05-01

    Los Alamos Technical Associates, Inc (LATA) conducted an evaluation of the potential impact and value of a portion of the current portfolio of r&d projects supported by the Office of Industrial Technology and the Forest Products Industry of the Future. The mission of the evaluation was to (a) assess the potential impact of the projects to meet the critical goals of the industry as identified in the vision and roadmapping documents. (b) Evaluate the relationship between the current portfolio of projects and the Agenda 202 Implementation Plan. In addition, evaluate the relationship between the portfolio and the newly revised draft technology strategy being created by the industry. (c) Identify areas where current efforts are making significant progress towards meeting industry goals and identify areas where additional work my be required to meet these goals. (d) Make recommendations to the DOE and the Forest Products Industry on possible improvements in the portfolio and in the current methodology that DOE uses to assess potential impacts on its R&D activities.

  20. Soil production in forested landscapes (Invited)

    NASA Astrophysics Data System (ADS)

    Roering, J. J.; Booth, A. M.

    2009-12-01

    One of the most fundamental characteristics that defines landscapes is the presence or absence of a soil mantle. In actively eroding terrain, soil (and other natural resources that depend on it) persists only when the rate of soil production is not eclipsed by denudation. Despite successful efforts to empirically estimate long-term rates of soil production, little predictive capability exists as soil formation results from a complex interplay of biological, physical, and chemical processes. Here, we synthesize a suite of observations from the steep, forested Oregon Coast Range (OCR) and anlayze the role of trees in the conversion of bedrock to soil. Pit/mound topography on forest floors attests to the persistent, wholesale overturning of soil by tree root activity. Using airborne LiDAR data for our study site in the western Oregon Coast Range, we calculated how terrain roughness varies with spatial scale. At scales greater than 10m, the well-established ridge/valley structure of the landscape defines the topography; whereas for scales less than 7m, terrain roughness increases rapidly reflecting the stochastic nature of bioturbation associated with large, coniferous trees. Empirical estimates of soil production in the OCR by Heimsath et al (2001, ESPL) reveal that production rates decrease exponentially with depth and the decay constant is 2.68 (1/m). From dozens of soil pits in the OCR, we show that the density of trees roots declines exponentially with depth at a similar rate, 2.57 (1/m). In other words, rates of soil production appear to be well-correlated with root density. Bedrock is often excavated during tree turnover events and we documented that the volume of bedrock incorporated in overturned coniferous rootwads increases rapidly for tree diameters greater than 0.5m (which correponds to a 60-80 yr old Douglas fir tree in Western Oregon). Smaller (and thus younger) trees entrain negligible bedrock when overturned, suggesting that their root systems are

  1. Contribution of Near Real Time MODIS-Based Forest Disturbance Detection Products to a National Forest Threat Early Warning System

    NASA Technical Reports Server (NTRS)

    Spruce, Joseph P.; Hargrove, William; Glasser, Jerry; Kuper, Philip D.

    2011-01-01

    FCAV EWS has been used to aid multiple Federal and State agency forest management activities, including aerial disturbance detection surveys, as well as rapid response preliminary assessments of timber loss due to tornadoes, regional drought studies, and fire damage assessments. The FCAV allows end-users to assess the context of apparent forest vegetation change with respect to ancillary data, such as land cover, topography, hydrology, climate variables, and administrative boundaries. Such change products are being evaluated through case studies involving comparison with higher spatial resolution satellite, aerial, and field data. The presentation will include multiple examples in which regionally evident forest disturbances were successfully detected and monitored with the MODIS-based change products, as part of the FCAV. FCAV's MODIS forest change products enable end-users (e.g., resource managers) to monitor forest hazards at regional scales throughout the year and across the nation.

  2. Changes in Soil Nitrogen Storage and Dynamics in Response to Forest Management in Southeastern Pine Forest

    NASA Astrophysics Data System (ADS)

    Boutton, T. W.; Foote, J. A.; Scott, D. A.

    2013-12-01

    , root N varied significantly through time. Soil δ15N was significantly impacted by harvest intensity and time. Soil δ15N values were always lowest (1.21-1.96‰) in the bole only treatment, while those in the more intensely harvested treatments were higher (1.41-2.72‰). Higher soil δ15N values suggest that N-losses following tree harvest were greater in the more intense harvest treatments, consistent with the smaller soil N pool sizes observed in those treatments. Neither soil compaction nor the harvest method x soil compaction interaction had an effect on any response variables. Results indicate that more severe forest harvest practices that maximized biomass and litter removal resulted in significant ecosystem N-losses that have not yet been replenished even 15 yrs following treatment. Since N is a limiting nutrient for tree growth in the sandy soils of the Gulf Coastal Plain, tree harvest practices that favor N-retention will help ensure the continuity of key ecosystem services and sustain the productivity of forestlands in this region.

  3. Forests of opportunities and mischief: disentangling the interactions between forests, parasites and immune responses.

    PubMed

    Renner, Swen C; Lüdtke, Bruntje; Kaiser, Sonja; Kienle, Julia; Schaefer, H Martin; Segelbacher, Gernot; Tschapka, Marco; Santiago-Alarcon, Diego

    2016-08-01

    Habitat characteristics determine the presence of individuals through resource availability, but at the same time, such features also influence the occurrence of parasites. We analyzed how birds respond to changes in interior forest structures, to forest management regimes, and to the risk of haemosporidian infections. We captured and took blood samples from blackcaps (Sylvia atricapilla) and chaffinches (Fringilla coelebs) in three different forest types (beech, mixed deciduous, spruce). We measured birds' body asymmetries, detected avian haemosporidians, and counted white blood cells as an immune measure of each individual per forest type. We used, to our knowledge for the first time, continuous forest structural parameters to quantify habitat structure, and found significant effects of habitat structure on parasite prevalence that previously have been undetected. We found three times higher prevalence for blackcaps compared with chaffinches. Parasite intensity varied significantly within host species depending on forest type, being lowest in beech forests for both host species. Structurally complex habitats with a high degree of entropy had a positive effect on the likelihood of acquiring an infection, but the effect on prevalence was negative for forest sections with a south facing aspect. For blackcaps, forest gaps also had a positive effect on prevalence, but canopy height had a negative one. Our results suggest that forest types and variations in forest structure influence the likelihood of acquiring an infection, which subsequently has an influence on host health status and body condition; however, responses to some environmental factors are host-specific. PMID:27247106

  4. Improving Post-Hurricane Katrina Forest Management with MODIS Time Series Products

    NASA Technical Reports Server (NTRS)

    Lewis, Mark David; Spruce, Joseph; Evans, David; Anderson, Daniel

    2012-01-01

    Hurricane damage to forests can be severe, causing millions of dollars of timber damage and loss. To help mitigate loss, state agencies require information on location, intensity, and extent of damaged forests. NASA's MODerate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) time series data products offers a potential means for state agencies to monitor hurricane-induced forest damage and recovery across a broad region. In response, a project was conducted to produce and assess 250 meter forest disturbance and recovery maps for areas in southern Mississippi impacted by Hurricane Katrina. The products and capabilities from the project were compiled to aid work of the Mississippi Institute for Forest Inventory (MIFI). A series of NDVI change detection products were computed to assess hurricane induced damage and recovery. Hurricane-induced forest damage maps were derived by computing percent change between MODIS MOD13 16-day composited NDVI pre-hurricane "baseline" products (2003 and 2004) and post-hurricane NDVI products (2005). Recovery products were then computed in which post storm 2006, 2007, 2008 and 2009 NDVI data was each singularly compared to the historical baseline NDVI. All percent NDVI change considered the 16-day composite period of August 29 to September 13 for each year in the study. This provided percent change in the maximum NDVI for the 2 week period just after the hurricane event and for each subsequent anniversary through 2009, resulting in forest disturbance products for 2005 and recovery products for the following 4 years. These disturbance and recovery products were produced for the Mississippi Institute for Forest Inventory's (MIFI) Southeast Inventory District and also for the entire hurricane impact zone. MIFI forest inventory products were used as ground truth information for the project. Each NDVI percent change product was classified into 6 categories of forest disturbance intensity. Stand age

  5. Forest Fruit Production Is Higher on Sumatra Than on Borneo

    PubMed Central

    Wich, Serge A.; Vogel, Erin R.; Larsen, Michael D.; Fredriksson, Gabriella; Leighton, Mark; Yeager, Carey P.; Brearley, Francis Q.; van Schaik, Carel P.; Marshall, Andrew J.

    2011-01-01

    Background Various studies have shown that the population densities of a number of forest vertebrates, such as orangutans, are higher on Sumatra than Borneo, and that several species exhibit smaller body sizes on Borneo than Sumatra and mainland Southeast Asia. It has been suggested that differences in forest fruit productivity between the islands can explain these patterns. Here we present a large-scale comparison of forest fruit production between the islands to test this hypothesis. Methodology/Principal Findings Data on fruit production were collated from Sumatran and Bornean sites. At six sites we assessed fruit production in three forest types: riverine, peat swamp and dryland forests. We compared fruit production using time-series models during different periods of overall fruit production and in different tree size classes. We examined overall island differences and differences specifically for fruiting period and tree size class. The results of these analyses indicate that overall the Sumatran forests are more productive than those on Borneo. This difference remains when each of the three forest types (dryland, riverine, and peat) are examined separately. The difference also holds over most tree sizes and fruiting periods. Conclusions/Significance Our results provide strong support for the hypothesis that forest fruit productivity is higher on Sumatra than Borneo. This difference is most likely the result of the overall younger and more volcanic soils on Sumatra than Borneo. These results contribute to our understanding of the determinants of faunal density and the evolution of body size on both islands. PMID:21738627

  6. 43 CFR 9265.4 - Sales of forest products, general.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Sales of forest products, general. 9265.4 Section 9265.4 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND... Vegetative Resources Management § 9265.4 Sales of forest products, general. Commission of any of the...

  7. 43 CFR 9265.4 - Sales of forest products, general.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Sales of forest products, general. 9265.4 Section 9265.4 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND... Vegetative Resources Management § 9265.4 Sales of forest products, general. Commission of any of the...

  8. 43 CFR 9265.4 - Sales of forest products, general.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Sales of forest products, general. 9265.4 Section 9265.4 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND... Vegetative Resources Management § 9265.4 Sales of forest products, general. Commission of any of the...

  9. 43 CFR 9265.4 - Sales of forest products, general.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Sales of forest products, general. 9265.4 Section 9265.4 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND... Vegetative Resources Management § 9265.4 Sales of forest products, general. Commission of any of the...

  10. Forestry/Forest Products. Subject Matter Update 1986-87.

    ERIC Educational Resources Information Center

    Oregon State Dept. of Education, Salem. Div. of Vocational Education.

    This publication recognizes the constantly changing requirements of the forestry/forest products industry and varying conditions for employment opportunities. It addresses the goal of relevance in education by enabling the educator to make timely adjustments in the subject matter of the forestry/forest products curriculum. There are six sections…

  11. 78 FR 62957 - National Forest Products Week, 2013

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-23

    ... thirty- eighth. (Presidential Sig.) [FR Doc. 2013-24990 Filed 10-22-13; 8:45 am] Billing code 3295-F4 ... Documents#0;#0; ] Proclamation 9044 of October 18, 2013 National Forest Products Week, 2013 By the President... recreation for workers and families across our country. During National Forest Products Week, we...

  12. 76 FR 65097 - National Forest Products Week, 2011

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-20

    ... thirty-sixth. (Presidential Sig.) [FR Doc. 2011-27319 Filed 10-19-11; 8:45 am] Billing code 3295-F2-P ... Documents#0;#0; ] Proclamation 8738 of October 14, 2011 National Forest Products Week, 2011 By the President... important part of our economy. During National Forest Products Week, we celebrate the value of our...

  13. FOREST RESPONSE PROGRAM: NATIONAL RESEARCH ON FOREST DECLINE AND AIR POLLUTION

    EPA Science Inventory

    The Forest Response Program (FRP) is a major research undertaking. t is fortunate to have the support of many of the nation's top scientists. he involvement of the Forest Service, the Environmental Protection Agency, and the broader scientific community gives the program a unique...

  14. Seasonal and multi-year ecohydrologic responses to forest thinning

    NASA Astrophysics Data System (ADS)

    Tague, C.; Dugger, A. L.; Moritz, M.

    2014-12-01

    In the water-limited forested watersheds of the Western US, a critical eco-hydrology question is how does thinning influence streamflow and water-stress for remaining vegetation. We summarize recent literature on field-based examples of analyses which show both increases and decreases in streamflow following moderate thinning either through drought-related mortality or forest management. We use RHESSys, a coupled eco-hydrologic model, to disentangle the controls that may influence thinning responses. We examine both within watershed (topography, water holding capacity) and between watersheds differences in climate and their influence on thinning effects. We use the model to develop probability distributions of streamflow and productivity responses across inter-annual variation in meteorology forcing in the year following thinning. We also look at longer-term, multi-year response to examine potential impact of thinning on subsequent drought vulnerability and mortality risk. A somewhat surprising result from this analysis is that there are scenarios where thinning can actually increase subsequent vulnerability of water resources to drought stress.

  15. Are Tropical Forest Responses to Rising Atmospheric CO2 Nutrient-Limited?

    NASA Astrophysics Data System (ADS)

    Santiago, L. S.; Wright, S. J.; Turner, B. L.

    2013-12-01

    Tropical forests are responsible for a large proportion of terrestrial gross primary production and are thought to be especially sensitive to climate change, suggesting that their responses and subsequent feedbacks to the global climate system are likely to be large. However, a critical gap in our knowledge is the extent to which nutrients limit the ability of tropical forest vegetation to increase carbon gain from increasing atmospheric CO2 (the concentration-carbon feedback). We present data from the only long-term nutrient addition experiment in a lowland tropical forest to anticipate tropical forest responses to changes in climate and atmospheric chemistry and the corresponding vegetation feedback to climate. We investigated the consequences of nitrogen, phosphorus and potassium limitation of forest productivity, microbial biomass and tree growth, in a full factorial fertilization experiment at the Barro Colorado Nature Monument in Panama. The 16 years of nutrient addition at have taught us important lessons regarding the function of tropical forest. We now know that fine root biomass decreases by up to 50% with K addition. We have also learned that tree growth is most enhanced by N and K addition, and that litterfall and microbial biomass were most enhanced by P addition. Different components of the ecosystem are limited by contrasting elements. Overall, the results demonstrate the potential for nutrients to limit the responses of tropical forests to rising atmospheric CO2.

  16. USE OF SEWAGE SLUDGE FOR FOREST-TREE SEEDLING PRODUCTION

    EPA Science Inventory

    Research was undertaken to determine the beneficial and harmful effects of using dewatered, digested sewage sludge in: (1) containerized production of forest tree seedlings, (2) tree seedling production in a conventional outdoor nursery, (3) establishment and growth of transplant...

  17. RESPONSE OF FOREST TREES TO SULFUR, NITROGEN, AND ASSOCIATED POLLUTANTS

    EPA Science Inventory

    The National Acid Precipitation Assessment Program created Forest Response Program (FRP) to assess the effects of acidic deposition on trees and forests in regions of the United States. esearch front the FRP and other programs is summarized in four Major Program Output documents ...

  18. Impacts of insect-related forest mortality on hydrologic partitioning and forest productivity in the Southern Rocky Mountains, USA

    NASA Astrophysics Data System (ADS)

    Molotch, N. P.

    2014-12-01

    Recent large-scale changes in forest cover over Western North America associated with insect-related forest mortality may have widespread impacts on water availability. These changes have potentially varied impacts on water availability as forest mortality influences rates of snow accumulation, snowmelt, and evapotranspiration. These changes may significantly alter runoff production and gross primary productivity in mountain forests. Analysis of remotely sensed vegetation greenness data indicate strong forest and understory growth dependencies associated with snow accumulation and snowmelt with peak snow water equivalent explaining 40-50% of inter-annual greenness variability in the Rocky Mountains. Examples of these dependencies will be presented based on the 2012 drought in the Southwestern US whereby near record low snow accumulation and record high potential evapotranspiration have resulted in record low forest greening as evident in the 30+ year satellite record. Forest response to aridity in 2012 was exacerbated by forest disturbance with greenness anomalies 90% greater in magnitude in Bark Beetle and Spruce Budworm affected areas versus undisturbed areas and 182% greater in magnitude in areas impacted by fire. Growing season length was inversely proportional to peak greenness with record high Normalized Difference Vegetation Index (NDVI) values in April (14% above average) corresponding with record low NDVI values in July (7% below average). Gross primary productivity (GPP) estimates from the Moderate Resolution Imaging Spectroradiometer (MODIS) and from the Niwot Ridge, Colorado Ameriflux tower indicate record high April GPP (30% and 90% above average for MODIS and the tower, respectively) correspodning with record low July GPP (19% and 30% below average, respectively). Differences in these energy, water, ecosystem relationships among difference distrurbance regimes indicate that the sensitivity of ecosystems to changes in climate is heavily dependent on

  19. 36 CFR 223.217 - Authority to dispose of special forest products.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Authority to dispose of special forest products. 223.217 Section 223.217 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER Special Forest Products §...

  20. 36 CFR 223.217 - Authority to dispose of special forest products.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Authority to dispose of special forest products. 223.217 Section 223.217 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS,...

  1. 36 CFR 223.217 - Authority to dispose of special forest products.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Authority to dispose of special forest products. 223.217 Section 223.217 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS,...

  2. 36 CFR 223.217 - Authority to dispose of special forest products.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Authority to dispose of special forest products. 223.217 Section 223.217 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS,...

  3. 36 CFR 223.217 - Authority to dispose of special forest products.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Authority to dispose of special forest products. 223.217 Section 223.217 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS,...

  4. 36 CFR 223.219 - Sustainable harvest of special forest products.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Sustainable harvest of special forest products. 223.219 Section 223.219 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER Special Forest Products § 223.219 Sustainable harvest of special...

  5. Factors affecting the remotely sensed response of coniferous forest plantations

    SciTech Connect

    Danson, F.M. ); Curran, P.J. )

    1993-01-01

    Remote sensing of forest biophysical properties has concentrated upon forest sites with a wide range of green vegetation amount and thereby leaf area index and canopy cover. However, coniferous forest plantations, an important forest type in Europe, are managed to maintain a large amount of green vegetation with little spatial variation. Therefore, the strength of the remotely sensed signal will, it is hypothesized, be determined more by the structure of this forest than by its cover. Airborne Thematic Mapper (ATM) and SPOT-1 HRV data were used to determine the effects of this structural variation on the remotely sensed response of a coniferous forest plantation in the United Kingdom. Red and near infrared radiance were strongly and negatively correlated with a range of structural properties and with the age of the stands but weakly correlated with canopy cover. A composite variable, related to the volume of the canopy, accounted for over 75% of the variation in near infrared radiance. A simple model that related forest structural variables to the remotely sensed response was used to understand and explain this response from a coniferous forest plantation.

  6. Forest stand structure, productivity, and age mediate climatic effects on aspen decline.

    PubMed

    Bell, David M; Bradford, John B; Lauenroth, William K

    2014-08-01

    Because forest stand structure, age, and productivity can mediate the impacts of climate on quaking aspen (Populus tremuloides) mortality, ignoring stand-scale factors limits inference on the drivers of recent sudden aspen decline. Using the proportion of aspen trees that were dead as an index of recent mortality at 841 forest inventory plots, we examined the relationship of this mortality index to forest structure and climate in the Rocky Mountains and Intermountain Western United States. We found that forest structure explained most of the patterns in mortality indices, but that variation in growing-season vapor pressure deficit and winter precipitation over the last 20 years was important. Mortality index sensitivity to precipitation was highest in forests where aspen exhibited high densities, relative basal areas, quadratic mean diameters, and productivities, whereas sensitivity to vapor pressure deficit was highest in young forest stands. These results indicate that the effects of drought on mortality may be mediated by forest stand development, competition with encroaching conifers, and physiological vulnerabilities of large trees to drought. By examining mortality index responses to both forest structure and climate, we show that forest succession cannot be ignored in studies attempting to understand the causes and consequences of sudden aspen decline. PMID:25230455

  7. Forest stand structure, productivity, and age mediate climatic effects on aspen decline

    USGS Publications Warehouse

    Bell, David M.; Bradford, John B.; Lauenroth, William K.

    2014-01-01

    Because forest stand structure, age, and productivity can mediate the impacts of climate on quaking aspen (Populus tremuloides) mortality, ignoring stand-scale factors limits inference on the drivers of recent sudden aspen decline. Using the proportion of aspen trees that were dead as an index of recent mortality at 841 forest inventory plots, we examined the relationship of this mortality index to forest structure and climate in the Rocky Mountains and Intermountain Western United States. We found that forest structure explained most of the patterns in mortality indices, but that variation in growing-season vapor pressure deficit and winter precipitation over the last 20 years was important. Mortality index sensitivity to precipitation was highest in forests where aspen exhibited high densities, relative basal areas, quadratic mean diameters, and productivities, whereas sensitivity to vapor pressure deficit was highest in young forest stands. These results indicate that the effects of drought on mortality may be mediated by forest stand development, competition with encroaching conifers, and physiological vulnerabilities of large trees to drought. By examining mortality index responses to both forest structure and climate, we show that forest succession cannot be ignored in studies attempting to understand the causes and consequences of sudden aspen decline.

  8. Responses of Isolated Wetland Herpetofauna to Upland Forest Management

    SciTech Connect

    Russell, K.R.; Hanlin, H.G.; Wigley, T.B.; Guynn, D.C., Jr.

    2002-01-02

    Measurement of responses of herpetofauna at isolated wetlands in the Coastal Plain of South Carolina to disturbance of adjacent loblolly pine forest. Many species of isolated wetland herpetofauna in the Southeastern Coastal Plain may tolerate some disturbance in adjacent upland stands. Responses of isolated wetland herpetofauna to upland silviculture and the need for adjacent forested buffers likely depend on the specific landscape context in which the wetlands occur and composition of the resident herpetofaunal community.

  9. Forestry/Forest Products Cluster Brief. Vocational Education in Oregon.

    ERIC Educational Resources Information Center

    Brock, Howard

    This guide sets forth minimum approval criteria for vocational forestry/forest products training programs in Oregon. The curriculum emphasizes the basic skills of forest management, harvesting, and manufacturing. The information in the guide is intended for use by district-level curriculum planners, teachers, regional coordinators, or state…

  10. Regional carbon dioxide implications of forest bioenergy production

    NASA Astrophysics Data System (ADS)

    Hudiburg, Tara W.; Law, Beverly E.; Wirth, Christian; Luyssaert, Sebastiaan

    2011-11-01

    Strategies for reducing carbon dioxide emissions include substitution of fossil fuel with bioenergy from forests, where carbon emitted is expected to be recaptured in the growth of new biomass to achieve zero net emissions, and forest thinning to reduce wildfire emissions. Here, we use forest inventory data to show that fire prevention measures and large-scale bioenergy harvest in US West Coast forests lead to 2-14% (46-405TgC) higher emissions compared with current management practices over the next 20 years. We studied 80 forest types in 19 ecoregions, and found that the current carbon sink in 16 of these ecoregions is sufficiently strong that it cannot be matched or exceeded through substitution of fossil fuels by forest bioenergy. If the sink in these ecoregions weakens below its current level by 30-60gCm-2yr-1 owing to insect infestations, increased fire emissions or reduced primary production, management schemes including bioenergy production may succeed in jointly reducing fire risk and carbon emissions. In the remaining three ecoregions, immediate implementation of fire prevention and biofuel policies may yield net emission savings. Hence, forest policy should consider current forest carbon balance, local forest conditions and ecosystem sustainability in establishing how to decrease emissions.

  11. Scaling Stream Flow Response to Forest Disturbance: the SID Project

    NASA Astrophysics Data System (ADS)

    Buttle, J. M.; Beall, F. D.; Creed, I. F.; Gordon, A. M.; Mackereth, R.; McLaughlin, J. W.; Sibley, P. K.

    2004-05-01

    We do not have a good understanding of the hydrologic implications of forest harvesting in Ontario, either for current or alternative management approaches. Attempts to address these implications face a three-fold problem: data on hydrologic response to forest disturbance in Ontario are lacking; most studies of these responses have been in regions with forest cover and hydrologic conditions that differ from the Ontario context; and these studies have generally been conducted at relatively small scales (<1 km2). It is generally assumed that hydrologic changes induced by forest disturbance should diminish with increasing scale due to the buffering capacity of large drainage basins. Recent modeling exercises and reanalysis of paired-basin results call this widespread applicability of this assumption into question, with important implications for assessing the cumulative impacts of forest disturbance on basin stream flow. The SID (Scalable Indicators of Disturbance) project combines stream flow monitoring across basin scales with the RHESSys modeling framework to identify forest disturbance impacts on stream flow characteristics in Ontario's major forest ecozones. As a precursor to identifying stream flow response to forest disturbance, we are examining the relative control of basin geology, topography, typology and topology on stream flow characteristics under undisturbed conditions. This will assist in identifying the dominant hydrologic processes controlling basin stream flow that must be incorporated into the RHESSys model framework in order to emulate forest disturbance and its hydrologic impacts. We present preliminary results on stream flow characteristics in a low-relief boreal forest landscape, and explore how the dominant processes influencing these characteristics change with basin scale in this landscape under both reference and disturbance conditions.

  12. Information system of forest growth and productivity by site quality type and elements of forest

    NASA Astrophysics Data System (ADS)

    Khlyustov, V.

    2012-04-01

    Information system of forest growth and productivity by site quality type and elements of forest V.K. Khlustov Head of the Forestry Department of Russian State Agrarian University named after K.A.Timiryazev doctor of agricultural sciences, professor The efficiency of forest management can be improved substantially by development and introduction of principally new models of forest growth and productivity dynamics based on regionalized site specific parameters. Therefore an innovative information system was developed. It describes the current state and gives a forecast for forest stand parameters: growth, structure, commercial and biological productivity depend on type of site quality. In contrast to existing yield tables, the new system has environmental basis: site quality type. The information system contains set of multivariate statistical models and can work at the level of individual trees or at the stand level. The system provides a graphical visualization, as well as export of the emulation results. The System is able to calculate detailed description of any forest stand based on five initial indicators: site quality type, site index, stocking, composition, and tree age by elements of the forest. The results of the model run are following parameters: average diameter and height, top height, number of trees, basal area, growing stock (total, commercial with distribution by size, firewood and residuals), live biomass (stem, bark, branches, foliage). The system also provides the distribution of mentioned above forest stand parameters by tree diameter classes. To predict the future forest stand dynamics the system require in addition the time slot only. Full set of forest parameters mention above will be provided by the System. The most conservative initial parameters (site quality type and site index) can be kept in the form of geo referenced polygons. In this case the system would need only 3 dynamic initial parameters (stocking, composition and age) to

  13. A Bayesian Belief Network approach to assess the potential of non wood forest products for small scale forest owners

    NASA Astrophysics Data System (ADS)

    Vacik, Harald; Huber, Patrick; Hujala, Teppo; Kurtilla, Mikko; Wolfslehner, Bernhard

    2015-04-01

    It is an integral element of the European understanding of sustainable forest management to foster the design and marketing of forest products, non-wood forest products (NWFPs) and services that go beyond the production of timber. Despite the relevance of NWFPs in Europe, forest management and planning methods have been traditionally tailored towards wood and wood products, because most forest management models and silviculture techniques were developed to ensure a sustained production of timber. Although several approaches exist which explicitly consider NWFPs as management objectives in forest planning, specific models are needed for the assessment of their production potential in different environmental contexts and for different management regimes. Empirical data supporting a comprehensive assessment of the potential of NWFPs are rare, thus making development of statistical models particularly problematic. However, the complex causal relationships between the sustained production of NWFPs, the available ecological resources, as well as the organizational and the market potential of forest management regimes are well suited for knowledge-based expert models. Bayesian belief networks (BBNs) are a kind of probabilistic graphical model that have become very popular to practitioners and scientists mainly due to the powerful probability theory involved, which makes BBNs suitable to deal with a wide range of environmental problems. In this contribution we present the development of a Bayesian belief network to assess the potential of NWFPs for small scale forest owners. A three stage iterative process with stakeholder and expert participation was used to develop the Bayesian Network within the frame of the StarTree Project. The group of participants varied in the stages of the modelling process. A core team, consisting of one technical expert and two domain experts was responsible for the entire modelling process as well as for the first prototype of the network

  14. The effect of alder forest cover and alder forest conversion on site fertility and productivity

    SciTech Connect

    Van Miegroet, H.; Cole, D.W.; Homann, P.S.

    1988-01-01

    Red alder (Alnus rubra Bong.) is known for its ability to improve the status of soil N through symbiotic N fixation. The objective of this paper is to assess the effect of red alder forests and their removal on soil and solution chemistry and on the growth of trees subsequently established on such sites. This was achieved through a series of paired field comparisons at two locations in Washington, involving similar-aged pure alder and Douglas-fir forests on soils that were essentially the same prior to stand establishment. At Pack Forest alder and Douglas-fir stands on high- and low-productivity sites were subjected to three levels of harvesting: bore only removal, whole tree (aboveground) harvesting, and complete removal of all vegetation and forest floor. The effect of harvesting intensity was examined on nutrient removal with biomass and through leaching, and on subsequent seedling growth. At Thompson Research Center adjacent Douglas-fir and alder forests were harvested, and half of each area was replanted with either Douglas-fir or red alder seedlings, yielding four forest conversion units. Differences in growth patterns, tree nutrient status, and leaching losses between these conversion plots were examined. Compared with adjacent Douglas-fir forests, substantially more N, P, K, and Ca are tied up in aboveground vegetation and on the forest floor of alder forests, and these elements also cycle faster in alder ecosystems primarily due to the deciduous nature of alder.

  15. Monitoring Regional Forest Disturbances across the US with Near Real Time MODIS NDVI Products included in the ForWarn Forest Threat Early Warning System

    NASA Astrophysics Data System (ADS)

    Spruce, J.; Hargrove, W. W.; Gasser, J.; Norman, S. P.

    2013-12-01

    Forest threats across the US have become increasingly evident in recent years. These include regionally extensive disturbances (e.g., from drought, bark beetle outbreaks, and wildfires) that can occur across multiyear durations and result in extensive forest mortality. In addition, forests can be subject to ephemeral, sometimes yearly defoliation from various insects and types of storm damage. After prolonged severe disturbance, signs of forest recovery can vary in terms of satellite-based Normalized Difference Vegetation Index (NDVI) values. The increased extent and threat of forest disturbances in part led to the enactment of the 2003 Healthy Forest Restoration Act, which mandated that a national forest threat Early Warning System (EWS) be deployed. In response, the US Forest Service collaborated with NASA, DOE Oak Ridge National Laboratory, and the USGS Eros Data Center to build the near real time ForWarn forest threat EWS for monitoring regionally evident forest disturbances, starting on-line operations in 2010. Given the diversity of disturbance types, severities, and durations, ForWarn employs multiple historical baselines used with current NDVI to derive a suite of six nationwide 'weekly' forest change products. ForWarn uses daily 232 meter MODIS Aqua and Terra satellite NDVI data, including MOD13 products for deriving historical baseline NDVIs and eMODIS products for compiling current NDVI. Separately pre-processing the current and historical NDVIs, the Time Series Product Tool and the Phenological Parameters Estimation Tool are used to temporally reduce noise, fuse, and aggregate MODIS NDVIs into 24 day composites refreshed every 8 days with 46 dates of forest change products per year. The 24 day compositing interval typically enables new disturbances to be detected, while minimizing the frequency of residual atmospheric contamination. ForWarn's three standard forest change products compare current NDVI to that from the previous year, previous 3 years, and

  16. Estimating forest productivity with Thematic Mapper and biogeographical data

    NASA Technical Reports Server (NTRS)

    Cook, Elizabeth A.; Iverson, Louis R.; Graham, Robin L.

    1989-01-01

    Spectral data from the Landsat Thematic Mapper (TM) on three forest exosystems (the southern Illinois, the Great Smoky Mountains regions in Tennessee and North Carolina, and the central Adirondack Mountains in New York) were used in conjunction with ground-collected measures of forest productivity and such information as the area's slope, aspect, elevation, and soil and vegetation types, to develop models of regional forest productivity. It is shown that the models developed may be used to estimate the productivity of a region with a high degree of confidence, but that the reliability of single-pixel estimates is poor. The characteristics of a given ecosystem determine which spectral values are most closely related to forest productivity. Thus, mid-IR, NIR, and visible bands are most significant in Illinois and New York, while the thermal band is relatively more important in the Smokies.

  17. Modelling tropical forests response to logging

    NASA Astrophysics Data System (ADS)

    Cazzolla Gatti, Roberto; Di Paola, Arianna; Valentini, Riccardo; Paparella, Francesco

    2013-04-01

    Tropical rainforests are among the most threatened ecosystems by large-scale fragmentation due to human activity such as heavy logging and agricultural clearance. Although, they provide crucial ecosystem goods and services, such as sequestering carbon from the atmosphere, protecting watersheds and conserving biodiversity. In several countries forest resource extraction has experienced a shift from clearcutting to selective logging to maintain a significant forest cover and understock of living biomass. However the knowledge on the short and long-term effects of removing selected species in tropical rainforest are scarce and need to be further investigated. One of the main effects of selective logging on forest dynamics seems to be the local disturbance which involve the invasion of open space by weed, vines and climbers at the expense of the late-successional state cenosis. We present a simple deterministic model that describes the dynamics of tropical rainforest subject to selective logging to understand how and why weeds displace native species. We argue that the selective removal of tallest tropical trees carries out gaps of light that allow weeds, vines and climbers to prevail on native species, inhibiting the possibility of recovery of the original vegetation. Our results show that different regime shifts may occur depending on the type of forest management adopted. This hypothesis is supported by a dataset of trees height and weed/vines cover that we collected from 9 plots located in Central and West Africa both in untouched and managed areas.

  18. Conversion of Siberian Larch Forests in Response to Climate Change

    NASA Astrophysics Data System (ADS)

    Shuman, J. K.; Shugart, H. H.

    2009-12-01

    The Northern Hemisphere’s boreal forests and, in particular, the Siberian boreal forest zone, may have a particularly strong effect on the Earth’s climate through changes in the regional surface albedo. Warmer climate has been identified as a potential driver of the conversion of Siberia’s larch forests to dark-conifer forests of spruce and fir. This suggests a positive feedback cycle: warmer climate creates a succession from deciduous larch to dark-conifer forest; the resultant albedo change can then promote additional climate warming. The individual based forest growth model, FAREAST, which simulates the composition of the Russian forest, is used to test the impact of warming on forest succession and mitigation of this potential climate/cover feedback. Utilization of FAREAST with climate station and soil data from across Siberia generates baseline biomass (tCha-1) and species composition values from year zero to mature forest for current climate conditions. IPCC climate output data from two of NCAR’s Community Climate System Model 3.0 (CCSM) SRES climate change scenarios, which have stabilization at 720ppm of CO2 associated with 2.6°C warming and 550ppm CO2 with 1.2°C warming, are used to evaluate dominant species change in response to climate change. To explore mitigation of albedo changes associated with the predicted shift from larch to dark-conifer forest, the results for the current and two warming scenarios are compared to a set of model runs which introduce European Larch (Larix decidua). This deciduous species is adapted to warmer climate conditions and its introduction to Siberia could slow the rate of conversion to dark-conifer forests. Evaluation of climate as the driver for conversion of larch to dark-conifer enhances our ability to identify drivers of land surface change in this complex region and focus future analysis.

  19. Role of MODIS Vegetation Phenology Products in the U.S. for Warn Early Warning System for Forest Threats

    NASA Technical Reports Server (NTRS)

    Spruce, Joseph; Hargrove, William; Norman, Steve; Gasser, Gerald; Smoot, James; Kuper, Philip

    2012-01-01

    U.S. forests occupy approx 751 million acres (approx 1/3 of total land). Several abiotic and biotic damage agents disturb, damage, kill, and/or threaten these forests. Regionally extensive forest disturbances can also threaten human life and property, bio-diversity and water supplies. timely regional forest disturbance monitoring products are needed to aid forest health management work at finer scales. daily MODIS data provide a means to monitor regional forest disturbances on a weekly basis, leveraging vegetation phenology. In response, the USFS and NASA began collaborating in 2006 to develop a Near Real Time (NRT) forest monitoring capability, based on MODIS NDVI data, as part of a national forest threat Early Warning System (EWS).

  20. Forest floor community metatranscriptomes identify fungal and bacterial responses to N deposition in two maple forests

    PubMed Central

    Hesse, Cedar N.; Mueller, Rebecca C.; Vuyisich, Momchilo; Gallegos-Graves, La Verne; Gleasner, Cheryl D.; Zak, Donald R.; Kuske, Cheryl R.

    2015-01-01

    Anthropogenic N deposition alters patterns of C and N cycling in temperate forests, where forest floor litter decomposition is a key process mediated by a diverse community of bacteria and fungi. To track forest floor decomposer activity we generated metatranscriptomes that simultaneously surveyed the actively expressed bacterial and eukaryote genes in the forest floor, to compare the impact of N deposition on the decomposers in two natural maple forests in Michigan, USA, where replicate field plots had been amended with N for 16 years. Site and N amendment responses were compared using about 74,000 carbohydrate active enzyme transcript sequences (CAZymes) in each metatranscriptome. Parallel ribosomal RNA (rRNA) surveys of bacterial and fungal biomass and taxonomic composition showed no significant differences in either biomass or OTU richness between the two sites or in response to N. Site and N amendment were not significant variables defining bacterial taxonomic composition, but they were significant for fungal community composition, explaining 17 and 14% of the variability, respectively. The relative abundance of expressed bacterial and fungal CAZymes changed significantly with N amendment in one of the forests, and N-response trends were also identified in the second forest. Although the two ambient forests were similar in community biomass, taxonomic structure and active CAZyme profile, the shifts in active CAZyme profiles in response to N-amendment differed between the sites. One site responded with an over-expression of bacterial CAZymes, and the other site responded with an over-expression of both fungal and different bacterial CAZymes. Both sites showed reduced representation of fungal lignocellulose degrading enzymes in N-amendment plots. The metatranscriptome approach provided a holistic assessment of eukaryote and bacterial gene expression and is applicable to other systems where eukaryotes and bacteria interact. PMID:25954263

  1. Forest floor community metatranscriptomes identify fungal and bacterial responses to N deposition in two maple forests

    SciTech Connect

    Hesse, Cedar N.; Mueller, Rebecca C.; Vuyisich, Momchilo; Gallegos-Graves, La Verne; Gleasner, Cheryl D.; Zak, Donald R.; Kuske, Cheryl R.

    2015-04-23

    Anthropogenic N deposition alters patterns of C and N cycling in temperate forests, where forest floor litter decomposition is a key process mediated by a diverse community of bacteria and fungi. To track forest floor decomposer activity we generated metatranscriptomes that simultaneously surveyed the actively expressed bacterial and eukaryote genes in the forest floor, to compare the impact of N deposition on the decomposers in two natural maple forests in Michigan, USA, where replicate field plots had been amended with N for 16 years. Site and N amendment responses were compared using about 74,000 carbohydrate active enzyme transcript sequences (CAZymes) in each metatranscriptome. Parallel ribosomal RNA (rRNA) surveys of bacterial and fungal biomass and taxonomic composition showed no significant differences in either biomass or OTU richness between the two sites or in response to N. Site and N amendment were not significant variables defining bacterial taxonomic composition, but they were significant for fungal community composition, explaining 17 and 14% of the variability, respectively. The relative abundance of expressed bacterial and fungal CAZymes changed significantly with N amendment in one of the forests, and N-response trends were also identified in the second forest. Although the two ambient forests were similar in community biomass, taxonomic structure and active CAZyme profile, the shifts in active CAZyme profiles in response to N-amendment differed between the sites. One site responded with an over-expression of bacterial CAZymes, and the other site responded with an over-expression of both fungal and different bacterial CAZymes. Both sites showed reduced representation of fungal lignocellulose degrading enzymes in N-amendment plots. The metatranscriptome approach provided a holistic assessment of eukaryote and bacterial gene expression and is applicable to other systems where eukaryotes and bacteria interact.

  2. Forest floor community metatranscriptomes identify fungal and bacterial responses to N deposition in two maple forests

    DOE PAGESBeta

    Hesse, Cedar N.; Mueller, Rebecca C.; Vuyisich, Momchilo; Gallegos-Graves, La Verne; Gleasner, Cheryl D.; Zak, Donald R.; Kuske, Cheryl R.

    2015-04-23

    Anthropogenic N deposition alters patterns of C and N cycling in temperate forests, where forest floor litter decomposition is a key process mediated by a diverse community of bacteria and fungi. To track forest floor decomposer activity we generated metatranscriptomes that simultaneously surveyed the actively expressed bacterial and eukaryote genes in the forest floor, to compare the impact of N deposition on the decomposers in two natural maple forests in Michigan, USA, where replicate field plots had been amended with N for 16 years. Site and N amendment responses were compared using about 74,000 carbohydrate active enzyme transcript sequences (CAZymes)more » in each metatranscriptome. Parallel ribosomal RNA (rRNA) surveys of bacterial and fungal biomass and taxonomic composition showed no significant differences in either biomass or OTU richness between the two sites or in response to N. Site and N amendment were not significant variables defining bacterial taxonomic composition, but they were significant for fungal community composition, explaining 17 and 14% of the variability, respectively. The relative abundance of expressed bacterial and fungal CAZymes changed significantly with N amendment in one of the forests, and N-response trends were also identified in the second forest. Although the two ambient forests were similar in community biomass, taxonomic structure and active CAZyme profile, the shifts in active CAZyme profiles in response to N-amendment differed between the sites. One site responded with an over-expression of bacterial CAZymes, and the other site responded with an over-expression of both fungal and different bacterial CAZymes. Both sites showed reduced representation of fungal lignocellulose degrading enzymes in N-amendment plots. The metatranscriptome approach provided a holistic assessment of eukaryote and bacterial gene expression and is applicable to other systems where eukaryotes and bacteria interact.« less

  3. Forest floor community metatranscriptomes identify fungal and bacterial responses to N deposition in two maple forests.

    PubMed

    Hesse, Cedar N; Mueller, Rebecca C; Vuyisich, Momchilo; Gallegos-Graves, La Verne; Gleasner, Cheryl D; Zak, Donald R; Kuske, Cheryl R

    2015-01-01

    Anthropogenic N deposition alters patterns of C and N cycling in temperate forests, where forest floor litter decomposition is a key process mediated by a diverse community of bacteria and fungi. To track forest floor decomposer activity we generated metatranscriptomes that simultaneously surveyed the actively expressed bacterial and eukaryote genes in the forest floor, to compare the impact of N deposition on the decomposers in two natural maple forests in Michigan, USA, where replicate field plots had been amended with N for 16 years. Site and N amendment responses were compared using about 74,000 carbohydrate active enzyme transcript sequences (CAZymes) in each metatranscriptome. Parallel ribosomal RNA (rRNA) surveys of bacterial and fungal biomass and taxonomic composition showed no significant differences in either biomass or OTU richness between the two sites or in response to N. Site and N amendment were not significant variables defining bacterial taxonomic composition, but they were significant for fungal community composition, explaining 17 and 14% of the variability, respectively. The relative abundance of expressed bacterial and fungal CAZymes changed significantly with N amendment in one of the forests, and N-response trends were also identified in the second forest. Although the two ambient forests were similar in community biomass, taxonomic structure and active CAZyme profile, the shifts in active CAZyme profiles in response to N-amendment differed between the sites. One site responded with an over-expression of bacterial CAZymes, and the other site responded with an over-expression of both fungal and different bacterial CAZymes. Both sites showed reduced representation of fungal lignocellulose degrading enzymes in N-amendment plots. The metatranscriptome approach provided a holistic assessment of eukaryote and bacterial gene expression and is applicable to other systems where eukaryotes and bacteria interact. PMID:25954263

  4. Historic Response of Forests to Disturbance; Hydrologic Implications (Invited)

    NASA Astrophysics Data System (ADS)

    Millar, C. I.

    2013-12-01

    Mountain hydrology is influenced by the composition, structure, and function of forests, which in turn are affected by patterns and types of disturbance, both ecological (insect, disease) and physical (fire, wind, avalanche/landslide, weather/climate). Paleo-historic data provide inferences about the natural roles of disturbance in governing forest condition at landscape scale (e.g., forest die-offs, widespread changes in composition, forest type, or structure), and offer insights for vegetation and hydrological management under conditions of current and future climate change. Millennial (Holocene), centennial, and decadal temporal scales are presented for analysis of forest responses in mountains of western North America. Examples focus on the long-term effects of short-term disturbance, beneficial effects of disturbance on forest health, importance of legacy (sequencing of events), pace of climate variability, topographic control on forest health, lag effects, and interactions of multiple stressors. Historic forest condition and hydrologic relations inferred through dendrochronological analysis are put into current context.

  5. Contrasting responses of forest ecosystems to rising atmospheric CO2: Implications for the global C cycle

    SciTech Connect

    Norby, Richard J; DeLucia, E. H.; Moore, D J

    2005-01-01

    In two parallel but independent experiments, Free Air CO2 Enrichment (FACE) technology was used to expose plots within contrasting evergreen loblolly pine (Pinus taeda L.) and deciduous sweetgum (Liquidambar styraciflua L.) forests to the level of CO2 anticipated in 2050. Net primary production (NPP) and net ecosystem production (NEP) increased in both forests. In the year 2000, after exposing pine and sweetgum to elevated CO2 for approximately 5 and 3 years, a complete budget calculation revealed increases in net ecosystem production (NEP) of 41% and 44% in the pine forest and sweetgum forest, respectively, representing the storage of an additional 174 gC m-2 and 128 gC m-2 in these forests. The stimulation of NPP without corresponding increases in leaf area index or light absorption in either forest resulted in 23-27% stimulation in radiation-use efficiency, defined as NPP per unit absorbed photosynthetically active radiation. Greater plant respiration contributed to lower NPP in the loblolly pine forest than in the sweetgum forest, and these forests responded differently to CO2 enrichment. Where the pine forest added C primarily to long-lived woody tissues, exposure to elevated CO2 caused a large increase in the production of labile fine roots in the sweetgum forest. Greater allocation to more labile tissues may cause more rapid cycling of C back to the atmosphere in the sweetgum forest compared to the pine forest. Imbalances in the N cycle may reduce the response of these forests to experimental exposure to elevated CO2 in the future, but even at the current stimulation observed for these forests, the effect of changes in land use on C sequestration are likely to be larger than the effect of CO2-induced growth stimulation.

  6. Relationships between net primary productivity and forest stand age in U.S. forests

    NASA Astrophysics Data System (ADS)

    He, Liming; Chen, Jing M.; Pan, Yude; Birdsey, Richard; Kattge, Jens

    2012-09-01

    Net primary productivity (NPP) is a key flux in the terrestrial ecosystem carbon balance, as it summarizes the autotrophic input into the system. Forest NPP varies predictably with stand age, and quantitative information on the NPP-age relationship for different regions and forest types is therefore fundamentally important for forest carbon cycle modeling. We used four terms to calculate NPP: annual accumulation of live biomass, annual mortality of aboveground and belowground biomass, foliage turnover to soil, and fine root turnover in soil. For U.S. forests the first two terms can be reliably estimated from the Forest Inventory and Analysis (FIA) data. Although the last two terms make up more than 50% of total NPP, direct estimates of these fluxes are highly uncertain due to limited availability of empirical relationships between aboveground biomass and foliage or fine root biomass. To resolve this problem, we developed a new approach using maps of leaf area index (LAI) and forest age at 1 km resolution to derive LAI-age relationships for 18 major forest type groups in the USA. These relationships were then used to derive foliage turnover estimates using species-specific trait data for leaf specific area and longevity. These turnover estimates were also used to derive the fine root turnover based on reliable relationships between fine root and foliage turnover. This combination of FIA data, remote sensing, and plant trait information allows for the first empirical and reliable NPP-age relationships for different forest types in the USA. The relationships show a general temporal pattern of rapid increase in NPP in the young ages of forest type groups, peak growth in the middle ages, and slow decline in the mature ages. The predicted patterns are influenced by climate conditions and can be affected by forest management. These relationships were further generalized to three major forest biomes for use by continental-scale carbon cycle models in conjunction with

  7. Forest products industry of the future: Building a sustainable technology advantage for America`s forest products industry

    SciTech Connect

    1999-02-01

    The US forest, wood, and paper industry ranks as one of the most competitive forest products industries in the world. With annual shipments valued at nearly $267 billion, it employs over 1.3 million people and is currently among the top 10 manufacturing employers in 46 out of 50 states. Retaining this leadership position will depend largely on the industry`s success in developing and using advanced technologies. These technologies will enable manufacturing plants and forestry enterprises to maximize energy and materials efficiency and reduce waste and emissions, while producing high-quality, competitively priced wood and paper products. In a unique partnership, leaders in the forest products industry have teamed with the US Department of Energy`s Office of Industrial Technologies (OIT) to encourage cooperative research efforts that will help position the US forest products industry for continuing prosperity while advancing national energy efficiency and environmental goals.

  8. 36 CFR 223.278 - Sale of forest botanical products and collection of fees.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... the sale of forest botanical products shall be governed under 36 CFR part 223 Subpart G. ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Sale of forest botanical products and collection of fees. 223.278 Section 223.278 Parks, Forests, and Public Property FOREST...

  9. 36 CFR 223.278 - Sale of forest botanical products and collection of fees.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... the sale of forest botanical products shall be governed under 36 CFR part 223 Subpart G. ... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Sale of forest botanical products and collection of fees. 223.278 Section 223.278 Parks, Forests, and Public Property FOREST...

  10. 36 CFR 223.278 - Sale of forest botanical products and collection of fees.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... the sale of forest botanical products shall be governed under 36 CFR part 223 Subpart G. ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Sale of forest botanical products and collection of fees. 223.278 Section 223.278 Parks, Forests, and Public Property FOREST...

  11. 36 CFR 223.278 - Sale of forest botanical products and collection of fees.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... the sale of forest botanical products shall be governed under 36 CFR part 223 Subpart G. ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Sale of forest botanical products and collection of fees. 223.278 Section 223.278 Parks, Forests, and Public Property FOREST...

  12. Seasonal greenness variations in Amazon transitional forests in response to light, moisture, and land use

    NASA Astrophysics Data System (ADS)

    Ratana, P.; Huete, A. R.; Davies, K.; Restrepo-Coupe, N.

    2014-12-01

    The Amazon basin consists of structurally diverse tropical forest ecosystems resulting from unique functional responses to seasonal rainfall and radiation drivers, as well as fire and land use pressures. Dry season intensity and duration increase from the tropical wet rainforests at the equator to cerrado at the south, with transitional forests (dry forest, semi-deciduous forests, and cerradão) and the arc of deforestation between the two large biomes. Little known of this distinctive transitional forest composition and functional types, yet this zone is disappearing rapidly due to anthropological pressure and warming events. We hypothesize that these gradients in light, moisture, land use pressures, and forest functional types should be expressed in distinct canopy-level seasonal responses observable in satellite time series data. Yet, recent studies have raised concerns of concurrent seasonal sun geometry influences that confound the interpretation of satellite-derived greenness and suggest that observed tropical forest seasonality are optical artifacts of shifting sun- sensor view geometries. In this study we investigated forest seasonal variations and greenness dynamics across the transition zone, with 10+ years (2003-2013) of Moderate Resolution Imaging Spectroradiometer (MODIS) enhanced vegetation index (EVI) data derived from the MCD43A1 product, for a fixed sun angle and fully corrected for sun- sensor view geometries. EVI values were extracted across two latitudinal transects across the Amazon transition zone sampling the eastern and central regions of the basin. We found a clear pattern of shifting forest greenness seasonality resulting from earlier onsets of the dry season from south to the north, irrespective of, and asynchronous with the solstice to equinox sun-earth geometry. From this seasonal profiles dry season greening in the wet forests and browning in the southern tropical dry forests could be observed. In many of the transitional forests, a

  13. The importance of intraspecific variation in tree responses to elevated [CO2]: breeding and management of future forests

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One strategy for managing forests to sustain or increase productivity under global climate change is to initiate breeding programs which maximize responses to elevated [CO2] within species. The basis for any breeding program is intraspecific variation in the traits of interest, and for forests, grow...

  14. Forest Products: Apparatus for Removing Bark from Whole Logs

    SciTech Connect

    Poole, L; Recca, L.

    1999-01-29

    Order this fact sheet now to learn how replacing the ''closed drum'' debarking technology method used in the forest industry with the ''open drum'' method saves time and production costs, and increases the economic value of wood products by inflicting less damage on logs so that they can be used for high-value economic products.

  15. Andean grasslands are as productive as tropical cloud forests

    NASA Astrophysics Data System (ADS)

    Oliveras, I.; Girardin, C.; Doughty, C. E.; Cahuana, N.; Arenas, C. E.; Oliver, V.; Huaraca Huasco, W.; Malhi, Y.

    2014-11-01

    We aim to assess net primary productivity (NPP) and carbon cycling in Andean tropical alpine grasslands (puna) and compare it with NPP of tropical montane cloud forests. We ask the following questions: (1) how do NPP and soil respiration of grasslands vary over the seasonal cycle? (2) how do burning and grazing affect puna productivity? (3) if the montane forest expands into the puna, what will be the resulting change in productivity? The study sites are located at the South-eastern Peruvian Andes; one grassland site and the forest sites are in Wayqecha biological station, and another grassland site in Manu National Park. At each grassland site, we selected a burnt and an unburnt area, installed unfenced and fenced transects in each area, and monitored above-ground productivity (NPPAG), below-ground productivity (NPPBG) and soil respiration (Rs) for 2 yr. In the forest, we monitored NPPAG, NPPBG and Rs for 2-4 yr. Grassland NPP varied between 4.6 ± 0.25 (disturbed areas) to 15.3 ± 0.9 Mg C ha-1 yr-1 (undisturbed areas) and cloud forest NPP was between 7.05 ± 0.39 and 8.0 ± 0.47 Mg C ha-1 yr-1, while soil carbon stocks were in the range of 126 ± 22 to 285 ± 31 Mg C ha-1. There were no significant differences on NPP between the puna and forest sites. The most undisturbed site had significantly higher NPP than other grassland sites, but no differences were found when relating grazing and fire at other sites. There were lower residence times of above-ground biomass compared to below-ground biomass. There was a strong seasonal signal on grassland NPPAG and NPPBG, with a shift on allocation at the beginning of the austral summer. High elevation tropical grasslands can be as productive as adjacent cloud forests, but have very different carbon cycling and retention properties than cloud forests.

  16. Idiosyncratic responses of Amazonian birds to primary forest disturbance.

    PubMed

    Moura, Nárgila G; Lees, Alexander C; Aleixo, Alexandre; Barlow, Jos; Berenguer, Erika; Ferreira, Joice; Mac Nally, Ralph; Thomson, James R; Gardner, Toby A

    2016-03-01

    As humans continue to alter tropical landscapes across the world, it is important to understand what environmental factors help determine the persistence of biodiversity in modified ecosystems. Studies on well-known taxonomic groups can offer critical insights as to the fate of biodiversity in these modified systems. Here we investigated species-specific responses of 44 forest-associated bird species with different behavioural traits to forest disturbance in 171 transects distributed across 31 landscapes in two regions of the eastern Brazilian Amazon. We investigated patterns of species occurrence in primary forests varyingly disturbed by selective-logging and fire and examined the relative importance of local, landscape and historical environmental variables in determining species occurrences. Within undisturbed and disturbed primary forest transects, we found that distance to forest edge and the biomass of large trees were the most important predictors driving the occurrence of individual species. However, we also found considerable variation in species responses to different environmental variables as well as inter-regional variation in the responses of the same species to the same environmental variables. We advocate the utility of using species-level analyses to complement community-wide responses in order to uncover highly variable and species-specific responses to environmental change that remain so poorly understood. PMID:26566810

  17. Use of Current 2010 Forest Disturbance Monitoring Products for the Conterminous United States in Aiding a National Forest Threat Early Warning System

    NASA Technical Reports Server (NTRS)

    Spruce, Joseph P.; Hargrove, William; Gasser, J.; Smoot, J.; Kuper, P.

    2010-01-01

    This presentation discusses contributions of near real time (NRT) MODIS forest disturbance detection products for the conterminous United States to an emerging national forest threat early warning system (EWS). The latter is being developed by the USDA Forest Service s Eastern and Western Environmental Threat Centers with help from NASA Stennis Space Center and the Oak Ridge National Laboratory. Building off work done in 2009, this national and regional forest disturbance detection and viewing capability of the EWS employs NRT MODIS NDVI data from the USGS eMODIS group and historical NDVI data from standard MOD13 products. Disturbance detection products are being computed for 24 day composites that are refreshed every 8 days. Products for 2010 include 42 dates of the 24 day composites. For each compositing date, we computed % change in forest maximum NDVI products for 2010 with respect to each of three historical baselines of 2009, 2007-2009, and 2003-2009,. The three baselines enable one to view potential current, recent, and longer term forest disturbances. A rainbow color table was applied to each forest change product so that potential disturbances (NDVI drops) were identified in hot color tones and growth (NDVI gains) in cold color tones. Example products were provided to end-users responsible for forest health monitoring at the Federal and State levels. Large patches of potential forest disturbances were validated based on comparisons with available reference data, including Landsat and field survey data. Products were posted on two internet mapping systems for US Forest Service internal and collaborator use. MODIS forest disturbance detection products were computed and posted for use in as little as 1 day after the last input date of the compositing period. Such products were useful for aiding aerial disturbance detection surveys and for assessing disturbance persistence on both inter- and intra-annual scales. Multiple 2010 forest disturbance events were

  18. Use of Current 2010 Forest Disturbance Monitoring Products for the Conterminous United States in Aiding a National Forest Threat Early Warning System

    NASA Astrophysics Data System (ADS)

    Spruce, J.; Hargrove, W. W.; Gasser, J.; Smoot, J.; Kuper, P.

    2010-12-01

    This presentation discusses contributions of near real time (NRT) MODIS forest disturbance detection products for the conterminous United States to an emerging national forest threat early warning system (EWS). The latter is being developed by the USDA Forest Service’s Eastern and Western Environmental Threat Centers with help from NASA Stennis Space Center and the Oak Ridge National Laboratory. Building off work done in 2009, this national and regional forest disturbance detection and viewing capability of the EWS employs NRT MODIS NDVI data from the USGS eMODIS group and historical NDVI data from standard MOD13 products. Disturbance detection products are being computed for 24 day composites that are refreshed every 8 days. Products for 2010 include 42 dates of the 24 day composites. For each compositing date, we computed % change in forest maximum NDVI products for 2010 with respect to each of three historical baselines of 2009, 2007-2009, and 2003-2009. The three baselines enable one to view potential current, recent, and longer term forest disturbances. A rainbow color table was applied to each forest change product so that potential disturbances (NDVI drops) were identified in hot color tones and growth (NDVI gains) in cold color tones. Example products were provided to end-users responsible for forest health monitoring at the Federal and State levels. Large patches of potential forest disturbances were validated based on comparisons with available reference data, including Landsat and field survey data. Products were posted on two internet mapping systems for US Forest Service internal and collaborator use. MODIS forest disturbance detection products were computed and posted for use in as little as 1 day after the last input date of the compositing period. Such products were useful for aiding aerial disturbance detection surveys and for assessing disturbance persistence on both inter- and intra-annual scales. Multiple 2010 forest disturbance events were

  19. Forest response and recovery following disturbance in upland forests of the Atlantic Coastal Plain

    PubMed Central

    Schäfer, Karina V. R.; Renninger, Heidi J.; Carlo, Nicholas J.; Vanderklein, Dirk W.

    2014-01-01

    Carbon and water cycling of forests contribute significantly to the Earth's overall biogeochemical cycling and may be affected by disturbance and climate change. As a larger body of research becomes available about leaf-level, ecosystem and regional scale effects of disturbances on forest ecosystems, a more mechanistic understanding is developing which can improve modeling efforts. Here, we summarize some of the major effects of physical and biogenic disturbances, such as drought, prescribed fire, and insect defoliation, on leaf and ecosystem-scale physiological responses as well as impacts on carbon and water cycling in an Atlantic Coastal Plain upland oak/pine and upland pine forest. During drought, stomatal conductance and canopy stomatal conductance were reduced, however, defoliation increased conductance on both leaf-level and canopy scale. Furthermore, after prescribed fire, leaf-level stomatal conductance was unchanged for pines but decreased for oaks, while canopy stomatal conductance decreased temporarily, but then rebounded the following growing season, thus exhibiting transient responses. This study suggests that forest response to disturbance varies from the leaf to ecosystem level as well as species level and thus, these differential responses interplay to determine the fate of forest structure and functioning post disturbance. PMID:25018759

  20. Forest herb layer response to long-term light deficit along a forest developmental series

    NASA Astrophysics Data System (ADS)

    Plue, J.; Van Gils, B.; De Schrijver, A.; Peppler-Lisbach, C.; Verheyen, K.; Hermy, M.

    2013-11-01

    Temperate deciduous forest communities are slow-changing systems, with herbaceous understorey communities displaying a delayed response to overstorey canopy and light dynamics. While light availability constrains herbaceous understorey diversity and composition in space and time, its response in the long-term absence of light has seldom been quantified, particularly as it is often confounded by covariation in soil conditions. We studied a developmental high-forest series in two widespread NW-European temperate deciduous forest communities with different dominant canopy tree species: Stellario-Carpinetum (Oak-hornbeam canopy) and Milio-Fagetum (Beech canopy). All plots had soil conditions which were not significantly different, enabling investigation into the direct effects of the long-term absence of light on the herbaceous understorey, disentangled from the confounding effects of soil variation. Plant species richness measures declined with canopy cover continuity in the herb layer of the oak-hornbeam stands, whereas richness in the herb layer of the beech stands displayed a unimodal response. Nonetheless, in both plant communities, species richness and closed-forest species richness were negatively affected by the extended absence of light in stands with the longest period of continuous canopy cover. The long-term limitation or decline in quantitative and qualitative light availability as a result of extended periods of canopy cover was shown to be the primary driver behind losses in alpha-diversity, community composition turn-over and individual species dynamics. Heliophilous species were lost from both communities, while closed-forest species also declined, as a direct consequence of the prolonged period without ample light on the forest floor. This study demonstrates how the herb layer is affected by the absence of light on the forest floor mediated by long periods of continuous canopy cover. Despite different temporal responses in herb layer richness and

  1. Sensitivity of tropical forest aboveground productivity to climate anomalies in SW Costa Rica

    NASA Astrophysics Data System (ADS)

    Hofhansl, Florian; Kobler, Johannes; Ofner, Joachim; Drage, Sigrid; Pölz, Eva-Maria; Wanek, Wolfgang

    2014-12-01

    The productivity of tropical forests is driven by climate (precipitation, temperature, and light) and soil fertility (geology and topography). While large-scale drivers of tropical productivity are well established, knowledge on the sensitivity of tropical lowland net primary production to climate anomalies remains scarce. We here analyze seven consecutive years of monthly recorded tropical forest aboveground net primary production (ANPP) in response to a recent El Niño-Southern Oscillation (ENSO) anomaly. The ENSO transition period resulted in increased temperatures and decreased precipitation during the El Niño dry period, causing a decrease in ANPP. However, the subsequent La Niña wet period caused strong increases in ANPP such that drought-induced reductions were overcompensated. Most strikingly, the climatic controls differed between canopy production (CP) and wood production (WP). Whereas CP showed strong seasonal variation but was not affected by ENSO, WP decreased significantly in response to a 3°C increase in annual maximum temperatures during the El Niño period but subsequently recovered to above predrought levels during the La Niña period. Moreover, the climate sensitivity of tropical forest ANPP components was affected by local topography (water availability) and disturbance history (species composition). Our results suggest that projected increases in temperature and dry season length could impact tropical carbon sequestration by shifting ANPP partitioning toward decreased WP, thus decreasing the carbon storage of highly productive lowland forests. We conclude that the impact of climate anomalies on tropical forest productivity is strongly related to local site characteristics and will therefore likely prevent uniform responses of tropical lowland forests to projected global changes.

  2. Monitoring Regional Forest Disturbances across the US with near Real Time MODIS NDVI Products Resident to the ForWarn Forest Threat Early Warning System

    NASA Technical Reports Server (NTRS)

    Spruce, Joseph P.; Hargrove, William W.; Gasser, Gerald

    2013-01-01

    Forest threats across the US have become increasingly evident in recent years. Sometimes these have resulted in regionally evident disturbance progressions (e.g., from drought, bark beetle outbreaks, and wildfires) that can occur across multiyear durations and have resulted in extensive forest overstory mortality. In addition to stand replacement disturbances, other forests are subject to ephemeral, sometimes yearly defoliation from various insects and varying types and intensities of ephemeral damage from storms. Sometimes, after prolonged severe disturbance, signs of recovery in terms of Normalized Difference Vegetation Index (NDVI) can occur. The growing prominence and threat of forest disturbances in part have led to the formation and implementation of the 2003 Healthy Forest Restoration Act which mandated that national forest threat early warning system be developed and deployed. In response, the US Forest Service collaborated with NASA, DOE Oakridge National Laboratory, and the USGS Eros Data Center to build and roll-out the near real time ForWarn early warning system for monitoring regionally evident forest disturbances. Given the diversity of disturbance types, severities, and durations, ForWarn employs multiple historical baselines that are used with current NDVI to derive a suite of six forest change products that are refreshed every 8 days. ForWarn employs daily quarter kilometer MODIS NDVI data from the Aqua and Terra satellites, including MOD13 data for deriving historical baseline NDVIs and eMODIS 7 NDVI for compiling current NDVI. In doing so, the Time Series Product Tool and the Phenological Parameters Estimation Tool are used to temporally de-noise, fuse, and aggregate current and historical MODIS NDVIs into 24 day composites refreshed every 8 days with 46 dates of products per year. The 24 day compositing interval enables disturbances to be detected, while minimizing the frequency of residual atmospheric contamination. Forest change products are

  3. Forest and wood products role in carbon sequestration

    SciTech Connect

    Sampson, R.N.

    1997-12-31

    An evaluation of the use of U.S. forests and forest products for carbon emission mitigation is presented. The current role of forests in carbon sequestration is described in terms of regional differences and forest management techniques. The potential for increasing carbon storage by converting marginal crop and pasture land, increasing timberland growth, reducing wildfire losses, and changing timber harvest methods is examined. Post-harvest carbon flows, environmental impacts of wood products, biomass energy crops, and increased use of energy-conserving trees are reviewed for their potential in reducing or offsetting carbon emissions. It is estimated that these techniques could offset 20 to 40 percent of the carbon emitted annually in the U.S. 39 refs., 5 tabs.

  4. Forest Productivity and Diversity: Using Ecological Theory and Landscape Models to Guide Sustainable Forest Management

    SciTech Connect

    Huston, M.A.

    1998-11-01

    distribution of various plants and animals. These models can be, used to predict the patterns of forest type and structure that develop in response to variation in productivity and disturbance across complex landscapes, as well as species diversity and the distribution and population fluctuations of threatened species in specific regions.

  5. Nanotechnology for the Forest Products Industry Vision and Technology Roadmap

    SciTech Connect

    Atalla, Rajai; Beecher, James; Caron, Robert; Catchmark, Jeffrey; Deng, Yulin; Glasser, Wolfgang; Gray, Derek; Haigler, Candace; Jones, Philip; Joyce, Margaret; Kohlman, Jane; Koukoulas, Alexander; Lancaster, Peter; Perine, Lori; Rodriguez, Augusto; Ragauskas, Arthur; Wegner, Theodore; Zhu, Junyong

    2005-03-01

    A roadmap for Nanotechnology in the Forest Products Industries has been developed under the umbrella of the Agenda 2020 program overseen by the CTO committee. It is expected that the use of new analytical techniques and methodologies will allow us to understand the complex nature of wood based materials and allow the dramatically enhanced use of the major strategic asset the US has in renewable, recyclable resources based on its well managed Forests.

  6. 25 CFR 163.19 - Contracts for the sale of forest products.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Contracts for the sale of forest products. 163.19 Section 163.19 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.19 Contracts for the sale of forest products. (a) In sales of forest products with an...

  7. Birds in Anthropogenic Landscapes: The Responses of Ecological Groups to Forest Loss in the Brazilian Atlantic Forest.

    PubMed

    Morante-Filho, José Carlos; Faria, Deborah; Mariano-Neto, Eduardo; Rhodes, Jonathan

    2015-01-01

    Habitat loss is the dominant threat to biodiversity and ecosystem functioning in terrestrial environments. In this study, we used an a priori classification of bird species based on their dependence on native forest habitats (forest-specialist and habitat generalists) and specific food resources (frugivores and insectivores) to evaluate their responses to forest cover reduction in landscapes in the Brazilian Atlantic Forest. From the patch-landscapes approach, we delimited 40 forest sites, and quantified the percentage of native forest within a 2 km radius around the center of each site (from 6 - 85%). At each site, we sampled birds using the point-count method. We used a null model, a generalized linear model and a four-parameter logistic model to evaluate the relationship between richness and abundance of the bird groups and the native forest amount. A piecewise model was then used to determine the threshold value for bird groups that showed nonlinear responses. The richness and abundance of the bird community as a whole were not affected by changes in forest cover in this region. However, a decrease in forest cover had a negative effect on diversity of forest-specialist, frugivorous and insectivorous birds, and a positive effect on generalist birds. The species richness and abundance of all ecological groups were nonlinearly related to forest reduction and showed similar threshold values, i.e., there were abrupt changes in individuals and species numbers when forest amount was less than approximately 50%. Forest sites within landscapes with forest cover that was less than 50% contained a different bird species composition than more extensively forested sites and had fewer forest-specialist species and higher beta-diversity. Our study demonstrated the pervasive effect of forest reduction on bird communities in one of the most important hotspots for bird conservation and shows that many vulnerable species require extensive forest cover to persist. PMID:26083245

  8. Birds in Anthropogenic Landscapes: The Responses of Ecological Groups to Forest Loss in the Brazilian Atlantic Forest

    PubMed Central

    Morante-Filho, José Carlos; Rhodes, Jonathan

    2015-01-01

    Habitat loss is the dominant threat to biodiversity and ecosystem functioning in terrestrial environments. In this study, we used an a priori classification of bird species based on their dependence on native forest habitats (forest-specialist and habitat generalists) and specific food resources (frugivores and insectivores) to evaluate their responses to forest cover reduction in landscapes in the Brazilian Atlantic Forest. From the patch-landscapes approach, we delimited 40 forest sites, and quantified the percentage of native forest within a 2 km radius around the center of each site (from 6 - 85%). At each site, we sampled birds using the point-count method. We used a null model, a generalized linear model and a four-parameter logistic model to evaluate the relationship between richness and abundance of the bird groups and the native forest amount. A piecewise model was then used to determine the threshold value for bird groups that showed nonlinear responses. The richness and abundance of the bird community as a whole were not affected by changes in forest cover in this region. However, a decrease in forest cover had a negative effect on diversity of forest-specialist, frugivorous and insectivorous birds, and a positive effect on generalist birds. The species richness and abundance of all ecological groups were nonlinearly related to forest reduction and showed similar threshold values, i.e., there were abrupt changes in individuals and species numbers when forest amount was less than approximately 50%. Forest sites within landscapes with forest cover that was less than 50% contained a different bird species composition than more extensively forested sites and had fewer forest-specialist species and higher beta-diversity. Our study demonstrated the pervasive effect of forest reduction on bird communities in one of the most important hotspots for bird conservation and shows that many vulnerable species require extensive forest cover to persist. PMID:26083245

  9. Gross primary production of global forest ecosystems has been overestimated

    PubMed Central

    Ma, Jianyong; Yan, Xiaodong; Dong, Wenjie; Chou, Jieming

    2015-01-01

    Coverage rate, a critical variable for gridded forest area, has been neglected by previous studies in estimating the annual gross primary production (GPP) of global forest ecosystems. In this study, we investigated to what extent the coverage rate could impact forest GPP estimates from 1982 to 2011. Here we show that the traditional calculation without considering the coverage rate globally overestimated the forest gross carbon dioxide uptake by approximately 8.7%, with a value of 5.12 ± 0.23 Pg C yr−1, which is equivalent to 48% of the annual emissions from anthropogenic activities in 2012. Actually, the global annual GPP of forest ecosystems is approximately 53.71 ± 4.83 Pg C yr−1 for the past 30 years by taking the coverage rate into account. Accordingly, we argue that forest annual GPP calculated by previous studies has been overestimated due to the exaggerated forest area, and therefore, coverage rate may be a required factor to further quantify the global carbon cycle. PMID:26027557

  10. Forest gradient response in Sierran landscapes: The physical template

    USGS Publications Warehouse

    Urban, D.L.; Miller, C.; Halpin, P.N.; Stephenson, N.L.

    2000-01-01

    Vegetation pattern on landscapes is the manifestation of physical gradients, biotic response to these gradients, and disturbances. Here we focus on the physical template as it governs the distribution of mixed-conifer forests in California's Sierra Nevada. We extended a forest simulation model to examine montane environmental gradients, emphasizing factors affecting the water balance in these summer-dry landscapes. The model simulates the soil moisture regime in terms of the interaction of water supply and demand: supply depends on precipitation and water storage, while evapotranspirational demand varies with solar radiation and temperature. The forest cover itself can affect the water balance via canopy interception and evapotranspiration. We simulated Sierran forests as slope facets, defined as gridded stands of homogeneous topographic exposure, and verified simulated gradient response against sample quadrats distributed across Sequoia National Park. We then performed a modified sensitivity analysis of abiotic factors governing the physical gradient. Importantly, the model's sensitivity to temperature, precipitation, and soil depth varies considerably over the physical template, particularly relative to elevation. The physical drivers of the water balance have characteristic spatial scales that differ by orders of magnitude. Across large spatial extents, temperature and precipitation as defined by elevation primarily govern the location of the mixed conifer zone. If the analysis is constrained to elevations within the mixed-conifer zone, local topography comes into play as it influences drainage. Soil depth varies considerably at all measured scales, and is especially dominant at fine (within-stand) scales. Physical site variables can influence soil moisture deficit either by affecting water supply or water demand; these effects have qualitatively different implications for forest response. These results have clear implications about purely inferential approaches

  11. A Long Term View of Forest Response to Environmental Change: 25 Years of Studying Harvard Forest

    NASA Astrophysics Data System (ADS)

    Munger, J. W.; Wofsy, S. C.; Lindaas, J.; David, F.; David, O.

    2014-12-01

    Forests influence the budgets of greenhouse gases, and understanding how they will respond to environmental change is critical to accurately predicting future GHG trends. The time scale for climate change is long and forest growth is slow, thus very long measurement periods are required to observe meaningful forest response. We established an eddy flux tower within a mixed forest stand dominated by red oak and red maple at the Harvard Forest LTER site in 1989 where CO2, H2O and energy fluxes together with meteorological observations have been measured continuously. An array of plots for biometric measurements was established in 1993. Flux measurement at an adjacent hemlock stand began in 2000. Records of land use and disturbance and vegetation plot data extend back to 1907. The combined suite of measurements merges observations of instantaneous ecosystem responses to environmental forcing with details of vegetation dynamics and forest growth that represent the emergent properties relevant to long-term ecosystem change. Both the deciduous stand and hemlock stand are accumulating biomass. Each has added over 20 Mg-C ha-1 as woody biomass in trees >10cm dbh since 1990, even though the hemlock stand is older. Net carbon exchange shows enhanced uptake in early spring and late fall months in response to warmer temperatures and likely an increase in evergreen foliage at the deciduous site. Net carbon uptake efficiency at the deciduous stand has increased over time as well as indicated by peak NEE under optimum light conditions. The trend is only partly explained by variation in mean leaf area index and cannot be directly attributed to climate response. The combination of longer growing season and increased uptake efficiency yields a general trend of increasing annual NEE (Fig. 1). However, significant excursions in the trend highlight the sensitivity of forest carbon stocks. The pulse of high annual carbon uptake (peak 6 Mg-C ha-1y-1 in 2008) from 2000-2008 is only

  12. An exploratory assessment of the attitudes of Chinese wood products manufacturers towards forest certification.

    PubMed

    Chen, Juan; Innes, John L; Kozak, Robert A

    2011-11-01

    Interviews with Chinese forest products manufacturers were conducted to explore their attitudes towards forest certification and related issues. Participants comprised owners, CEOs, and managers in 20 Chinese wood products companies, including producers of furniture, doors, flooring, and various engineered wood products. The interviews were used to analyze the extent to which participants were considering adopting forest certification and what might motivate such a decision. This was done by assessing their awareness and knowledge of certification. The results indicated that participants' understanding of forest certification was extremely low, despite major efforts in China to raise awareness of the issue. Potential economic benefits were the most frequently cited reason to adopt certification, including gaining or maintaining competitive advantage over their industry counterparts, improved access to both domestic and export markets, better customer recognition, and enhanced corporate responsibility practices. Some interviewees (3 out of 20) considered that certification would become a mandatory requirement or industry standard, and that this would be the only viable motivation for certification given that the financial benefits were potentially limited. According to the participants, the main differences between certified and uncertified wood products operations related to improved market access and public image. Interviewees felt that cooperation between and support from governments and the forest industry would enable the enhanced awareness of certification amongst manufacturers and the general public. This, in turn, could serve to stimulate demand for certified products. PMID:21816537

  13. RESPONSE AND FEEDBACKS OF FOREST ECOSYSTEMS TO GLOBAL CLIMATE CHANGE

    EPA Science Inventory

    The accumulation of greenhouse gases in the atmosphere over the past century is projected to cause a warming of the Earth. Climate Change predictions vary by region and terrestrial biosphere response, and feedbacks will be ecosystem specific. Forests play a major role in the Eart...

  14. How to manage oak forests for acorn production

    SciTech Connect

    Johnson, P.S.

    1994-03-01

    Oak forests are life support systems for the many animals that live in them. Acorns, a staple product of oak forests, are eaten by many species of birds and mammals including deer, bear, squirrels, mice, rabbits, foxes, raccoons, grackles, turkey, grouse, quail, blue jays, woodpeckers, and water-fowl. The population and health and wildlife often rise, and fall with the cyclic production of acorns. Acorns' importance to wildlife is related to several factors including their widespread occurrence, palatability, nutritiousness, and availability during the critical fall and winter period.

  15. University of Maine Integrated Forest Product Refinery (IFPR) Technology Research

    SciTech Connect

    Pendse, Hemant P.

    2010-11-23

    This project supported research on science and technology that forms a basis for integrated forest product refinery for co-production of chemicals, fuels and materials using existing forest products industry infrastructure. Clear systems view of an Integrated Forest Product Refinery (IFPR) allowed development of a compelling business case for a small scale technology demonstration in Old Town ME for co-production of biofuels using cellulosic sugars along with pulp for the new owners of the facility resulting in an active project on Integrated Bio-Refinery (IBR) at the Old Town Fuel & Fiber. Work on production of advanced materials from woody biomass has led to active projects in bioplastics and carbon nanofibers. A lease for 40,000 sq. ft. high-bay space has been obtained to establish a Technology Research Center for IFPR technology validation on industrially relevant scale. UMaine forest bioproducts research initiative that began in April 2006 has led to establishment of a formal research institute beginning in March 2010.

  16. Sources or sinks? The responses of tropical forests to current and future climate and atmospheric composition.

    PubMed Central

    Clark, Deborah A

    2004-01-01

    How tropical rainforests are responding to the ongoing global changes in atmospheric composition and climate is little studied and poorly understood. Although rising atmospheric carbon dioxide (CO2) could enhance forest productivity, increased temperatures and drought are likely to diminish it. The limited field data have produced conflicting views of the net impacts of these changes so far. One set of studies has seemed to point to enhanced carbon uptake; however, questions have arisen about these findings, and recent experiments with tropical forest trees indicate carbon saturation of canopy leaves and no biomass increase under enhanced CO2. Other field observations indicate decreased forest productivity and increased tree mortality in recent years of peak temperatures and drought (strong El Niño episodes). To determine current climatic responses of forests around the world tropics will require careful annual monitoring of ecosystem performance in representative forests. To develop the necessary process-level understanding of these responses will require intensified experimentation at the whole-tree and stand levels. Finally, a more complete understanding of tropical rainforest carbon cycling is needed for determining whether these ecosystems are carbon sinks or sources now, and how this status might change during the next century. PMID:15212097

  17. Tropical forest responses to increasing [CO2]: current knowledge and opportunities for future research

    SciTech Connect

    Cernusak, Lucas; Winter, Klaus; Dalling, James; Holtum, Joseph; Jaramillo, Carlos; Korner, Christian; Leakey, Andrew D.B.; Norby, Richard J; Poulter, Benjamin; Turner, Benjamin; Wright, S. Joseph

    2013-01-01

    Elevated atmospheric [CO2] (ca) will undoubtedly affect the metabolism of tropical forests worldwide; however, critical aspects of how tropical forests will respond remain largely unknown. Here we review the current state of knowledge about physiological and ecological responses, with the aim of providing a framework that can help to guide future experimental research. Modelling studies have indicated that elevated ca can potentially stimulate photosynthesis more in the tropics than at higher latitudes, because suppression of photorespiration by elevated ca increases with temperature. However, canopy leaves in tropical forests could also potentially reach a high temperature threshold under elevated ca that will moderate the rise in photosynthesis. Belowground responses, including fine root production, nutrient foraging, and soil organic matter processing, will be especially important to the integrated ecosystem response to elevated CO2. Water-use efficiency will increase as ca rises, potentially impacting upon soil moisture status and nutrient availability. Recruitment may be differentially altered for some functional groups, potentially decreasing ecosystem carbon storage. Whole-forest CO2 enrichment experiments are urgently needed to test predictions of tropical forest functioning under elevated ca. Smaller scale experiments in the understory and in gaps would also be informative, and could provide stepping stones toward stand-scale manipulations.

  18. Streamflow response to increasing precipitation extremes altered by forest management

    NASA Astrophysics Data System (ADS)

    Kelly, Charlene N.; McGuire, Kevin J.; Miniat, Chelcy Ford; Vose, James M.

    2016-04-01

    Increases in extreme precipitation events of floods and droughts are expected to occur worldwide. The increase in extreme events will result in changes in streamflow that are expected to affect water availability for human consumption and aquatic ecosystem function. We present an analysis that may greatly improve current streamflow models by quantifying the impact of the interaction between forest management and precipitation. We use daily long-term data from paired watersheds that have undergone forest harvest or species conversion. We find that interactive effects of climate change, represented by changes in observed precipitation trends, and forest management regime, significantly alter expected streamflow most often during extreme events, ranging from a decrease of 59% to an increase of 40% in streamflow, depending upon management. Our results suggest that vegetation might be managed to compensate for hydrologic responses due to climate change to help mitigate effects of extreme changes in precipitation.

  19. Forest response to heat waves at the dry timberline

    NASA Astrophysics Data System (ADS)

    Yakir, D.; Rotenberg, E.; Tatrinov, F.; Ogee, J.; Maseyk, K.

    2012-04-01

    Predictions of climate change consistently indicate continuous warming and drying for the entire Mediterranean basin and other regions during the next century. Investigating forest functioning at the current dry and hot "timberline" has therefore implications for predicting future forest distribution. In such investigations we should consider the forest adjustments to extreme conditions both at the long-term average climate basis, as at the time-scale of episodic extreme events, such as heat waves and droughts. Investigating both aspects in a 45-yr old semi-arid pine forest at the dry timberline (<300 mm annual rainfall) we observe adjustments that improve carbon-, nitrogen- and water- use efficiencies. An important aspect in the ecosystem sustainability is its ability to rapidly recover from extreme conditions, both at the short-term and the seasonal scale. A remarkable example is provided by the episodes (usually 2-4 days) of Easterly dry and hot air that are common in spring (so-called "Hamsin" events). During these events air temperature increases and relative humidity decreases within hours by 10˚C and 40%, respectively. Net ecosystem CO2 exchange (NEE) and photosynthesis (GPP) sharply decline, predominantly in response to the drastic increase in vapor pressure deficit (up to 6kPa), but then show full recovery to the pre-stress values within 24 h past the event. Similarly, following 5-6 months of seasonal drought, the forest resumes high photosynthetic activity within ~5 days following the first rain episode of about 10 mm in the fall. We show that these transient responses are useful in partitioning between the ecosystem responses to short-term atmosphere-driven stress and longer-term soil moisture stress. An ecosystem model (MuSICA) was used to test our understandings of underlying processes, and our ability to account for such differential responses.

  20. Responses of aboveground and belowground forest carbon stocks to disturbances in boreal forests of Northeastern China

    NASA Astrophysics Data System (ADS)

    Huang, Chao; He, Hong S.; Hawbaker, Todd J.; Liang, Yu; Gong, Peng; Wu, Wuzhiwei; Zhu, Zhiliang

    2016-04-01

    Boreal forests represents about 1/3 of forest area and 1/3 of forest carbon on earth. Carbon dynamics of boreal forests are sensitive to climate change, natural (e.g., fire) and anthropogenic (e.g., harvest) disturbances. Field-based studies suggest that disturbances alter species composition, stand structure, and litter decomposition, and have significant effects on boreal forest carbon dynamics. Most of these studies, however, covered a relatively short period of time (e.g., few decades), which is limited in revealing such long-term effects of disturbances. Models are therefore developed as important tools in exploring the long-term (e.g., hundreds of years) effects of disturbances on forest carbon dynamics. In this study, we applied a framework of coupling forest ecosystem and landscape model to evaluating the effect of fire, harvest and their interactions on carbon stocks in a boreal forest landscape of Northeastern China. We compared the simulation results under fire, harvest and fire-harvest interaction scenarios with the simulated value of succession scenario at 26 landtypes over 150 years at a 10-year time step. Our results suggest that aboveground and belowground carbon are significantly reduced by fire and harvest over 150years. Fire reduced aboveground carbon by 2.3±0.6 ton/ha, harvest by 6.0±1.4 ton/ha, and fire and harvest interaction by 8.0±1.9 tons/ha. Fire reduced belowground carbon by 4.6±3.4 ton/ha, harvest by 5.0±3.5 ton/ha, and fire-harvest interaction by 5.7±3.7 tons/ha. The divergent response of carbon stocks among landtypes and between disturbance scenarios was due to the spatial interactions between fire, harvest, and species composition. Our results indicated that boreal forests carbon stocks prediction needs to consider the effects of fire and harvest for improving the estimation accuracy.

  1. Examining the ecosystem health and sustainability of the world's largest mangrove forest using multi-temporal MODIS products.

    PubMed

    Ishtiaque, Asif; Myint, Soe W; Wang, Chuyuan

    2016-11-01

    Sweeping across Bangladesh and India, the Sundarbans forest is the world's largest contiguous mangrove forest. Although the human population density is high at the edge, Sundarbans has not encountered significant areal transformation in the last four decades. However, we argue that forest degradation can occur discontinuously within the forest without alteration of the entire forest area. In this paper, we used MODIS land products to compare the spatiotemporal ecological dynamics of the Bangladesh and Indian part of this mangrove forest between 2000 and 2010. We used the following 5 ecological parameters for our analysis: the Percent Tree Cover (PTC), Enhanced Vegetation Index (EVI), Net Primary Productivity (NPP), Leaf Area Index (LAI), and Evapotranspiration (ET). Our pixel-based time-series trend analysis for each MODIS image stack, using an ordinary least square (OLS) regression method, showed that forest degradation is happening in fragmented parcels within the forest. The degradation rate is comparatively higher in the Bangladesh part than in the Indian part of Sundarbans. Compartments 8, 10, 12, and 15 in the Bangladesh part, in particular, show high degradation, while compartment 48 and the southern edge of 45 show slight increases in PTC or EVI. Forest degradation in the Indian part of the forest is evident in the National Park and Reserve Forest blocks; however, no substantial degradation is evident in the western section. We have identified certain anthropogenic stressors (i.e., oil pollution, shrimp farming) and natural stressors (i.e., increased salinity, cyclones, forest fire) which might be responsible for the observed degradation. We have provided sustainable planning options and policy transformation alternatives for those areas under pressure from these stressors. We anticipate that our analysis of forest degradation will help management agencies, conservators, and policy makers achieve better management of this world's largest mangrove forest for

  2. Sustainable forest management and impacts on forest responses to a changing climate

    NASA Astrophysics Data System (ADS)

    Stover, D. B.; Parker, G.; Riutta, T.; Capretz, R.; Murthy, I.; Haibao, R.; Bebber, D.

    2009-12-01

    Impacts from human activities at varying scales and intensities have a profound influence on forest carbon dynamics in addition to interactions with climate. As such, forest carbon stocks and fluxes are among the least well-defined elements of the global carbon cycle, and great uncertainty remains in predicting the effect of climate change on forest dynamics. In some cases, these management-climate interactions are well known, but often represent a fundamental gap in our understanding of ecosystem responses and are likely to be important in improving modeling of climate change, and in valuing forest carbon. To improve understanding of human induced forest management-climate interactions, a network of permanent study plots has been established in five sites around the world - in the US, UK, Brazil, India and China. The sites are near larger global monitoring (Smithsonian CTFS) plots to facilitate comparisons. At each site, a series of 1-ha plots have been placed in forest stands with differing management regimes and histories. Utilizing citizen scientists from HSBC bank, all trees >5 cm dbh are tagged, mapped, identified to species, and diameter is recorded within each plot. A subset of trees have dendrometer bands attached, to record seasonal growth. Dead wood and litterfall samples are taken, and microclimate is recorded with automatic sensors. Serial measurements will allow correlation of forest dynamics with weather. Although the studies are at an early stage current results indicate above-ground biomass estimates are 102-288 Mg ha-1 for intermediate and mature Liriodendron tulipifera-dominated stands in the US, respectively. In India, mature semi-natural evergreen forests biomass estimates are 192-235 Mg ha-1 while plantation and semi-natural core forests in the UK are estimated at 211-292 Mg ha-1. Successional Atlantic forests in Brazil are estimated to contain 192-235 Mg ha-1. In the US, initial results have demonstrated dramatic differences in microclimate

  3. 29 CFR 780.1016 - Use of evergreens and forest products.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Use of evergreens and forest products. 780.1016 Section 780... Labor Provisions Under Section 13(d) Requirements for Exemption § 780.1016 Use of evergreens and forest products. Harvesting of evergreens and other forest products is exempt only when these products will...

  4. 29 CFR 780.1016 - Use of evergreens and forest products.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false Use of evergreens and forest products. 780.1016 Section 780... Labor Provisions Under Section 13(d) Requirements for Exemption § 780.1016 Use of evergreens and forest products. Harvesting of evergreens and other forest products is exempt only when these products will...

  5. 29 CFR 780.1016 - Use of evergreens and forest products.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Use of evergreens and forest products. 780.1016 Section 780... Labor Provisions Under Section 13(d) Requirements for Exemption § 780.1016 Use of evergreens and forest products. Harvesting of evergreens and other forest products is exempt only when these products will...

  6. 29 CFR 780.1016 - Use of evergreens and forest products.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 3 2014-07-01 2014-07-01 false Use of evergreens and forest products. 780.1016 Section 780... Labor Provisions Under Section 13(d) Requirements for Exemption § 780.1016 Use of evergreens and forest products. Harvesting of evergreens and other forest products is exempt only when these products will...

  7. 29 CFR 780.1016 - Use of evergreens and forest products.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false Use of evergreens and forest products. 780.1016 Section 780... Labor Provisions Under Section 13(d) Requirements for Exemption § 780.1016 Use of evergreens and forest products. Harvesting of evergreens and other forest products is exempt only when these products will...

  8. Nut Production in Bertholletia excelsa across a Logged Forest Mosaic: Implications for Multiple Forest Use

    PubMed Central

    Rockwell, Cara A.; Guariguata, Manuel R.; Menton, Mary; Arroyo Quispe, Eriks; Quaedvlieg, Julia; Warren-Thomas, Eleanor; Fernandez Silva, Harol; Jurado Rojas, Edwin Eduardo; Kohagura Arrunátegui, José Andrés Hideki; Meza Vega, Luis Alberto; Revilla Vera, Olivia; Valera Tito, Jonatan Frank; Villarroel Panduro, Betxy Tabita; Yucra Salas, Juan José

    2015-01-01

    Although many examples of multiple-use forest management may be found in tropical smallholder systems, few studies provide empirical support for the integration of selective timber harvesting with non-timber forest product (NTFP) extraction. Brazil nut (Bertholletia excelsa, Lecythidaceae) is one of the world’s most economically-important NTFP species extracted almost entirely from natural forests across the Amazon Basin. An obligate out-crosser, Brazil nut flowers are pollinated by large-bodied bees, a process resulting in a hard round fruit that takes up to 14 months to mature. As many smallholders turn to the financial security provided by timber, Brazil nut fruits are increasingly being harvested in logged forests. We tested the influence of tree and stand-level covariates (distance to nearest cut stump and local logging intensity) on total nut production at the individual tree level in five recently logged Brazil nut concessions covering about 4000 ha of forest in Madre de Dios, Peru. Our field team accompanied Brazil nut harvesters during the traditional harvest period (January-April 2012 and January-April 2013) in order to collect data on fruit production. Three hundred and ninety-nine (approximately 80%) of the 499 trees included in this study were at least 100 m from the nearest cut stump, suggesting that concessionaires avoid logging near adult Brazil nut trees. Yet even for those trees on the edge of logging gaps, distance to nearest cut stump and local logging intensity did not have a statistically significant influence on Brazil nut production at the applied logging intensities (typically 1–2 timber trees removed per ha). In one concession where at least 4 trees ha-1 were removed, however, the logging intensity covariate resulted in a marginally significant (0.09) P value, highlighting a potential risk for a drop in nut production at higher intensities. While we do not suggest that logging activities should be completely avoided in Brazil nut rich

  9. Nut Production in Bertholletia excelsa across a Logged Forest Mosaic: Implications for Multiple Forest Use.

    PubMed

    Rockwell, Cara A; Guariguata, Manuel R; Menton, Mary; Arroyo Quispe, Eriks; Quaedvlieg, Julia; Warren-Thomas, Eleanor; Fernandez Silva, Harol; Jurado Rojas, Edwin Eduardo; Kohagura Arrunátegui, José Andrés Hideki; Meza Vega, Luis Alberto; Revilla Vera, Olivia; Quenta Hancco, Roger; Valera Tito, Jonatan Frank; Villarroel Panduro, Betxy Tabita; Yucra Salas, Juan José

    2015-01-01

    Although many examples of multiple-use forest management may be found in tropical smallholder systems, few studies provide empirical support for the integration of selective timber harvesting with non-timber forest product (NTFP) extraction. Brazil nut (Bertholletia excelsa, Lecythidaceae) is one of the world's most economically-important NTFP species extracted almost entirely from natural forests across the Amazon Basin. An obligate out-crosser, Brazil nut flowers are pollinated by large-bodied bees, a process resulting in a hard round fruit that takes up to 14 months to mature. As many smallholders turn to the financial security provided by timber, Brazil nut fruits are increasingly being harvested in logged forests. We tested the influence of tree and stand-level covariates (distance to nearest cut stump and local logging intensity) on total nut production at the individual tree level in five recently logged Brazil nut concessions covering about 4000 ha of forest in Madre de Dios, Peru. Our field team accompanied Brazil nut harvesters during the traditional harvest period (January-April 2012 and January-April 2013) in order to collect data on fruit production. Three hundred and ninety-nine (approximately 80%) of the 499 trees included in this study were at least 100 m from the nearest cut stump, suggesting that concessionaires avoid logging near adult Brazil nut trees. Yet even for those trees on the edge of logging gaps, distance to nearest cut stump and local logging intensity did not have a statistically significant influence on Brazil nut production at the applied logging intensities (typically 1-2 timber trees removed per ha). In one concession where at least 4 trees ha-1 were removed, however, the logging intensity covariate resulted in a marginally significant (0.09) P value, highlighting a potential risk for a drop in nut production at higher intensities. While we do not suggest that logging activities should be completely avoided in Brazil nut rich

  10. Quantifying the missing link between albedo and productivity of boreal forests

    NASA Astrophysics Data System (ADS)

    Hovi, Aarne; Liang, Jingjing; Korhonen, Lauri; Kobayashi, Hideki; Rautiainen, Miina

    2016-04-01

    Albedo and fraction of absorbed photosynthetically active radiation (FAPAR) determine the shortwave radiation balance and productivity of forests. Several studies have examined the relation between forest structure and albedo in the boreal zone. Studies regarding FAPAR are fewer and the relations between albedo and FAPAR are still poorly understood. To study these relations we simulated shortwave black sky albedo and canopy FAPAR, using the FRT forest reflectance model. We used two sets of field plots as input data. The plots were located in Alaska, USA (N = 584) and in Finland (N = 506) between Northern latitudes of 60° and 68° , and they represent naturally grown and more intensively managed (regularly thinned) forests, respectively. The simulations were carried out with sun zenith angles (SZA) typical to the biome, ranging from 40° to 80° . The simulated albedos in coniferous plots decreased with increasing tree height, whereas canopy FAPAR showed an opposite trend. The albedo of broadleaved plots was notably higher than that of coniferous plots. No species differences in canopy FAPAR were seen, except for pine forests in Finland that showed lowest FAPAR among species. Albedo and canopy FAPAR were negatively correlated (r ranged from -0.93 to -0.69) in coniferous plots. The correlations were notably weaker (r ranged from -0.64 to 0.05) if plots with broadleaved trees were included. To show the influence of forest management, we further examined the response of albedo and FAPAR to forest density (basal area) and fraction of broadleaved trees. Plots with low basal area showed high albedos but also low canopy FAPAR. When comparing the sparse plots to dense ones, the relative decrease in canopy FAPAR was larger than the relative increase in albedo. However, at large SZAs the basal area could be lowered to approx. 20 m2 ha‑1 before FAPAR was notably reduced. Increasing the proportion of broadleaved trees from 0% to 100% increased the albedos to approximately

  11. N{sub 2}O production pathways in the subtropical acid forest soils in China

    SciTech Connect

    Zhang Jinbo; Cai Zucong; Zhu Tongbin

    2011-07-15

    To date, N{sub 2}O production pathways are poorly understood in the humid subtropical and tropical forest soils. A {sup 15}N-tracing experiment was carried out under controlled laboratory conditions to investigate the processes responsible for N{sub 2}O production in four subtropical acid forest soils (pH<4.5) in China. The results showed that denitrification was the main source of N{sub 2}O emission in the subtropical acid forest soils, being responsible for 56.1%, 53.5%, 54.4%, and 55.2% of N{sub 2}O production, in the GC, GS, GB, and TC soils, respectively, under aerobic conditions (40%-52%WFPS). The heterotrophic nitrification (recalcitrant organic N oxidation) accounted for 27.3%-41.8% of N{sub 2}O production, while the contribution of autotrophic nitrification was little in the studied subtropical acid forest soils. The ratios of N{sub 2}O-N emission from total nitrification (heterotrophic+autotrophic nitrification) were higher than those in most previous references. The soil with the lowest pH and highest organic-C content (GB) had the highest ratio (1.63%), suggesting that soil pH-organic matter interactions may exist and affect N{sub 2}O product ratios from nitrification. The ratio of N{sub 2}O-N emission from heterotrophic nitrification varied from 0.02% to 25.4% due to soil pH and organic matter. Results are valuable in the accurate modeling of N2O production in the subtropical acid forest soils and global budget. - Highlights: {yields} We studied N{sub 2}O production pathways in subtropical acid forest soil under aerobic conditions. {yields} Denitrification was the main source of N{sub 2}O production in subtropical acid forest soils. {yields} Heterotrophic nitrification accounted for 27.3%-41.8% of N{sub 2}O production. {yields} While, contribution of autotrophic nitrification to N{sub 2}O production was little. {yields} Ratios of N{sub 2}O-N emission from nitrification were higher than those in most previous references.

  12. Monitoring the Philippine Forest Cover Change Using Ndvi Products of Remote Sensing Data

    NASA Astrophysics Data System (ADS)

    Torres, R. C.; Mouginis-Mark, P.; Wright, R.; Garbeil, H.; Craig, B.

    2004-12-01

    The Philippines has one of the world's fastest disappearing forest cover, which is being lost to natural processes and landscape-modifying human activities. Currently, forested landscape covers 24% (i.e., 7.2 million hectares) of the Philippines' total land area, of which only 800,000 hectares are considered as old-growth forests. Occasionally, volcanic activities and earthquakes cause large-scale impacts on the forest cover, but the systematic reduction of the country's forest has been sustained through unregulated logging operations and other human-induced landscape modification. Reforestation and watershed protection have become important public policy programs as forest denudation is linked to recent devastating landslides, debris flows and flashfloods. However, many watershed areas that are at risk to deforestation are hardly accessible to ground-based monitoring. A spaced-based monitoring system facilitates an efficient and timely response to changes in the quality and extent of the Philippine forest cover. This monitoring system relies in the generation of Normalized Difference Vegetation Index (NDVI) products from the red and infrared bands of remote sensing data, which correlates with the amount of chlorophyll in the vegetation. Given the existing forest classification maps, non-forested regions are masked in the data analysis, so that only forest-related changes in the vegetation are shown in the NDVI image difference products. A combination of two MODIS-bearing satellites, i.e., Terra and Aqua, acquire high temporal and moderate spatial resolution data, enabling the countrywide detection of vegetation changes within a certain observation period. MODIS data are calibrated for setting the pixel quality thresholds, which minimize the artifact of clouds and haze in the analysis. Areas showing dramatic changes are further investigated using higher resolution data, such as ASTER and Landsat 7 ETM. Sequential NDVI products of remote sensing data provide

  13. Response of African humid tropical forests to recent rainfall anomalies

    PubMed Central

    Asefi-Najafabady, Salvi; Saatchi, Sassan

    2013-01-01

    During the last decade, strong negative rainfall anomalies resulting from increased sea surface temperature in the tropical Atlantic have caused extensive droughts in rainforests of western Amazonia, exerting persistent effects on the forest canopy. In contrast, there have been no significant impacts on rainforests of West and Central Africa during the same period, despite large-scale droughts and rainfall anomalies during the same period. Using a combination of rainfall observations from meteorological stations from the Climate Research Unit (CRU; 1950–2009) and satellite observations of the Tropical Rainfall Measuring Mission (TRMM; 1998–2010), we show that West and Central Africa experienced strong negative water deficit (WD) anomalies over the last decade, particularly in 2005, 2006 and 2007. These anomalies were a continuation of an increasing drying trend in the region that started in the 1970s. We monitored the response of forests to extreme rainfall anomalies of the past decade by analysing the microwave scatterometer data from QuickSCAT (1999–2009) sensitive to variations in canopy water content and structure. Unlike in Amazonia, we found no significant impacts of extreme WD events on forests of Central Africa, suggesting potential adaptability of these forests to short-term severe droughts. Only forests near the savanna boundary in West Africa and in fragmented landscapes of the northern Congo Basin responded to extreme droughts with widespread canopy disturbance that lasted only during the period of WD. Time-series analyses of CRU and TRMM data show most regions in Central and West Africa experience seasonal or decadal extreme WDs (less than −600 mm). We hypothesize that the long-term historical extreme WDs with gradual drying trends in the 1970s have increased the adaptability of humid tropical forests in Africa to droughts. PMID:23878335

  14. LiDAR remote sensing observations for forest assessment and recovery responses following disturbance

    NASA Astrophysics Data System (ADS)

    Rosette, J.; Suárez, J.; Fonweben, J.; North, P.

    2013-12-01

    LiDAR data covering 400 km2 in the Cowal and Trossacs Forest District, Scotland, U.K., were used to provide a low cost solution to update the database of public forests and to produce multi-scale cartographic products for supporting management decisions in the event of forest disturbance such as infestation or wind damage. All parameter estimates were directly obtained from the LiDAR data without the necessity of field calibration. This was achieved using a hybrid approach integrating current stand models for Sitka spruce (Picea sitchensis bong. Carr) and LiDAR analysis. More conventional field methods offer percentage sampling, permitting only a proportion of stands to be surveyed each year and aiming to represent stand-level conditions. The use of LiDAR is advantageous in allowing a complete observation-based assessment throughout the forest and greatly-improved spatial representation of important forest parameters. Time-series analysis was performed using LiDAR data collected in the past 10 years. This analysis allowed us to establish growth trajectories in the forest stands, automatically discriminating areas of growth, those whose growth had been affected by disease and the occurrence of windthrow gaps. The results were compared to the cartography produced by the Forest District after a severe wind storm that affected the area in 2012. This analysis showed the ability of LiDAR to create a more precise location and extent of catastrophic damage and windthrow gaps. In addition, once windthrow has occurred, progression of further damage in existing canopy gaps can be observed. This approach additionally allows the impact of disease on forest growth and subsequent recovery response to be monitored.

  15. Monitoring Regional Forest Disturbances across the US with Near Real Time MODIS NDVI Products included in the ForWarn Forest Threat Early Warning System

    NASA Technical Reports Server (NTRS)

    Spruce, Joseph; Hargrove, William W.; Gasser, Gerald; Norman, Steve

    2013-01-01

    U.S. forests occupy approx.1/3 of total land area (approx. 304 million ha). Since 2000, a growing number of regionally evident forest disturbances have occurred due to abiotic and biotic agents. Regional forest disturbances can threaten human life and property, bio-diversity and water supplies. Timely regional forest disturbance monitoring products are needed to aid forest health management work. Near Real Time (NRT) twice daily MODIS NDVI data provide a means to monitor U.S. regional forest disturbances every 8 days. Since 2010, these NRT forest change products have been produced and posted on the US Forest Service ForWarn Early Warning System for Forest Threats.

  16. Interpreting forest biome productivity and cover utilizing nested scales of image resolution and biogeographical analysis

    NASA Technical Reports Server (NTRS)

    Iverson, Louis R.; Cook, Elizabeth A.; Graham, Robin L.; Olson, Jerry S.; Frank, Thomas D.; Ying, KE

    1988-01-01

    The objective was to relate spectral imagery of varying resolution with ground-based data on forest productivity and cover, and to create models to predict regional estimates of forest productivity and cover with a quantifiable degree of accuracy. A three stage approach was outlined. In the first stage, a model was developed relating forest cover or productivity to TM surface reflectance values (TM/FOREST models). The TM/FOREST models were more accurate when biogeographic information regarding the landscape was either used to stratigy the landscape into more homogeneous units or incorporated directly into the TM/FOREST model. In the second stage, AVHRR/FOREST models that predicted forest cover and productivity on the basis of AVHRR band values were developed. The AVHRR/FOREST models had statistical properties similar to or better than those of the TM/FOREST models. In the third stage, the regional predictions were compared with the independent U.S. Forest Service (USFS) data. To do this regional forest cover and forest productivity maps were created using AVHRR scenes and the AVHRR/FOREST models. From the maps the county values of forest productivity and cover were calculated. It is apparent that the landscape has a strong influence on the success of the approach. An approach of using nested scales of imagery in conjunction with ground-based data can be successful in generating regional estimates of variables that are functionally related to some variable a sensor can detect.

  17. Characterization of a forest soil metagenome clone that confers indirubin and indigo production on Escherichia coli.

    PubMed

    Lim, He Kyoung; Chung, Eu Jin; Kim, Jin-Cheol; Choi, Gyung Ja; Jang, Kyoung Soo; Chung, Young Ryun; Cho, Kwang Yun; Lee, Seon-Woo

    2005-12-01

    A microbial community analysis of forest soil from Jindong Valley, Korea, revealed that the most abundant rRNA genes were related to Acidobacteria, a major taxon with few cultured representatives. To access the microbial genetic resources of this forest soil, metagenomic libraries were constructed in fosmids, with an average DNA insert size of more than 35 kb. We constructed 80,500 clones from Yuseong and 33,200 clones from Jindong Valley forest soils. The double-agar-layer method allowed us to select two antibacterial clones by screening the constructed libraries using Bacillus subtilis as a target organism. Several clones produced purple or brown colonies. One of the selected antibacterial clones, pJEC5, produced purple colonies. Structural analysis of the purified pigments demonstrated that the metagenomic clone produced both the pigment indirubin and its isomer, indigo blue, resulting in purple colonies. In vitro mutational and subclonal analyses revealed that two open reading frames (ORFs) are responsible for the pigment production and antibacterial activity. The ORFs encode an oxygenase-like protein and a putative transcriptional regulator. Mutations of the gene encoding the oxygenase canceled both pigment production and antibacterial activity, whereas a subclone carrying the two ORFs retained pigment production and antibacterial activity. This finding suggests that these forest soil microbial genes are responsible for producing the pigment with antibacterial activity. PMID:16332749

  18. 36 CFR 223.278 - Sale of forest botanical products and collection of fees.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... shall be governed under 36 CFR part 223 Subpart G. ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Sale of forest botanical products and collection of fees. 223.278 Section 223.278 Parks, Forests, and Public Property FOREST...

  19. Forests and ozone: productivity, carbon storage, and feedbacks

    PubMed Central

    Wang, Bin; Shugart, Herman H.; Shuman, Jacquelyn K.; Lerdau, Manuel T.

    2016-01-01

    Tropospheric ozone is a serious air-pollutant, with large impacts on plant function. This study demonstrates that tropospheric ozone, although it damages plant metabolism, does not necessarily reduce ecosystem processes such as productivity or carbon sequestration because of diversity change and compensatory processes at the community scale ameliorate negative impacts at the individual level. This study assesses the impact of ozone on forest composition and ecosystem dynamics with an individual-based gap model that includes basic physiology as well as species-specific metabolic properties. Elevated tropospheric ozone leads to no reduction of forest productivity and carbon stock and to increased isoprene emissions, which result from enhanced dominance by isoprene-emitting species (which tolerate ozone stress better than non-emitters). This study suggests that tropospheric ozone may not diminish forest carbon sequestration capacity. This study also suggests that, because of the often positive relationship between isoprene emission and ozone formation, there is a positive feedback loop between forest communities and ozone, which further aggravates ozone pollution. PMID:26899381

  20. Bird response to silviculture induced change in forest structure within bottomland hardwood forests

    USGS Publications Warehouse

    Twedt, D.J.; Somershoe, S.G.

    2008-01-01

    Silvicultural treatments prescribed to encourage development of desired stand structure (i.e., wildlife-forestry) should result in increased abundance of many bird species of management concern, especially species using dense understory habitat. Desired forest conditions within bottomland vary among sites, but average 60-70% overstory canopy that is heterogeneously distributed with >5 dominant trees/ha retained, and a basal area of 14-16 m2/ha. Desired mid-story and understory cover are between 25-40%. Cavity trees (small and large) as well as dead and/or stressed trees should be retained, ultimately providing >14 m3/ha coarse woody debris, and shade-intolerant tree regeneration should be present on 30-40% of the area. We assessed avian response to prescribed wildlife-forestry silviculture treatments via distance-adjusted point counts and constant effort mist-netting within forest stands on Tensas River National Wildlife Refuge in northeastern Louisiana. More species and individuals were detected within stands 1-13 years post-treatment than within untreated stands. Most species, especially species benefiting from disturbance, increased in density after treatment. A few species decreased in density, yet remained fairly relatively abundant post-treatment. Captures from netting suggested three generalized responses to wildlife-forestry silviculture: (1) species with rapid, short-duration positive response, (2) species with slower but more prolonged positive response, and (3) species which initially declined but had long-term positive population response. We recommend increased use of prescribed wildlife-forestry silvicultural prescriptions to enhance bottomland forest habitat for priority bird species.

  1. Decomposition of forest products buried in landfills.

    PubMed

    Wang, Xiaoming; Padgett, Jennifer M; Powell, John S; Barlaz, Morton A

    2013-11-01

    The objective of this study was to investigate the decomposition of selected wood and paper products in landfills. The decomposition of these products under anaerobic landfill conditions results in the generation of biogenic carbon dioxide and methane, while the un-decomposed portion represents a biogenic carbon sink. Information on the decomposition of these municipal waste components is used to estimate national methane emissions inventories, for attribution of carbon storage credits, and to assess the life-cycle greenhouse gas impacts of wood and paper products. Hardwood (HW), softwood (SW), plywood (PW), oriented strand board (OSB), particleboard (PB), medium-density fiberboard (MDF), newsprint (NP), corrugated container (CC) and copy paper (CP) were buried in landfills operated with leachate recirculation, and were excavated after approximately 1.5 and 2.5yr. Samples were analyzed for cellulose (C), hemicellulose (H), lignin (L), volatile solids (VS), and organic carbon (OC). A holocellulose decomposition index (HOD) and carbon storage factor (CSF) were calculated to evaluate the extent of solids decomposition and carbon storage. Samples of OSB made from HW exhibited cellulose plus hemicellulose (C+H) loss of up to 38%, while loss for the other wood types was 0-10% in most samples. The C+H loss was up to 81%, 95% and 96% for NP, CP and CC, respectively. The CSFs for wood and paper samples ranged from 0.34 to 0.47 and 0.02 to 0.27gOCg(-1) dry material, respectively. These results, in general, correlated well with an earlier laboratory-scale study, though NP and CC decomposition measured in this study were higher than previously reported. PMID:23942265

  2. Decomposition of forest products buried in landfills

    SciTech Connect

    Wang, Xiaoming; Padgett, Jennifer M.; Powell, John S.; Barlaz, Morton A.

    2013-11-15

    Highlights: • This study tracked chemical changes of wood and paper in landfills. • A decomposition index was developed to quantify carbohydrate biodegradation. • Newsprint biodegradation as measured here is greater than previous reports. • The field results correlate well with previous laboratory measurements. - Abstract: The objective of this study was to investigate the decomposition of selected wood and paper products in landfills. The decomposition of these products under anaerobic landfill conditions results in the generation of biogenic carbon dioxide and methane, while the un-decomposed portion represents a biogenic carbon sink. Information on the decomposition of these municipal waste components is used to estimate national methane emissions inventories, for attribution of carbon storage credits, and to assess the life-cycle greenhouse gas impacts of wood and paper products. Hardwood (HW), softwood (SW), plywood (PW), oriented strand board (OSB), particleboard (PB), medium-density fiberboard (MDF), newsprint (NP), corrugated container (CC) and copy paper (CP) were buried in landfills operated with leachate recirculation, and were excavated after approximately 1.5 and 2.5 yr. Samples were analyzed for cellulose (C), hemicellulose (H), lignin (L), volatile solids (VS), and organic carbon (OC). A holocellulose decomposition index (HOD) and carbon storage factor (CSF) were calculated to evaluate the extent of solids decomposition and carbon storage. Samples of OSB made from HW exhibited cellulose plus hemicellulose (C + H) loss of up to 38%, while loss for the other wood types was 0–10% in most samples. The C + H loss was up to 81%, 95% and 96% for NP, CP and CC, respectively. The CSFs for wood and paper samples ranged from 0.34 to 0.47 and 0.02 to 0.27 g OC g{sup −1} dry material, respectively. These results, in general, correlated well with an earlier laboratory-scale study, though NP and CC decomposition measured in this study were higher than

  3. Satellite Observation of El Nino Effects on Amazon Forest Phenology and Productivity

    NASA Technical Reports Server (NTRS)

    Asner, Gregory P.; Townsend, Alan R.; Braswell, Bobby H.

    2000-01-01

    Climate variability may affect the functioning of Amazon moist tropical forests, and recent modeling analyses suggest that the carbon dynamics of the region vary interannually in response to precipitation and temperature anomalies. However, due to persistent orbital and atmospheric artifacts in the satellite record, remote sensing observations have not provided quantitative evidence that climate variation affects Amazon forest phenology or productivity, We developed a method to minimize and quantify non-biological artifacts in NOAA AVHRR satellite data, providing a record of estimated forest phenological variation from 1982-1993. The seasonal Normalized Difference Vegetation Index (NDVI) amplitude (a proxy for phenology) increased throughout much of the basin during El Nino periods when rainfall was anomalously low. Wetter La Nina episodes brought consistently smaller NDVI amplitudes. Using radiative transfer and terrestrial biogeochemical models driven by these satellite data, we estimate that canopy-energy absorption and net primary production of Amazon forests varied interannually by as much as 21% and 18%, respectively. These results provide large-scale observational evidence for interannual sensitivity to El Nino of plant phenology and carbon flux in Amazon forests.

  4. When the forest dies: the response of forest soil fungi to a bark beetle-induced tree dieback

    PubMed Central

    Štursová, Martina; Šnajdr, Jaroslav; Cajthaml, Tomáš; Bárta, Jiří; Šantrůčková, Hana; Baldrian, Petr

    2014-01-01

    Coniferous forests cover extensive areas of the boreal and temperate zones. Owing to their primary production and C storage, they have an important role in the global carbon balance. Forest disturbances such as forest fires, windthrows or insect pest outbreaks have a substantial effect on the functioning of these ecosystems. Recent decades have seen an increase in the areas affected by disturbances in both North America and Europe, with indications that this increase is due to both local human activity and global climate change. Here we examine the structural and functional response of the litter and soil microbial community in a Picea abies forest to tree dieback following an invasion of the bark beetle Ips typographus, with a specific focus on the fungal community. The insect-induced disturbance rapidly and profoundly changed vegetation and nutrient availability by killing spruce trees so that the readily available root exudates were replaced by more recalcitrant, polymeric plant biomass components. Owing to the dramatic decrease in photosynthesis, the rate of decomposition processes in the ecosystem decreased as soon as the one-time litter input had been processed. The fungal community showed profound changes, including a decrease in biomass (2.5-fold in the litter and 12-fold in the soil) together with the disappearance of fungi symbiotic with tree roots and a relative increase in saprotrophic taxa. Within the latter group, successive changes reflected the changing availability of needle litter and woody debris. Bacterial biomass appeared to be either unaffected or increased after the disturbance, resulting in a substantial increase in the bacterial/fungal biomass ratio. PMID:24671082

  5. When the forest dies: the response of forest soil fungi to a bark beetle-induced tree dieback.

    PubMed

    Stursová, Martina; Snajdr, Jaroslav; Cajthaml, Tomáš; Bárta, Jiří; Santrůčková, Hana; Baldrian, Petr

    2014-09-01

    Coniferous forests cover extensive areas of the boreal and temperate zones. Owing to their primary production and C storage, they have an important role in the global carbon balance. Forest disturbances such as forest fires, windthrows or insect pest outbreaks have a substantial effect on the functioning of these ecosystems. Recent decades have seen an increase in the areas affected by disturbances in both North America and Europe, with indications that this increase is due to both local human activity and global climate change. Here we examine the structural and functional response of the litter and soil microbial community in a Picea abies forest to tree dieback following an invasion of the bark beetle Ips typographus, with a specific focus on the fungal community. The insect-induced disturbance rapidly and profoundly changed vegetation and nutrient availability by killing spruce trees so that the readily available root exudates were replaced by more recalcitrant, polymeric plant biomass components. Owing to the dramatic decrease in photosynthesis, the rate of decomposition processes in the ecosystem decreased as soon as the one-time litter input had been processed. The fungal community showed profound changes, including a decrease in biomass (2.5-fold in the litter and 12-fold in the soil) together with the disappearance of fungi symbiotic with tree roots and a relative increase in saprotrophic taxa. Within the latter group, successive changes reflected the changing availability of needle litter and woody debris. Bacterial biomass appeared to be either unaffected or increased after the disturbance, resulting in a substantial increase in the bacterial/fungal biomass ratio. PMID:24671082

  6. Changes in Forest Production, Biomass and Carbon: Results From the 2015 UN FAO Global Forest Resource Assessment

    NASA Astrophysics Data System (ADS)

    Navar, J.

    2015-12-01

    Forests are important sources of livelihoods to millions of people and contribute to national economic development of many countries. In addition, they are vital sources and sinks of carbon and contribute to the rate of climate change. The UN Food and Agriculture Organization has been collecting and presenting data on global forest resources and forest cover since 1948. This paper builds on data from FAO's 2015 Global Forest Resource Assessment (FRA) and presents information on growing stock, biomass, carbon stock, wood removals, and changes of forest area primarily designated for production and multiple use of the world's forests. Between 1990 and 2015, the total growing stock volume has increased in East Asia, Caribbean, Western and Central Asia, North America, Europe (including the Russian Federation), and Oceania with the highest relative increase in East Asia and the Caribbean. In all other subregions the total growing stock volume decreased. North and Central America, Europe and Asia report forest C stock increases while South America and Africa report strong decreases and Oceania reports stable forest C stocks. The annual rate of decrease of forest C stock weakened between 1990 and 2015. The total volume of annual wood removals including wood fuel removals increased between 1990 and 2011, but shows a remarkable decline during the 2008-2009 economic crisis. Forest areas designated for production purposes differ considerably between subregions. The percentage of production area out of total forest area ranges between 16 percent in South America and 53 percent in Europe. Globally about one quarter of the forest area is designated to multiple use forestry. The balance between biomass growth and removals shows considerable sub-regional differences and related implications for the sustainable use of forests.

  7. Forest products: Fiber loading for paper manufacturing

    SciTech Connect

    1999-09-29

    Fact sheet on manufacturing filler during paper manufacturing written for the NICE3 Program. With its new fiber loading process, Voith Sulzer, Inc., is greatly improving the efficiency of paper production and recycling. Fiber loading produces precipitated calcium carbonate (PCC) filler in the pulp recycling process at costs below conventional means. Fiber loading allows papermakers to use as much filler, like PCC, as possible because it costs 80% less than fiber. In addition, increased filler and fines retention due to fiber loading reduces the quantity of greenhouse gas emissions, deinking sludge, and other waste while substantially lowering energy costs. Currently, the most efficient way to produce PCC as filler is to make it in a satellite plant adjacent to a paper mill. Satellite plants exist near large scale paper mills (producing 700 tons per day) because the demand at large mills justifies building a costly ($15 million, average) satellite plant. This new fiber loading process combines the PCC manufacturing technology used in a satellite plant with the pulp processing operations of a paper mill. It is 33% less expensive to augment an existing paper mill with fiber loading technology than to build a satellite plant for the same purpose. This technology is applicable to the manufacturing of all printing and writing paper, regardless of the size or capacity of the paper mill.

  8. Will Elevated CO2 Increase Forest Productivity? Evidence from an Australian FACE Experiment

    NASA Astrophysics Data System (ADS)

    Collins, L.

    2015-12-01

    Rising atmospheric CO2 may enhance forest productivity via CO2 fertilisation and increased soil moisture associated with water savings. Quantification of the response of forest productivity to rising CO2 concentrations is important, as increased forest productivity may contribute to the mitigation of anthropogenic climate change. Vegetation greenness indices derived from digital photographs have been correlated with a number of measures of ecosystem productivity including total biomass, leaf area index and gross primary productivity. Our study examines the effect of elevated CO2 on patterns in overstorey and understorey vegetation greenness at a Free Air CO2 Enrichment facility (EucFACE) situated within a temperate eucalypt forest in Sydney, Australia. EucFACE consists of six treatment areas, three subjected to ambient CO2 ('ambient') and three with ambient plus 150 ppm CO2 ('elevated'). Each treatment area had one camera monitoring canopy greenness for a 12 month period and four cameras monitoring one understorey vegetation plot (2.25 m2) each for a 15 month period. Vegetation greenness was measured daily using the green chromatic coordinate (GCC). Understorey and overstorey GCC and rates of understorey greening and browning were not affected by elevated CO2. Periodic differences in canopy greening and browning between CO2 treatments were observed, though these probably reflect an insect defoliation event in one treatment area. Increases in canopy and understorey GCC were associated with a combination of extended periods of high soil volumetric water content (VWC) (>0.1) and high maximum temperatures (>25 °C). Browning appeared to be associated with a combination of periods of high maximum temperatures and low VWC or low minimum temperatures. Our short term findings suggest that eucalypt forest productivity will be sensitive to changes in climate, but may be relatively insensitive to changes in CO2 in the near future.

  9. Divergent phenological response to hydroclimate variability in forested mountain watersheds.

    PubMed

    Hwang, Taehee; Band, Lawrence E; Miniat, Chelcy F; Song, Conghe; Bolstad, Paul V; Vose, James M; Love, Jason P

    2014-08-01

    Mountain watersheds are primary sources of freshwater, carbon sequestration, and other ecosystem services. There is significant interest in the effects of climate change and variability on these processes over short to long time scales. Much of the impact of hydroclimate variability in forest ecosystems is manifested in vegetation dynamics in space and time. In steep terrain, leaf phenology responds to topoclimate in complex ways, and can produce specific and measurable shifts in landscape forest patterns. The onset of spring is usually delayed at a specific rate with increasing elevation (often called Hopkins' Law; Hopkins, 1918), reflecting the dominant controls of temperature on greenup timing. Contrary with greenup, leaf senescence shows inconsistent trends along elevation gradients. Here, we present mechanisms and an explanation for this variability and its significance for ecosystem patterns and services in response to climate. We use moderate-resolution imaging spectro-radiometer (MODIS) Normalized Difference Vegetation Index (NDVI) data to derive landscape-induced phenological patterns over topoclimate gradients in a humid temperate broadleaf forest in southern Appalachians. These phenological patterns are validated with different sets of field observations. Our data demonstrate that divergent behavior of leaf senescence with elevation is closely related to late growing season hydroclimate variability in temperature and water balance patterns. Specifically, a drier late growing season is associated with earlier leaf senescence at low elevation than at middle elevation. The effect of drought stress on vegetation senescence timing also leads to tighter coupling between growing season length and ecosystem water use estimated from observed precipitation and runoff generation. This study indicates increased late growing season drought may be leading to divergent ecosystem response between high and low elevation forests. Landscape-induced phenological patterns

  10. Operational Application of Envisat ASAR in Tropical Production Forest

    NASA Astrophysics Data System (ADS)

    Raimadoya, M.; Trisasongko, B.

    2003-04-01

    A joint research between European Space Agency (ESA) and Bogor Agricultural University (IPB), Indonesia, has been approved under Envisat AO (AO-ID 869). The research is intended to study the operational application of Advanced Synthetic-Aperture Radar (ASAR) for production forest management in Indonesia. Two test sites in forest plantation area of PT Riau Andalan Pulp and Paper (Riaupulp) in Riau Province, Central Sumatera, Indonesia, have been selected recently for the implementation of this joint research. This paper briefs the recent progress of this two-year research (2002-2004) activity. The main objective is to explore the potential of ASAR image analysis application, including POLINSAR, for better and more efficient operational management of tropical plantation forest and its environment. Several interesting operational applications have been identified for the test sites. First application is vegetative cover classification of Acacias, mixed hardwoods, shrubs, oil palms and bare lands. The second is biomass-related application, which study Envisat data on biomass monitoring related to forest plantation. The third is environmental study particularly for site degradation, including issues on monitoring of water bodies and burn site.

  11. Impact of climate change on forests, forest products and the carbon cycle in the Congo Basin.

    NASA Astrophysics Data System (ADS)

    Kruijt, Bart; Jans, Wilma; Franssen, Wietse; Ludwig, Fulco

    2014-05-01

    Africa is widely seen as the continent most vulnerable to climate change. Current climate variability already has a large impact on the economies of developing countries. Large parts of African economies are highly climate sensitive, in particular agriculture, infrastructure and water sector. In this study we performed an analysis of climate change impacts in the Congo Basin on Forest ecosystem functioning and carbon storage. We emphasise the methodologies and validation involved in modelling the basin-wide carbon budgets. We also studied the potential shifts in broad classes of vegetation types, resulting from climate change. Finally, we compared annual productivity of the Congo forests with statistics of wood fuel and charcoal use for each of the countries in the region. The model simulations suggest that the region's forests will see increasing productivity under future climate, however, the effect of rising CO2 concentrations, stimulating growth, is highly uncertain. From these findings it follows that the potential in the region to implement UNFCCC-REDD+ projects is still very uncertain, but probably sustainable and feasible. The analysis shows that, averaged over 10 years, wood fuel and charcoal use amount to 50% and in some countries up to 100% or even more of the yearly vegetation carbon increase. These percentages generally increases with population density.

  12. Under What Circumstances Do Wood Products from Native Forests Benefit Climate Change Mitigation?

    PubMed Central

    Keith, Heather; Lindenmayer, David; Macintosh, Andrew; Mackey, Brendan

    2015-01-01

    Climate change mitigation benefits from the land sector are not being fully realised because of uncertainty and controversy about the role of native forest management. The dominant policy view, as stated in the IPCC’s Fifth Assessment Report, is that sustainable forest harvesting yielding wood products, generates the largest mitigation benefit. We demonstrate that changing native forest management from commercial harvesting to conservation can make an important contribution to mitigation. Conservation of native forests results in an immediate and substantial reduction in net emissions relative to a reference case of commercial harvesting. We calibrated models to simulate scenarios of native forest management for two Australian case studies: mixed-eucalypt in New South Wales and Mountain Ash in Victoria. Carbon stocks in the harvested forest included forest biomass, wood and paper products, waste in landfill, and bioenergy that substituted for fossil fuel energy. The conservation forest included forest biomass, and subtracted stocks for the foregone products that were substituted by non-wood products or plantation products. Total carbon stocks were lower in harvested forest than in conservation forest in both case studies over the 100-year simulation period. We tested a range of potential parameter values reported in the literature: none could increase the combined carbon stock in products, slash, landfill and substitution sufficiently to exceed the increase in carbon stock due to changing management of native forest to conservation. The key parameters determining carbon stock change under different forest management scenarios are those affecting accumulation of carbon in forest biomass, rather than parameters affecting transfers among wood products. This analysis helps prioritise mitigation activities to focus on maximising forest biomass. International forest-related policies, including negotiations under the UNFCCC, have failed to recognize fully the mitigation

  13. Under What Circumstances Do Wood Products from Native Forests Benefit Climate Change Mitigation?

    PubMed

    Keith, Heather; Lindenmayer, David; Macintosh, Andrew; Mackey, Brendan

    2015-01-01

    Climate change mitigation benefits from the land sector are not being fully realised because of uncertainty and controversy about the role of native forest management. The dominant policy view, as stated in the IPCC's Fifth Assessment Report, is that sustainable forest harvesting yielding wood products, generates the largest mitigation benefit. We demonstrate that changing native forest management from commercial harvesting to conservation can make an important contribution to mitigation. Conservation of native forests results in an immediate and substantial reduction in net emissions relative to a reference case of commercial harvesting. We calibrated models to simulate scenarios of native forest management for two Australian case studies: mixed-eucalypt in New South Wales and Mountain Ash in Victoria. Carbon stocks in the harvested forest included forest biomass, wood and paper products, waste in landfill, and bioenergy that substituted for fossil fuel energy. The conservation forest included forest biomass, and subtracted stocks for the foregone products that were substituted by non-wood products or plantation products. Total carbon stocks were lower in harvested forest than in conservation forest in both case studies over the 100-year simulation period. We tested a range of potential parameter values reported in the literature: none could increase the combined carbon stock in products, slash, landfill and substitution sufficiently to exceed the increase in carbon stock due to changing management of native forest to conservation. The key parameters determining carbon stock change under different forest management scenarios are those affecting accumulation of carbon in forest biomass, rather than parameters affecting transfers among wood products. This analysis helps prioritise mitigation activities to focus on maximising forest biomass. International forest-related policies, including negotiations under the UNFCCC, have failed to recognize fully the mitigation

  14. Wisconsin timber industry: An assessment of timber product output and use, 1994. Forest Service resource bulletin

    SciTech Connect

    Hackett, R.L.; Whipple, J.W.

    1997-09-21

    In this bulletin we discuss recent Wisconsin forest industry trends and report the results of a detailed study of forest indsutry, industrial roundwood production, and associated primary mill wood and bark residue in Wisconsin in 1994. Such detailed information is necessary for intelligent planning and decisionmaking in wood procurement, forest resource management, and forest industry development. Likewise, researchers need current forest industry and idustrial roundwood information for planning project.

  15. Minnesota timber industry. An assessment of timber product output and use, 1992. Forest Service resource bulletin

    SciTech Connect

    Hackett, R.L.; Dahlman, R.A.

    1997-09-19

    In this bulletin, the authors discuss recent Minnesota forest industry trends and report the results of a detailed study of forest industrial roundwood production, and associated primary mill wood and bark residue in Minnesota in 1992. Such detailed information is necessary for intelligent planning and decisionmaking in wood procurement, forest resource management, and forest industry development. Likewise, researchers need current forest industry and industrial roundwood information for planning projects.

  16. Minnesota timber industry: An assessment of timber product output and use, 1990. Forest Service resource bulletin

    SciTech Connect

    Hackett, R.L.; Dahlman, R.A.

    1993-01-01

    The bulletin includes recent Minnesota forest industry trends and report the results of a detailed study of forest industry, industrial roundwood production, and associated primary mill wood and bark residue in Minnesota in 1990. Such detailed information is necessary for intelligent planning and decisionmaking in wood procurement, forest resource management, and forest industry development. Likewise, researchers need current forest industry and industrial roundwood information for planning projects.

  17. Forest responses to increasing aridity and warmth in the southwestern United States

    PubMed Central

    Williams, A. Park; Allen, Craig D.; Millar, Constance I.; Swetnam, Thomas W.; Michaelsen, Joel; Still, Christopher J.; Leavitt, Steven W.

    2010-01-01

    In recent decades, intense droughts, insect outbreaks, and wildfires have led to decreasing tree growth and increasing mortality in many temperate forests. We compared annual tree-ring width data from 1,097 populations in the coterminous United States to climate data and evaluated site-specific tree responses to climate variations throughout the 20th century. For each population, we developed a climate-driven growth equation by using climate records to predict annual ring widths. Forests within the southwestern United States appear particularly sensitive to drought and warmth. We input 21st century climate projections to the equations to predict growth responses. Our results suggest that if temperature and aridity rise as they are projected to, southwestern trees will experience substantially reduced growth during this century. As tree growth declines, mortality rates may increase at many sites. Increases in wildfires and bark-beetle outbreaks in the most recent decade are likely related to extreme drought and high temperatures during this period. Using satellite imagery and aerial survey data, we conservatively calculate that ≈2.7% of southwestern forest and woodland area experienced substantial mortality due to wildfires from 1984 to 2006, and ≈7.6% experienced mortality associated with bark beetles from 1997 to 2008. We estimate that up to ≈18% of southwestern forest area (excluding woodlands) experienced mortality due to bark beetles or wildfire during this period. Expected climatic changes will alter future forest productivity, disturbance regimes, and species ranges throughout the Southwest. Emerging knowledge of these impending transitions informs efforts to adaptively manage southwestern forests. PMID:21149715

  18. Forest responses to increasing aridity and warmth in the southwestern United States

    USGS Publications Warehouse

    Williams, A.P.; Allen, C.D.; Millar, C.I.; Swetnam, T.W.; Michaelsen, J.; Still, C.J.; Leavitt, Steven W.

    2010-01-01

    In recent decades, intense droughts, insect outbreaks, and wildfires have led to decreasing tree growth and increasingmortality inmany temperate forests. We compared annual tree-ring width data from 1,097 populations in the coterminous United States to climate data and evaluated site-specific tree responses to climate variations throughout the 20th century. For each population, we developed a climate-driven growth equation by using climate records to predict annual ring widths. Forests within the southwestern United States appear particularly sensitive to drought and warmth.We input 21st century climate projections to the equations to predict growth responses. Our results suggest that if temperature and aridity rise as they are projected to, southwestern trees will experience substantially reduced growth during this century. As tree growth declines, mortality rates may increase at many sites. Increases in wildfires and bark-beetle outbreaks in the most recent decade are likely related to extreme drought and high temperatures during this period. Using satellite imagery and aerial survey data, we conservatively calculate that ???2.7% of southwestern forest and woodland area experienced substantialmortality due to wildfires from1984 to 2006, and???7. 6%experiencedmortality associated with bark beetles from 1997 to 2008. We estimate that up to ???18% of southwestern forest area (excluding woodlands) experienced mortality due to bark beetles or wildfire during this period. Expected climatic changes will alter future forest productivity, disturbance regimes, and species ranges throughout the Southwest. Emerging knowledge of these impending transitions informs efforts to adaptively manage southwestern forests.

  19. Aerosol Production in a Mixed Deciduous/Coniferous Forest

    NASA Astrophysics Data System (ADS)

    Slade, N.; Mielke, L.; Alaghmand, M.; Galloway, M.; Kammrath, A.; Keutsch, F.; Hansen, R.; Griffith, S.; Dusanter, S.; Stevens, P.; Carroll, M.; Bertman, S.; Shepson, P.

    2008-12-01

    Aerosols are of fundamental concern because of their impacts on air quality, human health and radiative forcing. Recent studies have focused on secondary organic aerosol (SOA) production due to oxidation of volatile organic compounds (VOCs), and more importantly biogenic-VOCs (BVOCs), in particular, isoprene. However, the SOA precursors are not well understood because the mechanisms have shown that isoprene oxidation can contribute to aerosol production through multiple generation oxidation products. For terpenes, it is more likely that primary or secondary oxidation products lead to particle formation. In the present study, we measured the aerosol size distribution, along with O3, HOx, NOx, NOy and BVOCs, in a mixed deciduous forest that is undergoing successional transition to a conifer-dominated species mix. This study was conducted in a rural forest environment in northern Michigan as a part of the summer 2008 PROPHET campaign at the University of Michigan Biological Station (UMBS). We examine here the potential BVOC contribution to aerosol formation. A TSI, inc. Scanning Mobility Particle Sizer (SMPS) was used to measure aerosol number density in the size range, 15 nm < x < 711 nm and a Proton Transfer Reaction - Linear Ion Trap (PTR-LIT) mass spectrometer for quantifying isoprene and other BVOCs, including methyl vinyl ketone and methacrolein, and total monoterpenes. Preliminary results show periods of new particle production. Here we use a unique set of BVOC, HOx, NOx, NOy, O3 and meteorological data to examine conditions leading to new particle production.

  20. Productivity of Northern Eurasian forests: Analysis of uncertainties

    NASA Astrophysics Data System (ADS)

    Shvidenko, Anatoly; Schepaschenko, Dmitry; McCallum, Ian

    2010-05-01

    Indicators of biological productivity of forests (live and dead biomass, net primary production, net and gross growth) are crucial for both assessment of the impacts of terrestrial ecosystems on major biogeochemical cycles and practice of sustainable forest management. However, different information and the diversity of methods used in the assessments of forests productivity cause substantial variation in reported estimates. The paper contains a systems analysis of the existing methods, their uncertainties, and a description of available information. With respect to Northern Eurasian forests, the major reasons for uncertainties could be categorized as following: (1) significant biases that are inherent in a number of important sources of available information (e.g., forest inventory data, results of measurements of some indicators in situ); (2) inadequacy and oversimplification of models of different types (empirical aggregations, process-based models); (3) lack of data for some regions; and (4) upscaling procedure of 'point' observations. Based on as comprehensive as possible adherence to the principles of systems analysis, we made an attempt to provide a reanalysis of indicators of forests productivity of Russia aiming at obtaining the results for which uncertainties could be estimated in a reliable and transparent way. Within a landscape-ecosystem approach it has required (1) development of an expert system for refinement of initial data including elimination of recognized biases; (2) delineation of ecological regions based on gradients of major indicators of productivity; (3) transition to multidimensional models (e.g., for calculation of spatially distributed biomass expansion factors); (4) use of process-based elements in empirical models; and (5) development of some approaches which presumably do not have recognized biases. However, taking into account the fuzzy character of the problem, the above approach (as well as any other individually used method) is

  1. 3 CFR 8442 - Proclamation 8442 of October 23, 2009. National Forest Products Week, 2009

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Forest Products Week, 2009 8442 Proclamation 8442 Presidential Documents Proclamations Proclamation 8442 of October 23, 2009 Proc. 8442 National Forest Products Week, 2009By the President of the United States of America A Proclamation America’s forests have helped spur the growth and development that...

  2. 25 CFR 163.19 - Contracts for the sale of forest products.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Contracts for the sale of forest products. 163.19 Section 163.19 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.19 Contracts for the sale of forest products. (a) In...

  3. 25 CFR 163.19 - Contracts for the sale of forest products.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Contracts for the sale of forest products. 163.19 Section 163.19 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.19 Contracts for the sale of forest products. (a) In...

  4. 25 CFR 163.19 - Contracts for the sale of forest products.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Contracts for the sale of forest products. 163.19 Section 163.19 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.19 Contracts for the sale of forest products. (a) In...

  5. 25 CFR 163.19 - Contracts for the sale of forest products.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Contracts for the sale of forest products. 163.19 Section 163.19 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forest Management and Operations § 163.19 Contracts for the sale of forest products. (a) In...

  6. Forest floor vegetation response to nitrogen deposition in Europe.

    PubMed

    Dirnböck, Thomas; Grandin, Ulf; Bernhardt-Römermann, Markus; Beudert, Burkhardt; Canullo, Roberto; Forsius, Martin; Grabner, Maria-Theresia; Holmberg, Maria; Kleemola, Sirpa; Lundin, Lars; Mirtl, Michael; Neumann, Markus; Pompei, Enrico; Salemaa, Maija; Starlinger, Franz; Staszewski, Tomasz; Uziębło, Aldona Katarzyna

    2014-02-01

    Chronic nitrogen (N) deposition is a threat to biodiversity that results from the eutrophication of ecosystems. We studied long-term monitoring data from 28 forest sites with a total of 1,335 permanent forest floor vegetation plots from northern Fennoscandia to southern Italy to analyse temporal trends in vascular plant species cover and diversity. We found that the cover of plant species which prefer nutrient-poor soils (oligotrophic species) decreased the more the measured N deposition exceeded the empirical critical load (CL) for eutrophication effects (P = 0.002). Although species preferring nutrient-rich sites (eutrophic species) did not experience a significantly increase in cover (P = 0.440), in comparison to oligotrophic species they had a marginally higher proportion among new occurring species (P = 0.091). The observed gradual replacement of oligotrophic species by eutrophic species as a response to N deposition seems to be a general pattern, as it was consistent on the European scale. Contrary to species cover changes, neither the decrease in species richness nor of homogeneity correlated with nitrogen CL exceedance (ExCLemp N). We assume that the lack of diversity changes resulted from the restricted time period of our observations. Although existing habitat-specific empirical CL still hold some uncertainty, we exemplify that they are useful indicators for the sensitivity of forest floor vegetation to N deposition. PMID:24132996

  7. Landscape and plant physiological controls on water dynamics and forest productivity within a watershed

    NASA Astrophysics Data System (ADS)

    Hu, Jia; Jencso, Kelsey; Looker, Nathaniel; Martin, Justin; Hoylman, Zachary

    2015-04-01

    Across the Western U.S., declining snowpacks have resulted in increased water limitation, leading to reduced productivity in high elevation forests. While our current understanding of how forests respond to climate change is typically focused on measuring/modeling the physiological responses and climate feedbacks, our study aims to combine physiology with hydrology to examine how landscape topography modulates the sensitivity of forests to climate. In a forested watershed in Western Montana, we linked climate variability to the physical watershed characteristics and the physiological response of vegetation to examine forest transpiration and productivity rates. Across the entire watershed, we found a strong relationship between productivity and the topographic wetness index, a proxy for soil moisture storage. However, this relationship was highly dependent on the intensity of solar radiation, suggesting that at high elevations productivity was limited by temperature, while at low elevations productivity was limited by moisture. In order to identify the mechanisms responsible for this relationship, we then examined how different coniferous species respond to changing environmental and hydrologic regimes. We first examined transpiration and productivity rates at the hillslope scale at four plots, ranging in elevation and aspect across the watershed. We found trees growing in the hollows had higher transpiration and productivity rates than trees growing in the side slope, but that these differences were more pronounced at lower elevations. We then used oxygen isotope to examine water source use by different species across the watershed. We found that trees growing in the hollows used snowmelt for a longer period. This was most likely due to upslope subsidies of snowmelt water to the hollow areas. However, we found that trees growing at lower elevations used proportionally more snowmelt than trees at the higher elevations. This was most likely due to the trees at lower

  8. Soil responses to management, increased precipitation, and added nitrogen in ponderosa pine forests.

    PubMed

    Hungate, Bruce A; Hart, Stephen C; Selmants, Paul C; Boyle, Sarah I; Gehring, Catherine A

    2007-07-01

    Forest management, climatic change, and atmospheric N deposition can affect soil biogeochemistry, but their combined effects are not well understood. We examined the effects of water and N amendments and forest thinning and burning on soil N pools and fluxes in ponderosa pine forests near Flagstaff, Arizona (USA). Using a 15N-depleted fertilizer, we also documented the distribution of added N into soil N pools. Because thinning and burning can increase soil water content and N availability, we hypothesized that these changes would alleviate water and N limitation of soil processes, causing smaller responses to added N and water in the restored stand. We found little support for this hypothesis. Responses of fine root biomass, potential net N mineralization, and the soil microbial N to water and N amendments were mostly unaffected by stand management. Most of the soil processes we examined were limited by N and water, and the increased N and soil water availability caused by forest restoration was insufficient to alleviate these limitations. For example, N addition caused a larger increase in potential net nitrification in the restored stand, and at a given level of soil N availability, N addition had a larger effect on soil microbial N in the restored stand. Possibly, forest restoration increased the availability of some other limiting resource, amplifying responses to added N and water. Tracer N recoveries in roots and in the forest floor were lower in the restored stand. Natural abundance delta15N of labile soil N pools were higher in the restored stand, consistent with a more open N cycle. We conclude that thinning and burning open up the N cycle, at least in the short-term, and that these changes are amplified by enhanced precipitation and N additions. Our results suggest that thinning and burning in ponderosa pine forests will not increase their resistance to changes in soil N dynamics resulting from increased atmospheric N deposition or increased

  9. Soil Biochemical Responses to Nitrogen Addition in a Bamboo Forest

    PubMed Central

    Tu, Li-hua; Chen, Gang; Peng, Yong; Hu, Hong-ling; Hu, Ting-xing; Zhang, Jian; Li, Xian-wei; Liu, Li; Tang, Yi

    2014-01-01

    Many vital ecosystem processes take place in the soils and are greatly affected by the increasing active nitrogen (N) deposition observed globally. Nitrogen deposition generally affects ecosystem processes through the changes in soil biochemical properties such as soil nutrient availability, microbial properties and enzyme activities. In order to evaluate the soil biochemical responses to elevated atmospheric N deposition in bamboo forest ecosystems, a two-year field N addition experiment in a hybrid bamboo (Bambusa pervariabilis × Dendrocalamopsis daii) plantation was conducted. Four levels of N treatment were applied: (1) control (CK, without N added), (2) low-nitrogen (LN, 50 kg N ha−1 year−1), (3) medium-nitrogen (MN, 150 kg N ha−1 year−1), and (4) high-nitrogen (HN, 300 kg N ha−1 year−1). Results indicated that N addition significantly increased the concentrations of NH4+, NO3−, microbial biomass carbon, microbial biomass N, the rates of nitrification and denitrification; significantly decreased soil pH and the concentration of available phosphorus, and had no effect on the total organic carbon and total N concentration in the 0–20 cm soil depth. Nitrogen addition significantly stimulated activities of hydrolytic enzyme that acquiring N (urease) and phosphorus (acid phosphatase) and depressed the oxidative enzymes (phenol oxidase, peroxidase and catalase) activities. Results suggest that (1) this bamboo forest ecosystem is moving towards being limited by P or co-limited by P under elevated N deposition, (2) the expected progressive increases in N deposition may have a potential important effect on forest litter decomposition due to the interaction of inorganic N and oxidative enzyme activities, in such bamboo forests under high levels of ambient N deposition. PMID:25029346

  10. 76 FR 50715 - Information Collection; Forest Products Removal Permits and Contracts

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-16

    ...In accordance with the Paperwork Reduction Act of 1995, the Forest Service is seeking comments from all interested individuals and organizations on the extension with no revision of a currently approved information collection, Forest Products Removal Permits and...

  11. Redox potential: An indicator of site productivity in forest management

    NASA Astrophysics Data System (ADS)

    Sajedi, Toktam; Prescott, Cindy; Lavkulich, Les

    2010-05-01

    Redox potential (Eh) is an integrated soil measurement that reflects several environmental conditions in the soil associated with aeration, moisture and carbon (organic matter) dynamics. Its measurement can be related to water table fluctuations, precipitation and landscape gradients, organic matter decomposition rates, nutrient dynamics, biological diversity and plant species distribution. Redox is an excellent indicator of soil biological processes, as it is largely a reflection of microbial activities which to a large extent govern carbon dynamics and nutrient cycling. Redox thus serves as an ecological indicator of site productivity at the ecosystem scale and may be used for management purposes as its magnitude can be altered by activities such as harvesting and drainage. A threshold value of 300 mv has been documented as the critical value below which anaerobic conditions in the soil develop. However, redox measurements and its impacts on ecosystem processes such as nutrient cycling and productivity, especially in forest ecosystems, have not received the attention that this "master" variable deserves, On northern Vancouver Island, Canada, regenerating stands of western redcedar-western hemlock (CH) sites exhibit symptoms of nutrient deficiencies and slow growth, but this phenomenon does not occur on adjacent western hemlock- amabalis fir (HA) sites. We tested the hypothesis that differences in nutrient supply and distribution of plant species was caused by differences in moisture regime and redox potential. Redox potential, pH, soil aeration depth (steel rods), organic matter thickness, bulk density, soil carbon store, plant species distribution and richness were measured at five old-growth and five 10-year-old cutover blocks. Results of investigations confirmed that CH forests were wetter, had redox values lower than the critical 300mv and a shallower aerated zone, compared with adjacent regenerating HA sites. Fifty percent of the CH plots had redox values

  12. Multidisciplinary Research on Canopy Photosynthetic Productivity in a Cool-Temperate Deciduous Broadleaf Forest in Japan

    NASA Astrophysics Data System (ADS)

    Muraoka, H.; Noda, H. M.; Saitoh, T. M.; Nagai, S.

    2014-12-01

    Forest canopy has crucial roles in regulating energy and material exchange between the atmosphere and terrestrial ecosystems and in ecological processes with respect to carbon cycle and growth in the ecosystems. Challenges to the canopy of tall forests for such research involve the access to the leaves for ecophysiological observations, responses of leaves to the changing environments from seconds to years, and up-scaling the leaf-level phenomena to canopy and landscape-levels. A long-term, multidisciplinary approach has been conducted in a cool-temperate deciduous broadleaf forest in Takayama site (ca. 1400m a.s.l.) in central Japan. This forest canopy is dominated by Quercus crispula and Betula ermanii. We have been focusing on the phenology of photosynthetic productivity from a single leaf to canopy, and to landscape level, by combining leaf ecophysiological research, optical observations by spectroradiometers and time-laps cameras with the aid of "Phenological Eyes Network (PEN)", and process-based modellings. The canopy-level photosynthesis is then compared with the micrometeorolgical observation of CO2 flux at the site. So far we have been clarifying that (1) inter-annual variations in seasonal growth rate and senescence rate of leaf photosynthetic capacity and canopy leaf area are largely responsible for the inter-annual change in forest photosynthesis, and (2) spectral vegetation indices such as enhanced vegetation index (EVI) and chlorophyll index (CCI) can be the indicator to observe the phenology of forest canopy photosynthesis. In addition to these efforts since 2003, we established an open-field warming experiment on the branches of the canopy trees, to investigate the possible influence of temperature increase on leaf photosynthetic and optical properties and then to examine whether the optical satellite remote sensing can detect the changes in photosynthetic capacity and phenology by ongoing global warming.

  13. Life-history traits and landscape characteristics predict macro-moth responses to forest fragmentation.

    PubMed

    Slade, Eleanor M; Merckx, Thomas; Riutta, Terhi; Bebber, Daniel P; Redhead, David; Riordan, Philip; Macdonald, David W

    2013-07-01

    How best to manage forest patches, mitigate the consequences of forest fragmentation, and enable landscape permeability are key questions facing conservation scientists and managers. Many temperate forests have become increasingly fragmented, resulting in reduced interior forest habitat, increased edge habitats, and reduced connectivity. Using a citizen science landscape-scale mark-release-recapture study on 87 macro-moth species, we investigated how both life-history traits and landscape characteristics predicted macro-moth responses to forest fragmentation. Wingspan, wing shape, adult feeding, and larval feeding guild predicted macro-moth mobility, although the predictive power of wingspan and wing shape depended on the species' affinity to the forest. Solitary trees and small fragments functioned as "stepping stones," especially when their landscape connectivity was increased, by being positioned within hedgerows or within a favorable matrix. Mobile forest specialists were most affected by forest fragmentation: despite their high intrinsic dispersal capability, these species were confined mostly to the largest of the forest patches due to their strong affinity for the forest habitat, and were also heavily dependent on forest connectivity in order to cross the agricultural matrix. Forest fragments need to be larger than five hectares and to have interior forest more than 100 m from the edge in order to sustain populations of forest specialists. Our study provides new insights into the movement patterns of a functionally important insect group, with implications for the landscape-scale management of forest patches within agricultural landscapes. PMID:23951712

  14. Examining the effects of forest thinning on runoff responses at different catchments scales in forested headwaters

    NASA Astrophysics Data System (ADS)

    Dung, B. X.; Gomi, T.; Onda, Y.; Kato, H.; Hiraoka, M.

    2012-12-01

    We conducted field observation in nested headwater catchments draining Japanese cypress (Chamaecyparis obtusa) and cedar (Cryptomeria japonica) forests at Tochigi prefectures for examining the effects of forest thinning on runoff generation at different catchment scales. 50% of the stems was removed with line thinning in catchment K2 (treatment catchment), while catchment K3 remained untreated as a control. We also monitored nested catchments within K2-1 (17.1 ha) as K2-2 (10.2 ha), K2-3 (3.7 ha) and K2-4 (5.1 ha), and within K3-1 (8.9 ha) as K3-2 (3.0 ha). Runoff from the catchments was monitored during the pre-thinning (from April, 2010 to May 2011), and the post-thinning periods (from June 2011 to July 2012). Paired-catchment and hydrograph separation analysis were used to evaluate the effects of forest thinning on runoff generation at different catchment scales. We developed the pre-thinning calibration equation for predicting post-thinning responses. Paired-catchment analysis revealed that annual catchment runoff increased 648 mm in K2-1, 414 mm in K2-2, 517 mm in K2-3 and 487 mm in K2-4 after the thinning. Both quick and delayed runoff components only increased significantly in the larger catchments of K2-1 and K2-2, while only delayed runoff components of smaller catchments (K2-3 and K2-4) increased significantly during the post-thinning period. Increases of quick runoff in large catchments could be associated with quick runoff response to soil surface compaction by line thinning and skid trail installation. Increases of delayed runoff in small catchment may be associated with increase in net precipitation and decrease in evapotranspiration. Our finding showed that changes in internal hydrological flow pathways and associated changes in runoff components due to forest harvesting differ depending on the catchment sizes.

  15. Storm Effects on Net Ecosystem Productivity in Boreal Forests

    NASA Astrophysics Data System (ADS)

    Vestin, Patrik; Grelle, Achim; Lagergren, Fredrik; Hellström, Margareta; Langvall, Ola; Lindroth, Anders

    2010-05-01

    Regional carbon budgets are to some extent determined by disturbance in ecosystems. Disturbance is believed to be partly responsible for the large inter-annual variability of the terrestrial carbon balance. When neglecting anthropogenic disturbance, forest fires have been considered the most important kind of disturbance. However, also insect outbreaks and wind-throw may be major factors in regional carbon budgets. The effects of wind-throw on CO2 fluxes in boreal forests are not well known due to lack of data. Principally, the reduced carbon sequestration capacity, increased substrate availability and severe soil perturbation following wind-throw are expected to result in increased CO2 fluxes from the forest to the atmosphere. In January 2005, the storm Gudrun hit Sweden, which resulted in approx. 66 × 106m3storm-felled stem wood distributed over an area of approx. 272 000 ha. Eddy covariance flux measurements started at storm-felled areas in Asa and Toftaholm in central Sweden during summer 2005. Data from the first months suggests increased CO2 fluxes by a factor of 2.5-10, as compared to normal silviculture (clear-cutting). An important question is how long such enhanced CO2 fluxes persist. The BIOME-BGC model will be calibrated against measured CO2 fluxes from both sites for 2005 through 2009. Modeled data will be used to fill gaps in the data sets and annual carbon balances will be calculated. Data from Asa and Toftaholm will be presented at the conference.

  16. Soil Bacterial Community Structure Responses to Precipitation Reduction and Forest Management in Forest Ecosystems across Germany

    PubMed Central

    Felsmann, Katja; Baudis, Mathias; Gimbel, Katharina; Kayler, Zachary E.; Ellerbrock, Ruth; Bruehlheide, Helge; Bruckhoff, Johannes; Welk, Erik; Puhlmann, Heike; Weiler, Markus; Gessler, Arthur; Ulrich, Andreas

    2015-01-01

    Soil microbial communities play an important role in forest ecosystem functioning, but how climate change will affect the community composition and consequently bacterial functions is poorly understood. We assessed the effects of reduced precipitation with the aim of simulating realistic future drought conditions for one growing season on the bacterial community and its relation to soil properties and forest management. We manipulated precipitation in beech and conifer forest plots managed at different levels of intensity in three different regions across Germany. The precipitation reduction decreased soil water content across the growing season by between 2 to 8% depending on plot and region. T-RFLP analysis and pyrosequencing of the 16S rRNA gene were used to study the total soil bacterial community and its active members after six months of precipitation reduction. The effect of reduced precipitation on the total bacterial community structure was negligible while significant effects could be observed for the active bacteria. However, the effect was secondary to the stronger influence of specific soil characteristics across the three regions and management selection of overstorey tree species and their respective understorey vegetation. The impact of reduced precipitation differed between the studied plots; however, we could not determine the particular parameters being able to modify the response of the active bacterial community among plots. We conclude that the moderate drought induced by the precipitation manipulation treatment started to affect the active but not the total bacterial community, which points to an adequate resistance of the soil microbial system over one growing season. PMID:25875835

  17. Chemical characteristics of two forested Ultisols and two forested Inceptisols relevant to anion production and mobility

    SciTech Connect

    Johnson, D.W.; Cole, D.W.; Horng, F.W.; Van Miegroet, H.; Todd, D.E.

    1981-06-01

    As a prelude to a basic program on soil leaching, some chemical characteristics of two forested Ultisols in eastern Tennessee and two forested Inceptisols in western Washington are discussed in relation to the production and mobility of anions. These soils were chosen in an attempt to provide a range of free iron (Fe) and aluminum (Al) contents (which are hypothesized to be related to anion adsorption) and carbon:nitrogen (C:N) ratios (which are hypothesized to be related to nitrate and bicarbonate production) for field experiments involving C, N, and anion salt additions. The Washington Inceptisols had high free Fe and Al in surface horizons and decreasing free Fe and Al levels with depth, whereas the reverse was true of the Tennessee Ultisols. The Alderwood-red alder and Tarklin (sinkhole) soils had higher N concentrations and lower C:N ratios in their surface horizons than the Alderwood-Douglas-fir and Fullerton soils, respectively, but the reverse was true of subsurface horizons. Patterns of and relationships among the above properties and pH, Bray phosphorus (No. 2); adsorbed and soluble SO/sub 4//sup 2 -/, Cl/sup -/ and NO/sub 3//sup -/; cation exchange capacity; and exchangeable cations are discussed.

  18. Chemical Characteristics of Two Forested Ultisols and Two Forested Inceptisols Relevant to Anion Production and Mobility

    SciTech Connect

    Johnson, D.W.

    2001-01-17

    As a prelude to a basic program on soil leaching, some chemical characteristics of two forested Ultisols in eastern Tennessee and two forested Inceptisols in western Washington are discussed in relation to the production and mobility of anions. These soils were chosen in an attempt to provide a range of free iron (Fe) and aluminum (Al) contents (which are hypothesized to be related to anion adsorption) and carbon:nitrogen (C:N) ratios (which are hypothesized to be related to nitrate and bicarbonate production) for field experiments involving C, N, and anion salt additions. The Washington Inceptisols had high free Fe and Al in surface horizons and decreasing free Fe and Al levels with depth, whereas the reverse was true of the Tennessee Ultisols. The alderwood-red alder and Tarklin (sinkhole) soils had higher N concentrations and lower C:N ratios in their surface horizons than the Alderwood-Douglas-fir and Fullerton soils, respectively, but the reverse was true of subsurface horizons. Patterns of and relationships among the above properties and pH, Bray phosphorus (No. 2); adsorbed and soluble SO{sub 4}{sup 2-}, Cl{sup -}, and NO{sub 3}{sup -}; cation exchange capacity; and exchangeable cations are discussed.

  19. Forest Watch: Using Student Data to Monitor Forest Response to Ground-Level Ozone

    NASA Astrophysics Data System (ADS)

    Spencer, S.; Rock, B. N.

    2006-12-01

    Forest Watch, a k-12 science outreach program begun at the University of New Hampshire (UNH) in 1991, has engaged pre-college students in providing UNH researchers with data on the annual response of white pine (Pinus strobus; a bio-indicator species for ozone exposure) to ground-level ozone across the New England region. Each year, student-collected growth and foliar symptomology data for 5 pine trees adjacent to their schools, along with first-year foliar samples, are submitted to UNH. Key foliar symptoms and student data are compared with summer monthly (JJA) maximum ozone concentrations collected by state and federal ozone monitoring stations across the region. To date, tree health indicators are inversely correlated (r2=0.83;p=0.10) with ozone concentrations: low ozone levels correlate with symptoms of good health (spectral indices diagnostic of high foliar chlorophyll levels and moisture content, normal incremental growth, low number of foliar symptoms), while summers characterized by high ozone concentrations correlate with symptoms of reduced health (low chlorophyll indices and moisture content, reduced incremental growth, increased number of foliar symptoms). In drought years (1999, 2001, 2002, 2003) few foliar symptoms of ozone damage are seen even though ozone levels were high, likely due to drought-induced stomatal closure. Based on student data since 1998, either low ozone summers, or drought summers have resulted in improved health in the sampled trees (n=30). Based on the success of Forest Watch in New England, we are exploring the extension of the program to Colorado as Front Range Forest Watch, operated from Colorado State University (CSU). The primary objective is to develop a student-scientist-local agency project that addresses real ecological issues in northern Colorado, including ozone pollution, and to provide pre-college students and teachers authentic science experiences. CSU runs a GK-12 program with Poudre School District in northern

  20. Belowground responses to elevation in a changing cloud forest.

    PubMed

    Looby, Caitlin I; Maltz, Mia R; Treseder, Kathleen K

    2016-04-01

    Few studies have investigated how soil fungal communities respond to elevation, especially within TMCF (tropical montane cloud forests). We used an elevation gradient in a TMCF in Costa Rica to determine how soil properties, processes, and community composition of fungi change in response to elevation and across seasons. As elevation increased, soil temperature and soil pH decreased, while soil moisture and soil C:N ratios increased with elevation. Responses of these properties varied seasonally. Fungal abundance increased with elevation during wet and dry seasons. Fungal community composition shifted in response to elevation, and to a lesser extent by season. These shifts were accompanied by varying responses of important fungal functional groups during the wet season and the relative abundance of certain fungal phyla. We suggest that elevation and the responses of certain fungal functional groups may be structuring fungal communities along this elevation gradient. TMCF are ecosystems that are rapidly changing due to climate change. Our study suggests that these changes may affect how fungal communities are structured. PMID:27066220

  1. Consequences of increasing bioenergy demand on wood and forests: An application of the Global Forest Products Model

    USGS Publications Warehouse

    Buongiorno, J.; Raunikar, R.; Zhu, S.

    2011-01-01

    The Global Forest Products Model (GFPM) was applied to project the consequences for the global forest sector of doubling the rate of growth of bioenergy demand relative to a base scenario, other drivers being maintained constant. The results showed that this would lead to the convergence of the price of fuelwood and industrial roundwood, raising the price of industrial roundwood by nearly 30% in 2030. The price of sawnwood and panels would be 15% higher. The price of paper would be 3% higher. Concurrently, the demand for all manufactured wood products would be lower in all countries, but the production would rise in countries with competitive advantage. The global value added in wood processing industries would be 1% lower in 2030. The forest stock would be 2% lower for the world and 4% lower for Asia. These effects varied substantially by country. ?? 2011 Department of Forest Economics, SLU Ume??, Sweden.

  2. Climatically induced interannual variability in aboveground production in forest-tundra and northern taiga of central Siberia.

    PubMed

    Knorre, Anastasia A; Kirdyanov, Alexander V; Vaganov, Eugene A

    2006-02-01

    To investigate the variability of primary production of boreal forest ecosystems under the current climatic changes, we compared the dynamics of annual increments and productivity of the main components of plant community (trees, shrubs, mosses) at three sites in the north of Siberia (Russia). Annual radial growth of trees and shrubs was mostly defined by summer temperature regime (positive correlation), but climatic response of woody plants was species specific and depends on local conditions. Dynamics of annual increments of mosses were opposite to tree growth. The difference in climatic response of the different vegetation components of the forest ecosystems indicates that these components seem to be adapted to use climatic conditions during the short and severe northern summer, and decreasing in annual production of one component is usually combined with the increase of other component productivity. Average productivity in the northern forest ecosystems varies from 0.05 to 0.14 t ha(-1) year(-1) for trees, from 0.05 to 0.18 t ha(-1) year(-1) for shrubs and from 0.54 to 0.66 t ha(-1) year(-1) for mosses. Higher values of tree productivity combined with lower annual moss productivity were found in sites in northern taiga in comparison with forest-tundra. Different tendencies in the productivity of the dominant species from each vegetation level (trees, shrubs, mosses) were indicated for the last 10 years studied (1990-1999): while productivity of mosses is increasing, productivity of trees is decreasing, but there is no obvious trend in the productivity of shrubs. Our results show that in the long term, the main contribution to changes in annual biomass productivity in forest-tundra and northern taiga ecosystems under the predicted climatic changes will be determined by living ground cover. PMID:16163553

  3. Intertidal resource use over millennia enhances forest productivity.

    PubMed

    Trant, Andrew J; Nijland, Wiebe; Hoffman, Kira M; Mathews, Darcy L; McLaren, Duncan; Nelson, Trisalyn A; Starzomski, Brian M

    2016-01-01

    Human occupation is usually associated with degraded landscapes but 13,000 years of repeated occupation by British Columbia's coastal First Nations has had the opposite effect, enhancing temperate rainforest productivity. This is particularly the case over the last 6,000 years when intensified intertidal shellfish usage resulted in the accumulation of substantial shell middens. We show that soils at habitation sites are higher in calcium and phosphorous. Both of these are limiting factors in coastal temperate rainforests. Western redcedar (Thuja plicata) trees growing on the middens were found to be taller, have higher wood calcium, greater radial growth and exhibit less top die-back. Coastal British Columbia is the first known example of long-term intertidal resource use enhancing forest productivity and we expect this pattern to occur at archaeological sites along coastlines globally. PMID:27572157

  4. Measuring forest structure along productivity gradients in the Canadian boreal with small-footprint Lidar.

    PubMed

    Bolton, Douglas K; Coops, Nicholas C; Wulder, Michael A

    2013-08-01

    The structure and productivity of boreal forests are key components of the global carbon cycle and impact the resources and habitats available for species. With this research, we characterized the relationship between measurements of forest structure and satellite-derived estimates of gross primary production (GPP) over the Canadian boreal. We acquired stand level indicators of canopy cover, canopy height, and structural complexity from nearly 25,000 km of small-footprint discrete return Light Detection and Ranging (Lidar) data and compared these attributes to GPP estimates derived from the MODerate resolution Imaging Spectroradiometer (MODIS). While limited in our capacity to control for stand age, we removed recently disturbed and managed forests using information on fire history, roads, and anthropogenic change. We found that MODIS GPP was strongly linked to Lidar-derived canopy cover (r = 0.74, p < 0.01), however was only weakly related to Lidar-derived canopy height and structural complexity as these attributes are largely a function of stand age. A relationship was apparent between MODIS GPP and the maximum sampled heights derived from Lidar as growth rates and resource availability likely limit tree height in the prolonged absence of disturbance. The most structurally complex stands, as measured by the coefficient of variation of Lidar return heights, occurred where MODIS GPP was highest as productive boreal stands are expected to contain a wider range of tree heights and transition to uneven-aged structures faster than less productive stands. While MODIS GPP related near-linearly to Lidar-derived canopy cover, the weaker relationships to Lidar-derived canopy height and structural complexity highlight the importance of stand age in determining the structure of boreal forests. We conclude that an improved quantification of how both productivity and disturbance shape stand structure is needed to better understand the current state of boreal forests in

  5. Thermal Plasticity of Photosynthesis: the Role of Acclimation in Forest Responses to a Warming Climate

    SciTech Connect

    Gunderson, Carla A; O'Hara, Keiran H; Campion, Christina M; Walker, Ashley V; Edwards, Nelson T

    2010-01-01

    The increasing air temperatures central to climate change predictions have the potential to alter forest ecosystem function and structure by exceeding temperatures optimal for carbon gain. Such changes are projected to threaten survival of sensitive species, leading to local extinctions, range migrations, and altered forest composition. This study investigated photosynthetic sensitivity to temperature and the potential for acclimation in relation to the climatic provenance of five species of deciduous trees, Liquidambar styraciflua, Quercus rubra, Quercus falcata, Betula alleghaniensis, and Populus grandidentata. Open-top chambers supplied three levels of warming (+0, +2, and +4 C above ambient) over 3 years, tracking natural temperature variability. Optimal temperature for CO2 assimilation was strongly correlated with daytime temperature in all treatments, but assimilation rates at those optima were comparable. Adjustment of thermal optima was confirmed in all species, whether temperatures varied with season or treatment, and regardless of climate in the species' range or provenance of the plant material. Temperature optima from 17 to 34 were observed. Across species, acclimation potentials varied from 0.55 C to 1.07 C per degree change in daytime temperature. Responses to the temperature manipulation were not different from the seasonal acclimation observed in mature indigenous trees, suggesting that photosynthetic responses should not be modeled using static temperature functions, but should incorporate an adjustment to account for acclimation. The high degree of homeostasis observed indicates that direct impacts of climatic warming on forest productivity, species survival, and range limits may be less than predicted by existing models.

  6. Species richness and wood production: a positive association in Mediterranean forests.

    PubMed

    Vilà, Montserrat; Vayreda, Jordi; Comas, Lluís; Ibáñez, Joan Josep; Mata, Teresa; Obón, Berta

    2007-03-01

    A major debate in the study of biodiversity concerns its influence on ecosystem functioning. We compared whether wood production in forests was associated with tree functional group identity (i.e. deciduous, conifer or sclerophylous), tree species richness (1-> or = 5) and tree functional group richness (1-3) by comparing more than 5000 permanent plots distributed across Catalonia (NE Spain). Deciduous forests were more productive than coniferous and sclerophylous forests. Wood production increased with tree species richness. However, functional group richness increased wood production only in sclerophylous forests. When other forest structure, environmental variables and management practices were included in the analysis, tree functional group identity and species richness still remained significant, while functional species richness did not. Our survey indicates that across a regional scale, and across a broad range of environmental conditions, a significant positive association exists between local tree species richness and wood production at least in typical early successional Mediterranean-type forests. PMID:17305807

  7. 76 FR 48120 - Black Hills National Forest, Custer, SD-Mountain Pine Beetle Response Project

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-08

    ... Forest Service Black Hills National Forest, Custer, SD--Mountain Pine Beetle Response Project AGENCY...: This project proposes to treat areas newly infested by mountain pine beetles on approximately 325,000...-rocky-mountain-black-hills@fs.fed.us , with ``MPB Response Project'' in the subject line....

  8. Some aspects of ecophysiological and biogeochemical responses of tropical forests to atmospheric change.

    PubMed

    Chambers, Jeffrey Q; Silver, Whendee L

    2004-03-29

    Atmospheric changes that may affect physiological and biogeochemical processes in old-growth tropical forests include: (i) rising atmospheric CO2 concentration; (ii) an increase in land surface temperature; (iii) changes in precipitation and ecosystem moisture status; and (iv) altered disturbance regimes. Elevated CO2 is likely to directly influence numerous leaf-level physiological processes, but whether these changes are ultimately reflected in altered ecosystem carbon storage is unclear. The net primary productivity (NPP) response of old-growth tropical forests to elevated CO2 is unknown, but unlikely to exceed the maximum experimentally measured 25% increase in NPP with a doubling of atmospheric CO2 from pre-industrial levels. In addition, evolutionary constraints exhibited by tropical plants adapted to low CO2 levels during most of the Late Pleistocene, may result in little response to increased carbon availability. To set a maximum potential response for a Central Amazon forest, using an individual-tree-based carbon cycling model, a modelling experiment was performed constituting a 25% increase in tree growth rate, linked to the known and expected increase in atmospheric CO2. Results demonstrated a maximum carbon sequestration rate of ca. 0.2 Mg C per hectare per year (ha(-1) yr(-1), where 1 ha = 10(4) m2), and a sequestration rate of only 0.05 Mg C ha(-1) yr(-1) for an interval centred on calendar years 1980-2020. This low rate results from slow growing trees and the long residence time of carbon in woody tissues. By contrast, changes in disturbance frequency, precipitation patterns and other environmental factors can cause marked and relatively rapid shifts in ecosystem carbon storage. It is our view that observed changes in tropical forest inventory plots over the past few decades is more probably being driven by changes in disturbance or other environmental factors, than by a response to elevated CO2. Whether these observed changes in tropical forests are

  9. Some aspects of ecophysiological and biogeochemical responses of tropical forests to atmospheric change.

    PubMed Central

    Chambers, Jeffrey Q; Silver, Whendee L

    2004-01-01

    Atmospheric changes that may affect physiological and biogeochemical processes in old-growth tropical forests include: (i) rising atmospheric CO2 concentration; (ii) an increase in land surface temperature; (iii) changes in precipitation and ecosystem moisture status; and (iv) altered disturbance regimes. Elevated CO2 is likely to directly influence numerous leaf-level physiological processes, but whether these changes are ultimately reflected in altered ecosystem carbon storage is unclear. The net primary productivity (NPP) response of old-growth tropical forests to elevated CO2 is unknown, but unlikely to exceed the maximum experimentally measured 25% increase in NPP with a doubling of atmospheric CO2 from pre-industrial levels. In addition, evolutionary constraints exhibited by tropical plants adapted to low CO2 levels during most of the Late Pleistocene, may result in little response to increased carbon availability. To set a maximum potential response for a Central Amazon forest, using an individual-tree-based carbon cycling model, a modelling experiment was performed constituting a 25% increase in tree growth rate, linked to the known and expected increase in atmospheric CO2. Results demonstrated a maximum carbon sequestration rate of ca. 0.2 Mg C per hectare per year (ha(-1) yr(-1), where 1 ha = 10(4) m2), and a sequestration rate of only 0.05 Mg C ha(-1) yr(-1) for an interval centred on calendar years 1980-2020. This low rate results from slow growing trees and the long residence time of carbon in woody tissues. By contrast, changes in disturbance frequency, precipitation patterns and other environmental factors can cause marked and relatively rapid shifts in ecosystem carbon storage. It is our view that observed changes in tropical forest inventory plots over the past few decades is more probably being driven by changes in disturbance or other environmental factors, than by a response to elevated CO2. Whether these observed changes in tropical forests are

  10. CO2 Enhancement of Forest Productivity Constrained by Limited Nitrogen Availability

    SciTech Connect

    Norby, Richard J; Warren, Jeffrey; Iversen, Colleen M; Medlyn, Belinda; McMurtrie, Ross

    2010-01-01

    Stimulation of terrestrial productivity by rising CO2 concentration is projected to reduce the airborne fraction of anthropogenic CO2 emissions; coupled climate-carbon (C) cycle models, including those used in the IPCC Fourth Assessment Report (AR4), are sensitive to this negative feedback on atmospheric CO2 1. The representation of the so-called CO2 fertilization effect in the 11 models used in AR4 and subsequent models2,3 was broadly consistent with experimental evidence from four free-air CO2 enrichment (FACE) experiments, which indicated that net primary productivity (NPP) of forests was increased by 23 2% in response to atmospheric CO2 enrichment to 550 ppm4. Substantial uncertainty remains, however, because of the expectation that feedbacks through the nitrogen (N) cycle will reduce the CO2 stimulation of NPP5,6; these feedbacks were not included in the AR4 models and heretofore have not been confirmed by experiments in forests7. Here, we provide new evidence from a FACE experiment in a deciduous Liquidambar styraciflua (sweetgum) forest stand in Tennessee, USA, that N limitation has significantly reduced the stimulation of NPP by elevated atmospheric CO2 concentration (eCO2). Isotopic evidence and N budget analysis support the premise that N availability in this forest ecosystem has been declining over time, and declining faster in eCO2. Model analyses and evidence from leaf- and stand-level observations provide mechanistic evidence that declining N availability constrained the tree response to eCO2. These results provide a strong rationale and process understanding for incorporating N limitation and N feedback effects in ecosystem and global models used in climate change assessments.

  11. Contrasting Taxonomic and Phylogenetic Diversity Responses to Forest Modifications: Comparisons of Taxa and Successive Plant Life Stages in South African Scarp Forest

    PubMed Central

    Grass, Ingo; Brandl, Roland; Botzat, Alexandra; Neuschulz, Eike Lena; Farwig, Nina

    2015-01-01

    The degradation of natural forests to modified forests threatens subtropical and tropical biodiversity worldwide. Yet, species responses to forest modification vary considerably. Furthermore, effects of forest modification can differ, whether with respect to diversity components (taxonomic or phylogenetic) or to local (α-diversity) and regional (β-diversity) spatial scales. This real-world complexity has so far hampered our understanding of subtropical and tropical biodiversity patterns in human-modified forest landscapes. In a subtropical South African forest landscape, we studied the responses of three successive plant life stages (adult trees, saplings, seedlings) and of birds to five different types of forest modification distinguished by the degree of within-forest disturbance and forest loss. Responses of the two taxa differed markedly. Thus, the taxonomic α-diversity of birds was negatively correlated with the diversity of all plant life stages and, contrary to plant diversity, increased with forest disturbance. Conversely, forest disturbance reduced the phylogenetic α-diversity of all plant life stages but not that of birds. Forest loss neither affected taxonomic nor phylogenetic diversity of any taxon. On the regional scale, taxonomic but not phylogenetic β-diversity of both taxa was well predicted by variation in forest disturbance and forest loss. In contrast to adult trees, the phylogenetic diversity of saplings and seedlings showed signs of contemporary environmental filtering. In conclusion, forest modification in this subtropical landscape strongly shaped both local and regional biodiversity but with contrasting outcomes. Phylogenetic diversity of plants may be more threatened than that of mobile species such as birds. The reduced phylogenetic diversity of saplings and seedlings suggests losses in biodiversity that are not visible in adult trees, potentially indicating time-lags and contemporary shifts in forest regeneration. The different

  12. Litterfall production along successional and altitudinal gradients of subtropical monsoon evergreen broadleaved forests in Guangdong, China

    USGS Publications Warehouse

    Zhou, G.; Guan, L.; Wei, X.; Zhang, Dongxiao; Zhang, Q.; Yan, J.; Wen, D.; Liu, J.; Liu, S.; Huang, Z.; Kong, G.; Mo, J.; Yu, Q.

    2007-01-01

    Evaluation of litterfall production is important for understanding nutrient cycling, forest growth, successional pathways, and interactions with environmental variables in forest ecosystems. Litterfall was intensively studied during the period of 1982-2001 in two subtropical monsoon vegetation gradients in the Dinghushan Biosphere Reserve, Guangdong Province, China. The two gradients include: (1) a successional gradient composed of pine forest (PF), mixed pine and broadleaved forest (MF) and monsoon evergreen broadleaved forest (BF), and (2) an altitudinal gradient composed of Baiyunci ravine rain forest (BRF), Qingyunci ravine rain forest (QRF), BF and mountainous evergreen broadleaved forest (MMF). Mean annual litterfall production was 356, 861 and 849 g m-2 for PF, MF and BF of the successional gradient, and 1016, 1061, 849 and 489 g m-2 for BRF, QRF, BF and MMF of the altitudinal gradient, respectively. As expected, mean annual litterfall of the pioneer forest PF was the lowest, but rapidly increased over the observation period while those in other forests were relatively stable, confirming that forest litterfall production is closely related to successional stages and growth patterns. Leaf proportions of total litterfall in PF, MF, BF, BRF, QRF and MMF were 76.4%, 68.4%, 56.8%, 55.7%, 57.6% and 69.2%, respectively, which were consistent with the results from studies in other evergreen broadleaved forests. Our analysis on litterfall monthly distributions indicated that litterfall production was much higher during the period of April to September compared to other months for all studied forest types. Although there were significant impacts of some climate variables (maximum and effective temperatures) on litterfall production in some of the studied forests, the mechanisms of how climate factors (temperature and rainfall) interactively affect litterfall await further study. ?? 2006 Springer Science+Business Media B.V.

  13. ECOLOGICAL RESPONSE SURFACES FOR NORTH AMERICAN BOREAL TREE SPECIES AND THEIR USE IN FOREST CLASSIFICATION

    EPA Science Inventory

    Empirical ecological response surfaces were derived for eight dominant tree species in the boreal forest region of Canada. tepwise logistic regression was used to model species dominance as a response to five climatic predictor variables. he predictor variables (annual snowfall, ...

  14. Markedly Divergent Tree Assemblage Responses to Tropical Forest Loss and Fragmentation across a Strong Seasonality Gradient

    PubMed Central

    Orihuela, Rodrigo L. L.; Peres, Carlos A.; Mendes, Gabriel; Jarenkow, João A.; Tabarelli, Marcelo

    2015-01-01

    We examine the effects of forest fragmentation on the structure and composition of tree assemblages within three seasonal and aseasonal forest types of southern Brazil, including evergreen, Araucaria, and deciduous forests. We sampled three southernmost Atlantic Forest landscapes, including the largest continuous forest protected areas within each forest type. Tree assemblages in each forest type were sampled within 10 plots of 0.1 ha in both continuous forests and 10 adjacent forest fragments. All trees within each plot were assigned to trait categories describing their regeneration strategy, vertical stratification, seed-dispersal mode, seed size, and wood density. We detected differences among both forest types and landscape contexts in terms of overall tree species richness, and the density and species richness of different functional groups in terms of regeneration strategy, seed dispersal mode and woody density. Overall, evergreen forest fragments exhibited the largest deviations from continuous forest plots in assemblage structure. Evergreen, Araucaria and deciduous forests diverge in the functional composition of tree floras, particularly in relation to regeneration strategy and stress tolerance. By supporting a more diversified light-demanding and stress-tolerant flora with reduced richness and abundance of shade-tolerant, old-growth species, both deciduous and Araucaria forest tree assemblages are more intrinsically resilient to contemporary human-disturbances, including fragmentation-induced edge effects, in terms of species erosion and functional shifts. We suggest that these intrinsic differences in the direction and magnitude of responses to changes in landscape structure between forest types should guide a wide range of conservation strategies in restoring fragmented tropical forest landscapes worldwide. PMID:26309252

  15. Seed germination of montane forest species in response to ash, smoke and heat shock in Mexico

    NASA Astrophysics Data System (ADS)

    Zuloaga-Aguilar, Susana; Briones, Oscar; Orozco-Segovia, Alma

    2011-05-01

    In many fire-prone ecosystems, seed germination is triggered by heat shock, smoke, ash and charred wood. However, few studies concerning the effect of these fire products on the germination of tropical and subtropical species exist. We assessed the effect of fire products and their interactions on seed germination in 12 species that frequently grow in burned areas of pine-oak and mixed forest in a mountainous subtropical area. Each species was exposed to a predetermined treatment of heat shock, which was optimised in accordance with a previous study. For smoke treatments, seeds were immersed in smoke water, whereas for ash treatments, 1.5 g of ash was added to the incubation medium. Germination increased in 92% of the species in response to the products of fire. Both the smoke water and the ash treatments promoted germination in four species that had permeable seed covers and physiological dormancy. Six species with physical dormancy required both heat shock and smoke water or ash to break dormancy. Our results indicate that seed germination response to fire products depends on the species and/or dormancy type. The germination response to the fire products varied between species; therefore, fire products may influence the species composition in post-fire regeneration.

  16. The response of Picea crassifolia forest to climate warming

    NASA Astrophysics Data System (ADS)

    He, Zhibin; Du, Jun; Yang, Junjun; Chen, Longfei; Zhu, Xi

    2014-05-01

    Picea crassifolia forest, an endemic genus mainly distributing in the Qilian Mountain of Northwest China, is very sensitive to climate warming. In the present study, the response of treeline, phenological period, and sap flow of P. crassifolia forest to climate warming were analyzed though a set of observations and experiments. The result showed: (1) During the past 50 years, the temperature had raised at a mean rate of 0.29° C per decade in this region, especially since 1980s (had increased by a total of more than 1.25° C), obviously higher than increment degree IPCC reported. This resulted in the increase of tree recruitment which was significantly positively correlated with the mean growing season temperature and with the mean minimum temperature in June and in winter. Treeline elevation shifted upward by 5.7 to 13.6 m from 1907 to 1957 and by 6.1 to 10.4 m after 1957. (2) By quantifying the canopy phenology events based on satellite-derived datasets (MODIS-NDVI) from 2001 to 2011, and investigating the correlation with climate factors, a conclusion had been drawn which revealed a 3.7 days/decade advance in the length of growing season. Our results suggested that temperature controlled treeline dynamics and phenological period more strongly than precipitation in the Qilian Mountains. (3) In the case of experimental warming (mean daily temperature was increased 0.83° C, mean daily maximum temperature was increased 4.7° C), the trend for the mass growth of P. crassifolia sapling presented a notable increase under conditions of warming, especially for tree height. The data of sap flow showed that warming facilitated the sap flow of sapling in the end of growing season, which indicated the temperature was a major restriction to sap flow rate, especially in the condition of lower temperature.

  17. Plant and soil responses to biosolids application following forest fire.

    PubMed

    Meyer, V F; Redente, E F; Barbarick, K A; Brobst, R B; Paschke, M W; Miller, A L

    2004-01-01

    Soil stability and revegetation is a great concern following forest wildfires. Biosolids application might enhance revegetation efforts and enhance soil stability. In May 1997, we applied Metro Wastewater Reclamation District (Denver, CO, USA) composted biosolids at rates of 0, 5, 10, 20, 40, and 80 Mg ha(-1) to a severely burned, previously forested site near Buffalo Creek, CO to improve soil C and N levels and help establish eight native, seeded grasses. The soils on the site belong to the Sphinx series (sandy-skeletal, mixed, frigid, shallow Typic Ustorthents). Vegetation and soils data were collected for four years following treatment. During the four years following treatment, total plant biomass ranged from approximately 50 to 230 g m(-2) and generally increased with increasing biosolids application. The percentage of bare ground ranged from 4 to 58% and generally decreased with increasing biosolids rate. Higher rates of biosolids application were associated with increased concentrations of N, P, and Zn in tissue of the dominant plant species, streambank wheatgrass [Elymus lanceolatus (Scribn. & J.G. Sm) Gould subsp. lanceolatus], relative to the unamended, unfertilized control. At two months following biosolids application (1997), total soil C and N at soil depths of 0 to 7.5, 7.5 to 15, and 15 to 30 cm showed significant (P < 0.05) linear increases (r2 > 0.88) as biosolids rate increased. The surface soil layer also showed this effect one year after application (1998). For Years 2 through 4 (1999-2001) following treatment, soil C and N levels declined but did not show consistent trends. The increase in productivity and cover resulting from the use of biosolids can aid in the rehabilitation of wildfire sites and reduce soil erosion in ecosystems similar to the Buffalo Creek area. PMID:15224923

  18. Use of Multi-Year MODIS Phenological Data Products to Detect and Monitor Forest Disturbances at Regional and National Scales

    NASA Technical Reports Server (NTRS)

    Spruce, Joseph; Hargrove, William W.; Gasser, Jerry; Smoot, James; Ross, Kenton

    2010-01-01

    This presentation discusses an effort to use select MODIS phenological products for forest disturbance monitoring at the regional and CONUS scales. Forests occur on 1/3 of the U.S. land base and include regionally prevalent forest disturbances that can threaten forest sustainability. Regional and CONUS forest disturbance monitoring is needed for a national forest threat early warning system being developed by the USDA Forest Service with help from NASA, ORNL, and USGS. MODIS NDVI phenology products are being used to develop forest disturbance monitoring capabilities of this EWS.

  19. Spectral response curve models applied to forest cover-type discrimination

    NASA Technical Reports Server (NTRS)

    Hudson, W. D.; Lusch, D. P.

    1984-01-01

    The potential of remote sensing systems to provide a cost-effective inventory tool in the case of forest resources is currently of interest to a variety of natural resources management agencies. A number of studies have been performed regarding the use of Landsat data for mapping forest resources in Michigan. The present paper is concerned with current research, which has been directed toward the development and evaluation of computer-implemented classifications for the identification and characterization of coniferous forest types in Michigan's northern Lower Peninsula. Attention is given to the characteristic response curves from Landsat MSS data, spectral response curve models, and forest cover-type discrimination. It is found that spectral response curve models can be used to evaluate and explain the characteristic spectral responses of coniferous forest types on a snow-covered, winter Landsat scene.

  20. Effects of productivity on biodiversity in forest ecosystems across the United States and China.

    PubMed

    Liang, Jingjing; Watson, James V; Zhou, Mo; Lei, Xiangdong

    2016-04-01

    In the global campaign against biodiversity loss in forest ecosystems, land managers need to know the status of forest biodiversity, but practical guidelines for conserving biodiversity in forest management are lacking. A major obstacle is the incomplete understanding of the relationship between site primary productivity and plant diversity, due to insufficient ecosystem-wide data, especially for taxonomically and structurally diverse forest ecosystems. We investigated the effects of site productivity (the site's inherent capacity to grow timber) on tree species richness across 19 types of forest ecosystems in North America and China through 3 ground-sourced forest inventory data sets (U.S. Forest Inventory and Analysis, Cooperative Alaska Forest Inventory, and Chinese Forest Management Planning Inventory). All forest types conformed to a consistent and highly significant (P < 0.001) hump-shaped unimodal relationship, of which the generalized coefficients of determination averaged 20.5% over all the forest types. That is, tree species richness first increased as productivity increased at a progressively slower rate, and, after reaching a maximum, richness started to decline. Our consistent findings suggest that forests of high productivity would sustain few species because they consist mostly of flat homogeneous areas lacking an environmental gradient along which a diversity of species with different habitats can coexist. The consistency of the productivity-biodiversity relationship among the 3 data sets we examined makes it possible to quantify the expected tree species richness that a forest stand is capable of sustaining, and a comparison between the actual species richness and the sustainable values can be useful in prioritizing conservation efforts. PMID:26954431

  1. Database Overlap vs. Complementary Coverage in Forestry and Forest Products: Factors in Database Acquisition.

    ERIC Educational Resources Information Center

    Hoover, Ryan E.

    This study examines (1) subject content, (2) file size, (3) types of documents indexed, (4) range of years spanned, and (5) level of indexing and abstracting in five databases which collectively provide extensive coverage of the forestry and forest products industries: AGRICOLA, CAB ABSTRACTS, FOREST PRODUCTS (AIDS), PAPERCHEM, and PIRA. The…

  2. 76 FR 19474 - Columbia Forest Products, Inc., Presque Isle Division; Presque Isle, Maine; Notice of Revised...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-07

    ... Department's Notice of determination was published in the Federal Register on October 25, 2010 (75 FR 65514... Act, 19 U.S.C. 2273, I make the following certification: All workers of Columbia Forest Products, Inc... Employment and Training Administration Columbia Forest Products, Inc., Presque Isle Division; Presque...

  3. 77 FR 35061 - Roseburg Forest Products Composite Panels Division Missoula, Montana; Notice of Negative...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-12

    ... former workers of Roseburg Forest Products, Composite Panels Division, Missoula, Montana (subject firm). The Department's Notice was published in the Federal Register on March 26, 2012 (77 FR 17524). The... Employment and Training Administration Roseburg Forest Products Composite Panels Division Missoula,...

  4. 3 CFR 8587 - Proclamation 8587 of October 15, 2010. National Forest Products Week, 2010

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 3 The President 1 2011-01-01 2011-01-01 false Proclamation 8587 of October 15, 2010. National Forest Products Week, 2010 8587 Proclamation 8587 Presidential Documents Proclamations Proclamation 8587 of October 15, 2010 Proc. 8587 National Forest Products Week, 2010By the President of the United States of America A Proclamation Since the...

  5. 3 CFR 9044 - Proclamation 9044 of October 18, 2013. National Forest Products Week, 2013

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 3 The President 1 2014-01-01 2014-01-01 false Proclamation 9044 of October 18, 2013. National Forest Products Week, 2013 9044 Proclamation 9044 Presidential Documents Proclamations Proclamation 9044 of October 18, 2013 Proc. 9044 National Forest Products Week, 2013By the President of the United States of America A Proclamation Our...

  6. 77 FR 27085 - TMI Forest Products, Inc., Crane Creek Division, Morton, WA; Notice of Negative Determination...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-08

    ... Determination was published in the Federal Register on March 6, 2012 (77 FR 13355). Pursuant to 29 CFR 90.18(c... Employment and Training Administration TMI Forest Products, Inc., Crane Creek Division, Morton, WA; Notice of... (TAA), applicable to workers and former workers of TMI Forest Products, Inc., Crane Creek...

  7. Drought Stress Response of Dry Forest Trees of the Brazilian Caatinga

    NASA Astrophysics Data System (ADS)

    Menezes, R.; Worbes, M.

    2015-12-01

    Martin Worbes and Romulo Menezes In the frame of the "Tropi-Dry" network we studied drought response strategies of six tree species in a Caatinga forest at the Fazenda Tamandua near Patos in Paraiba, NE Brazil. We selected the tree species as representatives of the different phenological ecotypes: evergreen, deciduous and stem succulent. The deciduous group comprised N-fixing as well as non N-fixing Leguminosae. Over an entire vegetation period (dry and wet-season) we monitored their phenological behaviour, photosynthesis rates, stomata conductance and water potential, measured if leaves were present and we estimated seasonal variations in stable carbon and N15 content of the leaves. The major results are: Evergreen species (e.g. Capparis) may compensate low carbon-fixing rates in the wet season with a much longer vegetation period as the deciduous species. Stem succulents (Jatropha) do not fulfill the expectations of being high productive species under drought stress conditions, while the N-fixing Mimosa performed in particular at the end and the beginning of the dry period better than the rest of the investigated species. In general the results may help to understand different strategies of tree species in respect to extended dry periods of at least six months as in our study area and their role in carbon sequestration of tropical dry forests. The variety of observed strategies may contribute to the resilience of the ecosystem tropical dry forests.

  8. Climate seasonality limits leaf carbon assimilation and wood productivity in tropical forests

    NASA Astrophysics Data System (ADS)

    Wagner, Fabien H.; Hérault, Bruno; Bonal, Damien; Stahl, Clément; Anderson, Liana O.; Baker, Timothy R.; Becker, Gabriel Sebastian; Beeckman, Hans; Boanerges Souza, Danilo; Botosso, Paulo Cesar; Bowman, David M. J. S.; Bräuning, Achim; Brede, Benjamin; Irving Brown, Foster; Julio Camarero, Jesus; Barbosa Camargo, Plínio; Cardoso, Fernanda C. G.; Alvim Carvalho, Fabrício; Castro, Wendeson; Koloski Chagas, Rubens; Chave, Jérome; Chidumayo, Emmanuel N.; Clark, Deborah A.; Capellotto Costa, Flavia Regina; Couralet, Camille; Henrique da Silva Mauricio, Paulo; Dalitz, Helmut; Resende de Castro, Vinicius; Eloisa de Freitas Milani, Jaçanan; Consuelo de Oliveira, Edilson; de Souza Arruda, Luciano; Devineau, Jean-Louis; Drew, David M.; Dünisch, Oliver; Durigan, Giselda; Elifuraha, Elisha; Fedele, Marcio; Ferreira Fedele, Ligia; Figueiredo Filho, Afonso; Guimarães Finger, César Augusto; César Franco, Augusto; Lima Freitas Júnior, João; Galvão, Franklin; Gebrekirstos, Aster; Gliniars, Robert; Maurício Lima de Alencastro Graça, Paulo; Griffiths, Anthony D.; Grogan, James; Guan, Kaiyu; Homeier, Jürgen; Raquel Kanieski, Maria; Khoon Kho, Lip; Koenig, Jennifer; Valerio Kohler, Sintia; Krepkowski, Julia; Pires Lemos-Filho, José; Lieberman, Diana; Lieberman, Milton Eugene; Lisi, Claudio Sergio; Longhi Santos, Tomaz; López Ayala, José Luis; Eijji Maeda, Eduardo; Malhi, Yadvinder; Maria, Vivian R. B.; Marques, Marcia C. M.; Marques, Renato; Maza Chamba, Hector; Mbwambo, Lawrence; Liana Lisboa Melgaço, Karina; Mendivelso, Hooz Angela; Murphy, Brett P.; O'Brien, Joseph J.; Oberbauer, Steven F.; Okada, Naoki; Pélissier, Raphaël; Prior, Lynda D.; Alejandro Roig, Fidel; Ross, Michael; Rodrigo Rossatto, Davi; Rossi, Vivien; Rowland, Lucy; Rutishauser, Ervan; Santana, Hellen; Schulze, Mark; Selhorst, Diogo; Rodrigues Silva, Williamar; Silveira, Marcos; Spannl, Susanne; Swaine, Michael D.; Julio Toledo, José; Toledo, Marcos Miranda; Toledo, Marisol; Toma, Takeshi; Tomazello Filho, Mario; Valdez Hernández, Juan Ignacio; Verbesselt, Jan; Aparecida Vieira, Simone; Vincent, Grégoire; Volkmer de Castilho, Carolina; Volland, Franziska; Worbes, Martin; Bolzan Zanon, Magda Lea; Aragão, Luiz E. O. C.

    2016-04-01

    The seasonal climate drivers of the carbon cycle in tropical forests remain poorly known, although these forests account for more carbon assimilation and storage than any other terrestrial ecosystem. Based on a unique combination of seasonal pan-tropical data sets from 89 experimental sites (68 include aboveground wood productivity measurements and 35 litter productivity measurements), their associated canopy photosynthetic capacity (enhanced vegetation index, EVI) and climate, we ask how carbon assimilation and aboveground allocation are related to climate seasonality in tropical forests and how they interact in the seasonal carbon cycle. We found that canopy photosynthetic capacity seasonality responds positively to precipitation when rainfall is < 2000 mm yr-1 (water-limited forests) and to radiation otherwise (light-limited forests). On the other hand, independent of climate limitations, wood productivity and litterfall are driven by seasonal variation in precipitation and evapotranspiration, respectively. Consequently, light-limited forests present an asynchronism between canopy photosynthetic capacity and wood productivity. First-order control by precipitation likely indicates a decrease in tropical forest productivity in a drier climate in water-limited forest, and in current light-limited forest with future rainfall < 2000 mm yr-1.

  9. Tree Size Inequality Reduces Forest Productivity: An Analysis Combining Inventory Data for Ten European Species and a Light Competition Model.

    PubMed

    Bourdier, Thomas; Cordonnier, Thomas; Kunstler, Georges; Piedallu, Christian; Lagarrigues, Guillaume; Courbaud, Benoit

    2016-01-01

    Plant structural diversity is usually considered as beneficial for ecosystem functioning. For instance, numerous studies have reported positive species diversity-productivity relationships in plant communities. However, other aspects of structural diversity such as individual size inequality have been far less investigated. In forests, tree size inequality impacts directly tree growth and asymmetric competition, but consequences on forest productivity are still indeterminate. In addition, the effect of tree size inequality on productivity is likely to vary with species shade-tolerance, a key ecological characteristic controlling asymmetric competition and light resource acquisition. Using plot data from the French National Geographic Agency, we studied the response of stand productivity to size inequality for ten forest species differing in shade tolerance. We fitted a basal area stand production model that included abiotic factors, stand density, stand development stage and a tree size inequality index. Then, using a forest dynamics model we explored whether mechanisms of light interception and light use efficiency could explain the tree size inequality effect observed for three of the ten species studied. Size inequality negatively affected basal area increment for seven out of the ten species investigated. However, this effect was not related to the shade tolerance of these species. According to the model simulations, the negative tree size inequality effect could result both from reduced total stand light interception and reduced light use efficiency. Our results demonstrate that negative relationships between size inequality and productivity may be the rule in tree populations. The lack of effect of shade tolerance indicates compensatory mechanisms between effect on light availability and response to light availability. Such a pattern deserves further investigations for mixed forests where complementarity effects between species are involved. When studying the

  10. Tree Size Inequality Reduces Forest Productivity: An Analysis Combining Inventory Data for Ten European Species and a Light Competition Model

    PubMed Central

    Bourdier, Thomas; Cordonnier, Thomas; Kunstler, Georges; Piedallu, Christian; Lagarrigues, Guillaume; Courbaud, Benoit

    2016-01-01

    Plant structural diversity is usually considered as beneficial for ecosystem functioning. For instance, numerous studies have reported positive species diversity-productivity relationships in plant communities. However, other aspects of structural diversity such as individual size inequality have been far less investigated. In forests, tree size inequality impacts directly tree growth and asymmetric competition, but consequences on forest productivity are still indeterminate. In addition, the effect of tree size inequality on productivity is likely to vary with species shade-tolerance, a key ecological characteristic controlling asymmetric competition and light resource acquisition. Using plot data from the French National Geographic Agency, we studied the response of stand productivity to size inequality for ten forest species differing in shade tolerance. We fitted a basal area stand production model that included abiotic factors, stand density, stand development stage and a tree size inequality index. Then, using a forest dynamics model we explored whether mechanisms of light interception and light use efficiency could explain the tree size inequality effect observed for three of the ten species studied. Size inequality negatively affected basal area increment for seven out of the ten species investigated. However, this effect was not related to the shade tolerance of these species. According to the model simulations, the negative tree size inequality effect could result both from reduced total stand light interception and reduced light use efficiency. Our results demonstrate that negative relationships between size inequality and productivity may be the rule in tree populations. The lack of effect of shade tolerance indicates compensatory mechanisms between effect on light availability and response to light availability. Such a pattern deserves further investigations for mixed forests where complementarity effects between species are involved. When studying the

  11. Threshold Responses of Forest Birds to Landscape Changes around Exurban Development

    PubMed Central

    Suarez-Rubio, Marcela; Wilson, Scott; Leimgruber, Peter; Lookingbill, Todd

    2013-01-01

    Low-density residential development (i.e., exurban development) is often embedded within a matrix of protected areas and natural amenities, raising concern about its ecological consequences. Forest-dependent species are particularly susceptible to human settlement even at low housing densities typical of exurban areas. However, few studies have examined the response of forest birds to this increasingly common form of land conversion. The aim of this study was to assess whether, how, and at what scale forest birds respond to changes in habitat due to exurban growth. We evaluated changes in habitat composition (amount) and configuration (arrangement) for forest and forest-edge species around North America Breeding Bird Survey (BBS) stops between 1986 and 2009. We used Threshold Indicator Taxa Analysis to detect change points in species occurrence at two spatial extents (400-m and 1-km radius buffer). Our results show that exurban development reduced forest cover and increased habitat fragmentation around BBS stops. Forest birds responded nonlinearly to most measures of habitat loss and fragmentation at both the local and landscape extents. However, the strength and even direction of the response changed with the extent for several of the metrics. The majority of forest birds’ responses could be predicted by their habitat preferences indicating that management practices in exurban areas might target the maintenance of forested habitats, for example through easements or more focused management for birds within existing or new protected areas. PMID:23826325

  12. New estimates of temperature response of leaf photosynthesis in Amazon forest trees, its acclimation to mean temperature change and consequences for modelling climate response to rain forests.

    NASA Astrophysics Data System (ADS)

    Kruijt, B.; Jans, W.; Vasconcelos, S.; Tribuzy, E. S.; Felsemburgh, C.; Eliane, M.; Rowland, L.; da Costa, A. C. L.; Meir, P.

    2014-12-01

    In many dynamic vegetation models, degradation of the tropical forests is induced because they assume that productivity falls rapidly when temperatures rise in the region of 30-40°C. Apart plant respiration, this is due to the assumptions on the temperature optima of photosynthetic capacity, which are low and can differ widely between models, where in fact hardly any empirical information is available for tropical forests. Even less is known about the possibility that photosynthesis will acclimate to changing temperatures. The objective of this study to is to provide better estimates for optima, as well as to determine whether any acclimation to temperature change is to be expected. We present both new and hitherto unpublished data on the temperature response of photosynthesis of Amazon rainforest trees, encompassing three sites, several species and five field campaigns. Leaf photosynthesis and its parameters were determined at a range of temperatures. To study the long-term (seasonal) acclimation of this response, this was combined with an artificial, in situ, multi-season leaf heating experiment. The data show that, on average for all non-heated cases, the photosynthetic parameter Vcmax weakly peaks between 35 and 40 ˚C, while heating does not have a clearly significant effect. Results for Jmax are slightly different, with sharper peaks. Scatter was relatively high, which could indicate weak overall temperature dependence. The combined results were used to fit new parameters to the various temperature response curve functions in a range of DGVMs. The figure shows a typical example: while the default Jules model assumes a temperature optimum for Vcmax at around 33 ˚C, the data suggest that Vcmax keeps rising up to at least 40 ˚C. Of course, calculated photosynthesis, obtained by applying this Vcmax in the Farquhar model, peaks at lower temperature. Finally, the implication of these new model parameters for modelled climate change impact on modelled Amazon

  13. Climate response to Amazon forest replacement by heterogeneous crop cover

    NASA Astrophysics Data System (ADS)

    Badger, A. M.; Dirmeyer, P. A.

    2015-11-01

    Previous modeling studies with atmospheric general circulation models and basic land surface schemes to balance energy and water budgets have shown that by removing the natural vegetation over the Amazon, the region's climate becomes warmer and drier. In this study we use a fully coupled Earth system model and replace tropical forests by a distribution of six common tropical crops with variable planting dates, physiological parameters and irrigation. There is still general agreement with previous studies as areal averages show a warmer (+1.4 K) and drier (-0.35 mm day-1) climate. Using an interactive crop model with a realistic crop distribution shows that regions of vegetation change experience different responses dependent upon the initial tree coverage and whether the replacement vegetation is irrigated, with seasonal changes synchronized to the cropping season. Areas with initial tree coverage greater than 80 % show an increase in coupling with the atmosphere after deforestation, suggesting land use change could heighten sensitivity to climate anomalies, while irrigation acts to dampen coupling with the atmosphere.

  14. Climate response to Amazon forest replacement by heterogeneous crop cover

    NASA Astrophysics Data System (ADS)

    Badger, A. M.; Dirmeyer, P. A.

    2015-01-01

    Previous modeling studies with atmospheric general circulation models and basic land surface schemes to balance energy and water budgets have shown that by removing the natural vegetation over the Amazon, the region's climate becomes warmer and drier. In this study we use a fully coupled Earth System Model and replace tropical forests by a distribution of six common tropical crops with variable planting dates, physiological parameters and irrigation. There is still general agreement with previous studies as areal averages show a warmer (+1.4 K) and drier (-0.35 mm day-1) climate. Using an interactive crop model with a realistic crop distribution shows that regions of vegetation change experience different responses dependent upon the initial tree coverage and whether the replacement vegetation is irrigated, with seasonal changes synchronized to the cropping season. Areas with initial tree coverage greater than 80% show an increase in coupling with atmosphere after deforestation, suggesting land use change could heighten sensitivity to climate anomalies, while irrigation acts to dampen coupling with atmosphere.

  15. Short and long-term carbon balance of bioenergy electricity production fueled by forest treatments

    PubMed Central

    2014-01-01

    Background Forests store large amounts of carbon in forest biomass, and this carbon can be released to the atmosphere following forest disturbance or management. In the western US, forest fuel reduction treatments designed to reduce the risk of high severity wildfire can change forest carbon balance by removing carbon in the form of biomass, and by altering future potential wildfire behavior in the treated stand. Forest treatment carbon balance is further affected by the fate of this biomass removed from the forest, and the occurrence and intensity of a future wildfire in this stand. In this study we investigate the carbon balance of a forest treatment with varying fates of harvested biomass, including use for bioenergy electricity production, and under varying scenarios of future disturbance and regeneration. Results Bioenergy is a carbon intensive energy source; in our study we find that carbon emissions from bioenergy electricity production are nearly twice that of coal for the same amount of electricity. However, some emissions from bioenergy electricity production are offset by avoided fossil fuel electricity emissions. The carbon benefit achieved by using harvested biomass for bioenergy electricity production may be increased through avoided pyrogenic emissions if the forest treatment can effectively reduce severity. Conclusion Forest treatments with the use of harvested biomass for electricity generation can reduce carbon emissions to the atmosphere by offsetting fossil fuel electricity generation emissions, and potentially by avoided pyrogenic emissions due to reduced intensity and severity of a future wildfire in the treated stand. However, changes in future wildfire and regeneration regimes may affect forest carbon balance and these climate-induced changes may influence forest carbon balance as much, or more, than bioenergy production. PMID:25187788

  16. Response of soil respiration to acid rain in forests of different maturity in southern China.

    PubMed

    Liang, Guohua; Liu, Xingzhao; Chen, Xiaomei; Qiu, Qingyan; Zhang, Deqiang; Chu, Guowei; Liu, Juxiu; Liu, Shizhong; Zhou, Guoyi

    2013-01-01

    The response of soil respiration to acid rain in forests, especially in forests of different maturity, is poorly understood in southern China despite the fact that acid rain has become a serious environmental threat in this region in recent years. Here, we investigated this issue in three subtropical forests of different maturity [i.e. a young pine forest (PF), a transitional mixed conifer and broadleaf forest (MF) and an old-growth broadleaved forest (BF)] in southern China. Soil respiration was measured over two years under four simulated acid rain (SAR) treatments (CK, the local lake water, pH 4.5; T1, water pH 4.0; T2, water pH 3.5; and T3, water pH 3.0). Results indicated that SAR did not significantly affect soil respiration in the PF, whereas it significantly reduced soil respiration in the MF and the BF. The depressed effects on both forests occurred mostly in the warm-wet seasons and were correlated with a decrease in soil microbial activity and in fine root biomass caused by soil acidification under SAR. The sensitivity of the response of soil respiration to SAR showed an increasing trend with the progressive maturity of the three forests, which may result from their differences in acid buffering ability in soil and in litter layer. These results indicated that the depressed effect of acid rain on soil respiration in southern China may be more pronounced in the future in light of the projected change in forest maturity. However, due to the nature of this field study with chronosequence design and the related pseudoreplication for forest types, this inference should be read with caution. Further studies are needed to draw rigorous conclusions regarding the response differences among forests of different maturity using replicated forest types. PMID:23626790

  17. Response of Soil Respiration to Acid Rain in Forests of Different Maturity in Southern China

    PubMed Central

    Chen, Xiaomei; Qiu, Qingyan; Zhang, Deqiang; Chu, Guowei; Liu, Juxiu; Liu, Shizhong; Zhou, Guoyi

    2013-01-01

    The response of soil respiration to acid rain in forests, especially in forests of different maturity, is poorly understood in southern China despite the fact that acid rain has become a serious environmental threat in this region in recent years. Here, we investigated this issue in three subtropical forests of different maturity [i.e. a young pine forest (PF), a transitional mixed conifer and broadleaf forest (MF) and an old-growth broadleaved forest (BF)] in southern China. Soil respiration was measured over two years under four simulated acid rain (SAR) treatments (CK, the local lake water, pH 4.5; T1, water pH 4.0; T2, water pH 3.5; and T3, water pH 3.0). Results indicated that SAR did not significantly affect soil respiration in the PF, whereas it significantly reduced soil respiration in the MF and the BF. The depressed effects on both forests occurred mostly in the warm-wet seasons and were correlated with a decrease in soil microbial activity and in fine root biomass caused by soil acidification under SAR. The sensitivity of the response of soil respiration to SAR showed an increasing trend with the progressive maturity of the three forests, which may result from their differences in acid buffering ability in soil and in litter layer. These results indicated that the depressed effect of acid rain on soil respiration in southern China may be more pronounced in the future in light of the projected change in forest maturity. However, due to the nature of this field study with chronosequence design and the related pseudoreplication for forest types, this inference should be read with caution. Further studies are needed to draw rigorous conclusions regarding the response differences among forests of different maturity using replicated forest types. PMID:23626790

  18. Response of a forest ecotone to ionizing radiation. Final report

    SciTech Connect

    Murphy, P.G.; Sharitz, R.R.

    1986-05-01

    Compositional and structural characteristics of three forest types, including aspen dominated, maple-birch dominated, and an intervening ecotone (midecotone), were studied before and after irradiation in northern Wisconsin. The cumulative exposure resulting from 3300 hours of point-source gamma irradiation was estimated to be 55 kR at 10 m. In all three areas, the density of seedlings at 10 m was greatly reduced within a year following the 1972 radiation event. In the maple-birch area, seedlings were virtually absent at 10 m until 1982 and 1983 when their numbers were comparable to preirradiation levels, and 1984 when they were more than twice as abundant. In the aspen and midecotone areas, 1984 seedling densities at 10 m were only 42 and 17%, respectively, of the preirradiation levels. Similar but less pronounced seedling trends were observed at 20 m but not beyond that distance. Woody plants of tree stature were eliminated at 10 m in all three areas within two years of irradiation but by 1979 (maple-birch area) and 1982 (midecotone area) this size class was once again represented. By 1984 only the aspen area lacked plants at least 2.5 cm in dbh. In 1984, 12 years subsequent to irradiation, total leaf litter production was 109 and 97% of 1971 preirradiation levels at 10 m in aspen and midecotone areas, respectively. But at 10 m in the maple-birch area, it was only 58% of the preirradiation level.

  19. Recycling research progress at the forest products laboratory. Forest Service general technical report

    SciTech Connect

    1995-09-01

    This document summarizes accomplishments of USDA Forest Service researchers in the area of recycling. Specifically, it describes work in economic assessment paper recycling, recycled housing and industrial applications of recycle materials, other recycled applications, and technology transfer. The literature list includes the references cited in the text and additional publications regarding Forest Service recycling research.

  20. Fires increase Amazon forest productivity through increases in diffuse radiation

    NASA Astrophysics Data System (ADS)

    Rap, A.; Spracklen, D. V.; Mercado, L.; Reddington, C. L.; Haywood, J. M.; Ellis, R. J.; Phillips, O. L.; Artaxo, P.; Bonal, D.; Restrepo Coupe, N.; Butt, N.

    2015-06-01

    Atmospheric aerosol scatters solar radiation increasing the fraction of diffuse radiation and the efficiency of photosynthesis. We quantify the impacts of biomass burning aerosol (BBA) on diffuse radiation and plant photosynthesis across Amazonia during 1998-2007. Evaluation against observed aerosol optical depth allows us to provide lower and upper BBA emissions estimates. BBA increases Amazon basin annual mean diffuse radiation by 3.4-6.8% and net primary production (NPP) by 1.4-2.8%, with quoted ranges driven by uncertainty in BBA emissions. The enhancement of Amazon basin NPP by 78-156 Tg C a-1 is equivalent to 33-65% of the annual regional carbon emissions from biomass burning. This NPP increase occurs during the dry season and acts to counteract some of the observed effect of drought on tropical production. We estimate that 30-60 Tg C a-1 of this NPP enhancement is within woody tissue, accounting for 8-16% of the observed carbon sink across mature Amazonian forests.

  1. Production and retention of methylmercury in inundated boreal forest soils.

    PubMed

    Rolfhus, Kristofer R; Hurley, James P; Bodaly, Richard A Drew; Perrine, Gregory

    2015-03-17

    The Flooded Uplands Dynamics Experiment (FLUDEX) was an ecosystem-scale study examining the production of methylmercury (MeHg) and greenhouse gases from reservoirs constructed on an upland boreal forest landscape in order to quantify their dependence upon carbon stores. We detail the within-reservoir production and storage of MeHg before, during, and nine years after the experiment. The reservoirs were net MeHg producers during the first two years of flooding, and net demethylating systems afterward. During years 1-3, a rapid pulse of MeHg and total Hg was observed in floodwater, followed by substantial increases in MeHg in seston and sediment. Resampling of the dry reservoirs nine years after the experiment ended indicated that organic soil MeHg was still 8 to 52-fold higher than preflood conditions, and averaged 86% of the levels recorded at the end of the third flooding year. Both total Hg and MeHg retention in soil were a strong function of organic carbon content. The time scale of soil MeHg retention may help explain the decadal time lag frequently observed for the decrease of piscivorous fish Hg concentrations in new reservoirs. Predicted extreme precipitation events associated with climate change may serve to make landscapes more susceptible to this process. PMID:25668143

  2. PROJECTION OF RESPONSE OF TREES AND FORESTS TO ACIDIC DEPOSITION AND ASSOCIATED POLLUTANTS

    EPA Science Inventory

    In 1986 the National, Acid Precipitation Assessment Program (NAPAP) established the Forest Response Program (FRP) to assess the effects of acidic deposition and associated pollutants on forests. Modeling studies were developed in parallel with both field studies on the pattern an...

  3. Physiology-phenology interactions in a productive semi-arid pine forest.

    PubMed

    Maseyk, Kadmiel S; Lin, Tongbao; Rotenberg, Eyal; Grünzweig, José M; Schwartz, Amnon; Yakir, Dan

    2008-01-01

    This study explored possible advantages conferred by the phase shift between leaf phenology and photosynthesis seasonality in a semi-arid Pinus halepensis forest system, not seen in temperate sites. Leaf-scale measurements of gas exchange, nitrogen and phenology were used on daily, seasonal and annual time-scales. Peak photosynthesis was in late winter, when high soil moisture, mild temperatures and low leaf vapour pressure deficit (D(L)) allowed high rates associated with high water- and nitrogen-use efficiencies. Self-sustained new needle growth through the dry and hot summer maximized photosynthesis in the following wet season, without straining carbon storage. Low rates of water loss were associated with increasing sensitivity of stomatal conductance (g(s)) to soil moisture below a relative extractable water (REW) of 0.4, and decreased g(s )sensitivity to D(L) below REW of approx. 0.2. This response was captured by the modified Ball-Berry (Leuning) model. While most physiological parameters and responses measured were typical of temperate pines, the photosynthesis-phenological phasing contributed to high productivity under warm-dry conditions. This contrasts with reported effects of short-term periodical droughts and could lead to different predictions of the effect of warming and drying climate on pine forest productivity. PMID:18331428

  4. Gaseous mercury fluxes from forest soils in response to forest harvesting intensity: a field manipulation experiment.

    PubMed

    Mazur, M; Mitchell, C P J; Eckley, C S; Eggert, S L; Kolka, R K; Sebestyen, S D; Swain, E B

    2014-10-15

    Forest harvesting leads to changes in soil moisture, temperature and incident solar radiation, all strong environmental drivers of soil-air mercury (Hg) fluxes. Whether different forest harvesting practices significantly alter Hg fluxes from forest soils is unknown. We conducted a field-scale experiment in a northern Minnesota deciduous forest wherein gaseous Hg emissions from the forest floor were monitored after two forest harvesting prescriptions, a traditional clear-cut and a clearcut followed by biomass harvest, and compared to an un-harvested reference plot. Gaseous Hg emissions were measured in quadruplicate at four different times between March and November 2012 using Teflon dynamic flux chambers. We also applied enriched Hg isotope tracers and separately monitored their emission in triplicate at the same times as ambient measurements. Clearcut followed by biomass harvesting increased ambient Hg emissions the most. While significant intra-site spatial variability was observed, Hg emissions from the biomass harvested plot (180 ± 170 ng m(-2)d(-1)) were significantly greater than both the traditional clearcut plot (-40 ± 60 ng m(-2)d(-1)) and the un-harvested reference plot (-180 ± 115 ng m(-2)d(-1)) during July. This difference was likely a result of enhanced Hg(2+) photoreduction due to canopy removal and less shading from downed woody debris in the biomass harvested plot. Gaseous Hg emissions from more recently deposited Hg, as presumably representative of isotope tracer measurements, were not significantly influenced by harvesting. Most of the Hg tracer applied to the forest floor became sequestered within the ground vegetation and debris, leaf litter, and soil. We observed a dramatic lessening of tracer Hg emissions to near detection levels within 6 months. As post-clearcutting residues are increasingly used as a fuel or fiber resource, our observations suggest that gaseous Hg emissions from forest soils will increase, although it is not yet clear for

  5. Relationships between net primary productivity and forest stand age derived from Forest Inventory and Analysis data and remote sensing imagery

    NASA Astrophysics Data System (ADS)

    He, L.; Chen, J. M.; Pan, Y.; Birdsey, R.

    2010-12-01

    Forest net primary productivity (NPP) varies greatly with stand age, and quantitative information on NPP-age relationship is therefore fundamentally important for forest carbon cycle modeling. We may use four terms to calculate NPP: annual accumulation of live biomass, annual mortality of aboveground and belowground biomass, foliage turnover to soil, and fine root turnover in soil. To derive NPP-age relationships for US forests, the Forest Inventory and Analysis (FIA) data are used to estimate the first two terms. The last two terms make up more than 50% of total NPP, but their estimates are highly uncertain based on limited available empirical relationships between aboveground biomass and foliage or fine root biomass. These estimates are mostly confounded by unknown variations of the turnover rates (TR) related to stand age because such field information is rare. To resolve this problem, we developed a new approach by using a leaf area index (LAI) map and a forest age map at 1 km resolution to derive LAI-age relationships for 18 major forest species groups in the USA. These relationships are then used to derive foliage TR using species-specific leaf longevity values. These relationships are also used for estimating the fine root TR based on reliable relationships between fine root and foliage TR. This combination of FIA and remote sensing data allows us for the first time to derive reliable NPP-age relationships for different forest types in USA (Figure 1). The derived relationships show a general temporal pattern of rapid increase in NPP in early ages, peak growth in mid-ages, and slow decline in old ages. The patterns are subjected to climate conditions, and can also be influenced by forest management. These relationships are further generalized for three major forest biomes for continental-scale carbon cycle modeling in conjunction with remotely sensed land cover types. The NPP relationships derived here may have many uses for analysis of management and climate

  6. Evaluating Spatial-Temporal Dynamics of Net Primary Productivity of Different Forest Types in Northeastern China Based on Improved FORCCHN

    PubMed Central

    Zhao, Junfang; Yan, Xiaodong; Guo, Jianping; Jia, Gensuo

    2012-01-01

    An improved individual-based forest ecosystem carbon budget model for China (FORCCHN) was applied to investigate the spatial-temporal dynamics of net primary productivity of different forest types in northeastern China. In this study, the forests of northeastern China were categorized into four ecological types according to their habitats and generic characteristics (evergreen broadleaf forest, deciduous broadleaf forest, evergreen needleleaf forest and deciduous needleleaf forest). The results showed that distribution and change of forest NPP in northeastern China were related to the different forest types. From 1981 to 2002, among the forest types in northeastern China, per unit area NPP and total NPP of deciduous broadleaf forest were the highest, with the values of 729.4 gC/(m2•yr) and 106.0 TgC/yr, respectively, followed by mixed broadleaf- needleleaf forest, deciduous needleleaf forest and evergreen needleleaf forest. From 1981 to 2002, per unit area NPP and total NPP of different forest types in northeastern China exhibited significant trends of interannual increase, and rapid increase was found between the 1980s and 1990s. The contribution of the different forest type’s NPP to total NPP in northeastern China was clearly different. The greatest was deciduous broadleaf forest, followed by mixed broadleaf- needleleaf forest and deciduous needleleaf forest. The smallest was evergreen needleleaf forest. Spatial difference in NPP between different forest types was remarkable. High NPP values of deciduous needleleaf forest, mixed broadleaf- needleleaf forest and deciduous broadleaf forest were found in the Daxing’anling region, the southeastern of Xiaoxing’anling and Jilin province, and the Changbai Mountain, respectively. However, no regional differences were found for evergreen needleleaf NPP. This study provided not only an estimation NPP of different forest types in northeastern China but also a useful methodology for estimating forest carbon storage

  7. Evaluating spatial-temporal dynamics of net primary productivity of different forest types in northeastern China based on improved FORCCHN.

    PubMed

    Zhao, Junfang; Yan, Xiaodong; Guo, Jianping; Jia, Gensuo

    2012-01-01

    An improved individual-based forest ecosystem carbon budget model for China (FORCCHN) was applied to investigate the spatial-temporal dynamics of net primary productivity of different forest types in northeastern China. In this study, the forests of northeastern China were categorized into four ecological types according to their habitats and generic characteristics (evergreen broadleaf forest, deciduous broadleaf forest, evergreen needleleaf forest and deciduous needleleaf forest). The results showed that distribution and change of forest NPP in northeastern China were related to the different forest types. From 1981 to 2002, among the forest types in northeastern China, per unit area NPP and total NPP of deciduous broadleaf forest were the highest, with the values of 729.4 gC/(m(2)•yr) and 106.0 TgC/yr, respectively, followed by mixed broadleaf- needleleaf forest, deciduous needleleaf forest and evergreen needleleaf forest. From 1981 to 2002, per unit area NPP and total NPP of different forest types in northeastern China exhibited significant trends of interannual increase, and rapid increase was found between the 1980s and 1990s. The contribution of the different forest type's NPP to total NPP in northeastern China was clearly different. The greatest was deciduous broadleaf forest, followed by mixed broadleaf- needleleaf forest and deciduous needleleaf forest. The smallest was evergreen needleleaf forest. Spatial difference in NPP between different forest types was remarkable. High NPP values of deciduous needleleaf forest, mixed broadleaf- needleleaf forest and deciduous broadleaf forest were found in the Daxing'anling region, the southeastern of Xiaoxing'anling and Jilin province, and the Changbai Mountain, respectively. However, no regional differences were found for evergreen needleleaf NPP. This study provided not only an estimation NPP of different forest types in northeastern China but also a useful methodology for estimating forest carbon storage at

  8. Sediment Production from Forest Roads During Different Rainfall Conditions

    NASA Astrophysics Data System (ADS)

    Kunz, M. J.; Sullivan, K.; Dhakal, A. S.

    2004-12-01

    Sediment productions from storm-proofed forest roads were investigated at four locations in the managed forested land of Northwestern California (annual rainfall @1000 mm), where rocks have been characterized as Wildcat group consisting of mudstone, siltstone, claystone, and minor conglomerate. Rocked road (storm-proofed road) constitutes a part of the effective road management practices in the study area where other management practices include disconnection of roads from watercourses, reduction in distance between culverts, frequent road maintenance, and seasonal (or during rainfall) restrictions of log traffic. Specifically, this study examines the influence of rainstorm and road characteristics on sediment production from storm-proofed road in the context of varieties of road management practices in place. Continuous ditch flow during the rainstorm events was monitored using an UNIDATA float device and data logger. An ISCO sampler collected suspended sediment at temporal resolution of 2-h during the rainstorm events, and collected sediment samples were analyzed for turbidity and suspended sediment concentration in the laboratory. Sediment samples were also collected for particle size distribution analysis. Two tipping bucket rain gages located in the vicinity of road sites collected rainfall. Using an electronic total station, road surface was surveyed in detail, and a road Digital Elevation Model (DEM) was generated. Thus produced DEM was processed to delineate the road surface area contributing to ditch flow. The analysis of collected data for rainstorm events of hydrological year 2003/2004 reveals that the suspended sediment concentration conforms closely to rainfall hyetograph and ditch flow hydrograph with rapid flushing of road sediments for about 15-h following the onset of rainstorm. In general, ditch flow and suspended sediment concentration relation illustrates that the sediment transport is evidently "supply limited". For this reason, suspended

  9. Regional assessment of boreal forest productivity using an ecological process model and remote sensing parameter maps.

    PubMed

    Kimball, J. S.; Keyser, A. R.; Running, S. W.; Saatchi, S. S.

    2000-06-01

    An ecological process model (BIOME-BGC) was used to assess boreal forest regional net primary production (NPP) and response to short-term, year-to-year weather fluctuations based on spatially explicit, land cover and biomass maps derived by radar remote sensing, as well as soil, terrain and daily weather information. Simulations were conducted at a 30-m spatial resolution, over a 1205 km(2) portion of the BOREAS Southern Study Area of central Saskatchewan, Canada, over a 3-year period (1994-1996). Simulations of NPP for the study region were spatially and temporally complex, averaging 2.2 (+/- 0.6), 1.8 (+/- 0.5) and 1.7 (+/- 0.5) Mg C ha(-1) year(-1) for 1994, 1995 and 1996, respectively. Spatial variability of NPP was strongly controlled by the amount of aboveground biomass, particularly photosynthetic leaf area, whereas biophysical differences between broadleaf deciduous and evergreen coniferous vegetation were of secondary importance. Simulations of NPP were strongly sensitive to year-to-year variations in seasonal weather patterns, which influenced the timing of spring thaw and deciduous bud-burst. Reductions in annual NPP of approximately 17 and 22% for 1995 and 1996, respectively, were attributed to 3- and 5-week delays in spring thaw relative to 1994. Boreal forest stands with greater proportions of deciduous vegetation were more sensitive to the timing of spring thaw than evergreen coniferous stands. Similar relationships were found by comparing simulated snow depth records with 10-year records of aboveground NPP measurements obtained from biomass harvest plots within the BOREAS region. These results highlight the importance of sub-grid scale land cover complexity in controlling boreal forest regional productivity, the dynamic response of the biome to short-term interannual climate variations, and the potential implications of climate change and other large-scale disturbances. PMID:12651512

  10. Responses of soil buffering capacity to acid treatment in three typical subtropical forests.

    PubMed

    Jiang, Jun; Wang, Ying-Ping; Yu, Mengxiao; Li, Kun; Shao, Yijing; Yan, Junhua

    2016-09-01

    Elevated anthropogenic acid deposition can significantly affect forest ecosystem functioning by changing soil pH, nutrient balance, and chemical leaching and so on. These effects generally differ among different forests, and the dominant mechanisms for those observed responses often vary, depending on climate, soil conditions and vegetation types. Using soil monoliths (0-40cm) from pine forest (pioneer), coniferous and broadleaved mixed forest (transitional) and broadleaved forest (mature) in southern China, we conducted a leaching experiment with acid treatments at different pH levels (control: pH≈4.5; pH=3.5; pH=2.5). We found that pH3.5 treatment significantly reduced dissolved organic carbon (DOC) concentrations in leachate from the pioneer forest soil. pH2.5 treatment significantly increased concentrations of NO3(-), SO4(2-), Ca(2+), Mg(2+), Al(3+), Fe(3+) and DOC in leachate from the pioneer forest soil, and also concentrations of NO3(-), SO4(2-), Mg(2+), Al(3+), Fe(3+) and DOC in leachate from the transitional forest soil. All acid treatments had no significant effects on concentrations of these chemicals in leachate from the mature forest soil. The responses can be explained by the changes in soil pH, acid neutralizing capacity (ANC) and concentrations of Al and Fe. Our results showed that acid buffering capacity of the pioneer or transitional forest soil was lower than that of the mature forest soil. Therefore preserving mature forests in southern China is important for reducing the adverse impacts of high acid deposition on stream water quality at present and into the future. PMID:27185346

  11. Declining water yield from forested mountain watersheds in response to climate change and forest mesophication.

    PubMed

    Caldwell, Peter V; Miniat, Chelcy F; Elliott, Katherine J; Swank, Wayne T; Brantley, Steven T; Laseter, Stephanie H

    2016-09-01

    Climate change and forest disturbances are threatening the ability of forested mountain watersheds to provide the clean, reliable, and abundant fresh water necessary to support aquatic ecosystems and a growing human population. Here, we used 76 years of water yield, climate, and field plot vegetation measurements in six unmanaged, reference watersheds in the southern Appalachian Mountains of North Carolina, USA to determine whether water yield has changed over time, and to examine and attribute the causal mechanisms of change. We found that annual water yield increased in some watersheds from 1938 to the mid-1970s by as much as 55%, but this was followed by decreases up to 22% by 2013. Changes in forest evapotranspiration were consistent with, but opposite in direction to the changes in water yield, with decreases in evapotranspiration up to 31% by the mid-1970s followed by increases up to 29% until 2013. Vegetation survey data showed commensurate reductions in forest basal area until the mid-1970s and increases since that time accompanied by a shift in dominance from xerophytic oak and hickory species to several mesophytic species (i.e., mesophication) that use relatively more water. These changes in forest structure and species composition may have decreased water yield by as much as 18% in a given year since the mid-1970s after accounting for climate. Our results suggest that changes in climate and forest structure and species composition in unmanaged forests brought about by disturbance and natural community dynamics over time can result in large changes in water supply. PMID:27038309

  12. Response to CO2 enrichment of understory vegetation in the shade of forests.

    PubMed

    Kim, Dohyoung; Oren, Ram; Qian, Song S

    2016-02-01

    Responses of forest ecosystems to increased atmospheric CO2 concentration have been studied in few free-air CO2 enrichment (FACE) experiments during last two decades. Most studies focused principally on the overstory trees with little attention given to understory vegetation. Despite its small contribution to total productivity of an ecosystem, understory vegetation plays an important role in predicting successional dynamics and future plant community composition. Thus, the response of understory vegetation in Pinus taeda plantation at the Duke Forest FACE site after 15-17 years of exposure to elevated CO2 , 6-13 of which with nitrogen (N) amendment, was examined. Aboveground biomass and density of the understory decreased across all treatments with increasing overstory leaf area index (LAI). However, the CO2 and N treatments had no effect on aboveground biomass, tree density, community composition, and the fraction of shade-tolerant species. The increases of overstory LAI (~28%) under elevated CO2 resulted in a reduction of light available to the understory (~18%) sufficient to nullify the expected growth-enhancing effect of elevated CO2 on understory vegetation. PMID:26463669

  13. Decadal drought deaccelerated the increasing trend of annual net primary production in tropical or subtropical forests in southern China.

    PubMed

    Wang, Wantong; Wang, Jinxia; Liu, Xingzhao; Zhou, Guoyi; Yan, Junhua

    2016-01-01

    Previous investigations have identified that the effects of climate change on net primary production (NPP) of global forests have varied both spatially and temporally, and that warming has increased the NPP for many forests. However, other factors, such as available soil water for plant growth, could limit these incremental responses to warming. In our investigation we have quantified the responses of NPP of tropical or subtropical forests in southern China to warming and drought stress over the past three decades (1981 to 2012) using data from five forest research stations and satellite measurements. NPP, mean annual temperature (MAT) and annual days without rainfall showed an increase of 0.076 g C m(-2) a(-2) (standardized), 0.057 °C a(-1) (standardized) and 0.067 d a(-1) (standardized) during the study period, respectively. However, incremental NPP was deaccelerated at a rate of approximately 20.8% per decade. This deacceleration was primarily caused by a decrease in available soil water which resulted from warming (mainly occurring in winter and autumn) and the changes in rainfall pattern. The result indicates that intensifying drought stress would limit future increases of forest NPP in southern China. PMID:27356766

  14. Decadal drought deaccelerated the increasing trend of annual net primary production in tropical or subtropical forests in southern China

    PubMed Central

    Wang, Wantong; Wang, Jinxia; Liu, Xingzhao; Zhou, Guoyi; Yan, Junhua

    2016-01-01

    Previous investigations have identified that the effects of climate change on net primary production (NPP) of global forests have varied both spatially and temporally, and that warming has increased the NPP for many forests. However, other factors, such as available soil water for plant growth, could limit these incremental responses to warming. In our investigation we have quantified the responses of NPP of tropical or subtropical forests in southern China to warming and drought stress over the past three decades (1981 to 2012) using data from five forest research stations and satellite measurements. NPP, mean annual temperature (MAT) and annual days without rainfall showed an increase of 0.076 g C m−2 a−2 (standardized), 0.057 °C a−1 (standardized) and 0.067 d a−1 (standardized) during the study period, respectively. However, incremental NPP was deaccelerated at a rate of approximately 20.8% per decade. This deacceleration was primarily caused by a decrease in available soil water which resulted from warming (mainly occurring in winter and autumn) and the changes in rainfall pattern. The result indicates that intensifying drought stress would limit future increases of forest NPP in southern China. PMID:27356766

  15. Decadal drought deaccelerated the increasing trend of annual net primary production in tropical or subtropical forests in southern China

    NASA Astrophysics Data System (ADS)

    Wang, Wantong; Wang, Jinxia; Liu, Xingzhao; Zhou, Guoyi; Yan, Junhua

    2016-06-01

    Previous investigations have identified that the effects of climate change on net primary production (NPP) of global forests have varied both spatially and temporally, and that warming has increased the NPP for many forests. However, other factors, such as available soil water for plant growth, could limit these incremental responses to warming. In our investigation we have quantified the responses of NPP of tropical or subtropical forests in southern China to warming and drought stress over the past three decades (1981 to 2012) using data from five forest research stations and satellite measurements. NPP, mean annual temperature (MAT) and annual days without rainfall showed an increase of 0.076 g C m‑2 a‑2 (standardized), 0.057 °C a‑1 (standardized) and 0.067 d a‑1 (standardized) during the study period, respectively. However, incremental NPP was deaccelerated at a rate of approximately 20.8% per decade. This deacceleration was primarily caused by a decrease in available soil water which resulted from warming (mainly occurring in winter and autumn) and the changes in rainfall pattern. The result indicates that intensifying drought stress would limit future increases of forest NPP in southern China.

  16. Convergent structural responses of tropical forests to diverse disturbance regimes.

    PubMed

    Kellner, James R; Asner, Gregory P

    2009-09-01

    Size frequency distributions of canopy gaps are a hallmark of forest dynamics. But it remains unknown whether legacies of forest disturbance are influencing vertical size structure of landscapes, or space-filling in the canopy volume. We used data from LiDAR remote sensing to quantify distributions of canopy height and sizes of 434,501 canopy gaps in five tropical rain forest landscapes in Costa Rica and Hawaii. The sites represented a wide range of variation in structure and natural disturbance history, from canopy gap dynamics in lowland Costa Rica and Hawaii, to stages and types of stand-level dieback on upland Mauna Kea and Kohala volcanoes. Large differences in vertical canopy structure characterized these five tropical rain forest landscapes, some of which were related to known disturbance events. Although there were quantitative differences in the values of scaling exponents within and among sites, size frequency distributions of canopy gaps followed power laws at all sites and in all canopy height classes. Scaling relationships in gap size at different heights in the canopy were qualitatively similar at all sites, revealing a remarkable similarity despite clearly defined differences in species composition and modes of prevailing disturbance. These findings indicate that power-law gap-size frequency distributions are ubiquitous features of these five tropical rain forest landscapes, and suggest that mechanisms of forest disturbance may be secondary to other processes in determining vertical and horizontal size structure in canopies. PMID:19614757

  17. Leaf dynamics of a deciduous forest canopy: no response to elevated CO2.

    PubMed

    Norby, Richard J; Sholtis, Johnna D; Gunderson, Carla A; Jawdy, Sara S

    2003-08-01

    Leaf area index (LAI) and its seasonal dynamics are key determinants of terrestrial productivity and, therefore, of the response of ecosystems to a rising atmospheric CO(2) concentration. Despite the central importance of LAI, there is very little evidence from which to assess how forest LAI will respond to increasing [CO(2)]. We assessed LAI and related leaf indices of a closed-canopy deciduous forest for 4 years in 25-m-diameter plots that were exposed to ambient or elevated CO(2) (542 ppm) in a free-air CO(2) enrichment (FACE) experiment. LAI of this Liquidambar styraciflua (sweetgum) stand was about 6 and was relatively constant year-to-year, including the 2 years prior to the onset of CO(2) treatment. LAI throughout the 1999-2002 growing seasons was assessed through a combination of data on photosynthetically active radiation (PAR) transmittance, mass of litter collected in traps, and leaf mass per unit area (LMA). There was no effect of [CO(2)] on any expression of leaf area, including peak LAI, average LAI, or leaf area duration. Canopy mass and LMA, however, were significantly increased by CO(2) enrichment. The hypothesized connection between light compensation point (LCP) and LAI was rejected because LCP was reduced by [CO(2)] enrichment only in leaves under full sun, but not in shaded leaves. Data on PAR interception also permitted calculation of absorbed PAR (APAR) and light use efficiency (LUE), which are key parameters connecting satellite assessments of terrestrial productivity with ecosystem models of future productivity. There was no effect of [CO(2)] on APAR, and the observed increase in net primary productivity in elevated [CO(2)] was ascribed to an increase in LUE, which ranged from 1.4 to 2.4 g MJ(-1). The current evidence seems convincing that LAI of non-expanding forest stands will not be different in a future CO(2)-enriched atmosphere and that increases in LUE and productivity in elevated [CO(2)] are driven primarily by functional responses

  18. Increases in nitrogen uptake rather than nitrogen-use efficiency support higher rates of temperate forest productivity under elevated CO2

    SciTech Connect

    Finzi, Adrien C; Norby, Richard J; Califapietra, Carlo; Gielen, Birgit; Iversen, Colleen M; Jackson, Robert B; Kubiske, Mark E; Childs, Joanne; Schlesinger, William H; Ceulemans, Reinhart

    2007-01-01

    Forest ecosystems are important sinks for rising concentrations of atmospheric CO2. In a previous data synthesis of four forest FACE experiments (1), forest net primary production (NPP) increased by 23 2% when the forests were grown under atmospheric concentrations of CO2 predicted for the latter half of this century. Because nitrogen (N) availability commonly limits forest productivity, more N must be taken up from the soil and/or the N already assimilated by trees must be used more efficiently to support high rates of forest productivity under elevated CO2. Biogeochemical models predict that increases in forest NPP under elevated CO2 in N-limited ecosystems result in a significant increase in N-use efficiency (NUE), and that additional uptake of N by trees under elevated CO2 is only possible in ecosystems where N is not limiting. Here, experimental evidence demonstrates that patterns of N uptake and NUE under elevated CO2 differed from that predicted by biogeochemical models. The uptake of N increased under elevated CO2 at the Rhinelander, Duke and Oak Ridge National Laboratory (ORNL) FACE sites, yet fertilization studies at the Duke and ORNL FACE sites showed that tree growth and forest NPP were strongly limited by N availability. By contrast, NUE increased under elevated CO2 only at the POP-EUROFACE site where fertilization studies showed that N was not limiting to tree growth. In reviewing data from the forest FACE experiments, we suggest that some combination of increasing fine root production, increased rates of soil organic matter (SOM) decomposition, and increased allocation of carbon (C) to mycorrhizal fungi is likely to account for greater N uptake under elevated CO2 at the forest FACE sites. To accurately forecast the response of forest ecosystems to rising concentrations of atmospheric CO2, biogeochemical models must be reformulated to allow C transfers belowground that result in additional N uptake under elevated CO2.

  19. Tree species richness promotes productivity in temperate forests through strong complementarity between species.

    PubMed

    Morin, Xavier; Fahse, Lorenz; Scherer-Lorenzen, Michael; Bugmann, Harald

    2011-12-01

    Understanding the link between biodiversity and ecosystem functioning (BEF) is pivotal in the context of global biodiversity loss. Yet, long-term effects have been explored only weakly, especially for forests, and no clear evidence has been found regarding the underlying mechanisms. We explore the long-term relationship between diversity and productivity using a forest succession model. Extensive simulations show that tree species richness promotes productivity in European temperate forests across a large climatic gradient, mostly through strong complementarity between species. We show that this biodiversity effect emerges because increasing species richness promotes higher diversity in shade tolerance and growth ability, which results in forests responding faster to small-scale mortality events. Our study generalises results from short-term experiments in grasslands to forest ecosystems and demonstrates that competition for light alone induces a positive effect of biodiversity on productivity, thus providing a new angle for explaining BEF relationships. PMID:21955682

  20. Is the water footprint an appropriate tool for forestry and forest products: the Fennoscandian case.

    PubMed

    Launiainen, Samuli; Futter, Martyn N; Ellison, David; Clarke, Nicholas; Finér, Leena; Högbom, Lars; Laurén, Ari; Ring, Eva

    2014-03-01

    The water footprint by the Water Footprint Network (WF) is an ambitious tool for measuring human appropriation and promoting sustainable use of fresh water. Using recent case studies and examples from water-abundant Fennoscandia, we consider whether it is an appropriate tool for evaluating the water use of forestry and forest-based products. We show that aggregating catchment level water consumption over a product life cycle does not consider fresh water as a renewable resource and is inconsistent with the principles of the hydrologic cycle. Currently, the WF assumes that all evapotranspiration (ET) from forests is a human appropriation of water although ET from managed forests in Fennoscandia is indistinguishable from that of unmanaged forests. We suggest that ET should not be included in the water footprint of rain-fed forestry and forest-based products. Tools for sustainable water management should always contextualize water use and water impacts with local water availability and environmental sensitivity. PMID:23420472

  1. New products made with lignocellulosic nanofibers from Brazilian amazon forest

    NASA Astrophysics Data System (ADS)

    Bufalino, L.; Mendes, L. M.; Tonoli, G. H. D.; Rodrigues, A.; Fonseca, A.; Cunha, P. I.; Marconcini, J. M.

    2014-08-01

    The biodiversity of the Amazon forest is undoubtedly rich; hence there is considerable variety of plant fibers regarding their morphological, chemical and structural properties. The legal exploration of the Brazilian Amazon is based on sustainable management techniques, but the generation of a relevant amount of plant wastes still cant be avoided. The correct destination of such materials is a challenge that Brazilian companies have to face. In this context, the National Council of Science and Technology (CNPq) promoted the creation of investigation nets on sustainability of Brazilian agribusiness. The Brazilian Net on Lignocellulosic Composites and Nanocomposites was then created, with partnership between several national and international research institutions. Until the moment, the results showed that Amazon plant fibers that are discarded as residues have great potential to nanofiber production. Nanopapers with considerable high mechanical and physical strength, proper opacity and great crystalline index were produced by using a clean and simple mechanical method. Those materials are candidates to several uses such as packaging, substrates transparent conductive films, gas barrier films, solar cells and e-papers.

  2. Natural products from forest resources for use as arthropod and fungal biocides.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Natural products from Pacific Northwest forest resources can offer alternatives to the use of synthetic pesticides in the control of both arthropods of public health concern and forest fungal pathogens. Tree heartwood extracts with high toxicity (low LC50) in preliminary brine shrimp bioassays were...

  3. Natural Products from Forest Resources for Use as Arthropod and Fungal Biocides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Natural products from Pacific Northwest forest resources can offer alternatives to the use of synthetic pesticides in the control of both arthropods of public health concern and forest fungal pathogens. Tree heartwood extracts with high toxicity (low LC50) in preliminary brine shrimp bioassays were...

  4. 3 CFR 8892 - Proclamation 8892 of October 19, 2012. National Forest Products Week, 2012

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., renewable bioenergy that puts us on the path toward a secure energy future. Meeting the economic, environmental, and energy challenges we face will require active forest management that promotes conservation... recognize the importance of products from our forests, the Congress, by Public Law 86-753 (36 U.S.C....

  5. Temporal stability in forest productivity increases with tree diversity due to asynchrony in species dynamics.

    PubMed

    Morin, Xavier; Fahse, Lorenz; de Mazancourt, Claire; Scherer-Lorenzen, Michael; Bugmann, Harald

    2014-12-01

    Theory predicts a positive relationship between biodiversity and stability in ecosystem properties, while diversity is expected to have a negative impact on stability at the species level. We used virtual experiments based on a dynamic simulation model to test for the diversity-stability relationship and its underlying mechanisms in Central European forests. First our results show that variability in productivity between stands differing in species composition decreases as species richness and functional diversity increase. Second we show temporal stability increases with increasing diversity due to compensatory dynamics across species, supporting the biodiversity insurance hypothesis. We demonstrate that this pattern is mainly driven by the asynchrony of species responses to small disturbances rather than to environmental fluctuations, and is only weakly affected by the net biodiversity effect on productivity. Furthermore, our results suggest that compensatory dynamics between species may enhance ecosystem stability through an optimisation of canopy occupancy by coexisting species. PMID:25212251

  6. Modeling Transient Response of Forests to Climate Change

    SciTech Connect

    Dale, Virginia H; Tharp, M Lynn; Lannom, Karen O.; Hodges, Donald G

    2010-01-01

    Our hypothesis is that a high diversity of dominant life forms in Tennessee forests conveys resilience to disturbance such as climate change. Because of uncertainty in climate change and their effects, three climate change scenarios for 2030 and 2080 from three General Circulation Models (GCMs) were used to simulate a range of potential climate conditions for the state. These climate changes derive from the Intergovernmental Panel on Climate Change (IPCC) A1B storyline that assumes rapid global economic growth. The precipitation and temperature projections from the three GCMs for 2030 and 2080 were related to changes in five ecological provinces using the monthly record of temperature and precipitation from 1980 to 1997 for each 1 km cell across the state as aggregated into the provinces. Temperatures are projected to increase in all ecological provinces in all months for all three GCMs for both 2030 and 2080. Precipitation differences from the long-term average are more complex but less striking. The forest ecosystem model LINKAGES was used to simulate conditions for five ecological provinces from 1989 to 2300. Average output projects changes in tree diversity and species composition in all ecological provinces in Tennessee with the greatest changes in the Southern Mixed Forest province. Projected declines in total tree biomass are followed by biomass recovery as species replacement occurs in stands. The Southern Mixed Forest province results in less diversity in dominant trees as well as lower overall biomass than projections for the other four provinces. The biomass and composition changes projected in this study differ from forest dynamics expected without climate change. These results suggest that biomass recovery following climate change is linked to dominant tree diversity in the southeastern forest of the US. The generality of this observation warrants further investigation, for it relates to ways that forest management may influence climate change effects.

  7. Normalizing Landsat and ASTER Data Using MODIS Data Products for Forest Change Detection

    NASA Technical Reports Server (NTRS)

    Gao, Feng; Masek, Jeffrey G.; Wolfe, Robert E.; Tan, Bin

    2010-01-01

    Monitoring forest cover and its changes are a major application for optical remote sensing. In this paper, we present an approach to integrate Landsat, ASTER and MODIS data for forest change detection. Moderate resolution (10-100m) images (e.g. Landsat and ASTER) acquired from different seasons and times are normalized to one "standard" date using MODIS data products as reference. The normalized data are then used to compute forest disturbance index for forest change detection. Comparing to the results from original data, forest disturbance index from the normalized images is more consistent spatially and temporally. This work demonstrates an effective approach for mapping forest change over a large area from multiple moderate resolution sensors on various acquisition dates.

  8. Inferring responses to climate dynamics from historical demography in neotropical forest lizards.

    PubMed

    Prates, Ivan; Xue, Alexander T; Brown, Jason L; Alvarado-Serrano, Diego F; Rodrigues, Miguel T; Hickerson, Michael J; Carnaval, Ana C

    2016-07-19

    We apply a comparative framework to test for concerted demographic changes in response to climate shifts in the neotropical lowland forests, learning from the past to inform projections of the future. Using reduced genomic (SNP) data from three lizard species codistributed in Amazonia and the Atlantic Forest (Anolis punctatus, Anolis ortonii, and Polychrus marmoratus), we first reconstruct former population history and test for assemblage-level responses to cycles of moisture transport recently implicated in changes of forest distribution during the Late Quaternary. We find support for population shifts within the time frame of inferred precipitation fluctuations (the last 250,000 y) but detect idiosyncratic responses across species and uniformity of within-species responses across forest regions. These results are incongruent with expectations of concerted population expansion in response to increased rainfall and fail to detect out-of-phase demographic syndromes (expansions vs. contractions) across forest regions. Using reduced genomic data to infer species-specific demographical parameters, we then model the plausible spatial distribution of genetic diversity in the Atlantic Forest into future climates (2080) under a medium carbon emission trajectory. The models forecast very distinct trajectories for the lizard species, reflecting unique estimated population densities and dispersal abilities. Ecological and demographic constraints seemingly lead to distinct and asynchronous responses to climatic regimes in the tropics, even among similarly distributed taxa. Incorporating such constraints is key to improve modeling of the distribution of biodiversity in the past and future. PMID:27432951

  9. Inferring responses to climate dynamics from historical demography in neotropical forest lizards

    PubMed Central

    Xue, Alexander T.; Brown, Jason L.; Alvarado-Serrano, Diego F.; Rodrigues, Miguel T.; Hickerson, Michael J.; Carnaval, Ana C.

    2016-01-01

    We apply a comparative framework to test for concerted demographic changes in response to climate shifts in the neotropical lowland forests, learning from the past to inform projections of the future. Using reduced genomic (SNP) data from three lizard species codistributed in Amazonia and the Atlantic Forest (Anolis punctatus, Anolis ortonii, and Polychrus marmoratus), we first reconstruct former population history and test for assemblage-level responses to cycles of moisture transport recently implicated in changes of forest distribution during the Late Quaternary. We find support for population shifts within the time frame of inferred precipitation fluctuations (the last 250,000 y) but detect idiosyncratic responses across species and uniformity of within-species responses across forest regions. These results are incongruent with expectations of concerted population expansion in response to increased rainfall and fail to detect out-of-phase demographic syndromes (expansions vs. contractions) across forest regions. Using reduced genomic data to infer species-specific demographical parameters, we then model the plausible spatial distribution of genetic diversity in the Atlantic Forest into future climates (2080) under a medium carbon emission trajectory. The models forecast very distinct trajectories for the lizard species, reflecting unique estimated population densities and dispersal abilities. Ecological and demographic constraints seemingly lead to distinct and asynchronous responses to climatic regimes in the tropics, even among similarly distributed taxa. Incorporating such constraints is key to improve modeling of the distribution of biodiversity in the past and future. PMID:27432951

  10. Emergent Patterns of Forest Biomass Production from Across and within a Micro-Network

    NASA Astrophysics Data System (ADS)

    Pederson, N.; Martin Benito, D.; Bishop, D. A.; Dawson, A.; Dietze, M.; Druckenbrod, D.; Dye, A.; Gonzalez, A. C.; Hessl, A. E.; Martin Fernandez, J.; McLachlan, J. S.; Paciorek, C. J.; Poulter, B.; Williams, J. W.

    2014-12-01

    Many factors drive short- and long-term trends in forest biomass production. Replication at multiple scales, from within individual trees up to continental scales, is necessary to determine factors of growth and at what scale they are most important. Here we report on patterns of biomass production from within and across a micro-network of three forests in the northeastern US. Each forest has different histories and species composition, but each is within a similar climatological setting, which gives insight on important factors of short- and long-term patterns of forest production. One emergent pattern is that two forests are showing a large uptick in production over the last decade. Coincident to this uptick, late-season biomass production is showing a significant increase, even among 150-200+ year old trees. The third forest experienced a severe ice storm in the early-Aughts that paused a three-decade trend of increasing production. In the least diverse forest, the most dominant species drives most of the annual to decadal trend in production. In the most diverse forest, no one species appears to be driving landscape-level production, yet the emergent pattern of production reflects not only drought and pluvial events, but the impact of invasive species and the ice storm. Variation in annual biomass production for most species is strongly related to annual variations in soil moisture. Interestingly at the species level, coherency of growth among yellow birch is lower in the oldest forest in which is it is common versus the youngest forest. Differences in coherency suggest different drivers operating at different scales. Growth of red maple is also driven by moisture, but competition appears to be driving a long-term decline of individuals below the canopy. The decline begins soon after a severe defoliation event. In this same forest, however, significant wetting and warming over the last two decades appears to have reduced some of the climatic constraints on red

  11. Multidimensional trade-offs in species responses to disturbance: implications for diversity in a subtropical forest.

    PubMed

    Uriarte, María; Clark, James S; Zimmerman, Jess K; Comita, Liza S; Forero-Montaña, Jimena; Thompson, Jill

    2012-01-01

    Species employ diverse strategies to cope with natural disturbance, but the importance of these strategies for maintaining tree species diversity in forests has been debated. Mechanisms that have the potential to promote tree species coexistence in the context of repeated disturbance include life history trade-offs in colonization and competitive ability or in species' ability to survive at low resource conditions and exploit the temporary resource-rich conditions often generated in the wake of disturbance (successional niche). Quantifying these trade-offs requires long-term forest monitoring and modeling. We developed a hierarchical Bayes model to investigate the strategies tree species employ to withstand and recover from hurricane disturbance and the life history trade-offs that may facilitate species coexistence in forests subject to repeated hurricane disturbance. Unlike previous approaches, our model accommodates temporal variation in process error and observations from multiple sources. We parameterized the model using growth and mortality data from four censuses of a 16-ha plot taken every five years (1990-2005), together with damage data collected after two hurricanes and annual seed production data (1992-2005). Species' susceptibilities to hurricane damage as reflected by changes in diameter growth and fecundity immediately following a storm were weak, highly variable, and unpredictable using traditional life history groupings. The lower crowding conditions (e.g., high light) generated in the wake of storms, however, led to greater gains in growth and fecundity for pioneer and secondary-forest species than for shade-tolerant species, in accordance with expectation of life history. We found moderate trade-offs between survival in high crowding conditions, a metric of competitive ability, and long-distance colonization. We also uncovered a strong trade-off between mean species fecundity in low crowding conditions, a metric of recovery potential, and

  12. Ecosystem Disturbance Effects on Land Surface Temperature, Forest Carbon Stocks, and Primary Productivity in the Western United States

    NASA Astrophysics Data System (ADS)

    Cooper, L. A.; Ballantyne, A.; Holden, Z. A.; Landguth, E.

    2015-12-01

    Disturbance plays an important role in the structure, composition, and nutrient cycling of forest ecosystems. Climate change is resulting in an increase in disturbance frequency and intensity, making it critical that we quantify the physical and chemical impacts of disturbances on forests. The impacts of disturbance are thought to vary widely depending on disturbance type, location, and climate. More specifically, fires, insect infestations, and other types of disturbances differ in their timing, extent, and intensity making it difficult to assess the true impact of disturbances on local energy budgets and carbon cycling. Here, we provide a regional analysis of the impacts of fire, insect attack, and other disturbances on land surface temperature (LST), carbon stocks, and gross primary productivity (GPP). Using disturbances detected with MODIS Enhanced Vegetation Index (EVI) time series between 2002 and 2012, we find that the impacts of disturbance on LST, carbon stocks, and GPP vary widely according to local climate, vegetation, and disturbance type and intensity. Fires resulted in the most distinct impacts on all response variables. Forest responses to insect epidemics were more varied in their magnitude and timing. The results of this study provide an important estimation of the variability of climate and ecosystem responses to disturbance across a large and heterogeneous landscape. With disturbance projected to increase in both frequency and intensity around the globe in the coming years, this information is vitally important to effectively manage forests into the future.

  13. Final Progress Report on Model-Based Diagnosis of Soil Limitations to Forest Productivity

    SciTech Connect

    Luxmoore, R.J.

    2004-08-30

    This project was undertaken in support of the forest industry to link modeling of nutrients and productivity with field research to identify methods for enhancing soil quality and forest productivity and for alleviating soil limitations to sustainable forest productivity. The project consisted of a series of related tasks, including (1) simulation of changes in biomass and soil carbon with nitrogen fertilization, (2) development of spreadsheet modeling tools for soil nutrient availability and tree nutrient requirements, (3) additional modeling studies, and (4) evaluation of factors involved in the establishment and productivity of southern pine plantations in seasonally wet soils. This report also describes the two Web sites that were developed from the research to assist forest managers with nutrient management of Douglas-fir and loblolly pine plantations.

  14. Interpreting forest and grassland biome productivity utilizing nested scales of image resolution and biogeographical analysis

    NASA Technical Reports Server (NTRS)

    Iverson, Louis R.; Cook, Elizabeth A.; Graham, Robin L.; Olson, Jerry S.; Frank, Thomas; Ke, Ying; Treworgy, Colin; Risser, Paul G.

    1987-01-01

    This report summarizes progress made in our investigation of forest productivity assessment using TM and other biogeographical data during the third six-month period of the grant. Data acquisition and methodology hurdles are largely complete. Four study areas for which the appropriate TM and ancillary data were available are currently being intensively analyzed. Significant relationships have been found on a site by site basis to suggest that forest productivity can be qualitatively assessed using TM band values and site characteristics. Perhaps the most promising results relate TM unsupervised classes to forest productivity, with enhancement from elevation data. During the final phases of the research, multi-temporal and regional comparisons of results will be addressed, as well as the predictability of forest productivity patterns over a large region using TM data and/or TM nested within AVHRR data.

  15. Fertilizer Response Curves for Commercial Southern Forest Species Defined with an Un-Replicated Experimental Design.

    SciTech Connect

    Coleman, Mark; Aubrey, Doug; Coyle, David, R.; Daniels, Richard, F.

    2005-11-01

    There has been recent interest in use of non-replicated regression experimental designs in forestry, as the need for replication in experimental design is burdensome on limited research budgets. We wanted to determine the interacting effects of soil moisture and nutrient availability on the production of various southeastern forest trees (two clones of Populus deltoides, open pollinated Platanus occidentalis, Liquidambar styraciflua and Pinus taeda). Additionally, we required an understanding of the fertilizer response curve. To accomplish both objectives we developed a composite design that includes a core ANOVA approach to consider treatment interactions, with the addition of non-replicated regression plots receiving a range of fertilizer levels for the primary irrigation treatment.

  16. Hydrologic response to forest cover changes following a Mountain Pine Beetle outbreak in the context of a changing climate

    NASA Astrophysics Data System (ADS)

    Moore, Dan; Jost, Georg; Nelson, Harry; Smith, Russell

    2013-04-01

    Over the last 15 years, there has been extensive mortality of pine forests in western North America associated with an outbreak of Mountain Pine Beetle, often followed by salvage logging. The objective of this study was to quantify the separate and combined effects of forest recovery and climate change over the 21st century on catchment hydrology in the San Jose watershed, located in the semi-arid Interior Plateau of British Columbia. Forest cover changes were simulated using a dynamic spatial model that uses a decentralized planning approach. We implemented management strategies representing current timber management objectives around achieving targeted harvest levels and incorporating existing management constraints under two different scenarios, one with no climate change and one under climate change, using climate-adjusted growth and yield curves. In addition, higher rates of fire disturbance were modelled under climate change. Under climate change, while productivity improves for some species (mainly Douglas-fir on better quality sites), on drier and poorer quality sites most species, especially Lodgepole Pine, become significantly less productive, and stocking is reduced to the point that those sites transition into grasslands. The combined effect of initial age classes (where the forest has been severely impacted by MPB), increased fire, and reduced stocking results in a greater proportion of the forest in younger age classes compared to a "Business As Usual" scenario with no climate change. The hydrologic responses to changes in vegetation cover and climate were evaluated with the flexible Hydrology Emulator and Modelling Platform (HEMP) developed at the University of British Columbia. HEMP allows a flexible discretization of the landscape. Water is moved vertically within landscape units by processes such as precipitation, canopy interception and soil infiltration, and routed laterally between units as a function of local soil and groundwater storage. The

  17. Acidic deposition and its effects on forest productivity: a review of the present state of knowledge, research activities, and information needs

    SciTech Connect

    Pinkerton, J.E.

    1981-01-01

    The present state of knowledge with regard to acid deposition is reviewed. Sources include the literature and direct contact with persons responsible for carrying out all completed, ongoing, and planned research activities, national and international, related to acidic deposition and its effects, with emphasis on forest productivity. In addition, a list of information needs in seven areas was developed, these include: a characterization of forest soils to define their sensitivity to acidic deposition; effects on forest soil chemical and biological processes; development of improved dry deposition measurement methods; changes in precipitation composition due to forest canopies; more extensive monitoring of acidic deposition in industry owned forest lands; expansion of long-term greenhouse and controlled field experiments; and the relationship of acidic deposition and intensive forestry management practices. 85 references. (MDF)

  18. Catchment hydrological responses to forest harvest amount and spatial pattern

    EPA Science Inventory

    Forest harvest effects on streamflow dynamics have been well described experimentally, but a clear understanding of process-level hydrological controls can be difficult to ascertain from data alone. We apply a new model, Visualizing Ecosystems for Land Management Assessments (VE...

  19. FORAST (FOREST RESPONSES TO ANTHROPOGENIC STRESS) DATA BASE DOCUMENTATION

    EPA Science Inventory

    The report has been prepared to (1) document the objectives, experimental design, and data collection protocols for a 3-year study of growth patterns of forest trees in the eastern U.S. and (2) describe how data derived from the study are stored and may be accessed from a magneti...

  20. Short and Long Term Impacts of Forest Bioenergy Production on Atmospheric Carbon Dioxide Emissions

    NASA Astrophysics Data System (ADS)

    Hudiburg, T.; Law, B. E.; Luyssaert, S.; Thornton, P. E.

    2011-12-01

    Temperate forest annual net uptake of CO2 from the atmosphere is equivalent to ~16% of the annual fossil fuel emissions in the United States. Mitigation strategies to reduce emissions of carbon dioxide have lead to investigation of alternative sources of energy including forest biomass. The prospect of forest derived bioenergy has led to implementation of new forest management strategies based on the assumption that they will reduce total CO2 emissions to the atmosphere by simultaneously reducing the risk of wildfire and substituting for fossil fuels. The benefit of managing forests for bioenergy substitution of fossil fuels versus potential carbon sequestration by reducing harvest needs to be evaluated. This study uses a combination of Federal Forest Inventory data (FIA), remote sensing, and a coupled carbon-nitrogen ecosystem process model (CLM4-CN) to predict net atmospheric CO2 emissions from forest thinning for bioenergy production in Oregon under varying future management and climate scenarios. We use life-cycle assessment (LCA) incorporating both the forest and forest product sinks and sources of carbon dioxide. Future modeled results are compared with a reduced harvest scenario to determine the potential for increased carbon sequestration in forest biomass. We find that Oregon forests are a current strong sink of 7.5 ± 1.7 Tg C yr-1 or 61 g C m-2 yr-1. (NBP; NEP minus removals from fire and harvest). In the short term, we find that carbon dynamics following harvests for fire prevention and large-scale bioenergy production lead to 2-15% higher emissions over the next 20 years compared to current management, assuming 100% effectiveness of fire prevention. Given the current sink strength, analysis of the forest sector in Oregon demonstrates that increasing harvest levels by all practices above current business-as-usual levels increases CO2 emissions to the atmosphere as long as the region's sink persists. In the long-term, we find that projected changes in

  1. Digging deeper: Fine root responses to rising atmospheric [CO2] in forested ecosystems

    SciTech Connect

    Iversen, Colleen M

    2010-01-01

    Experimental evidence from a diverse set of forested ecosystems indicates that CO2 enrichment may lead to deeper rooting distributions. While the causes of greater root production at deeper soil depths under elevated CO2 concentration ([CO2]) require further investigation, altered rooting distributions are expected to affect important ecosystem processes. The depth at which fine roots are produced may influence root chemistry, physiological function, and mycorrhizal infection, leading to altered nitrogen (N) uptake rates and slower turnover. Also, soil processes such as microbial decomposition are slowed at depth in the soil, potentially affecting the rate at which root detritus becomes incorporated into soil organic matter. Deeper rooting distributions under elevated [CO2] provide exciting opportunities to use novel sensors and chemical analyses throughout the soil profile to track the effects of root proliferation on carbon (C) and N cycling. Models do not currently incorporate information on root turnover and C and N cycling at depth in the soil, and modification is necessary to accurately represent processes associated with altered rooting depth distributions. Progress in understanding and modeling the interface between deeper rooting distributions under elevated [CO2] and soil C and N cycling will be critical in projecting the sustainability of forest responses to rising atmospheric [CO2].

  2. Diverse growth trends and climate responses across Eurasia’s boreal forest

    NASA Astrophysics Data System (ADS)

    Hellmann, Lena; Agafonov, Leonid; Charpentier Ljungqvist, Fredrik; Churakova (Sidorova, Olga; Düthorn, Elisabeth; Esper, Jan; Hülsmann, Lisa; Kirdyanov, Alexander V.; Moiseev, Pavel; Myglan, Vladimir S.; Nikolaev, Anatoly N.; Reinig, Frederick; Schweingruber, Fritz H.; Solomina, Olga; Tegel, Willy; Büntgen, Ulf

    2016-07-01

    The area covered by boreal forests accounts for ∼16% of the global and 22% of the Northern Hemisphere landmass. Changes in the productivity and functioning of this circumpolar biome not only have strong effects on species composition and diversity at regional to larger scales, but also on the Earth’s carbon cycle. Although temporal inconsistency in the response of tree growth to temperature has been reported from some locations at the higher northern latitudes, a systematic dendroecological network assessment is still missing for most of the boreal zone. Here, we analyze the geographical patterns of changes in summer temperature and precipitation across northern Eurasia >60 °N since 1951 AD, as well as the growth trends and climate responses of 445 Pinus, Larix and Picea ring width chronologies in the same area and period. In contrast to widespread summer warming, fluctuations in precipitation and tree growth are spatially more diverse and overall less distinct. Although the influence of summer temperature on ring formation is increasing with latitude and distinct moisture effects are restricted to a few southern locations, growth sensitivity to June–July temperature variability is only significant at 16.6% of all sites (p ≤ 0.01). By revealing complex climate constraints on the productivity of Eurasia’s northern forests, our results question the a priori suitability of boreal tree-ring width chronologies for reconstructing summer temperatures. This study further emphasizes regional climate differences and their role on the dynamics of boreal ecosystems, and also underlines the importance of free data access to facilitate the compilation and evaluation of massively replicated and updated dendroecological networks.

  3. The ambiguity of drought events, a bottleneck for Amazon forest drought response modelling

    NASA Astrophysics Data System (ADS)

    De Deurwaerder, Hannes; Verbeeck, Hans; Baker, Timothy; Christoffersen, Bradley; Ciais, Philippe; Galbraith, David; Guimberteau, Matthieu; Kruijt, Bart; Langerwisch, Fanny; Meir, Patrick; Rammig, Anja; Thonicke, Kirsten; Von Randow, Celso; Zhang, Ke

    2016-04-01

    Considering the important role of the Amazon forest in the global water and carbon cycle, the prognosis of altered hydrological patterns resulting from climate change provides strong incentive for apprehending the direct implications of drought on the vegetation of this ecosystem. Dynamic global vegetation models have the potential of providing a useful tool to study drought impacts on various spatial and temporal scales. This however assumes the models being able to properly represent drought impact mechanisms. But how well do the models succeed in meeting this assumption? Within this study meteorological driver data and model output data of 4 different DGVMs, i.e. ORCHIDEE, JULES, INLAND and LPGmL, are studied. Using the palmer drought severity index (PDSI) and the mean cumulative water deficit (MWD), temporal and spatial representation of drought events are studied in the driver data and are referenced to historical extreme drought events in the Amazon. Subsequently, within the resulting temporal and spatial frame, we studied the drought impact on the above ground biomass (AGB) and gross primary production (GPP) fluxes. Flux tower data, field inventory data and the JUNG data-driven GPP product for the Amazon region are used for validation. Our findings not only suggest that the current state of the studied DGVMs is inadequate in representing Amazon droughts in general, but also highlights strong inter-model differences in drought responses. Using scatterplot-studies and input-output correlations, we provide insight in the origin of these encountered inter-model differences. In addition, we present directives of model development and improvement in scope of Amazon forest drought response modelling.

  4. Leaf litter arthropod responses to tropical forest restoration.

    PubMed

    Cole, Rebecca J; Holl, Karen D; Zahawi, Rakan A; Wickey, Philipp; Townsend, Alan R

    2016-08-01

    Soil and litter arthropods represent a large proportion of tropical biodiversity and perform important ecosystem functions, but little is known about the efficacy of different tropical forest restoration strategies in facilitating their recovery in degraded habitats. We sampled arthropods in four 7- to 8-year-old restoration treatments and in nearby reference forests. Sampling was conducted during the wet and dry seasons using extractions from litter and pitfall samples. Restoration treatments were replicated in 50 × 50-m plots in four former pasture sites in southern Costa Rica: plantation - trees planted throughout the plot; applied nucleation/islands - trees planted in patches of different sizes; and natural regeneration - no tree planting. Arthropod abundance, measures of richness and diversity, and a number of functional groups were greater in the island treatment than in natural regeneration or plantation treatments and, in many cases, were similar to reference forest. Litter and pitfall morphospecies and functional group composition in all three restoration treatments were significantly different than reference sites, but island and plantation treatments showed more recovery than natural regeneration. Abundance and functional group diversity showed a much greater degree of recovery than community composition. Synthesis and applications: The less resource-intensive restoration strategy of planting tree islands was more effective than tree plantations in restoring arthropod abundance, richness, and functional diversity. None of the restoration strategies, however, resulted in similar community composition as reference forest after 8 years of recovery, highlighting the slow rate of recovery of arthropod communities after disturbance, and underscoring the importance of conservation of remnant forests in fragmented landscapes. PMID:27551373

  5. Modeling and spatially distributing forest net primary production at the regional scale.

    PubMed

    Mickler, Robert A; Earnhardt, Todd S; Moore, Jennifer A

    2002-04-01

    Forest, agricultural, rangeland, wetland, and urban landscapes have different rates of carbon sequestration and total carbon sequestration potential under alternative management options. Changes in the proportion and spatial distribution of land use could enhance or degrade that area's ability to sequester carbon in terrestrial ecosystems. As the ecosystems within a landscape change due to natural or anthropogenic processes, they may go from being a carbon sink to a carbon source or vice versa. Satellite image analysis has been tested for timely and accurate measurement of spatially explicit land use change and is well suited for use in inventory and monitoring of terrestrial carbon. The coupling of Landsat Thematic Mapper (TM) data with a physiologically based forest productivity model (PnET-II) and historic climatic data provides an opportunity to enhance field plot-based forest inventory and monitoring methodologies. We use periodic forest inventory data from the U.S. Department of Agriculture (USDA) Forest Service's Forest Inventory and Analysis (FIA) Program to obtain estimates of forest area and type and to generate estimates of carbon storage for evergreen, deciduous, and mixed-forest classes. The area information is used in an accuracy assessment of remotely sensed forest cover at the regional scale. The map display of modeled net primary production (NPP) shows a range of forest carbon storage potentials and their spatial relationship to other landscape features across the southern United States. This methodology addresses the potential for measuring and projecting forest carbon sequestration in the terrestrial biosphere of the southern United States. PMID:12002186

  6. Responses of soil fungi to logging and oil palm agriculture in Southeast Asian tropical forests.

    PubMed

    McGuire, K L; D'Angelo, H; Brearley, F Q; Gedallovich, S M; Babar, N; Yang, N; Gillikin, C M; Gradoville, R; Bateman, C; Turner, B L; Mansor, P; Leff, J W; Fierer, N

    2015-05-01

    Human land use alters soil microbial composition and function in a variety of systems, although few comparable studies have been done in tropical forests and tropical agricultural production areas. Logging and the expansion of oil palm agriculture are two of the most significant drivers of tropical deforestation, and the latter is most prevalent in Southeast Asia. The aim of this study was to compare soil fungal communities from three sites in Malaysia that represent three of the most dominant land-use types in the Southeast Asia tropics: a primary forest, a regenerating forest that had been selectively logged 50 years previously, and a 25-year-old oil palm plantation. Soil cores were collected from three replicate plots at each site, and fungal communities were sequenced using the Illumina platform. Extracellular enzyme assays were assessed as a proxy for soil microbial function. We found that fungal communities were distinct across all sites, although fungal composition in the regenerating forest was more similar to the primary forest than either forest community was to the oil palm site. Ectomycorrhizal fungi, which are important associates of the dominant Dipterocarpaceae tree family in this region, were compositionally distinct across forests, but were nearly absent from oil palm soils. Extracellular enzyme assays indicated that the soil ecosystem in oil palm plantations experienced altered nutrient cycling dynamics, but there were few differences between regenerating and primary forest soils. Together, these results show that logging and the replacement of primary forest with oil palm plantations alter fungal community and function, although forests regenerating from logging had more similarities with primary forests in terms of fungal composition and nutrient cycling potential. Since oil palm agriculture is currently the mostly rapidly expanding equatorial crop and logging is pervasive across tropical ecosystems, these findings may have broad applicability

  7. Fire severity influences the response of soil microbes to a boreal forest fire

    NASA Astrophysics Data System (ADS)

    Holden, Sandra R.; Rogers, Brendan M.; Treseder, Kathleen K.; Randerson, James T.

    2016-03-01

    Wildfire activity is projected to increase in boreal forests as a result of climate warming. The consequences of increased wildfire activity for soil carbon (C) storage in boreal forests may depend on the sensitivity of soil microbes to fire severity, but microbial responses to boreal forest fire severity are not well known. Here, we combine remote sensing of fire severity and field sampling to characterize the response of soil microbial biomass per g soil, microbial respiration of CO2 per g soil, and fungal groups to fire severity in a boreal forest ecosystem. We used remote sensing measurements of differenced normalized burn ratio from Landsat as a measure of fire severity. Our results demonstrate that fire severity controls soil microbial responses to boreal forest fires. In comparison to unburned stands, burned stands had a 52% and 56% reduction in soil microbial biomass and basal respiration, respectively. Within burned stands, we found that microbial biomass and basal respiration significantly declined with increasing fire severity. In addition, mycorrhizal taxa and basidiomycetes displayed particularly low tolerances for severe fire. Although wildfires result in the immediate loss of soil C, our study provides evidence that decreases in microbial biomass and respiration following high severity fires may reduce the capacity of the soil microbial community to decompose soil C over longer time scales. Therefore, models of C cycle responses to climate warming may need to represent the sensitivity of microbial biomass and fungal community composition to fire severity in boreal forests.

  8. Contrasting simulated past and future responses of the Amazonian forest to atmospheric change.

    PubMed Central

    Cowling, Sharon A; Betts, Richard A; Cox, Peter M; Ettwein, Virginia J; Jones, Chris D; Maslin, Mark A; Spall, Steven A

    2004-01-01

    Modelling simulations of palaeoclimate and past vegetation form and function can contribute to global change research by constraining predictions of potential earth system responses to future warming, and by providing useful insights into the ecophysiological tolerances and threshold responses of plants to varying degrees of atmospheric change. We contrasted HadCM3LC simulations of Amazonian forest at the last glacial maximum (LGM; 21 kyr ago) and a Younger Dryas-like period (13-12 kyr ago) with predicted responses of future warming to provide estimates of the climatic limits under which the Amazon forest remains relatively stable. Our simulations indicate that despite lower atmospheric CO2 concentrations and increased aridity during the LGM, Amazonia remains mostly forested, and that the cooling climate of the Younger Dryas-like period in fact causes a trend toward increased above-ground carbon balance relative to today. The vegetation feedbacks responsible for maintaining forest integrity in past climates (i.e. decreased evapotranspiration and reduced plant respiration) cannot be maintained into the future. Although elevated atmospheric CO2 contributes to a positive enhancement of plant carbon and water balance, decreased stomatal conductance and increased plant and soil respiration cause a positive feedback that amplifies localized drying and climate warming. We speculate that the Amazonian forest is currently near its critical resiliency threshold, and that even minor climate warming may be sufficient to promote deleterious feedbacks on forest integrity. PMID:15212101

  9. Different soil respiration responses to litter manipulation in three subtropical successional forests

    NASA Astrophysics Data System (ADS)

    Han, Tianfeng; Huang, Wenjuan; Liu, Juxiu; Zhou, Guoyi; Xiao, Yin

    2015-12-01

    Aboveground litter inputs have been greatly altered by human disturbances and climate change, which have important effects on soil respiration. However, the knowledge of how soil respiration responds to altered litter inputs is limited in tropical and subtropical forests. We conducted an aboveground litterfall manipulation experiment in three successional forests in the subtropics to examine the soil respiration responses to different litter inputs from January 2010 to July 2012. The soil respiration decreased by 35% in the litter exclusion treatments and increased by 77% in the doubled litter additions across all three forests. The reduction in soil respiration induced by the litter exclusion was greatest in the early successional forest, which may be related to a decrease in the soil moisture and shifts in the microbial community. The increase in soil respiration produced by the doubled litter addition was largest in the mature forest, which was most probably due to its relatively high quantity and quality of litterfall. Our results suggest that the effect of reduced litter inputs on the soil respiration lessened with forest succession but that the doubled litter inputs resulted in a stronger priming effect in the mature forest than in the other two forests.

  10. Different soil respiration responses to litter manipulation in three subtropical successional forests

    PubMed Central

    Han, Tianfeng; Huang, Wenjuan; Liu, Juxiu; Zhou, Guoyi; Xiao, Yin

    2015-01-01

    Aboveground litter inputs have been greatly altered by human disturbances and climate change, which have important effects on soil respiration. However, the knowledge of how soil respiration responds to altered litter inputs is limited in tropical and subtropical forests. We conducted an aboveground litterfall manipulation experiment in three successional forests in the subtropics to examine the soil respiration responses to different litter inputs from January 2010 to July 2012. The soil respiration decreased by 35% in the litter exclusion treatments and increased by 77% in the doubled litter additions across all three forests. The reduction in soil respiration induced by the litter exclusion was greatest in the early successional forest, which may be related to a decrease in the soil moisture and shifts in the microbial community. The increase in soil respiration produced by the doubled litter addition was largest in the mature forest, which was most probably due to its relatively high quantity and quality of litterfall. Our results suggest that the effect of reduced litter inputs on the soil respiration lessened with forest succession but that the doubled litter inputs resulted in a stronger priming effect in the mature forest than in the other two forests. PMID:26656136

  11. Different soil respiration responses to litter manipulation in three subtropical successional forests.

    PubMed

    Han, Tianfeng; Huang, Wenjuan; Liu, Juxiu; Zhou, Guoyi; Xiao, Yin

    2015-01-01

    Aboveground litter inputs have been greatly altered by human disturbances and climate change, which have important effects on soil respiration. However, the knowledge of how soil respiration responds to altered litter inputs is limited in tropical and subtropical forests. We conducted an aboveground litterfall manipulation experiment in three successional forests in the subtropics to examine the soil respiration responses to different litter inputs from January 2010 to July 2012. The soil respiration decreased by 35% in the litter exclusion treatments and increased by 77% in the doubled litter additions across all three forests. The reduction in soil respiration induced by the litter exclusion was greatest in the early successional forest, which may be related to a decrease in the soil moisture and shifts in the microbial community. The increase in soil respiration produced by the doubled litter addition was largest in the mature forest, which was most probably due to its relatively high quantity and quality of litterfall. Our results suggest that the effect of reduced litter inputs on the soil respiration lessened with forest succession but that the doubled litter inputs resulted in a stronger priming effect in the mature forest than in the other two forests. PMID:26656136

  12. Eroding forest carbon sinks following thinning for combined fire prevention and bioenergy production

    NASA Astrophysics Data System (ADS)

    Hudiburg, T. W.; Law, B. E.; Luyssaert, S.

    2010-12-01

    Temperate forest annual net uptake of CO2 from the atmosphere is equivalent to ~16% of the annual fossil fuel emissions in the United States. Mitigation strategies to reduce emissions of carbon dioxide have lead to investigation of alternative sources of energy including forest biomass. The prospect of forest derived bioenergy has led to implementation of new forest management strategies based on the assumption that they will reduce total CO2 emissions to the atmosphere by simultaneously reducing the risk of wildfire and substituting for fossil fuels. Using Forest Inventory Analysis (FIA) plot data, regional supplemental plot data, and remote sensing products we determined the carbon stocks and fluxes of West Coast forests under current and proposed management scenarios for a 20 year treatment period. Varying biofuels thinning treatments designed to meet multiple objectives emphasizing fire prevention, economic gain, or energy production were applied to determine the resulting net carbon balance and bioenergy potential. Contrary to the management objectives, we find that increased removals result in substantial decreases in forest carbon stocks and Net Biome Production (NBP) and increased emissions. Thinning forests for energy production is not carbon neutral. Emissions are estimated to increase over the 20-year period because preventive thinning removals exceed the CO2 that would have been emitted due to wildfires, fossil fuel inputs are required for harvest and manufacturing, and use of woody biomass in short-lived products emits large quantities of CO2 to the atmosphere. It has the net effect of releasing otherwise sequestered carbon to the atmosphere, which may effectively reduce ongoing carbon uptake by forests and as a result, increase net greenhouse gas emissions, undermining the objective of greenhouse gas reductions over the next several decades.

  13. Long-term successional forest dynamics: species and community responses to climatic variability

    SciTech Connect

    Kardol, Paul; Todd Jr, Donald E; Hanson, Paul J; Mulholland, Patrick J

    2010-01-01

    Question: Are tree dynamics sensitive to climatic variability, and do tree species differ in their responses to climatic variability? Hence, is vulnerability of forest communities to climatic variability depending on stand composition? Location: Mixed young forest at Walker Branch Watershed near Oak Ridge, East-Tennessee, USA. Methods: Using a long-term data set (1967-2006), we analyzed temporal forest dynamics at the tree and species level, and we analyzed community dynamics for forest stands that different in their initial species composition (i.e., Chestnut Oak, Oak-Hickory, Pine, and Yellow poplar stands). Using summer drought and growing season temperature as defined climate drivers, we evaluated relationships between forest dynamics and climate across levels of organization. Results: Over the 4-decade studied period, forest communities underwent successional change and substantially increased their biomass. Variation in summer drought and growing season temperature contributed to temporal biomass dynamics for some tree species, but not for others. Stand-level responses to climatic variability were shown to be related to responses of specific component species; however, not for Pine stands. Pinus echinata, the dominant species in stands initially identified as Pine stands, decreased over time due to periodical outbreaks of the pine bark beetle (Dendroctonus frontalis). The outbreaks on Walker Branch could not be directly related to climatic conditions. Conclusions: Our results imply that vulnerability of developing forests to predicted climate conditions is stand-type dependent, and hence, is a function of species composition. Autogenic successional processes (or insect outbreaks) were found to prevail over climatic variability in determining long-term forest dynamics for stands dominated by sensitive species, emphasizing the importance of studying interactions between forest succession and climate change.

  14. Comparison of NASA OMI and MLS Ozone Products with US Forest Service Ground-based Ozone Monitoring Data for US Forest Service Air Quality / Forest Management Decision Support

    NASA Astrophysics Data System (ADS)

    Barrett, S.; Brooks, A.; Moussa, Y.; Spencer, T.; Thompson, J.

    2013-12-01

    Tropospheric ozone, formed when nitrogen oxides (NOx) and volatile organic compounds (VOCs) react with sunlight, is a significant threat to the health of US National Forests. Approximately one third of ozone is absorbed by plants during the uptake of carbon dioxide. This increases the vegetation's susceptibility to drought, beetle infestation, and wildfire. Currently the US Forest Service has ground monitoring stations sparsely located across the country. This project looks specifically at the area surrounding several Class I Wilderness Areas in the Appalachian region. These areas are the highest priority for protection from air pollutants. The Forest Service must interpolate ozone concentrations for areas between these monitoring stations. Class I Wilderness Areas are designated by the Forest Service and are defined as a total 5000 acres or greater when the Clean Air Act was passed in 1977. This Act mandated that the EPA create national ambient air quality standards (NAAQS) for six major air pollutants including ground-level ozone. This project assessed the feasibility of incorporating NASA ozone data into Forest Service ozone monitoring in an effort to enhance the accuracy and precision of ozone exposure measurements in Class I Wilderness Areas and other federally managed lands in order to aid in complying with the Clean Air Act of 1977. This was accomplished by establishing a method of comparison between a preliminary data product produced at the Goddard Space Flight Center that uses OMI/MLS data to derive global tropospheric ozone measurements and Forest Service ozone monitoring station measurements. Once a methodology for comparison was established, statistical comparisons of these data were performed to assess the quantitative differences.

  15. Responses of endoparasites in red-backed voles (Myodes gapperi) to natural forest fires.

    PubMed

    Hwang, Y T; Gardner, S L; Millar, J S

    2010-01-01

    We investigated the responses of endoparasites in red-backed voles (Myodes gapperi) to fire in a boreal forest ecosystem. Because fire affects the environmental conditions and biodiversity of the forest ecosystem, the life cycle of parasites may also be affected because of the absence of intermediate hosts in the environment. We hypothesized that the prevalence of endoparasites would be influenced by the parasites' life cycle and habitat characteristics (forest vs. burned). We found that prevalence of endoparasites was different between forested and burned habitats (chi(2)=37.49, P<0.001). Cestodes, nematodes, and coccidia showed different responses to habitat alteration (chi(2)=37.43, P<0.001). There was a higher prevalence of cestodes in forested (53.5%) than burned habitats (35.0%). However, there was higher prevalence of coccidia in burned (55.0%) than forested (42.9%) habitats. Furthermore, although prevalence of cestode infection was lower in burned than forested habitat, individuals in both habitats had similar intensities of cestodes. Our study showed that habitat can significantly affect the parasite communities, depending on specific parasite life cycles. PMID:20090027

  16. The forest products industry in southeast Asia: An emphasis on Indonesia

    SciTech Connect

    Choong, E.T. . School of Forestry, Wildlife, and Fisheries); Atmawidjaja, R. . Faculty of Forestry); Achmadi, S.S. . Faculty of Mathematics and Natural Science)

    1993-05-01

    Wood production has increased rapidly in Southeast Asia in recent years. Harvesting intensity has also increased dramatically. To such an extent that the destruction of the tropical rainforest is of great concern to many people. This paper discusses the forest resources of three major wood-producing countries of Southeast Asia: Indonesia, Malaysia, and the Philippines, and the utilization of these resources in world markets. Because Indonesia is now the largest timber producer in the region, special emphasis is placed on the development of its forest products industry. Concern for the tropical forest and the effect of sustainable forestry development on the growth of the forest products industry, the economy, and the social environment are discussed.

  17. Temporal Trends in Stream N Concentrations and Responses to Disturbances in US Forested Basins

    NASA Astrophysics Data System (ADS)

    Argerich, A.; Johnson, S. L.; Sebestyen, S. D.; Rhoades, C.; Greathouse, E.; Jones, J.; Knoepp, J.; Adams, M. B.; Likens, G.; Campbell, J. L.; McDowell, W. H.; Ice, G. G.; Amatya, D. M.; Wohlgemuth, P. M.

    2011-12-01

    USFS Experimental Forests and Ranges have been collecting stream hydrologic and chemistry data in reference and disturbed forested basins across the country for several decades. These sites are located across a gradient of climatic conditions and are uniquely positioned to examine stream chemistry trends during the last decades and to study water quality responses to natural disturbances and forest harvest. To increase our understanding of stream chemistry trends at sites that are considered reference, sites that have not had anthropogenic impacts in the last 70 years other than atmospheric deposition, we synthesized stream N data collected over 12 to 43 years from 22 forested reference basins from seven USFS Experimental Forest Research sites . Results show high temporal and spatial variability in stream water N concentrations and trends. Some reference basins within a single Experimental Forest displayed temporal N concentration trends in opposite directions, suggesting that local factors (i.e., aspect of the basin, precipitation, vegetation, geology and soil type, and moisture) may be more relevant than regional factors. Additionally, we found trends in streamwater N concentrations changing direction over time. These findings highlight the importance of long-term stream water chemistry studies with continuous records encompassing wide range of climatic variability since controls of N exports from headwater streams may vary at both fine and long temporal and spatial scales. With a better understanding of trends in reference basins, we are beginning to examine stream chemistry responses to multiple types of disturbances including forest harvesting, insect outbreaks, fires, and hurricanes. We analyzed data from a total of 33 disturbance events on 8 Experimental Forests to quantify both the magnitude and duration of stream N responses. This analysis will increase our understanding of water chemistry responses to disturbance across biomes.

  18. Snowmelt as a driver of ecosystem response in water limited mountain forests of the Western U.S.

    NASA Astrophysics Data System (ADS)

    Molotch, N. P.; Trujillo, E.

    2015-12-01

    Recent large-scale changes in snow cover over Western North America associated with climate warming may have widespread impacts on water availability. These changes have potentially varied impacts on water availability as snowmelt influences, soil moisture, streamflow, and evapotranspiration. These changes may significantly alter runoff production and gross primary productivity in mountain forests. Analysis of remotely sensed and in situ soil moisture data indicate strong sensitivities of the timing of peak soil moisture to the timing of snowmelt. Observations of vegetation greenness indicate strong forest and understory growth dependencies associated with snow accumulation, snowmelt, and soil moisture with peak snow water equivalent explaining 40-50% of inter-annual greenness variability in the Rocky Mountains. Examples of these dependencies will be presented based on the 2012 drought in the Southwestern US whereby near record low snow accumulation and record high potential evapotranspiration have resulted in record low forest greening as evident in the 30+ year satellite record. Forest response to aridity in 2012 was exacerbated by forest disturbance with greenness anomalies 90% greater in magnitude in Bark Beetle and Spruce Budworm affected areas versus undisturbed areas and 182% greater in magnitude in areas impacted by fire. Greenness sensitivities to aridity showed seasonal dependencies with record high Normalized Difference Vegetation Index (NDVI) values in April (14% above average) and record low NDVI values in July (7% below average). Gross primary productivity estimates from the Moderate Resolution Imaging Spectroradiometer (MODIS) and from the Niwot Ridge, Colorado Ameriflux tower indicate record high April GPP (30% and 90% above average for MODIS and the tower, respectively) and record low July GPP (19% and 30% below average, respectively). These energy, water, ecosystem relationships indicate that the sensitivity of ecosystems to changes in climate is

  19. Greenhouse Gas and Carbon Profile of the U.S. Forest Products Industry Value Chain

    PubMed Central

    2010-01-01

    A greenhouse gas and carbon accounting profile was developed for the U.S. forest products industry value chain for 1990 and 2004−2005 by examining net atmospheric fluxes of CO2 and other greenhouse gases (GHGs) using a variety of methods and data sources. Major GHG emission sources include direct and indirect (from purchased electricity generation) emissions from manufacturing and methane emissions from landfilled products. Forest carbon stocks in forests supplying wood to the industry were found to be stable or increasing. Increases in the annual amounts of carbon removed from the atmosphere and stored in forest products offset about half of the total value chain emissions. Overall net transfers to the atmosphere totaled 91.8 and 103.5 TgCO2-eq. in 1990 and 2005, respectively, although the difference between these net transfers may not be statistically significant. Net transfers were higher in 2005 primarily because additions to carbon stored in forest products were less in 2005. Over this same period, energy-related manufacturing emissions decreased by almost 9% even though forest products output increased by approximately 15%. Several types of avoided emissions were considered separately and were collectively found to be notable relative to net emissions. PMID:20355695

  20. Interactions between atmospheric circulation, nutrient deposition, and tropical forest primary production (Invited)

    NASA Astrophysics Data System (ADS)

    Randerson, J. T.; Chen, Y.; Rogers, B. M.; Morton, D. C.; van der Werf, G.; Mahowald, N. M.

    2010-12-01

    Tropical forests influence regional and global climate by means of several pathways, including by modifying surface energy exchange and by forming clouds. High levels of precipitation, leaching, and soil weathering limit nutrient availability in these ecosystems. Phosphorus (P) is a key element limiting net primary production, and in some areas, including forests recovering from prior disturbance, nitrogen (N) also may limit some components of production. Here we quantified atmospheric P and N inputs to these forests from fires using satellite-derived estimates of emissions and atmospheric models. In Africa and South America, cross-biome transport of fire-emitted aerosols and reactive N gases from savannas and areas near the deforestation frontier increased deposition of P and N in interior forests. Equatorward atmospheric transport during the dry (fire) season in one hemisphere was linked with surface winds moving toward the inter-tropical convergence zone (ITCZ) in the other hemisphere. Deposition levels were higher in tropical forests in Africa than in South America because of large savanna areas with high levels of fire emissions in both southern and northern Africa. We conclude by describing a potential feedback loop by which equatorward transport of fire emissions, dust, and spores sustains the productivity of tropical forests. We specifically assessed evidence that savanna-to-forest atmospheric transport of nutrients increases forest productivity, height, and rates of evapotranspiration (ET). In parallel, we examined the degree to which increases in ET and surface roughness in tropical forests have the potential to strengthen several components of the Hadley circulation, including deep convection, equatorward return flow (near the surface), and the intensity of seasonal drought in the subtropics (thereby increasing fires). These interactions are important for understanding biogeochemical - climate interactions on millennial timescales and for quantifying how

  1. Nitrogen Oxide Trace Gas Efflux and Soil N Dynamics in Response to N Inputs in Temperate Forests of the Northeastern U.S.

    NASA Astrophysics Data System (ADS)

    Venterea, R. T.; Groffman, P. M.; Verchot, L.; Magill, A.; Aber, J.; Fernandez, I.; Adams, M. B.; Castro, M.; Lovett, G.

    2003-12-01

    Forests in the northeastern U.S. continue to receive elevated inputs of nitrogen (N) in the form of atmospheric deposition. N deposition rates in this region have remained essentially constant over the past decade. Persistent N inputs to temperate forests may have impacts on local water quality, regional air quality, and the capacity of forest productivity to increase in response to increasing atmospheric carbon dioxide. Responses that become evident at the ecosystem scale may be traceable to process-level alterations in N cycling within the forest soil. During 2000 - 2001, we measured soil N cycling rates and soil-to-atmosphere exchange of N oxide trace gases at five forest sites situated along a gradient in atmospheric N deposition from West Virginia to Maine. Four of the five sites were located within long-term N addition studies. The most consistent response was an elevation in soil nitric oxide (NO) emissions, which we measured using closed-chambers. We found evidence that differences in predominant forest vegetation and/or land-use history may have resulted in differential responses with respect to NO emissions and also enhanced rates of gross and net nitrification. The data also supported the idea that atmospheric deposition of N and acidity may both combine synergistically to promote elevated rates of NO emissions due to a sequence of soil biotic and abiotic reactions.

  2. Production of edible mushrooms in forests: trends in development of a mycosilviculture.

    PubMed

    Savoie, Jean-Michel; Largeteau, Michèle L

    2011-02-01

    Developing the production of ectomycorrhizal (ECM) mushrooms in forest has become a challenge. Only a few ECM species are currently cultivable. Controlled mycorrhization practices offer promising advance to produce currently uncultivable ECM mushrooms. The persistence of the production of edible species, either cultivated or wild, depends on both the tree and the ecological environment (fungal communities, climate, soil, tree development). Developing adapted forest management practices appears to be means to improve production of edible ECM mushrooms. This review summarises current knowledge on the development of a science-based mycosilviculture for the production of edible ECM mushrooms. PMID:21132290

  3. A meta‐analysis of functional group responses to forest recovery outside of the tropics

    PubMed Central

    Ezard, Thomas H. G.; Martin, Philip A.; Newton, Adrian C.; Doncaster, C. Patrick

    2015-01-01

    Abstract Both active and passive forest restoration schemes are used in degraded landscapes across the world to enhance biodiversity and ecosystem service provision. Restoration is increasingly also being implemented in biodiversity offset schemes as compensation for loss of natural habitat to anthropogenic development. This has raised concerns about the value of replacing old‐growth forest with plantations, motivating research on biodiversity recovery as forest stands age. Functional diversity is now advocated as a key metric for restoration success, yet it has received little analytical attention to date. We conducted a meta‐analysis of 90 studies that measured differences in species richness for functional groups of fungi, lichens, and beetles between old‐growth control and planted or secondary treatment forests in temperate, boreal, and Mediterranean regions. We identified functional‐group–specific relationships in the response of species richness to stand age after forest disturbance. Ectomycorrhizal fungi averaged 90 years for recovery to old‐growth values (between 45 years and unrecoverable at 95% prediction limits), and epiphytic lichens took 180 years to reach 90% of old‐growth values (between 140 years and never for recovery to old‐growth values at 95% prediction limits). Non‐saproxylic beetle richness, in contrast, decreased as stand age of broadleaved forests increased. The slow recovery by some functional groups essential to ecosystem functioning makes old‐growth forest an effectively irreplaceable biodiversity resource that should be exempt from biodiversity offsetting initiatives. PMID:26040756

  4. A meta-analysis of functional group responses to forest recovery outside of the tropics.

    PubMed

    Spake, Rebecca; Ezard, Thomas H G; Martin, Philip A; Newton, Adrian C; Doncaster, C Patrick

    2015-12-01

    Both active and passive forest restoration schemes are used in degraded landscapes across the world to enhance biodiversity and ecosystem service provision. Restoration is increasingly also being implemented in biodiversity offset schemes as compensation for loss of natural habitat to anthropogenic development. This has raised concerns about the value of replacing old-growth forest with plantations, motivating research on biodiversity recovery as forest stands age. Functional diversity is now advocated as a key metric for restoration success, yet it has received little analytical attention to date. We conducted a meta-analysis of 90 studies that measured differences in species richness for functional groups of fungi, lichens, and beetles between old-growth control and planted or secondary treatment forests in temperate, boreal, and Mediterranean regions. We identified functional-group-specific relationships in the response of species richness to stand age after forest disturbance. Ectomycorrhizal fungi averaged 90 years for recovery to old-growth values (between 45 years and unrecoverable at 95% prediction limits), and epiphytic lichens took 180 years to reach 90% of old-growth values (between 140 years and never for recovery to old-growth values at 95% prediction limits). Non-saproxylic beetle richness, in contrast, decreased as stand age of broadleaved forests increased. The slow recovery by some functional groups essential to ecosystem functioning makes old-growth forest an effectively irreplaceable biodiversity resource that should be exempt from biodiversity offsetting initiatives. PMID:26040756

  5. Determining forest productivity and carbon dynamics in southeastern Ohio from remotely-sensed data

    NASA Astrophysics Data System (ADS)

    Watts, Stephen Earl

    Recently, there has been a great deal of interest in using forests to sequester carbon emitted by burning of fossil fuels. However, accurate data on net primary productivity and biogeochemical cycling of regional forests with good spatial resolution are currently unavailable within Ohio. Basing this study on southeastern Ohio ecosystems, there were four major objectives. First, develop methodology to utilize the Forest Inventory and Analysis (FIA) and State Soil Geographic (STATSGO) data at a spatial resolution of 30 m. Second, determine how well data on forest productivity correlate with remotely-sensed and soil characteristics data at a spatial resolution of 30 m. Third, use the above correlations to predict forest productivity at a spatial resolution of 30 m from remotely-sensed and soils data. Fourth, calculate the predicted aboveground annual carbon storage in the forests of southeastern Ohio at a spatial resolution of 30 m from the forest productivity data. Land cover, slope, and aspect were used to select the FIA plots that had the best spatial accuracy. Interpolation techniques were used to smooth the boundaries between soil classification units. There was a significant correlation between remotely-sensed soil characteristics variables and annual basal area increment (adjusted R2 = 0.40, p < 0.001). Validation of this model also showed a significant correlation (R2 = 0.30, p < 0.001). Predicted annual basal area increment in forested areas ranged from 0 to 1.12 m2/ha with a mean of 0.14 m2/ha, resulting in an estimate of 103,381 M2 for the entire study area, which was 26% higher than when calculated from the FIA database. Although nonforested areas were not included in the data analyses, the mean annual predicted annual basal area increment (0.02 m2/ha) was significantly lower in non-forested areas than in forested areas. Predicted aboveground annual biomass increment in forested areas ranged from 0 to 6475 kg/ha with a mean of 1401 kg/ha, resulting in a

  6. Modeling the Ecohydrologic Response of the Forest-Grassland Ecotone in Western Canada to Changes in Annual Precipitation

    NASA Astrophysics Data System (ADS)

    Yetemen, O.; Ireson, A. M.; Barr, A.; Melton, J. R.; Black, T. A.

    2015-12-01

    The ecotone between the southern boreal forest and the grassland of western Canada is controlled by the water balance, and is therefore sensitive to climate change. Although ecohydrologic fluxes are being investigated at the Boreal Ecosystem Research and Monitoring Sites (BERMS) at the stand level, the ecohydrologic response of this ecotone to climate change is poorly understood. We use CTEM (the Canadian Terrestrial Ecosystem Model), coupled to CLASS (the Canadian Land Surface Scheme), to explore the structural and functional responses of the forest-grassland ecotone to climatic variability. The initial evaluations of CLASS-CTEM are being done using data from three mature forest sites (jack pine, aspen and black spruce) at BERMS and one grassland site. The model is forced with observed climate data between 1997 and 2010 by using each year, run repeatedly with a 400 year spin up, as one climatic scenario. Preliminary results show a sigmoidal response of annual gross primary production (GPP) to annual precipitation within each plant functional type, with limited GPP at low precipitation, higher but uniform GPP at high precipitation, and an intermediate precipitation range where GPP responds sensitively to increasing precipitation.

  7. Differential Responses of Neotropical Mountain Forests to Climate Change during the Last Millenium

    NASA Astrophysics Data System (ADS)

    Figueroa-Rangel, B. L.; Olvera Vargas, M.

    2013-05-01

    The long-term perspective in the conservation of mountain ecosystems using palaeoecological and paleoclimatological techniques are providing with crucial information for the understanding of the temporal range and variability of ecological pattern and processes. This perception is contributing with means to anticipate future conditions of these ecosystems, especially their response to climate change. Neotropical mountain forests, created by a particular geological and climatic history in the Americas, represent one of the most distinctive ecosystems in the tropics which are constantly subject to disturbances included climate change. Mexico due to its geographical location between the convergence of temperate and tropical elements, its diverse physiography and climatic heterogeneity, contains neotropical ecosystems with high biodiversity and endemicity whose structure and taxonomical composition have changed along centurial to millennial scales. Different neotropical forests expand along the mountain chains of Mexico with particular responses along spatial and temporal scales. Therefore in order to capture these scales at fine resolution, sedimentary sequences from forest hollows were retrieved from three forest at different altitudes within 10 km; Pine forest (PF), Transitional forest (TF) and Cloud forest (CF). Ordination techniques were used to relate changes in vegetation with the environment every ~60 years. The three forests experience the effect of the dry stage ~AD 800-1200 related to the Medieval Warm Period reported for several regions of the world. CF contracted, PF expanded while the TF evolved from CF to a community dominated by dry-resistant epiphytes. Dry periods in PF and TF overlapped with the increase in fire occurrences while a dissimilar pattern took place in CF. Maize, Asteraceae and Poaceae were higher during dry intervals while epiphytes decreased. A humid period ~1200-1450 AD was associated with an expansion and a high taxa turnover in CF

  8. Complex response of the forest nitrogen cycle to climate change.

    PubMed

    Bernal, Susana; Hedin, Lars O; Likens, Gene E; Gerber, Stefan; Buso, Don C

    2012-02-28

    Climate exerts a powerful influence on biological processes, but the effects of climate change on ecosystem nutrient flux and cycling are poorly resolved. Although rare, long-term records offer a unique opportunity to disentangle effects of climate from other anthropogenic influences. Here, we examine the longest and most complete record of watershed nutrient and climate dynamics available worldwide, which was collected at the Hubbard Brook Experimental Forest in the northeastern United States. We used empirical analyses and model calculations to distinguish between effects of climate change and past perturbations on the forest nitrogen (N) cycle. We find that climate alone cannot explain the occurrence of a dramatic >90% drop in watershed nitrate export over the past 46 y, despite longer growing seasons and higher soil temperatures. The strongest climate influence was an increase in soil temperature accompanied by a shift in paths of soil water flow within the watershed, but this effect explained, at best, only ∼40% of the nitrate decline. In contrast, at least 50-60% of the observed change in the N export could be explained by the long-lasting effect of forest cutting in the early 1900s on the N cycle of the soil and vegetation pools. Our analysis shows that historic events can obscure the influence of modern day stresses on the N cycle, even when analyses have the advantage of being informed by 0.5-century-long datasets. These findings raise fundamental questions about interpretations of long-term trends as a baseline for understanding how climate change influences complex ecosystems. PMID:22331889

  9. The linkages between photosynthesis, productivity, growth and biomass in lowland Amazonian forests.

    PubMed

    Malhi, Yadvinder; Doughty, Christopher E; Goldsmith, Gregory R; Metcalfe, Daniel B; Girardin, Cécile A J; Marthews, Toby R; Del Aguila-Pasquel, Jhon; Aragão, Luiz E O C; Araujo-Murakami, Alejandro; Brando, Paulo; da Costa, Antonio C L; Silva-Espejo, Javier E; Farfán Amézquita, Filio; Galbraith, David R; Quesada, Carlos A; Rocha, Wanderley; Salinas-Revilla, Norma; Silvério, Divino; Meir, Patrick; Phillips, Oliver L

    2015-06-01

    Understanding the relationship between photosynthesis, net primary productivity and growth in forest ecosystems is key to understanding how these ecosystems will respond to global anthropogenic change, yet the linkages among these components are rarely explored in detail. We provide the first comprehensive description of the productivity, respiration and carbon allocation of contrasting lowland Amazonian forests spanning gradients in seasonal water deficit and soil fertility. Using the largest data set assembled to date, ten sites in three countries all studied with a standardized methodology, we find that (i) gross primary productivity (GPP) has a simple relationship with seasonal water deficit, but that (ii) site-to-site variations in GPP have little power in explaining site-to-site spatial variations in net primary productivity (NPP) or growth because of concomitant changes in carbon use efficiency (CUE), and conversely, the woody growth rate of a tropical forest is a very poor proxy for its productivity. Moreover, (iii) spatial patterns of biomass are much more driven by patterns of residence times (i.e. tree mortality rates) than by spatial variation in productivity or tree growth. Current theory and models of tropical forest carbon cycling under projected scenarios of global atmospheric change can benefit from advancing beyond a focus on GPP. By improving our understanding of poorly understood processes such as CUE, NPP allocation and biomass turnover times, we can provide more complete and mechanistic approaches to linking climate and tropical forest carbon cycling. PMID:25640987

  10. Regulatory and information support for evaluation of biological productivity of Ukrainian forests and climate change

    NASA Astrophysics Data System (ADS)

    Lakyda, Petro; Vasylyshyn, Roman; Lakyda, Ivan

    2013-04-01

    Stabilization and preservation of the planet's climate system today is regarded as one of the most important global political-economic, environmental and social problems of mankind. Rising concentration of carbon dioxide in the planet's atmosphere due to anthropogenic impact is the main reason leading to global climate change. Due to the above mentioned, social demands on forests are changing their biosphere role and function of natural sink of greenhouse gases becomes top priority. It is known that one of the most essential components of biological productivity of forests is their live biomass. Absorption, long-term sequestration of carbon and generation of oxygen are secured by its components. System research of its parametric structure and development of regulatory and reference information for assessment of aboveground live biomass components of trees and stands of the main forest-forming tree species in Ukraine began over twenty-five years ago at the department of forest mensuration and forest inventory of National University of Life and Environmental Sciences of Ukraine, involving staff from other research institutions. Today, regulatory and reference materials for evaluation of parametric structure of live biomass are developed for trees of the following major forest-forming tree species of Ukraine: Scots pine of natural and artificial origin, Crimean pine, Norway spruce, silver fir, pedunculate oak, European beech, hornbeam, ash, common birch, aspen and black alder (P.I. Lakyda et al., 2011). An ongoing process on development of similar regulatory and reference materials for forest stands of the abovementioned forest-forming tree species of Ukraine is secured by scientists of departments of forest management, and forest mensuration and forest inventory. The total experimental research base is 609 temporary sample plots, where 4880 model trees were processed, including 3195 model trees with estimates of live biomass components. Laboratory studies conducted

  11. Model-experiment synthesis at two FACE sites in the southeastern US. Forest ecosystem responses to elevated CO[2]. (Invited)

    NASA Astrophysics Data System (ADS)

    Walker, A. P.; Zaehle, S.; De Kauwe, M. G.; Medlyn, B. E.; Dietze, M.; Hickler, T.; Iversen, C. M.; Jain, A. K.; Luo, Y.; McCarthy, H. R.; Parton, W. J.; Prentice, C.; Thornton, P. E.; Wang, S.; Wang, Y.; Warlind, D.; Warren, J.; Weng, E.; Hanson, P. J.; Oren, R.; Norby, R. J.

    2013-12-01

    Ecosystem observations from two long-term Free-Air CO[2] Enrichment (FACE) experiments (Duke forest and Oak Ridge forest) were used to evaluate the assumptions of 11 terrestrial ecosystem models and the consequences of those assumptions for the responses of ecosystem water, carbon (C) and nitrogen (N) fluxes to elevated CO[2] (eCO[2]). Nitrogen dynamics were the main constraint on simulated productivity responses to eCO[2]. At Oak Ridge some models reproduced the declining response of C and N fluxes, while at Duke none of the models were able to maintain the observed sustained responses. C and N cycles are coupled through a number of complex interactions, which causes uncertainty in model simulations in multiple ways. Nonetheless, the major difference between models and experiments was a larger than observed increase in N-use efficiency and lower than observed response of N uptake. The results indicate that at Duke there were mechanisms by which trees accessed additional N in response to eCO[2] that were not represented in the ecosystem models, and which did not operate with the same efficiency at Oak Ridge. Sequestration of the additional productivity under eCO[2] into forest biomass depended largely on C allocation. Allocation assumptions were classified into three main categories--fixed partitioning coefficients, functional relationships and a partial (leaf allocation only) optimisation. The assumption which best constrained model results was a functional relationship between leaf area and sapwood area (pipe-model) and increased root allocation when nitrogen or water were limiting. Both, productivity and allocation responses to eCO[2] determined the ecosystem-level response of LAI, which together with the response of stomatal conductance (and hence water-use efficiency; WUE) determined the ecosystem response of transpiration. Differences in the WUE response across models were related to the representation of the relationship of stomatal conductance to CO[2] and

  12. Intra-annual response of tree growth to climate in temperate forests: larger implications of fine-scale responses

    NASA Astrophysics Data System (ADS)

    McMahon, S.; Parker, G. G.

    2013-12-01

    Tree growth is a key component in the movement of carbon through terrestrial ecosystems. Although correlating annual growth rates to temperature an precipitation averages is the most common approach to extrapolating climate sensitivities, individual trees respond to weather at a much finer temporal scale. This response, further, is sensitive to many environmental factors and that sensitivity can depend on species, individual location in the species range, or size of the individual among other factors. Using weekly and bi-weekly measurements of dendrometer bands on 100 trees in three sites in the eastern US (Massachusetts, Virginia, and Maryland) over four years, we fit functional forms to intra-annual growth and compared patterns in productivity response to daily temperature and water balance information. We also determined phenological patterns in growth initiation, cessation, and maximum rate. We found that across size classes and species, trees respond to high temperatures and minor droughts by pausing in diameter increase. Although water retention may contribute some to this pattern, large differences in end-of-year biomass gain demonstrate a clear relationship between these pauses and overall annual carbon gain. Species did show some distinct patterns in this sensitivity and the overall phenology of growth. Further, the growing season as defined by when the majority of biomass increase actually occurred was much smaller than the leaf-out season indicating that droughts and heat-waves in a key subset of the green season can have a disproportionate effect on tree carbon uptake and forest carbon balance.

  13. VARIABILITY IN NET PRIMARY PRODUCTION AND CARBON STORAGE IN BIOMASS ACROSS OREGON FORESTS - AN ASSESSMENT INTEGRATING DATA FROM FOREST INVENTORIES, INTENSIVE SITES, AND REMOTE SENSING. (R828309)

    EPA Science Inventory

    We used a combination of data from USDA Forest Service inventories, intensive
    chronosequences, extensive sites, and satellite remote sensing, to estimate biomass
    and net primary production (NPP) for the forested region of western Oregon. The
    study area was divided int...

  14. Temperature response of the submicron organic aerosol from temperate forests

    NASA Astrophysics Data System (ADS)

    Leaitch, W. Richard; Macdonald, Anne Marie; Brickell, Peter C.; Liggio, John; Sjostedt, Steve J.; Vlasenko, Alexander; Bottenheim, Jan W.; Huang, Lin; Li, Shao-Meng; Liu, Peter S. K.; Toom-Sauntry, Desiree; Hayden, Katherine A.; Sharma, Sangeeta; Shantz, Nicole C.; Wiebe, H. Allan; Zhang, Wendy; Abbatt, Jonathan P. D.; Slowik, Jay G.; Chang, Rachel Y.-W.; Russell, Lynn M.; Schwartz, Rachel E.; Takahama, Satoshi; Jayne, John T.; Ng, Nga Lee

    2011-12-01

    Observations from four periods (three late springs and one early summer) at temperate forest sites in western and eastern Canada offer the first estimation of how the concentrations of submicron forest organic aerosol mass (SFOM) from the oxidation of biogenic volatile organic compounds (BVOC) vary over the ambient temperature range of 7 °C to 34 °C. For the measurement conditions of clear skies, low oxides of nitrogen and within approximately one day of emissions, 50 estimates of SFOM concentrations show the concentrations increase exponentially with temperature. The model that is commonly used to define terpene emissions as a function of temperature is able to constrain the range of the SFOM values across the temperature range. The agreement of the observations and model is improved through the application of an increased yield of SFOM as the organic mass concentration increases with temperature that is based on results from chamber studies. The large range of SFOM concentrations at higher temperatures leaves open a number of questions, including the relative contributions of changing yield and of isoprene, that may be addressed by more ambient observations at higher temperatures.

  15. Forest production predicted from satellite image analysis for the Southeast Asia region

    PubMed Central

    2013-01-01

    Background The objective of this study was to demonstrate a new, cost-effective method to define the sustainable amounts of harvested wood products in Southeast Asian countries case studies, while avoiding degradation (net loss) of total wood carbon stocks. Satellite remote sensing from the MODIS sensor was used in the CASA (Carnegie Ames Stanford Approach) carbon cycle model to map forest production for the Southeast Asia region from 2000 to 2010. These CASA model results have been designed to be spatially detailed enough to support carbon cycle assessments in different wooded land cover classes, e.g., open woodlands, wetlands, and forest areas. Results The country with the highest average forest net primary production (NPP greater than 950 g C m-2 yr-1) over the period was the Philippines, followed by Malaysia and Indonesia. Myanmar and Vietnam had the lowest average forest NPP among the region’s countries at less than 815 g C m-2 yr-1. Case studies from throughout the Southeast Asia region for the maximum harvested wood products amount that could be sustainably extracted per year were generated using the CASA model NPP predictions. Conclusions The method of using CASA model’s estimated annual change in forest carbon on a yearly basis can conservatively define the upper limit for the amount of harvested wood products that can be removed and still avoid degradation (net loss) of the total wood carbon stock over that same time period. PMID:24016254

  16. Microbial Responses to Forest Management in the Western Gulf Coastal Plain, USA

    NASA Astrophysics Data System (ADS)

    Foote, J. A.; Boutton, T. W.; Scott, D. A.

    2013-12-01

    Microbial communities are integral components of the biogeochemistry, fertility, and structure of forest soils, and land management practices that alter the microbial environment may influence the long-term sustainability and productivity of forestlands. In 1989 the Long-term Soil Productivity (LTSP) program was initiated to address the National Forest Management Act's concerns over possible losses in soil productivity due to soil disturbance from forest management on National Forest lands. The LTSP program is a network of 62 sites across the USA and Canada that employs the same 3X3 replicated (X3) factorial experimental design consisting of three harvest intensities (bole only, whole tree, whole tree + forest floor removal) with three soil compaction intensities (none, intermediate, severe) and plots that were split for herbicide when the experiment was initiated. Our purpose was to determine the impact of forest harvest intensity, soil compaction, and their interaction on soil microbial biomass C and N (SMB-C, -N) and soil total nitrogen (TN) and soil organic carbon (SOC) storage in a Pinus taeda L. forest 15-years post-treatment at the Davy Crockett National Forest LTSP site in eastern Texas, USA. We quantified SMB-C and -N using the chloroform fumigation extraction method, and TN and SOC by dry combustion. Soils are loamy sand and were sampled 5X during 2011-2012. In each split-plot, five samples were obtained between two living P. taeda stems to a depth of 10-cm and pooled in the field. Because soil compaction, harvest by soil compaction interaction, and herbicide had no effect on the measured soil properties, results are based on repeated measures ANOVA using harvest and time. Both SMB-C and -N were impacted by harvest and varied with time, and SMB-C had a harvest by time interaction. Generally, both microbial indices decreased in the order: bole only >whole tree > whole tree + forest floor. Soil TN and SOC were both higher in the bole only treatment compared

  17. The upper mountain forest and tree response to climate change in south Siberian Mountains

    NASA Astrophysics Data System (ADS)

    Kharuk, V.; Ranson, J.

    2010-12-01

    to the areas of 10-40 m higher in elevation. Regeneration has propagated into the alpine tundra at the rate of ~1.0 - 2.0 m/yr. Siberian pine and larch regeneration surpassed their upper historical limit by 10-80 m in elevation. We will show that spatial patterns of upper mountain forests as well as forest response to warming strongly depends on topographic features . With elevation increase (and thus a harsher environment) forests shifted to steep wind-protected slopes. A considerable increase of the stand area and increased elevation of the upper forest line was observed coincident with the climate warming that was observed. A warming climate provides competitive advantages to Siberian pine in areas with sufficient precipitation. Larch is more tolerant of harsh climates and exhibits an arboreal growth form where Siberian pine is in krummholz form. Warming winter temperatures have been sufficient for increased survival of regeneration. Larch also has an advantage at the upper tree limit and in the areas with low precipitation. Climate-induced forest response significantly modified the spatial patterns of high elevation forests in southern Siberia during the last four decades, as well as tree morphology.

  18. Accounting for forest carbon pool dynamics in product carbon footprints: Challenges and opportunities

    SciTech Connect

    Newell, Joshua P.; Vos, Robert O.

    2012-11-15

    Modification and loss of forests due to natural and anthropogenic disturbance contribute an estimated 20% of annual greenhouse gas (GHG) emissions worldwide. Although forest carbon pool modeling rarely suggests a 'carbon neutral' flux profile, the life cycle assessment community and associated product carbon footprint protocols have struggled to account for the GHG emissions associated with forestry, specifically, and land use generally. Principally, this is due to underdeveloped linkages between life cycle inventory (LCI) modeling for wood and forest carbon modeling for a full range of forest types and harvest practices, as well as a lack of transparency in globalized forest supply chains. In this paper, through a comparative study of U.S. and Chinese coated freesheet paper, we develop the initial foundations for a methodology that rescales IPCC methods from the national to the product level, with reference to the approaches in three international product carbon footprint protocols. Due to differences in geographic origin of the wood fiber, the results for two scenarios are highly divergent. This suggests that both wood LCI models and the protocols need further development to capture the range of spatial and temporal dimensions for supply chains (and the associated land use change and modification) for specific product systems. The paper concludes by outlining opportunities to measure and reduce uncertainty in accounting for net emissions of biogenic carbon from forestland, where timber is harvested for consumer products. - Highlights: Black-Right-Pointing-Pointer Typical life cycle assessment practice for consumer products often excludes significant land use change emissions when estimating carbon footprints. Black-Right-Pointing-Pointer The article provides a methodology to rescale IPCC guidelines for product-level carbon footprints. Black-Right-Pointing-Pointer Life cycle inventories and product carbon footprint protocols need more comprehensive land use

  19. Forest soil respiration reflects plant productivity across a temperature gradient in the Alps.

    PubMed

    Caprez, Riccarda; Niklaus, Pascal A; Körner, Christian

    2012-12-01

    Soil respiration (R (s)) plays a key role in any consideration of ecosystem carbon (C) balance. Based on the well-known temperature response of respiration in plant tissue and microbes, R (s) is often assumed to increase in a warmer climate. Yet, we assume that substrate availability (labile C input) is the dominant influence on R (s) rather than temperature. We present an analysis of NPP components and concurrent R (s) in temperate deciduous forests across an elevational gradient in Switzerland corresponding to a 6 K difference in mean annual temperature and a considerable difference in the length of the growing season (174 vs. 262 days). The sum of the short-lived NPP fractions ("canopy leaf litter," "understory litter," and "fine root litter") did not differ across this thermal gradient (+6 % from cold to warm sites, n.s.), irrespective of the fact that estimated annual forest wood production was more than twice as high at low compared to high elevations (largely explained by the length of the growing season). Cumulative annual R (s) did not differ significantly between elevations (836 ± 5 g C m(-2) a(-1) and 933 ± 40 g C m(-2) a(-1) at cold and warm sites, +12 %). Annual soil CO(2) release thus largely reflected the input of labile C and not temperature, despite the fact that R (s) showed the well-known short-term temperature response within each site. However, at any given temperature, R (s) was lower at the warm sites (downregulation). These results caution against assuming strong positive effects of climatic warming on R (s), but support a close substrate relatedness of R (s). PMID:22684867

  20. Generation of cytotoxic and humoral immune responses by nonreplicative recombinant Semliki Forest virus.

    PubMed Central

    Zhou, X; Berglund, P; Zhao, H; Liljeström, P; Jondal, M

    1995-01-01

    The Semliki Forest virus (SFV) expression system can be used to package recombinant RNA into infectious suicide particles. Such RNA encodes only the SFV replicase and the heterologous protein but no structural proteins of SFV, and it is thus deficient in productive replication. We demonstrate here that infection of C57BL/6 (H-2b) and BALB/c (H-2d) mice with recombinant SFV expressing the nucleoprotein (NP) of influenza virus (SFV-NP) resulted in efficient priming of influenza virus-specific CD8+ cytotoxic T-cell (CTL) responses. The generated CTLs lysed both homologous (A/PR/8/34) and heterologous (A/HK/68) influenza virus-infected, or peptide-coated, target cells to a similar degree as CTLs induced by wild-type influenza virus in a major histocompatibility complex class I-restricted fashion. As few as 100 infectious units of virus induced a strong CTL response. Induction of CTL by SFV-NP could also be achieved in CD4 gene-targeted mice, demonstrating the independence of the primary CTL response of CD4+ helper T cells. One immunization generated a CTL response that peaked after 1 week, and an additional booster injection generated a CTL memory, which was still detectable after 40 days. SFV-NP immunizations also generated high-titered IgG humoral responses that remained significant after several months. These results demonstrate that the recombinant SFV suicide system is highly efficient in antigen presentation and suggest that it may have a potential as a recombinant vaccine. Images Fig. 1 PMID:7708765

  1. Effect of oil and oil products on lipase activity in gray forest soil

    NASA Astrophysics Data System (ADS)

    Kireeva, N. A.; Tarasenko, E. M.; Shamaeva, A. A.; Novoselova, E. I.

    2006-08-01

    The effect of different rates of oil and oil products on the lipase activity in gray forest soil was studied under field and laboratory conditions. It was found that hydrocarbons activate the lipolytic activity of the soil. Along with the activation of lipolysis, an increase in the number of hydrocarbon-oxidizing microorganisms and a decrease in the content of oil products were observed.

  2. [Carbon density and production in valley spruce-fir forest in Xiaoxing'an Mountains, China].

    PubMed

    Cai, Hui-Ying; Di, Xue-Ying; Jin, Guang-Ze

    2014-10-01

    The carbon density and production were measured using both forest inventory and allometry approaches in the declining valley spruce-fir forest in Xiaoxing' an Mountains. Results showed that the total carbon density of the forest was 268. 14 t C · hm(-2) in 2011, and carbon densities of the vegetation, detritus and soil were 74.25, 16.86 and 177.03 t C · hm(-2), respectively. From 2006 to 2011, tree layer carbon density decreased from 80.86 t C · hm(-2) to 71.73 t C · hm(-2). The average decrease proportions per year of carbon density were 0.5%, 1.2%, 2.7% and 3.7% for Abies nephrolepis, Betula platyphylla, Picea spp., and Larix gmelinii, respectively. However, carbon densities were increased by 2.9%, 3.9% and 7.2% per year for Alnus sibirica, Pinus koraiensis and Acer ukurunduense, respectively. Net primary production (NPP) of the forest was 4.69 t C · hm(-2) · a(-1). The ratio of belowground NPP to aboveground NPP was 0.56. Litterfall accounted for the largest proportion of the NPP of forest with a value of 34.5%. As the two most important carbon output approaches of forest ecosystems, the fluxes of heterotrophic respiration and coarse woody debris decomposition were 293.67 and 119.29 g C · m(-2) · a(-1), respectively. Net ecosystem production (NEP) of the forest was 55.90 g C · m(-2) a(-1). The results indicated that the valley spruce-fir forest in the declining state still had a certain carbon sink capacity. PMID:25796884

  3. ALGAL RESPONSE TO NUTRIENT ENRICHMENT IN FORESTED OLIGOTROPHIC STREAM(1).

    PubMed

    Veraart, Annelies J; Romaní, Anna M; Tornés, Elisabet; Sabater, Sergi

    2008-06-01

    Nutrient input in streams alters the density and species composition of attached algal communities in open systems. However, in forested streams, the light reaching the streambed (rather than the local nutrient levels) may limit the growth of these communities. A nutrient-enrichment experiment in a forested oligotrophic stream was performed to test the hypothesis that nutrient addition has only minor effects on the community composition of attached algae and cyanobacteria under light limitation. Moderate nutrient addition consisted of increasing basal phosphorus (P) concentrations 3-fold and basal nitrogen (N) concentrations 2-fold. Two upstream control reaches were compared to a downstream reach before and after nutrient addition. Nutrients were added continuously to the downstream reach for 1 year. Algal biofilms growing on ceramic tiles were sampled and identified for more than a year before nutrient addition to 12 months after. Diatoms were the most abundant taxonomic group in the three stream reaches. Nutrient enrichment caused significant variations in the composition of the diatom community. While some taxa showed significant decreases (e.g., Achnanthes minutissima, Gomphonema angustum), increases for other taxa (such as Rhoicosphenia abbreviata and Amphora ovalis) were detected in the enriched reach (for taxonomic authors, see Table 2). Epiphytic and adnate taxa of large size were enhanced, particularly during periods of favorable growth conditions (spring). Nutrients also caused a change in the algal chl a, which increased from 0.5-5.8 to 2.1-10.7 μg chl · cm(-2) . Our results indicate that in oligotrophic forested streams, long-term nutrient addition has significant effects on the algal biomass and community composition, which are detectable despite the low light availability caused by the tree canopy. Low light availability moderates but does not detain the long-term tendency toward a nutrient-tolerant community. Furthermore, the effects

  4. A meta-analysis of soil microbial biomass responses to forest disturbances

    PubMed Central

    Holden, Sandra R.; Treseder, Kathleen K.

    2013-01-01

    Climate warming is likely to increase the frequency and severity of forest disturbances, with uncertain consequences for soil microbial communities and their contribution to ecosystem C dynamics. To address this uncertainty, we conducted a meta-analysis of 139 published soil microbial responses to forest disturbances. These disturbances included abiotic (fire, harvesting, storm) and biotic (insect, pathogen) disturbances. We hypothesized that soil microbial biomass would decline following forest disturbances, but that abiotic disturbances would elicit greater reductions in microbial biomass than biotic disturbances. In support of this hypothesis, across all published studies, disturbances reduced soil microbial biomass by an average of 29.4%. However, microbial responses differed between abiotic and biotic disturbances. Microbial responses were significantly negative following fires, harvest, and storms (48.7, 19.1, and 41.7% reductions in microbial biomass, respectively). In contrast, changes in soil microbial biomass following insect infestation and pathogen-induced tree mortality were non-significant, although biotic disturbances were poorly represented in the literature. When measured separately, fungal and bacterial responses to disturbances mirrored the response of the microbial community as a whole. Changes in microbial abundance following disturbance were significantly positively correlated with changes in microbial respiration. We propose that the differential effect of abiotic and biotic disturbances on microbial biomass may be attributable to differences in soil disruption and organic C removal from forests among disturbance types. Altogether, these results suggest that abiotic forest disturbances may significantly decrease soil microbial abundance, with corresponding consequences for microbial respiration. Further studies are needed on the effect of biotic disturbances on forest soil microbial communities and soil C dynamics. PMID:23801985

  5. Forests or fields? A response to the theory that tropical forest conservation poses a threat to the poor.

    PubMed

    Fearnside, P M

    1993-04-01

    A rebuttal is provided of David Wood's proposal to open up tropical forests to agricultural uses. Concern is raised that his proposal exaggerates the ability of forests to regenerate after agricultural uses, sacrifices tropical forests in the name of alleviating poverty and in support of large land owners, and prevents valuable potential resource use by local populations. There is misunderstanding by Wood of conservationists' postures and the cause of current deforestation. In Brazil, deforestation has occurred primarily for low productivity cattle pasture (62% of all private land in the Amazon region in ranches over 1000 hectares-ha). Only 11% of private Amazonian land was in farms of less than 100 ha; only 30% of this size farm area was involved in 1991 in deforestation, while 70% of deforestation took place on ranches over 100 ha. Mass migrations of Brazil's population from the northeast to the Transamazon Highway and from Parana to Rondonia were impelled by increasing concentration of land tenure in migrant areas, and not by population growth. The rate of deforestation has slowed due to the economic recession. A World Bank study indicates that redistributing unproductive large landholdings in northeastern Brazil would increase agricultural output by 80%. The agricultural productivity of tropic areas is not as assured; Wood's support is based on preliminary findings, which are being revised with more cautionary thinking. Wood also understates the maintenance of soil fertility with fertilizers. The issue of scale also affects the use of agroforestry and perennial crop plantations such as rubber and cacao, which can only absorb the production of small areas, due to marketing constraints and physical resource limitations. Conservationists have not effectively redirected World Bank efforts to protect environments and help the impoverished, as suggested by Wood. Forest recovery has been very slow in large cattle pastures, and would take thousands of years if the land

  6. Policy responses to the productivity slowdown

    SciTech Connect

    Nordhaus, W.D.

    1980-06-01

    A slowdown in the growth rate of labor productivity in the US (productivity slowdown) is discussed in this review. The generally accepted reasons for the slowdown are presented. A theory of depletion vs obstacle in describing productivity slowdown is presented. Policy responses to problems of productivity slowdown are described. Views presented include: (a) a change of taste toward no growth philosophies; (b) undersaving and underinvesting; (c) self-inflicted wounds i.e. payroll taxes, minimum wage, trade restrictions, etc.; and (d) depletion in extractive industries, investment opportunities, and inventions. Specific policy responses are discussed including: anti-inflation policy; demand management policies; investment; energy; and regulation.

  7. Wildfires effect on water erosion response of different mediterranean forest soils

    NASA Astrophysics Data System (ADS)

    Andreu, V.; Forteza, J.; Rubio, J. L.

    2009-04-01

    Some of the morphological characteristics of the Mediterranean landscapes are partly due to the incidence of forest fires. Different intensities and different environmental conditions give place to different forms of water erosion responses and ways of ecosystems recovery. In this work, the effect of fire on the response to erosion processes of different type of soils under different environmental conditions has been studied. Immediately after a wildfire that affected 9478 ha of the Sierra Calderona (Valencia, SPAIN), six monitoring stations to study the evolution of water erosion processes were placed. The stations cover different fire intensities and environmental situations. Topographical, pedological and vegetation characteristics of each station were studied. The effect of erosive rain events on runoff and sediment production, during a five years period was evaluated. Erosive patterns in the studied zones were similar, but with slight variations depending on the rainfall distribution on the whole area and the different topographical conditions. The data show that, in general, for all the stations the most important soil losses were produced in the first four months after the fire, and then these losses decrease progressively with time. Although the data show high heterogeneity, it has been observed that together with the intrinsic characteristics of fire and rain events, soil profile properties can also be determinant factors in the incidence of water erosion and in the recovery of the vegetation cover under similar environmental conditions. Keywords: Wildfires, Mediterranean soils, water erosion, soil loss, runoff generation, rain aggressiveness.

  8. Revised paradigms of forest production over stand development: Why does carbon storage increase as trees die in aging mixed temperate forests?

    NASA Astrophysics Data System (ADS)

    Gough, C. M.; Curtis, P.; Hardiman, B. S.; Scheuermann, C. M.

    2013-12-01

    The broad emergence of century-old forests in the US upper Midwest and Northeast has large potential implications for carbon (C) storage, as the long-assumed future decline of production in aging stands is expected to reduce continental C sink strength. As mixed temperate forests in the region broadly transition from early to middle stages of succession, short-lived canopy trees are dying and giving way to more structurally complex forests. At the same time, disturbances in the region are shifting from severe events to more moderate disturbances resulting in only partial canopy defoliation. We review new evidence that temperate deciduous forests, against prior expectations, are likely to maintain their capacity to store C over the next several decades even as diffuse mortality of canopy trees increases with advancing age. Forest production data from long-term observational studies and experimental chronosequences in the region do not support a decline in C storage during middle succession. Instead, sustained forest C storage in intermediate-aged forests corresponds with the accrual of structural complexity over time from small-scale, non-stand replacing disturbances such as age-related mortality. Increasing complexity with age gives rise to more efficient use of growth-limiting light and nutrient resources, which may offset, in part or whole, the lost contribution of senescent canopy trees to forest production. These findings indicate that older, structurally complex forests that emerge following diffuse mortality may store C at rates comparable to their younger counterparts. We conclude that regional land-use decisions permitting age-related senescence in maturing forests or, alternatively, management outcomes emulating the structural features of older forests will support goals to maintain the region's C sink strength.

  9. [Responses of forest soil carbon pool and carbon cycle to the changes of carbon input].

    PubMed

    Wang, Qing-kui

    2011-04-01

    Litters and plant roots are the main sources of forest soil organic carbon (C). This paper summarized the effects of the changes in C input on the forest soil C pool and C cycle, and analyzed the effects of these changes on the total soil C, microbial biomass C, dissoluble organic C, and soil respiration. Different forests in different regions had inconsistent responses to C input change, and the effects of litter removal or addition and of root exclusion or not differed with tree species and regions. Current researches mainly focused on soil respiration and C pool fractions, and scarce were about the effects of C input change on the changes of soil carbon structure and stability as well as the response mechanisms of soil organisms especially soil fauna, which should be strengthened in the future. PMID:21774335

  10. Regulating riparian forests for aquatic productivity in the Pacific Northwest, USA: addressing a paradox.

    PubMed

    Newton, Michael; Ice, George

    2016-01-01

    Forested riparian buffers isolate streams from the influence of harvesting operations that can lead to water temperature increases. Only forest cover between the sun and stream limits stream warming, but that cover also reduces in-stream photosynthesis, aquatic insect production, and fish productivity. Water temperature increases that occur as streams flow through canopy openings decrease rapidly downstream, in as little as 150 m. Limiting management options in riparian forests restricts maintenance and optimization of various buffer contributions to beneficial uses, including forest products, fish, and their food supply. Some riparian disturbance, especially along cold streams, appears to benefit fish productivity. Options for enhancing environmental investments in buffers should include flexibility in application of water quality standards to address the general biological needs of fish and temporary nature of clearing induced warming. Local prescriptions for optimizing riparian buffers and practices that address long-term habitat needs deserve attention. Options and incentives are needed to entice landowners to actively manage for desirable riparian forest conditions. PMID:26611633

  11. Local and Regional Economic Benefits from Forest Products Production Activities at the Savannah River Site: 1955-Present

    SciTech Connect

    Teeter, L.; Blake, J.I.

    2002-01-01

    SRS was established in 1951 as a nuclear materials production facility; however, decline in the defense mission budget at SRS has created a major economic impact on the community in the Central Savannah River Area. SRS has been offsetting these effects by producing revenue (80 million dollars to date) from the sale of forest products since 1955 primarily trees, but also pine straw. Revenue has been re-invested into the infrastructure development, restoration and management of natural resources. Total asset value of the forest-land has increased from 21 million to over 500 million dollars in the same period.

  12. Linking Stream Nitrate to Forest Response and Recovery after Severe Bark Beetle Infestation (Invited)

    NASA Astrophysics Data System (ADS)

    Rhoades, C.; Hubbard, R. M.; Elder, K.

    2013-12-01

    Biogeochemical responses and ecosystem recovery from bark beetle outbreaks are influenced by pre-disturbance forest structure and composition and catchment conditions. Over the past decade, the mountain pine bark beetle (Dendroctonus ponderosae) has killed mature lodgepole pine (Pinus contorta) trees at the Fraser Experimental Forest and throughout the Colorado Rockies. Here we compare stream nitrogen (N) concentrations during the outbreak with data from the previous two decades in four research catchments with distinct forest management history, stand age structure and watershed characteristics. In two old growth forest catchments, stream nitrate concentrations were significantly higher during the infestation in the snowmelt and base flow seasons. The beetle infestation elevated nitrate export 43 and 74% in these two catchments though the amounts of N released in streamwater (0.04 and 0.15 kg N ha-1) were < 2% of annual atmospheric inputs. In contrast, nitrate concentrations were unaffected by beetle infestation in two catchments comprised of a mixture of second-growth (30-60 year old) and old-growth (250-350 year old) forest stands where the density of residual live trees was higher on average. Mortality of overstory trees from bark beetles has stimulated the growth of understory and overstory trees with likely consequences for nutrient demand and retention in recovering forests.

  13. The Nitrogen Budget of a Northern Hardwood Forest: Sources and net Primary Productivity Requirements

    NASA Astrophysics Data System (ADS)

    Nave, L. E.; Vogel, C. S.; Gough, C. M.; Curtis, P. S.

    2006-12-01

    Nitrogen (N) limits net primary productivity (NPP) in most forests. Nearly all N required for NPP comes from decomposing organic matter, and is continuously recycled within the forest. However, atmospheric N deposition may augment forest N supply, increasing NPP. To quantify internal N cycling, atmospheric N inputs, and NPP, we developed an ecosystem-scale nitrogen (N) budget for a mixed deciduous forest in northern lower Michigan, USA. Sources of N were net N-mineralization (Nmin), wet (Dw) and bulk (Db) atmospheric N deposition, and canopy retention of bulk N deposition (CRN). We also quantified the N requirement of NPP, which was measured by biometric inventory of annual leaf, above- and belowground wood, and fine root mass production. Nmin supplied 44.3 kg N ha-1 yr-1 (88% of total annual N supply), while inorganic Dw supplied 4.8 kg N ha-1yr-1 (9% of total). Bulk organic N deposition contributed 1.5 kg N ha-1, or 3% of the total annual N supply. The forest canopy retained 2.2 kg N ha-1 of total Db, suggesting that 4% of the annual NPP N requirement could be met through canopy N uptake, if all N retained by the canopy was assimilated. Of the 53.5 kg N ha-1 yr-1 required for NPP, 61% was for fine root production, 32% was for leaf production, and 7% was for wood. Our N supply and forest NPP N requirement estimates were very close, with quantified N sources supplying 94% of the annual NPP N requirement. At our site, where Dw and organic Db provide 12% of the annual NPP N requirement, atmospheric N deposition makes a small but significant contribution to NPP. However, the minor contribution of CRN to the annual NPP N requirement indicates that N retained by the canopy has little effect on forest growth.

  14. Belowground Response to Drought in a Tropical Forest Soil. I. Changes in Microbial Functional Potential and Metabolism

    DOE PAGESBeta

    Bouskill, Nicholas J.; Wood, Tana E.; Baran, Richard; Ye, Zaw; Bowen, Benjamin P.; Lim, HsiaoChien; Zhou, Jizhong; Nostrand, Joy D. Van; Nico, Peter; Northen, Trent R.; et al

    2016-04-20

    We report that global climate models predict a future of increased severity of drought in many tropical forests. Soil microbes are central to the balance of these systems as sources or sinks of atmospheric carbon (C), yet how they respond metabolically to drought is not well-understood. We simulated drought in the typically aseasonal Luquillo Experimental Forest, Puerto Rico, by intercepting precipitation falling through the forest canopy. This approach reduced soil moisture by 13% and water potential by 0.14 MPa (from -0.2 to -0.34). Previous results from this experiment have demonstrated that the diversity and composition of these soil microbial communitiesmore » are sensitive to even small changes in soil water. Here, we show prolonged drought significantly alters the functional potential of the community and provokes a clear osmotic stress response, including the production of compatible solutes that increase intracellular C demand. Subsequently, a microbial population emerges with a greater capacity for extracellular enzyme production targeting macromolecular carbon. Significantly, some of these drought-induced functional shifts in the soil microbiota are attenuated by prior exposure to a short-term drought suggesting that acclimation may occur despite a lack of longer-term drought history.« less

  15. Belowground Response to Drought in a Tropical Forest Soil. I. Changes in Microbial Functional Potential and Metabolism.

    PubMed

    Bouskill, Nicholas J; Wood, Tana E; Baran, Richard; Ye, Zaw; Bowen, Benjamin P; Lim, HsiaoChien; Zhou, Jizhong; Nostrand, Joy D Van; Nico, Peter; Northen, Trent R; Silver, Whendee L; Brodie, Eoin L

    2016-01-01

    Global climate models predict a future of increased severity of drought in many tropical forests. Soil microbes are central to the balance of these systems as sources or sinks of atmospheric carbon (C), yet how they respond metabolically to drought is not well-understood. We simulated drought in the typically aseasonal Luquillo Experimental Forest, Puerto Rico, by intercepting precipitation falling through the forest canopy. This approach reduced soil moisture by 13% and water potential by 0.14 MPa (from -0.2 to -0.34). Previous results from this experiment have demonstrated that the diversity and composition of these soil microbial communities are sensitive to even small changes in soil water. Here, we show prolonged drought significantly alters the functional potential of the community and provokes a clear osmotic stress response, including the production of compatible solutes that increase intracellular C demand. Subsequently, a microbial population emerges with a greater capacity for extracellular enzyme production targeting macromolecular carbon. Significantly, some of these drought-induced functional shifts in the soil microbiota are attenuated by prior exposure to a short-term drought suggesting that acclimation may occur despite a lack of longer-term drought history. PMID:27148214

  16. Belowground Response to Drought in a Tropical Forest Soil. I. Changes in Microbial Functional Potential and Metabolism

    PubMed Central

    Bouskill, Nicholas J.; Wood, Tana E.; Baran, Richard; Ye, Zaw; Bowen, Benjamin P.; Lim, HsiaoChien; Zhou, Jizhong; Nostrand, Joy D. Van; Nico, Peter; Northen, Trent R.; Silver, Whendee L.; Brodie, Eoin L.

    2016-01-01

    Global climate models predict a future of increased severity of drought in many tropical forests. Soil microbes are central to the balance of these systems as sources or sinks of atmospheric carbon (C), yet how they respond metabolically to drought is not well-understood. We simulated drought in the typically aseasonal Luquillo Experimental Forest, Puerto Rico, by intercepting precipitation falling through the forest canopy. This approach reduced soil moisture by 13% and water potential by 0.14 MPa (from -0.2 to -0.34). Previous results from this experiment have demonstrated that the diversity and composition of these soil microbial communities are sensitive to even small changes in soil water. Here, we show prolonged drought significantly alters the functional potential of the community and provokes a clear osmotic stress response, including the production of compatible solutes that increase intracellular C demand. Subsequently, a microbial population emerges with a greater capacity for extracellular enzyme production targeting macromolecular carbon. Significantly, some of these drought-induced functional shifts in the soil microbiota are attenuated by prior exposure to a short-term drought suggesting that acclimation may occur despite a lack of longer-term drought history. PMID:27148214

  17. Forests synchronize their growth in contrasting Eurasian regions in response to climate warming.

    PubMed

    Shestakova, Tatiana A; Gutiérrez, Emilia; Kirdyanov, Alexander V; Camarero, Jesús Julio; Génova, Mar; Knorre, Anastasia A; Linares, Juan Carlos; Resco de Dios, Víctor; Sánchez-Salguero, Raúl; Voltas, Jordi

    2016-01-19

    Forests play a key role in the carbon balance of terrestrial ecosystems. One of the main uncertainties in global change predictions lies in how the spatiotemporal dynamics of forest productivity will be affected by climate warming. Here we show an increasing influence of climate on the spatial variability of tree growth during the last 120 y, ultimately leading to unprecedented temporal coherence in ring-width records over wide geographical scales (spatial synchrony). Synchrony in growth patterns across cold-constrained (central Siberia) and drought-constrained (Spain) Eurasian conifer forests have peaked in the early 21st century at subcontinental scales (∼ 1,000 km). Such enhanced synchrony is similar to that observed in trees co-occurring within a stand. In boreal forests, the combined effects of recent warming and increasing intensity of climate extremes are enhancing synchrony through an earlier start of wood formation and a stronger impact of year-to-year fluctuations of growing-season temperatures on growth. In Mediterranean forests, the impact of warming on synchrony is related mainly to an advanced onset of growth and the strengthening of drought-induced growth limitations. Spatial patterns of enhanced synchrony represent early warning signals of climate change impacts on forest ecosystems at subcontinental scales. PMID:26729860

  18. Forests synchronize their growth in contrasting Eurasian regions in response to climate warming

    PubMed Central

    Shestakova, Tatiana A.; Gutiérrez, Emilia; Kirdyanov, Alexander V.; Camarero, Jesús Julio; Génova, Mar; Knorre, Anastasia A.; Linares, Juan Carlos; Sánchez-Salguero, Raúl; Voltas, Jordi

    2016-01-01

    Forests play a key role in the carbon balance of terrestrial ecosystems. One of the main uncertainties in global change predictions lies in how the spatiotemporal dynamics of forest productivity will be affected by climate warming. Here we show an increasing influence of climate on the spatial variability of tree growth during the last 120 y, ultimately leading to unprecedented temporal coherence in ring-width records over wide geographical scales (spatial synchrony). Synchrony in growth patterns across cold-constrained (central Siberia) and drought-constrained (Spain) Eurasian conifer forests have peaked in the early 21st century at subcontinental scales (∼1,000 km). Such enhanced synchrony is similar to that observed in trees co-occurring within a stand. In boreal forests, the combined effects of recent warming and increasing intensity of climate extremes are enhancing synchrony through an earlier start of wood formation and a stronger impact of year-to-year fluctuations of growing-season temperatures on growth. In Mediterranean forests, the impact of warming on synchrony is related mainly to an advanced onset of growth and the strengthening of drought-induced growth limitations. Spatial patterns of enhanced synchrony represent early warning signals of climate change impacts on forest ecosystems at subcontinental scales. PMID:26729860

  19. Spatial climate-dependent growth response of boreal mixedwood forest in western Canada

    NASA Astrophysics Data System (ADS)

    Jiang, Xinyu; Huang, Jian-Guo; Stadt, Kenneth J.; Comeau, Philip G.; Chen, Han Y. H.

    2016-04-01

    The western Canadian mixedwood boreal forests were projected to be significantly affected by regional drought. However, drought degrees were spatially different across elevations, longitudes and latitudes, which might cause different tree growth responses to climate change in different sub-regions within western Canada. In this way, regional classification of western Canadian boreal forests and understanding spatial tree growth responses to climate might be necessary for future forest management and monitoring. In this paper, tree-ring chronologies of two dominant tree species, trembling aspen (Populus tremuloides Michx.) and white spruce (Picea glauca (Moench.) Voss), were obtained from mixed forest stands distributed across western Canada to study spatial tree growth response to climate based on three regional classification schemes (a phytogeographic sub-region classification, a natural sub-region classification and non-classification). Phytogeographic sub-region classification was estimated based on tree ring samples we collected in this study, while natural sub-region classification was previously developed based on analysis of regional differences in vegetation, soil, site and climate conditions. Results showed that air temperature did not significantly increase, while drought stress became more severe between 1985 to 2010. Relationships between trembling aspen growth and temperature differed between north and south parts of the study area, resulting from spatial difference in water supply. Trembling aspen growth was influenced by temperature or moisture variables of the previous years. White spruce growth was influenced primarily by moisture variables (current or previous year), and response coefficients between white spruce and drought conditions (represented by drought code) were negative in all phytogeographic sub-regions, suggesting that white spruce was more sensitive to drought stress under climate change. As a late-successional dominant species

  20. Alpine forest-tundra ecotone response to temperature change,Sayan Mountains, Siberia

    NASA Technical Reports Server (NTRS)

    Ranson, K Jon; Kharuk, Vyetcheslav I.

    2007-01-01

    Models of climate change predict shifts of vegetation zones. Tree response to climate trends is most likely observable in the forest-tundra ecotone, where temperature mainly limits tree growth. There is evidence of vegetation change on the northern treeline However, observations on alpine tree line response are controversial. In this NEESPI related study we show that during the past three decades in the forest-tundra ecotone of the Sayan Mountains, Siberia, there was an increase in forest stand crown closure, regeneration propagation into the alpine tundra, and transformation of prostrate Siberian pine and fir into arboreal forms. We found that these changes occurred since the mid 1980s, and strongly correlates with positive temperature (and to a lesser extent, precipitation) trends. Improving climate for forest growth( i.e., warmer temperatures and increased precipitation) provides competitive advantages to Siberian pine in the alpine forest-tundra ecotone, as well as in areas typically dominated by larch, where it has been found to be forming a secondary canopy layer. Substitution of deciduous conifer, larch, for evergreen conifers, decreases albedo and provides positive feedback for temperature increase.

  1. Interactions among forest age, valley and channel morphology, and log jams regulate animal production in mountain streams

    NASA Astrophysics Data System (ADS)

    Walters, D. M.; Venarsky, M. P.; Hall, R. O., Jr.; Herdrich, A.; Livers, B.; Winkelman, D.; Wohl, E.

    2014-12-01

    Forest age and local valley morphometry strongly influence the form and function of mountain streams in Colorado. Streams in valleys with old growth forest (>350 years) have extensive log jam complexes that create multi-thread channel reaches with extensive pool habitat and large depositional areas. Streams in younger unmanaged forests (e.g., 120 years old) and intensively managed forests have much fewer log jams and lower wood loads. These are single-thread streams dominated by riffles and with little depositional habitat. We hypothesized that log jam streams would retain more organic matter and have higher metabolism, leading to greater production of stream macroinvertebrates and trout. Log jam reaches should also have greater emergence of adult aquatic insects, and consequently have higher densities of riparian spiders taking advantage of these prey. Surficial organic matter was 3-fold higher in old-growth streams, and these streams had much higher ecosystem respiration. Insect production (g m2 y-1) was similar among forest types, but fish density was four times higher in old-growth streams with copious log jams. However, at the valley scale, insect production (g m-1 valley-1) and trout density (number m-1 valley-1) was 2-fold and 10-fold higher, respectively, in old growth streams. This finding is because multi-thread reaches created by log jams have much greater stream area and stream length per meter of valley than single-thread channels. The more limited response of macroinvertebrates may be related to fish predation. Trout in old growth streams had similar growth rates and higher fat content than fish in other streams in spite of occurring at higher densities and higher elevation/colder temperatures. This suggests that the positive fish effect observed in old growth streams is related to greater availability of invertebrate prey, which is consistent with our original hypothesis. Preliminary analyses suggest that spider densities do not respond strongly to

  2. Proximity to forest edge does not affect crop production despite pollen limitation

    PubMed Central

    Chacoff, Natacha P; Aizen, Marcelo A; Aschero, Valeria

    2008-01-01

    A decline in pollination function has been linked to agriculture expansion and intensification. In northwest Argentina, pollinator visits to grapefruit, a self-compatible but pollinator-dependent crop, decline by approximately 50% at 1 km from forest edges. We evaluated whether this decrease in visitation also reduces the pollination service in this crop. We analysed the quantity and quality of pollen deposited on stigmas, and associated limitation of fruit production at increasing distances (edge: 10, 100, 500 and 1000 m) from the remnants of Yungas forest. We also examined the quantitative and qualitative efficiency of honeybees as pollen vectors. Pollen receipt and pollen tubes in styles decreased with increasing distance from forest edge; however, this decline did not affect fruit production. Supplementation of natural pollen with self- and cross-pollen revealed that both pollen quantity and quality limited fruit production. Despite pollen limitation, honeybees cannot raise fruit production because they often do not deposit sufficient high-quality pollen per visit to elicit fruit development. However, declines in visitation frequency well below seven visits during a flower's lifespan could decrease production beyond current yields. In this context, the preservation of forest remnants, which act as pollinator sources, could contribute to resilience in crop production. Like wild plants, pollen limitation of the yield among animal-pollinated crops may be common and indicative not only of pollinator scarcity, but also of poor pollination quality, whereby pollinator efficiency, rather than just abundance, can play a broader role than previously appreciated. PMID:18230596

  3. Responses of forest cover and agricultural land changes to local and national drivers of land development in the Miombo Woodlands of western Tanzania

    NASA Astrophysics Data System (ADS)

    Mayes, M. T.; Mustard, J. F.; Melillo, J. M.

    2013-12-01

    Among dry tropical forest ecosystems globally, the Miombo Woodlands of western Tanzania have experienced extensive forest cover changes in the past two decades that remain poorly understood at regional (100s km2) spatial scales. Recent studies have associated large areas of forest loss in the Miombo with agricultural activities, such as increased tobacco cultivation since the 1990s. However, the dynamics of forest regrowth and net changes in forest cover have not been well characterized. Landscape phenology is complex due to high seasonal and inter-annual variability in vegetation productivity, forest structure, smallholder land use practices, and fire dynamics. Improved characterization of forest and agricultural land cover phenology is needed to use remote sensing more effectively for studying land changes in the Miombo. This project assesses patterns of forest loss and regrowth, and analyzes their relationships to climate, landscape biophysical factors, and agricultural policies and activities in Tabora Province in western Tanzania, from 1990-2013. We develop new satellite remote sensing methods for mapping dry tropical forest and non-forest land cover, based on differences in their seasonal phenology patterns in Landsat imagery quantified using spectral mixture analysis (SMA). Using z-score metrics on SMA fraction images, we find that forest regions have significantly lower sums of substrate and non-photosynthetic vegetation pixel fractions than non-forest regions. We validate our algorithm with field data from 2012-2013 and show that it provides reasonable estimates of forest and non-forest land cover in analyses of imagery from single or multiple dates. Our main objectives are to evaluate whether patterns of forest loss and regrowth show spatial relationships with localized land use practices and environmental factors, or if land changes reflect influences of national to global-scale drivers. For local drivers, we examine if areas of forest loss and regrowth

  4. Tree responses to hummock hydrology in a forested coastal swamp

    NASA Astrophysics Data System (ADS)

    Hsueh, Y. H.; Keim, R.; Krauss, K. W.; Chambers, J. L.

    2014-12-01

    Microtopographic controls on variability in growth stressors, such as salinity and flooding, may be crucial to some forested wetlands, especially because wetland trees generally occupy hummocks more frequently than swales. We quantified how elevation differences of less than one meter affect sources of water uptake by individual trees in the Mississippi River Delta, Louisiana. Salinity and naturally occurring stable isotopes of water were used as tracers of hydrologic and physiologic processes. Water samples were taken from tree xylem and soil at multiple depths across a range of drought and wet conditions. Hummocks were frequently but temporarily submerged after rainfall (total 9% of the time) and tides influenced inundation (every 46.9 hours). Isotopic composition of surface water and throughfall were similar, and were temporally more variable than was groundwater in hummocks. Salinity was lower but more temporally variable in the upper hummocks than in lower hummocks. Low deuterium excess indicated evaporative concentration in the unsaturated zone. Low deuterium excess (1.9 ± 2.1‰ below the local meteoric water line) and low temporal variability in groundwater suggested long residence time and limited exchange with surface water. The δD/δ18O ratio of xylem water (3.9) matched that of pore water in the unsaturated zone, showing that the water source for trees was the upper portion of hummocks. This study indicates that trees rely on hummocks as refuge from salinity in addition to reducing flood durations.

  5. Net mineralization of N at deeper soil depths as a potential mechanism for sustained forest production under elevated [CO2

    SciTech Connect

    Iversen, Colleen M; Hooker, Toby; Classen, Aimee T; Norby, Richard J

    2011-01-01

    Elevated atmospheric [CO2] is projected to increase forest production, which could increase ecosystem carbon (C) storage. However, sustained forest production will depend on the nutrient balance of the forested ecosystem. Our aim was to examine the causes and consequences of increased fine-root production and mortality throughout the soil profile under elevated CO2 with respect to potential gross nitrogen (N) cycling rates. Our study was conducted in a CO2-enriched sweetgum (Liquidambar styraciflua L.) plantation in Oak Ridge, TN, USA. We used isotope pool dilution methodology to measure potential gross N cycling rates in laboratory incubations of soil from four depth increments to 60 cm. Our objectives were two-fold: (1) determine whether N is available for root acquisition in deeper soil, and (2) determine whether increased inputs of labile C from greater fine-root mortality at depth under elevated [CO2] had altered N cycling rates. While gross N fluxes declined with soil depth, we found that N is potentially available for roots to access, especially below 15 cm depth where microbial consumption of mineral N was reduced. Overall, up to 60% of potential gross N mineralization, and 100% of potential net N mineralization, occurred below 15-cm depth at this site. This finding was supported by in situ measurements from ion-exchange resins, where total inorganic N availability at 55 cm depth was equal to or greater than N availability at 15 cm depth. While it is likely that trees grown under elevated [CO2] are accessing a larger pool of inorganic N by mining deeper soil, we found no effect of elevated [CO2] on potential gross or net N cycling rates. Thus, increased root exploration of the soil volume under elevated [CO2] may be more important than changes in potential gross N cycling rates in sustaining forest responses to rising atmospheric CO2.

  6. 36 CFR 223.101 - Determination of purchaser responsibility.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Determination of purchaser responsibility. 223.101 Section 223.101 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST...

  7. 36 CFR 223.101 - Determination of purchaser responsibility.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Determination of purchaser responsibility. 223.101 Section 223.101 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST...

  8. 36 CFR 223.101 - Determination of purchaser responsibility.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Determination of purchaser responsibility. 223.101 Section 223.101 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST...

  9. 36 CFR 223.101 - Determination of purchaser responsibility.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Determination of purchaser responsibility. 223.101 Section 223.101 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST...

  10. Berry production in three whitebark pine forest types

    USGS Publications Warehouse

    Weaver, T.; Kendall, K.C.; Forcella, F.

    1990-01-01

    In the whitebark pine /whortleberry (Pinus albicaulis/Vaccinium scoparium) habitat type of southwestern Montana, whortleberry plants produced seven to 69 berries/m2 x yr in 1974. In subalpine fir (Abies lasiocarpa) habitat types of northwestern Montana, huckleberry plants (Vaccinium globulare) may produce from 13 to 228 berries/m2 X yr. While removal of competing trees increases production, thinning the understory apparently reduces berry production in direct proportion to the shrubs removed; there is no compensatory production indicative of shrub-shrub competition in fully vegetated plots. Fifty-to 100-fold variation in production among years in Vaccinium globulare berry production is attributed to variation in weather conditions.

  11. The relationship between productivities of salmonids and forest stands in northern California watersheds

    USGS Publications Warehouse

    Frazey, S.L.; Wilzbach, M.A.

    2007-01-01

    Productivities of resident salmonids and upland and riporian forests in 22 small watersheds of coastal northern California were estimated and compared to determine whether: 1) upland site productivity predicted riparian site productivity; 2) either upland or riparian site productivity predicted salmonid productivity; and 3) other parameters explained more of the variance in salmonid productivity. Upland and riparian site productivities were estimated using Site Index values for redwood (Sequoia sempervirens) and red alder (Alnus rubra), respectively. Salmonid productivity was indexed by back-calculated length at age 1 of the largest individuals sampled and by total biomass. Upland and riparian site indices were correlated, but neither factor contributed to the best approximating models of salmonid productivity. Total salmonid biomass was best described by a positive relationship with drainage area. Length of dominant fish was best described by a positive relationship with percentage of hardwoods within riparian areas, which may result from nutrient and/or litter subsidies provided by red older. The inability of forest productivity to predict salmon productivity may reflect insufficient variation in independent variables, limitations of the indices, and the operation of other factors affecting salmonid production. The lack of an apparent relationship between upland conifer and salmonid productivity suggests that management of land for timber productivity and component streams for salmonid production in these sites will require separate, albeit integrated, management strategies.

  12. Maximizing Conservation and Production with Intensive Forest Management: It's All About Location.

    PubMed

    Tittler, Rebecca; Filotas, Élise; Kroese, Jasmin; Messier, Christian

    2015-11-01

    Functional zoning has been suggested as a way to balance the needs of a viable forest industry with those of healthy ecosystems. Under this system, part of the forest is set aside for protected areas, counterbalanced by intensive and extensive management of the rest of the forest. Studies indicate this may provide adequate timber while minimizing road construction and favoring the development of large mature and old stands. However, it is unclear how the spatial arrangement of intensive management areas may affect the success of this zoning. Should these areas be agglomerated or dispersed throughout the forest landscape? Should managers prioritize (a) proximity to existing roads, (b) distance from protected areas, or (c) site-specific productivity? We use a spatially explicit landscape simulation model to examine the effects of different spatial scenarios on landscape structure, connectivity for native forest wildlife, stand diversity, harvest volume, and road construction: (1) random placement of intensive management areas, and (2-8) all possible combinations of rules (a)-(c). Results favor the agglomeration of intensive management areas. For most wildlife species, connectivity was the highest when intensive management was far from the protected areas. This scenario also resulted in relatively high harvest volumes. Maximizing distance of intensive management areas from protected areas may therefore be the best way to maximize the benefits of intensive management areas while minimizing their potentially negative effects on forest structure and biodiversity. PMID:26076893

  13. Maximizing Conservation and Production with Intensive Forest Management: It's All About Location

    NASA Astrophysics Data System (ADS)

    Tittler, Rebecca; Filotas, Élise; Kroese, Jasmin; Messier, Christian

    2015-11-01

    Functional zoning has been suggested as a way to balance the needs of a viable forest industry with those of healthy ecosystems. Under this system, part of the forest is set aside for protected areas, counterbalanced by intensive and extensive management of the rest of the forest. Studies indicate this may provide adequate timber while minimizing road construction and favoring the development of large mature and old stands. However, it is unclear how the spatial arrangement of intensive management areas may affect the success of this zoning. Should these areas be agglomerated or dispersed throughout the forest landscape? Should managers prioritize (a) proximity to existing roads, (b) distance from protected areas, or (c) site-specific productivity? We use a spatially explicit landscape simulation model to examine the effects of different spatial scenarios on landscape structure, connectivity for native forest wildlife, stand diversity, harvest volume, and road construction: (1) random placement of intensive management areas, and (2-8) all possible combinations of rules (a)-(c). Results favor the agglomeration of intensive management areas. For most wildlife species, connectivity was the highest when intensive management was far from the protected areas. This scenario also resulted in relatively high harvest volumes. Maximizing distance of intensive management areas from protected areas may therefore be the best way to maximize the benefits of intensive management areas while minimizing their potentially negative effects on forest structure and biodiversity.

  14. Future Forest Production and Net Carbon Sinks under Optimal C:N Balance

    NASA Astrophysics Data System (ADS)

    Makela, A.; Kalliokoski, T.; Peltoniemi, M.

    2014-12-01

    Environmental change affects forests directly by changing physiological process rates, but the consequent changes in resource acquisition may lead to structural and functional acclimations that obscure the long-term relationship between environmental drivers and forest function. Based on an adaptive balance between structure and function, evolutionary optimisation may provide a feasible tool for analysing such indirect effects of environmental change on forests. This study applies OptiPipe, a model of optimal co-allocation of forest carbon (C) and nitrogen (N), to prediction of potential productivity and C balance of Finnish forests under climate change. OptiPipe is embedded in a transparent modular system including: PreLes, a canopy C exchange model; Yasso, a soil C model; and expert assumptions about the impacts of weather on N availability at different growth sites. National Forest Inventory data and gridded weather data (10 x 10 km2) are utilised. The uncertainties of the projections are analysed relative to inputs and parameters. The results quantify the changes in growth and carbon stocks, which are either smaller or larger than those in photosynthetic capacity, depending on the C:N balance of the site. The results emphasize the need to obtain more reliable information and data about nitrogen processes, but also demonstrate the potential for the optimality approach for regional applications.

  15. Above- and below-ground net primary productivity across ten Amazonian forests on contrasting soils

    NASA Astrophysics Data System (ADS)

    Aragão, L. E. O. C.; Malhi, Y.; Metcalfe, D. B.; Silva-Espejo, J. E.; Jiménez, E.; Navarrete, D.; Almeida, S.; Costa, A. C. L.; Salinas, N.; Phillips, O. L.; . Anderson, L. O.; Baker, T. R.; Goncalvez, P. H.; Huamán-Ovalle, J.; Mamani-Solórzano, M.; Meir, P.; Monteagudo, A.; Peñuela, M. C.; Prieto, A.; Quesada, C. A.; Rozas-Dávila, A.; Rudas, A.; Silva Junior, J. A.; Vásquez, R.

    2009-02-01

    The net primary productivity (NPP) of tropical forests is one of the most important and least quantified components of the global carbon cycle. Most relevant studies have focused particularly on the quantification of the above-ground coarse wood productivity, and little is known about the carbon fluxes involved in other elements of the NPP, the partitioning of total NPP between its above- and below-ground components and the main environmental drivers of these patterns. In this study we quantify the above- and below-ground NPP of ten Amazonian forests to address two questions: (1) How do Amazonian forests allocate productivity among its above- and below-ground components? (2) How do soil and leaf nutrient status and soil texture affect the productivity of Amazonian forests? Using a standardized methodology to measure the major elements of productivity, we show that NPP varies between 9.3±1.3 Mg C ha-1 yr-1 (mean±standard error), at a white sand plot, and 17.0±1.4 Mg C ha-1 yr-1 at a very fertile Terra Preta site, with an overall average of 12.8±0.9 Mg C ha-1 yr-1. The studied forests allocate on average 64±3% and 36±3% of the total NPP to the above- and below-ground components, respectively. The ratio of above-ground and below-ground NPP is almost invariant with total NPP. Litterfall and fine root production both increase with total NPP, while stem production shows no overall trend. Total NPP tends to increase with soil phosphorus and leaf nitrogen status. However, allocation of NPP to below-ground shows no relationship to soil fertility, but appears to decrease with the increase of soil clay content.

  16. Above- and below-ground net primary productivity across ten Amazonian forests on contrasting soils

    NASA Astrophysics Data System (ADS)

    Aragão, L. E. O. C.; Malhi, Y.; Metcalfe, D. B.; Silva-Espejo, J. E.; Jiménez, E.; Navarrete, D.; Almeida, S.; Costa, A. C. L.; Salinas, N.; Phillips, O. L.; Anderson, L. O.; Alvarez, E.; Baker, T. R.; Goncalvez, P. H.; Huamán-Ovalle, J.; Mamani-Solórzano, M.; Meir, P.; Monteagudo, A.; Patiño, S.; Peñuela, M. C.; Prieto, A.; Quesada, C. A.; Rozas-Dávila, A.; Rudas, A.; Silva, J. A., Jr.; Vásquez, R.

    2009-12-01

    The net primary productivity (NPP) of tropical forests is one of the most important and least quantified components of the global carbon cycle. Most relevant studies have focused particularly on the quantification of the above-ground coarse wood productivity, and little is known about the carbon fluxes involved in other elements of the NPP, the partitioning of total NPP between its above- and below-ground components and the main environmental drivers of these patterns. In this study we quantify the above- and below-ground NPP of ten Amazonian forests to address two questions: (1) How do Amazonian forests allocate productivity among its above- and below-ground components? (2) How do soil and leaf nutrient status and soil texture affect the productivity of Amazonian forests? Using a standardized methodology to measure the major elements of productivity, we show that NPP varies between 9.3±1.3 Mg C ha-1 yr-1 (mean±standard error), at a white sand plot, and 17.0±1.4 Mg C ha-1 yr-1 at a very fertile Terra Preta site, with an overall average of 12.8±0.9 Mg C ha-1 yr-1. The studied forests allocate on average 64±3% and 36±3% of the total NPP to the above- and below-ground components, respectively. The ratio of above-ground and below-ground NPP is almost invariant with total NPP. Litterfall and fine root production both increase with total NPP, while stem production shows no overall trend. Total NPP tends to increase with soil phosphorus and leaf nitrogen status. However, allocation of NPP to below-ground shows no relationship to soil fertility, but appears to decrease with the increase of soil clay content.

  17. Competition-interaction landscapes for the joint response of forests to climate change.

    PubMed

    Clark, James S; Bell, David M; Kwit, Matthew C; Zhu, Kai

    2014-06-01

    The recent global increase in forest mortality episodes could not have been predicted from current vegetation models that are calibrated to regional climate data. Physiological studies show that mortality results from interactions between climate and competition at the individual scale. Models of forest response to climate do not include interactions because they are hard to estimate and require long-term observations on individual trees obtained at frequent (annual) intervals. Interactions involve multiple tree responses that can only be quantified if these responses are estimated as a joint distribution. A new approach provides estimates of climate–competition interactions in two critical ways, (i) among individuals, as a joint distribution of responses to combinations of inputs, such as resources and climate, and (ii) within individuals, due to allocation requirements that control outputs, such as demographic rates. Application to 20 years of data from climate and competition gradients shows that interactions control forest responses, and their omission from models leads to inaccurate predictions. Species most vulnerable to increasing aridity are not those that show the largest growth response to precipitation, but rather depend on interactions with the local resource environment. This first assessment of regional species vulnerability that is based on the scale at which climate operates, individual trees competing for carbon and water, supports predictions of potential savannification in the southeastern US. PMID:24932467

  18. Flood response for the watersheds of the Fernow Experimental Forest in the central Appalachians

    NASA Astrophysics Data System (ADS)

    Bates, Naomi S.; Smith, James A.; Villarini, Gabriele

    2015-06-01

    We examine flood response of high-gradient, forested central Appalachian watersheds through analyses of rainfall, streamflow, and piezometer observations from the Fernow Experimental Forest near Parsons, West Virginia. Analyses focus on hydrologic processes that control the "upper tail" of flood distributions. The largest flood peaks in the Fernow are an order of magnitude smaller than record floods in the central Appalachian region (for basins of comparable drainage area). We examine flood distributions in the Fernow using extreme value distributions (Generalized Extreme Value and Generalized Pareto distributions) and compare them to other watersheds in the central Appalachians. To examine the role of antecedent soil moisture on flood response, we installed a network of 415 crest-stage piezometers on two headwater watersheds (0.30 and 0.14 km2) of the Fernow. Observations show pronounced heterogeneity of subsurface saturation even within the unchannelized swales of headwater watersheds. Shallow perched water tables over large portions of a watershed occur infrequently in forested central Appalachian basins, but may play an important role in extreme flood response. Fernow watersheds include "treated" and control watersheds with stream gaging records extending back to 1951. We examine nonstationarites in flood frequency in the Fernow and show that forest management practices have had relatively minor impacts on flood frequency.

  19. Effects of morphology on the micro-compression response of carbon nanotube forests

    NASA Astrophysics Data System (ADS)

    Shahid Saeed Abadi, Parisa Pour; Hutchens, Shelby B.; Greer, Julia R.; Cola, Baratunde A.; Graham, Samuel

    2012-05-01

    This study reports the mechanical response of distinct carbon nanotube (CNT) morphologies as revealed by flat punch in situ nanoindentation in a scanning electron microscope. We find that the location of incipient deformation varies significantly by changing the CNT growth parameters. The initial buckles formed close to the growth substrate in 70 and 190 μm tall CNT forests grown with low pressure chemical vapor deposition (LPCVD) and moved to ~100 μm above the growth substrate when the height increased to 280 μm. Change of the recipe from LPCVD to CVD at pressures near atmospheric changed the location of the initial buckling event from the bottom half to the top half of the CNT forest. Plasma pretreatment of the catalyst also resulted in a unique CNT forest morphology in which deformation started by bending and buckling of the CNT tips. We find that the vertical gradients in CNT morphology dictate the location of incipient buckling. These new insights are critical in the design of CNT forests for a variety of applications where mechanical contact is important.This study reports the mechanical response of distinct carbon nanotube (CNT) morphologies as revealed by flat punch in situ nanoindentation in a scanning electron microscope. We find that the location of incipient deformation varies significantly by changing the CNT growth parameters. The initial buckles formed close to the growth substrate in 70 and 190 μm tall CNT forests grown with low pressure chemical vapor deposition (LPCVD) and moved to ~100 μm above the growth substrate when the height increased to 280 μm. Change of the recipe from LPCVD to CVD at pressures near atmospheric changed the location of the initial buckling event from the bottom half to the top half of the CNT forest. Plasma pretreatment of the catalyst also resulted in a unique CNT forest morphology in which deformation started by bending and buckling of the CNT tips. We find that the vertical gradients in CNT morphology dictate the

  20. Climate and Management Controls on Forest Growth and Forest Carbon Balance in the Western United States

    NASA Astrophysics Data System (ADS)

    Kelsey, Katharine Cashman

    Climate change is resulting in a number of rapid changes in forests worldwide. Forests comprise a critical component of the global carbon cycle, and therefore climate-induced changes in forest carbon balance have the potential to create a feedback within the global carbon cycle and affect future trajectories of climate change. In order to further understanding of climate-driven changes in forest carbon balance, I (1) develop a method to improve spatial estimates forest carbon stocks, (2) investigate the effect of climate change and forest management actions on forest recovery and carbon balance following disturbance, and (3) explore the relationship between climate and forest growth, and identify climate-driven trends in forest growth through time, within San Juan National Forest in southwest Colorado, USA. I find that forest carbon estimates based on texture analysis from LandsatTM imagery improve regional forest carbon maps, and this method is particularly useful for estimating carbon stocks in forested regions affected by disturbance. Forest recovery from disturbance is also a critical component of future forest carbon stocks, and my results indicate that both climate and forest management actions have important implications for forest recovery and carbon dynamics following disturbance. Specifically, forest treatments that use woody biomass removed from the forest for electricity production can reduce carbon emissions to the atmosphere, but climate driven changes in fire severity and forest recovery can have the opposite effect on forest carbon stocks. In addition to the effects of disturbance and recovery on forest condition, I also find that climate change is decreasing rates of forest growth in some species, likely in response to warming summer temperatures. These growth declines could result in changes of vegetation composition, or in extreme cases, a shift in vegetation type that would alter forest carbon storage. This work provides insight into both

  1. Plasticity in response to phosphorus and light availability in four forest herbs.

    PubMed

    Baeten, Lander; Vanhellemont, Margot; De Frenne, Pieter; De Schrijver, An; Hermy, Martin; Verheyen, Kris

    2010-08-01

    The differential ability of forest herbs to colonize secondary forests on former agricultural land is generally attributed to different rates of dispersal. After propagule arrival, however, establishing individuals still have to cope with abiotic soil legacies from former agricultural land use. We focused on the plastic responses of forest herbs to increased phosphorus availability, as phosphorus is commonly found to be persistently bioavailable in post-agricultural forest soils. In a pot experiment performed under field conditions, we applied three P levels to four forest herbs with contrasting colonization capacities: Anemone nemorosa, Primula elatior, Circaea lutetiana and Geum urbanum. To test interactions with light availability, half of the replicas were covered with shade cloths. After two growing seasons, we measured aboveground P uptake as well as vegetative and regenerative performance. We hypothesized that fast-colonizing species respond the most opportunistically to increased P availability, and that a low light availability can mask the effects of P on performance. All species showed a significant increase in P uptake in the aboveground biomass. The addition of P had a positive effect on the vegetative performances of two of the species, although this was unrelated to their colonization capacities. The regenerative performance was affected by light availability (not by P addition) and was related to the species' phenology. Forest herbs can obviously benefit from the increased availability of P in post-agricultural forests, but not all species respond in the same way. Such differential patterns of plasticity may be important in community dynamics, as they affect the interactions among species. PMID:20300776

  2. Epigenetic regulation of adaptive responses of forest tree species to the environment

    PubMed Central

    Bräutigam, Katharina; Vining, Kelly J; Lafon-Placette, Clément; Fossdal, Carl G; Mirouze, Marie; Marcos, José Gutiérrez; Fluch, Silvia; Fraga, Mario Fernández; Guevara, M Ángeles; Abarca, Dolores; Johnsen, Øystein; Maury, Stéphane; Strauss, Steven H; Campbell, Malcolm M; Rohde, Antje; Díaz-Sala, Carmen; Cervera, María-Teresa

    2013-01-01

    Epigenetic variation is likely to contribute to the phenotypic plasticity and adaptative capacity of plant species, and may be especially important for long-lived organisms with complex life cycles, including forest trees. Diverse environmental stresses and hybridization/polyploidization events can create reversible heritable epigenetic marks that can be transmitted to subsequent generations as a form of molecular “memory”. Epigenetic changes might also contribute to the ability of plants to colonize or persist in variable environments. In this review, we provide an overview of recent data on epigenetic mechanisms involved in developmental processes and responses to environmental cues in plant, with a focus on forest tree species. We consider the possible role of forest tree epigenetics as a new source of adaptive traits in plant breeding, biotechnology, and ecosystem conservation under rapid climate change. PMID:23467802

  3. Across a macro-ecological gradient forest competition is strongest at the most productive sites.

    PubMed

    Prior, Lynda D; Bowman, David M J S

    2014-01-01

    We tested the hypothesis that the effect of forest basal area on tree growth interacts with macro-ecological gradients of primary productivity, using a large dataset of eucalypt tree growth collected across temperate and sub- tropical mesic Australia. To do this, we derived an index of inter-tree competition based on stand basal area (stand BA) relative to the climatically determined potential basal area. Using linear mixed effects modeling, we found that the main effects of climatic productivity, tree size, and competition explained 26.5% of the deviance in individual tree growth, but adding interactions to the model could explain a further 8.9%. The effect of competition on growth interacts with the gradient of climatic productivity, with negligible effect of competition in low productivity environments, but marked negative effects at the most productive sites. We also found a positive interaction between tree size and stand BA, which was most pronounced in the most productive sites. We interpret these patterns as reflecting intense competition for light amongst maturing trees on more productive sites, and below ground moisture limitation at low productivity sites, which results in open stands with little competition for light. These trends are consistent with the life history and stand development of eucalypt forests: in cool moist environments, light is the most limiting resource, resulting in size-asymmetric competition, while in hot, low rainfall environments are open forests with little competition for light but where the amount of tree regeneration is limited by water availability. PMID:24926304

  4. RESPONSES AND FEEDBACK TO GLOBAL FORESTS TO CLIMATE CHANGE

    EPA Science Inventory

    The accumulation of greenhouse gases in the atmosphere over the past century is projected to cause a warming of the Earth. limate change predictions vary by region and terrestrial biosphere response and feedbacks will be ecosystem specific. orests play a major role in the earth's...

  5. Hydro-economic modeling of the role of forests on water resources production in Andalusia, Spain

    NASA Astrophysics Data System (ADS)

    Beguería, Santiago; Serrano-Notivoli, Roberto; Álvarez-Palomino, Alejandro; Campos, Pablo

    2014-05-01

    The development of more refined information tools is a pre-requisite for supporting decision making in the context of integrated water resources management. Among these tools, hydro-economic models are favoured because they allow integrating the ecological, hydrological, infrastructure and economic aspects into a coherent, scientifically-informed framework. We present a case study that assesses physically the water resources of forest lands of the Andalusia region in Spain and conducts an economic environmental income and asset valuation of the forest surface water yield. We show how, based on available hydrologic and economic data, we can develop a comprehensive water account for all the forest lands at the regional scale. This forest water environmental valuation is part of the larger RECAMAN project, which aims at providing a robust and easily replicable accounting tool to evaluate yearly the total income an capital generated by the forest land, encompassing all measurable sources of private and public incomes (timber and cork production, auto-consumption, recreational activities, biodiversity conservation, carbon sequestration, water production, etc.). Only a comprehensive integrated tool such as the one built within the RECAMAN project may serve as a basis for the development of integrated policies such as those internationally agreed and recommended for the management of water resources.

  6. Response of high-elevation forests in the Olympic Mountains to climatic change

    USGS Publications Warehouse

    Zolbrod, A.N.; Peterson, D.L.

    1999-01-01

    The gap model ZELIG was used to examine the effects of increased temperature (2A?C) and altered precipitation on high-elevation ecosystems of the Olympic Mountains, Washington, U.S.A. Changes in tree species distribution and abundance, as well as stand biomass, were examined on north and south aspects in the dry northeast (NE) and wet southwest (SW) regions of the Olympics for (i) warmer, (ii) warmer and 20% wetter, and (iii) warmer and 20% drier climatic-change scenarios. Dominant tree species shift upwards 300-600 m in elevation in the SW, with subalpine meadows and Tsuga mertensiana (Bong.) Carr. forests being replaced by Abies amabilis (Dougl.) Forbes forests at higher elevations and A. amabilis forests being replaced by Tsuga heterophylla (Raf.) Sarg. forests at lower elevations. In the NE, drought-tolerant species become dominant approximately 200 m lower than present, with A. lasiocarpa dominating the north aspect and Pinus contorta Dougl. ex Loud. the south aspect. Biomass increases in the SW and generally decreases in the NE, depending on aspect and precipitation regime. This study suggests that species and site-specific responses at mesoscale (e.g., wet vs. dry climatic regime) and microscale (e.g., north vs. south aspect) resolutions must be characterized to quantify the variation in potential effects of climatic change on forest vegetation in mountainous regions.

  7. Divergent stakeholder views of corporate social responsibility in the Australian forest plantation sector.

    PubMed

    Gordon, Melissa; Lockwood, Michael; Vanclay, Frank; Hanson, Dallas; Schirmer, Jacki

    2012-12-30

    Although the Australian forest plantation industry acknowledges that there is a role for corporate social responsibility (CSR) in forest management, there is confusion as to what this constitutes in practice. This paper describes the conflicts between internal and external stakeholder views on CSR in plantation forestry. We conducted in-depth interviews with key informants across three plantation management regions in Australia: Tasmania, the Green Triangle and south-west Western Australia. We interviewed a range of stakeholders including forest company employees, local councils, Indigenous representatives, and environmental non-government organisations. CSR-related initiatives that stakeholders believed were important for plantation management included the need for community engagement, accountability towards stakeholders, and contribution to community development and well-being. Although there was wide support for these initiatives, some stakeholders were not satisfied that forest companies were actively implementing them. Due to the perception that forest companies are not committed to CSR initiatives such as community engagement, some stakeholder expectations are not being satisfied. PMID:23078976

  8. Estimation of tropical forest canopy temperatures, thermal response numbers, and evapotranspiration using an aircraft-based thermal sensor

    NASA Technical Reports Server (NTRS)

    Luvall, Jeffrey C.; Lieberman, Diana; Lieberman, Milton; Hartshorn, Gary S.; Peralta, Rodolfo

    1990-01-01

    Thermal infrared Multispectral Scanner (TIMS) data were collected at a resolution of 5 to 10 m from a tropical rain forest over an elevation gradient from 35 to 2700 m in the Braulio Carrillo National Park in Costa Rica. Flight lines were repeated with a 15 to 30 minute time difference for measurement of forest canopy thermal response over time. Concurrent radiosonde measurements of atmospheric profiles of air temperature and moisture provided inputs to LOWTRAN6 for atmospheric radiance corrections of the TIMS data. Techniques for using calibrated aircraft-based thermal scanner data to examine tropical forest canopy thermal properties are described. Forest canopy temperature changes over time assessed between repeated, duplicated flight lines were combined with estimates of surface radiative energy measurements from towers above the forest canopy to determine temperature spatial variability, calculate Thermal Response Numbers (TRN), and estimate evapotranspiration along the elevation gradient from selected one hectare forest inventory plots.

  9. Plant response to climate change along the forest-tundra ecotone in northeastern Siberia.

    PubMed

    Berner, Logan T; Beck, Pieter S A; Bunn, Andrew G; Goetz, Scott J

    2013-11-01

    Russia's boreal (taiga) biome will likely contract sharply and shift northward in response to 21st century climatic change, yet few studies have examined plant response to climatic variability along the northern margin. We quantified climate dynamics, trends in plant growth, and growth-climate relationships across the tundra shrublands and Cajander larch (Larix cajanderi Mayr.) woodlands of the Kolyma river basin (657 000 km(2) ) in northeastern Siberia using satellite-derived normalized difference vegetation indices (NDVI), tree ring-width measurements, and climate data. Mean summer temperatures (Ts ) increased 1.0 °C from 1938 to 2009, though there was no trend (P > 0.05) in growing year precipitation or climate moisture index (CMIgy ). Mean summer NDVI (NDVIs ) increased significantly from 1982 to 2010 across 20% of the watershed, primarily in cold, shrub-dominated areas. NDVIs positively correlated (P < 0.05) with Ts across 56% of the watershed (r = 0.52 ± 0.09, mean ± SD), principally in cold areas, and with CMIgy across 9% of the watershed (r = 0.45 ± 0.06), largely in warm areas. Larch ring-width measurements from nine sites revealed that year-to-year (i.e., high-frequency) variation in growth positively correlated (P < 0.05) with June temperature (r = 0.40) and prior summer CMI (r = 0.40) from 1938 to 2007. An unexplained multi-decadal (i.e., low-frequency) decline in annual basal area increment (BAI) occurred following the mid-20th century, but over the NDVI record there was no trend in mean BAI (P > 0.05), which significantly correlated with NDVIs (r = 0.44, P < 0.05, 1982-2007). Both satellite and tree-ring analyses indicated that plant growth was constrained by both low temperatures and limited moisture availability and, furthermore, that warming enhanced growth. Impacts of future climatic change on forests near treeline in Arctic Russia will likely be influenced by shifts in both temperature and moisture, which implies

  10. A direct test of nitrogen and phosphorus limitation to net primary productivity in a lowland tropical wet forest.

    PubMed

    Alvarez-Clare, S; Mack, M C; Brooks, M

    2013-07-01

    Experimental evidence for limitation of net primary productivity (NPP) by nitrogen (N) or phosphorus (P) in lowland tropical forests is rare, and the results from the few existing studies have been inconclusive. To directly test if N or P limit NPP in a lowland tropical wet forest in Costa Rica, we conducted a full factorial fertilization experiment (4 treatments x 6 replicates in 30 x 30 m plots). We focused on the influence of tree size and taxa on nutrient limitation, because in these forests a wide variety of tree functional traits related to nutrient acquisition and use are likely to regulate biogeochemical processes. After 2.7 years, a higher percentage of trees per plot increased basal area (BA) with P additions (66.45% +/- 3.28% without P vs. 76.88% +/- 3.28% with P), but there were no other community-level responses to N or P additions on BA increase, litterfall productivity, or root growth. Phosphorus additions resulted in doubled stem growth rates in small trees (5-10 cm diameter at breast height (dbh); [P < or = 0.01]) but had no effect on intermediate (10-30 cm dbh) or large trees (> 30 cm dbh). Phosphorus additions also increased the percentage of seedling survival from 59% to 78% (P < 0.01), as well as the percentage of seedlings that grew (P = 0.03), and increased leaf number (P = 0.02). Trees from Pentaclethra macroloba, the most abundant species, did not increase growth rates with fertilization (P = 0.40). In contrast, the most abundant palms (Socratea exorrhiza) had more than two times higher stem growth rates with P additions (P = 0.01). Our experiment reiterates that P availability is a significant driver of plant processes in these systems, but highlights the importance of considering different aspects of the plant community when making predictions concerning nutrient limitation. We postulate that in diverse, lowland tropical forests "heterogeneous nutrient limitation" occurs, not only driven by variability in nutrient responses among taxa

  11. Non-Timber Forest Products' Marketing in Nigeria. A Case Study of Osun State

    ERIC Educational Resources Information Center

    Aiyeloja, Adedapo Ayo; Ajewole, Opeyemi Isaac

    2006-01-01

    Research on markets and marketing of some non-timber forest products (NTFPs) was carried out in selected locations of Osun State. The NTFPs considered are chewing sticks such as "Massularia acuminata" and bush meat like "Thryonomys swinderianus", representing both the flora and fauna aspects of NTFPs, respectively. Five Local Government Areas were…

  12. EFFECTS OF ACID RAIN AND GASEOUS POLLUTANTS ON FOREST PRODUCTIVITY: A REGIONAL SCALE APPROACH

    EPA Science Inventory

    Increased industrialization of the eastern U.S. over the past several decades has led to regional scale buildup of atmospheric pollutants and concern over possible losses in forest productivity within this region. This paper describes the rationale, methodology, and some prelimin...

  13. FOREST HARVESTS AND WOOD PRODUCTS: SOURCES AND SINKS OF ATMOSPHERIC CARBON DIOXIDE

    EPA Science Inventory

    Changes in the net carbon(c)sink-source balance related to a country's forest harvesting and use of wood products is an important component in making country-level inventories of greenhouse gas emissions,a current activity within many signatory nations to the UN Framework Convent...

  14. A Forest Products Technology Program for Washington Community Colleges. Final Report.

    ERIC Educational Resources Information Center

    Grotefend, Robert T.

    This report describes a project to develop a forest product technology curriculum that prepares students at the technical level, junior management, to work in the manufacturing of wood and bark into lumber, plywood, particle board, laminates, and pulp chips. Chapter 1 describes project objectives and procedures followed. In chapter 2 the history…

  15. Post-glacial redistribution and shifts in productivity of giant kelp forests

    PubMed Central

    Graham, Michael H.; Kinlan, Brian P.; Grosberg, Richard K.

    2010-01-01

    Quaternary glacial–interglacial cycles create lasting biogeographic, demographic and genetic effects on ecosystems, yet the ecological effects of ice ages on benthic marine communities are unknown. We analysed long-term datasets to develop a niche-based model of southern Californian giant kelp (Macrocystis pyrifera) forest distribution as a function of oceanography and geomorphology, and synthesized palaeo-oceanographic records to show that late Quaternary climate change probably drove high millennial variability in the distribution and productivity of this foundation species. Our predictions suggest that kelp forest biomass increased up to threefold from the glacial maximum to the mid-Holocene, then rapidly declined by 40–70 per cent to present levels. The peak in kelp forest productivity would have coincided with the earliest coastal archaeological sites in the New World. Similar late Quaternary changes in kelp forest distribution and productivity probably occurred in coastal upwelling systems along active continental margins worldwide, which would have resulted in complex shifts in the relative productivity of terrestrial and marine components of coastal ecosystems. PMID:19846450

  16. Skills Conversion Project: Chapter 6, Forest Operations and Wood Products. Final Report.

    ERIC Educational Resources Information Center

    National Society of Professional Engineers, Washington, DC.

    A study of the forest operations and wood products industries was conducted in Atlanta and Seattle by the National Society of Professional Engineers. Included among these industries are tree development, crop and land management, logging, material handling transportation, cutting, peeling, assembly, pulp and paper, mobile homes, construction,…

  17. PREFER: a European service providing forest fire management support products

    NASA Astrophysics Data System (ADS)

    Eftychidis, George; Laneve, Giovanni; Ferrucci, Fabrizio; Sebastian Lopez, Ana; Lourenco, Louciano; Clandillon, Stephen; Tampellini, Lucia; Hirn, Barbara; Diagourtas, Dimitris; Leventakis, George

    2015-06-01

    PREFER is a Copernicus project of the EC-FP7 program which aims developing spatial information products that may support fire prevention and burned areas restoration decisions and establish a relevant web-based regional service for making these products available to fire management stakeholders. The service focuses to the Mediterranean region, where fire risk is high and damages from wildfires are quite important, and develop its products for pilot areas located in Spain, Portugal, Italy, France and Greece. PREFER aims to allow fire managers to have access to online resources, which shall facilitate fire prevention measures, fire hazard and risk assessment, estimation of fire impact and damages caused by wildfire as well as support monitoring of post-fire regeneration and vegetation recovery. It makes use of a variety of products delivered by space borne sensors and develop seasonal and daily products using multi-payload, multi-scale and multi-temporal analysis of EO data. The PREFER Service portfolio consists of two main suite of products. The first refers to mapping products for supporting decisions concerning the Preparedness/Prevention Phase (ISP Service). The service delivers Fuel, Hazard and Fire risk maps for this purpose. Furthermore the PREFER portfolio includes Post-fire vegetation recovery, burn scar maps, damage severity and 3D fire damage assessment products in order to support relative assessments required in context of the Recovery/Reconstruction Phase (ISR Service) of fire management.

  18. Recent Tree-growth Responses to Warming Vary by Geographic Region and Ecosystem Type within the Boreal Forest-tundra Transition Zone in Alaska

    NASA Astrophysics Data System (ADS)

    Sherriff, R.; Miller, A. E.

    2015-12-01

    A critical concern for boreal ecosystems centers on broad-scale responses to warming; i.e., where warming will lead to declining growth and mortality, or enhanced growth and greater productivity. However, few studies have synthesized tree growth along biogeographic gradients in an attempt to address this issue. We sought to develop a broader understanding of how trees have responded to recent warming for a dominant conifer species from the southern boreal to the western forest margin, an area expected to show signs of an early-stage boreal biome shift. A new 30-site network of ring-width chronologies (1216 trees >4cm dbh) were evaluated for growth differences in Picea glauca across low-elevation, closed forests, open woodlands, and altitudinal treeline from southern interior boreal forest to the western forest-tundra margin. Regional temperature records were used to evaluate 1) whether tree growth near western treeline, which experiences cooler summers but warmer winters than in the interior, showed greater sensitivity to temperature than interior sites, 2) if the temperature-growth response varied through time, across ecosystem types, and by tree age, and 3) if there was a temperature-growth threshold. Positive growth trends since the 1980s in many open stands were consistent with the predicted expansion of western and altitudinal treeline. However, years with temperatures >13oC corresponded with a growth plateau or decline at all but the altitudinal treeline sites regardless of geographic location. Closed-canopy stands showed growth declines, high spruce beetle activity, and less resiliency to further warming. Warming leads to markedly different responses according to ecosystem type and biogeographical setting at the boreal forest-tundra margin. Low-elevation forests are less resilient to further warming where temperatures have already reached threshold levels and further spruce beetle outbreaks occur, even at the western margin of boreal forest.

  19. Influence of spring and autumn phenological transitions on forest ecosystem productivity

    PubMed Central

    Richardson, Andrew D.; Andy Black, T.; Ciais, Philippe; Delbart, Nicolas; Friedl, Mark A.; Gobron, Nadine; Hollinger, David Y.; Kutsch, Werner L.; Longdoz, Bernard; Luyssaert, Sebastiaan; Migliavacca, Mirco; Montagnani, Leonardo; William Munger, J.; Moors, Eddy; Piao, Shilong; Rebmann, Corinna; Reichstein, Markus; Saigusa, Nobuko; Tomelleri, Enrico; Vargas, Rodrigo; Varlagin, Andrej

    2010-01-01

    We use eddy covariance measurements of net ecosystem productivity (NEP) from 21 FLUXNET sites (153 site-years of data) to investigate relationships between phenology and productivity (in terms of both NEP and gross ecosystem photosynthesis, GEP) in temperate and boreal forests. Results are used to evaluate the plausibility of four different conceptual models. Phenological indicators were derived from the eddy covariance time series, and from remote sensing and models. We examine spatial patterns (across sites) and temporal patterns (across years); an important conclusion is that it is likely that neither of these accurately represents how productivity will respond to future phenological shifts resulting from ongoing climate change. In spring and autumn, increased GEP resulting from an ‘extra’ day tends to be offset by concurrent, but smaller, increases in ecosystem respiration, and thus the effect on NEP is still positive. Spring productivity anomalies appear to have carry-over effects that translate to productivity anomalies in the following autumn, but it is not clear that these result directly from phenological anomalies. Finally, the productivity of evergreen needleleaf forests is less sensitive to phenology than is productivity of deciduous broadleaf forests. This has implications for how climate change may drive shifts in competition within mixed-species stands. PMID:20819815

  20. [Carbon dynamics of broad-leaved Korean pine forest ecosystem in Changbai Mountains and its responses to climate change].

    PubMed

    Tang, Feng-De; Han, Shi-Jie; Zhang, Jun-Hui

    2009-06-01

    By using process model Sim-CYCLE based on dry matter production theory, this paper estimated the gross primary productivity (GPP), net primary productivity (NPP), net ecosystem productivity (NEP), ecosystem carbon storage (WE), total plant carbon storage (WP), and total soil carbon storage (WS) of broad-leaved Korean pine forest ecosystem in Changbai Mountains from 1982 to 2003, and analyzed the variations of these indices under present climate condition and carbon equilibrium state as well as the responses of these indices to climate change scenarios in the future. Under present climate condition, the estimated GPP, NPP, and NEP were 14.9, 8.7, and 2.7 Mg C x hm(-2) x a(-1), being 2.8 Mg C x hm(-2) x a(-1) less and 1.4 and 0.2 Mg C x hm(-2) x a(-1) higher than the measured values, respectively. The NEP in June-August occupied more than 90% of the annual NEP, and the maximum monthly NEP appeared in July (1.23 Mg C x hm(-2) month(-1)). The estimated WE, WP, and WS were 550.8, 183.8, and 367.0 Mg C x hm(-2), respectively, very close to the measured values. From present climate condition to carbon equilibrium state, the estimated carbon storages of the forest ecosystem increased to some extent, with the GPP and NPP being 17.7 and 7.3 Mg C x hm(-2) x a(-1), respectively, suggesting that the role of the forest ecosystem as a carbon "sink" declined gradually with the increase of carbon storage. A 2 degree C-increment of air temperature did not benefit the increase of GPP, NPP and NEP, while doubling CO2 concentration was in adverse. The effects of the combination of doubling CO2 concentration and 2 degree C-increment of air temperature on the GPP, NPP, and NEP were similar to those of doubling CO2 concentration. The climate change scenario in the future had the same effects both on the carbon storage and on the productivity of the forest ecosystem, which was mainly correlated to the effects of primary productivity on the carbon storage. PMID:19795634

  1. Climate controls on forest productivity along the climate gradient of the western Sierra Nevada

    NASA Astrophysics Data System (ADS)

    Kelly, A. E.; Goulden, M. L.

    2010-12-01

    The broad climate gradient of the slopes of the western Sierra Nevada mountains supports ecosystems spanning extremes of productivity, biomass, and function. We are using this natural environmental gradient to understand how climate controls NPP, aboveground biomass, species' range limits, and phenology. Our experimental approach combines eddy covariance, sap flow, dendrometer, and litterfall measurements in combination with soil and hydrological data from the Southern Sierra Critical Zone Observatory (SSCZO). We have found that above about 2500 m, forest productivity is limited by winter cold, while below 1200 m, productivity is likely limited by summer drought. The sweet spot between these elevations has a nearly year-long growing season despite a snowpack that persists for as long as six months. Our results show that small differences in temperature can markedly alter the water balance and productivity of mixed conifer forests.

  2. Trace gas responses of tropical forest and pasture soils to N and P fertilization

    NASA Astrophysics Data System (ADS)

    Steudler, Paul A.; Garcia-Montiel, Diana C.; Piccolo, Marisa C.; Neill, Christopher; Melillo, Jerry M.; Feigl, Brigitte J.; Cerri, Carlos C.

    2002-05-01

    We measured the responses of nitric oxide (NO), nitrous oxide (N2O) and carbon dioxide (CO2) to nitrogen (N) and/or phosphorus (P) fertilization in a mature moist tropical forest and an 11-year-old pasture in the Brazilian Amazon. Nitrogen was applied in two forms, ammonium (NH4+) and nitrate (NO3-). In the forest, NO emissions increased by 4 to 9 times the controls in the NH4+ amended plots. Nitrous oxide emissions showed a small response only in the NH4+ amended plots. In the pasture, NO emissions during the first 7 days after fertilization with either form of N were about twice those in the control plots. Nitrous oxide emissions increased more than 18 times the controls in the NO3- amended plots 1 day after fertilization. The estimated yields of total nitrogen oxide loss from the forest were between 0.2 and 1.6% of the applied nitrogen, predominately as NO. Pasture yields were greater, up to 2.8% of the applied nitrogen, predominately as N2O. In the context of Rondônia and other regions in the Amazon Basin, pasture management practices are changing to include increased use of fertilizer, particularly in older pastures that have lower NO and N2O emissions than the original intact forests. This may lead to large short-term releases of N2O and alter the future N2O emissions from the Basin.

  3. Trace gas responses of tropical forest and pasture soils to N and P fertilization

    NASA Astrophysics Data System (ADS)

    Steudler, Paul A.; Garcia-Montiel, Diana C.; Piccolo, Marisa C.; Neill, Christopher; Melillo, Jerry M.; Feigl, Brigitte J.; Cerri, Carlos C.

    2002-06-01

    We measured the responses of nitric oxide (NO), nitrous oxide (N2O) and carbon dioxide (CO2) to nitrogen (N) and/or phosphorus (P) fertilization in a mature moist tropical forest and an 11-year-old pasture in the Brazilian Amazon. Nitrogen was applied in two forms, ammonium (NH4+) and nitrate (NO3-). In the forest, NO emissions increased by 4 to 9 times the controls in the NH4+ amended plots. Nitrous oxide emissions showed a small response only in the NH4+ amended plots. In the pasture, NO emissions during the first 7 days after fertilization with either form of N were about twice those in the control plots. Nitrous oxide emissions increased more than 18 times the controls in the NO3- amended plots 1 day after fertilization. The estimated yields of total nitrogen oxide loss from the forest were between 0.2 and 1.6% of the applied nitrogen, predominately as NO. Pasture yields were greater, up to 2.8% of the applied nitrogen, predominately as N2O. In the context of Rondônia and other regions in the Amazon Basin, pasture management practices are changing to include increased use of fertilizer, particularly in older pastures that have lower NO and N2O emissions than the original intact forests. This may lead to large short-term releases of N2O and alter the future N2O emissions from the Basin.

  4. Changes in hardwood forest understory plant communities in response to European earthworm invasions.

    PubMed

    Hale, Cindy M; Frelich, Lee E; Reich, Peter B

    2006-07-01

    European earthworms are colonizing earthworm-free northern hardwood forests across North America. Leading edges of earthworm invasion provide an opportunity to investigate the response of understory plant communities to earthworm invasion and whether the species composition of the earthworm community influences that response. Four sugar maple-dominated forest sites with active earthworm invasions were identified in the Chippewa National Forest in north central Minnesota, USA. In each site, we established a 30 x 150 m sample grid that spanned a visible leading edge of earthworm invasion and sampled earthworm populations and understory vegetation over four years. Across leading edges of earthworm invasion, increasing total earthworm biomass was associated with decreasing diversity and abundance of herbaceous plants in two of four study sites, and the abundance and density of tree seedlings decreased in three of four study sites. Sample points with the most diverse earthworm species assemblage, independent of biomass, had the lowest plant diversity. Changes in understory plant community composition were most affected by increasing biomass of the earthworm species Lumbricus rubellus. Where L. rubellus was absent there was a diverse community of native herbaceous plants, but where L. rubellus biomass reached its maximum, the herbaceous-plant community was dominated by Carex pensylvanica and Arisaema triphyllum and, in some cases, was completely absent. Evidence from these forest sites suggests that earthworm invasion can lead to dramatic changes in the understory community and that the nature of these changes is influenced by the species composition of the invading earthworm community. PMID:16922315

  5. Analysis of Individual Variations in Autonomic Responses to Urban and Forest Environments

    PubMed Central

    Kobayashi, Hiromitsu; Song, Chorong; Ikei, Harumi; Kagawa, Takahide; Miyazaki, Yoshifumi

    2015-01-01

    Autonomic responses to urban and forest environments were studied in 625 young male subjects. The experimental sites were 57 forests and 57 urban areas across Japan. The subjects viewed the landscape (forest or urban environment) for a period of 15 min while sitting on a chair. During this period, heart rate variability (HRV) was monitored continuously. The results were presented as histograms and analyzed with special reference to individual variations. Approximately 80% of the subjects showed an increase in the parasympathetic indicator of HRV (lnHF), whereas the remaining subjects showed a decrease in the parasympathetic activity. Similarly, 64.0% of the subjects exhibited decreases in the sympathetic indicator of HRV (ln[LF/HF]), whereas the remaining subjects showed opposite responses. Analysis of the distribution of HRV indices (lnHF and ln[LF/HF]) demonstrated the effect of forest environments on autonomic activity more specifically than the conventional analysis based on the difference in mean values. PMID:26508983

  6. A multi-sites analysis on the ozone effects on Gross Primary Production of European forests.

    PubMed

    Proietti, C; Anav, A; De Marco, A; Sicard, P; Vitale, M

    2016-06-15

    Ozone (O3) is both a greenhouse gas and a secondary air pollutant causing adverse impacts on forests ecosystems at different scales, from cellular to ecosystem level. Specifically, the phytotoxic nature of O3 can impair CO2 assimilation that, in turn affects forest productivity. This study aims to evaluate the effects of tropospheric O3 on Gross Primary Production (GPP) at 37 European forest sites during the time period 2000-2010. Due to the lack of carbon assimilation data at O3 monitoring stations (and vice-versa) this study makes a first attempt to combine high resolution MODIS Gross Primary Production (GPP) estimates and O3 measurement data. Partial Correlations, Anomalies Analysis and the Random Forests Analysis (RFA) were used to quantify the effects of tropospheric O3 concentration and its uptake on GPP and to evaluate the most important factors affecting inter-annual GPP changes. Our results showed, along a North-West/South-East European transect, a negative impact of O3 on GPP ranging from 0.4% to 30%, although a key role of meteorological parameters respect to pollutant variables in affecting GPP was found. In particular, meteorological parameters, namely air temperature (T), soil water content (SWC) and relative humidity (RH) are the most important predictors at 81% of test sites. Moreover, it is interesting to highlight a key role of SWC in the Mediterranean areas (Spanish, Italian and French test sites) confirming that, soil moisture and soil water availability affect vegetation growth and photosynthesis especially in arid or semi-arid ecosystems such as the Mediterranean climate regions. Considering the pivotal role of GPP in the global carbon balance and the O3 ability to reduce primary productivity of the forests, this study can help in assessing the O3 impacts on ecosystem services, including wood production and carbon sequestration. PMID:26971205

  7. 77 FR 65095 - National Forest Products Week, 2012

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-24

    ... growth in our rural communities. They provide the raw materials for products we use every day, and they... Independence of the United States of America the two hundred and thirty-seventh. (Presidential Sig.) [FR...

  8. Causes and implications of the correlation between forest productivity and tree mortality rates

    USGS Publications Warehouse

    Stephenson, Nathan L.; van Mantgem, Philip J.; Bunn, Andrew G.; Bruner, Howard; Harmon, Mark E.; O'Connell, Kari B.; Urban, Dean L.; Franklin, Jerry F.

    2011-01-01

    For only one of these four mechanisms, competition, can high mortality rates be considered to be a relatively direct consequence of high NPP. The remaining mechanisms force us to adopt a different view of causality, in which tree growth rates and probability of mortality can vary with at least a degree of independence along productivity gradients. In many cases, rather than being a direct cause of high mortality rates, NPP may remain high in spite of high mortality rates. The independent influence of plant enemies and other factors helps explain why forest biomass can show little correlation, or even negative correlation, with forest NPP.

  9. Disturbance severity and net primary production resilience of a Great Lakes forest ecosystem

    NASA Astrophysics Data System (ADS)

    Goodrich-Stuart, E. J.; Fahey, R.; De La Cruz, A.; Gough, C. M.

    2013-12-01

    As many Eastern deciduous forests of North America transition from early to mid-succession, the future of regional terrestrial carbon (C) storage is uncertain. The gradual, patchy senescence of early-successional trees accompanying this transition is comparable in severity to moderate disturbances such as silvicultural thinnings or insect outbreaks. While stand-replacing disturbance causes forests to temporarily become C sources, more moderate disturbances may inflict little to no decline in C sequestration. Identifying the disturbance severity at which net primary production (NPP) declines and the underlying mechanisms that drive forest C storage resistance to disturbance is increasingly important as moderate disturbances increase in frequency and extent across the region. The Forest Accelerated Succession ExperimenT (FASET) at the University of Michigan Biological Station subjected 39 ha of forest to moderate disturbance in 2008 by advancing age-related tree mortality through the stem girdling of early successional aspen and birch. Stand-scale disturbance severity, expressed as relative basal area of girdled aspen and birch, was 39% but plot-scale severity varied substantially within the experimental area (9 to 66% in 0.1 ha plots) because of the heterogeneous distribution of aspen and birch. We used this disturbance severity gradient to examine: 1) the relationship between NPP resilience and disturbance severity; 2) the disturbance severity at which NPP resilience prompts a shift in dominance from canopy to subcanopy vegetation; 3) how NPP resilience relates to disturbance-driven changes in resource-use efficiency, and 4) how disturbance severity shapes emerging forest communities We found that NPP is highly resilient to low to moderate levels of disturbance, but that production declines once a higher disturbance threshold is exceeded. Several complementary mechanisms, including canopy structural reorganization and the reallocation of growth-limiting light and

  10. Modeling climate change effects on the potential production of French plains forests at the sub-regional level.

    PubMed

    Loustau, Denis; Bosc, Alexandre; Colin, Antoine; Ogée, Jérôme; Davi, Hendrik; François, Christophe; Dufrêne, Eric; Déqué, Michel; Cloppet, Emmanuel; Arrouays, Dominique; Le Bas, Christine; Saby, Nicolas; Pignard, Gérôme; Hamza, Nabila; Granier, André; Bréda, Nathalie; Ciais, Philippe; Viovy, Nicolas; Delage, François

    2005-07-01

    We modeled the effects of climate change and two forest management scenarios on wood production and forest carbon balance in French forests using process-based models of forest growth. We combined data from the national forest inventory and soil network survey, which were aggregated over a 50 x 50-km grid, i.e., the spatial resolution of the climate scenario data. We predicted and analyzed the climate impact on potential forest production over the period 1960-2100. All models predicted a slight increase in potential forest yield until 2030-2050, followed by a plateau or a decline around 2070-2100, with overall, a greater increase in yield in northern France than in the south. Gross and net primary productivities were more negatively affected by soil water and atmospheric water vapor saturation deficits in western France because of a more pronounced shift in seasonal rainfall from summer to winter. The rotation-averaged values of carbon flux and production for different forest management options were estimated during four years (1980, 2015, 2045 and 2080). Predictions were made using a two-dimensional matrix covering the range of local soil and climate conditions. The changes in ecosystem fluxes and forest production were explained by the counterbalancing effect of rising CO2 concentration and increasing water deficit. The effect of climate change decreased with rotation length from short rotations with high production rates and low standing biomasses to long rotations with low productivities and greater standing biomasses. Climate effects on productivity, both negative and positive, were greatest on high fertility sites. Forest productivity in northern France was enhanced by climate change, increasingly from west to east, whereas in the southwestern Atlantic region, productivity was reduced by climate change to an increasing degree from west to east. PMID:15870051

  11. Extended Producer Responsibility and Product Stewardship for Tobacco Product Waste

    PubMed Central

    Curtis, Clifton; Collins, Susan; Cunningham, Shea; Stigler, Paula; Novotny, Thomas E

    2015-01-01

    This paper reviews several environmental principles, including Extended Producer Responsibility (EPR), Product Stewardship (PS), the Polluter Pays Principle (PPP), and the Precautionary Principle, as they may apply to tobacco product waste (TPW). The review addresses specific criteria that apply in deciding whether a particular toxic product should adhere to these principles; presents three case studies of similar approaches to other toxic and/or environmentally harmful products; and describes 10 possible interventions or policy actions that may help prevent, reduce, and mitigate the effects of TPW. EPR promotes total lifecycle environmental improvements, placing economic, physical, and informational responsibilities onto the tobacco industry, while PS complements EPR, but with responsibility shared by all parties involved in the tobacco product lifecycle. Both principles focus on toxic source reduction, post-consumer take-back, and final disposal of consumer products. These principles when applied to TPW have the potential to substantially decrease the environmental and public health harms of cigarette butts and other TPW throughout the world. TPW is the most commonly littered item picked up during environmental, urban, and coastal cleanups globally. PMID:26457262

  12. Change of outlook for the forest productivity estimated with remote sensing using the new Collection 6 GPP/NPP MODIS product

    NASA Astrophysics Data System (ADS)

    Marjanović, Hrvoje; Kern, Anikó; Anić, Mislav; Zorana Ostrogović Sever, Maša; Balenović, Ivan; Alberti, Giorgio; Kovač, Goran; Barcza, Zoltán

    2016-04-01

    Estimates of forest productivity from remote sensing data, such as the MOD17 GPP and NPP values derived from MODIS data, are becoming increasingly important tools for monitoring forest productivity in light of the climate change. Hence, small sensor degradation, like the one in the case of MODIS sensor on-board satellite Terra could lead so significant bias in results and false conclusions of the path that the ecosystem is on. In new Collection 6 (C6) of the MOD17 product, the sensor degradation problem has been addressed compared to the previous version Collection 5.5 (C5.5) products, offering a new outlook on the trends in forest productivity. In our work we compared the C5.5 and C6 for MOD17 GPP and NPP products against estimates from eddy covariance and field measurements ('ground truth') at young Pedunculate oak site in Jastrebarsko forest. In order to assess the outlook of forest productivity at larger scale we intersected in GIS maps of forest areas under management and MODIS pixels with 1km spatial resolution. After selecting only those pixels that have at least 90% forest coverage according to the management plans, we analysed the temporal trends and variability in MODIS derived GPP and NPP both from C5.5 and C6 products. Analysis was performed for four main forests classes according to the dominant tree species (Pedunculate oak, Sessile oak, Common beech and Silver fir).

  13. The effects of partial throughfall exclusion on canopy processes, aboveground production, and biogeochemistry of an Amazon forest

    NASA Astrophysics Data System (ADS)

    Nepstad, D. C.; Moutinho, P.; Dias-Filho, M. B.; Davidson, E.; Cardinot, G.; Markewitz, D.; Figueiredo, R.; Vianna, N.; Chambers, J.; Ray, D.; Guerreiros, J. B.; Lefebvre, P.; Sternberg, L.; Moreira, M.; Barros, L.; Ishida, F. Y.; Tohlver, I.; Belk, E.; Kalif, K.; Schwalbe, K.

    2002-10-01

    Moist tropical forests in Amazonia and elsewhere are subjected to increasingly severe drought episodes through the El Niño-Southern Oscillation (ENSO) and possibly through deforestation-driven reductions in rainfall. The effects of this trend on tropical forest canopy dynamics, emissions of greenhouse gases, and other ecological functions are potentially large but poorly understood. We established a throughfall exclusion experiment in an east-central Amazon forest (Tapajós National Forest, Brazil) to help understand these effects. After 1-year intercalibration period of two 1-ha forest plots, we installed plastic panels and wooden gutters in the understory of one of the plots, thereby excluding ˜890 mm of throughfall during the exclusion period of 2000 (late January to early August) and ˜680 mm thus far in the exclusion period of 2001 (early January to late May). Average daily throughfall reaching the soil during the exclusion period in 2000 was 4.9 and 8.3 mm in the treatment and control plots and was 4.8 and 8.1 mm in 2001, respectively. During the first exclusion period, surface soil water content (0-2 m) declined by ˜100 mm, while deep soil water (2-11 m) was unaffected. During the second exclusion period, which began shortly after the dry season when soil water content was low, surface and deep soil water content declined by ˜140 and 160 mm, respectively. Although this depletion of soil water provoked no detectable increase in leaf drought stress (i.e., no reduction in predawn leaf water potential), photosynthetic capacity declined for some species, the canopy thinned (greater canopy openness and lower leaf area index) during the second exclusion period, stem radial growth of trees <15 m tall declined, and fine litterfall declined in the treatment plot, as did tree fruiting. Aboveground net primary productivity (NPP) (stemwood increment and fine litter production) declined by one fourth, from 15.1 to 11.4 Mg ha-1 yr-1, in the treatment plot and decreased

  14. Sustaining the Productivity and Function of Intensively Managed Forests - Final Report

    SciTech Connect

    Burger, James A.; Xu, Yi-Jun

    2001-03-23

    The main goal of this study is to ensure sustainable management of wetland forests in the southeastern United States. The study is projected to measure soil, hydrology, and forest responses to several management scenarios across a complete forest cycle. From August 1997 to August 2000 the study has received funding as one of the Agenda 2020 projects, from the U.S. Department of Energy (Cooperative Agreement Number DE-FC07-97ID13551), the National Council of the Paper Industry for Air and Stream Improvement, and Westvac Corporation. Quarterly progress reports were submitted regularly to the Department and all project participants. This final report summarizes the project results and progress achieved during this 3-year period. Over the past three years all research objectives planned for this project were completed.

  15. Limitation of Biofuel Production in Europe from the Forest Market

    NASA Astrophysics Data System (ADS)

    Leduc, Sylvain; Wetterlund, Elisabeth; Dotzauer, Erik; Kindermann, Georg

    2013-04-01

    The European Union has set a 10% target for the share of biofuel in the transportation sector to be met by 2020. To reach this target, second generation biofuel is expected to replace 3 to 5% of the transport fossil fuel consumption. But the competition on the feedstock is an issue and makes the planning for the second generation biofuel plant a challenge. Moreover, no commercial second generation biofuel production plant is under operation, but if reaching commercial status, this type of production plants are expected to become very large. In order to minimize the tranportation costs and to takle the competetion for the feedstock against the existing woody based industries, the geographical location of biofuel production plants becomes an issue. This study investigates the potential of second generation biofuel economically feasible in Europe by 2020 in regards with the competition for the feedsstock with the existing woody biomass based industries (CHP, pulp and paper mills, sawmills...). To assess the biofuel potential in Europe, a techno-economic, geographically explicit model, BeWhere, is used. It determines the optimal locations of bio-energy production plants by minimizing the costs and CO2 emissions of the entire supply chain. The existing woody based industries have to first meet their wood demand, and if the amount of wood that remains is suficiant, new bio-energy production plants if any can be set up. Preliminary results show that CHP plants are preferably chosen over biofuel production plants. Strong biofuel policy support is needed in order to consequently increase the biofuel production in Europe. The carbon tax influences the emission reduction to a higher degree than the biofuel support. And the potential of second generation biofuel would at most reach 3% of the European transport fuel if the wood demand does not increase from 2010.

  16. Short-term precipitation exclusion alters microbial responses to soil moisture in a wet tropical forest.

    PubMed

    Waring, Bonnie G; Hawkes, Christine V

    2015-05-01

    Many wet tropical forests, which contain a quarter of global terrestrial biomass carbon stocks, will experience changes in precipitation regime over the next century. Soil microbial responses to altered rainfall are likely to be an important feedback on ecosystem carbon cycling, but the ecological mechanisms underpinning these responses are poorly understood. We examined how reduced rainfall affected soil microbial abundance, activity, and community composition using a 6-month precipitation exclusion experiment at La Selva Biological Station, Costa Rica. Thereafter, we addressed the persistent effects of field moisture treatments by exposing soils to a controlled soil moisture gradient in the lab for 4 weeks. In the field, compositional and functional responses to reduced rainfall were dependent on initial conditions, consistent with a large degree of spatial heterogeneity in tropical forests. However, the precipitation manipulation significantly altered microbial functional responses to soil moisture. Communities with prior drought exposure exhibited higher respiration rates per unit microbial biomass under all conditions and respired significantly more CO2 than control soils at low soil moisture. These functional patterns suggest that changes in microbial physiology may drive positive feedbacks to rising atmospheric CO2 concentrations if wet tropical forests experience longer or more intense dry seasons in the future. PMID:24889286

  17. Trajectories of Disturbance in Island SE Asia: A Hypothesis of Anthropogenic Forest Management and Food Production

    NASA Astrophysics Data System (ADS)

    Hunt, C. O.

    2014-12-01

    This paper synthesises evidence from Late Quaternary pollen diagrams from across Island SE Asia to show that what appears to be anthopogenic forest modification started more than 50,000 years ago. Initially disturbance of forests was by fire, during interstadials when successional processes would otherwise have led to closed canopy forest. It is hypothesised that the resultant habitats would have provided accessible broad-spectrum resources to mobile foraging populations. During the Holocene, there is some evidence for the early interchange and propagation of economically-important plants, notably between New Guinea and Borneo. I use GIS to chart patterns of floral disturbance through the Holocene, most probably linked to diverse land management and food production strategies. We need a new wave of pollen and charcoal-based studies plus plant macrofossil work on many archaeological sites across the region to test and substantiate this hypothesis.

  18. Biophysical, morphological, canopy optical property, and productivity data from the Superior National Forest

    NASA Technical Reports Server (NTRS)

    Hall, F. G.; Huemmrich, K. F.; Strebel, D. E.; Goetz, S. J.; Nickeson, J. E.; Woods, K. D.

    1992-01-01

    Described here are the results of a NASA field experiment conducted in the Superior National Forest near Ely, Minnesota, during the summers of 1983 and 1984. The purpose of the experiment was to examine the use of remote sensing to provide measurements of biophysical parameters in the boreal forests. Leaf area index, biomass, net primary productivity, canopy coverage, overstory and understory species composition data are reported for about 60 sites, representing a range of stand density and age for aspen and spruce. Leaf, needle, and bark high-resolution spectral reflectance and transmittance data are reported for the major boreal forest species. Canopy bidirectional reflectance measurements are provided from a helicopter-mounted Barnes Multiband Modular Radiometer (MMR) and the Thematic Mapper Simulator (TMS) on the NASA C-130 aircraft.

  19. Seasonal and successional streamflow response to forest cutting and regrowth in the northwest and eastern United States

    NASA Astrophysics Data System (ADS)

    Jones, Julia A.; Post, David A.

    2004-05-01

    This study examined daily streamflow response over up to four decades in northwest conifer forest and eastern deciduous forest sites in the United States. We used novel methods to analyze daily observations of climate and streamflow spanning more than 900 basin years of record at 14 treated/control basin pairs where forest removal and regrowth experiments were underway in the period 1930-2002. In the 1 to 5-year period after forest removal, maximum daily increases ranged from 2 to 3 mm at deciduous forest sites, to 6 to 8 mm at conifer forest sites. Significant spring surpluses persisted for up to 35 years in conifer forest basins, but winter and spring streamflow deficits appeared after 10 to 15 years of forest regrowth in eastern deciduous forest basins. In all 5-yr posttreatment periods, absolute changes in daily streamflow were significantly more likely during moist, warm seasons, or during snowmelt seasons, but relative changes were more likely during warm seasons irrespective of moisture status. Both relative and absolute streamflow changes in the 1 to 5 and 15 to 25-year periods after forest removal were significantly positively related to the age of the forest at the time it was cut. Eastern deciduous forests had been disturbed by logging or hurricane 12 to 56 years prior to forest removal, while Pacific Northwest conifer forests had been not experienced logging or wildfire for 90 to 450 years. Paired basin experiments provide a continuous, and continuously changing, record of vegetation structure, composition, and climate, and their effects on streamflow.

  20. Response of a forest ecotone to ionizing radiation. Progress report, October 15, 1980-October 14, 1981

    SciTech Connect

    Murphy, P.G.; Sharitz, R.R.

    1981-06-01

    The primary objectives of this study are to determine the effects of ionizing radiation on the tree species composition of the ecotone between two forest types in northern Wisconsin and to compare the postirradiation recovery of the tree flora in the ecotone with that in the bordering forest types. Relatively distinct ecotones constitute a spatially significant portion of many second-growth forest ecosystems. Belt transects concentric to the radiation source (/sup 137/Cs) are being used to measure compositional changes in the ecotone from aspen to maple-birch forest types. Information available includes population densities by size class, importance values, and diversity values. Estimates of leaf area index and leaf litter production, by species, have also been obtained. Succession in the radiation areas is presently under study. To date, redevelopment of forest vegetation at up to 20 m from the radiation source has been slowed significantly by the vigorous colonization of heliophytes. Sampling for 1980-81 is on schedule. In all three areas competition from successional ground vegetation has continued to delay re-establishment of tree seedlings under the opened canopy at 10 m. In this regard, only the aspen area has shown any signs of recovering, having experienced an influx of red maple seedlings in 1978. Even that area, however, is still less than half preirradiation levels with respect to seedling densities. As unusually high ratio of shrub leaf litter to tree leaf litter in the 10 to 20 m area reflects the displacement of canopy species by successional shrubs. As the overall impact of the radiation stress depends on the rate of forest re-establishment, observations will continue for several more years.

  1. Mycorrhizal Response to Experimental pH and P Manipulation in Acidic Hardwood Forests

    PubMed Central

    Kluber, Laurel A.; Carrino-Kyker, Sarah R.; Coyle, Kaitlin P.; DeForest, Jared L.; Hewins, Charlotte R.; Shaw, Alanna N.; Smemo, Kurt A.; Burke, David J.

    2012-01-01

    Many temperate forests of the Northeastern United States and Europe have received significant anthropogenic acid and nitrogen (N) deposition over the last century. Although temperate hardwood forests are generally thought to be N-limited, anthropogenic deposition increases the possibility of phosphorus (P) limiting productivity in these forest ecosystems. Moreover, inorganic P availability is largely controlled by soil pH and biogeochemical theory suggests that forests with acidic soils (i.e., forest ecosystems overcome an underlying P limitation by accessing mineral and organic P sources that are otherwise unavailable for direct plant uptake. We examined arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) communities and soil microbial activity in an ecosystem-level experiment where soil pH and P availability were manipulated in mixed deciduous forests across eastern Ohio, USA. One year after treatment initiation, AM root biomass was positively correlated with the most available P pool, resin P, while AM colonization was negatively correlated. In total, 15,876 EcM root tips were identified and assigned to 26 genera and 219 operational taxonomic units (97% similarity). Ectomycorrhizal richness and root tip abundance were negatively correlated with the moderately available P pools, while the relative percent of tips colonized by Ascomycetes was positively correlated with soil pH. Canonical correspondence analysis revealed regional, but not treatment, differences in AM communities, while EcM communities had both treatment and regional differences. Our findings highlight the complex interactions between mycorrhizae and the soil environment and further underscore the fact that mycorrhizal communities do not merely

  2. Interactions between climate change impacts on forest productivity and mortality and stream water quality in the US Western Mountains (Invited)

    NASA Astrophysics Data System (ADS)

    Tague, C.; Zhu, J.

    2013-12-01

    In the snow-dominated mountains of the Western US, climate change is likely to alter forest productivity, water use and nutrient uptake. The consequence of changes in forest structure and function will have impacts on both water quality and water quantity. Warmer temperatures, reduced snow accumulation and earlier melt, elevated CO2 and increased frequency and severity of drought all influence forest productivity, sometimes in opposing ways. In the complex topography of mountain environments, whether forest productivity increases or decreases is likely to vary along gradients between water and energy limited systems. Implications for forest structure also vary along these gradients, and include the impact of disturbances such as fire and pests. We build on earlier work that used a coupled eco-hydrologic model to show how forest water use changes with increasing temperatures and how these changes are distributed along elevational gradients for a snow-dominated site within the California Sierra. We extend this analysis to investigate associated changes in forest structure and nutrient uptake with temperature warming, along an elevational gradient. We compare results for sites in the California Sierra and the wetter Pacific Northwest. Results show that for wetter sites, forest productivity is likely to increases with associated declines in stream nutrient export. For drier sites, however, forest productivity may decline leading to reduced forest nutrient uptake. This decline in uptake is combined with shifts to more winter rainfall that together may facilitate greater flushing of nutrients. We use these results to define scenarios where we would expect forest productivity to decline and lead to increase nitrate leaching to stream and groundwater.

  3. Electrocatalyzed O2 response of myoglobin immobilized on multi-walled carbon nanotube forest electrodes.

    PubMed

    Pacios, M; del Valle, M; Bartroli, J; Esplandiu, M J

    2009-10-01

    Direct electrochemistry and activity of myoglobin (Mb) immobilized on carbon nanotube (CNT) forest electrodes were investigated by probing mainly its electrocatalytical response towards oxygen. The protein was anchored on the CNT electrodes through carbodiimide coupling, which was shown to provide long term stability. The electrochemical response was monitored as a function of oxygen concentration and pH. Conformational changes together with the consequent loss of oxygen affinity were recorded at low pH, which delimits the operative range of the Mb/CNT electrodes for sensing purposes. In general, it can be concluded that CNT forests constitute suitable platforms for Mb attachment without compromising the protein bioactivity and by keeping at the same time the direct electron exchange with the heme core. All these characteristics confer to the protein modified CNT system promising properties for the implementation of (bio)sensor devices with impact in the clinical and environmental field. PMID:19908505

  4. Responses of grassland and forest to temperature and precipitation changes in Northeast China

    NASA Astrophysics Data System (ADS)

    Peng, Jing; Dong, Wenjie; Yuan, Wenping; Zhang, Yong

    2012-09-01

    Using the Normalized Difference Vegetation Index (NDVI) as an indicator of vegetation growth, we explored the characteristics and differences in the response to drought of five vegetation biomes in Northeast China, including typical steppe, desert steppe, meadow steppe, deciduous coniferous forest and deciduous broad-leaved forest during the period 1982-2009. The results indicate that growing season precipitation may be the primary vegetation growth-limiting factor in grasslands. More than 70% of the temporal variations in NDVI can be explained by the amount of precipitation during the growing season in typical and desert steppes. During the same period, the mean temperature in the growing season could explain nearly 43% of the variations in the mean growing season NDVI and is therefore a dominant growth-limiting factor for forest ecosystems. Therefore, the NDVI trends differ largely due to differences in the vegetation growth-limiting factors of the different vegetation biomes. The NDVI responses to droughts vary in magnitude and direction and depend on the drought-affected areas of the five vegetation types. Specifically, the changes in NDVI are consistent with the variations in precipitation for grassland ecosystems. A lack of precipitation resulted in decreases in NDVI, thereby reducing vegetation growth in these regions. Conversely, increasing precipitation decreased the NDVI of forest ecosystems. The results also suggest that grasslands under arid and semi-arid environments may be more sensitive to drought than forests under humid environments. Among grassland ecosystems, desert steppe was most sensitive to drought, followed by typical steppe; meadow steppe was the least sensitive.

  5. Long-Term Effects of Acid Rain: Response and Recovery of a Forest Ecosystem

    NASA Astrophysics Data System (ADS)

    Likens, G. E.; Driscoll, C. T.; Buso, D. C.

    1996-04-01

    Long-term data from the Hubbard Brook Experimental Forest, New Hampshire, suggest that although changes in stream pH have been relatively small, large quantities of calcium and magnesium have been lost from the soil complex and exported by drainage water because of inputs of acid rain and declines in atmospheric deposition of base cations. As a result, the recovery of soil and streamwater chemistry in response to any decreases in acid deposition will be delayed significantly.

  6. Spatially variant lagged responses of forest extent and landscape patterns to socioeconomic drivers in the Li River Basin, China

    NASA Astrophysics Data System (ADS)

    Zhang, Yuan; Li, Jun; Qin, Qiming; Xu, Ruofeng; Lin, Cong

    2016-01-01

    Forest cover change is one of the most important land cover changes. Intensified economic development and population growth have led to extensive deforestation and afforestation, and greatly altered the forest landscape patterns. This paper analyzed how socioeconomic drivers influenced the forest extent and landscape patterns in a lagged manner within the Li River Basin, Guangxi Zhuang Autonomous Region, China, during the period of 1991 to 2013. First, the temporal variations of forest extent and landscape patterns as quantified by six forest cover metrics were analyzed. The cross-correlation analysis was employed to examine the lagged responses of forest cover metrics to each socioeconomic driver across regions. Last, the fixed effects regression models were built to quantitatively assess the spatially variant relationships. The results demonstrated that the influence of socioeconomic drivers lagged, and the lagged influence varied across regions.

  7. Woody biomass production lags stem-girth increase by over one month in coniferous forests.

    PubMed

    Cuny, Henri E; Rathgeber, Cyrille B K; Frank, David; Fonti, Patrick; Mäkinen, Harri; Prislan, Peter; Rossi, Sergio; Del Castillo, Edurne Martinez; Campelo, Filipe; Vavrčík, Hanuš; Camarero, Jesus Julio; Bryukhanova, Marina V; Jyske, Tuula; Gričar, Jožica; Gryc, Vladimír; De Luis, Martin; Vieira, Joana; Čufar, Katarina; Kirdyanov, Alexander V; Oberhuber, Walter; Treml, Vaclav; Huang, Jian-Guo; Li, Xiaoxia; Swidrak, Irene; Deslauriers, Annie; Liang, Eryuan; Nöjd, Pekka; Gruber, Andreas; Nabais, Cristina; Morin, Hubert; Krause, Cornelia; King, Gregory; Fournier, Meriem

    2015-01-01

    Wood is the main terrestrial biotic reservoir for long-term carbon sequestration(1), and its formation in trees consumes around 15% of anthropogenic carbon dioxide emissions each year(2). However, the seasonal dynamics of woody biomass production cannot be quantified from eddy covariance or satellite observations. As such, our understanding of this key carbon cycle component, and its sensitivity to climate, remains limited. Here, we present high-resolution cellular based measurements of wood formation dynamics in three coniferous forest sites in northeastern France, performed over a period of 3 years. We show that stem woody biomass production lags behind stem-girth increase by over 1 month. We also analyse more general phenological observations of xylem tissue formation in Northern Hemisphere forests and find similar time lags in boreal, temperate, subalpine and Mediterranean forests. These time lags question the extension of the equivalence between stem size increase and woody biomass production to intra-annual time scales(3, 4, 5, 6). They also suggest that these two growth processes exhibit differential sensitivities to local environmental conditions. Indeed, in the well-watered French sites the seasonal dynamics of stem-girth increase matched the photoperiod cycle, whereas those of woody biomass production closely followed the seasonal course of temperature. We suggest that forecasted changes in the annual cycle of climatic factors(7) may shift the phase timing of stem size increase and woody biomass production in the future. PMID:27251531

  8. Compartmentalized and contrasted response of ectomycorrhizal and soil fungal communities of Scots pine forests along elevation gradients in France and Spain.

    PubMed

    Rincón, Ana; Santamaría-Pérez, Blanca; Rabasa, Sonia G; Coince, Aurore; Marçais, Benoit; Buée, Marc

    2015-08-01

    Fungi are principal actors of forest soils implied in many ecosystem services and the mediation of tree's responses. Forecasting fungal responses to environmental changes is necessary for maintaining forest productivity, although our partial understanding of how abiotic and biotic factors affect fungal communities is restricting the predictions. We examined fungal communities of Pinus sylvestris along elevation gradients to check potential responses to climate change-associated factors. Fungi of roots and soils were analysed at a regional scale, by using a high-throughput sequencing approach. Overall soil fungal richness increased with pH, whereas it did not vary with climate. However, when representative sub-assemblages, i.e. Ascomycetes/Basidiomycetes, and families were analysed, they differentially answered to climatic and edaphic variables. This response was dependent on where they settled, i.e. soil versus roots, and/or on their lifestyle, i.e. mycorrhizal or not, suggesting different potential functional weights within the community. Our results revealed a highly compartmentalized and contrasted response of fungal communities in forest soils. The different response of fungal sub-assemblages indicated a range of possible selective direct and indirect (i.e. via host) impacts of climatic variations on these communities, of unknown functional consequences, that helps in understanding potential fungal responses under future global change scenarios. PMID:25953485

  9. Forest Owners' Response to Climate Change: University Education Trumps Value Profile

    PubMed Central

    Persson, Erik; Hanewinkel, Marc

    2016-01-01

    Do forest owners’ levels of education or value profiles explain their responses to climate change? The cultural cognition thesis (CCT) has cast serious doubt on the familiar and often criticized "knowledge deficit" model, which says that laypeople are less concerned about climate change because they lack scientific knowledge. Advocates of CCT maintain that citizens with the highest degrees of scientific literacy and numeracy are not the most concerned about climate change. Rather, this is the group in which cultural polarization is greatest, and thus individuals with more limited scientific literacy and numeracy are more concerned about climate change under certain circumstances than those with higher scientific literacy and numeracy. The CCT predicts that cultural and other values will trump the positive effects of education on some forest owners' attitudes to climate change. Here, using survey data collected in 2010 from 766 private forest owners in Sweden and Germany, we provide the first evidence that perceptions of climate change risk are uncorrelated with, or sometimes positively correlated with, education level and can be explained without reference to cultural or other values. We conclude that the recent claim that advanced scientific literacy and numeracy polarizes perceptions of climate change risk is unsupported by the forest owner data. In neither of the two countries was university education found to reduce the perception of risk from climate change. Indeed in most cases university education increased the perception of risk. Even more importantly, the effect of university education was not dependent on the individuals' value profile. PMID:27223473

  10. Projection of response of trees and forests to acidic deposition and associated pollutants

    SciTech Connect

    Kiester, A.R.; Ford, E.D.; Avery, A.; Gay, C.; Droessler, T.

    1990-09-01

    In 1986 the National Acid Precipitation Assessment Program (NAPAP) established the Forest Response Program (FRP) to assess the effects of acidic deposition and associated pollutants on forests. Modeling studies were developed in parallel with both field studies on the pattern and trends of forest condition and physiological studies of seedlings, saplings, and branches of mature trees. The goals of the modeling effort were to simulate the dynamics of the processes by which acidic deposition and ozone affect tree physiological processes and therefore lead to changes in growth. Results from models of the physiological function of leaves, branches, roots, xylem, and canopies are presented here. These models illustrate three aspects of the dynamics of these processes. First, growth and the effects of pollutants are stochastic processes; that is, they vary randomly over time. The models help to account for the large amount of variability seen in normal field conditions. Second, some physiological processes can compensate for the effects of acidic deposition or ozone. Third, pollutants may have more than one effect on tree growth, and these effects may be synergistic. The potential nonlinearities and the variabilities demonstrated by these models lead to the conclusions that forest health effects may be developing that are not yet apparent; and for regulation of acidic deposition and associated pollutants to have a detectable effect, regulatory changes will probably have to be of substantial magnitude.

  11. Effects of morphology on the micro-compression response of carbon nanotube forests.

    PubMed

    Abadi, Parisa Pour Shahid Saeed; Hutchens, Shelby B; Greer, Julia R; Cola, Baratunde A; Graham, Samuel

    2012-06-01

    This study reports the mechanical response of distinct carbon nanotube (CNT) morphologies as revealed by flat punch in situ nanoindentation in a scanning electron microscope. We find that the location of incipient deformation varies significantly by changing the CNT growth parameters. The initial buckles formed close to the growth substrate in 70 and 190 μm tall CNT forests grown with low pressure chemical vapor deposition (LPCVD) and moved to ∼100 μm above the growth substrate when the height increased to 280 μm. Change of the recipe from LPCVD to CVD at pressures near atmospheric changed the location of the initial buckling event from the bottom half to the top half of the CNT forest. Plasma pretreatment of the catalyst also resulted in a unique CNT forest morphology in which deformation started by bending and buckling of the CNT tips. We find that the vertical gradients in CNT morphology dictate the location of incipient buckling. These new insights are critical in the design of CNT forests for a variety of applications where mechanical contact is important. PMID:22543679

  12. Climate response of the soil nitrogen cycle in three forest types of a headwater Mediterranean catchment

    NASA Astrophysics Data System (ADS)

    Lupon, Anna; Gerber, Stefan; Sabater, Francesc; Bernal, Susana

    2015-05-01

    Future changes in climate may affect soil nitrogen (N) transformations, and consequently, plant nutrition and N losses from terrestrial to stream ecosystems. We investigated the response of soil N cycling to changes in soil moisture, soil temperature, and precipitation across three Mediterranean forest types (evergreen oak, beech, and riparian) by fusing a simple process-based model (which included climate modifiers for key soil N processes) with measurements of soil organic N content, mineralization, nitrification, and concentration of ammonium and nitrate. The model describes sources (atmospheric deposition and net N mineralization) and sinks (plant uptake and hydrological losses) of inorganic N from and to the 0-10 cm soil pool as well as net nitrification. For the three forest types, the model successfully recreated the magnitude and temporal pattern of soil N processes and N concentrations (Nash-Sutcliffe coefficient = 0.49-0.96). Changes in soil water availability drove net N mineralization and net nitrification at the oak and beech forests, while temperature and precipitation were the strongest climatic factors for riparian soil N processes. In most cases, net N mineralization and net nitrification showed a different sensitivity to climatic drivers (temperature, soil moisture, and precipitation). Our model suggests that future climate change may have a minimal effect on the soil N cycle of these forests (<10% change in mean annual rates) because positive warming and negative drying effects on the soil N cycle may counterbalance each other.

  13. Forest Owners' Response to Climate Change: University Education Trumps Value Profile.

    PubMed

    Blennow, Kristina; Persson, Johannes; Persson, Erik; Hanewinkel, Marc

    2016-01-01

    Do forest owners' levels of education or value profiles explain their responses to climate change? The cultural cognition thesis (CCT) has cast serious doubt on the familiar and often criticized "knowledge deficit" model, which says that laypeople are less concerned about climate change because they lack scientific knowledge. Advocates of CCT maintain that citizens with the highest degrees of scientific literacy and numeracy are not the most concerned about climate change. Rather, this is the group in which cultural polarization is greatest, and thus individuals with more limited scientific literacy and numeracy are more concerned about climate change under certain circumstances than those with higher scientific literacy and numeracy. The CCT predicts that cultural and other values will trump the positive effects of education on some forest owners' attitudes to climate change. Here, using survey data collected in 2010 from 766 private forest owners in Sweden and Germany, we provide the first evidence that perceptions of climate change risk are uncorrelated with, or sometimes positively correlated with, education level and can be explained without reference to cultural or other values. We conclude that the recent claim that advanced scientific literacy and numeracy polarizes perceptions of climate change risk is unsupported by the forest owner data. In neither of the two countries was university education found to reduce the perception of risk from climate change. Indeed in most cases university education increased the perception of risk. Even more importantly, the effect of university education was not dependent on the individuals' value profile. PMID:27223473

  14. Ground-Based Lidar Measurements of Forest Canopy Structure as Predictors of Net Primary Production Across Successional Time

    NASA Astrophysics Data System (ADS)

    Scheuermann, C. M.; Gough, C. M.; Nave, L. E.

    2015-12-01

    Forest canopy structure is a key predictor of gas exchange processes that control carbon (C) uptake, including the allocation of photosynthetically fixed C to new plant biomass growth, or net primary production (NPP). Prior work suggests forest canopy structural complexity (CSC), the arrangement of leaves within a volume of canopy, changes as forests develop and is a strong predictor of NPP. However, the expressions of CSC that best predict NPP over decadal to century timescales is unknown. Our objectives were to use multiple remote sensing observations to characterize forest canopy structure in increasing dimensional complexity over a forest age gradient, and to identify which expressions of physical structure best served as proxies of NPP. The study at the University of Michigan Biological Station in Pellston, MI, USA uses two parallel forest chronosequences with different harvesting and fire disturbance histories and includes three old-growth ecosystems varying in canopy composition. We have derived several expressions of 2-D and 3-D forest canopy structure from hemispherical images, a ground-based portable canopy lidar (PCL), and a 3-D terrestrial lidar scanner (TLS), and are relating these structural metrics with NPP and light and nitrogen allocation within the canopy. Preliminary analysis shows that old-growth stands converged on a common mean CSC, but with substantially higher within-stand variation in complexity as deciduous tree species increased in forest canopy dominance. Forest stands that were more intensely disturbed were slower to recover leaf area index (LAI) as they regrew, but 2-D measures of CSC increased similarly as forests aged, regardless of disturbance history. Ongoing work will relate long-term trends in forest CSC with NPP and resource allocation to determine which forest structure remote sensing products are most useful for modeling and scaling C cycling processes through different stages of forest development.

  15. Products equip facilities for effective response

    SciTech Connect

    Not Available

    1993-08-01

    EPA and OSHA require facilities using hazardous materials to have on hand such emergency response tools as PPE, and spill control, cleanup and decontamination equipment. Regulations specifically refer to absorbents for cleaning up possible spills. Many spill response products are available to ensure compliance and preparedness for spills involving hazardous substances. For example, absorbents are composed of diverse materials to provide various levels of chemical compatibility, depending on company requirements. Facilities using hazardous chemicals must inventory their stock to determine what materials they need, including: Selective absorbents to absorb oil and repel water; non-selective absorbents to absorb liquids, although some materials are compatible with some chemicals. Spill kits are convenient containers for spill response products. Kits should be designed to handle the worst possible spill. Although vendors offer numerous standard configurations, customized kits meeting specific facility requirements often are most effective. Finally, spill response products provide effective means for managing hazardous materials releases onsite, but proper training ultimately is the key to accomplishing such tasks effectively.

  16. Information Products Laboratory for Emergency Response - IPLER

    NASA Astrophysics Data System (ADS)

    Vodacek, A.; Boyd, D. L.; van Aardt, J.; Renschler, C. S.; McKeown, D. M.; Collins, H.; Duvvuri, S.; Pillai, A. H.

    2009-12-01

    The three-tiered disaster management approach, disaster planning, disaster response and disaster recovery, is ripe for innovation through integrated knowledge and technology transfer efforts between university researchers, technology companies, and public sector responders. We have formed a partnership, the Information Products Laboratory for Emergency Response or IPLER, dedicated to innovation in disaster management by the appropriate application of remote sensing and geospatial technologies. The mission of the IPLER is to create a technology, policy, and business development incubator to facilitate interaction and innovation among university researchers, private sector service and product providers, and public sector emergency response decision makers. Our initial demonstration projects involve flood and wildland fire mapping. The initial results highlight the utility of integrated multispectral imaging and lidar sensing with terrain and hydrologic modeling for managing areas affected by the 2009 flooding of Cattaraugus Creek, NY, USA. Additionally, our processing flow for multispectral (mid- and longwave IR) remote sensing data of wildfire is an example of near realtime transformation of imaging data into simplified information products for use in wildland fire response.

  17. Threshold responses of songbirds to long-term timber management on an active industrial forest

    USGS Publications Warehouse

    Becker, D.A.; Wood, P.B.; Keyser, P.D.; Wigley, T.B.; Dellinger, R.; Weakland, C.A.

    2011-01-01

    Forest managers often seek to balance economic benefits from timber harvesting with maintenance of habitat for wildlife, ecosystem function, and human uses. Most research on the relationship between avian abundance and active timber management has been short-term, lasting one to two years, creating the need to investigate long-term avian responses and to identify harvest thresholds when a small change in habitat results in a disproportionate response in relative abundance and nest success. Our objectives were to identify trends in relative abundance and nest success and to identify landscape-scale disturbance thresholds for avian species and habitat guilds in response to a variety of harvest treatments (clear-cuts, heavy and light partial harvests) over 14 years. We conducted point counts and monitored nests at an industrial forest in the central Appalachians of West Virginia during 1996-1998, 2001-2003, and 2007-2009. Early successional species increased in relative abundance across all three time periods, whereas interior-edge and forest-interior guilds peaked in relative abundance mid-study after which the forest-interior guild declined. Of 41 species with >10 detections, four (10%) declined significantly, 13 (32%) increased significantly (only three species among all periods), and 9 (22%) peaked in abundance mid-study (over the entire study period, four species had no significant change in abundance, four declined, and one increased). Based on piecewise linear models, forest-interior and interior-edge guilds' relative abundance harvest thresholds were 28% total harvests (all harvests combined), 10% clear-cut harvests, and 18% light partial harvests, after which abundances declined. Harvest thresholds for the early successional guild were 42% total harvests, 11% clear-cut harvest, and 10% light partial harvests, and relative abundances increased after surpassing thresholds albeit at a reduced rate of increase after the clear-cut threshold. Threshold confidence

  18. Understanding Tropical Forest Response to Seasonal and Interannual Variability: The Goldilocks Problem

    NASA Astrophysics Data System (ADS)

    Baker, I. T.; Berry, J. A.; Harper, A. B.; Denning, A. S.; Lee, J. E.; Joiner, J.; Frankenberg, C.

    2015-12-01

    Quantifying our understanding of tropical forest response to seasonal cycles of precipitation, and variability around the annual mean, is an ongoing problem. A decade ago, computer models were unable to reproduce forest behavior at some forests in tropical South America, with the result that ecophysiological function collapsed and Bowen ratio spiked unrealistially during the dry season. Subsequent work has mitigated this oversensitivity to annual cycles of rainy and dry seasons, with the result that our models may now be under-sensitive to variability around the mean. Hence the Goldilocks metaphor: We have moved our models from an over-sensitive (too hot) position to an under-sensitive (too cold) state, while we desire understanding and an ability to simulate both annual cycles and anomalous conditions (just right). In this research we demonstrate our ability to combine in-situ and spectral datasets with models to converge on a description of biophysical processes that combines robustness to mean annual state with a realistic sensitivity to anomalous drought. We use climatology of annual mean precipitation and dry season character to obtain a Drought Resistance Index (DRI) that, when combined with soil depth data yields an initial estimate of forest drought resilience. Solar-Induced Fluorescence (SIF) observations provide higher-resolution spatiotemporal monitoring of canopy response to anomalous events (such as 2010 drought) that can we use to refine our understanding of ecophysiological stress across temperature and precipitation gradients in tropical South America. We demonstrate that we can maintain fidelity to seasonality of surface flux as observed by eddy covariance flux towers while improving model response to drought events.

  19. Numerical and functional responses of forest bats to a major insect pest in pine plantations.

    PubMed

    Charbonnier, Yohan; Barbaro, Luc; Theillout, Amandine; Jactel, Hervé

    2014-01-01

    Global change is expected to modify the frequency and magnitude of defoliating insect outbreaks in forest ecosystems. Bats are increasingly acknowledged as effective biocontrol agents for pest insect populations. However, a better understanding is required of whether and how bat communities contribute to the resilience of forests to man- and climate-driven biotic disturbances.We studied the responses of forest insectivorous bats to a major pine defoliator, the pine processionary moth Thaumetopoea pityocampa, which is currently expanding its range in response to global warming [corrected]. We used pheromone traps and ultrasound bat recorders to estimate the abundance and activity of moths and predatory bats along the edge of infested pine stands. We used synthetic pheromone to evaluate the effects of experimentally increased moth availability on bat foraging activity. We also evaluated the top-down regulation of moth population by estimating T. pityocampa larval colonies abundance on the same edges the following winter. We observed a close spatio-temporal matching between emergent moths and foraging bats, with bat activity significantly increasing with moth abundance. The foraging activity of some bat species was significantly higher near pheromone lures, i.e. in areas of expected increased prey availability. Furthermore moth reproductive success significantly decreased with increasing bat activity during the flight period of adult moths. These findings suggest that bats, at least in condition of low prey density, exhibit numerical and functional responses to a specific and abundant prey, which may ultimately result in an effective top-down regulation of the population of the prey. These observations are consistent with bats being useful agents for the biocontrol of insect pest populations in plantation forests. PMID:25285523

  20. Numerical and Functional Responses of Forest Bats to a Major Insect Pest in Pine Plantations

    PubMed Central

    Charbonnier, Yohan; Barbaro, Luc; Theillout, Amandine; Jactel, Hervé

    2014-01-01

    Global change is expected to modify the frequency and magnitude of defoliating insect outbreaks in forest ecosystems. Bats are increasingly acknowledged as effective biocontrol agents for pest insect populations. However, a better understanding is required of whether and how bat communities contribute to the resilience of forests to man- and climate-driven biotic disturbances. We studied the responses of forest insectivorous bats to a major pine defoliator, the pine processionary moth pityocampa, which is currently expanding its range in response to global warming. We used pheromone traps and ultrasound bat recorders to estimate the abundance and activity of moths and predatory bats along the edge of infested pine stands. We used synthetic pheromone to evaluate the effects of experimentally increased moth availability on bat foraging activity. We also evaluated the top-down regulation of moth population by estimating T. pityocampa larval colonies abundance on the same edges the following winter. We observed a close spatio-temporal matching between emergent moths and foraging bats, with bat activity significantly increasing with moth abundance. The foraging activity of some bat species was significantly higher near pheromone lures, i.e. in areas of expected increased prey availability. Furthermore moth reproductive success significantly decreased with increasing bat activity during the flight period of adult moths. These findings suggest that bats, at least in condition of low prey density, exhibit numerical and functional responses to a specific and abundant prey, which may ultimately result in an effective top-down regulation of the population of the prey. These observations are consistent with bats being useful agents for the biocontrol of insect pest populations in plantation forests. PMID:25285523

  1. Seedling growth responses to soil resources in the understory of a wet tropical forest.

    PubMed

    Holste, Ellen K; Kobe, Richard K; Vriesendorp, Corine F

    2011-09-01

    Plant growth responses to resources may be an important mechanism that influences species' distributions, coexistence, and community structure. Irradiance is considered the most important resource for seedling growth in the understory of wet tropical forests, but multiple soil nutrients and species have yet to be examined simultaneously with irradiance under field conditions. To identify potentially limiting resources, we modeled tree seedling growth as a function of irradiance and soil nutrients across five sites, spanning a soil fertility gradient in old-growth, wet tropical forests at La Selva Biological Station, Costa Rica. We measured an array of soil nutrients including total nitrogen (total N), inorganic N (nitrate [NO3-] and ammonium [NH4+]), phosphate (PO4-), and sum of base cations (SBC; potassium, magnesium, and calcium). Shade in the forest understory did not preclude seedling growth correlations with soil nutrients. Irradiance was a significant predictor of growth in 52% of the species, inorganic N in 54% (NO3- in 32%; NH4+ in 34%), total N in 47%, SBC in 39%, and PO4- in 29%. Overall, growth was correlated with both irradiance and soil nutrients in 45% of species and with soil nutrients only in an additional 48%; rarely was irradiance alone correlated with growth. Contrary to expectations, the magnitudes of growth effects, assessed as the maximum growth response to significant resources for each species, were similar for irradiance and most soil nutrients. Among species whose growth correlated with soil nutrients, the rank importance of nutrient effects was SBC, followed by N (total N, NO3-, and/or NH4+) and PO4-. Species' growth responsiveness (i.e., magnitudes of effect) to irradiance and soil nutrients was negatively correlated with species' shade tolerance (survival under 1% full sun). In this broad survey of species and resources, the nearly ubiquitous effects of soil nutrients on seedling growth challenge the idea that soil nutrients are less

  2. Analysing Amazonian forest productivity using a new individual and trait-based model (TFS v.1)

    NASA Astrophysics Data System (ADS)

    Fyllas, N. M.; Gloor, E.; Mercado, L. M.; Sitch, S.; Quesada, C. A.; Domingues, T. F.; Galbraith, D. R.; Torre-Lezama, A.; Vilanova, E.; Ramírez-Angulo, H.; Higuchi, N.; Neill, D. A.; Silveira, M.; Ferreira, L.; Aymard C., G. A.; Malhi, Y.; Phillips, O. L.; Lloyd, J.

    2014-07-01

    Repeated long-term censuses have revealed large-scale spatial patterns in Amazon basin forest structure and dynamism, with some forests in the west of the basin having up to a twice as high rate of aboveground biomass production and tree recruitment as forests in the east. Possible causes for this variation could be the climatic and edaphic gradients across the basin and/or the spatial distribution of tree species composition. To help understand causes of this variation a new individual-based model of tropical forest growth, designed to take full advantage of the forest census data available from the Amazonian Forest Inventory Network (RAINFOR), has been developed. The model allows for within-stand variations in tree size distribution and key functional traits and between-stand differences in climate and soil physical and chemical properties. It runs at the stand level with four functional traits - leaf dry mass per area (Ma), leaf nitrogen (NL) and phosphorus (PL) content and wood density (DW) varying from tree to tree - in a way that replicates the observed continua found within each stand. We first applied the model to validate canopy-level water fluxes at three eddy covariance flux measurement sites. For all three sites the canopy-level water fluxes were adequately simulated. We then applied the model at seven plots, where intensive measurements of carbon allocation are available. Tree-by-tree multi-annual growth rates generally agreed well with observations for small trees, but with deviations identified for larger trees. At the stand level, simulations at 40 plots were used to explore the influence of climate and soil nutrient availability on the gross (ΠG) and net (ΠN) primary production rates as well as the carbon use efficiency (CU). Simulated ΠG, ΠN and CU were not associated with temperature. On the other hand, all three measures of stand level productivity were positively related to both mean annual precipitation and soil nutrient status

  3. Forest carbon response to management scenarios intended to mitigate GHG emissions and reduce fire impacts in the US West Coast region

    NASA Astrophysics Data System (ADS)

    Hudiburg, T. W.; Law, B. E.; Thornton, P. E.; Luyssaert, S.

    2012-12-01

    US West coast forests are among the most carbon dense biomes in the world and the potential for biomass accumulation in mesic coastal forests is the highest recorded (Waring and Franklin 1979, Hudiburg et al. 2009). Greenhouse gas (GHG) mitigation strategies have recently expanded to include forest woody biomass as bioenergy, with the expectation that this will also reduce forest mortality. We examined forest carbon response and life cycle assessment (LCA) of net carbon emissions following varying combinations of bioenergy management scenarios in Pacific Northwest forests for the period from 2010-2100. We use the NCAR CLM4 model combined with a regional atmospheric forcing dataset and account for future environmental change using the IPCC RCP4.5 and RCP 8.5 scenarios. Bioenergy management strategies include a repeated thinning harvest, a repeated clearcut harvest, and a single salvage harvest in areas with projected insect-related mortality. None of the bioenergy management scenarios reduce net emissions to the atmosphere compared to continued business-as-usual harvest (BAU) by the end of the 21st century. Forest regrowth and reduced fire emissions are not large enough to balance the wood removals from harvest. Moreover, the substitution of wood for fossil fuel energy and products is not large enough to offset the wood losses through decomposition and combustion. However, in some ecoregions (Blue Mountains and East Cascades), emissions from the thinning harvests begin to improve over BAU at the end of the century and could lead to net reductions in those ecoregions over a longer time period (> 100 years). For salvage logging, there is no change compared to BAU emissions by the end of the 21st century because the treatment area is minimal compared to the other treatments and only performed once. These results suggest that managing forests for carbon sequestration will need to include a variety of approaches accounting for forest baseline conditions and in some

  4. Runoff Responses to Forest Thinning at Plot and Catchment Scales in a Headwater Catchment Draining Japanese Cypress Forest

    EPA Science Inventory

    We examined the effect of forest thinning on runoff generation at plot and catchment scales in headwater basins draining a Japanese cypress (Chamaecyparis obtusa) forest. We removed 58.3% of the stems (corresponding to 43.2% of the basal area) in the treated headwater basin (catc...

  5. Microbial community response to permafrost thaw after wildfire in an Alaskan upland boreal forest

    NASA Astrophysics Data System (ADS)

    Tas, N.; Jorgenson, M. T.; Wang, S.; Berhe, A. A.; Wickland, K. P.; Waldrop, M. P.; Jansson, J. K.

    2012-12-01

    , transition and permafrost layers. Fire impacted locations were characterized with higher pH, soil moisture, and dissolved organic carbon concentrations compared to control locations. CO2 and CH4 fluxes were lower in burned sites compared to control sites, particularly at the depth of permafrost. In contrast, N2O production was higher in burned soils. All of the enzymes had significantly lower activity in fire affected locations than in controls. There were no major differences in the microbial diversity of active layers between fire impacted and control locations. However, microbial diversity was lower in thawed permafrost layers of the burned samples compared to the controls. At all depths the microbial community composition was significantly different between burned and unburned sites. Metagenome sequencing revealed reduced metabolic capacity in genes for sugar and carbohydrate processing in burned active layer soils, whereas some genes for other processes such as stress response were enriched in thawed permafrost layers. In this ongoing project, microbial communities and processes will be further investigated to determine linkages between genomics, enzyme activities, and greenhouse gas fluxes.

  6. Development of 4π Electro-Magnetic Calorimeter Complex Forest for Neutral Meson Photo-Production Experiments

    NASA Astrophysics Data System (ADS)

    Suzuki, K.; Fujimura, H.; Fukasawa, H.; Hashimoto, R.; Ishikawa, T.; Kasagi, J.; Kuwasaki, S.; Mochizuki, K.; Nawa, K.; Okada, Y.; Onodera, Y.; Sato, M.; Shimizu, H.; Yamazaki, H.; Kawano, A.; Sakamoto, Y.; Maeda, K.

    2010-10-01

    A large solid angle electro-magnetic calorimeter system, FOREST, has been constructed at LNB-Sendai to study the π0 and η photo-production reactions. FOREST consists of three electro-magnetic calorimeters: pure CsI crystals, Lead/SciFi blocks and Lead Glass Cherenkov counters. It covers about 90% of the total solid angle.

  7. Predicting the response of a temperate forest ecosystem to atmospheric CO[sub 2] increase

    SciTech Connect

    Bazzaz, F.A.

    1993-01-01

    This report summarizes the second year of research progress. Included are progress reports for the following studies: the responses of temperate forest tree to 3 years of exposure to elevated carbon dioxide, and high and low nutrient and light levels; pot-size limitations in carbon dioxide studies, interactive effects of carbon dioxide and soil moisture availability on tree seedling's tissue water relations, growth, and niche characteristics; individual versus population responses to elevated carbon dioxide levels in two species of annual weeds; and the development of gypsy moth larvae raised on gray and yellow birth foliage grown in ambient and elevated carbon dioxide environments.

  8. Deciduous forest responses to temperature, precipitation, and drought imply complex climate change impacts.

    PubMed

    Xie, Yingying; Wang, Xiaojing; Silander, John A

    2015-11-01

    Changes in spring and autumn phenology of temperate plants in recent decades have become iconic bio-indicators of rapid climate change. These changes have substantial ecological and economic impacts. However, autumn phenology remains surprisingly little studied. Although the effects of unfavorable environmental conditions (e.g., frost, heat, wetness, and drought) on autumn phenology have been observed for over 60 y, how these factors interact to influence autumn phenological events remain poorly understood. Using remotely sensed phenology data from 2001 to 2012, this study identified and quantified significant effects of a suite of environmental factors on the timing of fall dormancy of deciduous forest communities in New England, United States. Cold, frost, and wet conditions, and high heat-stress tended to induce earlier dormancy of deciduous forests, whereas moderate heat- and drought-stress delayed dormancy. Deciduous forests in two eco-regions showed contrasting, nonlinear responses to variation in these explanatory factors. Based on future climate projection over two periods (2041-2050 and 2090-2099), later dormancy dates were predicted in northern areas. However, in coastal areas earlier dormancy dates were predicted. Our models suggest that besides warming in climate change, changes in frost and moisture conditions as well as extreme weather events (e.g., drought- and heat-stress, and flooding), should also be considered in future predictions of autumn phenology in temperate deciduous forests. This study improves our understanding of how multiple environmental variables interact to affect autumn phenology in temperate deciduous forest ecosystems, and points the way to building more mechanistic and predictive models. PMID:26483475

  9. Deciduous forest responses to temperature, precipitation, and drought imply complex climate change impacts

    PubMed Central

    Xie, Yingying; Wang, Xiaojing; Silander, John A.

    2015-01-01

    Changes in spring and autumn phenology of temperate plants in recent decades have become iconic bio-indicators of rapid climate change. These changes have substantial ecological and economic impacts. However, autumn phenology remains surprisingly little studied. Although the effects of unfavorable environmental conditions (e.g., frost, heat, wetness, and drought) on autumn phenology have been observed for over 60 y, how these factors interact to influence autumn phenological events remain poorly understood. Using remotely sensed phenology data from 2001 to 2012, this study identified and quantified significant effects of a suite of environmental factors on the timing of fall dormancy of deciduous forest communities in New England, United States. Cold, frost, and wet conditions, and high heat-stress tended to induce earlier dormancy of deciduous forests, whereas moderate heat- and drought-stress delayed dormancy. Deciduous forests in two eco-regions showed contrasting, nonlinear responses to variation in these explanatory factors. Based on future climate projection over two periods (2041–2050 and 2090–2099), later dormancy dates were predicted in northern areas. However, in coastal areas earlier dormancy dates were predicted. Our models suggest that besides warming in climate change, changes in frost and moisture conditions as well as extreme weather events (e.g., drought- and heat-stress, and flooding), should also be considered in future predictions of autumn phenology in temperate deciduous forests. This study improves our understanding of how multiple environmental variables interact to affect autumn phenology in temperate deciduous forest ecosystems, and points the way to building more mechanistic and predictive models. PMID:26483475

  10. Soil microbial responses to forest floor litter manipulation and nitrogen addition in a mixed-wood forest of northern China.

    PubMed

    Sun, Xiao-Lu; Zhao, Jing; You, Ye-Ming; Jianxin Sun, Osbert

    2016-01-01

    Changes in litterfall dynamics and soil properties due to anthropogenic or natural perturbations have important implications to soil carbon (C) and nutrient cycling via microbial pathway. Here we determine soil microbial responses to contrasting types of litter inputs (leaf vs. fine woody litter) and nitrogen (N) deposition by conducting a multi-year litter manipulation and N addition experiment in a mixed-wood forest. We found significantly higher soil organic C, total N, microbial biomass C (MBC) and N (MBN), microbial activity (MR), and activities of four soil extracellular enzymes, including β-glucosidase (BG), N-acetyl-β-glucosaminidase (NAG), phenol oxidase (PO), and peroxidase (PER), as well as greater total bacteria biomass and relative abundance of gram-negative bacteria (G-) community, in top soils of plots with presence of leaf litter than of those without litter or with presence of only fine woody litter. No apparent additive or interactive effects of N addition were observed in this study. The occurrence of more labile leaf litter stimulated G-, which may facilitate microbial community growth and soil C stabilization as inferred by findings in literature. A continued treatment with contrasting types of litter inputs is likely to result in divergence in soil microbial community structure and function. PMID:26762490

  11. Soil microbial responses to forest floor litter manipulation and nitrogen addition in a mixed-wood forest of northern China

    PubMed Central

    Sun, Xiao-Lu; Zhao, Jing; You, Ye-Ming; Jianxin Sun, Osbert

    2016-01-01

    Changes in litterfall dynamics and soil properties due to anthropogenic or natural perturbations have important implications to soil carbon (C) and nutrient cycling via microbial pathway. Here we determine soil microbial responses to contrasting types of litter inputs (leaf vs. fine woody litter) and nitrogen (N) deposition by conducting a multi-year litter manipulation and N addition experiment in a mixed-wood forest. We found significantly higher soil organic C, total N, microbial biomass C (MBC) and N (MBN), microbial activity (MR), and activities of four soil extracellular enzymes, including β-glucosidase (BG), N-acetyl-β-glucosaminidase (NAG), phenol oxidase (PO), and peroxidase (PER), as well as greater total bacteria biomass and relative abundance of gram-negative bacteria (G-) community, in top soils of plots with presence of leaf litter than of those without litter or with presence of only fine woody litter. No apparent additive or interactive effects of N addition were observed in this study. The occurrence of more labile leaf litter stimulated G-, which may facilitate microbial community growth and soil C stabilization as inferred by findings in literature. A continued treatment with contrasting types of litter inputs is likely to result in divergence in soil microbial community structure and function. PMID:26762490

  12. Forest soil carbon oxidation state and oxidative ratio responses to elevated CO2

    NASA Astrophysics Data System (ADS)

    Hockaday, William C.; Gallagher, Morgan E.; Masiello, Caroline A.; Baldock, Jeffrey A.; Iversen, Colleen M.; Norby, Richard J.

    2015-09-01

    The oxidative ratio (OR) of the biosphere is the stoichiometric ratio (O2/CO2) of gas exchange by photosynthesis and respiration—a key parameter in budgeting calculations of the land and ocean carbon sinks. Carbon cycle-climate feedbacks could alter the OR of the biosphere by affecting the quantity and quality of organic matter in plant biomass and soil carbon pools. This study considers the effect of elevated atmospheric carbon dioxide concentrations ([CO2]) on the OR of a hardwood forest after nine growing seasons of Free-Air CO2 Enrichment. We measured changes in the carbon oxidation state (Cox) of biomass and soil carbon pools as a proxy for the ecosystem OR. The OR of net primary production, 1.039, was not affected by elevated [CO2]. However, the Cox of the soil carbon pool was 40% higher at elevated [CO2], and the estimated OR values for soil respiration increased from 1.006 at ambient [CO2] to 1.054 at elevated [CO2]. A biochemical inventory of the soil organic matter ascribed the increases in Cox and OR to faster turnover of reduced substrates, lignin and lipids, at elevated [CO2]. This implicates the heterotrophic soil community response to elevated [CO2] as a driver of disequilibrium in the ecosystem OR. The oxidation of soil carbon pool constitutes an unexpected terrestrial O2 sink. Carbon budgets constructed under the assumption of OR equilibrium would equate such a terrestrial O2 sink to CO2 uptake by the ocean. The potential for climate-driven disequilibriua in the cycling of O2 and CO2 warrants further investigation.

  13. Forests of Mexico

    SciTech Connect

    Cairns, M.A.; Dirzo, R.; Zadroga, F.

    1995-07-01

    Forest of Mexico as elsewhere provide essential goods and services for both local citizens and the international community. Benefits include climate regulation, biodiversity, and wood and nonwood products for local consumption and economic activity. Deforestation is a matter of great environmental and economic concern. This article assesses rates of deforestation, the present status of forest in Mexico, and the major factors responsible for deforestation in the tropical southeastern region.

  14. Operationalizing measurement of forest degradation: Identification and quantification of charcoal production in tropical dry forests using very high resolution satellite imagery

    NASA Astrophysics Data System (ADS)

    Dons, K.; Smith-Hall, C.; Meilby, H.; Fensholt, R.

    2015-07-01

    Quantification of forest degradation in monitoring and reporting as well as in historic baselines is among the most challenging tasks in national REDD+ strategies. However, a recently introduced option is to base monitoring systems on subnational conditions such as prevalent degradation activities. In Tanzania, charcoal production is considered a major cause of forest degradation, but is challenging to quantify due to sub-canopy biomass loss, remote production sites and illegal trade. We studied two charcoal production sites in dry Miombo woodland representing open woodland conditions near human settlements and remote forest with nearly closed canopies. Supervised classification and adaptive thresholding were applied on a pansharpened QuickBird (QB) image to detect kiln burn marks (KBMs). Supervised classification showed reasonable detection accuracy in the remote forest site only, while adaptive thresholding was found acceptable at both locations. We used supervised classification and manual digitizing for KBM delineation and found acceptable delineation accuracy at both sites with RMSEs of 25-32% compared to ground measurements. Regression of charcoal production on KBM area delineated from QB resulted in R2s of 0.86-0.88 with cross-validation RMSE ranging from 2.22 to 2.29 Mg charcoal per kiln. This study demonstrates, how locally calibrated remote sensing techniques may be used to identify and delineate charcoal production sites for estimation of charcoal production and associated extraction of woody biomass.