Science.gov

Sample records for adjacent forest stands

  1. 14. Charles Acey Cobb standing adjacent to the fish screen ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Charles Acey Cobb standing adjacent to the fish screen he designed and installed in the Congdon Canal, facing southeast. Photo dates ca. late 1920's. - Congdon Canal, Fish Screen, Naches River, Yakima, Yakima County, WA

  2. Comparison between soil and biomass carbon in adjacent hardwood and red pine forests

    SciTech Connect

    Perala, D.A.; Rollinger, J.L.; Wilson, D.M.

    1995-06-01

    The distribution of carbon in soil and biomass was studied across Minnesota, Wisconsin, and Michigan, USA, in 40 pole-sized red pine (Pinus resinosa Ait.) plantations paired with adjacent hardwood stands. Pine and hardwood stands shared a common boundary and soil. Hardwood stands were mixed species, naturally regenerated second growth following logging. Carbon in total, standing crop averaged the same in both hardwood and red pine forest types, although the hardwoods averaged 14 years older than red pine. Coarse woody debris, shrubs, and herbs contained little carbon. Only the forest floor carbon pool was significantly different between forest types. Forest floor had a greater mass beneath red pine than hardwoods. There was no difference in total ecosystem carbon between red pine and hardwood stands. Total mineral soil aggregated across the depth profile contained the same total amount of carbon in both pine and hardwood stands; however, the carbon was found in different vertical patterns. Amounts of carbon in the upper levels of soil (0--4 cm) were higher under hardwoods, and amounts were higher under red pine at the 8--16 cm and 16--32 cm soil depths. Where July air temperatures were relatively cool, red pine stored carbon more efficiently both in the forest floor and deep in the soil. Red pine also sequestered more carbon in mineral soil with increasing April--September precipitation.

  3. Can native clonal moso bamboo encroach on adjacent natural forest without human intervention?

    PubMed

    Bai, Shangbin; Wang, Yixiang; Conant, Richard T; Zhou, Guomo; Xu, Yong; Wang, Nan; Fang, Feiyan; Chen, Juan

    2016-01-01

    Native species are generally thought not to encroach on adjacent natural forest without human intervention. However, the phenomenon that native moso bamboo may encroach on surrounding natural forests by itself occurred in China. To certificate this encroaching process, we employed the transition front approach to monitor the native moso bamboo population dynamics in native Chinese fir and evergreen broadleaved forest bordering moso bamboo forest in Tianmu Mountain Nature Reserve during the period between 2005 and 2014. The results showed that the bamboo front moved toward the Chinese fir/evergreen broadleaved stand with the new bamboo produced yearly. Moso bamboo encroached at a rate of 1.28 m yr(-1) in Chinese fir forest and 1.04 m yr(-1) in evergreen broadleaved forest, and produced 533/437 new culms hm(-2) yr(-1) in the encroaching natural Chinese fir/evergreen broadleaved forest. Moso bamboo coverage was increasing while adjacent natural forest area decreasing continuously. These results indicate that native moso bamboo was encroaching adjacent natural forest gradually without human intervention. It should be considered to try to create a management regime that humans could selectively remove culms to decrease encroachment. PMID:27600881

  4. Can native clonal moso bamboo encroach on adjacent natural forest without human intervention?

    PubMed Central

    Bai, Shangbin; Wang, Yixiang; Conant, Richard T.; Zhou, Guomo; Xu, Yong; Wang, Nan; Fang, Feiyan; Chen, Juan

    2016-01-01

    Native species are generally thought not to encroach on adjacent natural forest without human intervention. However, the phenomenon that native moso bamboo may encroach on surrounding natural forests by itself occurred in China. To certificate this encroaching process, we employed the transition front approach to monitor the native moso bamboo population dynamics in native Chinese fir and evergreen broadleaved forest bordering moso bamboo forest in Tianmu Mountain Nature Reserve during the period between 2005 and 2014. The results showed that the bamboo front moved toward the Chinese fir/evergreen broadleaved stand with the new bamboo produced yearly. Moso bamboo encroached at a rate of 1.28 m yr−1 in Chinese fir forest and 1.04 m yr−1 in evergreen broadleaved forest, and produced 533/437 new culms hm−2 yr−1 in the encroaching natural Chinese fir/evergreen broadleaved forest. Moso bamboo coverage was increasing while adjacent natural forest area decreasing continuously. These results indicate that native moso bamboo was encroaching adjacent natural forest gradually without human intervention. It should be considered to try to create a management regime that humans could selectively remove culms to decrease encroachment. PMID:27600881

  5. Volatile components in forest stands of Karelia

    SciTech Connect

    Fuksman, I.L.

    1995-09-01

    Study of the qualitative and quantitative composition of volatile organic compounds in forests stands of Karelia is made. A decrease in temperature and an increase in the relative air humidity adversely affect their emission. To study the relationship between the processes of the synthesis of essential oils in woody plants and the release of their components into the environment, a qualitative and quantitative determination of essential oils in pine branches was carried out. 13 refs., 3 figs., 4 tabs.

  6. Mapping of sites in forest stands.

    PubMed

    Netto, Sylvio Péllico; Stefanello, Flavio R; Pelissari, Allan L; David, Hassan C

    2014-12-01

    Generally, the forest companies use the total one year planting area as a minimum stratum of the total population and, consequently, the forest inventory processing has been conducted by applying the stratified random sampling to it. This study was carried out in the National Forest of Tres Barras, Brazil, and it aimed to classify and map the sites of Pinus elliottii stands. A systematic sampling was structured into clusters and applied independently by compartments. The clusters, in maltese cross, were composed of four sampling subunits, using Prodan sampling method with a fixed number of six trees. By analysis of the methodology it was possible to confirm the hypothesis: a) the selective thinning cause expressive increase of volumetric variability within compartments; b) the variation of sites within the compartments causes volumetric expansion of variance and this grows proportionally to the quality of the sites; c) the stratification in sites results in minimum variance within them; d) the stratification in sites resulted in until to 91% reduction of variances within them. PMID:25590737

  7. Augmenting Forest Stand Parameters using Landsat TM Spectral Images

    NASA Astrophysics Data System (ADS)

    Reuveni, Y.; Dahan, E.; Anker, Y.; Sprintsin, M.

    2015-12-01

    Forest stand parameters, such as diameter at breast height (DBH), tree height (H), or volume per hectare (V), are imperative for forest resources assessment. Traditional inventory of forest stand parameters, usually based on fieldwork, is often difficult, time-consuming, and expensive, to conduct in large areas. Therefore, estimating forest stand parameters in large areas using traditional inventory approach augmented by satellites data has a significant implication for sustainable forest management and natural resources efficiency. However, obtaining suitable satellite image data for such purpose is a challenging task mainly because of insignificant knowledge between the forest stand parameters and satellite spectral response relationships. Here, we present the use of Landsat Thematic Mapper (TM) spectral responses data for augmenting forest stand parameter obtained from fieldwork at the Lahav Forest, in the Israeli Northern Negev. A new algorithm was developed in order to use all eight TM band when calculating the linear combination which correlates the most to each one of the forest stand parameters. Each linear combination is obtained first for local area inside the entire studied grid and is then fitted using a simple linear polynomial curve to the known forest stand parameter. Once the relationship between the two is characterized by a linear polynomial equation, the TM linear combination local area data is translated to the same equivalent area of the chosen forest stand parameter. At last, we interpolate the entire TM grid using a higher order polynomial fit applied to all the augmented local area combined together to attain full coverage of the desired forest stand parameter.

  8. Relating P-band AIRSAR backscatter to forest stand parameters

    NASA Technical Reports Server (NTRS)

    Wang, Yong; Melack, John M.; Davis, Frank W.; Kasischke, Eric S.; Christensen, Norman L., Jr.

    1993-01-01

    As part of research on forest ecosystems, the Jet Propulsion Laboratory (JPL) and collaborating research teams have conducted multi-season airborne synthetic aperture radar (AIRSAR) experiments in three forest ecosystems including temperate pine forest (Duke, Forest, North Carolina), boreal forest (Bonanza Creek Experimental Forest, Alaska), and northern mixed hardwood-conifer forest (Michigan Biological Station, Michigan). The major research goals were to improve understanding of the relationships between radar backscatter and phenological variables (e.g. stand density, tree size, etc.), to improve radar backscatter models of tree canopy properties, and to develop a radar-based scheme for monitoring forest phenological changes. In September 1989, AIRSAR backscatter data were acquired over the Duke Forest. As the aboveground biomass of the loblolly pine forest stands at Duke Forest increased, the SAR backscatter at C-, L-, and P-bands increased and saturated at different biomass levels for the C-band, L-band, and P-band data. We only use the P-band backscatter data and ground measurements here to study the relationships between the backscatter and stand density, the backscatter and mean trunk dbh (diameter at breast height) of trees in the stands, and the backscatter and stand basal area.

  9. Snow Distribution Patterns in Clearings and Adjacent Forest

    NASA Astrophysics Data System (ADS)

    Golding, Douglas L.; Swanson, Robert H.

    1986-12-01

    Snow accumulation patterns were determined for clearings and adjacent forest at Marmot Creek experimental watershed and James River, Alberta. At maximum accumulation snow water equivalent (SWE) was greater in clearings than in forest whether clearings were large, as in 8- to 13-ha blocks where SWE averaged 20% more than in the forest, or small as in the ¼ to 6-H (height) diameter circular clearings where SWE was 13-45% greater than in the forest. SWE was 42 to 52% less in north than in south sectors of 2-6 H clearings. These differences increased with clearing size and time since beginning of accumulation period and are caused by snow ablation (melt and evaporation), a function of direct solar radiation reaching the snowpack. In such situations the snow that has accumulated on the ground cannot be considered a measure of the snow that has actually fallen there. For water balances and hydrologic modeling, snow measurements in partially cleared watersheds must be adjusted for temporal and spatial factors specific to the watershed.

  10. Soil sustainability study in Lithuanian alien forest stands

    NASA Astrophysics Data System (ADS)

    Čiuldiene, Dovile; Skridlaite, Grazina; Žalūdiene, Gaile; Askelsson, Cecilia; Armolaitis, Kestutis

    2016-04-01

    Tree species are shifting their natural ranges in response to climate changes (Saltré et al., 2013). Northern red oak has originated from North America, but was planted in Europe already in twentieth century. At present, it is considered as invasive species in Poland and at invasive stage in the Lithuanian forests (Riepsas and Straigyte, 2008). European larch naturally grows in Central Europe, but its range has been extended by planting it as far as the Nordic countries. According to a pollen study in peat soils, European larch naturally grew in Lithuania in the sixteenth century and was reintroduced 200 years ago (Jankauskas, 1954). Therefore, the global warming could accelerate the expansion of European larch and Northern red oak into Lithuanian forests. An urgent need appeared to evaluate an impact of those warmth-tolerant species on soil mineral chemistry and quality. New results on the determination of mineral weathering rates in alien forest stands using a PROFILE soil chemistry model were obtained during a doctoral study at the Institute of Forestry. Soil minerals were studied by a Scanning Electron Microscopy at the Institute of Geology and Geography. The results provided a lot of new information on soil weathering rates in Lithuania. The 47 and 157-year-old European larch (Larix decidua Mill.), 45 and 55-year-old Northern red oak (Quercus rubra L.) plantations and adjacent perennial grasslands were chosen for this study. The soils were classified as Luvisols and were developed from glaciofluvial deposits. The PROFILE model requires data of climate conditions (mean annual temperature and precipitation), chemical parameters of atmospheric deposition, forest plantation dendrometric and chemical (wood, foliage litter fall) characteristics, soil physical characteristics and mineral composition. A cation weathering rate (sum of Ca+Mg+ K) is 30% higher in a soil under the Northern red oak than in adjacent perennial grassland. Meanwhile, cation weathering rates

  11. Expansion of forest stands into tundra in the Noatak National Preserve, northwest Alaska

    USGS Publications Warehouse

    Suarez, F.; Binkley, D.; Kaye, M.W.; Stottlemyer, R.

    1999-01-01

    Temperatures across the northern regions of North America have been increasing for 150 years, and forests have responded to this increase. In the Noatak National Preserve in Alaska, white spruce (Picea glauca [Moench] Voss) forests reach their northern limit, occurring primarily on well-drained sites and as gallery forests along streams. Rolling plateaus of tundra separate the white spruce forests into disjunct stands. We examined patterns of tree age, tree growth, and tree encroachment into tundra ecosystems in six stands along the Agashashok River. Warming over the past 150 years appears to have increased tree growth and resulted in forest expansion into adjacent tundra ecosystems. The forest/tundra ecotone shifted by about 80 to 100 m into the tundra in the past 200 years, as evidenced by declining maximum tree age with distance towards the tundra. The decadal-scale pattern of tree establishment at the farthest extent of trees into the tundra (the tundra-forest ecotone) correlated with the detrended growth index for trees within the forests; climate conditions that led to higher tree growth appeared to foster tree establishment in the tundra. This recent forest expansion has occurred across topographic boundaries, from well-drained soils on slopes onto poorly drained, flatter areas of tundra. Further expansion of the forests may be limited by more severe wind exposure and poor drainage that make the majority of tundra less suitable for trees.

  12. Silvicultural guidelines for forest stands threatened by the Gypsy moth. Forest Service general technical report (Final)

    SciTech Connect

    Gottschalk, K.W.

    1993-02-02

    The ecological and silvicultural information on the interaction of gypsy moth and its host forest types is incorporated into silvicultural guidelines for minimizing the impacts of gypsy moth on forest stands threatened by the insect. Decision charts are used to match stand and insect conditions to the proper prescription that includes instructions for implementing it.

  13. Estimation of Stand Height and Forest Volume Using High Resolution Stereo Photography and Forest Type Map

    NASA Astrophysics Data System (ADS)

    Kim, K. M.

    2016-06-01

    Traditional field methods for measuring tree heights are often too costly and time consuming. An alternative remote sensing approach is to measure tree heights from digital stereo photographs which is more practical for forest managers and less expensive than LiDAR or synthetic aperture radar. This work proposes an estimation of stand height and forest volume(m3/ha) using normalized digital surface model (nDSM) from high resolution stereo photography (25cm resolution) and forest type map. The study area was located in Mt. Maehwa model forest in Hong Chun-Gun, South Korea. The forest type map has four attributes such as major species, age class, DBH class and crown density class by stand. Overlapping aerial photos were taken in September 2013 and digital surface model (DSM) was created by photogrammetric methods(aerial triangulation, digital image matching). Then, digital terrain model (DTM) was created by filtering DSM and subtracted DTM from DSM pixel by pixel, resulting in nDSM which represents object heights (buildings, trees, etc.). Two independent variables from nDSM were used to estimate forest stand volume: crown density (%) and stand height (m). First, crown density was calculated using canopy segmentation method considering live crown ratio. Next, stand height was produced by averaging individual tree heights in a stand using Esri's ArcGIS and the USDA Forest Service's FUSION software. Finally, stand volume was estimated and mapped using aerial photo stand volume equations by species which have two independent variables, crown density and stand height. South Korea has a historical imagery archive which can show forest change in 40 years of successful forest rehabilitation. For a future study, forest volume change map (1970s-present) will be produced using this stand volume estimation method and a historical imagery archive.

  14. Forest stand age and the occurrence of chanterelle (Cantharellus) species in Oregon's central Cascade Mountains.

    PubMed

    Dunham, Susie M; O'Dell, Thomas E; Molina, Randy

    2006-12-01

    We describe watershed-scale habitat associations of three Cantharellus species with respect to stand age. During the 1998 autumn fruiting season we collected chanterelle sporocarps from 18 forest stands in and adjacent to the H.J. Andrews experimental forest in the central Cascade Mountains of Oregon. Sampled stands represented two age categories: old growth ( approximately 350+ y) and 40-60-y-old second growth naturally regenerated from clear-cut harvest. Old growth and second growth stands were spatially paired to reduce the chance of spurious habitat relationships caused by unmeasured correlated variables. We found stand age to be a good predictor of the distribution of C. subalbidus and C. formosus, but only marginally useful for predicting the occurrence of C. cascadensis. The odds that a randomly located chanterelle sporocarp will be C. subalbidus, compared to other chanterelles, are 3-23.5 times higher in old growth than in second growth. Alternatively, there is only a 4-38% chance that a randomly located sporocarp will be C. formosus in old growth. C. cascadensis was found to be uncommon throughout the study area and showed no significant habitat associations. The abundance of C. cascadensis increased substantially with decreasing elevation indicating that landscape features other than stand age may be more useful in predicting its occurrence. PMID:17123812

  15. Stand age and climate drive forest carbon balance recovery

    NASA Astrophysics Data System (ADS)

    Besnard, Simon; Carvalhais, Nuno; Clevers, Jan; Herold, Martin; Jung, Martin; Reichstein, Markus

    2016-04-01

    Forests play an essential role in the terrestrial carbon (C) cycle, especially in the C exchanges between the terrestrial biosphere and the atmosphere. Ecological disturbances and forest management are drivers of forest dynamics and strongly impact the forest C budget. However, there is a lack of knowledge on the exogenous and endogenous factors driving forest C recovery. Our analysis includes 68 forest sites in different climate zones to determine the relative influence of stand age and climate conditions on the forest carbon balance recovery. In this study, we only included forest regrowth after clear-cut stand replacement (e.g. harvest, fire), and afforestation/reforestation processes. We synthesized net ecosystem production (NEP), gross primary production (GPP), ecosystem respiration (Re), the photosynthetic respiratory ratio (GPP to Re ratio), the ecosystem carbon use efficiency (CUE), that is NEP to GPP ratio, and CUEclimax, where GPP is derived from the climate conditions. We implemented a non-linear regression analysis in order to identify the best model representing the C flux patterns with stand age. Furthermore, we showed that each C flux have a non-linear relationship with stand age, annual precipitation (P) and mean annual temperature (MAT), therefore, we proposed to use non-linear transformations of the covariates for C fluxes'estimates. Non-linear stand age and climate models were, therefore, used to establish multiple linear regressions for C flux predictions and for determining the contribution of stand age and climate in forest carbon recovery. Our findings depicted that a coupled stand age-climate model explained 33% (44%, average site), 62% (76%, average site), 56% (71%, average site), 41% (59%, average site), 50% (65%, average site) and 36% (50%, average site) of the variance of annual NEP, GPP, Re, photosynthetic respiratory ratio, CUE and CUEclimax across sites, respectively. In addition, we showed that gross fluxes (e.g. GPP and Re) are

  16. Forest stand development patterns in the southern Appalachians

    SciTech Connect

    Copenheaver, C.A.; Matthews, J.M.; Showalter, J.M.; Auch, W.E.

    2006-07-01

    Composition of southern Appalachian forests are influenced by disturbance and topography. This study examined six stands in southwestern Virginia. Within each stand, a 0.3-ha plot was established, and all trees and saplings were measured and aged. Burned stands had lower densities of saplings and small trees, but appeared to have greater Quercus regeneration. Ice damage from the 1994 ice storm was most evident in Pinus strobus saplings. A stand on old coal-mine slag appeared to be experiencing a slower rate of succession than other sites. A variety of stand development patterns were observed, but one common pattern was that oak-hickory overstories had different species in their understory, which may indicate future changes in species composition.

  17. The Development of Even-Aged Plantation Forests: An Exercise in Forest Stand Dynamics

    ERIC Educational Resources Information Center

    Wilson, E. R.; Leslie, A. D.

    2008-01-01

    In this paper we present a field-based practical exercise that allows students in forestry, ecology and natural resources to develop their understanding of forest stand dynamics. The exercise involves measurement of key tree growth parameters in four even-aged, single-species plantation stands of different age but occupying sites with similar soil…

  18. Stand hazard rating for central idaho forests. Forest Service general technical report

    SciTech Connect

    Steele, R.; Williams, R.E.; Weatherby, J.C.; Reinhardt, E.D.; Hoffman, J.T.

    1996-03-01

    Growing concern over sustainability of central Idaho forests has created a need to assess the health of forest stands on a relative basis. A stand hazard rating was developed as a composite of 11 individual ratings to compare the health hazards of different stands. The composite rating includes Douglas-fire bettle, mountain pine beetle, western pine beetle, spruce beetle, Douglas-fire tussock moth, western spruce budworm, dwarf mistletoes, annosus root disease, Swhweinitzii root and butt rot, and wildfire. The interacting effects of these agents were also considered.

  19. Extraction of Forest Stands Parameters from Aster Data in Open Forest

    NASA Astrophysics Data System (ADS)

    Abbasi, M.; Riyahi Bakhtyarib, H. R.

    2012-07-01

    Tree crown size (CS) and stem number per hectare (SN) has become increasingly important for forest management and ecosystem monitoring. Tree crown size is also strongly related to other canopy structural parameters, such as diameter at breast height, tree height and biomass. For both issues, remote sensing data are attractive for their large-area and up-to-date mapping capacities. The QuickBird and ASTER imagery used in this study was acquired over Zagros Forests in southern Zagros region, Fars province of Iran on 1 August 2005 and 1 July 2005, respectively. For the forest site investigated in this study, we concentrated on stands of Quercus Persica which is the dominant species in Zagros region. This study was conducted to investigate the capabilities of ASTER-L1B data to estimate some of forest parameters at individual tree and stand level in dry area. The forest stand parameters are crown area, crown density, average crown area. Obtaining the accuracy of classification the ground truth map was prepared by tree crown delineation using the panchromatic band of QuickBird data. Individual tree crowns were automatically delineated by color segmentation of QuickBird imagery. Simple linear regression procedure was used to show the relationships between spectral variables and the individual trees and forest stand parameters. With decreasing the crown density the effects of background will increase. Our results indicated that crown size could be accurately extracted from panchromatic band of QuickBird images especially for open forest stands. This paper demonstrates that using high-resolution satellite imagery in the open forest offers a unique opportunity for deriving single tree attributes and allowing reliable ground truth map to estimate stand structure. ASTER data and its indices showed good capability to estimate crown area in this study.

  20. Ectomycorrhizal Community Structure and Soil Characteristics of Mature Lodgepole Pine (Pinus Contorta) and Adjacent Stands of Old Growth Mixed Conifer in Yellowstone National Park, Wyoming USA

    NASA Technical Reports Server (NTRS)

    Douglas, Robert B.; Parker, V. Thomas; Cullings, Kenneth W.; Sun, Sidney (Technical Monitor)

    2003-01-01

    Forest development patterns following disturbance are known to influence the physical and chemical attributes of soils at different points in time. Changes in soil resources are thought to have a corresponding effect on ectomycorrhizal (ECM) community structure. We used molecular methods to compare below-ground ECM species richness, composition, and abundance between adjacent stands of homogenous lodgepole pine and old growth mixed conifer in Yellowstone National Park (YNP). In each stand-type we collected soil cores to both identify mycorrhizae and assess soil chemistry. Although no statistical difference was observed in the mean number of ECM root tips per core between stand types, the total number of species identified (85 versus 35) and the mean number of species per core (8.8 +/- 0.6 versus 2.5 +/- 0.3) were significantly higher in lodgepole pine. Differences between the actual and estimated species richness levels indicated that these forest types support a high number of ECM species and that undersampling was severe. Species compositions were widely disparate between stands where only four species were shared out of a total of 116. Soil analysis also revealed that mixed conifer was significantly lower in pH, but higher in organic matter, potassium, phosphorus, and ammonium when compared to lodgepole pine stands. Species richness per core was correlated with these chemical data, however, analysis of covariance indicated that stand type was the only statistically significant factor in the observed difference in species richness. Our data suggest that ECM fungal richness increases as homogenous lodgepole pine stands grow and mature, but declines after Engelmann spruce and subalpine fir colonize. Despite difficulties linking species composition with soil chemistry, there are a variety of physical and chemical factors that could be influencing ECM community structure. Future field experiments are necessary to test some of the mechanisms potentially operating

  1. [Soil quality assessment of forest stand in different plantation esosystems].

    PubMed

    Huang, Yu; Wang, Silong; Feng, Zongwei; Gao, Hong; Wang, Qingkui; Hu, Yalin; Yan, Shaokui

    2004-12-01

    After a clear-cutting of the first generation Cunninghamia lanceolata plantation in 1982, three plantation ecosystems, pure Michelia macclurei stand (PMS), pure Chinese-fir stand (PCS) and their mixed stand, were established in spring 1983, and their effects on soil characteristics were evaluated by measuring some soil physical, chemical, microbiological and biochemical parameters. After 20 years' plantation, all test indices showed differences among different forest management models. Both PMS and MCM had a favorable effect on soil fertility maintenance. Soil quality assessment showed that some soil functions, e.g., water availability, nutrient availability, root suitability and soil quality index were all in a moderate level under the mixed and pure PMS stands, whereas in a relatively lower level under successive PCS stand. The results also showed that there existed close correlations between soil total organic C (TOC), cation exchange capacity (CEC), microbial biomass-C (Cmic) and other soil physical, chemical and biological indices. Therefore, TOC, CEC and Cmic could be used as the indicators in assessing soil quality in this study area. In addition, there were also positive correlations between soil microbial biomass-C and TOC, soil microbial biomass-N and total N, and soil microbial biomass-P and total P in the present study. PMID:15825426

  2. Contrasting rainfall generated debris flows from adjacent watersheds at Forest Falls, southern California, USA

    NASA Astrophysics Data System (ADS)

    Morton, Douglas M.; Alvarez, Rachel M.; Ruppert, Kelly R.; Goforth, Brett

    2008-04-01

    Debris flows are widespread and common in many steeply sloping areas of southern California. The San Bernardino Mountains community of Forest Falls is probably subject to the most frequently documented debris flows in southern California. Debris flows at Forest Falls are generated during short-duration high-intensity rains that mobilize surface material. Except for debris flows on two consecutive days in November 1965, all the documented historic debris flows have occurred during high-intensity summer rainfall, locally referred to as 'monsoon' or 'cloudburst' rains. Velocities of the moving debris range from about 5 km/h to about 90 km/h. Velocity of a moving flow appears to be essentially a function of the water content of the flow. Low velocity debris flows are characterized by steep snouts that, when stopped, have only small amounts of water draining from the flow. In marked contrast are high-velocity debris flows whose deposits more resemble fluvial deposits. In the Forest Falls area two adjacent drainage basins, Snow Creek and Rattlesnake Creek, have considerably different histories of debris flows. Snow Creek basin, with an area about three times as large as Rattlesnake Creek basin, has a well developed debris flow channel with broad levees. Most of the debris flows in Snow Creek have greater water content and attain higher velocities than those of Rattlesnake Creek. Most debris flows are in relative equilibrium with the geometry of the channel morphology. Exceptionally high-velocity flows, however, overshoot the channel walls at particularly tight channel curves. After overshooting the channel, the flows degrade the adjacent levee surface and remove trees and structures in the immediate path, before spreading out with decreasing velocity. As the velocity decreases the clasts in the debris flows pulverize the up-slope side of the trees and often imbed clasts in them. Debris flows in Rattlesnake Creek are relatively slow moving and commonly stop in the channel

  3. Contrasting rainfall generated debris flows from adjacent watersheds at Forest Falls, southern California, USA

    USGS Publications Warehouse

    Morton, D.M.; Alvarez, R.M.; Ruppert, K.R.; Goforth, B.

    2008-01-01

    Debris flows are widespread and common in many steeply sloping areas of southern California. The San Bernardino Mountains community of Forest Falls is probably subject to the most frequently documented debris flows in southern California. Debris flows at Forest Falls are generated during short-duration high-intensity rains that mobilize surface material. Except for debris flows on two consecutive days in November 1965, all the documented historic debris flows have occurred during high-intensity summer rainfall, locally referred to as 'monsoon' or 'cloudburst' rains. Velocities of the moving debris range from about 5??km/h to about 90??km/h. Velocity of a moving flow appears to be essentially a function of the water content of the flow. Low velocity debris flows are characterized by steep snouts that, when stopped, have only small amounts of water draining from the flow. In marked contrast are high-velocity debris flows whose deposits more resemble fluvial deposits. In the Forest Falls area two adjacent drainage basins, Snow Creek and Rattlesnake Creek, have considerably different histories of debris flows. Snow Creek basin, with an area about three times as large as Rattlesnake Creek basin, has a well developed debris flow channel with broad levees. Most of the debris flows in Snow Creek have greater water content and attain higher velocities than those of Rattlesnake Creek. Most debris flows are in relative equilibrium with the geometry of the channel morphology. Exceptionally high-velocity flows, however, overshoot the channel walls at particularly tight channel curves. After overshooting the channel, the flows degrade the adjacent levee surface and remove trees and structures in the immediate path, before spreading out with decreasing velocity. As the velocity decreases the clasts in the debris flows pulverize the up-slope side of the trees and often imbed clasts in them. Debris flows in Rattlesnake Creek are relatively slow moving and commonly stop in the

  4. Lidar remote sensing of forest canopy and stand structure

    NASA Astrophysics Data System (ADS)

    Lim, Kevin Sheng-Wei

    Passive optical and radar remote sensing have consistently failed to provide reliable estimates of biophysical properties describing canopy and stand structure, and consequently, have not met the data and information needs of forest, landscape, and global ecologists. Lidar remote sensing differs from all other remote sensing technologies in that it samples on a point-wise basis three-dimensional measurements of the surface of the earth and its features. As a result, lidar is capable of providing spatially explicit measurements of canopy height. The research presented in this thesis seeks to enhance our understanding of the application of airborne discrete return lidar for the estimation of canopy and stand structure. Here, the capability of lidar to measure tree height and estimate various biophysical properties describing canopy and stand structure in deciduous forests is investigated. The biophysical properties considered included maximum tree height, Lorey's mean tree height, mean diameter at breast height, total basal area, canopy openness, effective plant area index, crown closure, aboveground biomass and volume, and stem density. Three lidar metrics were considered for model development and applied successfully for estimating canopy and stand structure. Based on theories of plant allometry, a conceptual model is proposed that: (i) describes how vertical distributions of leaf area and lidar canopy height are related; and (ii) explains how certain lidar-based metrics are capable of estimating aboveground biomass. This model suggests that quantiles of lidar canopy height are equivalent with respect to predictive power, and that high sampling point densities are not required for estimating forest biophysical properties at the plot and stand level. To test this conceptual model, the following research issues are addressed in this thesis: (1) The equivalency of quantiles of lidar canopy height for estimation of aboveground biomass was examined for deciduous and

  5. Integrating forest-stand simulations with paleoecological records to examine long-term forest dynamics

    SciTech Connect

    Solomon, A.M.; Shugart, H.H.

    1983-01-01

    Computer models permit us to study the future dynamics of present-day forests. Before applying a simulation model to predict long-term behavior of a forest, the model output should be tested against appropriate forest data. A forest-stand simulation model (FORET) and one of its variants (FORWET) have been tested with time-parallel simulations in which climate variance was inferred directly from pollen chronologies (internal consistency) and from such independent sources as other pollen chronologies, regional periglacial geomorphology, and global climate model output (authenticity). Comparison of simulation output translated into inferred pollen, with actual pollen chronologies, confirmed the reliability and adequacy of the model for certain predictive tasks, e.g., estimating response of forest biomass storage to expected CO/sub 2/-induced warming. 82 references, 5 figures, 3 tables.

  6. Ectomycorrhiza succession patterns in Pinus sylvestris forests after stand-replacing fire in the Central Alps.

    PubMed

    Kipfer, Tabea; Moser, Barbara; Egli, Simon; Wohlgemuth, Thomas; Ghazoul, Jaboury

    2011-09-01

    Fires shape fundamental properties of many forest ecosystems and climate change will increase their relevance in regions where fires occur infrequently today. In ecosystems that are not adapted to fire, post-fire tree recruitment is often sparse, a fact that might be attributed to a transient lack of mycorrhizae. Ectomycorrhizal (EcM) fungi play an important role for recruitment by enhancing nutrient and water uptake of their hosts. The questions arise whether and for how long the EcM community is transformed by fire. We investigated the resistance and resilience of EcM fungal communities on a chronosequence of 12 Pinus sylvestris stands in Valais (Switzerland) and Val d'Aosta (Italy) affected by fire between 1990 and 2006. Soil samples from burnt and non-burnt forests were analyzed with respect to EcM fungi by means of a bioassay. The number of EcM species was significantly lower in samples from recently (2-5 years) burnt sites than non-burnt forest, and increased with time since fire reaching levels of adjacent forests after 15-18 years. Community composition changed after fire but did not converge to that of non-burnt sites over the 18 year period. Only Rhizopogon roseolus and Cenococcum geophilum were abundant in both burnt sites and adjacent forest. Our data indicate fire resistance of some EcM fungal species as well as rapid resilience in terms of species number, but not in species composition. As long as the function of different EcM species for seedling establishment is unknown, the consequences of long-term shifts in EcM community composition for tree recruitment remain unclear. PMID:21468664

  7. Forest stand structure from airborne polarimetric InSAR

    NASA Astrophysics Data System (ADS)

    Balzter, H.; Saich, P.; Luckman, A. J.; Skinner, L.; Grant, J.

    2002-01-01

    Interferometric SAR at short wavelengths can be used to retrieve stand height of forests. We evaluate the precision of tree height estimation from airborne single-pass interferometric E-SAR data at X-band VV polarisation and repeat-pass L-band polarimetric data. General yield class curves were used to estimate tree height from planting year, tree species and yield class data provided by the Forest Enterprise. The data were compared to tree height estimates from X-VV single-pass InSAR and repeat-pass polarimetric InSAR at L-band acquired by DLR's E-SAR during the SHAC campaign 2000. The effect of gap structure and incidence angle on retrieval precision of tree height from interferometric SAR is analysed. Appropriate correction methods to improve tree height retrieval are proposed. The coherent microwave model CASM is used with a Lindenmayer system tree model to simulate the observed underestimation of stand height in the presence of gaps.

  8. Distribution of radiocaesium in an Austrian forest stand.

    PubMed

    Strebl, F; Gerzabek, M H; Bossew, P; Kienzl, K

    1999-02-01

    Within an Austrian spruce stand, vertical distribution of radiocaesium in soil as well as 137Cs concentration in different forest ecosystem compartments including spruce and surface water were investigated 10 years after the Chernobyl accident. The total 137Cs inventory in the forest was estimated to be 46 kBq m-2 (ref. date: 86-05-01). From the collected data annual input rates via litterfall of 0.48% per year and output rates through waterflows of only 0.02% per year were derived. The results identify the high importance of forest soils as a sink for radiocaesium. The estimated ecological residence half-times turned out to be highest in the organic soil horizons (1-3 years per cm), whereas in mineral horizons the values decrease significantly. As a consequence, soil inventory represents more than 95% of the total, whereas only approximately 3.3% of the 137Cs inventory is stored in the living biomass of spruce trees and a further 0.5% in the phytomass of understorey vegetation. PMID:10077876

  9. 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

  10. Suggested stocking levels for forest stands in northeastern Oregon and southeastern Washington. Forest Service research note

    SciTech Connect

    Cochran, P.H.; Geist, J.M.; Clemens, D.L.; Clausnitzer, R.R.; Powell, D.C.

    1994-04-01

    Catastrophes and manipulation of stocking levels are primary determinants of stand development and the appearance of future forest landscapes. Managers need stocking level guides particularly for sites incapable of supporting stocking levels presented in normal yield tables. To take advantage of information currently available the authors used some assumptions to relate growth basal area (GBA) to stand density index (SDI) and then create stocking level curves for use in northeastern Oregon and southeastern Washington. Use of these curves cannot be expected to eliminate all insect and disease problems, but the impact of mountain pine beetle should be moderated.

  11. Mapping forest stand age in China using remotely sensed forest height and observation data

    NASA Astrophysics Data System (ADS)

    Zhang, Chunhua; Ju, Weimin; Chen, Jing M.; Li, Dengqiu; Wang, Xiqun; Fan, Wenyi; Li, Mingshi; Zan, Mei

    2014-06-01

    Forest stand age plays a crucial role in determining the terrestrial carbon source or sink strength and reflects major disturbance information. Forests in China have changed drastically in recent decades, but quantification of spatially explicit forest age at national level has been lacking to date. This study generated a national map of forest age at 1 km spatial resolution using the remotely sensed forest height and forest type data in 2005, as well as relationships between age and height retrieved from field observations. These relationships include biomass as an intermediate parameter for major forest types in different regions of China. Biomass-height and age-biomass relationships were well fitted using field observations, with respective R2 values greater than 0.60 and 0.71 (P < 0.01), indicating the viability of age-height relationships developed for age estimation in China. The resulting map was evaluated by comparison with national, provincial, and county forest inventories. The validation had high regional (R2 = 0.87, 2-8 years errors in six regions), provincial (R2 = 0.53, errors less than 10 years and consistent age structure in most provinces), and plot (R2 values of 0.16-0.32, P < 0.01) agreement between map values and inventory-based estimates. This confirms the reliability and applicability of the age-height approach demonstrated in this study for quantifying forest age over large regions. The map reveals a large spatial heterogeneity of forest age in China: old in southwestern, northwestern, and northeastern areas, and young in southern and eastern regions.

  12. Isotopic study of mercury sources and transfer between a freshwater lake and adjacent forest food web.

    PubMed

    Kwon, Sae Yun; Blum, Joel D; Nadelhoffer, Knute J; Timothy Dvonch, J; Tsui, Martin Tsz-Ki

    2015-11-01

    Studies of monomethylmercury (MMHg) sources and biogeochemical pathways have been extensive in aquatic ecosystems, but limited in forest ecosystems. Increasing evidence suggests that there is significant mercury (Hg) exchange between aquatic and forest ecosystems. We use Hg stable isotope ratios (δ(202)Hg and Δ(199)Hg) to investigate the relative importance of MMHg sources and assess Hg transfer pathways between Douglas Lake and adjacent forests located at the University of Michigan Biological Station, USA. We characterize Hg isotopic compositions of basal resources and use linear regression of % MMHg versus δ(202)Hg and Δ(199)Hg to estimate Hg isotope values for inorganic mercury (IHg) and MMHg in the aquatic and adjacent forest food webs. In the aquatic ecosystem, we found that lake sediment represents a mixture of IHg pools deposited via watershed runoff and precipitation. The δ(202)Hg and Δ(199)Hg values estimated for IHg are consistent with other studies that measured forest floor in temperate forests. The Δ(199)Hg value estimated for MMHg in the aquatic food web indicates that MMHg is subjected to ~20% photochemical degradation prior to bioaccumulation. In the forest ecosystem, we found a significant negative relationship between total Hg and δ(202)Hg and Δ(199)Hg of soil collected at multiple distances from the lakeshore and lake sediment. This suggests that IHg input from watershed runoff provides an important Hg transfer pathway between the forest and aquatic ecosystems. We measured Δ(199)Hg values for high trophic level insects and compared these insects at multiple distances perpendicular to the lake shoreline. The Δ(199)Hg values correspond to the % canopy cover suggesting that forest MMHg is subjected to varying extents of photochemical degradation and the extent may be controlled by sunlight. Our study demonstrates that the use of Hg isotopes adds important new insight into the relative importance of MMHg sources and complex Hg transfer

  13. Simulating stand climate, phenology, and photosynthesis of a forest stand with a process-based growth model

    NASA Astrophysics Data System (ADS)

    Rötzer, Thomas; Leuchner, Michael; Nunn, Angela J.

    2010-07-01

    In the face of climate change and accompanying risks, forest management in Europe is becoming increasingly important. Model simulations can help to understand the reactions and feedbacks of a changing environment on tree growth. In order to simulate forest growth based on future climate change scenarios, we tested the basic processes underlying the growth model BALANCE, simulating stand climate (air temperature, photosynthetically active radiation (PAR) and precipitation), tree phenology, and photosynthesis. A mixed stand of 53- to 60-year-old Norway spruce ( Picea abies) and European beech ( Fagus sylvatica) in Southern Germany was used as a reference. The results show that BALANCE is able to realistically simulate air temperature gradients in a forest stand using air temperature measurements above the canopy and PAR regimes at different heights for single trees inside the canopy. Interception as a central variable for water balance of a forest stand was also estimated. Tree phenology, i.e. bud burst and leaf coloring, could be reproduced convincingly. Simulated photosynthesis rates were in accordance with measured values for beech both in the sun and the shade crown. For spruce, however, some discrepancies in the rates were obvious, probably due to changed environmental conditions after bud break. Overall, BALANCE has shown to respond to scenario simulations of a changing environment (e.g., climate change, change of forest stand structure).

  14. Simulating stand climate, phenology, and photosynthesis of a forest stand with a process-based growth model.

    PubMed

    Rötzer, Thomas; Leuchner, Michael; Nunn, Angela J

    2010-07-01

    In the face of climate change and accompanying risks, forest management in Europe is becoming increasingly important. Model simulations can help to understand the reactions and feedbacks of a changing environment on tree growth. In order to simulate forest growth based on future climate change scenarios, we tested the basic processes underlying the growth model BALANCE, simulating stand climate (air temperature, photosynthetically active radiation (PAR) and precipitation), tree phenology, and photosynthesis. A mixed stand of 53- to 60-year-old Norway spruce (Picea abies) and European beech (Fagus sylvatica) in Southern Germany was used as a reference. The results show that BALANCE is able to realistically simulate air temperature gradients in a forest stand using air temperature measurements above the canopy and PAR regimes at different heights for single trees inside the canopy. Interception as a central variable for water balance of a forest stand was also estimated. Tree phenology, i.e. bud burst and leaf coloring, could be reproduced convincingly. Simulated photosynthesis rates were in accordance with measured values for beech both in the sun and the shade crown. For spruce, however, some discrepancies in the rates were obvious, probably due to changed environmental conditions after bud break. Overall, BALANCE has shown to respond to scenario simulations of a changing environment (e.g., climate change, change of forest stand structure). PMID:20084520

  15. The impact of disturbance and ensuing forestry practices on Collembola in spruce forest stands

    NASA Astrophysics Data System (ADS)

    Čuchta, Peter

    2016-04-01

    Soil Collembola communities were investigated in spruce forest stands of the High Tatra Mts that had been heavily damaged by a windstorm in November 2004 and subsequently by a wildfire in July 2005. The study focused on the impact of these disturbances and forestry practices on collembolan community distribution and structure four years after the disturbance. Four different treatments were selected for this study: intact forest stands (REF), non-extracted windthrown stands (NEX), clear-cut windthrown stands (EXT) and burnt windthrown stands (FIR). From a total of 7,820 individuals, 72 species were identified. The highest total abundance mean was recorded in FIR stands followed by NEX and EXT stands and, surprisingly, the lowest in REF stands. The highest total species richness was observed in REF stands, followed by NEX stands and FIR stands and the lowest in EXT stands. In REF and NEX stands the most abundant species were Folsomia penicula and Tetracanthella fjellbergi, while in heavily damaged stands the most abundant was Anurophorus laricis. The present study shows the negative impact of windthrow on Collembola communities as reflected in decreased species richness and abundance. However, disturbance by fire caused a considerable increase in collembolan abundance three years after the event. Moreover, we found out that clearing of windthrown spruce forests after a windstorm is less favourable for communities of soil collembolans and slows down the recovery process.

  16. Parametric analysis of synthetic aperture radar data for the study of forest stand characteristics

    NASA Technical Reports Server (NTRS)

    Wu, Shih-Tseng

    1988-01-01

    A parametric analysis of a Gulf Coast forest stand was performed using multipolarization, multipath airborne SAR data, and forest plot properties. Allometric equations were used to compute the biomass and basal area for the test plots. A multiple regression analysis with stepwise selection of independent variables was performed. It is found that forest stand characteristics such as biomass, basal area, and average tree height are correlated with SAR data.

  17. Potential change in forest types and stand heights in central Siberia in a warming climate

    NASA Astrophysics Data System (ADS)

    Tchebakova, N. M.; Parfenova, E. I.; Korets, M. A.; Conard, S. G.

    2016-03-01

    Previous regional studies in Siberia have demonstrated climate warming and associated changes in distribution of vegetation and forest types, starting at the end of the 20th century. In this study we used two regional bioclimatic envelope models to simulate potential changes in forest types distribution and developed new regression models to simulate changes in stand height in tablelands and southern mountains of central Siberia under warming 21st century climate. Stand height models were based on forest inventory data (2850 plots). The forest type and stand height maps were superimposed to identify how heights would change in different forest types in future climates. Climate projections from the general circulation model Hadley HadCM3 for emission scenarios B1 and A2 for 2080s were paired with the regional bioclimatic models. Under the harsh A2 scenario, simulated changes included: a 80%-90% decrease in forest-tundra and tundra, a 30% decrease in forest area, a ˜400% increase in forest-steppe, and a 2200% increase in steppe, forest-steppe and steppe would cover 55% of central Siberia. Under sufficiently moist conditions, the southern and middle taiga were simulated to benefit from 21st century climate warming. Habitats suitable for highly-productive forests (≥30-40 m stand height) were simulated to increase at the expense of less productive forests (10-20 m). In response to the more extreme A2 climate the area of these highly-productive forests would increase 10%-25%. Stand height increases of 10 m were simulated over 35%-50% of the current forest area in central Siberia. In the extremely warm A2 climate scenario, the tall trees (25-30 m) would occur over 8%-12% of area in all forest types except forest-tundra by the end of the century. In forest-steppe, trees of 30-40 m may cover some 15% of the area under sufficient moisture.

  18. Soil Carbon Storage and Turnover in an Old-Growth Coastal Redwood Forest and Adjacent Prairie

    NASA Astrophysics Data System (ADS)

    McFarlane, K. J.; Torn, M. S.; Mambelli, S.; Dawson, T. E.

    2010-12-01

    Coastal redwood (Sequoia sempervirens) forests store lots of carbon in aboveground tree biomass because redwoods are very long-lived and can grow very large. Redwood is known for its high resistance to decay, a result of high levels of aromatic compounds (tannins) in the tree’s tissues. We tested the hypothesis that because coastal redwoods are highly productive and produce organic matter that is chemically resistant to decay, old-growth redwood forests should store large amounts of stabilized soil carbon. We measured soil C storage to 110 cm depth in an old-growth coastal redwood forest and used physical soil fractionation combined with radiocarbon measurements to determine soil organic matter turnover time. In addition, we measured soil C storage and turnover at an adjacent prairie experiencing the same climate and with soils derived from the same parent material. We found larger soil C stocks to 110 cm at the prairie (350 Mg C ha-1) than the redwood forest (277 Mg C ha-1) even with O-horizons included for the forest. Larger N stocks were also observed at the prairie than the redwood and these differences in stocks were driven by higher C and N concentrations in mineral soils at the prairie. Differences between ecosystems in soil C and N concentrations, C:N ratios, and C and N stocks were observed for the top 50 cm only, suggesting that the influence of the different litter types did not extend to deeper soils. Contrary to what was expected, bulk soil and heavy density-fraction Δ14C values were higher, indicating shorter turnover times, for the redwood forest than the prairie. In summary, we did not observe greater C storage or 14C-based turnover times in old-growth redwood forest compared to adjacent prairie, suggesting chemical recalcitrance of litter inputs does not drive soil C stabilization at these ecosystems.

  19. Forest stand growth dynamics in Central Europe have accelerated since 1870

    PubMed Central

    Pretzsch, Hans; Biber, Peter; Schütze, Gerhard; Uhl, Enno; Rötzer, Thomas

    2014-01-01

    Forest ecosystems have been exposed to climate change for more than 100 years, whereas the consequences on forest growth remain elusive. Based on the oldest existing experimental forest plots in Central Europe, we show that, currently, the dominant tree species Norway spruce and European beech exhibit significantly faster tree growth (+32 to 77%), stand volume growth (+10 to 30%) and standing stock accumulation (+6 to 7%) than in 1960. Stands still follow similar general allometric rules, but proceed more rapidly through usual trajectories. As forest stands develop faster, tree numbers are currently 17–20% lower than in past same-aged stands. Self-thinning lines remain constant, while growth rates increase indicating the stock of resources have not changed, while growth velocity and turnover have altered. Statistical analyses of the experimental plots, and application of an ecophysiological model, suggest that mainly the rise in temperature and extended growing seasons contribute to increased growth acceleration, particularly on fertile sites. PMID:25216297

  20. Effects of Sloped Terrain and Forest Stand Maturity on Evapotranspiration in a Boreal Forested Catchment

    NASA Astrophysics Data System (ADS)

    Isabelle, P. E.; Nadeau, D.; Parent, A. C.; Rousseau, A. N.; Jutras, S.; Anctil, F.

    2015-12-01

    The boreal forests are the predominant landscape of Canada, occupying 49% of its boreal zone or 27% of the country. Despite the tremendous amount of literature on such ecosystems, some gaps persist in our understanding of boreal forest evapotranspiration (ET), given that direct measurements are costly to obtain and therefore scarce in these remote territories. This is especially the case on sloped terrain, since the eddy covariance method is not traditionally used in such situations. These gaps lead to the implementation of the EVAP experimental project, which intends to produce a major leap in our understanding of the water and energy budgets of a sloped boreal forest. Starting in summer 2015, we heavily instrumented a watershed in the Montmorency Forest (47°17' N; 71°10' W), Quebec, Canada. Located in the Laurentian Mountains, the forest has a mean elevation of 750 m with peaks at 1000 m. The setup includes a 20-m flux tower with two separate sets of eddy correlation and net radiation measurements facing opposite directions, located over an almost mature boreal forest (logged ~20 years ago, 8-10 m trees). Eddy fluxes are also measured under the canopy with a similar setup, while a sub-watershed is instrumented with a 10-m flux tower using homologous instruments, this time on a much younger forest stand (logged ~10 years ago, 4-5 m trees). Both sites are characterized by a significant slope (~20%), facing northeast for the 20-m tower and west for the 10-m tower. With several other instruments, we are measuring every major components of both water and energy budgets, including the outgoing discharge of the watershed and subwatershed. The different slope orientations and local topography of both sites allow us to quantify the relationships between solar exposition, topographic shading and ET rates; these relationships being transposable to other mountainous forested catchments. We also investigate the presence of slope flows and assess their impact on local ET

  1. Stochastically generating tree diameter lists to populate forest stands based on the linkage variables, forest type and stand age.

    SciTech Connect

    Parresol, B.R.; Lloyd, F.T.

    2003-08-31

    Forest inventory data were used to develop a stand-age-driven, stochastic predictor of unit-area, frequency-weighted lists of breast high tree diameters (DBH). The average of mean statistics from 40-simulation prediction sets of an independent 78-plot validation dataset differed from the observed validation means by 0.5 cm for DBH, and by 12 trees/h for density. The 40-simulation average of standard deviation, quartile range, maximum value and minimum value differed from the validation dataset, respectively, by 0.3, 1.3, 0.6 and 1.5 cm for DBH, and 10, 42, 29, and 54 trees/h for density. In addition, test statistics were also computed individually for each of the 40 single simulations of the 78-plot validation dataset. In all cases, the test statistics supported the null hypothesis of no difference between simulated and observed DBH lists. When power of these hypothesis test statistics was set to 80%, the calculated minimum detectable differences were still reasonably small at 2.7 cm for mean DBH and 90 trees/h for stocking. Also, the shape and dispersion of simulated mean-DBH/density scatter graphs were similar to the same scatter graph from the observed, validation dataset.

  2. Standing stock of deep-sea metazoan meiofauna in the Sulu Sea and adjacent areas

    NASA Astrophysics Data System (ADS)

    Shimanaga, Motohiro; Nomaki, Hidetaka; Suetsugu, Kishiko; Murayama, Masafumi; Kitazato, Hiroshi

    2007-01-01

    Standing stocks of deep-sea metazoan meiofauna were investigated in the Sulu Sea, one of the most isolated marginal basins with comparably warm bottom-water temperatures (˜10 °C) at depths below 1000 m. A decline in the abundance and biomass of organisms with increasing water depth occurred in the basin, but the abundances at bathyal and abyssal sites in the Sulu Basin appeared to be lower than standard values worldwide when adjusted for water depth. There is no significant correlation between meiofaunal abundance and the concentration of chloroplastic pigment equivalents (CPE) in the sediment, an indicator of the amount of organic matter derived from primary production. The ratios of meiofaunal abundance to CPE concentration at the sampling sites were as small as those observed at comparable depths in the Red Sea. These suggest that the quantity of "food" is not a primary factor limiting the density of organisms in the basin. It is hypothesized that a higher respiratory activity of benthos caused by warm bottom water and a lower food quality could be important factors regulating the metazoan meiofaunal standing stocks in the Sulu Sea.

  3. 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

  4. 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.

  5. Application of Lidar remote sensing to the estimation of forest canopy and stand structure

    NASA Astrophysics Data System (ADS)

    Lefsky, Michael Andrew

    A new remote sensing instrument, SLICER (Scanning Lidar Imager of Canopies by Echo Recovery), has been applied to the problem of remote sensing the canopy and stand structure of two groups of deciduous forests, Tulip Poplar-Oak stands in the vicinity of Annapolis, MD. and bottomland hardwood stands near Williamston, NC. The ability of the SLICER instrument to remotely sense the vertical distribution of canopy structure (Canopy Height Profile), bulk canopy transmittance, and several indices of canopy height has been successfully validated using twelve stands with coincident field and SLICER estimates of canopy structure. Principal components analysis has been applied to canopy height profiles from both field sites, and three significant factors were identified, each closely related to the amount of foliage in a recognizable layer of the forest, either understory, midstory, or overstory. The distribution of canopy structure to these layers is significantly correlated with the size and number of stems supporting them. The same layered structure was shown to apply to both field and SLICER remotely sensed canopy height profiles, and to apply to SLICER remotely sensed canopy profiles from both the bottomland hardwood stands in the coastal plain of North Carolina, and to mesic Tulip-Poplars stands in the upland coastal plain of Maryland. Linear regressions have demonstrated that canopy and stand structure are correlated to both a statistically significant and useful degree. Stand age and stem density is more highly correlated to stand height, while stand basal area and aboveground biomass are more closely related to a new measure of canopy structure, the quadratic mean canopy height. A geometric model of canopy structure has been shown to explain the differing relationships between canopy structure and stand basal area for stands of Eastern Deciduous Forest and Douglas Fir Forest.

  6. Canopy transpiration of pure and mixed forest stands with variable abundance of European beech

    NASA Astrophysics Data System (ADS)

    Gebauer, Tobias; Horna, Viviana; Leuschner, Christoph

    2012-06-01

    SummaryThe importance of tree species identity and diversity for biogeochemical cycles in forests is not well understood. In the past, forestry has widely converted mixed forests to pure stands while contemporary forest policy often prefers mixed stands again. However, the hydrological consequences of these changes remain unclear. We tested the hypotheses (i) that significant differences in water use per ground area exist among the tree species of temperate mixed forests and that these differences are more relevant for the amount of stand-level canopy transpiration (Ec) than putative complementarity effects of tree water use, and (ii) that the seasonal patterns of Ec in mixed stands are significantly influenced by the identity of the present tree species. We measured xylem sap flux during 2005 (average precipitation) and 2006 (relatively dry) synchronously in three nearby old-growth forest stands on similar soil differing in the abundance of European beech (pure beech stand, 3-species stand with 70% beech, 5-species stand with <10% beech). In summer 2005 with average rainfall, Ec was 50% higher in the beech-poor 5-species stand than in the two stands with moderate to high beech presence (158 vs. 97 and 101 mm yr-1); in the dry summer 2006, all stands converged toward similar Ec totals (128-139 mm yr-1). Species differences in Ec were large on a sapwood area basis, reflecting a considerable variation in hydraulic architecture and leaf conductance regulation among the co-existing species. Moreover, transpiration per crown projection area (ECA) also differed up to 5-fold among the different species in the mixed stands, probably reflecting contrasting sapwood/crown area ratios. We conclude that Ec is not principally higher in mixed forests than in pure beech stands. However, tree species-specific traits have an important influence on the height of Ec and affect its seasonal variation. Species with a relatively high ECA (notably Tilia) may exhaust soil water reserves

  7. Mapping post-disturbance stand age distribution in Siberian larch forest based on a novel method

    NASA Astrophysics Data System (ADS)

    Chen, D.; Loboda, T. V.; Krylov, A.; Potapov, P.

    2014-12-01

    The Siberian larch forest, which accounts for nearly 20% of the global boreal forest biome, is unique, important, yet significantly understudied. These deciduous needleleaf forests with a single species dominance over a large continuous area are not found anywhere except the extreme continental zones of Siberia and the Russian Far East. Most of these forests are located in remote and sparsely populated areas and, therefore, little is known about spatial variability of their structure and dynamics. Wall-to-wall repeated observations of this area are available only since the 2000s. Previously, we developed methods for reconstruction of stand-age distribution from a sample of 1980-2000 disturbances in Landsat TM and ETM+ imagery. However, availability of those images in Siberian larch forests is particularly limited. Built upon the hypothesis that the spectral characteristics of the disturbed forest in the region change with time consistently, this paper proposes a novel method utilizing the newly released Global Forest Change (GFC) 2000-2012 dataset. We exploit the data-rich era of annual forest disturbance samples identified between 2000 and 2012 in the Siberian larch forest by the GFC dataset to build a robust training set of spectral signatures from regrowing larch forests as they appear in Landsat imagery in 2012. The extracted statistics are ingested into a random forest, which predicts the approximate stand age for every forested pixel in the circa 2000 composite. After merging the estimated stand age distribution for 1989-2000 with the observed disturbance records for 2001-2012, a gap-free 30 m resolution 24-year long record of stand age distribution is obtained. A preliminary accuracy assessment against the Advanced Very High Resolution Radiometer (AVHRR) burned area product suggested satisfactory performance of the proposed method.

  8. Estimating structural attributes of Douglas-fir/western hemlock forest stands from Landsat and SPOT imagery

    NASA Technical Reports Server (NTRS)

    Cohen, Warren B.; Spies, Thomas A.

    1992-01-01

    Relationships between spectral and texture variables derived from SPOT HRV 10 m panchromatic and Landsat TM 30 m multispectral data and 16 forest stand structural attributes is evaluated to determine the utility of satellite data for analysis of hemlock forests west of the Cascade Mountains crest in Oregon and Washington, USA. Texture of the HRV data was found to be strongly related to many of the stand attributes evaluated, whereas TM texture was weakly related to all attributes. Data analysis based on regression models indicates that both TM and HRV imagery should yield equally accurate estimates of forest age class and stand structure. It is concluded that the satellite data are a valuable source for estimation of the standard deviation of tree sizes, mean size and density of trees in the upper canopy layers, a structural complexity index, and stand age.

  9. Influence of forest input data on rockfall simulations at the stand level

    NASA Astrophysics Data System (ADS)

    Monnet, Jean-Matthieu; Bourrier, Franck; Toe, David

    2014-05-01

    The protective effect of trees against rockfall hazards has been known for a long time and numerical models are now able to simulate the trajectory of falling rocks and the possibility of impacts with trees. Using such models in real case-study requires high resolution input data regarding topography and forest cover, such as provided by airborne laser scanning (ALS) remote sensing. However, the errors in forest predictions might result in erroneous forest protection quantification. The objective here is to compare the results of rockfall simulations within a forest stand whose characteristics are derived from two types of data: field inventory or ALS remote sensing. The software RockyFor3D is used to simulate the propagation of 2 m3 blocks on a 35° slope. Blocks accelerate across an unforested area of 50 m and then enter a forest stand where impacts on trees might slow or stop them. The kinetic energy of passing blocks is recorded at the contour line immediately below the forest patch. Two forest stands are used to produce the input data for the forest patch : a high forest (80x120m2) and a coppice forest (50x50m2). For each stand, five scenarios for forest data inputs are compared. - 'real': the tree positions and diameters inventoried on the field are used. - 'inventory': stand-level parameters derived from the 'real' inventory are supplied to the software which will then simulates the positions. - 'stand estimation': stand-level parameters derived from the ALS data are supplied. - 'tree detection': tree positions and diameters are estimated from the ALS data. For the coppice stand, the 'real' and 'inventory' scenarios yield similar results: approx. 82% of passing blocks with a mean energy of 360 kJ. The small difference may come from the models used to generate trees positions and diameters from the stand-level data. In the 'stand estimation' scenario almost all blocks pass through the forest (98%) and they have higher energies (390 kJ). The forest protection

  10. Agricultural Intensification Exacerbates Spillover Effects on Soil Biogeochemistry in Adjacent Forest Remnants

    PubMed Central

    Didham, Raphael K.; Barker, Gary M.; Bartlam, Scott; Deakin, Elizabeth L.; Denmead, Lisa H.; Fisk, Louise M.; Peters, Jennifer M. R.; Tylianakis, Jason M.; Wright, Hannah R.; Schipper, Louis A.

    2015-01-01

    Land-use intensification is a central element in proposed strategies to address global food security. One rationale for accepting the negative consequences of land-use intensification for farmland biodiversity is that it could ‘spare’ further expansion of agriculture into remaining natural habitats. However, in many regions of the world the only natural habitats that can be spared are fragments within landscapes dominated by agriculture. Therefore, land-sparing arguments hinge on land-use intensification having low spillover effects into adjacent protected areas, otherwise net conservation gains will diminish with increasing intensification. We test, for the first time, whether the degree of spillover from farmland into adjacent natural habitats scales in magnitude with increasing land-use intensity. We identified a continuous land-use intensity gradient across pastoral farming systems in New Zealand (based on 13 components of farmer input and soil biogeochemistry variables), and measured cumulative off-site spillover effects of fertilisers and livestock on soil biogeochemistry in 21 adjacent forest remnants. Ten of 11 measured soil properties differed significantly between remnants and intact-forest reference sites, for both fenced and unfenced remnants, at both edge and interior. For seven variables, the magnitude of effects scaled significantly with magnitude of surrounding land-use intensity, through complex interactions with fencing and edge effects. In particular, total C, total N, δ15N, total P and heavy-metal contaminants of phosphate fertilizers (Cd and U) increased significantly within remnants in response to increasing land-use intensity, and these effects were exacerbated in unfenced relative to fenced remnants. This suggests movement of livestock into surrounding natural habitats is a significant component of agricultural spillover, but pervasive changes in soil biogeochemistry still occur through nutrient spillover channels alone, even in fenced

  11. Correspondence of ectomycorrhizal diversity and colonisation of willows (Salix spp.) grown in short rotation coppice on arable sites and adjacent natural stands.

    PubMed

    Hrynkiewicz, Katarzyna; Toljander, Ylva K; Baum, Christel; Fransson, Petra M A; Taylor, Andy F S; Weih, Martin

    2012-11-01

    Willows (Salix spp.) are mycorrhizal tree species sometimes cultivated as short rotation coppice (SRC) on arable sites for energy purposes; they are also among the earliest plants colonising primary successional sites in natural stands. The objective of this study was to analyse the degree of colonisation and diversity of ectomycorrhizal (EM) communities on willows grown as SRC in arable soils and their adjacent natural or naturalized stands. Arable sites usually lack ectomycorrhizal host plants before the establishment of SRC, and adjacent natural or naturalized willow stands were hypothesized to be a leading source of ectomycorrhizal inoculum for the SRC. Three test sites including SRC stands (Salix viminalis, Salix dasyclados, and Salix schwerinii) and adjacent natural or naturalized (Salix caprea, Salix fragilis, and Salix × mollissima) stands in central Sweden were investigated on EM colonisation and morphotypes, and the fungal partners of 36 of the total 49 EM fungi morphotypes were identified using molecular tools. The frequency of mycorrhizas in the natural/naturalized stands was higher (two sites) or lower (one site) than in the corresponding cultivated stands. Correspondence analysis revealed that some EM taxa (e.g. Agaricales) were mostly associated with cultivated willows, while others (e.g. Thelephorales) were mostly found in natural/naturalized stands. In conclusion, we found strong effects of sites and willow genotype on EM fungi formation, but poor correspondence between the EM fungi abundance and diversity in SRC and their adjacent natural/naturalized stands. The underlying mechanism might be selective promotion of some EM fungi species by more effective spore dispersal. PMID:22415721

  12. Variation in Carbon Storage and Its Distribution by Stand Age and Forest Type in Boreal and Temperate Forests in Northeastern China

    PubMed Central

    Wei, Yawei; Li, Maihe; Chen, Hua; Lewis, Bernard J.; Yu, Dapao; Zhou, Li; Zhou, Wangming; Fang, Xiangmin; Zhao, Wei; Dai, Limin

    2013-01-01

    The northeastern forest region of China is an important component of total temperate and boreal forests in the northern hemisphere. But how carbon (C) pool size and distribution varies among tree, understory, forest floor and soil components, and across stand ages remains unclear. To address this knowledge gap, we selected three major temperate and two major boreal forest types in northeastern (NE) China. Within both forest zones, we focused on four stand age classes (young, mid-aged, mature and over-mature). Results showed that total C storage was greater in temperate than in boreal forests, and greater in older than in younger stands. Tree biomass C was the main C component, and its contribution to the total forest C storage increased with increasing stand age. It ranged from 27.7% in young to 62.8% in over-mature stands in boreal forests and from 26.5% in young to 72.8% in over-mature stands in temperate forests. Results from both forest zones thus confirm the large biomass C storage capacity of old-growth forests. Tree biomass C was influenced by forest zone, stand age, and forest type. Soil C contribution to total forest C storage ranged from 62.5% in young to 30.1% in over-mature stands in boreal and from 70.1% in young to 26.0% in over-mature in temperate forests. Thus soil C storage is a major C pool in forests of NE China. On the other hand, understory and forest floor C jointly contained less than 13% and <5%, in boreal and temperate forests respectively, and thus play a minor role in total forest C storage in NE China. PMID:23977252

  13. Kelp forest fish populations in marine reserves and adjacent exploited areas of central California

    USGS Publications Warehouse

    Paddack, M.J.; Estes, J.A.

    2000-01-01

    Population structure (density and size distribution) of 10 species of epibenthic kelp forest fishes was compared between three marine reserves and adjacent exploited areas in central California. We also contrasted substrate relief, algal turf cover, and kelp population density among these areas. Densities of fishes were 12-35% greater within the reserves, but this difference was not statistically) significant. Habitat features explained only 4% of the variation in fish density and did not vary consistently between reserves and nonreserves. The average length of rockfish (genus Sebastes) was significantly greater in two of the three reserve sites, as was the proportion of larger fish. Population density and size differences combined to produce substantially greater biomass and, therefore, greater reproductive potential per unit of area within the reserves. The magnitude of these effects seems to be influenced by the reserve's age. Our findings demonstrate that current levels of fishing pressure influence kelp forest rockfish populations and suggest that this effect is widespread in central California. Existing marine reserves in central California kelp forests may help sustain exploited populations both through adult emigration and larval pool augmentation. The magnitude of these effects remains uncertain, however, because the spatial scale of both larval and adult dispersal relative to the size of existing reserves is unknown.

  14. Significant Emissions of Methane and Nitrous Oxide Following Clear-cutting of a Boreal Forest Stand

    NASA Astrophysics Data System (ADS)

    Vestin, P.; Mölder, M.; Sundqvist, E.; Hellström, M.; Båth, A.; Klemedtsson, L. K.; Lindroth, A.

    2011-12-01

    Clear-cutting and subsequent site preparation is common forest management practice in Sweden. According to the Swedish National Forest Inventory, an average of 196 000 ha were clear-cut annually during the period 2005-2009. The net effects of final fellings on greenhouse gas fluxes are not well understood. Increased substrate availability for decomposers following harvest may result in higher carbon dioxide (CO2) emissions from soils and in increased nitrogen mineralization. This may be further enhanced by increased soil temperatures after site preparation. In addition, removal of trees causes reduced evapotranspiration and subsequently a raised ground water table, which may have consequences for methane (CH4) and nitrous oxide (N2O) fluxes. The net effects of clear-cutting on CH4, N2O, CO2 and H2O fluxes were studied at Norunda forest in central Sweden. Micrometeorological measurements (i.e. flux-gradient and eddy covariance) allowed for quantification of CO2, CH4, N2O and H2O fluxes at two different plots on a new clear-cut. Measurements of CH4, CO2 and H2O fluxes started in May 2010 while N2O flux measurements begun in June 2011. Soil chamber measurements (CO2, CH4 and H2O) were carried out in the adjacent forest stand during the main growing season of 2010 and at the clear-cut during October-November 2010. The clear-cut became waterlogged after harvest (more pronounced at plot 1) and preliminary results indicate a switch from a weak CH4 sink to a significant CH4 source at both plots. Daily average fluxes during the period 20 May through 30 November 2010 were of the order of -6.3 - +142.5 μmol m-2h-1 (Fig.1) with mean values of 39.0 μmol m-2h-1 (plot 1) and 16.3 μmol m-2h-1 (plot 2). The preliminary results also indicate enhanced CO2 emissions and increased soil temperatures at disturbed microsites. Raw N2O data imply N2O fluxes of the order of 1-10 μmol m-2h-1 during daytime (well-mixed) conditions. Available data, including 2011, will be further analyzed

  15. Effects of Stand age Structure on Regional Carbon Budgets of Forest Ecosystems

    NASA Astrophysics Data System (ADS)

    Song, C.; Woodcock, C. E.

    2002-12-01

    This study has developed a two-stage modeling scheme to investigate the importance of age structure on regional carbon fluxes for the forests in the Pacific Northwest of the United States. In the first stage, an individual-based forest ecosystem carbon flux model (IntCarb) at stand scale is developed. IntCarb combines components from the ZELIG and CENTURY models to simulate forest growth and development, and heterotrophic respiration, respectively. Stand scale carbon fluxes simulated by IntCarb strongly depend on stand age. Due to its high variablity over large areas, forest age structure has to be taken into account for realistic estimation of carbon budgets. The RegCarb model is developed to estimate regional scale carbon fluxes based on forest age structure and adjusting for the nonrespiratory carbon losses, such as harvesting. Our initial estimate with RegCarb for the Pacific Northwest of the United States found that this region was a tremendous carbon source to the atmosphere from 1890 to 1990 due to intensive logging of old-growth forest, and is becoming a carbon sink since the last decade. Projections for the role of forests in this region in the global carbon cycle in the future strongly depend on the amount of timber to be harvested, i.e. how the age structure of forests in this region is to be altered.

  16. Scaling Hydrologic Processes in Boreal Forest Stands: New Eco-hydrological Perspectives or Deja vu?

    NASA Astrophysics Data System (ADS)

    Silins, U.; Lieffers, V. J.; Landhausser, S. M.; Mendoza, C. A.; Devito, K. J.; Petrone, R. M.; Gan, T. Y.

    2006-12-01

    The leaf area of forest canopies is both main attribute of stands controlling water balance through transpiration and interception, and "engine" driving stand growth, stand dynamics, and forest succession. While transpiration and interception dynamics are classic themes in forest hydrology, we present results from our eco-hydrological research on boreal trees to highlight how more recent eco-physiological insights into species specific controls over water use and leaf area such as hydraulic architecture, cavitation, sapwood-leaf area relationships, and root system controls over water uptake are providing new insights into integrated atmospheric-autecological controls over these hydrologic processes. These results are discussed in the context of newer eco-hydrological frameworks which may serve to aid in exploring how forest disturbance and subsequent trajectories of hydrologic recovery are likely to affect both forest growth dynamics and hydrology of forested landscapes in response to forest management, severe forest pest epidemics such as the Mountain Pine Beetle epidemic in Western Canada, and climate change.

  17. Aspects of Boreal Forest Hydrology: From Stand to Watershed

    NASA Technical Reports Server (NTRS)

    Nijssen, B.

    2000-01-01

    This report evaluates land surface hydrologic processes in the boreal forest using observations collected during the Boreal Ecosystem Atmospheric Study (BOREAS), carried out in the boreal forest of central Canada from 1994 to 1996. Three separate studies, each of which constitutes a journal publication, are included. The first study describes the application of a spatially-distributed hydrologic model, originally developed for mid-latitude forested environments, to selected BOREAS flux measurement sites. Compared to point observations at the flux towers, the model represented energy and moisture fluxes reasonably well, but shortcomings were identified in the soil thermal submodel and the partitioning of evapotranspiration into canopy and subcanopy components. As a first step towards improving this partitioning, the second study develops a new parameterization for transmission of shortwave radiation through boreal forest canopies. The new model accounts for the transmission of diffuse and direct shortwave radiation and accounts for multiple scattering in the canopy and multiple reflections between the canopy layers.

  18. Taiga forest stands and SAR: Monitoring for subarctic global change

    SciTech Connect

    Way, J.; Kwok, R.; Viereck, L.; Slaughter, C.; Dobson, C.

    1992-03-01

    In preparation for the first European Earth Remote Sensing (ERS-1) mission, a series of multitemporal, multifrequency, multipolarization aircraft synthetic aperture radar (SAR) data sets were acquired over the Bonanza Creek Experimental Forest near Fairbanks, Alaska in March 1988. Significant change in radar backscatter was observed over the two-week experimental period due to changing environmental conditions. These preliminary results are presented to illustrate the opportunity afforded by the ERS-1 SAR to monitor temporal change in forest ecosystems.

  19. An investigation of observed phase differences between clearcut and standing forests in interferograms from the Pacific Northwest

    NASA Astrophysics Data System (ADS)

    Prush, V. B.; Lohman, R. B.

    2011-12-01

    clearcutting relative to the SAR acquisitions. This effect would also correlate with baseline, but also, potentially, with time. Soil moisture may also account for the observed difference in returned phase. Changes in soil moisture between areas where forests remain standing and where clearcutting has occurred may effect the dielectric constant of the soils, thus leading to a difference in phase between adjacent clearcut and standing forests. We would expect this relationship to be random in space and time. The temporal and spatial relationship between the phase differences of adjacent clearcut and standing forests will indicate which of the aforementioned explanations have caused the observed signal. Specifically, the baseline dependency of the adjacent phase differences must be determined. Comparisons of these clearcut signals with records of logging in the area will allow for identification of any trends in phase differences that correlate with distinct stages of clearcutting. Ultimately we hope to provide an explanation for a prominent non-tectonic signal found in interferograms of the Pacific Northwest, which may improve our interpretation of tectonic signals and may also have applications to monitoring tree growth in clearcut regions.

  20. The Perfect Fire? Aging Stands in the Alaskan Boreal Forest Encounter Global Warming

    NASA Astrophysics Data System (ADS)

    Mann, D.; Rupp, S.; Duffy, P.

    2008-12-01

    The ecological responses of the boreal forest to climate change have global significance because of the large amount of carbon stored in its soils and biomass. Fire, mostly ignited by lightning, is the keystone disturbance agent in this forest. It triggers cycles of forest succession in its wake, and burning is the main avenue for carbon release back to the atmosphere. We studied the interactions between climate, fires, forest succession, and the age distributions of forest stands in a 60-million hectare region of Interior Alaska over the past 150 years. First we developed a statistical model relating climate to area burned over the period of record (1950-2005). Next we combined this model with climate reconstructions to extend the estimates of area burned back to A.D. 1860. We checked the resultant fire history against stand-age data from 5000 living trees sampled in the study region. Then we fed the history of area burned into a computer model that simulates forest succession on real landscapes. Results show striking changes in the means and variances of stand ages over the last 150 years in response to interactions between climate change and the successional dynamics of the boreal forest. Average stand age increased steadily between 1880 and 1940 and has fluctuated at high levels since then, indicating a historically unusual abundance of flammable stands. This accumulation of old stands has created the potential for unusually large fires. Some support for this conclusion comes from the unprecedented large sizes of the areas burned in 2004 and 2005. Further support comes when we add to the analysis the forecasts made by global climate models for Alaska over the next twenty years. Bracketing estimates for climate warming and precipitation change suggest that warmer, drier summers combined with aging forest stands will cause a series of unusually large fires, the like of which have not occurred in the region for >150 years. We infer that the enhanced burning of the

  1. A stand-replacing fire history in upper montane forests of the southern Rocky Mountains

    USGS Publications Warehouse

    Margolis, E.Q.; Swetnam, T.W.; Allen, C.D.

    2007-01-01

    Dendroecological techniques were applied to reconstruct stand-replacing fire history in upper montane forests in northern New Mexico and southern Colorado. Fourteen stand-replacing fires were dated to 8 unique fire years (1842-1901) using four lines of evidence at each of 12 sites within the upper Rio Grande Basin. The four lines of evidence were (i) quaking aspen (Populus tremuloides Michx.) inner-ring dates, (ii) fire-killed conifer bark-ring dates, (iii) tree-ring width changes or other morphological indicators of injury, and (iv) fire scars. The annual precision of dating allowed the identification of synchronous stand-replacing fire years among the sites, and co-occurrence with regional surface fire events previously reconstructed from a network of fire scar collections in lower elevation pine forests across the southwestern United States. Nearly all of the synchronous stand-replacing and surface fire years coincided with severe droughts, because climate variability created regional conditions where stand-replacing fires and surface fires burned across ecosystems. Reconstructed stand-replacing fires that predate substantial Anglo-American settlement in this region provide direct evidence that stand-replacing fires were a feature of high-elevation forests before extensive and intensive land-use practices (e.g., logging, railroad, and mining) began in the late 19th century. ?? 2007 NRC.

  2. Invistigation on Canopy Height and Density Differentiations in the Managed and Unmanaged Forest Stands Using LIDAR Data (case Study: Shastkalateh Forest, Gorgan)

    NASA Astrophysics Data System (ADS)

    Shataee, Sh.; Mohammadi, J.

    2015-12-01

    Forest management plans are interesting to keep the forest stand natural composite and structure after silvicultural and management treatments. In order to investigate on stand differences made by management treatments, comparing of these stands with unmanaged stands as natural forests is necessary. Aerial laser scanners are providing suitable 3D information to map the horizontal and vertical characteristics of forest structures. In this study, different of canopy height and canopy cover variances between managed and unmanaged forest stands as well as in two dominant forest types were investigated using Lidar data in Dr. Bahramnia forest, Northern Iran. The in-situ information was gathered from 308 circular plots by a random systematic sampling designs. The low lidar cloud point data were used to generate accurate DEM and DSM models and plot-based height statistics metrics and canopy cover characteristics. The significant analyses were done by independent T-test between two stands in same dominant forest types. Results showed that there are no significant differences between canopy cover mean in two stands as well as forest types. Result of statistically analysis on height characteristics showed that there are a decreasing the forest height and its variance in the managed forest compared to unmanaged stands. In addition, there is a significant difference between maximum, range, and mean heights of two stands in 99 percent confidence level. However, there is no significant difference between standard deviation and canopy height variance of managed and unmanged stands. These results showd that accomplished management treatments and cuttings could lead to reducing of height variances and converting multi-layers stands to two or single layers. Results are also showed that the canopy cover densities in the managed forest stands are changing from high dense cover to dense cover.

  3. The long-term hydrological effect of forest stands on the stability of slopes

    NASA Astrophysics Data System (ADS)

    Bogaard, T. A.; Meng, W.; van Beek, L. P. H.

    2012-04-01

    Forest is widely known to improve slope stability as a result of mechanical and hydrological effects. While the mechanics underlying the stabilizing process of root reinforcement are well understood and quantified, the influence of forest on the occurrence of critical hydrological conditions in terms of suction or pore pressure remains uncertain. Due to seasonal and inter-annual fluctuations, the stabilizing influence of evaporation and transpiration is difficult to isolate from the overall noise of the hydrological signal. More long-term effects of forest stands on soil development are highly variable and thus difficult to observe and quantify. Often these effects are ambivalent, having potentially a stabilizing or destabilizing influence on a slope under particular conditions (e.g., more structured soils leading to both rapid infiltration and drainage). Consequently, it can be postulated that forests will hydrologically influence the magnitude-frequency distribution of landsliding, not only at the stand level but also on a regional scale through the groundwater system. The overall aim of this research is to understand and quantify the stabilizing hydrological effect of forests on potentially unstable slopes. To this end, we focus on the changes in the magnitude-frequency distribution of landsliding that arise as a result of variations in evapotranspiration losses over the life cycle of stands. Temporal variations in evapotranspiration comprise first of all the interception that can account for an important amount of evaporation from a forest, and that changes with seasonal and annual variations in the interception capacity of the canopy and forest floor. Transpiration also represents an important loss that varies over the various growth stages of a forest stand. Based on a literature review of water consumption by tree species and water balance studies of forested catchments we defined the potential transpiration for different growth stages. This information we

  4. Denitrification in sediments from the hyporheic zone adjacent to a small forested stream

    USGS Publications Warehouse

    Duff, J.H.; Triska, F.J.

    1990-01-01

    Denitrifying potentials increased with increasing distance from the stream channel. Dissolved oxygen was 100% of the concentration expected in equilibrium with the atmosphere in water obtained from monitoring wells immediately adjacent to the stream but was as low as 7% of the expected value in water 11.4 m inland. Both nitrate and dissolved organic carbon decreased over summer in wells at the base of the alder-forested slope. A 48-h injection of nitrate-amended stream water into hyporheic water 8.4 m inland stimulated nitrous oxide production in the presence of acetylene. Nitrous oxide was generated as nitrate and acetylene were co-transported to a well 13 m down-gradient. Acetylene-block experiments coupled with the chemistry data suggest that denitrification can modify the chemistry of water during passage through the hyporheic zone. -from Authors

  5. Observations of tidal flux between a submersed aquatic plant stand and the adjacent channel in the Potomac River near Washington, D.C.

    USGS Publications Warehouse

    Rybicki, N.B.; Jenter, H.L.; Carter, V.; Baltzer, R.A.; Turtora, M.

    1997-01-01

    Dye injection studies and direct velocity and water-level measurements were made in macrophyte stands and adjacent channels in order to observe the effects of the macrophyte stand on flow and mass exchange in the tidal Potomac River. During the summer, dense stands of submersed aquatic plants cover most shoals <2 m deep. Continuous summertime water-level records within a submersed aquatic plant stand and in the adjacent channel revealed time-varying gradients in water-surface elevation between the two areas. Water-level gradients are created by differing rates of tidal water-level change in vegetated and unvegetated areas. Results were consistent with the idea that on a rising tide the water was slower to enter a macrophyte stand, and on a falling tide it was slower to leave it. Differences in water elevation between the stand and the open channel generated components of velocity in the stand that were at right angles to the line of flow in the channel. Seasonal differences in flow speed and direction over the shoals indicate substantial differences in resistance to flow as a result of the vegetation.

  6. A database for the monitoring of thermal anomalies over the Amazon forest and adjacent intertropical oceans.

    PubMed

    Jiménez-Muñoz, Juan C; Mattar, Cristian; Sobrino, José A; Malhi, Yadvinder

    2015-01-01

    Advances in information technologies and accessibility to climate and satellite data in recent years have favored the development of web-based tools with user-friendly interfaces in order to facilitate the dissemination of geo/biophysical products. These products are useful for the analysis of the impact of global warming over different biomes. In particular, the study of the Amazon forest responses to drought have recently received attention by the scientific community due to the occurrence of two extreme droughts and sustained warming over the last decade. Thermal Amazoni@ is a web-based platform for the visualization and download of surface thermal anomalies products over the Amazon forest and adjacent intertropical oceans using Google Earth as a baseline graphical interface (http://ipl.uv.es/thamazon/web). This platform is currently operational at the servers of the University of Valencia (Spain), and it includes both satellite (MODIS) and climatic (ERA-Interim) datasets. Thermal Amazoni@ is composed of the viewer system and the web and ftp sites with ancillary information and access to product download. PMID:26029379

  7. A database for the monitoring of thermal anomalies over the Amazon forest and adjacent intertropical oceans

    PubMed Central

    Jiménez-Muñoz, Juan C.; Mattar, Cristian; Sobrino, José A.; Malhi, Yadvinder

    2015-01-01

    Advances in information technologies and accessibility to climate and satellite data in recent years have favored the development of web-based tools with user-friendly interfaces in order to facilitate the dissemination of geo/biophysical products. These products are useful for the analysis of the impact of global warming over different biomes. In particular, the study of the Amazon forest responses to drought have recently received attention by the scientific community due to the occurrence of two extreme droughts and sustained warming over the last decade. Thermal Amazoni@ is a web-based platform for the visualization and download of surface thermal anomalies products over the Amazon forest and adjacent intertropical oceans using Google Earth as a baseline graphical interface (http://ipl.uv.es/thamazon/web). This platform is currently operational at the servers of the University of Valencia (Spain), and it includes both satellite (MODIS) and climatic (ERA-Interim) datasets. Thermal Amazoni@ is composed of the viewer system and the web and ftp sites with ancillary information and access to product download. PMID:26029379

  8. Spatial and thematic assessment of object-based forest stand delineation using an OFA-matrix

    NASA Astrophysics Data System (ADS)

    Hernando, A.; Tiede, D.; Albrecht, F.; Lang, S.

    2012-10-01

    The delineation and classification of forest stands is a crucial aspect of forest management. Object-based image analysis (OBIA) can be used to produce detailed maps of forest stands from either orthophotos or very high resolution satellite imagery. However, measures are then required for evaluating and quantifying both the spatial and thematic accuracy of the OBIA output. In this paper we present an approach for delineating forest stands and a new Object Fate Analysis (OFA) matrix for accuracy assessment. A two-level object-based orthophoto analysis was first carried out to delineate stands on the Dehesa Boyal public land in central Spain (Avila Province). Two structural features were first created for use in class modelling, enabling good differentiation between stands: a relational tree cover cluster feature, and an arithmetic ratio shadow/tree feature. We then extended the OFA comparison approach with an OFA-matrix to enable concurrent validation of thematic and spatial accuracies. Its diagonal shows the proportion of spatial and thematic coincidence between a reference data and the corresponding classification. New parameters for Spatial Thematic Loyalty (STL), Spatial Thematic Loyalty Overall (STLOVERALL) and Maximal Interfering Object (MIO) are introduced to summarise the OFA-matrix accuracy assessment. A stands map generated by OBIA (classification data) was compared with a map of the same area produced from photo interpretation and field data (reference data). In our example the OFA-matrix results indicate good spatial and thematic accuracies (>65%) for all stand classes except for the shrub stands (31.8%), and a good STLOVERALL (69.8%). The OFA-matrix has therefore been shown to be a valid tool for OBIA accuracy assessment.

  9. Forest Stand Segmentation Using Airborne LIDAR Data and Very High Resolution Multispectral Imagery

    NASA Astrophysics Data System (ADS)

    Dechesne, Clément; Mallet, Clément; Le Bris, Arnaud; Gouet, Valérie; Hervieu, Alexandre

    2016-06-01

    Forest stands are the basic units for forest inventory and mapping. Stands are large forested areas (e.g., ≥ 2 ha) of homogeneous tree species composition. The accurate delineation of forest stands is usually performed by visual analysis of human operators on very high resolution (VHR) optical images. This work is highly time consuming and should be automated for scalability purposes. In this paper, a method based on the fusion of airborne laser scanning data (or lidar) and very high resolution multispectral imagery for automatic forest stand delineation and forest land-cover database update is proposed. The multispectral images give access to the tree species whereas 3D lidar point clouds provide geometric information on the trees. Therefore, multi-modal features are computed, both at pixel and object levels. The objects are individual trees extracted from lidar data. A supervised classification is performed at the object level on the computed features in order to coarsely discriminate the existing tree species in the area of interest. The analysis at tree level is particularly relevant since it significantly improves the tree species classification. A probability map is generated through the tree species classification and inserted with the pixel-based features map in an energetical framework. The proposed energy is then minimized using a standard graph-cut method (namely QPBO with α-expansion) in order to produce a segmentation map with a controlled level of details. Comparison with an existing forest land cover database shows that our method provides satisfactory results both in terms of stand labelling and delineation (matching ranges between 94% and 99%).

  10. Carbon dynamics of two adjacent temperate forests under similar climatic conditions

    NASA Astrophysics Data System (ADS)

    Malla Thakuri, B.; Kim, J.

    2012-12-01

    The proximity (< 1.5 km) of the two KoFlux towers (i.e., Gwangneung coniferous forest site, GCK and deciduous forest site, GDK) provides an excellent opportunity to study carbon dynamics of the two different plant functional types under similar climate and environmental conditions. We have analyzed the CO2 flux data measured by eddy covariance from 2007 to 2010 at GCK and GDK sites. Our objectives were (1) to compare and contrast the seasonality and inter-annual variability in net ecosystem CO2 exchange (NEE) of the two adjacent forests and (2) to interpret their carbon dynamics in the framework of resilience concept. The multi-year measurements of CO2 fluxes at both sites showed contrasting inter-annual trends. Overall, both the annual gross primary productivity (GPP) and ecosystem respiration (RE) were higher for GCK site with an average NEE of -220 (±137) g C m-2 yr-1 while that of GDK was -67 (±58) g C m-2 yr-1. The GCK showed a continuous, threefold increase in NEE with lower water use efficiency whereas the GDK fluctuated between carbon source and weak to moderate carbon sink. Each year, both sites manifested a mid-season depression in GPP (and thus NEE), which was more pronounced at GCK. On a seasonal basis, summer was the most productive for GDK while spring for GCK. The results are interpreted in terms of phenology and different stages of adaptive cycles. Acknowledgment This work was funded by the Korea Meteorological Administration Research and Development Program under Grant CATER 2012-3030.

  11. Use of remotely sensed data for assessing forest stand conditions in the Eastern United States

    NASA Technical Reports Server (NTRS)

    Williams, D. L.; Nelson, R. F.

    1986-01-01

    Techniques for the detection, classification, and measurement of forest disturbances, using digital Landsat data for three study areas (Pennsynvania, North Carolina, and Maine) are reported. Results with respect to (1) the delineation and assessment of forest damage due to the use of two forest insect defoliators, and (2) qualitative assessment of the Multispectral Scanner (MSS) and the Thematic Mapper data for delineating forest stand characteristics are presented. Key results include a development of a statewide MSS digital data base and associated image-processing techniques for accurately delineating insect-damaged and healthy forest areas. For classification of broad land-cover classes which are spectrally homogeneous, the accuracy yielded by the use of either MSS data or TM Simulator data is similar. However, the TMS data provided 20 percent accuracy improvement over the MSS results when detailed (Level III) forest classes were mapped.

  12. Soil mesofauna in disturbed spruce forest stands near Čertovo and Plešné Lakes, the Bohemian Forest: preliminary results

    NASA Astrophysics Data System (ADS)

    Čuchta, Peter; Starý, Jozef

    2016-04-01

    The soil microarthropod communities were studied in disturbed spruce forest stands in the catchments areas of Čertovo (CT) and Plešné (PL) Lakes in the Bohemian Forest, Czech Republic. The study is focused on the impact of the windthrow, bark beetle outbreak damage and consecutive changes in the forest stands including soil environment. Within the soil microarthropods, two main groups, Collembola (Hexapoda) and Oribatida (Acari) are analysed. Four different treatments were selected for the study on both study areas: CT1 and PL1 stands - undamaged control forest stands, CT2 and PL2 stands - "dead" forest stands damaged by bark beetle, CT3 and PL3 stands - slightly managed windthrown forest stands left for the natural succession, and CT4 and PL4 stands - harvested windthrown stands. Soil samples were taken in June (CT1/PL1 - CT3/PL3), July and October (CT1/PL1 - CT4/PL4) 2012 from each treatment. Microarthropods were subsequently extracted in a modified high-gradient apparatus in the laboratory for seven days. Finally, the comparison of the microarthropod assemblages found at different treatment stands was performed. The most abundant groups in both study areas (Čertovo and Plešné Lakes) were Collembola and Oribatida with considerable diferences within particular treatments and in time as well.

  13. Predicting forested catchment evapotranspiration and streamflow from stand sapwood area and Aridity Index

    NASA Astrophysics Data System (ADS)

    Lane, Patrick

    2016-04-01

    Estimating the water balance of ungauged catchments has been the subject of decades of research. An extension of the fundamental problem of estimating the hydrology is then understanding how do changes in catchment attributes affect the water balance component? This is a particular issue in forest hydrology where vegetation exerts such a strong influence on evapotranspiration (ET), and consequent streamflow (Q). Given the primacy of trees in the water balance, and the potential for change to species and density through logging, fire, pests and diseases and drought, methods that directly relate ET/Q to vegetation structure, species, and stand density are very powerful. Plot studies on tree water use routinely use sapwood area (SA) to calculate transpiration and upscale to the stand/catchment scale. Recent work in south eastern Australian forests have found stand-wide SA to be linearly correlated (R2 = 0.89) with long term mean annual loss (P-Q), and hence, long term mean annual catchment streamflow. Robust relationships can be built between basal area (BA), tree density and stand SA. BA and density are common forest inventory measurements. Until now, no research has related the fundamental stand attribute of SA to streamflow. The data sets include catchments that have been thinned and with varying age classes. Thus far these analyses have been for energy limited systems in wetter forest types. SA has proven to be a more robust biometric than leaf area index which varies seasonally. That long term ET/Q is correlated with vegetation conforms to the Budyko framework. Use of a downscaled (20 m) Aridity Index (AI) has shown distinct correlations with stand SA, and therefore T. Structural patterns at a the hillslope scale not only correlate with SA and T, but also with interception (I) and forest floor evaporation (Es). These correlations between AI and I and Es have given R2 > 0.8. The result of these studies suggest an ability to estimate mean annual ET fluxes at sub

  14. Modelling Variable Fire Severity in Boreal Forests: Effects of Fire Intensity and Stand Structure

    PubMed Central

    Miquelajauregui, Yosune; Cumming, Steven G.; Gauthier, Sylvie

    2016-01-01

    It is becoming clear that fires in boreal forests are not uniformly stand-replacing. On the contrary, marked variation in fire severity, measured as tree mortality, has been found both within and among individual fires. It is important to understand the conditions under which this variation can arise. We integrated forest sample plot data, tree allometries and historical forest fire records within a diameter class-structured model of 1.0 ha patches of mono-specific black spruce and jack pine stands in northern Québec, Canada. The model accounts for crown fire initiation and vertical spread into the canopy. It uses empirical relations between fire intensity, scorch height, the percent of crown scorched and tree mortality to simulate fire severity, specifically the percent reduction in patch basal area due to fire-caused mortality. A random forest and a regression tree analysis of a large random sample of simulated fires were used to test for an effect of fireline intensity, stand structure, species composition and pyrogeographic regions on resultant severity. Severity increased with intensity and was lower for jack pine stands. The proportion of simulated fires that burned at high severity (e.g. >75% reduction in patch basal area) was 0.80 for black spruce and 0.11 for jack pine. We identified thresholds in intensity below which there was a marked sensitivity of simulated fire severity to stand structure, and to interactions between intensity and structure. We found no evidence for a residual effect of pyrogeographic region on simulated severity, after the effects of stand structure and species composition were accounted for. The model presented here was able to produce variation in fire severity under a range of fire intensity conditions. This suggests that variation in stand structure is one of the factors causing the observed variation in boreal fire severity. PMID:26919456

  15. Estimating Mixed Broadleaves Forest Stand Volume Using Dsm Extracted from Digital Aerial Images

    NASA Astrophysics Data System (ADS)

    Sohrabi, H.

    2012-07-01

    In mixed old growth broadleaves of Hyrcanian forests, it is difficult to estimate stand volume at plot level by remotely sensed data while LiDar data is absent. In this paper, a new approach has been proposed and tested for estimating stand forest volume. The approach is based on this idea that forest volume can be estimated by variation of trees height at plots. In the other word, the more the height variation in plot, the more the stand volume would be expected. For testing this idea, 120 circular 0.1 ha sample plots with systematic random design has been collected in Tonekaon forest located in Hyrcanian zone. Digital surface model (DSM) measure the height values of the first surface on the ground including terrain features, trees, building etc, which provides a topographic model of the earth's surface. The DSMs have been extracted automatically from aerial UltraCamD images so that ground pixel size for extracted DSM varied from 1 to 10 m size by 1m span. DSMs were checked manually for probable errors. Corresponded to ground samples, standard deviation and range of DSM pixels have been calculated. For modeling, non-linear regression method was used. The results showed that standard deviation of plot pixels with 5 m resolution was the most appropriate data for modeling. Relative bias and RMSE of estimation was 5.8 and 49.8 percent, respectively. Comparing to other approaches for estimating stand volume based on passive remote sensing data in mixed broadleaves forests, these results are more encouraging. One big problem in this method occurs when trees canopy cover is totally closed. In this situation, the standard deviation of height is low while stand volume is high. In future studies, applying forest stratification could be studied.

  16. Vegetation of the selected forest stands and land use in the Carpathian Mountains.

    PubMed

    Grodzińska, Krystyna; Godzik, Barbara; Fraczek, Witold; Badea, Ovidiu; Oszlányi, Július; Postelnicu, Daniela; Shparyk, Yuriy

    2004-07-01

    Within the framework of the project "Effects of forest health on biodiversity with emphasis on air pollution in the Carpathian Mountains" 26 permanent study sites were established in the vicinity of the ozone monitoring sites. The study sites were located on the NW-SE transect through the Western (12 sites), Eastern (11 sites) and Southern (3 sites) Carpathians in forest ecosystems typical of each area. Some of the forest monitoring sites were located in national parks, biosphere reserves and areas of protected landscape. Each permanent site of 0.7 ha area consisted of 5 small 500m(2) circular plots, arranged in the form of a cross, i.e. four placed on the cardinal points (N, E, S, W) and one in the center. Phytosociological records were done twice during the 1998 growing season using the Braun-Blanquet's method. The study sites represented various types of forest: Picea abies stands (8), beech (Fagus sylvatica) stands (10), fir (Abies alba) stands (2) and mixed beech-fir, spruce-fir and beech-spruce stands (6). Age of most stands was 80-100 years. Degree of crown damage varied greatly between sites, a percentage of damaged trees decrease in Carpathians from West to East. It corresponds well with the O(3) level in these areas. Typical damage by O(3) in herb layer species in several Carpathian sites were found. Land-use map for the entire Carpathian Mountains and two detailed land use maps for Tatras (Western Carpathians) and Retezat (Southern Carpathians) are presented. A little more than half of the Carpathian territory is forested. The most densely forested are Eastern Carpathians, while the most sparsely Western Carpathians. Arable lands occupy 22.6% of the Carpathians, pastures and meadows 6.2%, water bodies 1.9%, and build up areas several percent. In the highest elevation of the Carpathians alpine meadows (11.3%) and rocks (3.5%) are distributed. PMID:15046837

  17. Approximations of stand water use versus evapotranspiration from three mangrove forests in southwest Florida, USA

    USGS Publications Warehouse

    Krauss, Ken W.; Barr, Jordan G.; Engel, Victor C.; Fuentes, Jose D.; Wang, Hongqing

    2014-01-01

    Leaves from mangrove forests are often considered efficient in the use of water during photosynthesis, but less is known about whole-tree and stand-level water use strategies. Are mangrove forests as conservative in water use as experimental studies on seedlings imply? Here, we apply a simple model to estimate stand water use (S), determine the contribution of S to evapotranspiration (ET), and approximate the distribution of S versus ET over annual cycles for three mangrove forests in southwest Florida, USA. The value of S ranged from 350 to 511 mm year−1 for two mangrove forests in Rookery Bay to 872 mm year−1 for a mangrove forest along the Shark River in Everglades National Park. This represents 34–49% of ET for Rookery Bay mangroves, a rather conservative rate ofS, and 63–66% of ET for the Shark River mangroves, a less conservative rate of S. However, variability in estimates of S in mangroves is high enough to require additional study on the spatial changes related to forest structural shifts, different tidal regimes, and variable site-specific salinity concentrations in multiple mangrove forests before a true account of water use conservation strategies can be understood at the landscape scale. Evidence does suggest that large, well-developed mangrove forests have the potential to contribute considerably to the ET balance; however, regionally most mangrove forests are much smaller in stature in Florida and likely contribute less to regional water losses through stand-level transpiration.

  18. LEAF AREA INDEX (LAI) CHANGE DETECTION ON LOBLOLLY PINE FOREST STANDS WITH COMPLETE UNDERSTORY REMOVAL

    EPA Science Inventory

    The confounding effect of understory vegetation contributions to satellite derived
    estimates of leaf area index (LAI) was investigated on two loblolly pine (Pinus taeda) forest stands located in the southeastern United States. Previous studies have shown that understory can a...

  19. LEAF AREA INDEX (LAI) CHANGE DETECTION ON LOBLOLLY PINE FOREST STANDS WITH COMPLETE UNDERSTORY REMOVAL

    EPA Science Inventory

    The confounding effect of understory vegetation contributions to satellite derived estimates of leaf area index (LAI) was investigated on two loblolly pine forest stands located in the southeastern United States. Previous studies have shown that understory can account from 0-40%...

  20. Seasonal trends in environmental tritium concentrations in a small forest adjacent to a radioactive waste storage area

    SciTech Connect

    Amano, Hikaru ); Garten, C.T. Jr. )

    1991-01-01

    Tritium (HTO) concentrations were studied for an entire year in a floodplain forest adjacent to a low-level radioactive solid waste storage area (SWSA No. 5) at Oak Ridge National Laboratory (ORNL) near Oak Ridge, Tennessee, USA. Tritium in soil was the principal source of HTO to the deciduous forest. Evaporation from the surface soil along with transpiration from trees leaves both contributed to HTO in the forest atmosphere. During the growing season, transpiration was the principal contributor of HTO to the forest atmosphere, while during the dormant season, the main source of atmospheric HTO was evaporation from the surface soil. Seasonal changes and the characteristics of vegetation will influence the relative importance of evaporation and transpiration as sources of atmospheric HTO near the ground in temperate deciduous forests. 8 refs., 9 figs.

  1. Seasonal trends in environmental tritium concentrations in a small forest adjacent to a radioactive waste storage area

    SciTech Connect

    Amano, H. ); Garten, C.T. Jr. . Environmental Sciences Div.)

    1992-03-01

    Tritium (HTO) concentrations were studied for an entire year in a floodplain forest adjacent to a low-level radioactive solid waste storage areas (SWSA No. 5) at Oak Ridge National Laboratory (ORNL) near Oak Ridge, Tennessee, USA. Tritium in soil was the principal source of HTO to the deciduous forest. Evaporation from the surface soil along with transpiration from tree leaves both contributed to HTO in the forest atmosphere. During the growing season, transpiration was the principal contributor of HTO to the forest atmosphere, while during he dormant season, the main source of atmospheric HTO was evaporation from the surface soil. This paper discovers seasonal changes and the characteristics of vegetation which will influence the relative importance of evaporation and transpiration as sources of atmospheric HTO near the ground in temperate deciduous forests.

  2. Using a Standing-Tree Acoustic Tool to Identify Forest Stands for the Production of Mechanically-Graded Lumber

    PubMed Central

    Paradis, Normand; Auty, David; Carter, Peter; Achim, Alexis

    2013-01-01

    This study investigates how the use of a Hitman ST300 acoustic sensor can help identify the best forest stands to be used as supply sources for the production of Machine Stress-Rated (MSR) lumber. Using two piezoelectric sensors, the ST300 measures the velocity of a mechanical wave induced in a standing tree. Measurements were made on 333 black spruce (Picea mariana (Mill.) BSP) trees from the North Shore region, Quebec (Canada) selected across a range of locations and along a chronosequence of elapsed time since the last fire (TSF). Logs were cut from a subsample of 39 trees, and sawn into 77 pieces of 38 mm × 89 mm cross-section before undergoing mechanical testing according to ASTM standard D-4761. A linear regression model was developed to predict the static modulus of elasticity of lumber using tree acoustic velocity and stem diameter at 1.3 m above ground level (R2 = 0.41). Results suggest that, at a regional level, 92% of the black spruce trees meet the requirements of MSR grade 1650Fb-1.5E, whilst 64% and 34% meet the 2100Fb-1.8E and 2400Fb-2.0E, respectively. Mature stands with a TSF < 150 years had 11 and 18% more boards in the latter two categories, respectively, and therefore represented the best supply source for MSR lumber. PMID:23482089

  3. Using a standing-tree acoustic tool to identify forest stands for the production of mechanically-graded lumber.

    PubMed

    Paradis, Normand; Auty, David; Carter, Peter; Achim, Alexis

    2013-01-01

    This study investigates how the use of a Hitman ST300 acoustic sensor can help identify the best forest stands to be used as supply sources for the production of Machine Stress-Rated (MSR) lumber. Using two piezoelectric sensors, the ST300 measures the velocity of a mechanical wave induced in a standing tree. Measurements were made on 333 black spruce (Picea mariana (Mill.) BSP) trees from the North Shore region, Quebec (Canada) selected across a range of locations and along a chronosequence of elapsed time since the last fire (TSF). Logs were cut from a subsample of 39 trees, and sawn into 77 pieces of 38 mm × 89 mm cross-section before undergoing mechanical testing according to ASTM standard D-4761. A linear regression model was developed to predict the static modulus of elasticity of lumber using tree acoustic velocity and stem diameter at 1.3 m above ground level (R2 = 0.41). Results suggest that, at a regional level, 92% of the black spruce trees meet the requirements of MSR grade 1650Fb-1.5E, whilst 64% and 34% meet the 2100Fb-1.8E and 2400Fb-2.0E, respectively. Mature stands with a TSF < 150 years had 11 and 18% more boards in the latter two categories, respectively, and therefore represented the best supply source for MSR lumber. PMID:23482089

  4. Effect of stand age on whole ecosystem CO2 exchange in the Canadian boreal forest

    NASA Astrophysics Data System (ADS)

    Litvak, Marcy; Miller, Scott; Wofsy, Steve C.; Goulden, Michael

    2003-02-01

    One of the key steps to estimating the current and future contribution of boreal forests to the global carbon cycle is quantifying the role recovery from fire plays in stand level carbon dynamics. We used tower-based eddy covariance to measure the CO2 exchange above five black spruce stands in central Manitoba during the 1999 and 2000 growing seasons (June-September). Fluxes in the four youngest stands (11, 19, 36, and 70 year old burns) were measured using portable eddy flux systems stationed in each burn for 4 to 6 weeks. Fluxes in the oldest stand (˜1870 burn) were measured continuously throughout 1999 and 2000, providing a baseline for interpretation of the fluxes measured simultaneously in the younger stands. Light-saturated CO2 uptake was lowest in the 11 year old stand (-4.1 μmol m-2 s-1), high in the 19 year old stand (-8.9 μmol m-2 s-1), highest in the 36 year old stand (-10.1 μmol m-2 s-1), and moderate in the 70 and 130 year old stands (-6.3 and -7.1 μmol m-2 s-1, respectively). Whole-ecosystem respiration was lowest in the youngest burn and consistently increased with stand age. Integrated daily carbon balance changed from a slight sink at the 11 year old stand (-0.20 g C m-2 d-1) to a modest sink at the 19 year old stand (-1.9 g C m-2 d-1) to a large sink at the 36 year old stand (-3.1 g C m-2 d-1) to a modest sink at the 70 year old stand (-0.53 g C m-2 d-1) to around zero at the 130 year old stand. The results from any single tower in a boreal region are therefore unlikely to be representative of the entire region. Reliable assessments of regional carbon balance will require an approach that incorporates information on the fractional coverage of stands in different age classes and measurements of ecosystem gas exchange by representative stands within each age class.

  5. A composite L-band HH radar backscattering model for coniferous forest stands

    NASA Technical Reports Server (NTRS)

    Sun, Guoquing; Simonett, David S.

    1988-01-01

    The radar backscattering model developed by Richards et al. (1987), has been improved and further tested in this research. The trunk term may now be calculated from the exact solution to the electromagnetic wave equations instead of the corner reflector equation. Rough surface models have been introduced into the radar model, so that the forward reflectance and the backscattering from the ground surface are now calculated from the same model and, thus, are consistent. The number of trees in an individual pixel is assumed to be Poisson distributed, with tree height in a stand log-normally distributed. The simulated results show that the match of backscattering coefficients for eight forest stands between SIR-B image data and the simulated results are satisfying, and that the trunk term now seems to be convincingly established as the dominant term in the L-band HH radar return from coniferous forest stands.

  6. [Litterfalls of major forest stands at Baiyunshan scenic spot of Guangzhou].

    PubMed

    Zeng, Shucai; Su, Zhiyao; Gu, Yankun; Xie, Zhengsheng; Liu, Yuexiu

    2003-01-01

    The productions, seasonal dynamics, macronutrient contents and decomposition rates of the litterfalls of four typical stands, e.g., Pinus massoniana plantation, secondary evergreen broadleaved forest, Acacia mangium plantation and Schima superba-Acacia mangium plantation at the scenic Baiyunshan of Guangzhou were studied. The litterfall productions of four stands in 1998 were 8.34, 6.77, 6.31 and 11.54 t.hm-2, respectively. The seasonal dynamics of litterfall amounts demonstrated the single-peak model with the peak period in June and July. The total amounts of macronutrients returned to the forest land by means of litters in the four stands in 1998 were 26.30, 69.81, 54.9 and 152.24 kg.hm-2, respectively. The annual decomposition rates of the litterfalls were 24.4%, 53.4%, 52.4% and 57.4%. PMID:12722462

  7. Remotely sensed biomass over steep slopes: An evaluation among successional stands of the Atlantic Forest, Brazil

    NASA Astrophysics Data System (ADS)

    Barbosa, Jomar Magalhães; Melendez-Pastor, Ignacio; Navarro-Pedreño, Jose; Bitencourt, Marisa Dantas

    2014-02-01

    Remotely sensed images have been widely used to model biomass and carbon content on large spatial scales. Nevertheless, modeling biomass using remotely sensed data from steep slopes is still poorly understood. We investigated how topographical features affect biomass estimation using remotely sensed data and how such estimates can be used in the characterization of successional stands in the Atlantic Rainforest in southeastern Brazil. We estimated forest biomass using a modeling approach that included the use of both satellite data (LANDSAT) and topographic features derived from a digital elevation model (TOPODATA). Biomass estimations exhibited low error predictions (Adj. R2 = 0.67 and RMSE = 35 Mg/ha) when combining satellite data with a secondary geomorphometric variable, the illumination factor, which is based on hill shading patterns. This improved biomass prediction helped us to determine carbon stock in different forest successional stands. Our results provide an important source of modeling information about large-scale biomass in remaining forests over steep slopes.

  8. Functional groups show distinct differences in nitrogen cycling during early stand development: implications for forest management.

    SciTech Connect

    Aubrey, Doug, P.; Coyle, David, R. Coleman, Mark, D.

    2011-08-26

    Nutrient acquisition of forest stands is controlled by soil resource availability and belowground production, but tree species are rarely compared in this regard. Here, we examine ecological and management implications of nitrogen (N) dynamics during early forest stand development in productive commercial tree species with narrow (Populus deltoides Bartr. and Platanus occidentalis L.) and broad (Liquidambar styraciflua L. and Pinus taeda L.) site requirements while grown with a range of nutrient and water resources. We constructed N budgets by measuring N concentration ([N]) and N content (N{sub C}) of above- and belowground perennial and ephemeral tissues, determined N uptake (N{sub UP}), and calculated N use efficiency (NUE). Forest stands regulated [N] within species-specific operating ranges without clear temporal or treatment patterns, thus demonstrating equilibrium between tissue [N] and biomass accumulation. Forest stand N{sub C} and N{sub UP} increased with stand development and paralleled treatment patterns of biomass accumulation, suggesting productivity is tightly linked to N{sub UP}. Inclusion of above- and belowground ephemeral tissue turnover in N{sub UP} calculations demonstrated that maximum N demand for narrow-sites adapted species exceeded 200 kg N ha{sup -1} year{sup -1} while demand for broad-site adapted species was below this level. NUE was species dependent but not consistently influenced by N availability, suggesting relationships between NUE and resource availability were species dependent. Based on early stand development, species with broad site adaptability are favored for woody cropping systems because they maintain high above- and belowground productivity with minimal fertilization requirements due to higher NUE than narrow site adapted species.

  9. Litter production, soil organic matter dynamics and microbial activity in two coeval forest stands on Mount Vesuvius

    NASA Astrophysics Data System (ADS)

    de Marco, Anna; Esposito, Fabrizio; Giordano, Maria; Vittozzi, Paola; Virzo de Santo, Amalia

    2010-05-01

    Forest ecosystems in different climatic zones may accumulate different amounts of soil organic matter (SOM) with different chemical-physical properties. C inputs to SOM are related to net primary production, however C accumulation in the soil largely depends on the balance between net primary production and decomposition. On the other side rates of SOM decomposition are the major control over the supply of mineral nutrients to vegetation and thus over primary production. This study was performed in two coeval (36 years old), adjacent forest stands, a Corsican pine (Pinus nigra Arn.) and a Black locust (Robinia pseudoacacia L.) forest (Atrio del Cavallo, 40° 49'N, 14° 26'E; 810 a.s.l.). The two forests were implanted in 1970 on piroclastic material of the last eruption of Mount Vesuvius (1944). We assessed the quantity and the quality of SOM in a vertical gradient in the continuum of the litter layer, humus layer and mineral soil for the whole soil profile. Moreover we estimated litter production and decomposition, litter and mineral soil (0-5cm) respiration as well as microbial biomass and total and active fungal biomass. Litter fall (measured throughout the years 2006-2008) was higher in the Corsican pine than in the Black locust stand (5234 vs. 2396 g/m2/y). Black locust leaf litter and Corsican pine needle litter reached respectively 60 % and 50% of initial mass after 600 days in situ decomposition. Consistently with the lower litter input and the higher decomposition of black locust, the amount of organic C in the organic soil layers (litter + humus), was significantly higher in the Corsican pine as compared to the Black locust stand (2702 vs. 1636 g/m2). In contrast, in the mineral layers (0-15 cm) the amount of soil organic C was slightly higher in Black locust than in Corsican pine stand (136 vs. 116 g/m2). Litter quality, decomposition dynamics, and SOM quality and activity may help to understand the reason for the uneven distribution of organic carbon

  10. Relating Demographic Characteristics of a Small Mammal to Remotely Sensed Forest-Stand Condition

    PubMed Central

    Lada, Hania; Thomson, James R.; Cunningham, Shaun C.; Mac Nally, Ralph

    2014-01-01

    Many ecological systems around the world are changing rapidly in response to direct (land-use change) and indirect (climate change) human actions. We need tools to assess dynamically, and over appropriate management scales, condition of ecosystems and their responses to potential mitigation of pressures. Using a validated model, we determined whether stand condition of floodplain forests is related to densities of a small mammal (a carnivorous marsupial, Antechinus flavipes) in 60 000 ha of extant river red gum (Eucalyptus camaldulensis) forests in south-eastern Australia in 2004, 2005 and 2011. Stand condition was assessed remotely using models built from ground assessments of stand condition and satellite-derived reflectance. Other covariates, such as volumes of fallen timber, distances to floods, rainfall and life stages were included in the model. Trapping of animals was conducted at 272 plots (0.25 ha) across the region. Densities of second-year females (i.e. females that had survived to a second breeding year) and of second-year females with suckled teats (i.e. inferred to have been successful mothers) were higher in stands with the highest condition. There was no evidence of a relationship with stand condition for males or all females. These outcomes show that remotely-sensed estimates of stand condition (here floodplain forests) are relatable to some demographic characteristics of a small mammal species, and may provide useful information about the capacity of ecosystems to support animal populations. Over-regulation of large, lowland rivers has led to declines in many facets of floodplain function. If management of water resources continues as it has in recent decades, then our results suggest that there will be further deterioration in stand condition and a decreased capacity for female yellow-footed antechinuses to breed multiple times. PMID:24621967

  11. Relating demographic characteristics of a small mammal to remotely sensed forest-stand condition.

    PubMed

    Lada, Hania; Thomson, James R; Cunningham, Shaun C; Mac Nally, Ralph

    2014-01-01

    Many ecological systems around the world are changing rapidly in response to direct (land-use change) and indirect (climate change) human actions. We need tools to assess dynamically, and over appropriate management scales, condition of ecosystems and their responses to potential mitigation of pressures. Using a validated model, we determined whether stand condition of floodplain forests is related to densities of a small mammal (a carnivorous marsupial, Antechinus flavipes) in 60,000 ha of extant river red gum (Eucalyptus camaldulensis) forests in south-eastern Australia in 2004, 2005 and 2011. Stand condition was assessed remotely using models built from ground assessments of stand condition and satellite-derived reflectance. Other covariates, such as volumes of fallen timber, distances to floods, rainfall and life stages were included in the model. Trapping of animals was conducted at 272 plots (0.25 ha) across the region. Densities of second-year females (i.e. females that had survived to a second breeding year) and of second-year females with suckled teats (i.e. inferred to have been successful mothers) were higher in stands with the highest condition. There was no evidence of a relationship with stand condition for males or all females. These outcomes show that remotely-sensed estimates of stand condition (here floodplain forests) are relatable to some demographic characteristics of a small mammal species, and may provide useful information about the capacity of ecosystems to support animal populations. Over-regulation of large, lowland rivers has led to declines in many facets of floodplain function. If management of water resources continues as it has in recent decades, then our results suggest that there will be further deterioration in stand condition and a decreased capacity for female yellow-footed antechinuses to breed multiple times. PMID:24621967

  12. Scots pine chemotypic characterization in a boreal forest stand

    NASA Astrophysics Data System (ADS)

    Bäck, J. K.; Aalto, J.; Henriksson, M.; Hakola, H.; Rinne, J.

    2009-12-01

    Branch scale VOC emissions and above-canopy VOC concentrations have been characterized in several long-term studies in a mature boreal Scots pine (Pinus sylvestris L.) stand in southern Finland, SMEAR II measuring station. The above-canopy monoterpene concentrations in the site have been dominated by α-pinene, which on an average is three times more abundant than the second most common monoterpene, D3-carene. On the contrary, in the branch scale measurements D3-carene is 4-5 times more abundant than α-pinene. The emitted monoterpene mixture has significant implications on air chemistry at the boundary layer, and thus a more detailed understanding on how the emissions vary within the stand is needed. To clarify the variation in the monoterpene emission mixture within the SMEAR II Scots pine population, we collected branches from 40 trees with a systematic sampling scheme, and brought them into the laboratory where we measured their emission spectrum with a gas chromatograph-mass spectrometer (GC-MS). Branches were collected from southward facing direction of the mid-canopy, and stored in cold before collecting the emissions from the topmost part of the branch into Tenax TA adsorbent. Large differences in emission spectrum were seen between the studied pine trees. α-pinene and D3-carene formed together 63-96% of the branch monoterpene emissions. Only in one tree β-pinene emissions overruled these two major components. A significant proportion (22.5%) of the pine population could be characterized as high carene emitters, i.e. their D3-carene emissions were more than 50% larger than their α-pinene emissions. In minimum the α-pinene emissions were only one tenth of the D3-carene emissions. Terpinolene emission was positively correlated with the high D3-carene emissions. Five trees (12.5%) emitted mostly α- and β-pinenes, and in these branches only remnants of D3-carene (less than 10% of total monoterpene emissions) were measured. Camphene, limonene and

  13. Forest adjacent households' voices on their perceptions and adaptation strategies to climate change in Kilombero District, Tanzania.

    PubMed

    Balama, Chelestino; Augustino, Suzana; Eriksen, Siri; Makonda, Fortunatus B S

    2016-01-01

    Climate change is a global and local challenge to both sustainable livelihoods and economic development. Tanzania as other countries of the world has been affected. Several studies have been conducted on farmers' perceptions and adaptation to climate change in the country, but little attention has been devoted to forest adjacent households in humid areas. This study assessed this gap through assessing forest adjacent households' voices on perceptions and adaptation strategies to climate change in Kilombero District, Tanzania. Data collection involved key informant interviews, focus group discussions and household questionnaires. Results showed that the majority of households perceived changed climate in terms of temperature increase, unpredictable rainfall, frequent occurrence of floods, increased dry spells during rainy season coupled with decreased water sources and emergence of new pests and diseases. The perceived change in climate has impacted agriculture productivity as the main livelihood source. Different coping and adaptation strategies are employed. These are; crop diversification, changing cropping calendar, adopting modern farming technologies, and increasing reliance on non-timber forest products. These strategies were positively and significantly influenced by socio-economic factors including household size, residence period, land ownership and household income. The study concludes that, there are changes in climatic conditions; and to respond to these climatic changes, forest adjacent households have developed numerous coping and adaptation strategies, which were positively and significantly influenced by some socio-economic factors. The study calls for actual implementation of local climate change policies and strategies in order to enhance adaptive capacity at household level. PMID:27390633

  14. Consequences of stand age and species’ functional trait changes on ecosystem water use of forests

    SciTech Connect

    Ewers, Brent; Bond-Lamberty, Benjamin; Mackay, D. Scott

    2011-07-22

    We tested whether using stomatal conductance could capture the dynamic in transpiration with forest age. To do this we by answered the question “If we chose a reference stomatal conductance from one stand age of the entire chronosequence to put into a model, would modeled transpiration be biased from the other ages?” with a resounding yes. We found that obtaining the right stomatal conductance was crucial for accurate models in two different chronosequences. This strongly suggests that stomatal conductance is the appropriate integrator of inter- and intra-species change in tree transpiration with forest age. If we had tried to use a single reference canopy stomatal conductance, it would not have been able to capture the variability in transpiration with stand age despite the suggestion that hydraulic limitation was consistently acting on the trees; the situation is even more complex in many boreal systems, where a transition to nonstomatal bryophytes may occur over the course of succession. Because we used a biophysical approach, even if our and other researchers’ chronosequences do not fit the assumptions, the results are still useful. Further, our synthesis of sap flux based estimates of tree transpiration showing a large dynamic suggest that our approach to modeling is crucial in the face of anthropogenic changes to forest age structure. We have now provided the framework for a mechanistically rigorous yet simple approach based on simple tree hydraulics to measuring and modeling stand transpiration with changing forest age and/or species composition.

  15. 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

  16. Forest structure, stand composition, and climate-growth response in montane forests of Jiuzhaigou National Nature Reserve, China.

    PubMed

    Schwartz, Mark W; Dolanc, Christopher R; Gao, Hui; Strauss, Sharon Y; Schwartz, Ari C; Williams, John N; Tang, Ya

    2013-01-01

    Montane forests of western China provide an opportunity to establish baseline studies for climate change. The region is being impacted by climate change, air pollution, and significant human impacts from tourism. We analyzed forest stand structure and climate-growth relationships from Jiuzhaigou National Nature Reserve in northwestern Sichuan province, along the eastern edge of the Tibetan plateau. We conducted a survey to characterize forest stand diversity and structure in plots occurring between 2050 and 3350 m in elevation. We also evaluated seedling and sapling recruitment and tree-ring data from four conifer species to assess: 1) whether the forest appears in transition toward increased hardwood composition; 2) if conifers appear stressed by recent climate change relative to hardwoods; and 3) how growth of four dominant species responds to recent climate. Our study is complicated by clear evidence of 20(th) century timber extraction. Focusing on regions lacking evidence of logging, we found a diverse suite of conifers (Pinus, Abies, Juniperus, Picea, and Larix) strongly dominate the forest overstory. We found population size structures for most conifer tree species to be consistent with self-replacement and not providing evidence of shifting composition toward hardwoods. Climate-growth analyses indicate increased growth with cool temperatures in summer and fall. Warmer temperatures during the growing season could negatively impact conifer growth, indicating possible seasonal climate water deficit as a constraint on growth. In contrast, however, we found little relationship to seasonal precipitation. Projected warming does not yet have a discernible signal on trends in tree growth rates, but slower growth with warmer growing season climates suggests reduced potential future forest growth. PMID:23951188

  17. Forest Structure, Stand Composition, and Climate-Growth Response in Montane Forests of Jiuzhaigou National Nature Reserve, China

    PubMed Central

    Schwartz, Mark W.; Dolanc, Christopher R.; Gao, Hui; Strauss, Sharon Y.; Schwartz, Ari C.; Williams, John N.; Tang, Ya

    2013-01-01

    Montane forests of western China provide an opportunity to establish baseline studies for climate change. The region is being impacted by climate change, air pollution, and significant human impacts from tourism. We analyzed forest stand structure and climate-growth relationships from Jiuzhaigou National Nature Reserve in northwestern Sichuan province, along the eastern edge of the Tibetan plateau. We conducted a survey to characterize forest stand diversity and structure in plots occurring between 2050 and 3350 m in elevation. We also evaluated seedling and sapling recruitment and tree-ring data from four conifer species to assess: 1) whether the forest appears in transition toward increased hardwood composition; 2) if conifers appear stressed by recent climate change relative to hardwoods; and 3) how growth of four dominant species responds to recent climate. Our study is complicated by clear evidence of 20th century timber extraction. Focusing on regions lacking evidence of logging, we found a diverse suite of conifers (Pinus, Abies, Juniperus, Picea, and Larix) strongly dominate the forest overstory. We found population size structures for most conifer tree species to be consistent with self-replacement and not providing evidence of shifting composition toward hardwoods. Climate-growth analyses indicate increased growth with cool temperatures in summer and fall. Warmer temperatures during the growing season could negatively impact conifer growth, indicating possible seasonal climate water deficit as a constraint on growth. In contrast, however, we found little relationship to seasonal precipitation. Projected warming does not yet have a discernible signal on trends in tree growth rates, but slower growth with warmer growing season climates suggests reduced potential future forest growth. PMID:23951188

  18. Post-fire stand structure impacts carbon storage within Siberian larch forests

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    Increased fire severity within boreal forests of the Siberian Arctic has the potential to alter forest stand development thereby altering carbon (C) accumulation rates and storage during the post-fire successional interval. One potential change is increased stand density, which may result from fire consumption of the soil organic layer and changes to the seedbed that favor germination and establishment of larch trees during early succession. In this study, we evaluated above- and belowground C pools across 12 stands of varying tree density within a single 75-year old fire scar located near Cherskii, Sakha Republic, Russia. In each stand, we inventoried the size and density of larch trees and large shrubs (Salix and Betula spp.), and in combination with with allometric equations, estimated aboveground contribution to C pools. We quantified woody debris C pools using the line intercept method. We sampled belowground C pools in the soil organic layer + upper (0-10 cm) mineral soil and coarse roots (> 2 mm diameter) using sediment cores and 0.25 x 0.25-m trenches, respectively. We found that high density stands store ~ 20% more C (~7,500 g C m-2) than low density stands (~5,800 g C m-2). In high density stands, about 35% more C is stored aboveground within live larch trees (1650 g C m-2) compared to low density stands (940 g C m-2), and about 15% more C is stored in the soil organic layer and upper mineral soil. Coarse root C was 20% higher in high density stands (~475 g C m-2) compared to those with low density (~350 g C m-2). Less C was stored in large shrubs in high density stands, both in aboveground portions and coarse roots, but these amounts were relatively small (< 10% of total C pools). A fire-driven shift to denser larch stands could increase C storage, leading to a negative feedback to climate, but the combined effects of density on C dynamics, summer and winter albedo, and future fire regimes will interact to determine the magnitude of any vegetation

  19. Leaf litter decomposition in temperate deciduous forest stands with a decreasing fraction of beech (Fagus sylvatica)

    PubMed Central

    Jacob, Mascha; Viedenz, Karin; Polle, Andrea

    2010-01-01

    We hypothesised that the decomposition rates of leaf litter will increase along a gradient of decreasing fraction of the European beech (Fagus sylvatica) and increasing tree species diversity in the generally beech-dominated Central European temperate deciduous forests due to an increase in litter quality. We studied the decomposition of leaf litter including its lignin fraction in monospecific (pure beech) stands and in stands with up to five tree genera (Acer spp., Carpinus betulus, Fagus sylvatica, Fraxinus excelsior, Tilia spp.) using a litterbag approach. Litter and lignin decomposition was more rapid in stand-representative litter from multispecific stands than in litter from pure beech stands. Except for beech litter, the decomposition rates of species-specific tree litter did not differ significantly among the stand types, but were most rapid in Fraxinus excelsior and slowest in beech in an interspecific comparison. Pairwise comparisons of the decomposition of beech litter with litter of the other tree species (except for Acerplatanoides) revealed a “home field advantage” of up to 20% (more rapid litter decomposition in stands with a high fraction of its own species than in stands with a different tree species composition). Decomposition of stand-representative litter mixtures displayed additive characteristics, not significantly more rapid than predicted by the decomposition of litter from the individual tree species. Leaf litter decomposition rates were positively correlated with the initial N and Ca concentrations of the litter, and negatively with the initial C:N, C:P and lignin:N ratios. The results support our hypothesis that the overall decomposition rates are mainly influenced by the chemical composition of the individual litter species. Thus, the fraction of individual tree species in the species composition seems to be more important for the litter decomposition rates than tree species diversity itself. PMID:20596729

  20. Spatial patterns in forest composition and standing dead red spruce in montane forests of the Adirondacks and northern Appalachians.

    PubMed

    Craig, B W; Friedland, A J

    1991-08-01

    The decline of red spruce (Picea rubens Sarg.) in montane forests of the northeastern United States has been previously reported. The objective of this study was to assess spatial patterns, if any, in standing dead red spruce stems in the Adirondacks of New York and northern Appalachians of Vermont, New Hampshire, and Maine. A stratified random sample of 19 mountains along a west to east transect in the Adirondacks and the northern Appalachians showed that the live basal area of all species was highest in the White Mountains (34.6 m(2) ha(-1)) and lowest in the Adirondack Mountains (23.7 m(2) ha(-1)) in the Green Mountains was significantly lower than in any other region. Intact standing dead red spruce in the Adirondack and Green Mountains (30%) was significantly higher than that in the three eastern clusters (14%). The amount of intact standing dead red spruce trees increased with elevation in only the western part of the region. With the exception of the Adirondacks, there was a greater average percent dead red spruce on the west side than on the east side of each mountain. The sum of standing dead for other tree species (average 13%) showed no statistically significant patterns with region, elevation or aspect, and was significantly lower than the amount of total dead red spruce (average 42%). The standing dead red spruce patterns we observed cannot be associated with any specific causal factors at this time. PMID:24233751

  1. Douglas-fir forests in the Oregon and Washington Cascades: relation of the herpetofauna to stand age and moisture

    USGS Publications Warehouse

    Bury, R. Bruce; Corn, P.S.

    1988-01-01

    Pitfall traps effectively sampled amphibians but not reptiles in Douglas-fir (Pseudotsuga menziesii) forests. The abundance of only one amphibian species varied across an age gradient or a moisture gradient. Salamanders and frogs that breed in ponds or streams were captured in large numbers in some stands, likely due to the presence of nearby breeding habitat rather than forest conditions. Lizards occurred mostly in dry stands and clearcuts. Time-constrained searches showed different use of downed woody debris among terrestrial salamanders. The occurrence and abundance of species in naturally regenerated forests markedly differed from clearcut stands.

  2. Distribution of deciduous stands in villages located in coniferous forest landscapes in Sweden.

    PubMed

    Mikusiński, Grzegorz; Angelstam, Per; Sporrong, Ulf

    2003-12-01

    Termination of fire along with active removal of deciduous trees in favor of conifers together with anthropogenic transformation of productive forest into agricultural land, have transformed northern European coniferous forests and reduced their deciduous component. Locally, however, in the villages, deciduous trees and stands were maintained, and have more recently regenerated on abandoned agricultural land. We hypothesize that the present distribution of the deciduous component is related to the village in-field/out-field zonation in different regions, which emerges from physical conditions and recent economic development expressed as land-use change. We analyzed the spatial distribution of deciduous stands in in-field and out-field zones of villages in 6 boreal/hemiboreal Swedish regions (Norrbotten, Angermanland, Jämtland, Dalarna, Bergslagen, Småland). In each region 6 individual quadrates 5 x 5 km centered on village areas were selected. We found significant regional differences in the deciduous component (DEC) in different village zones. At the scale of villages Angermanland had the highest mean proportion of DEC (17%) and Jämtland the lowest (2%). However, the amounts of the DEC varied systematically in in-field and out-field zones. DEC was highest in the in-field in the south (Småland), but generally low further north. By contrast, the amount of DEC in the out-field was highest in the north. The relative amount of DEC in the forest edge peaked in landscapes with the strongest decline in active agriculture (Angermanland, Dalarna, Bergslagen). Because former and present local villages are vital for biodiversity linked to the deciduous component, our results indicate a need for integrated management of deciduous forest within entire landscapes. This study shows that simplified satellite data are useful for estimating the spatial distribution of deciduous trees and stands at the landscape scale. However, for detailed studies better thematic resolution is

  3. Movements of northern flying squirrels in different-aged forest stands of western Oregon

    USGS Publications Warehouse

    Martin, K.J.; Anthony, R.G.

    1999-01-01

    In western Oregon, northern flying squirrels (Glaucomys sabrinus) are the primary prey species for northern spotted owls (Strix occidentalis caurina), an old-growth associated species. To assess differences between old-growth and second-growth habitat, we livetrapped and radiotagged 39 northern flying squirrels to estimate their home range sizes and describe movements in 2 old-growth and 2 second-growth conifer forest stands in the Cascade Mountains of central Oregon. Sampling periods were summer and fall of 1991-92. Home range sizes averaged 4.9 ha and did not differ (P > 0.30) between the 2 stand types. Male northern flying squirrels had larger (P ??? 0.03) mean home ranges (5.9 ?? 0.8 ha; ?? ?? SE; n = 20) than females (3.9 ?? 0.4 ha; n = 19). Northern flying squirrel movement distances between successive, noncorrelated telemetry locations averaged 71 m (n = 1,090). No correlation was found between distances moved and stand type or sex. Northern flying squirrel's home range sizes, movements, and densities were similar between the 2 stand types. We suggest abundance and movements of northern flying squirrels are not influencing the preferential selection of oldgrowth forests by northern spotted owls.

  4. Forest age stands affect soil respiration and litterfall in a Black pine forest managed by a shelterwood system in the Central Spain?

    NASA Astrophysics Data System (ADS)

    Hedo de Santiago, Javier; Borja, Manuel Esteban Lucas; Candel, David; Viñegla Pérez, Benjamin

    2016-04-01

    This study aims to investigate the effects that stand age and forest structure generates on soil respiration and litterfall quantity. The effect of stand age on these variables was studied in a shelterwood system Spanish Black pine chronosequence in central Iberian Peninsula composed of 0-20, 20-40, 40-60, 60-80, 80-100-year-old. For each stand age, six forest stands with similar characteristics of soil type and site preparation were used. Also, a forest area ranging 80-120 years old and without forest intervention was selected and used as control. We also measured organic matter, C:N ratio, soil moisture and pH in the top 10 mineral soil at each compartment. Soil respiration measurements were carried out in three time points (3, 8 and 12 days). Results showed a clear trend in soil respiration, comparing all the experimental areas. Soil respiration showed the same trend in all stands. It initially showed higher rates, reaching stability in the middle of the measurement process and finally lightly increasing the respiration rate. The older stands had significantly higher soil respiration than the younger stands. Soil organic matter values were also higher in the more mature stands. C:N ratio showed the opposite trend, showing lower values in the less mature stands. More mature stands clearly showed more quantity of litterfall than the younger ones and there was a positive correlation between soil respiration and litterfall. Finally, the multivariate PCA analysis clearly clustered three differenced groups: Control plot; from 100 to 40 years old and from 39 to 1 years old, taking into account both soil respiration and litterfall quantity, also separately. Our results suggest that the control plot has a better soil quality and that extreme forest stand ages (100-80 and 19-1 years old) and the associated forest structure generates differences in soil respiration.

  5. Stand-Level Gas-Exchange Responses to Seasonal Drought in Very Young Versus Old Douglas-fir Forests of the Pacific Northwest, USA

    SciTech Connect

    Wharton, S; Schroeder, M; Bible, K; Falk, M; Paw U, K T

    2009-02-23

    This study examines how stand age affects ecosystem mass and energy exchange response to seasonal drought in three adjacent Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forests. The sites include two early seral stands (ES) (0-15 years old) and an old-growth (OG) ({approx} 450-500) forest in the Wind River Experiment Forest, Washington, USA. We use eddy covariance flux measurements of carbon dioxide (F{sub NEE}), latent energy ({lambda}E) and sensible heat (H) to derive evapotranspiration rate (E{sub T}), bowen ratio ({beta}), water use efficiency (WUE), canopy conductance (G{sub c}), the Priestley-Taylor coefficient ({alpha}) and a canopy decoupling factor ({Omega}). The canopy and bulk parameters are examined to see how ecophysiological responses to water stress, including changes in available soil water ({theta}{sub r}) and vapor pressure deficit ({delta}e) differ among the two forest successional-stages. Despite very different rainfall patterns in 2006 and 2007, we observed distinct successional-stage relationships between E{sub T}, {alpha}, and G{sub c} to {delta}e and {theta}{sub r} during both years. The largest stand differences were (1) higher morning G{sub c} (> 10 mm s{sup -1}) at the OG forest coinciding with higher CO{sub 2} uptake (F{sub NEE} = -9 to -6 {micro}mol m{sup -2} s{sup -1}) but a strong negative response in G{sub c} to moderate {delta}e later in the day and a subsequent reduction in E{sub T}, and (2) higher E{sub T} at the ES stands because midday canopy conductance did not decrease until very low water availability levels (<30%) were reached at the end of the summer. Our results suggest that early seral stands are more likely than mature forests to experience declines in production if the summer drought becomes longer or intensifies because water conserving ecophysiological responses were only observed at the very end of the seasonal drought period in the youngest stands.

  6. Effect of Forest Structural Change on Carbon Storage in a Coastal Metasequoia glyptostroboides Stand

    PubMed Central

    Cheng, Xiangrong; Yu, Mukui; Wu, Tonggui

    2013-01-01

    Forest structural change affects the forest's growth and the carbon storage. Two treatments, thinning (30% thinning intensity) and underplanting plus thinning, are being implemented in a coastal Metasequoia glyptostroboides forest shelterbelt in Eastern China. The vegetation carbon storage significantly increased in the underplanted and thinned treatments compared with that in the unthinned treatment (P < 0.05). The soil and litterfall carbon storage in the underplanted treatment were significantly higher than those in the unthinned treatment (P < 0.05). The total forest ecosystem carbon storage in the underplanted and thinned treatments increased by 35.3% and 26.3%, respectively, compared with that in the unthinned treatment, an increase that mainly came from the growth of vegetation aboveground. Total ecosystem carbon storage showed no significant difference between the underplanted and thinned treatments (P > 0.05). The soil light fraction organic carbon (LFOC) was significantly higher at the 0–15 cm soil layer in the thinned and underplanted stands compared with that in the unthinned stand (P < 0.05). The soil respiration of the underplanted treatment was significantly higher than that of the unthinned treatment only in July (P < 0.05). This study concludes that 30% thinning and underplanting after thinning could be more favorable to carbon sequestration for M. glyptostroboides plantations in the coastal areas of Eastern China. PMID:24187525

  7. Accuracy of early stand exam age estimates in the Swan Valley of Western Montana. Forest Service research note

    SciTech Connect

    Hart, M.; Lesica, P.

    1994-04-01

    The stand exams conducted in western Montana over 50 years ago provide a valuable source of information on prefire suppression and preharvest condition of the region's forests. Of the early exam estimates of stand origin, 52 percent were within 20 years of estimates taken from stand exams conducted in the 1980's, and 73 percent were within 60 years. There was no significant bias toward either higher or lower age estimates. The early stand exam data can give an accurate estimate of stand age distributions over large areas.

  8. Average Stand Age from Forest Inventory Plots Does Not Describe Historical Fire Regimes in Ponderosa Pine and Mixed-Conifer Forests of Western North America

    PubMed Central

    Stevens, Jens T.; Safford, Hugh D.; North, Malcolm P.; Fried, Jeremy S.; Gray, Andrew N.; Brown, Peter M.; Dolanc, Christopher R.; Dobrowski, Solomon Z.; Falk, Donald A.; Farris, Calvin A.; Franklin, Jerry F.; Fulé, Peter Z.; Hagmann, R. Keala; Knapp, Eric E.; Miller, Jay D.; Smith, Douglas F.; Swetnam, Thomas W.; Taylor, Alan H.

    2016-01-01

    Quantifying historical fire regimes provides important information for managing contemporary forests. Historical fire frequency and severity can be estimated using several methods; each method has strengths and weaknesses and presents challenges for interpretation and verification. Recent efforts to quantify the timing of historical high-severity fire events in forests of western North America have assumed that the “stand age” variable from the US Forest Service Forest Inventory and Analysis (FIA) program reflects the timing of historical high-severity (i.e. stand-replacing) fire in ponderosa pine and mixed-conifer forests. To test this assumption, we re-analyze the dataset used in a previous analysis, and compare information from fire history records with information from co-located FIA plots. We demonstrate that 1) the FIA stand age variable does not reflect the large range of individual tree ages in the FIA plots: older trees comprised more than 10% of pre-stand age basal area in 58% of plots analyzed and more than 30% of pre-stand age basal area in 32% of plots, and 2) recruitment events are not necessarily related to high-severity fire occurrence. Because the FIA stand age variable is estimated from a sample of tree ages within the tree size class containing a plurality of canopy trees in the plot, it does not necessarily include the oldest trees, especially in uneven-aged stands. Thus, the FIA stand age variable does not indicate whether the trees in the predominant size class established in response to severe fire, or established during the absence of fire. FIA stand age was not designed to measure the time since a stand-replacing disturbance. Quantification of historical “mixed-severity” fire regimes must be explicit about the spatial scale of high-severity fire effects, which is not possible using FIA stand age data. PMID:27196621

  9. Average Stand Age from Forest Inventory Plots Does Not Describe Historical Fire Regimes in Ponderosa Pine and Mixed-Conifer Forests of Western North America.

    PubMed

    Stevens, Jens T; Safford, Hugh D; North, Malcolm P; Fried, Jeremy S; Gray, Andrew N; Brown, Peter M; Dolanc, Christopher R; Dobrowski, Solomon Z; Falk, Donald A; Farris, Calvin A; Franklin, Jerry F; Fulé, Peter Z; Hagmann, R Keala; Knapp, Eric E; Miller, Jay D; Smith, Douglas F; Swetnam, Thomas W; Taylor, Alan H

    2016-01-01

    Quantifying historical fire regimes provides important information for managing contemporary forests. Historical fire frequency and severity can be estimated using several methods; each method has strengths and weaknesses and presents challenges for interpretation and verification. Recent efforts to quantify the timing of historical high-severity fire events in forests of western North America have assumed that the "stand age" variable from the US Forest Service Forest Inventory and Analysis (FIA) program reflects the timing of historical high-severity (i.e. stand-replacing) fire in ponderosa pine and mixed-conifer forests. To test this assumption, we re-analyze the dataset used in a previous analysis, and compare information from fire history records with information from co-located FIA plots. We demonstrate that 1) the FIA stand age variable does not reflect the large range of individual tree ages in the FIA plots: older trees comprised more than 10% of pre-stand age basal area in 58% of plots analyzed and more than 30% of pre-stand age basal area in 32% of plots, and 2) recruitment events are not necessarily related to high-severity fire occurrence. Because the FIA stand age variable is estimated from a sample of tree ages within the tree size class containing a plurality of canopy trees in the plot, it does not necessarily include the oldest trees, especially in uneven-aged stands. Thus, the FIA stand age variable does not indicate whether the trees in the predominant size class established in response to severe fire, or established during the absence of fire. FIA stand age was not designed to measure the time since a stand-replacing disturbance. Quantification of historical "mixed-severity" fire regimes must be explicit about the spatial scale of high-severity fire effects, which is not possible using FIA stand age data. PMID:27196621

  10. Mapping stand-age distribution of Russian forests from satellite data

    NASA Astrophysics Data System (ADS)

    Chen, D.; Loboda, T. V.; Hall, A.; Channan, S.; Weber, C. Y.

    2013-12-01

    Russian boreal forest is a critical component of the global boreal biome as approximately two thirds of the boreal forest is located in Russia. Numerous studies have shown that wildfire and logging have led to extensive modifications of forest cover in the region since 2000. Forest disturbance and subsequent regrowth influences carbon and energy budgets and, in turn, affect climate. Several global and regional satellite-based data products have been developed from coarse (>100m) and moderate (10-100m) resolution imagery to monitor forest cover change over the past decade, record of forest cover change pre-dating year 2000 is very fragmented. Although by using stacks of Landsat images, some information regarding the past disturbances can be obtained, the quantity and locations of such stacks with sufficient number of images are extremely limited, especially in Eastern Siberia. This paper describes a modified method which is built upon previous work to hindcast the disturbance history and map stand-age distribution in the Russian boreal forest. Utilizing data from both Landsat and the Moderate Resolution Imaging Spectroradiometer (MODIS), a wall-to-wall map indicating the estimated age of forest in the Russian boreal forest is created. Our previous work has shown that disturbances can be mapped successfully up to 30 years in the past as the spectral signature of regrowing forests is statistically significantly different from that of mature forests. The presented algorithm ingests 55 multi-temporal stacks of Landsat imagery available over Russian forest before 2001 and processes through a standardized and semi-automated approach to extract training and validation data samples. Landsat data, dating back to 1984, are used to generate maps of forest disturbance using temporal shifts in Disturbance Index through the multi-temporal stack of imagery in selected locations. These maps are then used as reference data to train a decision tree classifier on 50 MODIS

  11. TCP Final Report: Measuring the Effects of Stand Age and Soil Drainage on Boreal Forest

    SciTech Connect

    Michael L. Goulden

    2007-05-02

    This was a 6-year research project in the Canadian boreal forest that focused on using field observations to understand how boreal forest carbon balance changes during recovery from catastrophic forest fire. The project began with two overarching goals: (1) to develop techniques that would all the year round operation of 7 eddy covariance sites in a harsh environment at a much lower cost than had previously been possible, and (2) to use these measurements to determine how carbon balance changes during secondary succession. The project ended in 2006, having accomplished its primary objectives. Key contributions to DOE during the study were: (1) Design, test, and demonstrate a lightweight, fully portable eddy flux system that exploits several economies of scale to allow AmeriFlux-quality measurements of CO{sub 2} exchange at many sites for a large reduction in cost (Goulden et al. 2006). (2) Added seven year-round sites to AmeriFlux, at a relatively low per site cost using the Eddy Covariance Mesonet approach (Goulden et al. 2006). These data are freely available on the AmeriFlux web site. (3) Tested and rejected the conventional wisdom that forests lose large amounts of carbon during the first decade after disturbance, then accumulate large amounts of carbon for {approx}several decades, and then return to steady state in old age. Rather, we found that boreal forests recovers quickly from fire and begins to accumulate carbon within {approx}5 years after disturbance. Additionally, we found no evidence that carbon accumulation declines in old stands (Goulden et al. 2006, Goulden et al. in prep). (4) Tested and rejected claims based on remote sensing observations (for example, Myneni et al 1996 using AVHRR) that regions of boreal forest have changed markedly in the last 20 years. Rather, we assembled a much richer data set than had been used in the past (eddy covariance observations, tree rings, biomass, NPP, AVHRR, and LandSat), which we used to establish that the

  12. Mapping forest stand complexity for woodland caribou habitat assessment using multispectral airborne imagery

    NASA Astrophysics Data System (ADS)

    Zhang, W.; Hu, B.; Woods, M.

    2014-11-01

    The decline of the woodland caribou population is a result of their habitat loss. To conserve the habitat of the woodland caribou and protect it from extinction, it is critical to accurately characterize and monitor its habitat. Conventionally, products derived from low to medium spatial resolution remote sensing data, such as land cover classification and vegetation indices are used for wildlife habitat assessment. These products fail to provide information on the structure complexities of forest canopies which reflect important characteristics of caribou's habitats. Recent studies have employed the LiDAR system (Light Detection And Ranging) to directly retrieve the three dimensional forest attributes. Although promising results have been achieved, the acquisition cost of LiDAR data is very high. In this study, utilizing the very high spatial resolution imagery in characterizing the structural development the of forest canopies was exploited. A stand based image texture analysis was performed to predict forest succession stages. The results were demonstrated to be consistent with those derived from LiDAR data.

  13. [Imitation model of 90Sr behaviour in the soil and stand of pine forest].

    PubMed

    Mamikhin, S V; Nikulina, M V

    2005-01-01

    The algorithm of display of 90Sr behaviour mechanisms in forest ecosystems by method of imitating modeling is developed. Distinctive features of algorithm: the 90Sr contents in vegetation is subdivided into two parts (outside and internal pollution), which dynamics is considered separately; dynamics of a radionuclide is considered in connection with dynamics of organic substance; it is supposed, that 90Sr behaviour in plants is similar to Ca behaviour; the biological availability 90Sr contained in a soil, is integrated function of time and physico-chemical properties of the given soil. On the basis of offered algorithm the model is constructed which is used for realization of a number of numerical experiments, including reconstruction of a situation of pollution of forest ecosystem on grey forest soils in result of Kyshtym accident. The quantitative estimations of intensity of 90Sr redistribution between stand components and soil are received. The modern problems of creation of prognostication models of 90Sr dynamics in the forest ecosystems are discussed. PMID:15906866

  14. Measuring Effective Leaf Area Index, Foliage Profile, and Stand Height in New England Forest Stands Using a Full-Waveform Ground-Based Lidar

    NASA Technical Reports Server (NTRS)

    Zhao, Feng; Yang, Xiaoyuan; Schull, Mithcell A.; Roman-Colon, Miguel O.; Yao, Tian; Wang, Zhuosen; Zhang, Qingling; Jupp, David L. B.; Lovell, Jenny L.; Culvenor, Darius; Newnham, Glenn J.; Richardson, Andrew D.; Ni-Meister, Wenge; Schaaf, Crystal L.; Woodcock, Curtis E.; Strahler, Alan H.

    2011-01-01

    Effective leaf area index (LAI) retrievals from a scanning, ground-based, near-infrared (1064 nm) lidar that digitizes the full return waveform, the Echidna Validation Instrument (EVI), are in good agreement with those obtained from both hemispherical photography and the Li-Cor LAI-2000 Plant Canopy Analyzer. We conducted trials at 28 plots within six stands of hardwoods and conifers of varying height and stocking densities at Harvard Forest, Massachusetts, Bartlett Experimental Forest, New Hampshire, and Howland Experimental Forest, Maine, in July 2007. Effective LAI values retrieved by four methods, which ranged from 3.42 to 5.25 depending on the site and method, were not significantly different ( b0.1 among four methods). The LAI values also matched published values well. Foliage profiles (leaf area with height) retrieved from the lidar scans, although not independently validated, were consistent with stand structure as observed and as measured by conventional methods. Canopy mean top height, as determined from the foliage profiles, deviated from mean RH100 values obtained from the Lidar Vegetation Imaging Sensor (LVIS) airborne large-footprint lidar system at 27 plots by .0.91 m with RMSE=2.04 m, documenting the ability of the EVI to retrieve stand height. The Echidna Validation Instrument is the first realization of the Echidna lidar concept, devised by Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO), for measuring forest structure using full-waveform, ground-based, scanning lidar.

  15. Viewing forests from below: fine root mass declines relative to leaf area in aging lodgepole pine stands.

    PubMed

    Schoonmaker, A S; Lieffers, V J; Landhäusser, S M

    2016-07-01

    In the continued quest to explain the decline in productivity and vigor with aging forest stands, the most poorly studied area relates to root system change in time. This paper measures the wood production, root and leaf area (and mass) in a chronosequence of fire-origin lodgepole pine (Pinus contorta Loudon) stands consisting of four age classes (12, 21, 53, and ≥100 years), each replicated ~ five times. Wood productivity was greatest in the 53-year-old stands and then declined in the ≥100-year-old stands. Growth efficiency, the quantity of wood produced per unit leaf mass, steadily declined with age. Leaf mass and fine root mass plateaued between the 53- and ≥100-year-old stands, but leaf area index actually increased in the older stands. An increase in the leaf area index:fine root area ratio supports the idea that older stand are potentially limited by soil resources. Other factors contributing to slower growth in older stands might be lower soil temperatures and increased self-shading due to the clumped nature of crowns. Collectively, the proportionally greater reduction in fine roots in older stands might be the variable that predisposes these forests to be at a potentially greater risk of stress-induced mortality. PMID:27041684

  16. Application of evidential reasoning to improve the mapping of regenerating forest stands

    NASA Astrophysics Data System (ADS)

    Mora, Brice; Fournier, Richard A.; Foucher, Samuel

    2011-06-01

    This study confirmed the ability of the Dempster-Shafer theory (DST) and the Dezert-Smarandache (Free DSm model) theory to significantly improve the quality of maps of regenerating forest stands in southern Quebec, Canada compared to a classical Maximum Likelihood Algorithm (MLA). The proposed approach uses data fusion methods that allow the integration of remotely sensed imagery with conventional maps of ecophysiographic features. While the MLA provided an overall accuracy of 82.75%, the DST and Free DSm models had overall accuracies of 90.14% and 91.13% respectively. In addition, this study showed that the data fusion methods can model the influence of biophysical parameters (e.g., surface deposits and drainage) on the growth potential of regenerating forest stands. This study illustrates the importance of the mass function allocation for each ancillary data source. We found that a Bayesian belief configuration provided results equivalent to those obtained when representing data uncertainty. This demonstrates the difficulty in modelling uncertainty associated with each ancillary source.

  17. Nitrogen, phosphorus, and cation use efficiency in stands of regenerating tropical dry forest.

    PubMed

    Waring, Bonnie G; Becknell, Justin M; Powers, Jennifer S

    2015-07-01

    Plants on infertile soils exhibit physiological and morphological traits that support conservative internal nutrient cycling. However, potential trade-offs among use efficiencies for N, P, and cations are not well explored in species-rich habitats where multiple elements may limit plant production. We examined uptake efficiency and use efficiency of N, P, K, Ca, Mg, Al, and Na in plots of regenerating tropical dry forests spanning a gradient of soil fertility. Our aim was to determine whether plant responses to multiple elements are correlated, or whether there are trade-offs among exploitation strategies across stands varying in community composition, soil quality, and successional stage. For all elements, both uptake efficiency and use efficiency decreased as availability of the corresponding element increased. Plant responses to N, Na, and Al were uncoupled from uptake and use efficiencies for P and essential base cations, which were tightly correlated. N and P use efficiencies were associated with shifts in plant species composition along the soil fertility gradient, and there was also a trend towards increasing N use efficiency with stand age. N uptake efficiency was positively correlated with the abundance of tree species that associate with ectomycorrhizal fungi. Taken together, our results suggest that successional processes and local species composition interact to regulate plant responses to availability of multiple resources. Successional tropical dry forests appear to employ different strategies to maximize response to N vs. P and K. PMID:25740336

  18. Evaluation of residual stand damage following whole-tree partial cutting in northern forest types

    SciTech Connect

    Cline, M.L. ); Hoffman, B. . Coll. of Forest Resources); Cyr, M. )

    1990-06-01

    A market for low-quality wood chips for biomass boilers in recent years has evoked mixed reactions from both the public and the forestry community. The increased demand for rough, rotten, and cull trees for fuelwood presents opportunities to improve timber stand quality in the Northeast forest. In the past, only the best trees were harvested in the past leaving the poorer quality ones to develop into the next forest, a practice called high-grading. The new market for low-quality wood offers an opportunity to reverse the adverse impacts of high-grading. The present study was designed to quantify the amount of residual stand damage that occurs when whole-trees are harvested during thinning or partial cut operations, and to correlate the extend of damage with several important variables of silvicultural management. A total of 18 hardwood or mixed wood study sites were selected in Maine, New Hampshire, and Vermont that were harvested within the last five years using wheeled, drive-to-bunch harvesting machines.

  19. The role of forest stand density in controlling soil erosion: implications to sediment-related disasters in Japan.

    PubMed

    Razafindrabe, Bam H N; He, Bin; Inoue, Shoji; Ezaki, Tsugio; Shaw, Rajib

    2010-01-01

    The role of forest stand density in controlling soil erosion was investigated in Ehime Prefecture, Japan. The main objective was to compare soil erosion under different forest conditions including forest type, species composition, and stand density as influenced by thinning operations. Relative yield index (Ry) was used as an indicator of stand density to reflect the degree of management operations in the watershed. Eleven treatments were established based on the above forest conditions. Soil loss was collected in each of the 11 treatments after each rainfall event for a period of 1 year. The paper presents summary data on soil loss as affected by forest conditions and rainfall patterns. Findings showed that an appropriate forest management operation, which can be insured by stand density control, is needed to reduce soil loss. The present study plays an important role in clarifying technical processes related to soil erosion, while it helps linking these elements to current Japanese forestry issues and bringing new inputs to reducing sediment-related disasters in Japan. PMID:19105038

  20. Occurrence of spruce bark beetles in forest stands at different levels of air pollution stress.

    PubMed

    Grodzki, Wojciech; McManus, Michael; Knízek, Milos; Meshkova, Valentina; Mihalciuc, Vasile; Novotny, Julius; Turcani, Marek; Slobodyan, Yaroslav

    2004-07-01

    The spruce bark beetle, Ips typographus (L.) is the most serious pest of mature spruce stands, mainly Norway spruce, Picea abies (L.) Karst. throughout Eurasia. A complex of weather-related events and other environmental stresses are reported to predispose spruce stands to bark beetle attack and subsequent tree mortality; however the possible role of industrial pollution as a predisposing factor to attack by this species is poorly understood. The abundance and dynamics of I. typographus populations was evaluated in 60-80 year old Norway spruce stands occurring on 10 x 50 ha sites in five countries within the Carpathian range that were selected in proximity to established ozone measurement sites. Data were recorded on several parameters including the volume of infested trees, captures of adult beetles in pheromone traps, number of attacks, and the presence and relative abundance of associated bark beetle species. In several cases, stands adjacent to sites with higher ozone values were associated with higher bark beetle populations. The volume of sanitary cuttings, a reflection of tree mortality, and the mean daily capture of beetles in pheromone traps were significantly higher at sites where the O(3) level was higher. However, the mean infestation density on trees was higher in plots associated with lower O(3) levels. Captures of beetles in pheromone traps and infestation densities were higher in the zone above 800 m. However, none of the relationships was conclusive, suggesting that spruce bark beetle dynamics are driven by a complex interaction of biotic and abiotic factors and not by a single parameter such as air pollution. PMID:15046842

  1. Salmonberry and salal annual aerial stem production: The maintenance of shrub cover in forest stands

    USGS Publications Warehouse

    Tappeiner, J. C., II; Zasada, J.; Huffman, D.; Ganio, L.

    2001-01-01

    Annual sprouting of aerial stems and ramets enables populations of salmonberry (Rubus spectabilis Pursh), salal (Gaultheria shallon Pursh), and probably other forest shrubs to maintain dense covers (>20 000 stems/ha). We studied annual stem production of salmonberry on cut (all stems cut within 15 cm of the ground) and uncut (stems were not treated) plots for 8 years and salal for 5 years in the understories of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), alder, and riparian stands, as well as clearcuts, which are all common stand types in western Oregon. Mean salmonberry stem production on uncut plots ranged from 4.7 stemsA?ma??2A?yeara??1 (95% CI 2.9a??7.4) in alder stands and clearcuts to 1.6 stemsA?ma??2A?yeara??1 (95% CI 1.0a??2.6) in conifer stands. Mean salal production was greater, ranging from 58 stemsA?ma??2A?yeara??1 (95% CI 25a??135) to 8.6 stemsA?ma??2A?yeara??1 (95% CI 3.7a??20.1) on uncut plots in clearcuts and unthinned Douglas-fir stands, respectively. Annual production of both species was somewhat greater on cut plots. Most stems produced in early spring die by December, but enough are recruited to replace mortality of older stems. Stem density was maintained for 8 years for salmonberry and 5 years for salal on both cut and uncut plots. Based on length of rhizomes and bud density we estimate that only 1a??5% of the buds in the rhizomes are needed to support this annual stem production. Although these species sprout vigorously after their aerial stems are killed, disturbance is not necessary for maintaining a dense cover. It appears that, once established, salal, salmonberry, and probably other clonal forest shrubs can maintain a dense cover that can interfere with establishment of trees and other shrubs in canopy gaps or other openings.

  2. Colville study: Wood utilization for ecosystem management. Preliminary results of study of product potential from small-diameter stands. Forest Service research paper

    SciTech Connect

    Willits, S.; Barbour, R.J.; Tesch, S.; Ryland, D.; McNeel, J.

    1996-12-01

    The Colville Study was developed in 1994 to identify and evaluate a series of management options for achieving ecosystem objectives in dense stands of small diameter trees while also producing wood products. The Colville National Forest selected the Rocky II Timber Sale as an example of this type of stand that needed management to achieve the following goals: (1) create late successional forest structure, (2) decrease forest health risk from fire, insects, and disease, (3) improve wildlife habitat by providing large green trees and snags, and (4) improve stand aesthetics by decreasing stand density. The Colville Study was divided into four technical focus areas: Silviculture and Ecology, Forest Operations, Timber Conversion, and Economics.

  3. Net primary productivity of forest stands in New Hampshire estimated from Landsat and MODIS satellite data

    PubMed Central

    Potter, Christopher; Gross, Peggy; Genovese, Vanessa; Smith, Marie-Louise

    2007-01-01

    Background A simulation model that relies on satellite observations of vegetation cover from the Landsat 7 sensor and from the Moderate Resolution Imaging Spectroradiometer (MODIS) was used to estimate net primary productivity (NPP) of forest stands at the Bartlett Experiment Forest (BEF) in the White Mountains of New Hampshire. Results Net primary production (NPP) predicted from the NASA-CASA model using 30-meter resolution Landsat inputs showed variations related to both vegetation cover type and elevational effects on mean air temperatures. Overall, the highest predicted NPP from the NASA-CASA model was for deciduous forest cover at low to mid-elevation locations over the landscape. Comparison of the model-predicted annual NPP to the plot-estimated values showed a significant correlation of R2 = 0.5. Stepwise addition of 30-meter resolution elevation data values explained no more than 20% of the residual variation in measured NPP patterns at BEF. Both the Landsat 7 and the 250-meter resolution MODIS derived mean annual NPP predictions for the BEF plot locations were within ± 2.5% of the mean of plot estimates for annual NPP. Conclusion Although MODIS imagery cannot capture the spatial details of NPP across the network of closely spaced plot locations as well as Landsat, the MODIS satellite data as inputs to the NASA-CASA model does accurately predict the average annual productivity of a site like the BEF. PMID:17941989

  4. Quantifying Components of Soil Respiration and Their Response to Abiotic Factors in Two Typical Subtropical Forest Stands, Southwest China

    PubMed Central

    Yu, Lei; Wang, Yujie; Wang, Yunqi; Sun, Suqi; Liu, Liziyuan

    2015-01-01

    Separating the components of soil respiration and understanding the roles of abiotic factors at a temporal scale among different forest types are critical issues in forest ecosystem carbon cycling. This study quantified the proportions of autotrophic (RA) and heterotrophic (RH) in total soil (RT) respiration using trenching and litter removal. Field studies were conducted in two typical subtropical forest stands (broadleaf and needle leaf mixed forest; bamboo forest) at Jinyun Mountain, near the Three Georges Reservoir in southwest China, during the growing season (Apr.–Sep.) from 2010 to 2012. The effects of air temperature (AT), soil temperature (ST) and soil moisture (SM) at 6cm depth, solar radiation (SR), pH on components of soil respiration were analyzed. Results show that: 1) SR, AT, and ST exhibited a similar temporal trend. The observed abiotic factors showed slight interannual variability for the two forest stands. 2) The contributions of RH and RA to RT for broadleaf and needle leaf mixed forest were 73.25% and 26.75%, respectively, while those for bamboo forest were 89.02% and 10.98%, respectively; soil respiration peaked from June to July. In both stands, CO2 released from the decomposition of soil organic matter (SOM), the strongest contributor to RT, accounted for over 63% of RH. 3) AT and ST were significantly positively correlated with RT and its components (p<0.05), and were major factors affecting soil respiration. 4) Components of soil respiration were significantly different between two forest stands (p<0.05), indicating that vegetation types played a role in soil respiration and its components. PMID:25680112

  5. Root standing crop and chemistry after six years of soil warming in a temperate forest.

    PubMed

    Zhou, Yumei; Tang, Jianwu; Melillo, Jerry M; Butler, Sarah; Mohan, Jacqueline E

    2011-07-01

    Examining the responses of root standing crop (biomass and necromass) and chemistry to soil warming is crucial for understanding root dynamics and functioning in the face of global climate change. We assessed the standing crop, total nitrogen (N) and carbon (C) compounds in tree roots and soil net N mineralization over the growing season after 6 years of experimental soil warming in a temperate deciduous forest in 2008. Roots were sorted into four different categories: live and dead fine roots (≤1mm in diameter) and live and dead coarse roots (1-4 mm in diameter). Total root standing crop (live plus dead) in the top 10 cm of soil in the warmed area was 42.5% (378.4 vs. 658.5 g m(-2)) lower than in the control area, while live root standing crop in the warmed area was 62% lower than in the control area. Soil net N mineralization over the growing season increased by 79.4% in the warmed relative to the control area. Soil warming did not significantly change the concentrations of C and C compounds (sugar, starch, hemicellulose, cellulose and lignin) in the four root categories. However, total N concentration in the live fine roots in the warmed area was 10.5% (13.7 vs. 12.4 mg g(-1)) higher and C:N ratio was 8.6% (38.5 vs. 42.1) lower than in the control area. The increase in N concentration in the live fine roots could be attributed to the increase in soil N availability due to soil warming. Net N mineralization was negatively correlated with both live and dead fine roots in the mineral soil that is home to the majority of roots, suggesting that soil warming increases N mineralization, decreases fine root biomass and thus decreases C allocation belowground. PMID:21813516

  6. Unravelling the importance of forest age stand and forest structure driving microbiological soil properties, enzymatic activities and soil nutrients content in Mediterranean Spanish black pine(Pinus nigra Ar. ssp. salzmannii) Forest.

    PubMed

    Lucas-Borja, M E; Hedo, J; Cerdá, A; Candel-Pérez, D; Viñegla, B

    2016-08-15

    This study aimed to investigate the effects that stand age and forest structure have on microbiological soil properties, enzymatic activities and nutrient content. Thirty forest compartments were randomly selected at the Palancares y Agregados managed forest area (Spain), supporting forest stands of five ages; from 100 to 80years old to compartments with trees that were 19-1years old. Forest area ranging from 80 to 120years old and without forest intervention was selected as the control. We measured different soil enzymatic activities, soil respiration and nutrient content (P, K, Na, Mg, Cr, Mn, Fe, Co, Ni, Cu, Zn, Pb and Ca) in the top cm of 10 mineral soils in each compartment. Results showed that the lowest forest stand age and the forest structure created by management presented lower values of organic matter, soil moisture, water holding capacity and litterfall and higher values of C/N ratio in comparison with the highest forest stand age and the related forest structure, which generated differences in soil respiration and soil enzyme activities. The forest structure created by no forest management (control plot) presented the highest enzymatic activities, soil respiration, NH4(+) and NO3(-). Results did not show a clear trend in nutrient content comparing all the experimental areas. Finally, the multivariate PCA analysis clearly clustered three differentiated groups: Control plot; from 100 to 40years old and from 39 to 1year old. Our results suggest that the control plot has better soil quality and that extreme forest stand ages (100-80 and 19-1years old) and the associated forest structure generates differences in soil parameters but not in soil nutrient content. PMID:27099995

  7. Ecological stoichiometric characteristics and element reserves of three stands in a closed forest on the Chinese loess plateau.

    PubMed

    Cao, Yuanbo; Wang, Baitian; Wei, Tingting; Ma, Hua

    2016-02-01

    Populus davidiana, Leuchtenbergia principis, and Pinus tabulaeformis are important greening tree species with a cosmopolitan distribution. However, the stoichiometric characteristics and element reserves of stands of these three species are not particularly clear. In this study, we conducted a plot-level investigation of forest stands of these species in the loess area; these have been closed forest stands more than 28 years. Trees were sampled from an area of 50 m × 20 m (in 6, 8, and 9 plots, respectively), which was sufficient for shrub (2 m × 2 m), herbal species, and litter (1 m × 1 m) investigations. The C, N, and P concentrations and the C:N:P stoichiometry in five different soil layers (0-10 cm, 10-20 cm, 20-30 cm, 30-50 cm, and 50-100 cm) and in the leaves, stems, branches, and roots of the plants were examined. The soil element concentrations and density were affected by soil depth. The element content had a significantly negative correlation with soil depth, and element density differed significantly among the soil layers. A particular element in a particular organ differed significantly between the forest stands, and the same element in different organs of the same stand was also significantly different. The C, N, and P element reserves in the soil were considerably higher than in the plants. Our results indicate that there are different stoichiometric characteristics and element reserves of the three stands in a closed forest on the Chinese loess plateau, which may provide a reference when we develop and optimize the structure of forest stands. PMID:26739010

  8. Prevalence of infectious diseases in Bangladeshi women living adjacent to a truck stand: HIV/STD/hepatitis/genital tract infections

    PubMed Central

    Gibney, L.; Macaluso, M.; Kirk, K.; Hassan, M; Schwebke, J.; Vermund, S.; Choudhury, P.

    2001-01-01

    Background: Little is known about infection rates for human immunodeficiency virus (HIV) and other diseases that can be transmitted sexually in Bangladeshi women who may be at intermediate levels of risk—that is, women who are not commercial sex workers (CSWs) but whose sexual contacts may include men at high risk for STD. This study examines HIV/hepatitis/STD and other genital tract infections in women living near Tejgaon truck stand in Dhaka, Bangladesh. Methods: This population based study was conducted from January to December 1998. A random sample of 384 women provided urine and blood samples and participated in an interview; 261 of them also had a physical examination in which vaginal and cervical specimens were taken. Laboratory tests included PCR on urine and cervical swabs for gonorrhoea and chlamydia, culture for trichomoniasis, serology tests for syphilis, herpes simplex 2, hepatitis B, C, D, HIV1, HIV2, and clinical diagnoses of other genital tract infections. Results: None of the participants tested positive for HIV. In the 261 women who had a physical examination, trichomoniasis was detected in 19.5%, chlamydia in 3.4%, gonorrhoea in 5.4%, bacterial vaginosis in 37.2%, and candidiasis in 10%. In the full sample of 384 women, with tests of urine and blood, prevalence of infection with chlamydia, gonorrhoea, syphilis, and herpes simplex 2 was detected in 0%, 6.3%, 5.7%, and 32% respectively. Almost 50% of the subjects had ever been exposed to hepatitis B, 3.6% were currently infective, 1.6% had hepatitis C, and none had hepatitis D. Conclusion: The high prevalence of certain of these infectious diseases indicates the need to implement prevention interventions with these women and, perhaps more importantly, with their male partners. Qualitative research is needed to provide insights into their sexual behaviour and the contexts in which high risk behaviours occur. Key Words: sexually transmitted diseases; Bangladesh; truck drivers PMID:11588280

  9. Roads in northern hardwood forests affect adjacent plant communities and soil chemistry in proportion to the maintained roadside area.

    PubMed

    Neher, Deborah A; Asmussen, David; Lovell, Sarah Taylor

    2013-04-01

    The spatial extent of the transported materials from three road types was studied in forest soil and vegetative communities in Vermont. Hypotheses were two-fold: 1) soil chemical concentrations above background environment would reflect traffic volume and road type (highway>2-lane paved>gravel), and 2) plant communities close to the road and near roads with greater traffic will be disturbance-tolerant and adept at colonization. Soil samples were gathered from 12 randomly identified transects for each of three road types classified as "highway," "two-lane paved," and "gravel." Using GIS mapping, transects were constructed perpendicular to the road, and samples were gathered at the shoulder, ditch, backslope, 10 m from the edge of the forest, and 50 m from road center. Sample locations were analyzed for a suite of soil elements and parameters, as well as percent area coverage by plant species. The main effects from roads depended on the construction modifications required for a roadway (i.e., vegetation clearing and topography modification). The cleared area defined the type of plant community and the distance that road pollutants travel. Secondarily, road presence affected soil chemistry. Metal concentrations (e.g., Pb, Cd, Cu, and Zn) correlated positively with road type. Proximity to all road types made the soils more alkaline (pH 7.7) relative to the acidic soil of the adjacent native forest (pH 5.6). Roadside microtopography had marked effects on the composition of plant communities based on the direction of water flow. Ditch areas supported wetland plant species, greater soil moisture and sulfur content, while plant communities closer to the road were characteristic of drier upland zones. The area beyond the edge of the forest did not appear to be affected chemically or physically by any of the road types, possibly due to the dense vegetation that typically develops outside of the managed right-of-way. PMID:23435063

  10. Forest floor bryophytes of Pseudotsuga menziesii-Tsuga heterophylla stand in Oregon: Influences of substrate and overstory

    USGS Publications Warehouse

    Rambo, T.; Muir, Patricia S.

    1998-01-01

    Species richness and abundance of bryophytes inhabiting forest floor substrates were assessed at two sites in western Oregon. Bryophyte diversity, abundance, and community composition were compared between sites, and between young forest stands (~55 yrs) and old-growth stands (400 + yrs) within each site. Relationships of stand structural features to diversity and community composition were assessed by stratifying sampling between 'diversity' plots placed in areas of greater structural diversity, such as hardwood openings and remnant old-growth trees, and 'matrix' plots situated within the remaining more homogeneous conifer-dominated forest matrix. Richness, particularly for liverworts, was significantly higher in old-growth than young stands, and the two ages differed significantly in community composition. Substrate (ground versus coarse woody debris) and overstory (conifers versus hardwoods) were most strongly correlated with variation in community composition. Relatively open hardwood-dominated diversity plots differed in composition from matrix plots. Bryophyte abundance was lower in denser stands and plots, and positively correlated with canopy gaps, percentage of hardwoods, and incident solar radiation. These results suggest that availability of light may limit bryophyte productivity in these stands.

  11. Use of Seasat satellite radar imagery for the detection of standing water beneath forest vegetation

    NASA Technical Reports Server (NTRS)

    Macdonald, H. C.; Waite, W. P.; Demarcke, J. S.

    1981-01-01

    The Seasat synthetic aperture radar, operating at a 23-cm, L-band wavelength, detected anomalous tonal patterns in areas having relatively uniform vegetable canopy. These anomalously high radar returns were shown to be related more to the underlying terrain (areas of standing water) than to the vegetation canopy. These results show that L-band radars, imaging forested terrain in a Seasat configuration, are sensitive to gross changes in vegetation, and may even penetrate the vegetation canopy, providing an unmistakable radar signature. Properly designed space imaging radar shuttle experiments, using multiple frequency and polarization radars of various depression angles, may provide documentation for a flood-monitoring capability. Height, configuration, and density of the biomass in conjunction with frequency and incidence angle of the imaging system are shown to be important factors in formulating a backscatter model, but the relative significance of each is yet to be determined.

  12. Parametric analysis of synthetic aperture radar data for characterization of deciduous forest stands

    NASA Technical Reports Server (NTRS)

    Wu, Shih-Tseng

    1987-01-01

    The SAR sensor parameters that affect the estimation of deciduous forest stand characteristics were examined using data sets for the Gulf Coastal Plain region, acquired by the NASA/JPL multipolarization airborne SAR. In the regression analysis, the mean digital-number values of the three polarization data are used as the independent variables to estimate the average tree height (HT), basal area (BA), and total-tree biomass (TBM). The following results were obtained: (1) in the case of simple regression and using 28 plots, vertical-vertical (VV) polarization yielded the largest correlation coefficients (r) in estimating HT, BA, and TBM; (2) in the case of multiple regression, the horizontal-horizontal (HH) and VV polarization combination yielded the largest r value in estimating HT, while the VH and HH polarization combination yielded the largest r values in estimating BA and TBM. With the addition of a third polarization, the increase in r values is insignificant.

  13. Simulating boreal forest carbon dynamics after stand-replacing fire disturbance: insights from a global process-based vegetation model

    NASA Astrophysics Data System (ADS)

    Yue, C.; Ciais, P.; Luyssaert, S.; Cadule, P.; Harden, J.; Randerson, J.; Bellassen, V.; Wang, T.; Piao, S. L.; Poulter, B.; Viovy, N.

    2013-04-01

    Stand-replacing fires are the dominant fire type in North American boreal forest and leave a historical legacy of a mosaic landscape of different aged forest cohorts. To accurately quantify the role of fire in historical and current regional forest carbon balance using models, one needs to explicitly simulate the new forest cohort that is established after fire. The present study adapted the global process-based vegetation model ORCHIDEE to simulate boreal forest fire CO2 emissions and follow-up recovery after a stand-replacing fire, with representation of postfire new cohort establishment, forest stand structure and the following self-thinning process. Simulation results are evaluated against three clusters of postfire forest chronosequence observations in Canada and Alaska. Evaluation variables for simulated postfire carbon dynamics include: fire carbon emissions, CO2 fluxes (gross primary production, total ecosystem respiration and net ecosystem exchange), leaf area index (LAI), and biometric measurements (aboveground biomass carbon, forest floor carbon, woody debris carbon, stand individual density, stand basal area, and mean diameter at breast height). The model simulation results, when forced by local climate and the atmospheric CO2 history on each chronosequence site, generally match the observed CO2 fluxes and carbon stock data well, with model-measurement mean square root of deviation comparable with measurement accuracy (for CO2 flux ~100 g C m-2 yr-1, for biomass carbon ~1000 g C m-2 and for soil carbon ~2000 g C m-2). We find that current postfire forest carbon sink on evaluation sites observed by chronosequence methods is mainly driven by historical atmospheric CO2 increase when forests recover from fire disturbance. Historical climate generally exerts a negative effect, probably due to increasing water stress caused by significant temperature increase without sufficient increase in precipitation. Our simulation results demonstrate that a global

  14. Simulating boreal forest carbon dynamics after stand-replacing fire disturbance: insights from a global process-based vegetation model

    NASA Astrophysics Data System (ADS)

    Yue, C.; Ciais, P.; Luyssaert, S.; Cadule, P.; Harden, J.; Randerson, J.; Bellassen, V.; Wang, T.; Piao, S. L.; Poulter, B.; Viovy, N.

    2013-12-01

    Stand-replacing fires are the dominant fire type in North American boreal forests. They leave a historical legacy of a mosaic landscape of different aged forest cohorts. This forest age dynamics must be included in vegetation models to accurately quantify the role of fire in the historical and current regional forest carbon balance. The present study adapted the global process-based vegetation model ORCHIDEE to simulate the CO2 emissions from boreal forest fire and the subsequent recovery after a stand-replacing fire; the model represents postfire new cohort establishment, forest stand structure and the self-thinning process. Simulation results are evaluated against observations of three clusters of postfire forest chronosequences in Canada and Alaska. The variables evaluated include: fire carbon emissions, CO2 fluxes (gross primary production, total ecosystem respiration and net ecosystem exchange), leaf area index, and biometric measurements (aboveground biomass carbon, forest floor carbon, woody debris carbon, stand individual density, stand basal area, and mean diameter at breast height). When forced by local climate and the atmospheric CO2 history at each chronosequence site, the model simulations generally match the observed CO2 fluxes and carbon stock data well, with model-measurement mean square root of deviation comparable with the measurement accuracy (for CO2 flux ~100 g C m-2 yr-1, for biomass carbon ~1000 g C m-2 and for soil carbon ~2000 g C m-2). We find that the current postfire forest carbon sink at the evaluation sites, as observed by chronosequence methods, is mainly due to a combination of historical CO2 increase and forest succession. Climate change and variability during this period offsets some of these expected carbon gains. The negative impacts of climate were a likely consequence of increasing water stress caused by significant temperature increases that were not matched by concurrent increases in precipitation. Our simulation results

  15. Simulating boreal forest carbon dynamics after stand-replacing fire disturbance: insights from a global process-based vegetation model

    USGS Publications Warehouse

    Yue, C.; Ciais, P.; Luyssaert, S.; Cadule, P.; Harden, J.; Randerson, J.; Bellassen, V.; Wang, T.; Piao, S.L.; Poulter, B.; Viovy, N.

    2013-01-01

    Stand-replacing fires are the dominant fire type in North American boreal forests. They leave a historical legacy of a mosaic landscape of different aged forest cohorts. This forest age dynamics must be included in vegetation models to accurately quantify the role of fire in the historical and current regional forest carbon balance. The present study adapted the global process-based vegetation model ORCHIDEE to simulate the CO2 emissions from boreal forest fire and the subsequent recovery after a stand-replacing fire; the model represents postfire new cohort establishment, forest stand structure and the self-thinning process. Simulation results are evaluated against observations of three clusters of postfire forest chronosequences in Canada and Alaska. The variables evaluated include: fire carbon emissions, CO2 fluxes (gross primary production, total ecosystem respiration and net ecosystem exchange), leaf area index, and biometric measurements (aboveground biomass carbon, forest floor carbon, woody debris carbon, stand individual density, stand basal area, and mean diameter at breast height). When forced by local climate and the atmospheric CO2 history at each chronosequence site, the model simulations generally match the observed CO2 fluxes and carbon stock data well, with model-measurement mean square root of deviation comparable with the measurement accuracy (for CO2 flux ~100 g C m−2 yr−1, for biomass carbon ~1000 g C m−2 and for soil carbon ~2000 g C m−2). We find that the current postfire forest carbon sink at the evaluation sites, as observed by chronosequence methods, is mainly due to a combination of historical CO2 increase and forest succession. Climate change and variability during this period offsets some of these expected carbon gains. The negative impacts of climate were a likely consequence of increasing water stress caused by significant temperature increases that were not matched by concurrent increases in precipitation. Our simulation

  16. Simulation of L-band and HH microwave backscattering from coniferous forest stands - A comparison with SIR-B data

    NASA Technical Reports Server (NTRS)

    Sun, Guo-Qing; Simonett, David S.

    1988-01-01

    SIR-B images of the Mt. Shasta region of northern California are used to evaluate a composite L-band HH backscattering model of coniferous forest stands. It is found that both SIR-B and simulated backscattering coefficients for eight stands studied have similar trends and relations to average tree height and average number of trees per pixel. Also, the dispersion and distribution of simulated backscattering coefficients from each stand broadly match SIR-B data from the same stand. Although the limited quality and quantity of experimental data makes it difficult to draw any strong conclusions, the comparisons indicate that a stand-based L-band HH composite model seems promising for explaining backscattering features.

  17. Stand age, tree location and depth impacts on the hydrophobicity of forested dune soils

    NASA Astrophysics Data System (ADS)

    Walsh, Richard; McCreath, Iain; Ogden, Mike; Hallett, Paul

    2015-04-01

    The hydrology of a forest is one of the key mechanisms needed for its productivity. Paradoxically, biomass from forests such as decomposing needles and soil micro-organisms, may result in hydrophobic substances that impede water flow and decrease water retention. At the same time, the decomposition of plant biomass may alter soil pore structure to improve flow and retention of water. Although water repellency has been widely reported in boreal forests, including in unlikely locations in northern maritime climates, the effect of stand age and soil location in relation to trees has not been investigated. In this study it was hypothesised that water repellency would increase with stand age, and would be greater at the interface between the litter layer and soil than in the subsoil or the litter layer itself. Measurements were conducted with soil from Culbin Forest, which is located on the northeast coast of the UK. The forest was planted in phases, starting over 100 years ago, as a means to stabilise eroding sand dunes that were initially highly hydrophilic. Soils were sampled from the litter layer, at the interface between the litter and sand and in the subsoil at locations under the tree, in the drip line and outside of the tree. Field replicated areas planted with Scots Pine in 1888, 1925, 1969, 1992 and 2000 were selected to provide a chronosequence. A series of tests were carried out both in the field and the laboratory to determine the influence that the age of Scots pine trees have on the water repellency of the soil. These included the water drop penetration test and infiltration measurements within the field, while a modified Wilhelmy plate test and capillary rise measurements were measured in the laboratory. The soil was found to possess non-significant water repellency features within the field, likely due to high water content levels of the soil at the time of testing. But after drying, the soil was highly water repellent. The contact angle or repellency

  18. Evaluation of the airborne imaging spectrometer for remote sensing of forest stand conditions

    NASA Technical Reports Server (NTRS)

    Olson, Charles E., Jr.

    1986-01-01

    Five pairs of plots were established in forest stands with one of each pair trenched and covered to prevent precipitation from reaching the tree roots. High winds and falling limbs destroyed the covers on three of the plots. The two remaining plots were in a red pine plantation and in a natural stand of sugar maple. Trees in both plots developed levels of moisture stress more than nine bars higher than control trees on the dates of overflights with the Airborne Imaging Spectrometer (AIS) and the Collins' Airborne Spectroradiometer (CAS). Hemispherical reflectance from stressed and control trees was measured with a Beckman DK2A spectrophotometer. On the day of the AIS overflight, stressed maple foliage was less reflective than the control from 1000 to 1300 nm, but more reflective at wavelengths longer than 1300 nm. Pine foliage was less reflective than the control from 1000 to 1600 nm, but the difference was small at wavelengths longer than 1350 nm. AIS data collected showed brightness values for both maple and pine to be lower than for the controls from 1000 to 1300 nm. CAS data were used to determine the gain in species identification accuracy obtainable with high spectral resolution data.

  19. 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.

  20. Evolutionary feature selection to estimate forest stand variables using LiDAR

    NASA Astrophysics Data System (ADS)

    Garcia-Gutierrez, Jorge; Gonzalez-Ferreiro, Eduardo; Riquelme-Santos, Jose C.; Miranda, David; Dieguez-Aranda, Ulises; Navarro-Cerrillo, Rafael M.

    2014-02-01

    Light detection and ranging (LiDAR) has become an important tool in forestry. LiDAR-derived models are mostly developed by means of multiple linear regression (MLR) after stepwise selection of predictors. An increasing interest in machine learning and evolutionary computation has recently arisen to improve regression use in LiDAR data processing. Although evolutionary machine learning has already proven to be suitable for regression, evolutionary computation may also be applied to improve parametric models such as MLR. This paper provides a hybrid approach based on joint use of MLR and a novel genetic algorithm for the estimation of the main forest stand variables. We show a comparison between our genetic approach and other common methods of selecting predictors. The results obtained from several LiDAR datasets with different pulse densities in two areas of the Iberian Peninsula indicate that genetic algorithms perform better than the other methods statistically. Preliminary studies suggest that a lack of parametric conditions in field data and possible misuse of parametric tests may be the main reasons for the better performance of the genetic algorithm. This research confirms the findings of previous studies that outline the importance of evolutionary computation in the context of LiDAR analisys of forest data, especially when the size of fieldwork datatasets is reduced.

  1. Phosphorus cycling in deciduous forest soil differs between stands dominated by ecto- and arbuscular mycorrhizal trees.

    PubMed

    Rosling, Anna; Midgley, Meghan G; Cheeke, Tanya; Urbina, Hector; Fransson, Petra; Phillips, Richard P

    2016-02-01

    Although much is known about how trees and their associated microbes influence nitrogen cycling in temperate forest soils, less is known about biotic controls over phosphorus (P) cycling. Given that mycorrhizal fungi are instrumental for P acquisition and that the two dominant associations - arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) fungi - possess different strategies for acquiring P, we hypothesized that P cycling would differ in stands dominated by trees associated with AM vs ECM fungi. We quantified soil solution P, microbial biomass P, and sequentially extracted inorganic and organic P pools from May to November in plots dominated by trees forming either AM or ECM associations in south-central Indiana, USA. Overall, fungal communities in AM and ECM plots were functionally different and soils exhibited fundamental differences in P cycling. Organic forms of P were more available in ECM plots than in AM plots. Yet inorganic P decreased and organic P accumulated over the growing season in both ECM and AM plots, resulting in increasingly P-limited microbial biomass. Collectively, our results suggest that P cycling in hardwood forests is strongly influenced by biotic processes in soil and that these are driven by plant-associated fungal communities. PMID:26510093

  2. Nocturnal water loss in mature subalpine Eucalyptus delegatensis tall open forests and adjacent E. pauciflora woodlands

    PubMed Central

    Buckley, Thomas N; Turnbull, Tarryn L; Pfautsch, Sebastian; Adams, Mark A

    2011-01-01

    We measured sap flux (S) and environmental variables in four monospecific stands of alpine ash (Eucalyptus delegatensis R. Baker, AA) and snowgum (E. pauciflora Sieb. ex Spreng., SG) in Australia's Victorian Alps. Nocturnal S was 11.8 ± 0.8% of diel totals. We separated transpiration (E) and refilling components of S using a novel modeling approach based on refilling time constants. The nocturnal fraction of diel water loss (fn) averaged 8.6 ± 0.6% for AA and 9.8 ± 1.7% for SG; fn differed among sites but not species. Evaporative demand (D) was the strongest driver of nocturnal E (En). The ratio En/D (Gn) was positively correlated to soil moisture in most cases, whereas correlations between wind speed and Gn varied widely in sign and strength. Our results suggest (1) the large, mature trees at our subalpine sites have greater fn than the few Australian native tree species that have been studied at lower elevations, (2) AA and SG exhibit similar fn despite very different size and life history, and (3) fn may differ substantially among sites, so future work should be replicated across differing sites. Our novel approach to quantifying fn can be applied to S measurements obtained by any method. PMID:22393512

  3. Viewable Gap Fraction in Forests at the Landscape and Stand Scale near Fraser, Colorado, USA

    NASA Astrophysics Data System (ADS)

    Melloh, R. A.; Woodcock, C. E.; Liu, J. C.; Hardy, J. P.; Koenig, G. G.; Davis, R. E.

    2002-12-01

    The 3-dimensional organization of canopy elements impacts the retrieval of snow and soil properties from remote sensing platforms, and influences the optical and infrared radiative environment within the forest. The number and size of gaps within and between tree crowns determines the type and amount of information that can be obtained remotely. One of the objectives of the NASA-Cold Land Process Experiment is to advance techniques for large-scale observation of hydrologic properties, including water storage and freeze-thaw state. Particular focus is placed on passive and active microwave sensors. The purpose of this paper is to: 1) describe gap fraction distributions and within-stand spatial variation of solar radiation in continuous and discontinuous tree stands in the Fraser Local Observation Site (LSOS), and 2) describe the information content that will be available in landscape scale viewable gap fraction maps (30-m resolution) for intensive study sites (ISA's) near Fraser, Colorado, USA. Hemispherical photographs were taken with a Nikkor 8mm/f2 lens at 20-m grid spacing in the Fraser-LSOS, an area of predominantly Lodgepole Pine (Pinus contorta), and were analyzed with Gap Light Analyzer software. Gap fraction probability distributions were determined for 10 degree zenith angle increments. Maximum mid-day radiation transmittance typically occurs at zenith angles between 51 and 61 degrees during mid to late February and 35 to 50 degrees for late March. The zenith angle ranges of maximum transmittance correspond to gap fraction probability distributions that peak at 0.4 in February, and 0.47 in March. The difference between transmittance into the north-edge and south-edge of clearings is more pronounced in February when mid-day sun angles are lower. Canopy openness at the site ranged from 22 to 60%. Direct transmittance ranged from 9 to 83%, and diffuse transmittance 24 to 81%. Viewable gap fraction is the proportion of the forest floor that can be viewed from

  4. Red-cockaded woodpecker male/female foraging differences in young forest stands.

    SciTech Connect

    Franzreb, Kathleen, E.

    2010-07-01

    ABSTRACT The Red-cockaded Woodpecker (Picoides borealis) is an endangered species endemic to pine (Pinus spp.) forests of the southeastern United States. I examined Red-cockaded Woodpecker foraging behavior to learn if there were male/female differences at the Savannah River Site, South Carolina. The study was conducted in largely young forest stands (,50 years of age) in contrast to earlier foraging behavior studies that focused on more mature forest. The Redcockaded Woodpecker at the Savannah River site is intensively managed including monitoring, translocation, and installation of artificial cavity inserts for roosting and nesting. Over a 3-year period, 6,407 foraging observations covering seven woodpecker family groups were recorded during all seasons of the year and all times of day. The most striking differences occurred in foraging method (males usually scaled [45% of observations] and females mostly probed [47%]),substrate used (females had a stronger preference [93%] for the trunk than males [79%]), and foraging height from the ground (mean 6 SE foraging height was higher for males [11.1 6 0.5 m] than females [9.8 6 0.5 m]). Niche overlap between males and females was lowest for substrate (85.6%) and foraging height (87.8%), and highest for tree species (99.0%), tree condition (98.3%), and tree height (96.4%). Both males and females preferred to forage in older, large pine trees. The habitat available at the Savannah River Site was considerably younger than at most other locations, but the pattern of male/female habitat partitioning observed was similar to that documented elsewhere within the range attesting to the species’ ability to adjust behaviorally.

  5. Effects of Forest Thinning on Snow Accumulation in Lodgepole Pine Stands, Montana, U.S.A.

    NASA Astrophysics Data System (ADS)

    Woods, S.; Ahl, R.; Sappington, J.; McCaughey, W.

    2005-12-01

    Alternative silvicultural treatments such as thinning are being increasingly used to reduce wildfire hazards in forested watersheds, but the hydrologic effects of forest thinning are not well defined. We evaluated the effect of even thinning (SE) and group-retention thinning (SG) treatments, both with 60 % basal area removal, on snow accumulation in Lodgepole pine stands at the Tenderfoot Creek experimental forest, west-central Montana. The snow water equivalent (SWE) close to the seasonal peak was measured at >250 locations in the SE and SG treatments and a control in 2003, 2004 and 2005. Reduced interception in SE resulted in a significant (P < 0.0001), 20 to 35 % increase in SWE relative to the control in 2003 and 2004. In 2005, prolonged high intensity snowfall prior to sampling overwhelmed the canopy interception, so that the SWE in SE was just 9 % greater than the control, and the treatment effect was not significant. In the SG treatment, increased losses due to sublimation from south facing group edges and wind scour losses in the openings offset gains due to reduced interception. Consequently, SG always accumulated significantly less snow than SE (p < 0.0001), and the SG treatment and control means were not significantly different. Differences in snow accumulation between groups and openings meant that the SWE in SG was up to 3 times more variable than in either SE or the control. The contrasting responses in the SE and SG treatments demonstrate that thinning can have substantially different effects on snow accumulation depending on the spatial arrangement of tree removal.

  6. Seed dissemination by frugivorous birds from forest fragments to adjacent pastures on the western slope of Volcán Barva, Costa Rica.

    PubMed

    Barrantes, Gilbert; Pereira, Ana

    2002-06-01

    Logging, cattle raising, and agricultural activities have caused the destruction of most forested areas in Costa Rica. In some middle and highlands the abrupt topography delayed the complete destruction of montane forest. Consequently, some fragments of almost pristine forest remain along streams that run in deep canyons. Frequently, these remnants serve as corridors between larger forested areas and as routes for movement of frugivorous birds. Eighteen bird species, e.g., Turdus plebejus, Elaenia frantzii and Ptilogonys caudatus are common dwellers of forest patches throughout the Pacific slope of the Volcán Barva. These species fly frequently from forest fragments to adjacent pastures. They defected and regurgitated seeds of 28 plant species on stumps scattered on pasture areas. Isolated trees and specially the stumps are suitable microhabitats for germination of seeds and establishment of seedings. PMID:12298287

  7. Effects of Dwarf Mistletoe on Stand Structure of Lodgepole Pine Forests 21-28 Years Post-Mountain Pine Beetle Epidemic in Central Oregon

    PubMed Central

    Agne, Michelle C.; Shaw, David C.; Woolley, Travis J.; Queijeiro-Bolaños, Mónica E.

    2014-01-01

    Lodgepole pine (Pinus contorta) forests are widely distributed throughout North America and are subject to mountain pine beetle (Dendroctonus ponderosae) epidemics, which have caused mortality over millions of hectares of mature trees in recent decades. Mountain pine beetle is known to influence stand structure, and has the ability to impact many forest processes. Dwarf mistletoe (Arceuthobium americanum) also influences stand structure and occurs frequently in post-mountain pine beetle epidemic lodgepole pine forests. Few studies have incorporated both disturbances simultaneously although they co-occur frequently on the landscape. The aim of this study is to investigate the stand structure of lodgepole pine forests 21–28 years after a mountain pine beetle epidemic with varying levels of dwarf mistletoe infection in the Deschutes National Forest in central Oregon. We compared stand density, stand basal area, canopy volume, proportion of the stand in dominant/codominant, intermediate, and suppressed cohorts, average height and average diameter of each cohort, across the range of dwarf mistletoe ratings to address differences in stand structure. We found strong evidence of a decrease in canopy volume, suppressed cohort height, and dominant/codominant cohort diameter with increasing stand-level dwarf mistletoe rating. There was strong evidence that as dwarf mistletoe rating increases, proportion of the stand in the dominant/codominant cohort decreases while proportion of the stand in the suppressed cohort increases. Structural differences associated with variable dwarf mistletoe severity create heterogeneity in this forest type and may have a significant influence on stand productivity and the resistance and resilience of these stands to future biotic and abiotic disturbances. Our findings show that it is imperative to incorporate dwarf mistletoe when studying stand productivity and ecosystem recovery processes in lodgepole pine forests because of its potential to

  8. Influence of disturbance on carbon exchange in a permafrost collapse and adjacent burned forest

    USGS Publications Warehouse

    Myers-Smith, I. H.; McGuire, A.D.; Harden, J.W.; Chapin, F. S., III

    2007-01-01

    We measured CO2 and CH4 exchange from the center of a Sphagnum-dominated permafrost collapse, through an aquatic most, and into a recently burned black spruce forest on the Tanana River floodplain in interior Alaska. In the anomalously dry growing season of 2004, both the collapse and the surrounding burned area were net sink, s for CO2, with a mean daytime net ecosystem exchange of -1.4 ??mol CO2 m-2 s-1, while the moat was a CH4 source with a mean flux of 0.013 ??mol CH4 m-2 s-1. Regression analyses identified temperature as the dominant factor affecting intragrowing season variation in CO2 exchange and soil moisture as the primary control influencing CH4 emissions. CH4 emissions during the wettest portion of the growing season were four times higher than during the driest periods. If temperatures continue to warm, peatlahd vegetation will likely expand with permafrost degradation, resulting in greater carbon accumulation and methane emissions for the landscape as a whole. Copyright 2007 by the American Geophysical Union.

  9. Spatially explicit modeling of 1992-2100 land cover and forest stand age for the conterminous United States

    USGS Publications Warehouse

    Sohl, Terry L.; Sayler, Kristi L.; Bouchard, Michelle; Reker, Ryan R.; Friesz, Aaron M.; Bennett, Stacie L.; Sleeter, Benjamin M.; Sleeter, Rachel R.; Wilson, Tamara; Knuppe, Michelle; Van Hofwegen, Travis

    2014-01-01

    Information on future land-use and land-cover (LULC) change is needed to analyze the impact of LULC change on ecological processes. The U.S. Geological Survey has produced spatially explicit, thematically detailed LULC projections for the conterminous United States. Four qualitative and quantitative scenarios of LULC change were developed, with characteristics consistent with the Intergovernmental Panel on Climate Change (IPCC) Special Report on 5 Emission Scenarios (SRES). The four quantified scenarios (A1B, A2, B1, and B2) served as input to the Forecasting Scenarios of Land-use Change (FORE-SCE) model. Four spatially explicit datasets consistent with scenario storylines were produced for the conterminous United States, with annual LULC maps from 1992 through 2100. The future projections are characterized by a loss of natural land covers in most scenarios, with corresponding expansion of 10 anthropogenic land uses. Along with the loss of natural land covers, remaining natural land covers experience increased fragmentation under most scenarios, with only the B2 scenario remaining relatively stable in both proportion of remaining natural land covers and basic fragmentation measures. Forest stand age was also modeled. By 2100, scenarios and ecoregions with heavy forest cutting have relatively lower mean stand ages compared to those with less 15 forest cutting. Stand ages differ substantially between unprotected and protected forest lands, as well as between different forest classes. The modeled data were compared to the National Land Cover Database (NLCD) and other data sources to assess model characteristics. The consistent, spatially explicit, and thematically detailed LULC projections and the associated forest stand age data layers have been used to analyze LULC impacts on carbon and greenhouse gas fluxes, 20 biodiversity, climate and weather variability, hydrologic change, and other ecological processes.

  10. Spatially explicit modeling of 1992-2100 land cover and forest stand age for the conterminous United States.

    PubMed

    Sohl, Terry L; Sayler, Kristi L; Bouchard, Michelle A; Reker, Ryan R; Friesz, Aaron M; Bennett, Stacie L; Sleeter, Benjamin M; Sleeter, Rachel R; Wilson, Tamara; Soulard, Chris; Knuppe, Michelle; Van Hofwegen, Travis

    2014-07-01

    Information on future land-use and land-cover (LULC) change is needed to analyze the impact of LULC change on ecological processes. The U.S. Geological Survey has produced spatially explicit, thematically detailed LULC projections for the conterminous United States. Four qualitative and quantitative scenarios of LULC change were developed, with characteristics consistent with the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emission Scenarios (SRES). The four quantified scenarios (A1B, A2, B1, and B2) served as input to the forecasting scenarios of land-use change (FORE-SCE) model. Four spatially explicit data sets consistent with scenario storylines were produced for the conterminous United States, with annual LULC maps from 1992 through 2100. The future projections are characterized by a loss of natural land covers in most scenarios, with corresponding expansion of anthropogenic land uses. Along with the loss of natural land covers, remaining natural land covers experience increased fragmentation under most scenarios, with only the B2 scenario remaining relatively stable in both the proportion of remaining natural land covers and basic fragmentation measures. Forest stand age was also modeled. By 2100, scenarios and ecoregions with heavy forest cutting had relatively lower mean stand ages compared to those with less forest cutting. Stand ages differed substantially between unprotected and protected forest lands, as well as between different forest classes. The modeled data were compared to the National Land Cover Database (NLCD) and other data sources to assess model characteristics. The consistent, spatially explicit, and thematically detailed LULC projections and the associated forest stand-age data layers have been used to analyze LULC impacts on carbon and greenhouse gas fluxes, biodiversity, climate and weather variability, hydrologic change, and other ecological processes. PMID:25154094

  11. The process-based stand growth model Formix 3-Q applied in a GIS environment for growth and yield analysis in a tropical rain forest.

    PubMed

    Ditzer, T.; Glauner, R.; Förster, M.; Köhler, P.; Huth, A.

    2000-03-01

    Managing tropical rain forests is difficult because few long-term field data on forest growth and the impact of harvesting disturbance are available. Growth models may provide a valuable tool for managers of tropical forests, particularly if applied to the extended forest areas of up to 100,000 ha that typically constitute the so-called forest management units (FMUs). We used a stand growth model in a geographic information system (GIS) environment to simulate tropical rain forest growth at the FMU level. We applied the process-based rain forest growth model Formix 3-Q to the 55,000 ha Deramakot Forest Reserve (DFR) in Sabah, Malaysia. The FMU was considered to be composed of single and independent small-scale stands differing in site conditions and forest structure. Field data, which were analyzed with a GIS, comprised a terrestrial forest inventory, site and soil analyses (water, nutrients, slope), the interpretation of aerial photographs of the present vegetation and topographic maps. Different stand types were determined based on a classification of site quality (three classes), slopes (four classes), and present forest structure (four strata). The effects of site quality on tree allometry (height-diameter curve, biomass allometry, leaf area) and growth (increment size) are incorporated into Formix 3-Q. We derived allometric relations and growth factors for different site conditions from the field data. Climax forest structure at the stand level was shown to depend strongly on site conditions. Simulated successional pattern and climax structure were compared with field observations. Based on the current management plan for the DFR, harvesting scenarios were simulated for stands on different sites. The effects of harvesting guidelines on forest structure and the implications for sustainable forest management at Deramakot were analyzed. Based on the stand types and GIS analysis, we also simulated undisturbed regeneration of the logged-over forest in the DFR at

  12. Overmature periurban Quercus-Carpinus coppice forests in Austria and Japan: a comparison in view of carbon stocks, stand characteristics and conversion to high forest

    NASA Astrophysics Data System (ADS)

    Bruckman, Viktor; Terada, Toru; Fukuda, Kenji; Yamamoto, Hirokazu; Hochbichler, Eduard

    2016-04-01

    Periurban coppice forests have a long history and tradition in Austria, as well as in Japan. Although developed in a slightly different context, such forests faced nearly the same fate during the last century. While these once served biomass almost exclusively as a feedstock for thermal energy, their significance decreased with the increasing use of fossil fuels and coppice management was consequently abandoned and the area developed, or these forests were converted into high forests with different management aims. This study tries to assess the status of periurban forests that were previously managed as coppice in a comparative approach between Austria and Japan. The focus is stand structure, biomass and C stocks, as well as a comparison with high forest. In Japan, we further directly assessed the consequences of coppice to high forest conversion on soil chemistry. We found remarkable similarities in species distribution and total C stocks. While lower diameter classes are dominated by Carpinus, Quercus is only found in larger diameter classes, indicating the overmature character of both stands due to the lapse from a recognized system of coppice management with occasional fuelwood harvesting in the past decades. Total C stocks are comparable, but SOC is significantly higher in Japanese Andosols. The conversion of coppice to high forest in the 1960's in Japan had a notable impact on soil chemistry. This concerns especially the N cycle and we also observed fewer phenolic compounds in mineral soil after conversion. The authors find that there may be multiple benefits for restoring coppice management to these periurban forests. This includes increased biomass production capabilities and carbon sequestration as well as a better habitat provision and a higher biodiversity.

  13. Calibration and Validation of The Soil Water Balance Model Wave For Forest Stands In Flanders: 1. Experimental Setup

    NASA Astrophysics Data System (ADS)

    Verstraeten, W. W.; Minnaert, M.; Meiresonne, L.; van Slycken, J.; Lust, N.; Muys, B.; Feyen, J.

    Knowledge on hydrology and particularly on water use in forest ecosystems is rather scarce in Flanders. In order to assess the impact of forests in catchment hydrology, a model approach is required based on available or easily measurable parameters on me- teorology, forest patrimonium and soil cover. A pragmatic approach to calculate water use by forests is to implement a soil water balance model, which enables a reasonable estimate of the evapotranspiration (ET) despite of the fragmented forest, and therefore the strong boundary effects, typically for Flanders. The scientific objectives of this project are multiple: the calibration (i) and validation (ii) of the water balance model WAVE (Water and Agrochemicals in soil, crop and Vadose Environment) to calculate indirectly evapotranspiration of forests (for oak, beech, ash, poplar and pine) on 17 in- tensely and extensively sampled plots. Verification of the evapotranspiration from the WAVE-output with sap-flow measurements (iii). Comparison of evapotranspiration of forests to that of pasture and cropland will also be made (iv). Measurements of rainfall, throughfall, stemflow, capillary rise from the groundwater table (possibly recharge), percolation and changes in soil water content are conducted on weekly base, except for winter time (every two weeks). From these water balance terms the forest evapo- transpiration is derived. The Leaf-Area-Index was gained using hemispherical canopy images. This parameter is used for determining the soil evaporation and tree transpi- ration component from the simulated evaptranspiration. Sap-flow measurements are gathered using the Heat Field Deformation Method (Cermàk and Nadezhdina, 1998) in four plots (2 pine stands, popular, beech/oak). The preliminary results of the cal- ibration and validation of the soil water balance model WAVE for forest stands in Flanders are shown in part 2.

  14. Differential response by hardwood and deciduous stands in New England forests to climate change and insect-induced mortality

    NASA Astrophysics Data System (ADS)

    Munger, J. William; Wofsy, Steven C.; Orwig, David A.; Williams, Chris

    2016-04-01

    Forests in the northeastern United States include large areas dominated by mosaics of oak/maple and hemlock stands. Often the hardwood dominated stands include a significant cohort of hemlock saplings. However, long-term survival of hemlock in this region is threatened by Hemlock Wooly Adelgid (HWA), an invasive insect that is fatal to eastern hemlock. The northern limit of HWA is affected in part by winter minimum temperature and warmer winters are enabling northward expansion of HWA infestation. At the Harvard Forest in central Massachusetts, two long-term eddy flux towers are measuring carbon exchange in a >100 year old hardwood stand since 1992 (EMS- Ha1) and in a 100-200 year old hemlock stand (Ha2) since 2004. The flux measurements are complemented by vegetation dynamics plots. Carbon exchange at the two sites has distinctly different seasonality. The hardwood site has a shorter carbon uptake period, but higher peak fluxes, while the hemlock stand has a long carbon uptake period extending from spring thaw until early winter freeze. Some contribution from the evergreen hemlock in the understory is evident before canopy greenup at the EMS tower and spring and fall carbon uptake rates have been increasing and contribute in part to a trend towards larger annual carbon uptake at this site. Carbon uptake by hemlock increases with warmer temperatures in the spring and fall transition. Adelgids have reached the hemlock stand near Ha2 and have been widely distributed in the canopy since spring of 2012. The hemlock canopy in that stand is thinning and net carbon uptake and evapotranspiration have been decreasing since 2012. Adelgids have also been observed in scattered stands near the Ha1 tower, but as of 2015 the trees are still healthy. Because hemlocks stands have different seasonality and provide a distinct soil and sub-canopy light environment, their mortality and replacement by hardwood species will have significant impacts on forest dynamics, carbon balance, and

  15. Stand Structural Controls on Evapotranspiration in Native and Invaded Tropical Montane Cloud Forest in Hawai'i

    NASA Astrophysics Data System (ADS)

    Giambelluca, T. W.; Delay, J. K.; Asner, G. P.; Martin, R. E.; Nullet, M. A.; Huang, M.; Mudd, R. G.; Takahashi, M.

    2008-12-01

    Tropical montane cloud forests (TMCFs) in Hawai'i are important zones of water input and stores of critically important native plant and animal species. Invasion by alien tree species threatens these forests and may alter the hydrological services they provide. At two TMCF sites in Hawai'i, one within native Metrosideros polymorpha forest and the other at a site heavily invaded by Psidium cattleianum, we are conducting measurements of stand-level evapotranspiration (ET), transpiration (using sapflow techniques), energy balance, and related processes. Previously presented results showed that ET as a function of available energy was 27% higher at the invaded site than the native site, with the difference rising to 53% during dry- canopy periods. In this presentation, mechanisms for the observed higher ET rate at the invaded site are explored. The difference in measured xylem flow velocities of native and alien trees cannot explain the observed stand level ET difference. Tree basal area is lower at the invaded site than the native site, again contrary to the ET difference. However, the alien trees have much smaller stem diameters, on average, than the native trees, with little or no heartwood. Hence, the cross-sectional xylem area is much greater in the invaded stand, facilitating higher transpiration rates. These results demonstrate the importance of stand structural controls on ET and raise questions about whether higher ET is a transient feature of the succession or a persistent characteristic of invasive trees.

  16. The influence of mature oak stands and spruce plantations on soil-dwelling click beetles in lowland plantation forests.

    PubMed

    Loskotová, Tereza; Horák, Jakub

    2016-01-01

    Most European forests have been converted into forest plantations that are managed for timber production. The main goal of this paper was to determine the difference between mature native sessile oak (Quercus petraea) stands and non-indigenous Norway spruce (Picea abies) plantations, with respect to communities of Athous click beetles in approximately 6,500 ha of lowland plantation forest area in the Czech Republic. Athous subfuscus was the most abundant and widespread species, followed by A. zebei and A. haemorrhoidalis, while A. vittatus was considered rare. Spatial analysis of environmental variables inside studied patches showed that the species composition of Athous beetles best responded to a 20 m radius surrounding traps. The species' responses to the environment showed that A. vittatus and A. haemorrhoidalis preferred oak stands, while A. zebei and A. subfuscus were associated with spruce plantations. In addition, oak stands showed higher diversity of beetle communities. The studied species are important for their ecosystem services (e.g. predation on pests or bioturbation) and seem to tolerate certain degrees of human disturbances, which is especially beneficial for forest plantations managed for timber production. PMID:26793425

  17. The influence of mature oak stands and spruce plantations on soil-dwelling click beetles in lowland plantation forests

    PubMed Central

    Loskotová, Tereza

    2016-01-01

    Most European forests have been converted into forest plantations that are managed for timber production. The main goal of this paper was to determine the difference between mature native sessile oak (Quercus petraea) stands and non-indigenous Norway spruce (Picea abies) plantations, with respect to communities of Athous click beetles in approximately 6,500 ha of lowland plantation forest area in the Czech Republic. Athous subfuscus was the most abundant and widespread species, followed by A. zebei and A. haemorrhoidalis, while A. vittatus was considered rare. Spatial analysis of environmental variables inside studied patches showed that the species composition of Athous beetles best responded to a 20 m radius surrounding traps. The species’ responses to the environment showed that A. vittatus and A. haemorrhoidalis preferred oak stands, while A. zebei and A. subfuscus were associated with spruce plantations. In addition, oak stands showed higher diversity of beetle communities. The studied species are important for their ecosystem services (e.g. predation on pests or bioturbation) and seem to tolerate certain degrees of human disturbances, which is especially beneficial for forest plantations managed for timber production. PMID:26793425

  18. Douglas-fir forests in the Cascade Mountains of Oregon and Washington: is the abundance of small mammals related to stand age and moisture?

    USGS Publications Warehouse

    Coen, P.S.; Bury, R.B.; Spies, T.A.

    1988-01-01

    Red tree voles (Arborimus longicaudus) were the only small mammal strongly associated with old-growth forests, whereas vagrant shrews (Sorex vagrans) were most abundant in young forests. Pacific marsh shrews (S. bendirii) were most abundant in wet old-growth forests, but abundance of this species in young (wet) forests needs further study. Clearcuts had a mammalian fauna distinct from young forest stands. Abundance of several species was correlated to habitat features unique to naturally regenerated forests, indicated an urgent need to study the long-term effects of forest management to nongame wildlife.

  19. Estimating stand structure using discrete-return lidar: an example from low density, fire prone ponderosa pine forests

    USGS Publications Warehouse

    Hall, S. A.; Burke, I.C.; Box, D. O.; Kaufmann, M. R.; Stoker, Jason M.

    2005-01-01

    The ponderosa pine forests of the Colorado Front Range, USA, have historically been subjected to wildfires. Recent large burns have increased public interest in fire behavior and effects, and scientific interest in the carbon consequences of wildfires. Remote sensing techniques can provide spatially explicit estimates of stand structural characteristics. Some of these characteristics can be used as inputs to fire behavior models, increasing our understanding of the effect of fuels on fire behavior. Others provide estimates of carbon stocks, allowing us to quantify the carbon consequences of fire. Our objective was to use discrete-return lidar to estimate such variables, including stand height, total aboveground biomass, foliage biomass, basal area, tree density, canopy base height and canopy bulk density. We developed 39 metrics from the lidar data, and used them in limited combinations in regression models, which we fit to field estimates of the stand structural variables. We used an information–theoretic approach to select the best model for each variable, and to select the subset of lidar metrics with most predictive potential. Observed versus predicted values of stand structure variables were highly correlated, with r2 ranging from 57% to 87%. The most parsimonious linear models for the biomass structure variables, based on a restricted dataset, explained between 35% and 58% of the observed variability. Our results provide us with useful estimates of stand height, total aboveground biomass, foliage biomass and basal area. There is promise for using this sensor to estimate tree density, canopy base height and canopy bulk density, though more research is needed to generate robust relationships. We selected 14 lidar metrics that showed the most potential as predictors of stand structure. We suggest that the focus of future lidar studies should broaden to include low density forests, particularly systems where the vertical structure of the canopy is important

  20. Change in lignin content during litter decomposition in tropical forest soils (Congo): comparison of exotic plantations and native stands

    NASA Astrophysics Data System (ADS)

    Bernhard-Reversat, France; Schwartz, Dominique

    1997-09-01

    Fast-growing tree plantations are being extended in tropical countries resulting in new forest ecosystems, the functioning of which is yet not well known. In particular, few data are available concerning lignin decay rate. Lignin, nitrogen and tannin contents of fresh and decaying litter were measured in natural rain forest and in planted stands of Eucalyptus hybrids. Acacia mangium and A. auriculiformisin Congo, together with litter-fall and forest-floor accumulation. Lignin evolution in aging litter exhibited different patterns. Lignin was accumulated under Eucalyptus plantation, but disappeared under natural forest, and was intermediate under Acaciaplantations. The relationships with decomposition rates and lignin degradation factors, such as white rot fungi and termites, are also discussed.

  1. Highly stocked coniferous stands on the Olympic Peninsula: chemical composition and implications for harvest strategy. Forest Service research paper

    SciTech Connect

    Little, S.N.; Waddell, D.R.

    1987-10-01

    This report presents an assessment of macronutrients and their distribution within highly stocked, stagnant stands of mixed conifers on the Quilcene Ranger District, Olympic National Forest, northwest Washington. These stands consisted of predominantly three species: western hemlock (Tsuga heterophylla), coast Douglas-fir (Pseudotsuga menzeisii), and western redcedar (Thuja plicata). Preliminary investigation suggests that the living crown contains a small portion of the nutrient capital on the site. Extracting this material from the site during harvest or site preparation should not pose a threat to future production of biomass. Bioassays suggested that no macronutrients were deficient for growth of Douglas-fir seedlings.

  2. Testing a simulation model for reconstruction of prehistoric forest-stand dynamics

    SciTech Connect

    Solomon, A.M.; Delcourt, H.R.; West, D.C.; Blasing, T.J.

    1980-01-01

    Three characteristics of the output of a forest-stand simulation model were matched to pollen records of actual vegetation in central Tennessee. Temporal shifts of individual pollen taxon frequencies were compared to shifts of individual plant species frequencies in simulated biomass for the last 16,000 y. Individual pollen profiles (temporally ordered species frequencies) were also compared to simulated biomass profiles during that period. Modern ratios of pollen to vegetation composition (R values) were compared with those calculated from simulated biomass percentages and fossil pollen percentages. The model output was similar to the comparable characteristics of the pollen record. The model output is therefore a plausible description of vegetation characteristics at the site of pollen deposition in central Tennessee. The model produced information unavailable from other sets of prehistoric data. This information describes the invasion and growth of the yellow-poplar which produces no windborne pollen, and of palynologically indistinguishable oak and pine species. These results suggest that many paleoecological questions can be answered through appropriate simulation modeling studies.

  3. Testing a simulation model for reconstruction of prehistoric forest-stand dynamics*1, *2

    NASA Astrophysics Data System (ADS)

    Solomon, Allen M.; Delcourt, Hazel R.; West, Darrell C.; Blasing, T. J.

    1980-11-01

    Three characteristics of the output of a forest-stand simulation model were matched to pollen records of actual vegetation in central Tennessee. Temporal shifts of individual pollen taxon frequencies were compared to shifts of individual plant species frequencies in simulated biomass for the last 16,000 yr. Individual pollen profiles (temporally ordered species frequencies) were also compared to simulated biomass profiles during that period. Modern ratios of pollen to vegetation composition ( R values) were compared with those calculated from simulated biomass percentages and fossil pollen percentages. The model output was similar to the comparable characteristics of the pollen record. The model output is therefore a plausible description of vegetation characteristics at the site of pollen deposition in central Tennessee. The model produced information unavailable from other sets of prehistoric data. This information describes the invasion and growth of the yellow-poplar which produces no windborne pollen, and of palynologically indistinguishable oak and pine species. These results suggest that many paleoecological questions can be answered through appropriate simulation modeling studies.

  4. Effect of long-term understory prescribed burning on standing and down dead woody material in dry upland oak forests

    USGS Publications Warehouse

    Polo, John A.; Hallgren, S.W.; Leslie,, David M., Jr.

    2013-01-01

    Dead woody material, long ignored or viewed as a nuisance for forest management, has gained appreciation for its many roles in the forest including wildlife habitat, nutrient storage and cycling, energy for trophic webs, protection of soil, fuel for fire and carbon storage. The growing interest in managing dead woody material has created strong demand for greater understanding of factors controlling amounts and turnover. Prescribed burning, an important management tool, may have strong effects of dead woody material given fire’s capacity to create and consume dead woody material. We determined effects of long-term understory prescribed burning on standing and down woody material in upland oak forests in south-central North America. We hypothesized that as frequency of fire increased in these stands the amount of deadwood would decrease and the fine woody material would decrease more rapidly than coarse woody material. The study was conducted in forests dominated by post oak (Quercus stellata) and blackjack oak (Quercus marilandica) in wildlife management areas where understory prescribed burning had been practiced for over 20 years and the range of burn frequencies was 0 (unburned) fires per decade (FPD) to 4.6 FPD. The amount of deadwood was low compared with more productive forests in southeastern North America. The biomass (24.7 Mg ha-1) and carbon stocks (11.7 Mg ha-1) were distributed among standing dead (22%), coarse woody debris (CWD, dia. > 7.5 cm., 12%), fine woody debris (FWD, dia. < 7.5 cm., 23%), and forest floor (43%). There was no evidence that understory prescribed burning influenced the amount and size distribution of standing and down dead woody material. There were two explanations for the lack of a detectable effect. First, a high incidence of severe weather including ice storms and strong winds that produce large amounts of deadwood intermittently in an irregular pattern across the landscape may preclude detecting a strong effect of understory

  5. Assessing stand water use in four coastal wetland forests using sapflow techniques: annual estimates, errors and associated uncertainties

    USGS Publications Warehouse

    Krauss, Ken W.; Duberstein, Jamie A.; Conner, William H.

    2015-01-01

    Forests comprise approximately 37% of the terrestrial land surface and influence global water cycling. However, very little attention has been directed towards understanding environmental impacts on stand water use (S) or in identifying rates of S from specific forested wetlands. Here, we use sapflow techniques to address two separate but linked objectives: (1) determine S in four, hydrologically distinctive South Carolina (USA) wetland forests from 2009–2010 and (2) describe potential error, uncertainty and stand-level variation associated with these assessments. Sapflow measurements were made from a number of tree species for approximately 2–8 months over 2 years to initiate the model, which was applied to canopy trees (DBH > 10–20 cm). We determined that S in three healthy forested wetlands varied from 1.97–3.97 mm day−1 or 355–687 mm year−1 when scaled. In contrast, saltwater intrusion impacted individual tree physiology and size class distributions on a fourth site, which decreased S to 0.61–1.13 mm day−1 or 110–196 mm year−1. The primary sources of error in estimations using sapflow probes would relate to calibration of probes and standardization relative to no flow periods and accounting for accurate sapflow attenuation with radial depth into the sapwood by species and site. Such inherent variation in water use among wetland forest stands makes small differences in S (<200 mm year−1) difficult to detect statistically through modelling, even though small differences may be important to local water cycling. These data also represent some of the first assessments of S from temperate, coastal forested wetlands along the Atlantic coast of the USA.

  6. Catchment streamflow response to climate change conditioned by historic alterations of land-use: forest harvest, succession, and stand conversion.

    NASA Astrophysics Data System (ADS)

    Young, D. A., II; Zegre, N.; Edwards, P.; Strager, M.

    2014-12-01

    Headwater streams provide drinking water for millions of people and serve a significant nexus, contributing to the physical, chemical, and biological integrity of navigable waters. Long-term research sites, such as the Fernow Experimental Forest serve as the regions bellwether for ecological change. Nevertheless, few studies have quantified the long term impacts of forest treatment and climate change on streamflow for the catchments of the Fernow. This study serves this roll by accessing the change in water and energy balance of four catchments (WS-1, WS-4, WS-6, WS-7) subject to forest harvest, natural and suppressed regrowth, and stand conversion. We apply the Budyko framework to quantify the relative contributions of climate and land cover changes on annual streamflow between two time periods and over a five year interval spanning 1951-2011. Based on this analysis land-use, forest succession, and climate change-variability are differentially impacting streamflow. In the two-period analysis climate change is responsible for on average 3 % change in mean annual runoff (MAR). Forest harvest and/or succession caused changes in MAR of -0.8 % to -30.0 %. The Budyko decomposition method applied over five year intervals captured the influence of forest treatment on streamflow well. However, the reference (WS-4) is changing in ways that climate alone cannot describe. Overall, it is important to consider how climate, land-use disturbance, and forest succession corroborate by distinguishing their respective impacts.

  7. A stand-alone tree demography and landscape structure module for Earth system models: integration with global forest data

    NASA Astrophysics Data System (ADS)

    Haverd, V.; Smith, B.; Nieradzik, L. P.; Briggs, P. R.

    2014-02-01

    Poorly constrained rates of biomass turnover are a key limitation of Earth system models (ESM). In light of this, we recently proposed a new approach encoded in a model called Populations-Order-Physiology (POP), for the simulation of woody ecosystem stand dynamics, demography and disturbance-mediated heterogeneity. POP is suitable for continental to global applications and designed for coupling to the terrestrial ecosystem component of any ESM. POP bridges the gap between first generation Dynamic Vegetation Models (DVMs) with simple large-area parameterisations of woody biomass (typically used in current ESMs) and complex second generation DVMs, that explicitly simulate demographic processes and landscape heterogeneity of forests. The key simplification in the POP approach, compared with second-generation DVMs, is to compute physiological processes such as assimilation at grid-scale (with CABLE or a similar land surface model), but to partition the grid-scale biomass increment among age classes defined at sub grid-scale, each subject to its own dynamics. POP was successfully demonstrated along a savanna transect in northern Australia, replicating the effects of strong rainfall and fire disturbance gradients on observed stand productivity and structure. Here, we extend the application of POP to a range of forest types around the globe, employing paired observations of stem biomass and density from forest inventory data to calibrate model parameters governing stand demography and biomass evolution. The calibrated POP model is then coupled to the CABLE land surface model and the combined model (CABLE-POP) is evaluated against leaf-stem allometry observations from forest stands ranging in age from 3 to 200 yr. Results indicate that simulated biomass pools conform well with observed allometry. We conclude that POP represents a preferable alternative to large-area parameterisations of woody biomass turnover, typically used in current ESMs.

  8. Activity and abundance of methane-oxidizing bacteria in secondary forest and manioc plantations of Amazonian Dark Earth and their adjacent soils.

    PubMed

    Lima, Amanda B; Muniz, Aleksander W; Dumont, Marc G

    2014-01-01

    The oxidation of atmospheric CH4 in upland soils is mostly mediated by uncultivated groups of microorganisms that have been identified solely by molecular markers, such as the sequence of the pmoA gene encoding the β-subunit of the particulate methane monooxygenase enzyme. The objective of this work was to compare the activity and diversity of methanotrophs in Amazonian Dark Earth soil (ADE, Hortic Anthrosol) and their adjacent non-anthropic soil. Secondly, the effect of land use in the form of manioc cultivation was examined by comparing secondary forest and plantation soils. CH4 oxidation potentials were measured and the structure of the methanotroph communities assessed by quantitative PCR (qPCR) and amplicon pyrosequencing of pmoA genes. The oxidation potentials at low CH4 concentrations (10 ppm of volume) were relatively high in all the secondary forest sites of both ADE and adjacent soils. CH4 oxidation by the ADE soil only recently converted to a manioc plantation was also relatively high. In contrast, both the adjacent soils used for manioc cultivation and the ADE soil with a long history of agriculture displayed lower CH4 uptake rates. Amplicon pyrosequencing of pmoA genes indicated that USCα, Methylocystis and the tropical upland soil cluster (TUSC) were the dominant groups depending on the site. By qPCR analysis it was found that USCα pmoA genes, which are believed to belong to atmospheric CH4 oxidizers, were more abundant in ADE than adjacent soil. USCα pmoA genes were abundant in both forested and cultivated ADE soil, but were below the qPCR detection limit in manioc plantations of adjacent soil. The results indicate that ADE soils can harbor high abundances of atmospheric CH4 oxidizers and are potential CH4 sinks, but as in other upland soils this activity can be inhibited by the conversion of forest to agricultural plantations. PMID:25374565

  9. Activity and abundance of methane-oxidizing bacteria in secondary forest and manioc plantations of Amazonian Dark Earth and their adjacent soils

    PubMed Central

    Lima, Amanda B.; Muniz, Aleksander W.; Dumont, Marc G.

    2014-01-01

    The oxidation of atmospheric CH4 in upland soils is mostly mediated by uncultivated groups of microorganisms that have been identified solely by molecular markers, such as the sequence of the pmoA gene encoding the β-subunit of the particulate methane monooxygenase enzyme. The objective of this work was to compare the activity and diversity of methanotrophs in Amazonian Dark Earth soil (ADE, Hortic Anthrosol) and their adjacent non-anthropic soil. Secondly, the effect of land use in the form of manioc cultivation was examined by comparing secondary forest and plantation soils. CH4 oxidation potentials were measured and the structure of the methanotroph communities assessed by quantitative PCR (qPCR) and amplicon pyrosequencing of pmoA genes. The oxidation potentials at low CH4 concentrations (10 ppm of volume) were relatively high in all the secondary forest sites of both ADE and adjacent soils. CH4 oxidation by the ADE soil only recently converted to a manioc plantation was also relatively high. In contrast, both the adjacent soils used for manioc cultivation and the ADE soil with a long history of agriculture displayed lower CH4 uptake rates. Amplicon pyrosequencing of pmoA genes indicated that USCα, Methylocystis and the tropical upland soil cluster (TUSC) were the dominant groups depending on the site. By qPCR analysis it was found that USCα pmoA genes, which are believed to belong to atmospheric CH4 oxidizers, were more abundant in ADE than adjacent soil. USCα pmoA genes were abundant in both forested and cultivated ADE soil, but were below the qPCR detection limit in manioc plantations of adjacent soil. The results indicate that ADE soils can harbor high abundances of atmospheric CH4 oxidizers and are potential CH4 sinks, but as in other upland soils this activity can be inhibited by the conversion of forest to agricultural plantations. PMID:25374565

  10. Financial constraints to `sustainable` selective harvesting of forests in the eastern Amazon: Bioeconomic modeling of a forest stand in the state of Para, Brazil. Draft report

    SciTech Connect

    Hardner, J.J.; Rice, R.E.

    1994-06-01

    A key issue in the debate over sustainable forest management is the trade-off between the short-term economic benefits of extracting timber aggressively for commercial sale and the long-term economic and ecological benefits of allowing natural forests to stand. The study presents a general methodology for assessing the feasibility of long-term forest management considering natural timber growth rates, mortality, and changes in timber prices and interest rates. Focusing on a 100-ha stand in the Paragominas region of the Eastern Amazon in the State of Para, Brazil, the study simulates the short-term costs and benefits of various levels of harvesting intensity on trees at various stages of growth, and compares the results with the potential returns on 30-day CDs invested over 25 years to determine the opportunity cost of holding mature stands of commercial trees between cutting cycles. Results show improved financial returns as a function of increasing harvest intensity due to the high discount rate in Brazil.

  11. Remote sensing of boreal forest terrain: Sub-pixel scale mixture analysis of land cover and biophysical parameters at forest stand and regional scales

    NASA Astrophysics Data System (ADS)

    Peddle, Derek Roland

    Increasing concentrations of atmospheric carbon dioxide and other greenhouse gases have focused attention on the global carbon cycle. Predicted climate change scenarios indicate the release of large stores of organic carbon in boreal forest regions could have profound ecological, cultural and economic impacts on agricultural, boreal and Arctic tundra zones. Remote sensing provides the only comprehensive information to monitor such large tracts of land, however, conventional NDVI vegetation index approaches have been shown to be unreliable for extracting required biophysical parameters such as biomass, leaf area index and productivity. In this research. spectral mixture analysis (SMA) and geometric- optical reflectance models provide sub-pixel scale forest information such as sunlit canopy, background and shadow fractions which yield improved biophysical estimates when compared to NDVI. This was validated first for individual forest stands using the NASA C scOVER data set from the Superior National Forest, Minnesota USA. Best results were obtained from shadow function using a spheroid based reflectance model with corrections for mutual shadowing and solar zenith angle variations. Following this, a regional scale methodology was implemented in the Boreal Ecosystem Atmosphere Study (B scOREAS) which coupled canopy reflectance models, spectral mixture analysis, and a powerful evidential reasoning classifier into an integrated, physically based land cover and biophysical algorithm (the M⊕P software package). Field spectrometer data processed to end-member reflectance and stand level tree geometry were input to canopy optical models to produce spectral trajectories of reflectance and forest scene components over a full range of stand densities. These trajectories were input to the new M⊕P software to produce land cover and sub-pixel scale outputs for predicting biophysical parameters. Improved classification accuracies and biophysical estimates were obtained compared

  12. Initial characterization of processes of soil carbon stabilization using forest stand-level radiocarbon enrichment

    SciTech Connect

    Swanston, C W; Torn, M S; Hanson, P J; Southon, J R; Garten, C T; Hanlon, E M; Ganio, L

    2004-01-15

    Although the rates and mechanisms of soil organic matter (SOM) stabilization are difficult to observe directly, radiocarbon has proven an effective tracer of soil C dynamics, particularly when coupled with practical fractionation schemes. To explore the rates of C cycling in temperate forest soils, we took advantage of a unique opportunity in the form of an inadvertent stand-level {sup 14}C-labeling originating from a local industrial release. A simple density fractionation scheme separated SOM into inter-aggregate particulate organic matter (free light fraction, free LF), particulate organic matter occluded within aggregates (occluded LF), and organic matter that is complexed with minerals to form a dense fraction (dense fraction, DF). Minimal agitation and density separation was used to isolate the free LF. The remaining dense sediment was subjected to physical disruption and sonication followed by density separation to separate it into occluded LF and DF. The occluded LF had higher C concentrations and C:N ratios than the free LF, and the C concentration in both light fractions was ten times that of the DF. As a result, the light fractions together accounted for less than 4% of the soil by weight, but contained 40% of the soil C in the 0-15 cm soil increment. Likewise, the light fractions were less than 1% weight of the 15-30 cm increment, but contained more than 35% of the soil C. The degree of SOM protection in the fractions, as indicated by {Delta}{sup 14}C, was different. In all cases the free LF had the shortest mean residence times. A significant depth by fraction interaction for {sup 14}C indicates that the relative importance of aggregation versus organo-mineral interactions for overall C stabilization changes with depth. The rapid incorporation of {sup 14}C label into the otherwise depleted DF shows that this organo-mineral fraction comprises highly stable material as well as more recent inputs.

  13. Initial characterizaiton of processes of soil carbon stabilization using forest stand-level radiocarbon enrichment

    SciTech Connect

    Swanston, Christopher W.; Torn, Margaret S.; Hanson, Paul J.; Southon, John R.; Garten, Charles T.; Hanlon, Erin M.; Ganio, Lisa

    2003-12-01

    Although the rates and mechanisms of soil organic matter (SOM) stabilization are difficult to observe directly, radiocarbon has proven an effective tracer of soil C dynamics, particularly when coupled with practical fractionation schemes. To explore the rates of C cycling in temperate forest soils, we took advantage of a unique opportunity in the form of an inadvertent stand level 14C-labeling originating from a local industrial release. A simple density fractionation scheme separated SOM into interaggregate particulate organic matter (free light fraction, free LF), particulate organic matter occluded within aggregates (occluded LF), and organic matter that is complexed with minerals to form a dense fraction (dense fraction, DF). Minimal agitation and density separation was used to isolate the free LF. The remaining dense sediment was subjected to physical disruption and sonication followed by density separation to separate it into occluded LF and DF. The occluded LF had higher C concentrations and C:N ratios than the free LF, and the C concentration in both light fractions was ten times that of the DF. As a result, the light fractions together accounted for less than 4 percent of the soil by weight, but contained 40 percent of the soil C in the 0 15 cm soil increment. Likewise, the light fractions were less than 1 percent weight of the 15 30 cm increment, but contained more than 35 percent of the soil C. The degree of SOM protection in the fractions, as indicated by D14C, was different. In all cases the free LF had the shortest mean residence times. A significant depth by fraction interaction for 14C indicates that the relative importance of aggregation versus organo-mineral interactions for overall C stabilization changes with depth. The rapid incorporation of 14C label into the otherwise depleted DF shows that this organo-mineral fraction comprises highly stable material as well as more recent inputs.

  14. Modeling the impacts of organic layer depth on forest stand recovery from disturbance in the North American boreal forest

    NASA Astrophysics Data System (ADS)

    Trugman, A. T.; Medvigy, D.; Fenton, N.; Bergeron, Y.

    2014-12-01

    The boreal forest contains over 30 percent of Earth's terrestrial carbon, stored mainly as organic matter in soils. Warming temperatures have decreased the fire return interval at many locations, potentially opening more boreal forest space to early-successional deciduous species. However, previous observational studies have shown that the residual forest organic layer depth after a fire can be directly related to fire severity and that this organic layer depth plays a critical role in determining post-fire secondary succession in the North American boreal forest. In this study, we use a numerical model constrained by field data to evaluate: (1) the extent to which the organic layer inhibits deciduous seedling establishment; (2) whether differences in seedling establishment after mild and severe burns affect mature forest structure and composition on decadal to century time scales. Our modeling experiments were carried out with the Ecosystem Demography model version 2 (ED2) terrestrial biosphere model. ED2 is designed to explicitly track the growth and mortality of individual trees, which compete for light, water, and nutrients using an open nitrogen cycle. Our simulations feature parameterizations for aspen and black spruce species-types as well as a new dynamic soil organic layer module with species-specific litter decay rates. The updated boreal forest model is validated using several datasets across the North American boreal forest that range from daily carbon and energy fluxes to multi-century basal area chronosequences including: (1) sub-daily to monthly eddy covariance measurements taken in Delta Junction, Alaska and Manitoba, Canada; (2) decade-long forest inventory data from the Cooperative Alaska Forest Inventory taken throughout the Alaskan boreal forest; and (3) multi-century basal area chronosequences measured in Manitoba and Quebec. We then use the model to identify the controls that the soil organic layer exerts on secondary succession between aspen

  15. Habitat Preferences of Boros schneideri (Coleoptera: Boridae) in the Natural Tree Stands of the Białowieża Forest

    PubMed Central

    Gutowski, Jerzy M.; Sućko, Krzysztof; Zub, Karol; Bohdan, Adam

    2014-01-01

    We analyzed habitat requirements of Boros schneideri (Panzer, 1796) (Coleoptera: Boridae) in the natural forests of the continental biogeographical region, using data collected in the Białowieża Forest. This species has been found on the six host trees, but it preferred dead, standing pine trees, characterized by large diameter, moderately moist and moist phloem but avoided trees in sunny locations. It occurred mostly in mesic and wet coniferous forests. This species demonstrated preferences for old tree stands (over 140-yr old), and its occurrence in younger tree-stand age classes (minimum 31–40-yr old) was not significantly different from random distribution. B. schneideri occupied more frequently locations distant from the forest edge, which were less affected by logging. Considering habitat requirements, character of occurrence, and decreasing number of occupied locations in the whole range of distribution, this species can be treated as relict of primeval forests. PMID:25527586

  16. Four centuries of soil carbon and nitrogen change after stand-replacing fire in a forest landscape in the western Cascade Range of Oregon

    USGS Publications Warehouse

    Giesen, T.W.; Perakis, S.S.; Cromack, K., Jr.

    2008-01-01

    Episodic stand-replacing wildfire is a significant disturbance in mesic and moist Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forests of the Pacific Northwest. We studied 24 forest stands with known fire histories in the western Cascade Range in Oregon to evaluate long-term impacts of stand-replacing wildfire on carbon (C) and nitrogen (N) pools and dynamics within the forest floor (FF, Oe and Oa horizons) and the mineral soil (0-10 cm). Twelve of our stands burned approximately 150 years ago ('young'), and the other 12 burned approximately 550 years ago ('old'). Forest floor mean C and N pools were significantly greater in old stands than young stands (N pools: 1823 ?? 132 kg??ha-1 vs. 1450 ?? 98 kg??ha -1; C pools: 62 980 ?? 5403 kg??ha-1 vs. 49 032 ?? 2965 kg??ha-1, mean ?? SE) as a result of significant differences in FF mass. Forest floor C and N concentrations and C/N ratios did not differ by time since fire, yet potential N mineralization rates were significantly higher in FF of old sites. Old and young mineral soils did not differ significantly in pools, concentrations, C/N ratios, or cycling rates. Our results suggest that C and N are sequestered in FF of Pacific Northwest Douglas-fir forests over long (???400 year) intervals, but that shorter fire return intervals may prevent that accumulation. ?? 2008 NRC.

  17. Impacts of Sedimentation from Oil and Gas Development on Stream Macroinvertebrates in Two Adjacent Watersheds of the Allegheny National Forest of Northwestern Pennsylvania

    SciTech Connect

    Fritz, K.; Harris, S.; Edenborn, H.M.; Sams, J.

    2011-01-01

    Fritz, Kelley'*, Steven Harris', Harry Edenborn2, and James Sams2. 'Clarion University of Pennsylvania, Clarion, PA 16214, 2National Energy Technology Laboratory, U.S. Dept. Energy, Pittsburgh, PA 15236. Impacts a/Sedimentation/rom Oil and Gas Development on Stream Macroinvertebrates in Two Adjacent Watersheds a/the Allegheny National Forest a/Northwestern Pennsylvania - The Allegheny National Forest (ANF), located in northwestern Pennsy Ivania, is a multiuse forest combining commercial development with recreational and conservation activities. As such, portions of the ANF have been heavily logged and are now the subject of widespread oil and gas development. This rapid increase in oil and gas development has led to concerns about sediment runoff from the dirt and gravel roads associated with development and the potential impact on the aquatic biota of the receiving streams. We examined and compared the benthic macroinvertebrate communities in two adjacent watersheds of similar size and topography in the ANF; the Hedgehog Run watershed has no oil and gas development, while the adjacent Grunder Run watershed has extensive oil and gas development. In Hedgehog and Grunder Run, we collected monthly kicknet samples from riffles and glides at two sites from April to October 2010. At the same intervals, we measured standard water quality parameters, including conductivity and turbidity. Preliminary results have indicated much higher turbidity in Grunder Run, but little difference in the diversity and abundance of benthic macro invertebrates inhabiting the two streams.

  18. Above-ground sulfur cycling in adjacent coniferous and deciduous forest and watershed sulfur retention in the Georgia Piedmont, U.S.A.

    USGS Publications Warehouse

    Cappellato, R.; Peters, N.E.; Meyers, T.P.

    1998-01-01

    Atmospheric deposition and above-ground cycling of sulfur (S) were evaluated in adjacent deciduous and coniferous forests at the Panola Mountain Research Watershed (PMRW), Georgia U.S.A. Total atmospheric S deposition (wet plus dry) was 12.9 and 12.7 kg ha-1 yr-1 for the deciduous and coniferous forests, respectively, from October 1987 through November 1989. Dry deposition contributes more than 40% to the total atmospheric S deposition, and SO2 is the major source (~55%) of total dry S deposition. Dry deposition to these canopies is similar to regional estimates suggesting that 60-km proximity to emission sources does not noticeably impact dry deposition at PMRW. Below-canopy S fluxes (throughfall plus stemflow) in each forest are 37% higher annually in the deciduous forest than in the coniferous forest. An excess in below-canopy S flux in the deciduous forest is attributed to leaching and higher dry deposition than in the coniferous forest. Total S deposition to the forest floor by throughfall, stemflow and litterfall was 2.4 and 2.8 times higher in the deciduous and coniferous forests, respectively, than annual S growth requirement for foliage and wood. Although A deposition exceeds growth requirement, more than 95% of the total atmospheric S deposition was retained by the watershed in 1988 and 1989. The S retention at PMRW is primarily due to SO2+4 adsorption by iron oxides and hydroxides in watershed soils. The S content in while oak and loblolly pine boles have increased more than 200% in the last 20 yr, possibly reflecting increases in emissions.

  19. Trace gas emissions from a chronosequence of bark beetle-infested lodgepole pine (Pinus contorta) forest stands

    NASA Astrophysics Data System (ADS)

    Norton, U.; Pendall, E.; Ewers, B. E.; Borkhuu, B.

    2011-12-01

    Severe outbreak of mountain pine beetle (MPB) and associated blue stain fungi have killed millions of hectares of coniferous forests in Western North America. This unprecedented disturbance has critically impacted ecosystem biogeochemistry and net carbon (C) and nitrogen (N) fluxes. However, the effects on greenhouse gas (GHG) emissions and drivers of biogeochemical processes that trigger GHG emissions following MPB infestations are not well understood. Such information can help assess regional-level changes in ecosystem C and N budgets and large-scale disturbance impacts on gas exchange between the atmosphere and terrestrial ecosystem. The overall objective of this research was to assess the immediate responses of GHG fluxes and soil C and N mineralization rates along a chronosequence of recently infested (1-yr, 3-yr and 4-yr ago) and uninfested (150-yr, 20-yr and 15-yr old) lodgepole pine stands in Medicine Bow National Forest in southeastern Wyoming. We hypothesize that MPB-induced tree mortality significantly changes stand-level hydrology, soil organic matter quality and chemistry of aboveground and belowground plant inputs. Consequently, these modifications influence nitrous oxide (N2O) emissions and methane (CH4) assimilation. Biweekly GHG measurements using static chambers were carried out during three consecutive snow-free growing seasons. Our results suggest that a stand infested within a year already shows a 20% increase in spring N2O production and a small decline in summer CH4 assimilation when compared to uninfested stands. Stands infested three and four years prior to our measurements produce over three times more N2O and assimilate three to five times less CH4 when compared to uninfested stands. In addition, a notable increase in soil moisture content and soil mineral N concentrations following early onset of the MPB infestation was also observed. An overall increase in N2O production and decline in CH4 assimilation following MPB infestation may

  20. Rapid rebound of soil respiration following partial stand disturbance by tree girdling in a temperate deciduous forest.

    PubMed

    Levy-Varon, Jennifer H; Schuster, William S F; Griffin, Kevin L

    2014-04-01

    Forests serve an essential role in climate change mitigation by removing CO2 from the atmosphere. Within a forest, disturbance events can greatly impact C cycling and subsequently influence the exchange of CO2 between forests and the atmosphere. This connection makes understanding the forest C cycle response to disturbance imperative for climate change research. The goal of this study was to examine the temporal response of soil respiration after differing levels of stand disturbance for 3 years at the Black Rock Forest (southeastern NY, USA; oaks comprise 67% of the stand). Tree girdling was used to mimic pathogen attack and create the following treatments: control, girdling all non-oaks (NOG), girdling half of the oak trees (O50), and girdling all the oaks (OG). Soil respiratory rates on OG plots declined for 2 years following girdling before attaining a full rebound of belowground activity in the third year. Soil respiration on NOG and O50 were statistically similar to the control for the duration of the study although a trend for a stronger decline in respiration on O50 relative to NOG occurred in the first 2 years. Respiratory responses among the various treatments were not proportional to the degree of disturbance and varied over time. The short-lived respiratory response on O50 and OG suggests that belowground activity is resilient to disturbance; however, sources of the recovered respiratory flux on these plots are likely different than they were pre-treatment. The differential taxon response between oaks and non-oaks suggests that after a defoliation or girdling event, the temporal response of the soil respiratory flux may be related to the C allocation pattern of the affected plant group. PMID:24337785

  1. Influence of forest stands on soil and ecosystem carbon stocks in the conditions of the European part of Russia

    NASA Astrophysics Data System (ADS)

    Kaganov, Vladimir

    2016-04-01

    Forest stands are one of the most important components of ecosystems, both in Russia and around the world and at the same time forest vegetation is able to provide environment-modifying effect on the occupied landscape and, in particular, on the soil cover. Currently, due to the large interest in the carbon cycle, there is a question about the influence of forest vegetation on carbon stocks in ecosystems and in particular in the soil cover. To perform the study we selected 9 objects located in the European part of Russia from the area of the southern taiga to the semi-desert zone: Novgorod region, Kostroma region, Moscow region (2 objects), Penza region, Voronezh region, Volgograd region (2 objects) and Astrakhan region. For studying the influence of forest vegetation on the soil`s carbon, we organized the following experiment scheme: in each of the objects two key sites were selected, so that they originally were in the same soil conditions and the difference between them was only in a course development of vegetation - forest or grass. One part of the experimental sites, presenting forest vegetation, were the restored forests on abandoned lands with the age of 70-200 years. The second part of the experimental sites were artificial forest plantations aged from 60 to 112 years planted on the originally treeless forest-steppe or steppe landscapes. Perennial hayfields, perennial abandoned agricultural landscapes and virgin steppe areas were used as reference sites with grass vegetation. For each forest site we estimated the major carbon pools: phytomass, mortmass (dead wood, dry grass), debris, litter and soil. All data were recalculated using the conversion factors in carbon stocks in t C ha-1. We collected soil samples every 10 cm until the depth of 50 cm, and then at 50-75 and 75-100 cm soil layers. Bulk density and total organic carbon were determined by CHN analyzer. As a result, the soil`s carbon was also calculated into t C ha-1. We found out that the total

  2. Comparative resistance and resilience of soil microbial communities and enzyme activities in adjacent native forest and agricultural soils.

    PubMed

    Chaer, Guilherme; Fernandes, Marcelo; Myrold, David; Bottomley, Peter

    2009-08-01

    Degradation of soil properties following deforestation and long-term soil cultivation may lead to decreases in soil microbial diversity and functional stability. In this study, we investigated the differences in the stability (resistance and resilience) of microbial community composition and enzyme activities in adjacent soils under either native tropical forest (FST) or in agricultural cropping use for 14 years (AGR). Mineral soil samples (0 to 5 cm) from both areas were incubated at 40 degrees C, 50 degrees C, 60 degrees C, or 70 degrees C for 15 min in order to successively reduce the microbial biomass. Three and 30 days after the heat shocks, fluorescein diacetate (FDA) hydrolysis, cellulase and laccase activities, and phospholipid-derived fatty acids-based microbial community composition were measured. Microbial biomass was reduced up to 25% in both soils 3 days after the heat shocks. The higher initial values of microbial biomass, enzyme activity, total and particulate soil organic carbon, and aggregate stability in the FST soil coincided with higher enzymatic stability after heat shocks. FDA hydrolysis activity was less affected (more resistance) and cellulase and laccase activities recovered more rapidly (more resilience) in the FST soil relative to the AGR counterpart. In the AGR soil, laccase activity did not show resilience to any heat shock level up to 30 days after the disturbance. Within each soil type, the microbial community composition did not differ between heat shock and control samples at day 3. However, at day 30, FST soil samples treated at 60 degrees C and 70 degrees C contained a microbial community significantly different from the control and with lower biomass regardless of high enzyme resilience. Results of this study show that deforestation followed by long-term cultivation changed microbial community composition and had differential effects on microbial functional stability. Both soils displayed similar resilience to FDA hydrolysis, a

  3. Ecosystem-scale biosphere-atmosphere interactions of a hemiboreal mixed forest stand at Järvselja, Estonia

    PubMed Central

    Noe, Steffen M.; Kimmel, Veljo; Hüve, Katja; Copolovici, Lucian; Portillo-Estrada, Miguel; Püttsepp, Ülle; Jõgiste, Kalev; Niinemets, Ülo; Hörtnagl, Lukas; Wohlfahrt, Georg

    2013-01-01

    During two measurement campaigns, from August to September 2008 and 2009, we quantified the major ecosystem fluxes in a hemiboreal forest ecosystem in Järvselja, Estonia. The main aim of this study was to separate the ecosystem flux components and gain insight into the performance of a multi-species multi-layered tree stand. Carbon dioxide and water vapor fluxes were measured using the eddy covariance method above and below the canopy in conjunction with the microclimate. Leaf and soil contributions were quantified separately by cuvette and chamber measurements, including fluxes of carbon dioxide, water vapor, nitrogen oxides, nitrous oxide, methane, ozone, sulfur dioxide, and biogenic volatile organic compounds (isoprene and monoterpenes). The latter have been as well characterized for monoterpenes in detail. Based on measured atmospheric trace gas concentrations, the flux tower site can be characterized as remote and rural with low anthropogenic disturbances. Our results presented here encourage future experimental efforts to be directed towards year round integrated biosphere-atmosphere measurements and development of process-oriented models of forest-atmosphere exchange taking the special case of a multi-layered and multi-species tree stand into account. As climate change likely leads to spatial extension of hemiboreal forest ecosystems a deep understanding of the processes and interactions therein is needed to foster management and mitigation strategies. PMID:24347809

  4. Allometric Scaling and Resource Limitations Model of Total Aboveground Biomass in Forest Stands: Site-scale Test of Model

    NASA Astrophysics Data System (ADS)

    CHOI, S.; Shi, Y.; Ni, X.; Simard, M.; Myneni, R. B.

    2013-12-01

    Sparseness in in-situ observations has precluded the spatially explicit and accurate mapping of forest biomass. The need for large-scale maps has raised various approaches implementing conjugations between forest biomass and geospatial predictors such as climate, forest type, soil property, and topography. Despite the improved modeling techniques (e.g., machine learning and spatial statistics), a common limitation is that biophysical mechanisms governing tree growth are neglected in these black-box type models. The absence of a priori knowledge may lead to false interpretation of modeled results or unexplainable shifts in outputs due to the inconsistent training samples or study sites. Here, we present a gray-box approach combining known biophysical processes and geospatial predictors through parametric optimizations (inversion of reference measures). Total aboveground biomass in forest stands is estimated by incorporating the Forest Inventory and Analysis (FIA) and Parameter-elevation Regressions on Independent Slopes Model (PRISM). Two main premises of this research are: (a) The Allometric Scaling and Resource Limitations (ASRL) theory can provide a relationship between tree geometry and local resource availability constrained by environmental conditions; and (b) The zeroth order theory (size-frequency distribution) can expand individual tree allometry into total aboveground biomass at the forest stand level. In addition to the FIA estimates, two reference maps from the National Biomass and Carbon Dataset (NBCD) and U.S. Forest Service (USFS) were produced to evaluate the model. This research focuses on a site-scale test of the biomass model to explore the robustness of predictors, and to potentially improve models using additional geospatial predictors such as climatic variables, vegetation indices, soil properties, and lidar-/radar-derived altimetry products (or existing forest canopy height maps). As results, the optimized ASRL estimates satisfactorily

  5. Bat activity in harvested and intact forest stands in the allegheny mountains

    USGS Publications Warehouse

    Owen, S.F.; Menzel, M.A.; Edwards, J.W.; Ford, W.M.; Menzel, J.M.; Chapman, B.R.; Wood, P.B.; Miller, K.V.

    2004-01-01

    We used Anabat acoustical monitoring devices to examine bat activity in intact canopy forests, complex canopy forests with gaps, forests subjected to diameter-limit harvests, recent deferment harvests, clearcuts and unmanaged forested riparian areas in the Allegheny Mountains of West Virginia in the summer of 1999. We detected eight species of bats, including the endangered Indiana bat (Myotis sodalis). Most bat activity was concentrated in forested riparian areas. Among upland habitats, activity of silver-haired bats (Lasionycteris noctivagans) and hoary bats (Lasiurus cinereus) was higher in open, less cluttered vegetative types such as recent deferment harvests and clearcuts. Our results suggest that bat species in the central Appalachians partially segregate themselves among vegetative conditions based on differences in body morphology and echolocation call characteristics. From the standpoint of conserving bat foraging habitat for the maximum number of species in the central Appalachians, special emphasis should be placed on protecting forested riparian areas.

  6. Species and stand traits of broadleaf deciduous and evergreen trees and its role on hydrologic processes in a semiarid forest

    NASA Astrophysics Data System (ADS)

    Arredondo, T.; Perez Suarez, M.; Rodriguez Robles, U.

    2013-05-01

    Empirical and modelling studies have pointed out to the importance of morphologic, physiologic and chemical traits of plant species on the control of functional aspects of ecosystems. Land use change exerts a pervasive effect on ecosystems through its effects on plant cover, species composition and the arrangement of vegetation. Species footprint influence on ecosystem processes occurs through their functional plant traits, understanding their role might be possible to predict alterations in ecosystem functioning. Using the concept of functional matrix we examined how traits of two dominant forest species, one broadleaf (Quercus potosina) and one evergreen (Pinus cembroides) observed as mixed and monospecific stands, exerted an influence on ecohydrological processes. Thus, differences in plant height, canopy structure, litter production and quality, root system distribution, etc. determined differences in vertical and horizontal rain fluxes. Oak monospecif stands showed 20% higher throughfall compared to mixex and pure pine stands as a consequence of exhibiting a monolayered canopy. On the other hand, runoff was 67 and 33 % in pine compared to oak and mixed stands a result that arosing from observed differences in litter decomposition stage as well as its proportion. Differences between root systems accounted for less negative plant water potentials in oak in contrast to pine. These differences together with leaf phenology allowed oak trees to reduce the plant water potential during the drought period. Similar pattern observed for pine is attributed to foraging capabilities of an extensive root system.

  7. Integrating Stand and Soil Properties to Understand Foliar Nutrient Dynamics during Forest Succession Following Slash-and-Burn Agriculture in the Bolivian Amazon

    PubMed Central

    Broadbent, Eben N.; Almeyda Zambrano, Angélica M.; Asner, Gregory P.; Soriano, Marlene; Field, Christopher B.; de Souza, Harrison Ramos; Peña-Claros, Marielos; Adams, Rachel I.; Dirzo, Rodolfo; Giles, Larry

    2014-01-01

    Secondary forests cover large areas of the tropics and play an important role in the global carbon cycle. During secondary forest succession, simultaneous changes occur among stand structural attributes, soil properties, and species composition. Most studies classify tree species into categories based on their regeneration requirements. We use a high-resolution secondary forest chronosequence to assign trees to a continuous gradient in species successional status assigned according to their distribution across the chronosequence. Species successional status, not stand age or differences in stand structure or soil properties, was found to be the best predictor of leaf trait variation. Foliar δ13C had a significant positive relationship with species successional status, indicating changes in foliar physiology related to growth and competitive strategy, but was not correlated with stand age, whereas soil δ13C dynamics were largely constrained by plant species composition. Foliar δ15N had a significant negative correlation with both stand age and species successional status, – most likely resulting from a large initial biomass-burning enrichment in soil 15N and 13C and not closure of the nitrogen cycle. Foliar %C was neither correlated with stand age nor species successional status but was found to display significant phylogenetic signal. Results from this study are relevant to understanding the dynamics of tree species growth and competition during forest succession and highlight possibilities of, and potentially confounding signals affecting, the utility of leaf traits to understand community and species dynamics during secondary forest succession. PMID:24516525

  8. Integrating stand and soil properties to understand foliar nutrient dynamics during forest succession following slash-and-burn agriculture in the Bolivian Amazon.

    PubMed

    Broadbent, Eben N; Almeyda Zambrano, Angélica M; Asner, Gregory P; Soriano, Marlene; Field, Christopher B; de Souza, Harrison Ramos; Peña-Claros, Marielos; Adams, Rachel I; Dirzo, Rodolfo; Giles, Larry

    2014-01-01

    Secondary forests cover large areas of the tropics and play an important role in the global carbon cycle. During secondary forest succession, simultaneous changes occur among stand structural attributes, soil properties, and species composition. Most studies classify tree species into categories based on their regeneration requirements. We use a high-resolution secondary forest chronosequence to assign trees to a continuous gradient in species successional status assigned according to their distribution across the chronosequence. Species successional status, not stand age or differences in stand structure or soil properties, was found to be the best predictor of leaf trait variation. Foliar δ(13)C had a significant positive relationship with species successional status, indicating changes in foliar physiology related to growth and competitive strategy, but was not correlated with stand age, whereas soil δ(13)C dynamics were largely constrained by plant species composition. Foliar δ(15)N had a significant negative correlation with both stand age and species successional status, - most likely resulting from a large initial biomass-burning enrichment in soil (15)N and (13)C and not closure of the nitrogen cycle. Foliar %C was neither correlated with stand age nor species successional status but was found to display significant phylogenetic signal. Results from this study are relevant to understanding the dynamics of tree species growth and competition during forest succession and highlight possibilities of, and potentially confounding signals affecting, the utility of leaf traits to understand community and species dynamics during secondary forest succession. PMID:24516525

  9. Fate of spinosad in litter and soils of a mixed conifer stand in the Acadian forest region of New Brunswick.

    PubMed

    Thompson, Dean G; Harris, Brenda J; Lanteigne, Leonard J; Buscarini, Teresa M; Chartrand, Derek T

    2002-02-13

    Spinosad is a natural insecticide, produced via fermentation culture of the actinomycete Saccharopolyspora spinosa, with potential use against a number of forest pests including spruce budworm (Choristoneura fumiferana [Clem]). Persistence of spinosad was determined in terrestrial fate experiments conducted within a semimature stand of black spruce (Picea mariana [Mill.]) and balsam fir (Abies balsamea [L]) in the Acadian forest region of New Brunswick, Canada. Results of experiments established under full coniferous canopy and in a canopy opening indicated that spinosad dissipated rapidly following hyperbolic kinetics in both litter and soils and was not susceptible to leaching. Time to 50% dissipation estimates for spinosyn A ranged from 2.0 to 12.4 days depending upon matrix and experimental conditions. Spinosyn D dissipated to levels below quantitation limits (0.02 microg/g of dry mass) within 7 days in all cases. Sporadic low-level detection of the demethylated metabolites suggested that parent compounds were degraded in situ. PMID:11829646

  10. Guide to the stand-damage model interface management system. Forest Service general technical report (Final)

    SciTech Connect

    Racin, G.; Colbert, J.J.

    1995-08-16

    Describes the Gypsy Moth Stand-Damage interface management system. Management of stand-damage data made it necessary to define structures to store data and provide the mechanisms to manipulate these data. The software is used to manipulate files, graph and manage outputs, and edit input data. The interface was built using pop-up windows, menuing systems, text editing and validation, mouse support, and context-sensitive help. The interface is written in the C language for DOS microcomputers.

  11. 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.

  12. Detection of spatio-temporal changes of Norway spruce forest stands in Ore Mountains using airborne hyperspectral imagery

    NASA Astrophysics Data System (ADS)

    Misurec, J.; Kopačková, V.; Lhotáková, Z.; Albrechtova, J.; Campbell, P. K. E.

    2015-12-01

    The Ore Mountains are an example of the region that suffered from severe environmental pollution caused by long-term coal mining and heavy industry leading to massive dieback of the local Norway spruce forests between the 1970's and 1990's. The situation became getting better at the end of 1990's after pollution loads significantly decreased. In 1998 and 2013, airborne hyperspectral data (with sensor ASAS and APEX, respectively) were used to study recovery of the originally damaged forest stands and compared them with those that have been less affected by environmental pollution. The field campaign (needle biochemical analysis, tree defoliation etc.) accompanied hyperspectral imagery acquisition. An analysis was conducted assessing a set of 16 vegetation indices providing complex information on foliage, biochemistry and canopy biophysics and structure. Five of them (NDVI, NDVI705, VOG1, MSR and TCARI/OSAVI) showing the best results were employed to study spatial gradients as well as temporal changes. The detected gradients are in accordance with ground truth data on representative trees. The obtained results indicate that the original significant differences between the damaged and undamaged stands have been generally levelled until 2013, although it is still possible to detect signs of the previous damages in several cases.

  13. The role of soil drainage class in carbon dioxide exchange and decomposition in boreal black spruce (Picea mariana) forest stands

    USGS Publications Warehouse

    Wickland, K.P.; Neff, J.C.; Harden, J.W.

    2010-01-01

    Black spruce (Picea mariana (Mill.) B.S.P.) forest stands range from well drained to poorly drained, typically contain large amounts of soil organic carbon (SOC), and are often underlain by permafrost. To better understand the role of soil drainage class in carbon dioxide (CO2) exchange and decomposition, we measured soil respiration and net CO2 fluxes, litter decomposition and litterfall rates, and SOC stocks above permafrost in three Alaska black spruce forest stands characterized as well drained (WD), moderately drained (MD), and poorly drained (PD). Soil respiration and net CO2 fluxes were not significantly different among sites, although the relation between soil respiration rate and temperature varied with site (Qw: WD > MD > PD). Annual estimated soil respiration, litter decomposition, and groundcover photosynthesis were greatest at PD. These results suggest that soil temperature and moisture conditions in shallow organic horizon soils at PD were more favorable for decomposition compared with the better drained sites. SOC stocks, however, increase from WD to MD to PD such that surface decomposition and C storage are diametric. Greater groundcover vegetation productivity, protection of deep SOC by permafrost and anoxic conditions, and differences in fire return interval and (or) severity at PD counteract the relatively high near-surface decomposition rates, resulting in high net C accumulation.

  14. 75 FR 68319 - Paulina Ranger District; Ochoco National Forest; Crook and Wheeler Counties, OR; Jackson...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-05

    ... other resources. Methods that would be used to reduce tree density and hazardous fuels are: non... shrub and grass communities from fire exclusion; stand density and forest fuels adjacent to arterial... forest by reducing stand density; promote the development of large trees for eventual woody...

  15. Simulating stand-level water and carbon fluxes in beetle-attacked conifer forests in the Western U.S

    NASA Astrophysics Data System (ADS)

    Peckham, S. D.; Ewers, B. E.; Mackay, D. S.; Pendall, E. G.; Frank, J. M.; Massman, W. J.

    2013-12-01

    In recent decades, forest mortality due to bark beetle infestation in conifer forests of western North America has reached epidemic levels, which may have profound effects on both present and future water and carbon cycling. The responses of evaporation, transpiration, and net photosynthesis to changing climate and disturbance are a major concern as they control the carbon balance of forests and the hydrologic cycle in a region that relies on water from montane and subalpine forest systems. Tree mortality during bark beetle infestation in this region is due to hydraulic failure resulting from fungal infection spread by the beetles. We modified the terrestrial regional ecosystem exchange simulator (TREES) model to incorporate xylem-occlusion effects on hydraulic conductance to simulate beetle attack over the period 2005-2012 in a subalpine conifer forest at the Glacier Lakes Ecosystem Experiment Site (GLEES) and over 2008-2012 at a lodgepole pine dominated site in southeast Wyoming. Model simulations with and without beetle effects were compared to eddy-covariance and sap-flux data measured at the sites. The simulations were run at a 30-minute time step and covered the pre- to post-beetle infestation period. Simulated NEE at GLEES ranged from 200 to -625 g C m-2 yr-1, annual ET ranged from 250 to 800 mm yr-1 over the seven years and standard error in predicted half-hourly NEE was <3 μmol CO2 m-2 s-1 and <2e-05 mm s-1 for ET. The stand transitioned from a C sink to C source during the beetle attack and our modified model captured this dynamic, while simulations without the beetle effect did not (i.e. continued C sink). However, simulated NEE was underestimated compared to flux data later in the infestation period (2011) by over 100 g C m-2 yr-1. ET decreased during beetle attack in both the observed and simulated data, but the modified model underestimated ET in the later phase of attack (2010-2011). These results suggest that ET and NEE in these conifer forests may

  16. Hooded-Warbler Nesting Success Adjacent to Group-Selection and Clearcut Edges in a Southeastern Bottomland Forest

    SciTech Connect

    Moorman, C.E.; Guynn, D.C., Jr.; Kilgo, J.C.

    2002-01-11

    Location and monitoring of Hooded-Warbler nests in a bottomland forest and examined the effects of edge proximity, edge type and nest-site vegetation on nesting success. Probability of parasitism by Brown-headed cowbirds was higher near clearcut edges and parasitism reduced clutch-size and numbers of fledglings per successful nest. Study was conducted in a primarily forested landscape, so cowbird abundance or negative edge effects may have been low relative to agricultural landscapes in the South.

  17. Replacing monocultures with mixed-species stands: Ecosystem service implications of two production forest alternatives in Sweden.

    PubMed

    Felton, Adam; Nilsson, Urban; Sonesson, Johan; Felton, Annika M; Roberge, Jean-Michel; Ranius, Thomas; Ahlström, Martin; Bergh, Johan; Björkman, Christer; Boberg, Johanna; Drössler, Lars; Fahlvik, Nils; Gong, Peichen; Holmström, Emma; Keskitalo, E Carina H; Klapwijk, Maartje J; Laudon, Hjalmar; Lundmark, Tomas; Niklasson, Mats; Nordin, Annika; Pettersson, Maria; Stenlid, Jan; Sténs, Anna; Wallertz, Kristina

    2016-02-01

    Whereas there is evidence that mixed-species approaches to production forestry in general can provide positive outcomes relative to monocultures, it is less clear to what extent multiple benefits can be derived from specific mixed-species alternatives. To provide such insights requires evaluations of an encompassing suite of ecosystem services, biodiversity, and forest management considerations provided by specific mixtures and monocultures within a region. Here, we conduct such an assessment in Sweden by contrasting even-aged Norway spruce (Picea abies)-dominated stands, with mixed-species stands of spruce and birch (Betula pendula or B. pubescens), or spruce and Scots pine (Pinus sylvestris). By synthesizing the available evidence, we identify positive outcomes from mixtures including increased biodiversity, water quality, esthetic and recreational values, as well as reduced stand vulnerability to pest and pathogen damage. However, some uncertainties and risks were projected to increase, highlighting the importance of conducting comprehensive interdisciplinary evaluations when assessing the pros and cons of mixtures. PMID:26744048

  18. Direct vs. Microclimate-Driven Effects of Tree Species Diversity on Litter Decomposition in Young Subtropical Forest Stands.

    PubMed

    Seidelmann, Katrin N; Scherer-Lorenzen, Michael; Niklaus, Pascal A

    2016-01-01

    Effects of tree species diversity on decomposition can operate via a multitude of mechanism, including alterations of microclimate by the forest canopy. Studying such effects in natural settings is complicated by the fact that topography also affects microclimate and thus decomposition, so that effects of diversity are more difficult to isolate. Here, we quantified decomposition rates of standard litter in young subtropical forest stands, separating effects of canopy tree species richness and topography, and quantifying their direct and micro-climate-mediated components. Our litterbag study was carried out at two experimental sites of a biodiversity-ecosystem functioning field experiment in south-east China (BEF-China). The field sites display strong topographical heterogeneity and were planted with tree communities ranging from monocultures to mixtures of 24 native subtropical tree species. Litter bags filled with senescent leaves of three native tree species were placed from Nov. 2011 to Oct. 2012 on 134 plots along the tree species diversity gradient. Topographic features were measured for all and microclimate in a subset of plots. Stand species richness, topography and microclimate explained important fractions of the variations in litter decomposition rates, with diversity and topographic effects in part mediated by microclimatic changes. Tree stands were 2-3 years old, but nevertheless tree species diversity explained more variation (54.3%) in decomposition than topography (7.7%). Tree species richness slowed litter decomposition, an effect that slightly depended on litter species identity. A large part of the variance in decomposition was explained by tree species composition, with the presence of three tree species playing a significant role. Microclimate explained 31.4% of the variance in decomposition, and was related to lower soil moisture. Within this microclimate effect, species diversity (without composition) explained 8.9% and topography 34.4% of

  19. Spatiotemporal Dynamics of Fire in Whitebark Pine Stands on two Mountains in the Lolo National Forest, Montana, USA.

    NASA Astrophysics Data System (ADS)

    Larson, E. R.; Grissino-Mayer, H. D.

    2004-12-01

    Whitebark pine (Pinus albicaulis) is a long-lived tree species that exists throughout high elevation and treeline forest communities of western North America. It is the foundation of a diminishing ecosystem that supports Clark's nutcrackers (Nucifraga columbiana), red squirrels (Tamiasciurus hudsonicus), grizzly bears (Ursus arctos), and black bears (U. americana). Several factors are directly linked to the decline of the whitebark pine ecosystem: mortality from recent and widespread mountain pine beetle (Dendroctonus ponderosae) outbreaks, infestation by the invasive white pine blister rust (Cronartium ribicola, an exotic fungal canker that weakens and eventually kills white pines), and fire suppression that may have altered the historic fire regime and enabled fire-intolerant tree species to encroach upon whitebark pine stands. The synergistic effects of these factors have led to a dramatic decline in whitebark pine communities throughout its native range, and in response land managers and conservationists have called for research to better understand the ecological dynamics of this little studied ecosystem. My research uses dendrochronology to investigate the fire history of whitebark pine stands on three mountains in the Lolo National Forest, Montana, via fire-scar and age structure analyses. I present here the results from the fire-scar analyses from Morrell Mountain where I obtained 40 cross sections from dead and down whitebark pines. Individual tree mean fire return intervals (MFRI) range from 33 to 119 years, with a stand MFRI of 49 years that includes fire scars dating to the 16th century. Fire events scarred multiple trees in AD 1754, 1796, and 1843, indicating a mixed-severity fire regime. The majority of the samples recorded a frost event in AD 1601, perhaps evidence of the AD 1600 eruption of Mt. Huaynapatina in the Peruvian Andes. My research not only provides an historical framework for land managers, but also provides an opportunity to examine long

  20. Direct vs. Microclimate-Driven Effects of Tree Species Diversity on Litter Decomposition in Young Subtropical Forest Stands

    PubMed Central

    Seidelmann, Katrin N.; Scherer-Lorenzen, Michael; Niklaus, Pascal A.

    2016-01-01

    Effects of tree species diversity on decomposition can operate via a multitude of mechanism, including alterations of microclimate by the forest canopy. Studying such effects in natural settings is complicated by the fact that topography also affects microclimate and thus decomposition, so that effects of diversity are more difficult to isolate. Here, we quantified decomposition rates of standard litter in young subtropical forest stands, separating effects of canopy tree species richness and topography, and quantifying their direct and micro-climate-mediated components. Our litterbag study was carried out at two experimental sites of a biodiversity-ecosystem functioning field experiment in south-east China (BEF-China). The field sites display strong topographical heterogeneity and were planted with tree communities ranging from monocultures to mixtures of 24 native subtropical tree species. Litter bags filled with senescent leaves of three native tree species were placed from Nov. 2011 to Oct. 2012 on 134 plots along the tree species diversity gradient. Topographic features were measured for all and microclimate in a subset of plots. Stand species richness, topography and microclimate explained important fractions of the variations in litter decomposition rates, with diversity and topographic effects in part mediated by microclimatic changes. Tree stands were 2–3 years old, but nevertheless tree species diversity explained more variation (54.3%) in decomposition than topography (7.7%). Tree species richness slowed litter decomposition, an effect that slightly depended on litter species identity. A large part of the variance in decomposition was explained by tree species composition, with the presence of three tree species playing a significant role. Microclimate explained 31.4% of the variance in decomposition, and was related to lower soil moisture. Within this microclimate effect, species diversity (without composition) explained 8.9% and topography 34.4% of

  1. Does Hawaiian native forest conserve water? Lower uptake rates at tree and stand scale by Metrosideros polymorpha relative to plantation species

    NASA Astrophysics Data System (ADS)

    Kagawa, A. K.; Sack, L.; Duarte, T. K.; James, S. A.

    2007-12-01

    Native plants are often claimed to be conservative water users that enhance groundwater recharge compared to faster-growing non-native species that tend to dominate watersheds. This argument would have implications for motivating conservation and restoration of native forest in Hawai'i. However, few studies have examined differences in native and non-native plant transpiration (water use) at species or at stand level. Our aim was determine whether species matter to stand-level water use. We measured plant transpiration in a continuous mosaic of native forest and non-native tree plantation in Honaunau, Hawaii, focusing on endemic dominant tree Metrosideros polymorpha, alien timber trees Eucalyptus saligna and Fraxinus uhdei, and dominant understory Cibotium tree ferns. We measured xylem sap flow for six individuals of each species continuously for over eight weeks, and we estimated stand water use by scaling up these measurements using stand sapwood area and tree fern leaf area values obtained through vegetation surveys. Native forest dominant Metrosideros had the lowest rates of whole-tree daily water use at 8 kg day-1 (200kg m-2sapwood day-1), less than half the daily rates for Eucalyptus or Fraxinus; Metrosideros also had the lowest maximum transpiration rates of the three tree species. At the stand level, Fraxinus-dominated stands had higher water use than Eucalyptus- and Metrosideros- dominated stands due to the species' high sap flow rates, five-fold greater sapwood allocation, and the stands' two-fold greater dominant tree density. In Metrosideros-dominated stands, high Cibotium tree fern leaf area contributed to nearly 60% of water use, indicating the fern's critical role in forest water balance. Stand water use was influenced by factors at various scales, including species composition, stem density, tree sizes, and tree species' sapwood allocation, and was affected significantly by understory contributions. These findings highlight the importance of

  2. Impulse radar measurements of snow interception - laboratory tests and field application to a forest stand in northern Sweden

    NASA Astrophysics Data System (ADS)

    Gustafsson, D.; Magnusson, J.; Granlund, N.

    2009-04-01

    Snow melt runoff is a dominating water resource in many alpine and high latitude regions. Therefore, hydrological model predictions and information on the amount of snow are important for efficient management of for instance hydropower production. Snow interception and evaporation of snow from forest canopies is known to reduce the snow cover accumulation in forest areas compared to open areas, but there is a need for better process understanding in order to improve the model predictions. The exchange of heat and water between snow cover, canopy, and atmosphere involve many processes that can be difficult to observe at the relevant scales. Particularly, the snow interception storage is difficult to observe on a forest stand level compared with snow cover development and forest evaporation. In this study, a new application of ground penetrating impulse radar (GPR) to measure the total amount, spatial distribution and phase of the interception storage in the forest canopy is presented. The propagation velocity and frequency dependent attenuation of a broadband impulse radar wave can be used to give a direct estimate of the complex effective dielectric permittivity. The real part of the effective dielectric permittivity, estimated from the propagation velocity alone, can be used to estimate either the mass of liquid water or the mass of dry snow on the canopy if a suitable mixing formula for the effective permittivity is known. However, to separate between liquid and frozen interception additional information that we intend to get from the attenuation is needed. It has been shown for snow that the liquid water content can be estimated from the imaginary component of the effective permittivity alone. Thus, the contribution from liquid water to the real component can be subtracted, and the remaining fraction depended only on the amount of frozen snow. Laboratory experiments were performed with a GPR system, measuring the propagation velocity and frequency dependent

  3. Melaleuca quinquenervia dominated forests in Florida: analyses of natural-enemy impacts on stand dynamics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Invasion by the Australian tree, Melaleuca quinquenervia (melaleuca) resulted in near-monoculture stands in vast areas of south Florida. Introduced natural enemies are hypothesized to suppress melaleuca populations and facilitate the return of native species. To test this hypothesis, we used publish...

  4. Taxation indices of forest stand as the basis for cadastral valuation of forestlands

    NASA Astrophysics Data System (ADS)

    Kovyazin, V.; Belyaev, V.; Pasko, O.; Romanchikov, A.

    2014-08-01

    Cadastral valuation of forestlands is one of the problems of the modern economy. Valuation procedures depend either on the profitability of timbering or forest areas are not differentiated according to value. The authors propose the procedure based on taxation indices of strata. The most important factors influencing the valuation are determined. The dependence that allows establishing the relative cost of a certain forest area is defined. Knowing the cadastral value of a model area, it is possible to determine the values of all other sites. The evaluation results correlate with the Faustman procedure with slight difference in the absolute value.

  5. Vegetation and disturbance history of two forest stands in northern New York using paleoecological data from small forest hollows

    SciTech Connect

    Kearsley, J.B.; Jackson, S.T.

    1995-06-01

    Pollen, macrofossils and charcoal from two small hollows (<0.05 ha) were analyzed to reconstruct the vegetational history of an outwash plain in the central Adirondack upland of New York. The basins are located 700 meters apart in contrasting modern vegetation at 461 in elevation. Dave`s Lost Hollow (DLH) is in a hemlock-dominated old-growth forest with yellow birch, red spruce and red maple, and Valhalla Hollow (VH) is surrounded by second-growth forest of white pine, balsam fir, paper birch and red maple. The record from DLH spans the entire Holocene, while VH provides data for the late Holocene. Modem pollen-vegetation data from 26 closed-canopy sites in the area provide evidence for the fine-scale sensing properties of closed- canopy pollen assemblages. We found abundant jack pine needles during the early Holocene at DLH. In contrast, data from the High Peaks, 30 km to the east, show white pine as the dominant pine species during that time period. DLH provides an early Holocene record for yellow birch in the region, whereas yellow birch was not present in the High Peaks until 6,000 yrs. B.P.

  6. Analysis of Landsat-4 Thematic Mapper data for classification of forest stands in Baldwin County, Alabama

    NASA Technical Reports Server (NTRS)

    Hill, C. L.

    1984-01-01

    A computer-implemented classification has been derived from Landsat-4 Thematic Mapper data acquired over Baldwin County, Alabama on January 15, 1983. One set of spectral signatures was developed from the data by utilizing a 3x3 pixel sliding window approach. An analysis of the classification produced from this technique identified forested areas. Additional information regarding only the forested areas. Additional information regarding only the forested areas was extracted by employing a pixel-by-pixel signature development program which derived spectral statistics only for pixels within the forested land covers. The spectral statistics from both approaches were integrated and the data classified. This classification was evaluated by comparing the spectral classes produced from the data against corresponding ground verification polygons. This iterative data analysis technique resulted in an overall classification accuracy of 88.4 percent correct for slash pine, young pine, loblolly pine, natural pine, and mixed hardwood-pine. An accuracy assessment matrix has been produced for the classification.

  7. FIELD STUDIES TO EVALUATE STAND-SCALE EFFECTS OF FOREST MANAGEMENT ON ECOSYSTEM CARBON STORAGE

    EPA Science Inventory

    This research plan provides new knowledge on the range of possibilities--available by managing forest differently--to store more carbon (C) to meet the climate-change action plant (Clinton and Gore 1993) target of returning emission of greenhouse gases in the United States to 199...

  8. Fate of Herbicides and Their Degradation Products Entering a Forested Riparian Buffer Following Herbicides Application to an Adjacent Corn Field

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fate of two herbicides, atrazine and metolachlor, were followed as they entered and moved through a forested riparian wetland located in the mid-Atlantic coastal plain of Maryland. The herbicides were applied as pre-emergent treatments to a 20-ha corn field directly upgradient of the riparian w...

  9. [Dynamics of nitrogen and sulfur wet deposition in typical forest stand at different spatial levels in Simian Mountain, mid-subtropical region].

    PubMed

    Sun, Tao; Ma, Ming; Wang, Ding-yong; Huang, Li-xin

    2014-12-01

    In order to investigate the dynamics of nitrogen and sulfur wet deposition in subtropical forest ecosystem, one typical forest stand, evergreen broad-leaved forest, at Simian Mountain located in Chongqing was selected in this research. Based on field monitoring, effects of precipitation, throughfall, litterfall, and groundwater runoff of the typical forest stand on the quality of water of Simian Mountain were investigated from September 2012 to August 2013. Results showed that the rainfall of Simian Mountain was apparently acidic, with average pH of 4.89 and maximum pH of 5.14. The soil, canopies and trunks could increase pH of precipitation, with soils having the maximum increment, followed by the forest canopy. Forest canopy had the function of adsorption and purification of NO3-, NO2- and SO4(2-), and the average entrapment rate was 56.68%, 45.84% and 35.51%, respectively. Moreover, the degradation of litter was probably the main reason for the increase of ion concentrations in the surface litter water. Forest soils could absorb and neutralize NO3-, SO2- and NH4+, and release NO2-. The evergreen broad-leaf forest of mid-subtropical region had the function of interception on NO3-, NO2-, NH4+ and SO4(2-), and the total entrapment rate was 92.86%, 57.86%, 87.24% and 87.25%, respectively, and it had a certain buffering function for the acid rain. PMID:25826915

  10. Simulation of boreal forest carbon dynamics after stand-replacing fire disturbance: validation and model evaluation of a global vegetation model

    NASA Astrophysics Data System (ADS)

    Yue, C.; Cadule, P.; Ciais, P.; Viovy, N.; Bellassen, V.; Luyssaert, S.

    2012-04-01

    This study simulates boreal forest carbon dynamics after stand-replacing fire disturbance, using a process-based vegetation model called ORCHIDEE. The aim is to calibrate the forest stand structure, and carbon flux and carbon pools after fire disturbance. To achieve this aim, we used a new "forestry" module in ORCHIDEE which can explicitly represent forest structure and the process of self-thinning. Observations in three post-fire forest chronosequences in North America (Detla Junction in Alaska, Thompson in Manitoba, Canada and Albert in Saskathewan, Canada) were used as validation data. The validation variables include: stand density and mean diameter at breast height (DBH), annual GPP, NPP, NEP and ecosystem respiration, total biomass carbon (or above-ground biomass carbon), forest floor carbon, coarse woody debris (CWD) carbon, and mineral soil carbon. We chose a fire return interval of 160 years in the simulation. The model results generally compare well with the observation. Following a stand-replacing fire, (1) GPP and NPP increase steadily during forest regrowth until 30-40 years when the increase either stops or slows down. Slight decrease in GPP in the later growth stage occurs and NPP decreases more significantly. The heterotrophic respiration undergoes a surge immediately after burning and then remains relatively stable during the forest regrowth. Consequently, the net ecosystem production remains negative (the ecosystem being a CO2 source for the atmosphere) for 20-30 years after fire, after which the forest begins to function as a CO2 sink. This CO2 sink peaks in the intermediate stage, and it is followed by a decrease again in later stages before the next disturbance event. Over the whole fire return interval, the net carbon exchange is mainly controlled by forest NPP. (2) The biomass carbon stock increases steadily after disturbance and then more slowly in later succession stages. Forest floor carbon (i.e. aboveground litter or soil organic carbon

  11. Estimating Wood Volume for Pinus Brutia Trees in Forest Stands from QUICKBIRD-2 Imagery

    NASA Astrophysics Data System (ADS)

    Patias, Petros; Stournara, Panagiota

    2016-06-01

    Knowledge of forest parameters, such as wood volume, is required for a sustainable forest management. Collecting such information in the field is laborious and even not feasible in inaccessible areas. In this study, tree wood volume is estimated utilizing remote sensing techniques, which can facilitate the extraction of relevant information. The study area is the University Forest of Taxiarchis, which is located in central Chalkidiki, Northern Greece and covers an area of 58km2. The tree species under study is the conifer evergreen species P. brutia (Calabrian pine). Three plot surfaces of 10m radius were used. VHR Quickbird-2 images are used in combination with an allometric relationship connecting the Tree Crown with the Diameter at breast height (Dbh), and a volume table developed for Greece. The overall methodology is based on individual tree crown delineation, based on (a) the marker-controlled watershed segmentation approach and (b) the GEographic Object-Based Image Analysis approach. The aim of the first approach is to extract separate segments each of them including a single tree and eventual lower vegetation, shadows, etc. The aim of the second approach is to detect and remove the "noisy" background. In the application of the first approach, the Blue, Green, Red, Infrared and PCA-1 bands are tested separately. In the application of the second approach, NDVI and image brightness thresholds are utilized. The achieved results are evaluated against field plot data. Their observed difference are between -5% to +10%.

  12. Use of Airborne LiDAR To Estimate Forest Stand Characteristics

    NASA Astrophysics Data System (ADS)

    Li, Qi; Zhou, Wei; Li, Chang

    2014-03-01

    Small-Footprint Airborne LiDAR(light detection and ranging) remote sensing is a breakthrough technology for deriving forest canopy structural characteristics. Because the technique is relatively new as applied to canopy measurement in China, there is a tremendous need for experiments that integrate field work, LiDAR remote sensing and subsequent analyses for retrieving the full complement of structural measures critical for forestry applications. Data storage capacity and high processing speed available today have made it possible to digitally sample and store the entire reflected waveform, instead of only extracting the discrete coordinates which form the so-called point clouds. Return waveforms can give more detailed insights into the vertical structure of surface objects, surface slope, roughness and reflectivity than the conventional echoes. In this paper, an improved Expectation Maximum (EM) algorithm is adopted to decompose raw waveform data. Derived forest biophysical parameters, such as vegetation height, subcanopy topography, crown volume, ground reflectivity, vegetation reflectivity and canopy closure, are able to describe the horizontal and vertical forest canopy structure.

  13. Influence of nutrient availability, stand age, and canopy structure on isoprene flux in a Eucalyptus saligna experimental forest

    NASA Astrophysics Data System (ADS)

    Funk, Jennifer L.; Giardina, Christian P.; Knohl, Alexander; Lerdau, Manuel T.

    2006-06-01

    Eucalyptus plantations occupy approximately 10 million ha of land in the tropics and, increasingly, afforestation and reforestation projects are relying on this genus to provide rapid occupation of degraded sites, large quantities of high-quality wood products, and high rates of carbon sequestration. Members of the genus Eucalyptus are also very high emitters of isoprene, the dominant volatile organic compound emitted by trees in tropical ecosystems, which significantly influences the oxidative capacity of the atmosphere. While fertilization growth response of these trees has been intensively studied, little is known about how fertilization and tree age alter isoprene production from plantations of these trees. Here we examined the effects of fertilization and tree age on leaf-level isoprene flux from 2- and 6-year-old trees in a Eucalyptus saligna experimental forest in Hawaii. Leaf-level emission at a given canopy height did not differ between fertilized and unfertilized 6-year-old trees likely because leaf nitrogen content did not vary with fertilization. Across treatments, however, the standardized emission rate of isoprene (emission at a standard light and temperature) followed patterns of leaf N content and declined with canopy depth. Although leaf nitrogen content was similar between 2-year and 6-year fertilized trees, leaf-level emission rates declined with stand age. Surprisingly, despite differences in stand leaf area and leaf area distribution, modeled canopy-level isoprene flux was similar across stands varying in fertilization and tree age. Model results suggest that leaf area index was high enough in all treatments to absorb most of the light penetrating the canopy, leading to similar canopy flux rates despite the very different sized canopies.

  14. Sensitivity of ERS-1 and JERS-1 radar data to biomass and stand structure in Alaskan boreal forest

    SciTech Connect

    Harrell, P.A.; Christensen, N.L. Jr.; Bourgeau-Chavez, L.L.; Kasischke, E.S.; French, N.H.F.

    1995-12-01

    As the boreal system is such an important component of the global carbon budget, it is important that the system and the potential changes be understood, whether from anthropogenic disturbances or global climate change. Thirty-two boreal forest sites were identified and sampled in the central region of Alaska to evaluate the sensitivity of the C-band ERS-1 and the L-band JERS-1 radar platforms to site biophysical properties. The sites selected represent black spruce (Picea mariana) and white spruce (Picea glauca) stands in a post-fire chronosequence. Black spruce biomass ranged from less than 1 kg/m{sup 2} to 5.6 kg/m{sup 2} and white spruce from 8.8 to 21.5 kg/m{sup 2}. Results indicate both ERS-1 and JERS-1 backscatter is responsive to biomass, density, and height, though other factors, principally surface moisture conditions, are often a stronger influence. Sensitivity to forest biomass and structure appears greatest when surface moisture conditions are minimized as a factor. Biomass correlations with the radar backscatter were strongest in the late winter imagery when all sites had a snow cover, and late summer when the surface is most dry. ERS-1 data may be more sensitive to surface moisture conditions than the JERS-1 data due to the shorter wavelength of the C-band sensor, though this is inconclusive because of limited JERS-1 L-band data for comparison.

  15. Sources of uncertainty in stand-level predictions of forest response to tropospheric ozone

    SciTech Connect

    Smith, J.E.; Woodbury, P.B.; Laurence, J.A.

    1995-09-01

    We present a simple model to analyze uncertainty in predicted effects of tropospheric ozone on loblolly pine stands in southeastern USA. Assessment of pollution stress on an ecosystem requires the intergration of many, possibly disparate, datasets to produce a quality-estimate of the information provided for resource management and policy formulation. We are developing procedures to identify and quantify sources of uncertainty in a simple, flexible modeling context. We incorporated published data from experimental, observational, and modeling research into the uncertainty analysis. Major sources of uncertainty arise in combining results from diverse studies and from scaling what are usually seedling data (from exposure chambers) to growth of mature trees. Our model of loblolly stand productivity explicitly states relationships among sources of uncertainty and uses Monte Carlo simulations to estimate relative influences. This approach allows researchers or analysts to examine how uncertain model predictions are affected by (1) assumptions about how system components are related and (2) acquisition of additional information through further research.

  16. Identifying Standing Dead Trees in Forest Areas Based on 3d Single Tree Detection from Full Waveform LIDAR Data

    NASA Astrophysics Data System (ADS)

    Yao, W.; Krzystek, P.; Heurich, M.

    2012-07-01

    In forest ecology, a snag refers to a standing, partly or completely dead tree, often missing a top or most of the smaller branches. The accurate estimation of live and dead biomass in forested ecosystems is important for studies of carbon dynamics, biodiversity, and forest management. Therefore, an understanding of its availability and spatial distribution is required. So far, LiDAR remote sensing has been successfully used to assess live trees and their biomass, but studies focusing on dead trees are rare. The paper develops a methodology for retrieving individual dead trees in a mixed mountain forest using features that are derived from small-footprint airborne full waveform LIDAR data. First, 3D coordinates of the laser beam reflections, the pulse intensity and width are extracted by waveform decomposition. Secondly, 3D single trees are detected by an integrated approach, which delineates both dominate tree crowns and understory small trees in the canopy height model (CHM) using the watershed algorithm followed by applying normalized cuts segmentation to merged watershed areas. Thus, single trees can be obtained as 3D point segments associated with waveform-specific features per point. Furthermore, the tree segments are delivered to feature definition process to derive geometric and reflectional features at single tree level, e.g. volume and maximal diameter of crown, mean intensity, gap fraction, etc. Finally, the spanned feature space for the tree segments is forwarded to a binary classifier using support vector machine (SVM) in order to discriminate dead trees from the living ones. The methodology is applied to datasets that have been captured with the Riegl LMSQ560 laser scanner at a point density of 25 points/m2 in the Bavarian Forest National Park, Germany, respectively under leaf-on and leaf-off conditions for Norway spruces, European beeches and Sycamore maples. The classification experiments lead in the best case to an overall accuracy of 73% in a leaf

  17. Compensating effect of sap velocity for stand density leads to uniform hillslope-scale forest transpiration across a steep valley cross-section

    NASA Astrophysics Data System (ADS)

    Renner, Maik; Hassler, Sibylle; Blume, Theresa; Weiler, Markus; Hildebrandt, Anke; Guderle, Marcus; Schymanski, Stan; Kleidon, Axel

    2016-04-01

    Roberts (1983) found that forest transpiration is relatively uniform across different climatic conditions and suggested that forest transpiration is a conservative process compensating for environmental heterogeneity. Here we test this hypothesis at a steep valley cross-section composed of European Beech in the Attert basin in Luxemburg. We use sapflow, soil moisture, biometric and meteorological data from 6 sites along a transect to estimate site scale transpiration rates. Despite opposing hillslope orientation, different slope angles and forest stand structures, we estimated relatively similar transpiration responses to atmospheric demand and seasonal transpiration totals. This similarity is related to a negative correlation between sap velocity and site-average sapwood area. At the south facing sites with an old, even-aged stand structure and closed canopy layer, we observe significantly lower sap velocities but similar stand-average transpiration rates compared to the north-facing sites with open canopy structure, tall dominant trees and dense understorey. This suggests that plant hydraulic co-ordination allows for flexible responses to environmental conditions leading to similar transpiration rates close to the water and energy limits despite the apparent heterogeneity in exposition, stand density and soil moisture. References Roberts, J. (1983). Forest transpiration: A conservative hydrological process? Journal of Hydrology 66, 133-141.

  18. Forest fragments as barriers to fruit fly dispersal: Anastrepha (Diptera: Tephritidae) populations in orchards and adjacent forest fragments in Puerto Rico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    McPhail-type traps baited with ammonium acetate and putrescine were used to monitor populations of Anastrepha obliqua and A. suspensa at four sites in Guánica, Puerto Rico; one forest fragment in Ponce, Puerto Rico; in a commercial mango orchard in Guayanilla, PR; and an experimental carambola orcha...

  19. 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.

  20. Changes in carbon pool and stand structure of a native subtropical mangrove forest after inter-planting with exotic species Sonneratia apetala.

    PubMed

    Lu, Weizhi; Yang, Shengchang; Chen, Luzhen; Wang, Wenqing; Du, Xiaona; Wang, Canmou; Ma, Yan; Lin, Guangxuan; Lin, Guanghui

    2014-01-01

    In this study, we compared stand structure, biomass and soil carbon pools, and litterfall production between a mixed mangrove forest consisting of Aegiceras corniculatum inter-planted with the exotic Sonneratia apetala and a native monospecific forest dominated by A. corniculatum in the intertidal area of Zhanjiang, Guangdong Province, southeast China. The goal of this study was to test the hypothesis that inter-planting fast growing exotic mangrove S. apetala into subtropical native mangrove forests will significantly increase C sequestration. Although the tree heights and basal diameters of S. apetala were significantly higher than those of A. corniculatum, the density of the 12-year-old S. apetala trees in the mixed forest was much smaller than that of A. corniculatum in the monospecific forest. In contrast to several previous studies on S. apetala forests planted directly on mangrove-free mudflats, the mixed mangrove forest showed no significant difference in either standing biomass or soil carbon pools from the native monospecific mangrove forest (p = 0.294 and 0.073, respectively) twelve years after inter-planting with S. apetala. Moreover, carbon cycling was likely speeded up after inter-planting S. apetala due to higher litterfall input and lower C/N ratio. Thus, inter-planting fast-growing S. apetala into native mangrove forest is not an effective way to increase carbon sequestration in this subtropical mangrove forest. Given that exotic plant species may exert negative impact on native mangrove species and related epifauna, this fast-growing mangrove species is not suitable for mangrove plantation projects aiming mainly at enhancing carbon sequestration. PMID:24618793

  1. Changes in Carbon Pool and Stand Structure of a Native Subtropical Mangrove Forest after Inter-Planting with Exotic Species Sonneratia apetala

    PubMed Central

    Lu, Weizhi; Yang, Shengchang; Chen, Luzhen; Wang, Wenqing; Du, Xiaona; Wang, Canmou; Ma, Yan; Lin, Guangxuan; Lin, Guanghui

    2014-01-01

    In this study, we compared stand structure, biomass and soil carbon pools, and litterfall production between a mixed mangrove forest consisting of Aegiceras corniculatum inter-planted with the exotic Sonneratia apetala and a native monospecific forest dominated by A. corniculatum in the intertidal area of Zhanjiang, Guangdong Province, southeast China. The goal of this study was to test the hypothesis that inter-planting fast growing exotic mangrove S. apetala into subtropical native mangrove forests will significantly increase C sequestration. Although the tree heights and basal diameters of S. apetala were significantly higher than those of A. corniculatum, the density of the 12-year-old S. apetala trees in the mixed forest was much smaller than that of A. corniculatum in the monospecific forest. In contrast to several previous studies on S. apetala forests planted directly on mangrove-free mudflats, the mixed mangrove forest showed no significant difference in either standing biomass or soil carbon pools from the native monospecific mangrove forest (p = 0.294 and 0.073, respectively) twelve years after inter-planting with S. apetala. Moreover, carbon cycling was likely speeded up after inter-planting S. apetala due to higher litterfall input and lower C/N ratio. Thus, inter-planting fast-growing S. apetala into native mangrove forest is not an effective way to increase carbon sequestration in this subtropical mangrove forest. Given that exotic plant species may exert negative impact on native mangrove species and related epifauna, this fast-growing mangrove species is not suitable for mangrove plantation projects aiming mainly at enhancing carbon sequestration. PMID:24618793

  2. Revisiting a universal airborne light detection and ranging approach for tropical forest carbon mapping: scaling-up from tree to stand to landscape.

    PubMed

    Vincent, Grégoire; Sabatier, Daniel; Rutishauser, Ervan

    2014-06-01

    Airborne laser scanning provides continuous coverage mapping of forest canopy height and thereby is a powerful tool to scale-up above-ground biomass (AGB) estimates from stand to landscape. A critical first step is the selection of the plot variables which can be related to light detection and ranging (LiDAR) statistics. A universal approach was previously proposed which combines local and regional estimates of basal area (BA) and wood density with LiDAR-derived canopy height to map carbon at a regional scale (Asner et al. in Oecologia 168:1147-1160, 2012). Here we explore the contribution of stem diameter distribution, specific wood density and height-diameter (H-D) allometry to forest stand AGB and propose an alternative model. By applying the new model to a large tropical forest data set we show that an appropriate choice of input variables is essential to minimize prediction error of stand AGB which will propagate at larger scale. Stem number (N) and average stem cross-sectional area should be used instead of BA when scaling from tree to plot. Stand quadratic mean diameter above the census threshold diameter size should be preferred over stand mean diameter as it reduces the prediction error of stand AGB by a factor of ten. Wood density should be weighted by stem volume per species instead of BA. LiDAR-derived statistics should prove useful for estimating local H-D allometries as well as mapping N and the mean quadratic diameter above 10 cm at the landscape level. Prior stratification into forest types is likely to improve both estimation procedures significantly and is considered the foremost current challenge. PMID:24615493

  3. Analysis of multiple incidence angle SIR-B data for determining forest stand characteristics

    NASA Technical Reports Server (NTRS)

    Hoffer, R. M.; Lozano-Garcia, D. F.; Gillespie, D. D.; Mueller, P. W.; Ruzek, M. J.

    1986-01-01

    For the first time in the U.S. space program, digital synthetic aperture radar (SR) data were obtained from different incidence angles during Space Shuttle Mission 41-G. Shuttle Imaging Radar-B (SIR-B) data were obtained at incidence angles of 58 deg., 45 deg., and 28 deg., on October 9, 10, and 11, 1984, respectively, for a predominantly forested study area in northern Florida. Cloud-free LANDSAT Thematic Mapper (T.M.) data were obtained over the same area on October 12. The SIR-B data were processed and then digitally registered to the LANDSAT T.M. data by scientists at the Jet Propulsion Laboratory. This is the only known digitally registered SIR-B and T.M. data set for which the data were obtained nearly simultaneously. The data analysis of this information is discussed.

  4. Ground beetle (Coleoptera, Carabidae) assemblages inhabiting Scots pine stands of Puszcza Piska Forest: six-year responses to a tornado impact

    PubMed Central

    Skłodowski, Jarosław; Garbalińska, Paulina

    2011-01-01

    Abstract Ground beetle assemblages were studied during 2003-08 in the Pisz Forest by comparing stands disturbed by a tornado to undisturbed control stands. The following exploratory questions were put forward. (1) How do the carabid assemblages change during six years following the tornado impact? (2) Does the carabid assemblage recovery begin during the six first post-tornado years? To assess the state of carabid assemblages we used two indices: the MIB (Mean Individual Biomass) and the SPC (Sum of Progressive Characteristics). Carabid assemblages in the disturbed and in the control stands, as expressed by these two indices, were compared using the length of a regression distance (sample distance in a MIB:SPC coordinate system). A cluster analysis revealed that the assemblages of the disturbed and the control stands were different. The tornado-impacted stands produced lower carabid catch rates, but species richness was significantly higher there than in the control stands. They hosted lower proportions of individuals of European species, of large zoophages, and of forest and brachypterous species, than the control stands. The observed reduction in SPC and MIB, and an increase in the regression distances may indicate that the carabid assemblages had not started to recover from the tornado-caused disturbance. Carabid assemblages apparently responded to the tornado in two steps. Firstly, the first three years were characterized by moderate decreases of index values. Secondly, from the fourth to the sixth year after the tornado, many observed changes became magnified. We did not observe clear signals of the recovery of forest carabid assemblages during the six follow-up years. PMID:21738422

  5. Ground beetle (Coleoptera, Carabidae) assemblages inhabiting Scots pine stands of Puszcza Piska Forest: six-year responses to a tornado impact.

    PubMed

    Skłodowski, Jarosław; Garbalińska, Paulina

    2011-01-01

    Ground beetle assemblages were studied during 2003-08 in the Pisz Forest by comparing stands disturbed by a tornado to undisturbed control stands. The following exploratory questions were put forward. (1) How do the carabid assemblages change during six years following the tornado impact? (2) Does the carabid assemblage recovery begin during the six first post-tornado years? To assess the state of carabid assemblages we used two indices: the MIB (Mean Individual Biomass) and the SPC (Sum of Progressive Characteristics). Carabid assemblages in the disturbed and in the control stands, as expressed by these two indices, were compared using the length of a regression distance (sample distance in a MIB:SPC coordinate system). A cluster analysis revealed that the assemblages of the disturbed and the control stands were different. The tornado-impacted stands produced lower carabid catch rates, but species richness was significantly higher there than in the control stands. They hosted lower proportions of individuals of European species, of large zoophages, and of forest and brachypterous species, than the control stands. The observed reduction in SPC and MIB, and an increase in the regression distances may indicate that the carabid assemblages had not started to recover from the tornado-caused disturbance. Carabid assemblages apparently responded to the tornado in two steps. Firstly, the first three years were characterized by moderate decreases of index values. Secondly, from the fourth to the sixth year after the tornado, many observed changes became magnified. We did not observe clear signals of the recovery of forest carabid assemblages during the six follow-up years. PMID:21738422

  6. Physiological studies in young Eucalyptus stands in southern India and their use in estimating forest transpiration

    SciTech Connect

    Roberts, J.M.; Rosier, P.T.W.; Murthy, K.V.

    1992-12-31

    Stomatal conductance, leaf water potential and leaf area index were measured in adjacent plantations of Eucalyptus camaldulensis and Eucalyptus tereticornis at Puradal, near Shimoga, Karnataka, southern India. The data were collected in a range of climatic conditions during a two year period immediately following plantation establishment. Physiological differences between the two species were small and confined largely to leaf area index. Stomatal conductance was highest in the post-monsoon period and declined to minimum values immediately prior to the onset of the monsoon, with the lowest conductances observed after the plantations had been established for more than one year. Stomatal conductance, leaf area index and above-canopy meteorological data were combined in a multi-layer transpiration model and used to calculate hourly values of transpiration from the two species. Rates of transpiration up to 6 mm d{sup {minus}1} were estimated for the post-monsoon period but fell to below 1 mm d{sup {minus}1} prior to the monsoon.

  7. BOREAS TE-9 In Situ Diurnal Gas Exchange of NAS Boreal Forest Stands

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Margolis, Hank; Coyea, Marie; Dang, Qinglai

    2000-01-01

    The BOREAS TE-9 team collected several data sets related to chemical and photosynthetic properties of leaves in boreal forest tree species. The purpose of the BOREAS TE-09 study was threefold: 1) to provide in situ gas exchange data that will be used to validate models of photosynthetic responses to light, temperature, and carbon dioxide (CO2); 2) to compare the photosynthetic responses of different tree crown levels (upper and lower); and 3) to characterize the diurnal water potential curves for these sites to get an indication of the extent to which soil moisture supply to leaves might be limiting photosynthesis. The gas exchange data of the BOREAS NSA were collected to characterize diurnal gas exchange and water potential of two canopy levels of five boreal canopy cover types: young jack pine, old jack pine, old aspen, lowland old black spruce, and upland black spruce. These data were collected between 27-May-1994 and 17-Sep-1994. The data are provided in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  8. Using LiDAR to Estimate Total Aboveground Biomass of Redwood Stands in the Jackson Demonstration State Forest, Mendocino, California

    NASA Astrophysics Data System (ADS)

    Rao, M.; Vuong, H.

    2013-12-01

    The overall objective of this study is to develop a method for estimating total aboveground biomass of redwood stands in Jackson Demonstration State Forest, Mendocino, California using airborne LiDAR data. LiDAR data owing to its vertical and horizontal accuracy are increasingly being used to characterize landscape features including ground surface elevation and canopy height. These LiDAR-derived metrics involving structural signatures at higher precision and accuracy can help better understand ecological processes at various spatial scales. Our study is focused on two major species of the forest: redwood (Sequoia semperirens [D.Don] Engl.) and Douglas-fir (Pseudotsuga mensiezii [Mirb.] Franco). Specifically, the objectives included linear regression models fitting tree diameter at breast height (dbh) to LiDAR derived height for each species. From 23 random points on the study area, field measurement (dbh and tree coordinate) were collected for more than 500 trees of Redwood and Douglas-fir over 0.2 ha- plots. The USFS-FUSION application software along with its LiDAR Data Viewer (LDV) were used to to extract Canopy Height Model (CHM) from which tree heights would be derived. Based on the LiDAR derived height and ground based dbh, a linear regression model was developed to predict dbh. The predicted dbh was used to estimate the biomass at the single tree level using Jenkin's formula (Jenkin et al 2003). The linear regression models were able to explain 65% of the variability associated with Redwood's dbh and 80% of that associated with Douglas-fir's dbh.

  9. Survey of Lava Tubes in the Former Puna Forest Reserve and on Adjacent State of Hawaii Lands

    SciTech Connect

    McEldowney, H.; Stone, F.D.

    1991-10-01

    This study was initiated after members of the Puna community brought to the attention of the Historic Preservation Office that major lava tube systems extended from the Pahoa area into at least portions of the former Puna Forest Reserve. They were concerned that planned geothermal exploration and development could damage these lava tubes which they said contained extensive evidence of past Hawaiian use including fortifications, shrines, platforms and burials. Geothermal development is currently being planned by Campbell Estate and True Geothermal Energy Company in the southern portion of the former Reserve which has been designated by the State of Hawaii as one of the three Geothermal Sub-Zones in Puna. To demonstrate these claims, two staff members of the Historic Sites Section were shown examples in a lava tube makai of the Campbell Estate boundary. After reviewing the archaeological and historical reports commissioned for geothermal exploration, it was agreed that if these lava tubes did extend inland and continued to contain archaeological sites or burials then the potential of significant sub-surface sites had not been adequately addressed in the Historic Sites Section review process. Most reports acknowledged the possibility of lava tubes in the area and that they could contain burials, but no tube systems were ever identified or explored during any of the field surveys. These surveys primarily assessed the presence or absence of cultural properties that occur on the surface or as deposits within the soil layer. With the assistance of the Division of Water Resource Management (DWRM), the Historic Sites Section agreed to conduct this survey because those community members who came forward requested that this information be handled by a neutral party. They asked that documentation occur in such a manner that it could be kept as confidential as possible while still providing enough information to protect any sites from damage. The survey had three major aims

  10. Dynamics of Litter Decomposition, Microbiota Populations, and Nutrient Movement Following Nitrogen and Phosphorus Additions to a Deciduous Forest Stand

    SciTech Connect

    Kelly, J.M.

    2002-10-29

    The objective of this study was quantification of the dynamics of litter decomposition, microbiota populations, and nutrient movement in response to nitrogen and phosphorus additions to a deciduous forest stand. Nitrogen (urea) was applied at rates of 0, 550, and 1100 kg/ha in combination with phosphorus (concentrated superphosphate) at rates of 0, 275, and 550 kg/ha. Total loss of organic material from white oak, red maple, and black gum litter bags over a 16-month period was 34, 35, and 45%, respectively. Phosphorus treatment retarded weight loss from litter bags of all species. Weight loss for the 0-, 275-, and 55-kg/ha levels of phosphorus averaged 23, 20, and 19% for white oak; 26, 25, and 25% for red maple; 29, 27 and 26% for black gum. Weight losses were increased by a small amount (1 to 2%) or not at all by nitrogen treatment. The NP interfaction weight loss means were intermediate to the main treatment means. The increase in decomposition associated with nitrogen was offset by the decrease associated with phosphorus. Litter and soil bacterial populations were significantly increased by nitrogen additions, while litter and soil fungi did not respond to nitrogen. Soil fungal populations were increased by phosphorus addition, while litter bacterial populations were reduced. Litter fungi and soil bacteria did not respond to phosphorus. Combined additions of nitrogen and phosphorus increased bacterial populations, though not as much as nitrogen alone. There was a good correlation (r = 0.70) between bacterial population and litter weight loss.

  11. Influence of Human Pressure on Forest Resources and Productivity at Stand and Tree Scales: The Case Study of Yunnan Pine in SW China

    PubMed Central

    HINCKLEY, Thomas M.; CHI, Phillip; HAGMANN, Keala; HARRELL, Stevan; SCHMIDT, Amanda Henck; URGENSON, Lauren; ZENG, Zong-yong

    2015-01-01

    This paper examines human impact on stands and individual trees of Pinus yunnanensis growing near the small mountain villages of Pianshui and Yangjuan in southwestern Sichuan Province, China. In an effort to assess whether use of these forests was sustainable, we examined the effects of human use in two ways. First, we directly measured the effect of cutting branches, for fuel and fodder, on tree growth. We hypothesized that branch cutting would negatively impact tree growth. We established 12 plots on four hills and compared 14 pairs of trees, one tree in each pair with an apparently full crown and the other with a considerable portion of the crown removed. Second, we assessed stand and tree properties over a 500 m elevation gradient above the villages where we hypothesized that as elevation increases, stand and tree properties should show fewer human impacts. Although extensive branch cutting reduced the live crown, tree height and diameter, compensatory processes likely enabled trees to recover and to add basal area increments (BAIs) similar to those added by trees with full crowns. Trees and stands close to villages showed less growth and lower basal areas, respectively, than stands and trees at intermediate or distant elevations from villages. Areas relatively close to the villages showed considerable effects of human-related disturbances such as branch cutting, grazing, tree and shrub removal, losses of litter, and human and animal trails. Such areas had increased soil erosion and often loss of the ‘A’ horizon. Stands close to villages had younger trees, lower stand basal areas, smaller basal area increments, and more stumps. Our results suggest an increasingly vulnerable interface between occupants of these two villages and their surrounding forests. PMID:26478727

  12. Stand and landscape level effects of a major outbreak of spruce beetles on forest vegetation in the Copper River Basin, Alaska

    USGS Publications Warehouse

    Allen, J.L.; Wesser, S.; Markon, C.J.; Winterberger, K.C.

    2006-01-01

    From 1989 to 2003, a widespread outbreak of spruce beetles (Dendroctonus rufipennis) in the Copper River Basin, Alaska, infested over 275,000 ha of forests in the region. During 1997 and 1998, we measured forest vegetation structure and composition on one hundred and thirty-six 20-m ?? 20-m plots to assess both the immediate stand and landscape level effects of the spruce beetle infestation. A photo-interpreted vegetation and infestation map was produced using color-infrared aerial photography at a scale of 1:40,000. We used linear regression to quantify the effects of the outbreak on forest structure and composition. White spruce (Picea glauca) canopy cover and basal area of medium-to-large trees [???15 cm diameter-at-breast height (1.3 m, dbh)] were reduced linearly as the number of trees attacked by spruce beetles increased. Black spruce (Picea mariana) and small diameter white spruce (<15 cm dbh) were infrequently attacked and killed by spruce beetles. This selective attack of mature white spruce reduced structural complexity of stands to earlier stages of succession and caused mixed tree species stands to lose their white spruce and become more homogeneous in overstory composition. Using the resulting regressions, we developed a transition matrix to describe changes in vegetation types under varying levels of spruce beetle infestations, and applied the model to the vegetation map. Prior to the outbreak, our study area was composed primarily of stands of mixed white and black spruce (29% of area) and pure white spruce (25%). However, the selective attack on white spruce caused many of these stands to transition to black spruce dominated stands (73% increase in area) or shrublands (26% increase in area). The post-infestation landscape was thereby composed of more even distributions of shrubland and white, black, and mixed spruce communities (17-22% of study area). Changes in the cover and composition of understory vegetation were less evident in this study

  13. A stand-alone tree demography and landscape structure module for Earth system models: integration with inventory data from temperate and boreal forests

    NASA Astrophysics Data System (ADS)

    Haverd, V.; Smith, B.; Nieradzik, L. P.; Briggs, P. R.

    2014-08-01

    Poorly constrained rates of biomass turnover are a key limitation of Earth system models (ESMs). In light of this, we recently proposed a new approach encoded in a model called Populations-Order-Physiology (POP), for the simulation of woody ecosystem stand dynamics, demography and disturbance-mediated heterogeneity. POP is suitable for continental to global applications and designed for coupling to the terrestrial ecosystem component of any ESM. POP bridges the gap between first-generation dynamic vegetation models (DVMs) with simple large-area parameterisations of woody biomass (typically used in current ESMs) and complex second-generation DVMs that explicitly simulate demographic processes and landscape heterogeneity of forests. The key simplification in the POP approach, compared with second-generation DVMs, is to compute physiological processes such as assimilation at grid-scale (with CABLE (Community Atmosphere Biosphere Land Exchange) or a similar land surface model), but to partition the grid-scale biomass increment among age classes defined at sub-grid-scale, each subject to its own dynamics. POP was successfully demonstrated along a savanna transect in northern Australia, replicating the effects of strong rainfall and fire disturbance gradients on observed stand productivity and structure. Here, we extend the application of POP to wide-ranging temporal and boreal forests, employing paired observations of stem biomass and density from forest inventory data to calibrate model parameters governing stand demography and biomass evolution. The calibrated POP model is then coupled to the CABLE land surface model, and the combined model (CABLE-POP) is evaluated against leaf-stem allometry observations from forest stands ranging in age from 3 to 200 year. Results indicate that simulated biomass pools conform well with observed allometry. We conclude that POP represents an ecologically plausible and efficient alternative to large-area parameterisations of woody

  14. Factors influencing spatial pattern in tropical forest clearance and stand age: Implications for carbon storage and species diversity

    NASA Astrophysics Data System (ADS)

    Helmer, E. H.; Brandeis, Thomas J.; Lugo, Ariel E.; Kennaway, Todd

    2008-06-01

    Little is known about the tropical forests that undergo clearing as urban/built-up and other developed lands spread. This study uses remote sensing-based maps of Puerto Rico, multinomial logit models and forest inventory data to explain patterns of forest age and the age of forests cleared for land development and assess their implications for forest carbon storage and tree species richness. Accessibility, arability and spatial contagion emerge strongly as overriding spatial controls on tropical forest age, determining (1) the pattern of agricultural abandonment that permits forest regrowth, and (2) where humans leave old-growth forest remnants. Covariation between the factors patterning forest age and land development explains why most forest cleared for land development is younger. Forests are increasingly younger in more accessible and fertile areas where agriculture has lasted longer and land development is most common. All else equal, more species-rich older forest on less arable lands are somewhat less likely to undergo development, but they are still vulnerable to clearing for land development if close to urban centers and unprotected. Accounting for forest age leads to a 19% lower estimate of forest biomass cleared for land development than if forest age is not accounted for.

  15. Age-related and stand-wise estimates of carbon stocks and sequestration in the aboveground coarse wood biomass of wetland forests in the northern Pantanal, Brazil

    NASA Astrophysics Data System (ADS)

    Schöngart, J.; Arieira, J.; Felfili Fortes, C.; Cezarine de Arruda, E.; Nunes da Cunha, C.

    2011-11-01

    In this study we use allometric models combined with tree ring analysis to estimate carbon stocks and sequestration in the aboveground coarse wood biomass (AGWB) of wetland forests in the Pantanal, located in central South America. In four 1-ha plots in stands characterized by the pioneer tree species Vochysia divergens Pohl (Vochysiaceae) forest inventories (trees ≥10 cm diameter at breast height, D) have been performed and converted to estimates of AGWB by two allometric models using three independent parameters (D, tree height H and wood density ρ). We perform a propagation of measurement errors to estimate uncertainties in the estimates of AGWB. Carbon stocks of AGWB vary from 7.8 ± 1.5 to 97.2 ± 14.4 Mg C ha-1 between the four stands. From models relating tree ages determined by dendrochronological techniques to C-stocks in AGWB we derived estimates for C-sequestration which differs from 0.50 ± 0.03 to 3.34 ± 0.31 Mg C ha-1 yr-1. Maps based on geostatistic techniques indicate the heterogeneous spatial distribution of tree ages and C-stocks of the four studied stands. This distribution is the result of forest dynamics due to the colonizing and retreating of V. divergens and other species associated with pluriannual wet and dry episodes in the Pantanal, respectively. Such information is essential for the management of the cultural landscape of the Pantanal wetlands.

  16. The influece of forest gaps on some properties of humus in a managed beech forest, northern Iran

    NASA Astrophysics Data System (ADS)

    Vajari, K. A.

    2015-10-01

    The present research focuses on the effect of eight-year-old artificially created gaps on some properties of humus in managed beech-dominated stand in Hyrcanian forest of northern Iran. In this study, six-teen gaps were sampled in site and were classified into four classes (small, medium, large, and very large) with four replications for each. Humus sampling was carried out at the centre and at the cardinal points within each gap as well as in the adjacent closed stand, separately, as composite samples. The variables of organic carbon, P, K, pH, and total N were measured for each sample. It was found that the gap size had significant effect only on total N (%) and organic carbon (%) in beech stand. The amount of potassium clearly differed among three positions in beech forest. The adjacent stand had higher significantly potassium than center and edge of gaps. Different amount of potassium was detected in gap center and gap edge. Comparison of humus properties between gaps and its adjacent stand pointed to the higher amount of potassium in adjacent stand than that in gaps but there was no difference between them regarding other humus properties. According to the results, it can be concluded that there is relatively similar condition among gaps and closed adjacent stands in terms of humus properties eight years after logging in the beech stand.

  17. Aboveground carbon in Quebec forests: stock quantification at the provincial scale and assessment of temperature, precipitation and edaphic properties effects on the potential stand-level stocking.

    PubMed

    Duchesne, Louis; Houle, Daniel; Ouimet, Rock; Lambert, Marie-Claude; Logan, Travis

    2016-01-01

    Biological carbon sequestration by forest ecosystems plays an important role in the net balance of greenhouse gases, acting as a carbon sink for anthropogenic CO2 emissions. Nevertheless, relatively little is known about the abiotic environmental factors (including climate) that control carbon storage in temperate and boreal forests and consequently, about their potential response to climate changes. From a set of more than 94,000 forest inventory plots and a large set of spatial data on forest attributes interpreted from aerial photographs, we constructed a fine-resolution map (∼375 m) of the current carbon stock in aboveground live biomass in the 435,000 km(2) of managed forests in Quebec, Canada. Our analysis resulted in an area-weighted average aboveground carbon stock for productive forestland of 37.6 Mg ha(-1), which is lower than commonly reported values for similar environment. Models capable of predicting the influence of mean annual temperature, annual precipitation, and soil physical environment on maximum stand-level aboveground carbon stock (MSAC) were developed. These models were then used to project the future MSAC in response to climate change. Our results indicate that the MSAC was significantly related to both mean annual temperature and precipitation, or to the interaction of these variables, and suggest that Quebec's managed forests MSAC may increase by 20% by 2041-2070 in response to climate change. Along with changes in climate, the natural disturbance regime and forest management practices will nevertheless largely drive future carbon stock at the landscape scale. Overall, our results allow accurate accounting of carbon stock in aboveground live tree biomass of Quebec's forests, and provide a better understanding of possible feedbacks between climate change and carbon storage in temperate and boreal forests. PMID:26966680

  18. Aboveground carbon in Quebec forests: stock quantification at the provincial scale and assessment of temperature, precipitation and edaphic properties effects on the potential stand-level stocking

    PubMed Central

    Houle, Daniel; Ouimet, Rock; Lambert, Marie-Claude; Logan, Travis

    2016-01-01

    Biological carbon sequestration by forest ecosystems plays an important role in the net balance of greenhouse gases, acting as a carbon sink for anthropogenic CO2 emissions. Nevertheless, relatively little is known about the abiotic environmental factors (including climate) that control carbon storage in temperate and boreal forests and consequently, about their potential response to climate changes. From a set of more than 94,000 forest inventory plots and a large set of spatial data on forest attributes interpreted from aerial photographs, we constructed a fine-resolution map (∼375 m) of the current carbon stock in aboveground live biomass in the 435,000 km2 of managed forests in Quebec, Canada. Our analysis resulted in an area-weighted average aboveground carbon stock for productive forestland of 37.6 Mg ha−1, which is lower than commonly reported values for similar environment. Models capable of predicting the influence of mean annual temperature, annual precipitation, and soil physical environment on maximum stand-level aboveground carbon stock (MSAC) were developed. These models were then used to project the future MSAC in response to climate change. Our results indicate that the MSAC was significantly related to both mean annual temperature and precipitation, or to the interaction of these variables, and suggest that Quebec’s managed forests MSAC may increase by 20% by 2041–2070 in response to climate change. Along with changes in climate, the natural disturbance regime and forest management practices will nevertheless largely drive future carbon stock at the landscape scale. Overall, our results allow accurate accounting of carbon stock in aboveground live tree biomass of Quebec’s forests, and provide a better understanding of possible feedbacks between climate change and carbon storage in temperate and boreal forests. PMID:26966680

  19. Treatment of an old-growth stand and its effects on birds, ants, and large woody debris: A case study. Forest Service general technical report

    SciTech Connect

    Bull, E.L.; Torgersen, T.R.; Blumton, A.K.; McKenzie, C.M.; Wyland, D.S.

    1995-09-01

    An old-structure stand with large amounts of tree mortality was treated to accelerate regeneration and reduce fuel loads but still maintain its function as old growth for selected bird species. The smll-diameter (less than 15 inches in diameter at breast height (d.b.h.)), dead trees were removed as was some of the down wood less than 15 inches in diameter at the large end. All live trees of any size and all dead trees equal to or greater than 15 inches d.b.h. were retained. Vaux`s swifts (Chaetura vauxi) and pileated woodpeckers (Dryocopus pileatus) continued to use the stand after harvest for nesting and roosting. Brown-headed cowbirds (molothrus ater) were more than twice as common in the treated stand as in an adjacent unlogged, control stand. In a comparison before and after harvest in the treated stand, the number of logs increased, the number of logs with ants increased, but the percentage of logs with ants decreased.

  20. The evaluation of different forest structural indices to predict the stand aboveground biomass of even-aged Scotch pine (Pinus sylvestris L.) forests in Kunduz, Northern Turkey.

    PubMed

    Ercanli, İlker; Kahriman, Aydın

    2015-03-01

    We assessed the effect of stand structural diversity, including the Shannon, improved Shannon, Simpson, McIntosh, Margelef, and Berger-Parker indices, on stand aboveground biomass (AGB) and developed statistical prediction models for the stand AGB values, including stand structural diversity indices and some stand attributes. The AGB prediction model, including only stand attributes, accounted for 85 % of the total variance in AGB (R (2)) with an Akaike's information criterion (AIC) of 807.2407, Bayesian information criterion (BIC) of 809.5397, Schwarz Bayesian criterion (SBC) of 818.0426, and root mean square error (RMSE) of 38.529 Mg. After inclusion of the stand structural diversity into the model structure, considerable improvement was observed in statistical accuracy, including 97.5 % of the total variance in AGB, with an AIC of 614.1819, BIC of 617.1242, SBC of 633.0853, and RMSE of 15.8153 Mg. The predictive fitting results indicate that some indices describing the stand structural diversity can be employed as significant independent variables to predict the AGB production of the Scotch pine stand. Further, including the stand diversity indices in the AGB prediction model with the stand attributes provided important predictive contributions in estimating the total variance in AGB. PMID:25663395

  1. Structure and function of soil microbial community in artificially planted Sonneratia apetala and S. caseolaris forests at different stand ages in Shenzhen Bay, China.

    PubMed

    Yang, Q; Lei, A P; Li, F L; Liu, L N; Zan, Q J; Shin, P K S; Cheung, S G; Tam, N F Y

    2014-08-30

    The present study examined the relationships between soil characteristics, microbial community structure and function in the forests artificially planted with exotic Sonneratia apetala at stand ages of 1-, 2-, 7-, 10- and 14-years and Sonneratia caseolaris of 1-, 4-, 7-, 10- and 14-years in Futian National Nature Reserve, Shenzhen Bay, China. The 7-years old forests of both Sonneratia species reached peak growth and had the highest content of nitrogen and phosphorus, enzymatic activities, including dehydrogenase, cellulase, phosphatase, urease and ß-glucosidase, except arylsulphatase which increased continuously with stand ages. The microbial community structure reflected by phospholipid fatty acid (PLFA) profiles also reached the maximum value in the 7-years old forests and soil bacterial PLFAs in both forests were significantly higher than fungal PLFAs. The canonical correlation analysis revealed that differences in microbial structural variables were significantly correlated to the differences in their functional variables, and the highest correlation was found between the soil enzymatic activities and the content of carbon and nitrogen. PMID:24629377

  2. A Stand-Alone Demography and Landscape Structure Module for Earth System Models: Integration with Inventory Data from Temperate and Boreal Forests

    NASA Astrophysics Data System (ADS)

    Haverd, V. E.; Smith, B.; Nieradzik, L. P.; Briggs, P.

    2014-12-01

    Poorly constrained rates of biomass turnover are a key limitation of Earth system models (ESM). In light of this, we recently proposed a new approach encoded in a model called Populations-Order-Physiology (POP), for the simulation of woody ecosystem stand dynamics, demography and disturbance-mediated heterogeneity. POP is suitable for continental to global applications and designed for coupling to the terrestrial ecosystem component of any ESM. POP bridges the gap between first generation Dynamic Vegetation Models (DVMs) with simple large-area parameterisations of woody biomass (typically used in current ESMs) and complex second generation DVMs, that explicitly simulate demographic processes and landscape heterogeneity of forests. The key simplification in the POP approach, compared with second-generation DVMs, is to compute physiological processes such as assimilation at grid-scale (with CABLE or a similar land surface model), but to partition the grid-scale biomass increment among age classes defined at sub grid-scale, each subject to its own dynamics. POP was successfully demonstrated along a savanna transect in northern Australia, replicating the effects of strong rainfall and fire disturbance gradients on observed stand productivity and structure. Here, we extend the application of POP to a range of forest types around the globe, employing paired observations of stem biomass and density from forest inventory data to calibrate model parameters governing stand demography and biomass evolution. The calibrated POP model is then coupled to the CABLE land surface model and the combined model (CABLE-POP) is evaluated against leaf-stem allometry observations from forest stands ranging in age from 3 to 200 years. Results indicate that simulated biomass pools conform well with observed allometry. We conclude that POP represents an ecologically plausible and efficient alternative to large-area parameterisations of woody biomass turnover, typically used in current ESMs

  3. Old and Not-So-Old: Examining Changes in Forest Ecosystem Carbon Exchange With Stand Age in the Upper Midwest U.S.

    NASA Astrophysics Data System (ADS)

    Desai, A. R.; Cook, B.; Davis, K. J.; Bolstad, P.; Carey, E.; Martin, J.; Kreller, L.; Wang, W.

    2003-12-01

    Forest stand age is an important determinant of ecosystem carbon uptake. Though there are biometric measurements and ecological models for forests of all ages, there are few stand-scale eddy-flux measurements of net carbon exchange in older forests, though the number is increasing. In order to scale carbon fluxes from sites to regions, where stands of multiple ages may exist, it is necessary to measure to the effect of stand age on carbon exchange. Measuring the effect of stand age on carbon exchange is also necessary when trying to predict future or past carbon exchange (scaling across time). Many researchers have noted that site disturbance history is the fundamental factor in determining carbon uptake by forests over time scales of decades to centuries. The 8,500 ha Sylvania Wilderness in the upper peninsula of Michigan is one of several large tracts of old-growth forest in the Midwest. Trees range from 0-350 years old. Primary species are sugar maple, eastern hemlock and yellow birch. Catastrophic disturbance is rare. A research plot near the wilderness was established in late 2001 to measure the net ecosystem exchange (NEE) of carbon and water using eddy-flux, component flux and biometric methods. This site is part of the Chequamegon Ecosystem Atmosphere Study (ChEAS, http://cheas.psu.edu), a loose affiliation of researchers conducting carbon and water research in northern Wisconsin and upper Michigan. Another similar research plot within ChEAS and not far from Sylvania is the Willow Creek mature uplands site. This forest is about 70 years old and the primary species are sugar maple, basswood and green ash. The site had presettlement old-growth vegetation similar to what is currently seen in the Sylvania Wilderness. Thus, the carbon exchange seen at Sylvania may be representative of carbon uptake at Willow Creek had it not been logged in the early 20th century, and may also represent the future (or past) carbon uptake for similar forests in northern Wisconsin

  4. Productivity of aboveground coarse wood biomass and stand age related to soil hydrology of Amazonian forests in the Purus-Madeira interfluvial area

    NASA Astrophysics Data System (ADS)

    Cintra, B. B. L.; Schietti, J.; Emillio, T.; Martins, D.; Moulatlet, G.; Souza, P.; Levis, C.; Quesada, C. A.; Schöngart, J.

    2013-04-01

    The ongoing demand for information on forest productivity has increased the number of permanent monitoring plots across the Amazon. Those plots, however, do not comprise the whole diversity of forest types in the Amazon. The complex effects of soil, climate and hydrology on the productivity of seasonally waterlogged interfluvial wetland forests are still poorly understood. The presented study is the first field-based estimate for tree ages and wood biomass productivity in the vast interfluvial region between the Purus and Madeira rivers. We estimate stand age and wood biomass productivity by a combination of tree-ring data and allometric equations for biomass stocks of eight plots distributed along 600 km in the Purus-Madeira interfluvial area that is crossed by the BR-319 highway. We relate stand age and wood biomass productivity to hydrological and edaphic conditions. Mean productivity and stand age were 5.6 ± 1.1 Mg ha-1 yr-1 and 102 ± 18 yr, respectively. There is a strong relationship between tree age and diameter, as well as between mean diameter increment and mean wood density within a plot. Regarding the soil hydromorphic properties we find a positive correlation with wood biomass productivity and a negative relationship with stand age. Productivity also shows a positive correlation with the superficial phosphorus concentration. In addition, superficial phosphorus concentration increases with enhanced soil hydromorphic condition. We raise three hypotheses to explain these results: (1) the reduction of iron molecules on the saturated soils with plinthite layers close to the surface releases available phosphorous for the plants; (2) the poor structure of the saturated soils creates an environmental filter selecting tree species of faster growth rates and shorter life spans and (3) plant growth on saturated soil is favored during the dry season, since there should be low restrictions for soil water availability.

  5. Differences in Fine-Root Biomass of Trees and Understory Vegetation among Stand Types in Subtropical Forests

    PubMed Central

    Fu, Xiaoli; Wang, Jianlei; Di, Yuebao; Wang, Huimin

    2015-01-01

    Variation of total fine-root biomass among types of tree stands has previously been attributed to the characteristics of the stand layers. The effects of the understory vegetation on total fine-root biomass are less well studied. We examined the variation of total fine-root biomass in subtropical tree stands at two sites of Datian and Huitong in China. The two sites have similar humid monsoon climate but different soil organic carbon. One examination compared two categories of basal areas (high vs. low basal area) in stands of single species. A second examination compared single-species and mixed stands with comparable basal areas. Low basal area did not correlate with low total fine-root biomass in the single-species stands. The increase in seedling density but decrease in stem density for the low basal area stands at Datian and the quite similar stand structures for the basal-area contrast at Huitong helped in the lack of association between basal area and total fine-root biomass at the two sites, respectively. The mixed stands also did not yield higher total fine-root biomasses. In addition to the lack of niche complementarity between tree species, the differences in stem and seedling densities and the belowground competition between the tree and non-tree species also contributed to the similarity of the total fine-root biomasses in the mixed and single-species stands. Across stand types, the more fertile site Datian yielded higher tree, non-tree and total fine-root biomasses than Huitong. However, the contribution of non-tree fine-root biomass to the total fine-root biomass was higher at Huitong (29.4%) than that at Datian (16.7%). This study suggests that the variation of total fine-root biomass across stand types not only was associated with the characteristics of trees, but also may be highly dependent on the understory layer. PMID:26047358

  6. Ozone gradients in a spruce forest stand in relation to wind speed and time of the day

    NASA Astrophysics Data System (ADS)

    Pleijel, H.; Wallin, G.; Karlsson, P. E.; Skärby, L.

    Ozone concentrations were measured outside and inside a 60-year-old 15-20 m tall spruce forest at a wind-exposed forest edge in southwest Sweden, at 3 and 13 m height 15 m outside the forest, and at 3 and 13 m height inside the forest 45 m from the forest edge. Measurements at 3 m were made with three replicate tubes on each site, the replicates being separated by 10 m. In addition, horizontal and vertical wind speeds were measured at 8 m height outside and inside the forest. During daytime, the concentrations inside the forest were generally slightly lower. Negative ozone concentration gradients from the open field into the forest were observed at 3 m height when the wind speed was below approximately 1.5 m s -1. At very low wind speeds, mainly occurring during the night, the ozone concentrations at 3 m height were frequently higher inside the forest than outside the forest. This may be caused by a very large aerodynamic resistance to ozone deposition, due to very small air movements inside the forest under stable conditions. It is concluded that ozone uptake by the trees is likely to be very small at night, even if stomata are not entirely closed. Results from open-top chamber experiments are also discussed.

  7. Characterizing stand-level forest canopy cover and height using Landsat time series, samples of airborne LiDAR, and the Random Forest algorithm

    NASA Astrophysics Data System (ADS)

    Ahmed, Oumer S.; Franklin, Steven E.; Wulder, Michael A.; White, Joanne C.

    2015-03-01

    Many forest management activities, including the development of forest inventories, require spatially detailed forest canopy cover and height data. Among the various remote sensing technologies, LiDAR (Light Detection and Ranging) offers the most accurate and consistent means for obtaining reliable canopy structure measurements. A potential solution to reduce the cost of LiDAR data, is to integrate transects (samples) of LiDAR data with frequently acquired and spatially comprehensive optical remotely sensed data. Although multiple regression is commonly used for such modeling, often it does not fully capture the complex relationships between forest structure variables. This study investigates the potential of Random Forest (RF), a machine learning technique, to estimate LiDAR measured canopy structure using a time series of Landsat imagery. The study is implemented over a 2600 ha area of industrially managed coastal temperate forests on Vancouver Island, British Columbia, Canada. We implemented a trajectory-based approach to time series analysis that generates time since disturbance (TSD) and disturbance intensity information for each pixel and we used this information to stratify the forest land base into two strata: mature forests and young forests. Canopy cover and height for three forest classes (i.e. mature, young and mature and young (combined)) were modeled separately using multiple regression and Random Forest (RF) techniques. For all forest classes, the RF models provided improved estimates relative to the multiple regression models. The lowest validation error was obtained for the mature forest strata in a RF model (R2 = 0.88, RMSE = 2.39 m and bias = -0.16 for canopy height; R2 = 0.72, RMSE = 0.068% and bias = -0.0049 for canopy cover). This study demonstrates the value of using disturbance and successional history to inform estimates of canopy structure and obtain improved estimates of forest canopy cover and height using the RF algorithm.

  8. Fungi vectored by the bark beetle Ips typographus following hibernation under the bark of standing trees and in the forest litter.

    PubMed

    Persson, Ylva; Vasaitis, Rimvydas; Långström, Bo; Ohrn, Petter; Ihrmark, Katarina; Stenlid, Jan

    2009-10-01

    The bark beetle Ips typographus has different hibernation environments, under the bark of standing trees or in the forest litter, which is likely to affect the beetle-associated fungal flora. We isolated fungi from beetles, standing I. typographus-attacked trees, and forest litter below the attacked trees. Fungal identification was done using cultural and molecular methods. The results of the two methods in detecting fungal species were compared. Fungal communities associated with I. typographus differed considerably depending on the hibernation environment. In addition to seven taxa of known ophiostomoid I. typographus-associated fungi, we detected 18 ascomycetes and anamorphic fungi, five wood-decaying basidomycetes, 11 yeasts, and four zygomycetes. Of those, 14 fungal taxa were detected exclusively from beetles that hibernated under bark, and six taxa were detected exclusively from beetles hibernating in forest litter. The spruce pathogen, Ceratocystis polonica, was detected occasionally in bark, while another spruce pathogen, Grosmannia europhioides, was detected more often from beetles hibernating under the bark as compared to litter. The identification method had a significant impact on which taxa were detected. Rapidly growing fungal taxa, e.g. Penicillium, Trichoderma, and Ophiostoma, dominated pure culture isolations; while yeasts dominated the communities detected using molecular methods. The study also demonstrated low frequencies of tree pathogenic fungi carried by I. typographus during its outbreaks and that the beetle does not require them to successfully attack and kill trees. PMID:19444498

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  11. Satellite-based prediction of rainfall interception by tropical forest stands of a human-dominated landscape in Central Sulawesi, Indonesia

    NASA Astrophysics Data System (ADS)

    Nieschulze, Jens; Erasmi, Stefan; Dietz, Johannes; Hölscher, Dirk

    2009-01-01

    SummaryRainforest conversion to other land use types drastically alters the hydrological cycle in which changes in rainfall interception contribute significantly to the observed differences. However, little is known about the effects of more gradual changes in forest structure and at regional scales. We studied land use types ranging from natural forest over selectively-logged forest to cacao agroforest in a lower montane region in Central Sulawesi, Indonesia, and tested the suitability of high-resolution optical satellite imagery for modeling observed interception patterns. Investigated characteristics indicating canopy structure were mean and standard deviation of reflectance values, local maxima, and self-similarity measures based on the grey level co-occurrence matrix and geostatistical variogram analysis. Previously studied and published rainfall interception data comprised twelve plots and median values per land use type ranged from 30% in natural forest to 18% in cacao agroforests. A linear regression model with local maxima, mean contrast and normalized digital vegetation index (NDVI) as regressors was able to explain more than 84% ( Radj2) of the variation encountered in the data. Other investigated characteristics did not prove significant in the regression analysis. The model yielded stable results with respect to cross-validation and also produced realistic values and spatial patterns when applied at the landscape level (783.6 ha). High values of interception were rare and localized in natural forest stands distant to villages, whereas low interception characterized the intensively used sites close to settlements. We conclude that forest use intensity significantly reduced rainfall interception and satellite image analysis can successfully be applied for its regional prediction, and most forest in the study region has already been subject to human-induced structural changes.

  12. Spatial and seasonal variations of leaf area index (LAI) in subtropical secondary forests related to floristic composition and stand characters

    NASA Astrophysics Data System (ADS)

    Zhu, Wenjuan; Xiang, Wenhua; Pan, Qiong; Zeng, Yelin; Ouyang, Shuai; Lei, Pifeng; Deng, Xiangwen; Fang, Xi; Peng, Changhui

    2016-07-01

    Leaf area index (LAI) is an important parameter related to carbon, water, and energy exchange between canopy and atmosphere and is widely applied in process models that simulate production and hydrological cycles in forest ecosystems. However, fine-scale spatial heterogeneity of LAI and its controlling factors have yet to be fully understood in Chinese subtropical forests. We used hemispherical photography to measure LAI values in three subtropical forests (Pinus massoniana-Lithocarpus glaber coniferous and evergreen broadleaved mixed forests, Choerospondias axillaris deciduous broadleaved forests, and L. glaber-Cyclobalanopsis glauca evergreen broadleaved forests) from April 2014 to January 2015. Spatial heterogeneity of LAI and its controlling factors were analysed using geostatistical methods and the generalised additive models (GAMs) respectively. Our results showed that LAI values differed greatly in the three forests and their seasonal variations were consistent with plant phenology. LAI values exhibited strong spatial autocorrelation for the three forests measured in January and for the L. glaber-C. glauca forest in April, July, and October. Obvious patch distribution pattern of LAI values occurred in three forests during the non-growing period and this pattern gradually dwindled in the growing season. Stem number, crown coverage, proportion of evergreen conifer species on basal area basis, proportion of deciduous species on basal area basis, and forest types affected the spatial variations in LAI values in January, while stem number and proportion of deciduous species on basal area basis affected the spatial variations in LAI values in July. Floristic composition, spatial heterogeneity, and seasonal variations should be considered for sampling strategy in indirect LAI measurement and application of LAI to simulate functional processes in subtropical forests.

  13. Impact of land use change on atmospheric P inputs in a tropical dry forest

    NASA Astrophysics Data System (ADS)

    Das, Rishiraj; Lawrence, Deborah; D'Odorico, Paolo; Delonge, Marcia

    2011-03-01

    Forest canopies increase atmospheric inputs of nutrients to forest ecosystems by trapping dust and particulates. In tropical dry forests, this mechanism may contribute significant amounts of phosphorus, often a limiting nutrient in these ecosystems. Shifting cultivation may reduce the atmospheric inputs of phosphorus through the removal and restructuring of the forest canopy. We studied the impacts of land clearing by shifting cultivation in the southern Yucatan peninsula by measuring P in atmospheric bulk deposition and throughfall in two secondary forest stands and one mature forest stand to determine whether mature forests have greater throughfall P inputs than regenerating areas. From May to November 2007, we sampled rainfall in an open field and throughfall in three adjacent forest stands of different ages: 6 year old, 20 year old and mature (>60 year). We analyzed subsamples for inorganic and organic P. During the 7 month wet season, cumulative P input for the open field was 0.28 kg/ha, the 6 year stand accumulated 0.44 kg/ha, the 20 year stand accumulated 0.55 kg/ha and the mature stand accumulated 0.81 kg/ha. Organic P inputs were ˜50% of total P inputs in the open field, and 30-38% of total P inputs for the forest stands. The mature forest had significantly higher P concentrations and inputs than the open field or secondary forest stands, and forest stands had significantly greater P inputs than the open field, but there were no significant differences between the older and younger secondary forests. The repeated clearing of forests may thus reduce important P inputs to the ecosystem in the long-term.

  14. Harvesting impact on herbaceous understory, forest floor and top soil properties on skid road in a beech (Fagus orientalis Lipsky) stand.

    PubMed

    Demir, Murat; Makineci, E; Yilmaz, E

    2007-04-01

    In this study the impact of production work on the skid roads that have been carried out for many years by manpower animal power or machinery in a beech (Fagus orientalis Lipsky) stand have been examined. For this purpose, herbaceous understory, forest floor and soil samples were collected from the undisturbed area and the skid road. Weight per unit area (kg ha(-1)), organic matter ratio and moisture of forest floor and herbaceous understory were measured in undisturbed area and the skid road. Soil characteristics were examined at two different depths (0-5 cm and 5-10 cm). Percentages of sand, silt and clay electrical conductivity, weight of fine soil (<2 mm), soil fraction (>2 mm), root mass, organic carbon, moisture equivalent, total porosity, bulk density, moisture, compaction and pH values in the soil were determined. It has been determined that the amount of herbaceous understory and forest floor on the skid road decreased considerably compared to those of the undisturbed area. Parallel to this, the amount of organic matter in the herbaceous understory and the forest floor on the skid road decreased as well. It has been concluded that there are crucial differences between the values of compaction, bulk density fine soil weight, total porosity and moisture equivalent of the soil samples collected from both the skid road and the undisturbed area at both depth levels, as a result of compaction of the soil caused by harvesting works. PMID:17929761

  15. dNBR imagery and xeric pine-oak forest stand characteristics for fires of different severity in Great Smoky Mountains National Park

    NASA Astrophysics Data System (ADS)

    Abla, Scott A.

    Fire suppression has changed forest structure and composition on xeric sites in the southern Appalachians from open, pine-oak dominated stands to closed canopy, mixed hardwood stands. Improved understanding of fire-related tools and ecological responses will improve effectiveness of fire management aimed at restoring pre-fire suppression forest communities on these xeric sites. Although occurrence of fire is known to be related to ecosystem functioning, vegetation responses to multi-severity fires are not as well understood in the southern Appalachians. Additionally, the relationship between satellite imagery and ground-based methods for designating burn severity (post-fire term describing fire severity) are not established for the Great Smoky Mountains National Park (GSMNP). The purpose of my study was to (1) determine if burn severity designations were consistent between satellite imagery and ground-based methods, and (2) evaluate vegetation responses to different burn severities on xeric sites dominated by pine (Pinus) and oak ( Quercus) species in the GSMNP. Plots were randomly located using satellite-based (dNBR) burn severity maps. For part (1) of my study these sites were ground-truthed using the FIREMON Composite Burn Index (CBI). Initial scatter plots between CBI and dNBR indicated a saturated growth relationship and square-root transformed dNBR data were overall strongly correlated to ground-based ratings (CBI) for 169 total plots (p<0.001, R2=0.90). Strong relationships were found between CBI and dNBR across different xeric forest types and time since burn categories. For part (2) of my study, variables related to stand regeneration were measured at the ground, mid-story, and overstory layers across different burn severities for 48 plots. Differences in post-fire forest structure and composition across burn severity classifications were tested using analyses of variance and relationships between stand variables were evaluated using linear regression

  16. Difference of Ecosystem and Hydrological control on Long-term water quality between adjacent subcatchments in a forested catchment in central Japan

    NASA Astrophysics Data System (ADS)

    Katsuyama, M.; Iwasaki, K.; Nagano, R.; Takaki, K.; Tanaka, Y.

    2014-12-01

    We have been monitoring the water quality in the Kiryu Experimental Watershed (KEW; 5.99 ha), Japan, and four subcatchments for more than 20 years. The climate of KEW is warm temperate. The artificially planted Japanese Cypress around 1960 covers whole of the KEW. The geology of KEW is weathered granite. The concentrations of SiO2 and Na, which are mainly supplied from weathering processes, in streamwater were different between the catchments, and the difference was controlled by hydrological conditions in each catchment; in the catchment where shallow groundwater contribution to the streamflow is large, the concentrations were lower. Conversely, in the catchment where deep, bedrock groundwater contribution is large, these concentrations were higher. The K+ concentration which cycles between soil and plants showed clear seasonal variations and the differences between the catchments were small. Considering the long-term trend of streamwater chemistry, the electric conductivity (EC), Cl-, and SO42- concentrations have been gradually decreasing during recent 10 years in all catchments. On the other hand, the NO3- concentration has been commonly increasing in recent 5 years in all catchment. The difference of concentrations between the catchments were depending on the difference of the redox condition caused by soil sediment. One of the subcatchments experienced the disturbance in early 90's and subsequent increase of NO3- concentration, and the residence tine distribution shows the effects of the disturbance is still remaining. Recently, the disturbance is expanding in another subcatchment, and one of the reason of the disturbance is soil erosion. Moreover, the streamwater NO3- concentrations are also gradually increasing even in undisturbed catchments. These facts imply that this 50-year-old unmanaged artificial forest may start degrading, and the biogeochemical cycle may start changing. The long-term dynamics of streamwater chemistry is a good diagnosis tool of the

  17. Mountain Pine Beetle Impact on Stand-level Water Balance

    NASA Astrophysics Data System (ADS)

    Reilly, J. A.; Woods, S.

    2012-12-01

    The recent mountain pine beetle (MPB) epidemic has disturbed millions of hectares throughout the Rocky Mountain West. The most persistent effects of MPB infestation on the stand-level water balance are likely concomitant with the grey stage of the disturbance cycle. The grey stage occurs within 3 to 5 years of the initial infestation after the needles of an infected tree have turned red and fallen off due to tree death. Large numbers of grey-stage trees in a stand may remain on the landscape for up to 20 years, until windthrow or another disturbance sends them to the forest floor. The greater temporal persistence of the grey stage over antecedent stages suggested that an examination of the grey stage would best capture long-term effects of MPB disturbance on the forest water balance. In this study we hypothesized that changes to the forest canopy associated with MPB disturbance may affect the stand-level water balance. The needle loss and windthrow that follows MPB disturbance is expected to increase the amount of precipitation reaching the forest floor. Additionally, overstory evapotranspiration (ET) demand is expected to decrease as MPB-induced tree mortality increases within disturbed stands. The expected cumulative effect of MPB disturbance on the stand-level water balance is an increase in soil moisture due to increased precipitation inputs and reduced overstory ET. This study was conducted in Lubrecht Experimental Forest and adjacent Bureau of Land Management areas near Missoula, Montana. Sub-canopy measurements of soil moisture, precipitation (rain and snow water equivalent), overstory transpiration and micro-meteorological data (net radiation, temperature, wind speed, etc.) were collected in three 50 x 50 meter plots. The plots consisted of a uniform stand of grey-stage lodgepole pine, a uniform stand of non-infested lodgepole pine, and a recent clear-cut stand, which served as a control unit. Water balances for each stand were constructed using a mass

  18. Dendrochronology-based stand growth estimation of Larix olgensis forest in relation with climate on the eastern slope of Changbai Mountain, NE China

    NASA Astrophysics Data System (ADS)

    Lin, Bo; Xu, Qianqian; Liu, Wenhui; Zhang, Guochun; Xu, Qiongyao; Liu, Qijing

    2013-12-01

    The eastern slope of Changbai Mountain is characterized by pure larch forest ( Larix olgensis) with little human disturbance. Response of tree growth to climate in this area remains unknown. Meanwhile, little is known about how climate variations affect the biomass increase which could be recognized as a three-dimensional tree growth index. The objective of this study is to investigate the climate effects on the radial and biomass growth of larch on eastern slope of Changbai Mountain. Tree-ring width chronologies and mean annual biomass increment were established using tree-ring data. We used correlation analysis and multiple regression analysis to explore the relationship between larch growth and climatic factors from 1957 to 2009. Results show that tree-ring growth and mean annual biomass increment were primarily and significantly affected by previous year climatic variables with slight difference among months. Temperatures were more consistently and strongly correlated to the chronologies and mean annual biomass increment than was precipitation. Temperature is the main factor limiting larch growth on Changbai Mountain and the ongoing climate warming may accelerate the growth of the species. The current stand biomass of the area was 240.72 Mg·ha-1 and the annual stand biomass increment in 2009 was 2.91 Mg·ha-1. In conclusion, the old-growth forest in the study area is still accumulating carbon efficiently.

  19. Living near the edge: Being close to mature forest increases the rate of succession in beetle communities.

    PubMed

    Fountain-Jones, Nicholas M; Jordan, Gregory J; Baker, Thomas P; Balmer, Jayne M; Wardlaw, Tim; Baker, Susan C

    2015-04-01

    In increasingly fragmented landscapes, it is important to understand how mature forest affects adjacent secondary forest (forest influence). Forest influence on ecological succession of beetle communities is largely unknown. We investigated succession and forest influence using 235 m long transects across boundaries between mature and secondary forest at 15 sites, sampling a chronosequence of three forest age classes (5-10, 23- 29, and 42-46 years since clear-cutting) in tall eucalypt forest in Tasmania, Australia. Our results showed that ground-dwelling beetle communities showed strong successional changes, and in the oldest secondary forests, species considered indicators of mature forest had recolonized to abundance levels similar to those observed within adjacent mature forest stands. However, species composition also showed forest influence gradients in all age classes. Forest influence was estimated to extend 13 m and 20 m in the youngest and intermediate-aged secondary forests, respectively. However, the estimated effect extended to at least 176 m in the oldest secondary forest. Our environmental modeling suggests that leaf litter, microclimate, and soil variables were all important in explaining the spatial variation in beetle assemblages, and the relative importance of factors varied between secondary forest age classes. Mature-forest beetle communities can recolonize successfully from the edge, and our results provide a basis for land managers to build mature habitat connectivity into forest mosaics typical of production forests. Our results also indicate the importance of forest influence in determining potential conservation value of older secondary forest for beetles. PMID:26214924

  20. A significant carbon sink in temperate forests in Beijing: based on 20-year field measurements in three stands

    NASA Astrophysics Data System (ADS)

    Zhu, J.

    2015-12-01

    Numerous efforts have been made to characterize the forest carbon (C) cycles and stocks. However, long-term observation-based quantification on each component of the forest C cycle and its change is still lacking. We measured C stocks and fluxes in three permanent temperate forest plots (birch, oak and pine forest plots) during 2011-2014 and calculated the changes of the C cycle components related to the measurements during 1992-1994 in Mt. Dongling, Beijing, China. Our results showed that forest net primary production in birch, oak and pine plots were 5.32, 4.53 and 6.73 Mg C ha-1 yr-1, respectively. The corresponding net ecosystem production were 0.12, 0.43 and 3.53 Mg C ha-1 yr-1. The C stocks and fluxes in 2011-2014 were significantly larger than those in 1992-1994: the biomass C densities in birch, oak and pine plots increased from 50.0, 37.7 and 54.0 Mg C ha-1 in 1994 to 101.5, 77.3 and 110.9 Mg C ha-1 in 2014; soil organic C densities from 207.0, 239.1 and 231.7 Mg C ha-1 to 214.8, 241.7 and 238.4 Mg C ha-1; and soil heterotrophic respiration from 2.78, 3.49 and 1.81 Mg C ha-1 yr-1 to 5.20, 4.10 and 3.20 Mg C ha-1 yr-1. These results suggest that the mountainous temperate forest ecosystems are a carbon sink in the recent two decades. These observations of C densities and fluxes provided field-based data for long-term study of C cycling in temperate forest ecosystems.

  1. A significant carbon sink in temperate forests in Beijing: based on 20-year field measurements in three stands.

    PubMed

    Zhu, JianXiao; Hu, XueYang; Yao, Hui; Liu, GuoHua; Ji, ChenJun; Fang, JingYun

    2015-11-01

    Numerous efforts have been made to characterize forest carbon (C) cycles and stocks in various ecosystems. However, long-term observation on each component of the forest C cycle is still lacking. We measured C stocks and fluxes in three permanent temperate forest plots (birch, oak and pine forest) during 2011–2014, and calculated the changes of the components of the C cycle related to the measurements during 1992–1994 at Mt. Dongling, Beijing, China. Forest net primary production in birch, oak, and pine plots was 5.32, 4.53, and 6.73 Mg C ha-1 a-1, respectively. Corresponding net ecosystem production was 0.12, 0.43, and 3.53 Mg C ha-1 a-1. The C stocks and fluxes in 2011–2014 were significantly larger than those in 1992–1994 in which the biomass C densities in birch, oak, and pine plots increased from 50.0, 37.7, and 54.0 Mg C ha-1 in 1994 to 101.5, 77.3, and 110.9 Mg C ha-1 in 2014; soil organic C densities increased from 207.0, 239.1, and 231.7 Mg C ha-1 to 214.8, 241.7, and 238.4 Mg C ha-1; and soil heterotrophic respiration increased from 2.78, 3.49, and 1.81 Mg C ha-1 a-1 to 5.20, 4.10, and 3.20 Mg C ha-1 a-1. These results suggest that the mountainous temperate forest ecosystems in Beijing have served as a carbon sink in the last two decades. These observations of C stocks and fluxes provided field-based data for a long-term study of C cycling in temperate forest ecosystems. PMID:26501378

  2. Variable strength of forest stand attributes and weather conditions on the questing activity of Ixodes ricinus ticks over years in managed forests.

    PubMed

    Lauterbach, Ralf; Wells, Konstans; O'Hara, Robert B; Kalko, Elisabeth K V; Renner, Swen C

    2013-01-01

    Given the ever-increasing human impact through land use and climate change on the environment, we crucially need to achieve a better understanding of those factors that influence the questing activity of ixodid ticks, a major disease-transmitting vector in temperate forests. We investigated variation in the relative questing nymph densities of Ixodes ricinus in differently managed forest types for three years (2008-2010) in SW Germany by drag sampling. We used a hierarchical Bayesian modeling approach to examine the relative effects of habitat and weather and to consider possible nested structures of habitat and climate forces. The questing activity of nymphs was considerably larger in young forest successional stages of thicket compared with pole wood and timber stages. Questing nymph density increased markedly with milder winter temperatures. Generally, the relative strength of the various environmental forces on questing nymph density differed across years. In particular, winter temperature had a negative effect on tick activity across sites in 2008 in contrast to the overall effect of temperature across years. Our results suggest that forest management practices have important impacts on questing nymph density. Variable weather conditions, however, might override the effects of forest management practices on the fluctuations and dynamics of tick populations and activity over years, in particular, the preceding winter temperatures. Therefore, robust predictions and the detection of possible interactions and nested structures of habitat and climate forces can only be quantified through the collection of long-term data. Such data are particularly important with regard to future scenarios of forest management and climate warming. PMID:23372852

  3. Variable Strength of Forest Stand Attributes and Weather Conditions on the Questing Activity of Ixodes ricinus Ticks over Years in Managed Forests

    PubMed Central

    Lauterbach, Ralf; Wells, Konstans; O'Hara, Robert B.; Renner, Swen C.

    2013-01-01

    Given the ever-increasing human impact through land use and climate change on the environment, we crucially need to achieve a better understanding of those factors that influence the questing activity of ixodid ticks, a major disease-transmitting vector in temperate forests. We investigated variation in the relative questing nymph densities of Ixodes ricinus in differently managed forest types for three years (2008–2010) in SW Germany by drag sampling. We used a hierarchical Bayesian modeling approach to examine the relative effects of habitat and weather and to consider possible nested structures of habitat and climate forces. The questing activity of nymphs was considerably larger in young forest successional stages of thicket compared with pole wood and timber stages. Questing nymph density increased markedly with milder winter temperatures. Generally, the relative strength of the various environmental forces on questing nymph density differed across years. In particular, winter temperature had a negative effect on tick activity across sites in 2008 in contrast to the overall effect of temperature across years. Our results suggest that forest management practices have important impacts on questing nymph density. Variable weather conditions, however, might override the effects of forest management practices on the fluctuations and dynamics of tick populations and activity over years, in particular, the preceding winter temperatures. Therefore, robust predictions and the detection of possible interactions and nested structures of habitat and climate forces can only be quantified through the collection of long-term data. Such data are particularly important with regard to future scenarios of forest management and climate warming. PMID:23372852

  4. Impacts of repeated timber skidding on the chemical properties of topsoil, herbaceous cover and forest floor in an eastern beech (Fagus orientalis Lipsky) stand.

    PubMed

    Demir, Murat; Makineci, Ender; Comez, Aydin; Yilmaz, Ersel

    2010-07-01

    In this study, long-term timber skidding effects on herbaceous understory forest floor and soil were investigated on a skid road in a stand of the eastern beech (Fagus orientalis Lipsky). For this purpose, herbaceous understory forest floor and soil samples were collected from the skid road and from an undisturbed area used as a control plot. The mass (kg ha(-1)) of herbaceous and forest floor samples was determined, and soil characteristics were examined at two depths (0-5 cm and 5-10 cm). We quantified sand, silt and clay content, as well as bulk density compaction, pH, and organic carbon content in soil samples. The quantities of N, K, P, Na, Ca, Mg, Fe, Mn, Zn and Cu were determined in all herbaceous cover forest floor and soil samples. The quantities of Na, Fe, Zn, Cu and Mn in herbaceous understory samples from the skid road were considerably higher than those in the undisturbed area, while the quantity of Mg was considerably lower. These differences could have been caused by decreased herbaceous cover in addition to variations in the properties of the forest floor and soil after skidding. A lower amount of forest floor on the skid road was the result of skidding and harvesting activities. Mg and Zn contents in forest floor samples were found to be considerably lower for the skid road than for the undisturbed area. No significant differences were found in soil chemical properties (quantities of N, P, K, Na, Ca, Mg, Fe, Zn, Cu and Mn) at the 0-5 cm soil depth. Important differences exist between soil quantities of Mg at a 5-10 cm depth on the skid road and in undisturbed areas. Both 0-5 cm and 5-10 cm soil depths, the average penetrometer resistance values for the skid road was higher than for the undisturbed area. This result shows that the compaction caused by skidding is maintained to depth of 10 cm. Skid road soil showed higher bulk density values than undisturbed areas because of compaction. PMID:21186723

  5. 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.

  6. The role of clay minerals and fulvic acid to the complexation of Na, Mg, and Ca in stream flows from adjacent forested head watersheds composed of different vegetation

    NASA Astrophysics Data System (ADS)

    Terajima, Tomomi; Moriizumi, Mihoko; Nakamura, Tomohiro

    2010-05-01

    In order to understand the complexation and flow process in metal elements under a fresh water environment, discharges of Na, Mg, and Ca were measured in streams of adjacent forested head watersheds composed of coniferous evergreen- and deciduous broad leaf- trees. Total elements (T-Na, T-Mg, and T-Ca) and ions (Na+, Mg2+, and Ca2+) in stream flows which passed through 0.45 μm filters were measured with an ICP and Ion-chromatograph. The remainders of total elements and ions were equated with complex compounds. Then the discharges of Si and fulvic acid, which respectively are the representatives of ligands by clay minerals and humic substances, provided the relationship between the compound discharges and the complexation process of the above metal elements. Even if Na, Mg, and Ca are believed to be mostly free ions in fresh water environments, the rates of the compounds to the total elements ranged 10 to 40 % in the coniferous watershed and 20 to 60 % in the deciduous watersheds. The compounds sometimes occupied more than half of the total elements; this was predominant in the deciduous watershed. These mean that the discharge of compounds is not negligible in watershed hydrology. Possible complexation processes in metal elements are #1) Hydration, #2) Adsorption or substitution with clay minerals, #3) Mineral complex, #4) Adsorption with humic substances as represented by fulvic acid, and #5) Chelate with organic acids as oxalate, formic acid, and pyrrole. Under fresh water environments, #2 and #4 must be the most potential processes of the complexation in metal elements. The relationship between the compounds, Si, and fulvic acid, therefore, supplies useful information to presume the status of the compounds. The compounds-Si relations in both watersheds showed linear correlations (r=0.79 to 0.99) for a stream base flow and stream flow in a small rainstorm. The linear correlations, however, occurred only for the stream flow in the compounds-Si relations at a big

  7. Retreating or Standing: Responses of Forest Species and Steppe Species to Climate Change in Arid Eastern Central Asia

    PubMed Central

    Zhang, Hong-Xiang; Zhang, Ming-Li; Sanderson, Stewart C.

    2013-01-01

    Background The temperature in arid Eastern Central Asia is projected to increase in the future, accompanied by increased variability of precipitation. To investigate the impacts of climate change on plant species in this area, we selected two widespread species as candidates, Clematis sibirica and C. songorica, from montane coniferous forest and arid steppe habitats respectively. Methodology/Principal Findings We employed a combined approach of molecular phylogeography and species distribution modelling (SDM) to predict the future responses of these two species to climate change, utilizing evidence of responses from the past. Genetic data for C. sibirica shows a significant phylogeographical signal (NST > FST, P<0.05) and demographic contraction during the glacial-interglacial cycles in the Pleistocene. This forest species would likely experience range reduction, though without genetic loss, in the face of future climate change. In contrast, SDMs predict that C. songorica, a steppe species, should maintain a consistently stable potential distribution under the Last Glacial Maximum (LGM) and the future climatic conditions referring to its existing potential distribution. Molecular results indicate that the presence of significant phylogeographical signal in this steppe species is rejected and this species contains a high level of genetic differentiation among populations in cpDNA, likely benefiting from stable habitats over a lengthy time period. Conclusions/Significance Evidence from the molecular phylogeography of these two species, the forest species is more sensitive to past climate changes than the steppe species. SDMs predict that the forest species will face the challenge of potential range contraction in the future more than the steppe species. This provides a perspective on ecological management in arid Eastern Central Asia, indicating that increased attention should be paid to montane forest species, due to their high sensitivity to disturbance. PMID

  8. Stemwood production patterns in ponderosa pine: Effects of stand dynamics and other factors. Forest Service research paper

    SciTech Connect

    Arbaugh, M.J.; Peterson, D.L.

    1993-05-01

    The growth patterns of vertical stems in nine ponderosa pines from a stand in the southern Sierra Nevada were analyzed for recent changes due to stand dominance position, age, climate, and ozone exposure. Large positive correlations were found between increments in volume growth and basal area at d.b.h. The results indicated that patterns of wood distribution along the bole were associated with age, competitive position, and release from competition. A multiple regression model using winter and spring precipitation adequately explained short-term growth fluctuations during 1920-1955 and predicted growth during 1956-1985 for the trees as a group. A prominent feature of all volume, basal area, and ring width series was a growth response to a selective harvest in 1965. Increments in gross volume increased througout the bole of all trees but declined for thinning. This increasing trend continued for young and dominant trees but declined for older nondominant trees.

  9. Response of the engraver beetle, IPS perturbatus, to semiochemicals in white spruce stands of interior Alaska. Forest Service research paper

    SciTech Connect

    Werner, R.A.

    1993-05-01

    Field tests on the efficacy of various scolytid bark beetle pheromones to attract Ips perturbatus (Eichhoff) were conducted from 1977 through 1992 in stands of white spruce (Picea glauca (Moench) Voss) in interior Alaska. Several pheromones attracted high numbers of I. perturbatus and species of the predator Thanasimus to baited funnel traps. Test results also indicated that attacks by I. perturbatus may be deferred by certain semiochemicals.

  10. The effects of phytophagous insects on water and soil nutrient concentrations and fluxes through forest stands of the Level II monitoring network in the UK.

    PubMed

    Pitman, R M; Vanguelova, E I; Benham, S E

    2010-12-01

    The effects of insect defoliators on throughfall and soil nutrient fluxes were studied in coniferous and deciduous stands at five UK intensive monitoring plots (1998 to 2008). Links were found between the dissolved organic carbon (DOC), nitrogen (N) and potassium (K) fluxes through the forest system to biological activity within the canopy. Underlying soil type determined the leaching or accumulation of these elements. Under oak, monitored at two sites, frass from caterpillars of Tortrix viridana and Operophtera brumata added direct deposition of ~16kgha(-1)extra N during defoliation. Peaks of nitrate (NO(3)-N) flux between 5 and 9kgha(-1) (×5 usual winter values) were recorded in consecutive years in shallow soil waters. Synchronous rises in deep soil NO(3)-N fluxes at the Grizedale sandy site indicate downward flushing, not seen at the clay site. Under three Sitka spruce stands, generation of honeydew (DOC) was attributed to two aphid species (Elatobium abietinum and Cinara pilicornis) with distinctive feeding strategies. Throughfall DOC showed mean annual fluxes (6 seasons) ~45-60kgha(-1) compared with rainfall values of 14-22kgha(-1). Increases of total N in throughfall and NO(3)-N fluxes in shallow soil solution were detected - soil water fluxes reached 8kgha(-1) in Llyn Brianne, ~25kgha(-1) in Tummel, and ~40kg NO(3)-Nha(-1) in Coalburn. At Tummel, on sandy soil, NO(3)-N leaching showed increased concentration at depth, attributed to microbiological activity within the soil. By contrast, at Coalburn and Llyn Brianne, sites on peaty gleys, soil water NO(3)-N was retained mostly within the humus layer. Soil type is thus key to predicting N movement and retention patterns. These long term analyses show important direct and indirect effects of phytophagous insects in forest ecosystems, on above and below ground processes affecting tree growth, soil condition, vegetation and water quality. PMID:20961599

  11. The state of microbial complexes in soils of forest ecosystems after fires and defoliation of stands by gypsy moths

    NASA Astrophysics Data System (ADS)

    Bogorodskaya, A. V.; Baranchikov, Yu. N.; Ivanova, G. A.

    2009-03-01

    The state of microbial cenoses in the soils of forest ecosystems damaged by fires of different strengths and gypsy moth outbreaks (Central Siberia) was assessed by the intensity of the basal respiration, the content of carbon of the microbial biomass, and the microbial metabolic quotient. The degree of the disturbance of the microbial cenoses in the soils under pine forests after fires was higher than that in the soils under the forests defoliated by gypsy moths. The greatest changes of the microbial complexes were recorded after the fires of high and medium intensity. In the litters, the content of the microbial biomass, the intensity of basal respiration, and the microbial metabolic quotient value were restored on the fifth year after the fires, whereas in the upper (0-10 cm) soil layer, these parameters still differed from those in the control variant, especially after the highly intense fires. After the weak fires, the ecophysiological state of the microbial complexes was restored within two-three years.

  12. Effects of edaphic factors on the tree stand diversity in a tropical forest of Sierra Madre del Sur, Mexico

    NASA Astrophysics Data System (ADS)

    Kurzmeier, S.; Wiedemann, T.; Biber, P.; Schad, P.; Krasilnikov, P. V.

    2012-08-01

    Two sites with similar environmental parameters, except for the edaphic factor, were selected in the mountainous tropical forest of southern Mexico. Site 1 was established on an Alisol; site 2, on a Phaeozem. Representative soil profiles were examined on each of the sites, and topsoil was sampled on a regular grid pattern. The soil of site 2 was richer in organic matter and major nutrients and had a less acid reaction than the soil of site 1. The species diversity of the trees at site 2 (30 species) was higher than that at site 1 (17 species). The species compositions of the trees were different on the two soils: there were only six species in common for both sites. The coefficients of species similarity on the sites were low. We concluded that the presence of different soils within the same type of forest ecosystem increases its β-diversity. The examination of edaphic preferences of the species showed that Alstonia longifolia and Thouinidium decandrum preferred rich soils, Inga punctata and Ocotea sinuata preferred poor soils, and Cupania dentata and Hamelia patens did not display preferences in the studied range of soil properties. Thus, the spatial variability of the soil properties affect the spatial pattern of tree species in the studied tropical forest ecosystems.

  13. Estimation of whole-tree and stand-level methane emissions from the stems of Alnus japonica in a cool-temperate forested peatland

    NASA Astrophysics Data System (ADS)

    Terazawa, Kazuhiko; Yamada, Kenji; Sakata, Tadashi; Nakamura, Takatoshi; Ishizuka, Shigehiro

    2016-04-01

    We measured methane (CH4) fluxes at the stem surfaces of canopy trees in a forested peatland of northern Japan to estimate: 1) the CH4 emission rates from the stems of individual trees and 2) the stem CH4 emission rates at the stand level. The study site was located ca. 1 km south of Lake Tofutsu, a brackish lake in eastern Hokkaido. An experimental plot was established in an area dominated by Alnus japonica trees. For seven A. japonica, the stem CH4 fluxes were measured using a static closed-chamber method. Three of the sample trees were used to estimate the whole-tree stem CH4 emissions. The CH4 flux was measured at six heights (0.15 - 5.15 m above the ground at 1 m intervals) on the stem of each tree, using a scaffold constructed beside the tree. The stand-level stem CH4 emissions were estimated from the CH4 fluxes measured 0.15 m above the ground; the relationship between stem height and CH4 flux and the relationship between diameter at breast height and whole-tree CH4 emissions were determined. Stem CH4 emission rates were highest at the lowest measurement position on the stem (height 0.15 m), and decreased with stem height for all measurements. Nevertheless, significant CH4 emissions were detected 5.15 m above the ground. The relationship between stem height and CH4 emissions fit a power function. The estimated CH4 emission rate from the stem surface of an individual tree was 1.91 ± 1.24 and 0.68 ± 0.18 mg tree‑1 h‑1 for late-August and mid-September, respectively. The estimated stem CH4 emissions at the stand level varied seasonally, with the highest rate of 556 mg ha‑1 h‑1 in September.

  14. Fusion of full waveform Laserscanning and airborne hyperspectral remote sensing data for the characterization of forest stands

    NASA Astrophysics Data System (ADS)

    Buddenbaum, Henning

    2010-05-01

    Hyperspectral data offer the maximum spectral reflectance information available from remote sensing. A continuous spectrum of narrow bands with near-laboratory quality is recorded for each pixel. This data can be used for difficult classification tasks or detailed quantitative analyses, e.g. determination of chlorophyll or water content in leaves. But in forested areas, discerning between different age classes of the same tree species is still error-prone. Airborne Laserscanning measures the three-dimensional position of every reflecting object and can be used to map tree heights and crown volumes. These are highly correlated with tree age and timber volume. In addition, Laserscanner data can be used to differentiate between coniferous and deciduous trees either by analysing crown shapes that lead to different surface roughness or by exploiting the intensity information of laser echoes from the crowns. But a more detailed determination of tree species is not possible using Laserscanning alone. The combination of hyperspectral and Laserscanning data promises the possibility to map both tree species and age classes. We used a HyMap data set with 122 bands recorded in 2003 and a full waveform Laserscanning recorded in 2005 in the same area, Idarwald Forest in South-western Germany. To combine both datasets, we defined voxels above the HyMap pixels, containing the mean laser intensity in slices of 50 cm height. These voxels form a second hyperspectral dataset of 76 bands with the same geometry as the HyMap image, so that they could be fused into a 198 band image. The joined image performed better in a classification of tree species and age classes than each of the single images and also better than a dataset consisting of the hyperspectral image and a tree height map. Apart from classification, it can also be used to derive tree heights and crown base heights and to estimate biomass, leaf area index and timber volume and to characterize the vertical forest structure.

  15. Soil respiration following partial stand disturbance by tree girdling reveals a rapid rebound within a three-year period in a temperate forest

    NASA Astrophysics Data System (ADS)

    Levy, J.; Schuster, W.; Griffin, K. L.

    2012-12-01

    Disturbance events can greatly impact carbon cycling and subsequently alter the carbon storage service of a forest. The resulting atmosphere-biosphere feedback through CO2 makes understanding the carbon cycle response imperative for climate change research. The aim of this study was to examine the temporal response of soil respiration after a partial stand disturbance and to reassess the autotrophic contribution to soil respiration after three years at the Black Rock Forest (southeastern NY, USA). Tree girdling was used to initiate disturbance and create the following treatments: control (C), girdling all non-oaks (NO), girdling half of the oak trees (O50), girdling all the oaks (OG), and girdling all trees (ALL). Soil respiration was measured for three consecutive years. Respiratory rates on O50, OG, and ALL plots declined for two years following girdling before attaining a full rebound of belowground activity in the third year. Soil respiration on NO was similar to C for the duration of the study. The short lived respiratory response on O50, OG, and ALL aligns with patterns of reported NEP recovery after a pest or pathogen attack in other forested systems and suggests that belowground activity is resilient to disturbance. Respiratory responses among the various treatments were not proportional to the degree of disturbance experienced and varied through time. Based on the results from the first year of girdling, we previously estimated the autotrophic component to be 50 % of the total respiratory flux but continued declines in soil respiration rates into the second year provided an opportunity to make a more accurate estimate of 58 %.

  16. Reforestation Sites Show Similar and Nested AMF Communities to an Adjacent Pristine Forest in a Tropical Mountain Area of South Ecuador

    PubMed Central

    Haug, Ingeborg; Setaro, Sabrina; Suárez, Juan Pablo

    2013-01-01

    Arbuscular mycorrhizae are important for growth and survival of tropical trees. We studied the community of arbuscular mycorrhizal fungi in a tropical mountain rain forest and in neighbouring reforestation plots in the area of Reserva Biológica San Francisco (South Ecuador). The arbuscular mycorrhizal fungi were analysed with molecular methods sequencing part of the 18 S rDNA. The sequences were classified as Operational Taxonomic Units (OTUs). We found high fungal species richness with OTUs belonging to Glomerales, Diversisporales and Archaeosporales. Despite intensive sampling, the rarefaction curves are still unsaturated for the pristine forest and the reforestation plots. The communities consisted of few frequent and many rare species. No specific interactions are recognizable. The plant individuals are associated with one to ten arbuscular mycorrhizal fungi and mostly with one to four. The fungal compositions associated with single plant individuals show a great variability and variety within one plant species. Planted and naturally occurring plants show high similarities in their fungal communities. Pristine forest and reforestation plots showed similar richness, similar diversity and a significantly nested structure of plant-AMF community. The results indicate that small-scale fragmentation presently found in this area has not destroyed the natural AMF community, at least yet. Thus, the regeneration potential of natural forest vegetation at the tested sites is not inhibited by a lack of appropriate mycobionts. PMID:23671682

  17. Reforestation sites show similar and nested AMF communities to an adjacent pristine forest in a tropical mountain area of South Ecuador.

    PubMed

    Haug, Ingeborg; Setaro, Sabrina; Suárez, Juan Pablo

    2013-01-01

    Arbuscular mycorrhizae are important for growth and survival of tropical trees. We studied the community of arbuscular mycorrhizal fungi in a tropical mountain rain forest and in neighbouring reforestation plots in the area of Reserva Biológica San Francisco (South Ecuador). The arbuscular mycorrhizal fungi were analysed with molecular methods sequencing part of the 18 S rDNA. The sequences were classified as Operational Taxonomic Units (OTUs). We found high fungal species richness with OTUs belonging to Glomerales, Diversisporales and Archaeosporales. Despite intensive sampling, the rarefaction curves are still unsaturated for the pristine forest and the reforestation plots. The communities consisted of few frequent and many rare species. No specific interactions are recognizable. The plant individuals are associated with one to ten arbuscular mycorrhizal fungi and mostly with one to four. The fungal compositions associated with single plant individuals show a great variability and variety within one plant species. Planted and naturally occurring plants show high similarities in their fungal communities. Pristine forest and reforestation plots showed similar richness, similar diversity and a significantly nested structure of plant-AMF community. The results indicate that small-scale fragmentation presently found in this area has not destroyed the natural AMF community, at least yet. Thus, the regeneration potential of natural forest vegetation at the tested sites is not inhibited by a lack of appropriate mycobionts. PMID:23671682

  18. Comparison of height-accumulation and volume-equation methods for estimating tree and stand volumes. Forest Service research note

    SciTech Connect

    Ferguson, R.B.; Baldwin, V.C.

    1995-09-01

    Estimating tree and stand volume in mature plantations is time consuming, involving much manpower and equipment; however, several sampling and volume-prediction techniques are available. This study showed that a well-constructed, volume-equation method yields estimates comparable to those of the often more time-consuming, hight-accumulation method, even though the latter should be more accurate for any individual tree. Plot volumes were estimated by both methods in a remeasurement of trees in a 40-plot, planted slash pine thinning study. The mean percent age difference in total volume, inside bark, between the two methods ranged from 1 to 2.5 percent across all the plots; differences outside bark ranged from 7 to 10 percent. The results were similar when the effecs of site, plot mean values, or tree-by-tree comparisons were incorporated.

  19. Spatial Scales of Genetic Structure in Free-Standing and Strangler Figs (Ficus, Moraceae) Inhabiting Neotropical Forests.

    PubMed

    Heer, Katrin; Kalko, Elisabeth K V; Albrecht, Larissa; García-Villacorta, Roosevelt; Staeps, Felix C; Herre, Edward Allen; Dick, Christopher W

    2015-01-01

    Wind-borne pollinating wasps (Agaonidae) can transport fig (Ficus sp., Moraceae) pollen over enormous distances (> 100 km). Because of their extensive breeding areas, Neotropical figs are expected to exhibit weak patterns of genetic structure at local and regional scales. We evaluated genetic structure at the regional to continental scale (Panama, Costa Rica, and Peru) for the free-standing fig species Ficus insipida. Genetic differentiation was detected only at distances > 300 km (Jost´s Dest = 0.68 ± 0.07 & FST = 0.30 ± 0.03 between Mesoamerican and Amazonian sites) and evidence for phylogeographic structure (RST>permuted RST) was only significant in comparisons between Central and South America. Further, we assessed local scale spatial genetic structure (SGS, d ≤ 8 km) in Panama and developed an agent-based model parameterized with data from F. insipida to estimate minimum pollination distances, which determine the contribution of pollen dispersal on SGS. The local scale data for F. insipida was compared to SGS data collected for an additional free-standing fig, F. yoponensis (subgenus Pharmacosycea), and two species of strangler figs, F. citrifolia and F. obtusifolia (subgenus Urostigma) sampled in Panama. All four species displayed significant SGS (mean Sp = 0.014 ± 0.012). Model simulations indicated that most pollination events likely occur at distances > > 1 km, largely ruling out spatially limited pollen dispersal as the determinant of SGS in F. insipida and, by extension, the other fig species. Our results are consistent with the view that Ficus develops fine-scale SGS primarily as a result of localized seed dispersal and/or clumped seedling establishment despite extensive long-distance pollen dispersal. We discuss several ecological and life history factors that could have species- or subgenus-specific impacts on the genetic structure of Neotropical figs. PMID:26226482

  20. Spatial Scales of Genetic Structure in Free-Standing and Strangler Figs (Ficus, Moraceae) Inhabiting Neotropical Forests

    PubMed Central

    Heer, Katrin; Albrecht, Larissa; García-Villacorta, Roosevelt; Staeps, Felix C.; Herre, Edward Allen; Dick, Christopher W.

    2015-01-01

    Wind-borne pollinating wasps (Agaonidae) can transport fig (Ficus sp., Moraceae) pollen over enormous distances (> 100 km). Because of their extensive breeding areas, Neotropical figs are expected to exhibit weak patterns of genetic structure at local and regional scales. We evaluated genetic structure at the regional to continental scale (Panama, Costa Rica, and Peru) for the free-standing fig species Ficus insipida. Genetic differentiation was detected only at distances > 300 km (Jost´s Dest = 0.68 ± 0.07 & FST = 0.30 ± 0.03 between Mesoamerican and Amazonian sites) and evidence for phylogeographic structure (RST>>permuted RST) was only significant in comparisons between Central and South America. Further, we assessed local scale spatial genetic structure (SGS, d ≤ 8 km) in Panama and developed an agent-based model parameterized with data from F. insipida to estimate minimum pollination distances, which determine the contribution of pollen dispersal on SGS. The local scale data for F. insipida was compared to SGS data collected for an additional free-standing fig, F. yoponensis (subgenus Pharmacosycea), and two species of strangler figs, F. citrifolia and F. obtusifolia (subgenus Urostigma) sampled in Panama. All four species displayed significant SGS (mean Sp = 0.014 ± 0.012). Model simulations indicated that most pollination events likely occur at distances > > 1 km, largely ruling out spatially limited pollen dispersal as the determinant of SGS in F. insipida and, by extension, the other fig species. Our results are consistent with the view that Ficus develops fine-scale SGS primarily as a result of localized seed dispersal and/or clumped seedling establishment despite extensive long-distance pollen dispersal. We discuss several ecological and life history factors that could have species- or subgenus-specific impacts on the genetic structure of Neotropical figs. PMID:26226482

  1. Modelling diameter distributions of two-cohort forest stands with various proportions of dominant species: a two-component mixture model approach.

    PubMed

    Podlaski, Rafał; Roesch, Francis A

    2014-03-01

    In recent years finite-mixture models have been employed to approximate and model empirical diameter at breast height (DBH) distributions. We used two-component mixtures of either the Weibull distribution or the gamma distribution for describing the DBH distributions of mixed-species, two-cohort forest stands, to analyse the relationships between the DBH components, age cohorts and dominant species, and to assess the significance of differences between the mixture distributions and the kernel density estimates. The data consisted of plots from the Świętokrzyski National Park (Central Poland) and areas close to and including the North Carolina section of the Great Smoky Mountains National Park (USA; southern Appalachians). The fit of the mixture Weibull model to empirical DBH distributions had a precision similar to that of the mixture gamma model, slightly less accurate estimate was obtained with the kernel density estimator. Generally, in the two-cohort, two-storied, multi-species stands in the southern Appalachians, the two-component DBH structure was associated with age cohort and dominant species. The 1st DBH component of the mixture model was associated with the 1st dominant species sp1 occurred in young age cohort (e.g., sweetgum, eastern hemlock); and to a lesser degree, the 2nd DBH component was associated with the 2nd dominant species sp2 occurred in old age cohort (e.g., loblolly pine, red maple). In two-cohort, partly multilayered, stands in the Świętokrzyski National Park, the DBH structure was usually associated with only age cohorts (two dominant species often occurred in both young and old age cohorts). When empirical DBH distributions representing stands of complex structure are approximated using mixture models, the convergence of the estimation process is often significantly dependent on the starting strategies. Depending on the number of DBHs measured, three methods for choosing the initial values are recommended: min.k/max.k, 0.5/1.5/mean

  2. Application of δ13C and δ15N isotopic signatures of organic matter fractions sequentially separated from adjacent arable and forest soils to identify carbon stabilization mechanisms

    NASA Astrophysics Data System (ADS)

    Kayler, Z. E.; Kaiser, M.; Gessler, A.; Ellerbrock, R. H.; Sommer, M.

    2011-03-01

    Identifying the chemical mechanisms behind soil carbon bound in organo-mineral complexes is necessary to determine the degree to which soil organic carbon is stabilized belowground. We used the δ13C and δ15N isotopic signatures from two organic matter (OM) fractions from soil to identify the likely binding mechanisms involved. We used OM fractions hypothesized to contain carbon stabilized through organo-mineral complexes: (1) OM separated chemically with sodium pyrophosphate (OM(PY)) and (2) OM stabilized in microstructures found in the chemical extraction residue (OM(ER)). Furthermore, because the OM fractions were separated from five different soils with paired forest and arable land use histories, we could address the impact of land use change on carbon binding and processing mechanisms within these soils. We used partial least squares regression to analyze patterns in the isotopic signature of OM with established proxies of different binding mechanisms. Parsing soil OM into different fractions is a systematic method of dissection, however, we are primarily interested in how OM is bound in soil as a whole, requiring a means of re-assembly. Thus, we implemented the recent zonal framework described by Kleber et al. (2007) to relate our findings to undisturbed soil. The δ15N signature of OM fractions served as a reliable indicator for microbial processed carbon in both arable and forest land use types. The δ13C signature of OM fractions in arable sites did not correlate well with proxies of soil mineral properties while a consistent pattern of enrichment was seen in the δ13C of OM fractions in the forest sites. We found a significant difference in δ13C of pooled OM fractions between the forest and arable land use type although it was relatively small (<1‰). We found different binding mechanisms predominate in each land use type. The isotopic signatures of OM fractions from arable soils were highly related to the clay and silt size particles amount while

  3. Fusion of LiDAR and Imagery to Estimate Stand-level Tree Mortality Following Wildfire in a Coast Redwood Forest

    NASA Astrophysics Data System (ADS)

    Bishop, B. D.; Dietterick, B. C.; White, R. A.; Mastin, T.

    2013-12-01

    Discrete-return airborne LiDAR and digital orthophotography are commonly used to assess the condition of vegetation, including change detection following disturbance events, such as wildland fire. Forest managers have a need for information about fire effects and the spatial distribution of mortality following wildfire, but direct assessment from the field is time-consuming and expensive. Remote sensing may be used to estimate varying levels of mortality and provide a more efficient, timely, scalable, and potentially more cost-effective means for post-fire assessment. Similar past studies have generally used an index of fire 'severity' rather than estimating mortality directly. While useful, estimates of severity are not generally sufficient to make stand-level forest management decisions about post-fire response. This study modeled mortality of trees following the Lockheed fire, which burned 3,163 ha in the Santa Cruz Mountains in California from August 12-23, 2009. All trees in forty-seven 0.08 ha continuous forest inventory plots were assessed in the field for three years following the fire. Plot percent mortality of trees 25.4 cm DBH and greater was sorted into three categories: <25%, 25-50%, and >50%. A variety of predictor variables derived from pre- and post-fire airborne LiDAR and 1m resolution color infrared aerial imagery (NAIP) were evaluated. A model using four variables: the normalized difference vegetation index (NDVI) from 2010 NAIP imagery, change in ratio of 95th percentile to mean height, and change in percent of points in two height bins, 11-12 and 14-15m, classified plots with 83% accuracy. All plots in the most severe class (mortality >50%) were correctly classified. Models with variables derived from post-fire LiDAR alone, and NDVI alone, were also examined, and had overall accuracies of 76.6 and 68.1%, respectively. These findings indicate that remote sensing data can be used to estimate and map the distribution of tree mortality following

  4. Modeling Fire Severity in Black Spruce Stands in the Alaskan Boreal Forest Using Spectral and Non-Spectral Geospatial Data

    NASA Technical Reports Server (NTRS)

    Barrett, K.; Kasischke, E. S.; McGuire, A. D.; Turetsky, M. R.; Kane, E. S.

    2010-01-01

    Biomass burning in the Alaskan interior is already a major disturbance and source of carbon emissions, and is likely to increase in response to the warming and drying predicted for the future climate. In addition to quantifying changes to the spatial and temporal patterns of burned areas, observing variations in severity is the key to studying the impact of changes to the fire regime on carbon cycling, energy budgets, and post-fire succession. Remote sensing indices of fire severity have not consistently been well-correlated with in situ observations of important severity characteristics in Alaskan black spruce stands, including depth of burning of the surface organic layer. The incorporation of ancillary data such as in situ observations and GIS layers with spectral data from Landsat TM/ETM+ greatly improved efforts to map the reduction of the organic layer in burned black spruce stands. Using a regression tree approach, the R2 of the organic layer depth reduction models was 0.60 and 0.55 (pb0.01) for relative and absolute depth reduction, respectively. All of the independent variables used by the regression tree to estimate burn depth can be obtained independently of field observations. Implementation of a gradient boosting algorithm improved the R2 to 0.80 and 0.79 (pb0.01) for absolute and relative organic layer depth reduction, respectively. Independent variables used in the regression tree model of burn depth included topographic position, remote sensing indices related to soil and vegetation characteristics, timing of the fire event, and meteorological data. Post-fire organic layer depth characteristics are determined for a large (N200,000 ha) fire to identify areas that are potentially vulnerable to a shift in post-fire succession. This application showed that 12% of this fire event experienced fire severe enough to support a change in post-fire succession. We conclude that non-parametric models and ancillary data are useful in the modeling of the surface

  5. Modeling fire severity in black spruce stands in the Alaskan boreal forest using spectral and non-spectral geospatial data

    USGS Publications Warehouse

    Barrett, K.; Kasischke, E.S.; McGuire, A.D.; Turetsky, M.R.; Kane, E.S.

    2010-01-01

    Biomass burning in the Alaskan interior is already a major disturbance and source of carbon emissions, and is likely to increase in response to the warming and drying predicted for the future climate. In addition to quantifying changes to the spatial and temporal patterns of burned areas, observing variations in severity is the key to studying the impact of changes to the fire regime on carbon cycling, energy budgets, and post-fire succession. Remote sensing indices of fire severity have not consistently been well-correlated with in situ observations of important severity characteristics in Alaskan black spruce stands, including depth of burning of the surface organic layer. The incorporation of ancillary data such as in situ observations and GIS layers with spectral data from Landsat TM/ETM+ greatly improved efforts to map the reduction of the organic layer in burned black spruce stands. Using a regression tree approach, the R2 of the organic layer depth reduction models was 0.60 and 0.55 (p < 0.01) for relative and absolute depth reduction, respectively. All of the independent variables used by the regression tree to estimate burn depth can be obtained independently of field observations. Implementation of a gradient boosting algorithm improved the R2 to 0.80 and 0.79 (p < 0.01) for absolute and relative organic layer depth reduction, respectively. Independent variables used in the regression tree model of burn depth included topographic position, remote sensing indices related to soil and vegetation characteristics, timing of the fire event, and meteorological data. Post-fire organic layer depth characteristics are determined for a large (> 200,000 ha) fire to identify areas that are potentially vulnerable to a shift in post-fire succession. This application showed that 12% of this fire event experienced fire severe enough to support a change in post-fire succession. We conclude that non-parametric models and ancillary data are useful in the modeling of the

  6. [Correlations between standing trees trunk decay degree and soil physical-chemical properties in Korean pine-broadleaved mixed forest in Xiao Xing'an Mountains of Northeast China].

    PubMed

    Sun, Tian-Yong; Wang, Li-Hai; Sun, Mo-Long

    2013-07-01

    Standing trees decay often causes vast loss of timber resources. To investigate the correlations between the standing trees decay and the site conditions is of importance to scientifically and reasonably manage forests and to decrease wood resources loss. By using Resistograph and meter ruler, a measurement was made on the decay degree of the trunk near root and the diameter at breast height (DBH) of 15 mature Korean pine standing trees in a Korean pine-broadleaved mixed forest in Xiao Xing' an Mountains in May, 2011. In the meantime, soil samples were collected from the root zones of standing trees and the upslope and downslope 5 meters away from the trunks, respectively. Five physical-chemical properties including moisture content, bulk density, total porosity, pH value, and organic matter content of the soil samples were tested. The regression equations concerning the trunk decay degree of the standing trees, their DBH, and the 5 soil properties were established. The results showed that the trunk decay degree of the mature Korean pine standing trees had higher correlations with the bulk density, total porosity, pH value, and organic matter content (R = 0.687), and significant positive correlation with the moisture content (R = 0.507) of the soils at the root zones of standing trees, but less correlation with the 5 properties of the soils at both upslope and downslope 5 meters away from the trunks. The trunk decay degree was decreased when the soil moisture content was below 18.4%. No significant correlation was observed between the trunk decay degree of mature Korean pine standing trees and the tree age. PMID:24175511

  7. Spatial distributions of forest stand condition, vegetation ground cover, and soil erosion for evaluating the linkages of sediment transport from hillslopes to streams in headwater catchments

    NASA Astrophysics Data System (ADS)

    Gomi, T.; Kumakura, A.; Mizugaki, S.; Takahisa, F.; Ishikawa, Y.; Uchiyama, Y.

    2011-12-01

    We investigated soil erosion and resultant fine sediment transport in headwater catchments with heterogeneous spatial patterns of forest stand condition and vegetation ground cover. The study was conducted in 7 and 5 ha headwater catchments (Watersheds No.3 and No.4, respectively) in Tanzawa mountains area, 60 km of southwest of Tokyo, Japan. We selected 53 points located within catchments including near stream channels to the ridge line. A 0.5 x 0.5 m plot (1m x 1m) were selected in each point for investigating vegetation biomass, litter cover, soil erosion (e.g., soil pedestal), overstory vegetation condition (type of forest and canopy openness), and soil physical properties (e.g., soil bulk density and particle size). We assumed that high of soil pedestal indicated short term soil erosions by soil splash and related down slope soil movement. Percentages of bare soil in No. 3 tend to greater than ones in No.4. In addition, bare soil slope tended to distributed lower part of hillslopes with > 45° in gradient, where the soil can be transported to streams. Because of the high soil erosion rate in No.3 catchment, suspended sediment and bedload transport in No.3 tended to be greater ones in No.4 catchment. Fingerprinting approach using activities of fallout radionuclides (caesium-137 and excess lead-210) confirmed that some of the fine sediment transport at associated with hillslope soil surface erosion. Findings of this study suggested that processes of catchment scale fine sediment depending on the linkages between hillslope and channels.

  8. Applicability of non-destructive substitutes for leaf area in different stands of Norway spruce (Picea abies L. Karst.) focusing on traditional forest crown measures

    PubMed Central

    Laubhann, Daniel; Eckmüllner, Otto; Sterba, Hubert

    2010-01-01

    Since individual tree leaf area is an important measure for productivity as well as for site occupancy, it is of high interest in many studies about forest growth. The exact determination of leaf area is nearly impossible. Thus, a common way to get information about leaf area is to use substitutes. These substitutes are often variables which are collected in a destructive way which is not feasible for long term studies. Therefore, this study aimed at testing the applicability of using substitutes for leaf area which could be collected in a non-destructive way, namely crown surface area and crown projection area. In 8 stands of Norway spruce (Picea abies L. Karst.), divided into three age classes and two thinning treatments, a total of 156 trees were felled in order to test the relationship between leaf area and crown surface area and crown projection area, respectively. Individual tree leaf area of the felled sample trees was estimated by 3P-branch sampling with an accuracy of ±10%. Crown projection area and crown surface area were compared with other, more commonly used, but destructive predictors of leaf area, namely sapwood area at different heights on the bole. Our investigations confirmed findings of several studies that sapwood area is the most precise measure for leaf area because of the high correlation between sapwood area and the leaf area. But behind sapwood area at crown base and sapwood area at three tenth of the tree height the predictive ability of crown surface area was ranked third and even better than that of sapwood area at breast height (R2 = 0.656 compared with 0.600). Within the stands leaf area is proportional to crown surface area. Using the pooled data of all stands a mixed model approach showed that additionally to crown surface area dominant height and diameter at breast height (dbh) improved the leaf area estimates. Thus, taking dominant height and dbh into account, crown surface area can be recommended for estimating the leaf area of

  9. Gaseous polycyclic aromatic hydrocarbon concentrations are higher in urban forests than adjacent open areas during summer but not in winter--Exploratory study.

    PubMed

    Viippola, Viljami; Rantalainen, Anna-Lea; Yli-Pelkonen, Vesa; Tervo, Peatta; Setälä, Heikki

    2016-01-01

    While the potential of plants to uptake polycyclic aromatic hydrocarbons (PAHs) is widely acknowledged, empirical evidence of the effects of this process on local atmospheric PAH concentrations and human health is tenuous. We measured gaseous PAH concentrations using passive samplers in urban tree-covered areas and adjacent open, treeless areas in a near-road environment in Finland to gain information on the ability of urban vegetation to improve air quality. The ability of urban, mostly deciduous, vegetation to affect PAHs was season dependent: during summer, concentrations were significantly higher in tree-covered areas, while in the fall, concentrations in open areas exceeded those in tree-covered areas. During winter, concentrations in tree-covered areas were either lower or did not differ from those in open areas. Results of this study imply that the commonly believed notion that trees unequivocally improve air quality does not apply to PAHs studied here. PMID:26412199

  10. Is the simple auger coring method reliable for below-ground standing biomass estimation in Eucalyptus forest plantations?

    PubMed Central

    Levillain, Joseph; Thongo M'Bou, Armel; Deleporte, Philippe; Saint-André, Laurent; Jourdan, Christophe

    2011-01-01

    Background and Aims Despite their importance for plant production, estimations of below-ground biomass and its distribution in the soil are still difficult and time consuming, and no single reliable methodology is available for different root types. To identify the best method for root biomass estimations, four different methods, with labour requirements, were tested at the same location. Methods The four methods, applied in a 6-year-old Eucalyptus plantation in Congo, were based on different soil sampling volumes: auger (8 cm in diameter), monolith (25 × 25 cm quadrate), half Voronoi trench (1·5 m3) and a full Voronoi trench (3 m3), chosen as the reference method. Key Results With the reference method (0–1m deep), fine-root biomass (FRB, diameter <2 mm) was estimated at 1·8 t ha−1, medium-root biomass (MRB diameter 2–10 mm) at 2·0 t ha−1, coarse-root biomass (CRB, diameter >10 mm) at 5·6 t ha−1 and stump biomass at 6·8 t ha−1. Total below-ground biomass was estimated at 16·2 t ha−1 (root : shoot ratio equal to 0·23) for this 800 tree ha−1 eucalypt plantation density. The density of FRB was very high (0·56 t ha−1) in the top soil horizon (0–3 cm layer) and decreased greatly (0·3 t ha−1) with depth (50–100 cm). Without labour requirement considerations, no significant differences were found between the four methods for FRB and MRB; however, CRB was better estimated by the half and full Voronoi trenches. When labour requirements were considered, the most effective method was auger coring for FRB, whereas the half and full Voronoi trenches were the most appropriate methods for MRB and CRB, respectively. Conclusions As CRB combined with stumps amounted to 78 % of total below-ground biomass, a full Voronoi trench is strongly recommended when estimating total standing root biomass. Conversely, for FRB estimation, auger coring is recommended with a design pattern accounting for the spatial variability of fine-root distribution. PMID

  11. Scaling Erica arborea transpiration from trees up to the stand using auxiliary micrometeorological information in a wax myrtle-tree heath cloud forest (La Gomera, Canary Islands).

    PubMed

    Regalado, Carlos M; Ritter, Axel

    2013-09-01

    We investigate evapotranspiration, sap flow and top soil water content variations in a wax myrtle-tree heath ('fayal-brezal' in Spanish) cloud forest in the Garajonay National Park (La Gomera, Canary Islands) over a 1-year period. We provide transpiration estimates for one of the representative species, the shrubby needle-like Erica arborea L., present in this relict subtropical forest. An ad hoc tree up to the stand scaling method that combines the sap flow and auxiliary reference evapotranspiration data is illustrated, showing to be useful when sap flow in a limited number of trees has been monitored. Individual daily-based scaling curves of the Gompertz type were necessary to explain the observed sap flow variability in E. arborea during the 1-year period investigated (r(2) ≥ 0.953 with mode of r(2) = 0.9999). The mean daily sap flow of an E. arborea individual amounted to 8.37 ± 5.65 kg day(-1) tree(-1), with a maximum of 20.48 kg day(-1) tree(-1), yielding an annual total of 3052.89 kg tree(-1). A comparison of the computed daily transpiration with the continuous micrometeorological time series monitored in the studied plot suggested that solar radiation was the main driving force of transpiration in E. arborea (cross correlation index = 0.94). Fog may also affect tree transpiration via its reduction of radiation and temperature, such that during foggy periods the mean daily water loss estimate of E. arborea was 5.35 ± 4.30 kg day(-1) tree(-1), which sharply contrasted with the 2.4-fold average transpiration values obtained for fog-free days, i.e., 12.81 ± 4.33 kg day(-1) tree(-1). The annual water balance rendered a 288 mm year(-1) water input to the forest and evidenced the need for accurately quantifying the contribution of fog water dripping from the canopy. PMID:24072518

  12. Vitality and chemistry of roots of red spruce in forest floors of stands with a gradient of soil Al/Ca ratios in the northeastern United States

    USGS Publications Warehouse

    Wargo, P.M.; Vogt, K.; Vogt, D.; Holifield, Q.; Tilley, J.; Lawrence, G.; David, M.

    2003-01-01

    Number of living root tips per branch, percent dead roots, percent mycorrhizae and mycorrhizal morphotype, response of woody roots to wounding and colonization by fungi, and concentrations of starch, soluble sugars, phenols, percent C and N and C/N ratio, and Al Ca, Fe, K, Mg, Mn, and P were measured for 2 consecutive years in roots of red spruce (Picea rubens Sarg.) in stands in the northeastern United States (nine in 1993 and two additional in 1994) dominated by red spruce and with a gradient of forest floor exchangeable Al/Ca ratios. Root vitality was measured for nonwoody and coarse woody roots; chemical variables were measured for nonwoody (<1 mm), fine woody (1 to <2 mm), and coarse woody (2 to <5 mm) roots. There were significant differences among sites for all variables, particularly in 1993, although few were related to the Al/Ca ratio gradient. Percent mycorrhizae decreased, while some morphotypes increased or decreased as the Al/Ca ratio increased. In nonwoody roots, N increased as the Al/Ca ratio increased. Most sampled trees appeared to be in good or fair health, suggesting that an adverse response of these root variables to high Al concentrations may be apparent only after a significant change in crown health.

  13. Measuring Gap Fraction, Element Clumping Index and LAI in Sierra Forest Stands Using a Full-Waveform Ground-Based Lidar

    NASA Technical Reports Server (NTRS)

    Zhao, Feng; Strahler, Alan H.; Crystal L. Schaaf; Yao, Tian; Yang, Xiaoyuan; Wang, Zhuosen; Schull, Mitchell A.; Roman, Miguel O.; Woodcock, Curtis E.; Olofsson, Pontus; Ni-Meister, Wenge; Jupp, David L. B.; Lovell, Jenny L.; Culvenor, Darius S.; Newnham, Glenn J.

    2012-01-01

    The Echidna Validation Instrument (EVI), a ground-based, near-infrared (1064 nm) scanning lidar, provides gap fraction measurements, element clumping index measurements, effective leaf area index (LAIe) and leaf area index (LAI) measurements that are statistically similar to those from hemispherical photos. In this research, a new method integrating the range dimension is presented for retrieving element clumping index using a unique series of images of gap probability (Pgap) with range from EVI. From these images, we identified connected gap components and found the approximate physical, rather than angular, size of connected gap component. We conducted trials at 30 plots within six conifer stands of varying height and stocking densities in the Sierra National Forest, CA, in August 2008. The element clumping index measurements retrieved from EVI Pgap image series for the hinge angle region are highly consistent (R2=0.866) with those of hemispherical photos. Furthermore, the information contained in connected gap component size profiles does account for the difference between our method and gap-size distribution theory based method, suggesting a new perspective to measure element clumping index with EVI Pgap image series and also a potential advantage of three dimensional Lidar data for element clumping index retrieval. Therefore further exploration is required for better characterization of clumped condition from EVI Pgap image series.

  14. Phosphorus input through fog deposition in a dry tropical forest

    NASA Astrophysics Data System (ADS)

    Vandecar, Karen L.; Runyan, Christiane W.; D'Odorico, Paolo; Lawrence, Deborah; Schmook, Birgit; Das, Rishiraj

    2015-12-01

    In many tropical forests, where phosphorus (P) is considered a limiting nutrient, atmospheric deposition can contribute significantly to available P. Previous studies have shown that P inputs from atmospheric deposition are enhanced by plant canopies. This effect is explained as the result of increased deposition of P-rich aerosol particles (dry deposition) and fog droplets (fog or "occult" deposition) onto leaf surfaces. Here we studied the importance of fog as a source of P to a P-limited dry tropical forest. Throughout an 80 day period during the dry season when fog is most common, we sampled fog water and bulk precipitation in a clearing and measured leaf wetness and throughfall in an adjacent secondary and mature forest stand. During the study period, total P (PT) concentrations in fog water ranged from 0.15 to 6.40 mg/L, on average fourteenfold greater than PT concentrations in bulk precipitation (0.011 to 0.451 mg/L), and sixfold and sevenfold greater than throughfall PT concentrations in the secondary and mature forest stands, respectively (0.007 to 1.319 mg/L; 0.009 to 0.443 mg/L). Based on leaf area index, the frequency of fog deposition, and amount of water deposited per fog event, we estimate that fog delivers a maximum of 1.01 kg/ha/yr to secondary forest stands and 1.75 kg/ha/yr to mature forest stands, compared to 0.88 kg/ha/yr to secondary forest stands and 1.98 kg/ha/yr to mature forest stands via throughfall (wet + dry deposition) and stemflow. Thus, fog deposition may contribute substantially to available P in tropical dry forests.

  15. Application of a two-dimensional model to describe the CO2 exchange between a spatially non-uniform forest stand and the atmosphere

    NASA Astrophysics Data System (ADS)

    Mukhartova, Yulia; Olchev, Alexander; Shapkina, Natalia

    2014-05-01

    Within the framework of the study a two dimensional hydrodynamic high-resolution model of the energy, H2O, CO2 turbulent exchange was developed and applied to describe effect of the horizontal and vertical heterogeneity of a forest canopy on CO2exchange between soil surface, forest stand and the atmosphere under different weather conditions. Most attention in the study was paid to analyze the influence of forest clearing, windthrow of different sizes, forest edges, etc. on turbulent exchange rate and CO2 flux partitioning between forest overstorey, understorey and soil surface. The modeling experiments were provided under different wind conditions, thermal stratification of the atmospheric boundary layer, incoming solar radiation, etc. To quantify effect of spatial heterogeneity on total ecosystem fluxes the modeling results were compared with CO2 fluxes modeled for a spatially uniform forest canopy under similar ambient conditions. The averaged system of hydrodynamic equations is used for calculating the components of the mean velocity →V = {V1, V2}: ( ( ) ) δVi+ V δVi= - 1-δδP- - -δ- δ E - K δVi-+ δVj- + F, δVi = 0, δt jδxj ρ0 δxi δxj ij δxj δxi i δxi where E is the turbulent kinetic energy (TKE), K is the turbulent diffusivity, δP is the deviation of pressure from the hydrostatic distribution and ρ0→F is the averaged force of air flow interaction with vegetation. F→ was parameterized as →F = -cd ·LAD ·| | ||V→||·→V, where cd is the drag coefficient and LAD is the leaf area density. The turbulent diffusivity K can be expressed by means of TKE and the velocity of TKE dissipation ɛ as follows: K = CμE2ɛ-1, where Cμ is the proportionality coefficient. One of the ways to obtain E and ɛ is to solve the additional system of two differential equations of diffusion-transport type: ( ) ( ) δE- -δE- -δ- -K-δE- δ-ϕ δϕ- -δ- K-δϕ -ϕ ( 1 2 ) δt +Vjδxj = δxi σE δxi +PE - ɛ, δt +Vj δxj = δxi σϕδxi +E C ϕPE - C

  16. Variability in net ecosystem exchange from hourly to inter-annual time scales at adjacent pine and hardwood forests: a wavelet analysis.

    PubMed

    Stoy, Paul C; Katul, Gabriel G; Siqueira, Mario B S; Juang, Jehn-Yih; McCarthy, Heather R; Kim, Hyun-Seok; Oishi, A Christopher; Oren, Ram

    2005-07-01

    Orthonormal wavelet transformation (OWT) is a computationally efficient technique for quantifying underlying frequencies in nonstationary and gap-infested time series, such as eddy-covariance-measured net ecosystem exchange of CO2 (NEE). We employed OWT to analyze the frequency characteristics of synchronously measured and modeled NEE at adjacent pine (PP) and hardwood (HW) ecosystems. Wavelet cospectral analysis showed that NEE at PP was more correlated to light and vapor pressure deficit at the daily time scale, and NEE at HW was more correlated to leaf area index (LAI) and temperature, especially soil temperature, at seasonal time scales. Models were required to disentangle the impacts of environmental drivers on the components of NEE, ecosystem carbon assimilation (Ac) and ecosystem respiration (RE). Sensitivity analyses revealed that using air temperature rather than soil temperature in RE models improved the modeled wavelet spectral frequency response on time scales longer than 1 day at both ecosystems. Including LAI improved RE model fit on seasonal time scales at HW, and incorporating parameter variability improved the RE model response at annual time scales at both ecosystems. Resolving variability in canopy conductance, rather than leaf-internal CO2, was more important for modeling Ac at both ecosystems. The PP ecosystem was more sensitive to hydrologic variables that regulate canopy conductance: vapor pressure deficit on weekly time scales and soil moisture on seasonal to interannual time scales. The HW ecosystem was sensitive to water limitation on weekly time scales. A combination of intrinsic drought sensitivity and non-conservative water use at PP was the basis for this response. At both ecosystems, incorporating variability in LAI was required for an accurate spectral representation of modeled NEE. However, nonlinearities imposed by canopy light attenuation were of little importance to spectral fit. The OWT revealed similarities and differences in

  17. SAR backscatter from coniferous forest gaps

    NASA Technical Reports Server (NTRS)

    Day, John L.; Davis, Frank W.

    1992-01-01

    A study is in progress comparing Airborne Synthetic Aperture Radar (AIRSAR) backscatter from coniferous forest plots containing gaps to backscatter from adjacent gap-free plots. Issues discussed are how do gaps in the range of 400 to 1600 sq m (approximately 4-14 pixels at intermediate incidence angles) affect forest backscatter statistics and what incidence angles, wavelengths, and polarizations are most sensitive to forest gaps. In order to visualize the slant-range imaging of forest and gaps, a simple conceptual model is used. This strictly qualitative model has led us to hypothesize that forest radar returns at short wavelengths (eg., C-band) and large incidence angles (e.g., 50 deg) should be most affected by the presence of gaps, whereas returns at long wavelengths and small angles should be least affected. Preliminary analysis of 1989 AIRSAR data from forest near Mt. Shasta supports the hypothesis. Current forest backscatter models such as MIMICS and Santa Barbara Discontinuous Canopy Backscatter Model have in several cases correctly predicted backscatter from forest stands based on inputs of measured or estimated forest parameters. These models do not, however, predict within-stand SAR scene texture, or 'intrinsic scene variability' as Ulaby et al. has referred to it. For instance, the Santa Barbara model, which may be the most spatially coupled of the existing models, is not truly spatial. Tree locations within a simulated pixel are distributed according to a Poisson process, as they are in many natural forests, but tree size is unrelated to location, which is not the case in nature. Furthermore, since pixels of a simulated stand are generated independently in the Santa Barbara model, spatial processes larger than one pixel are not modeled. Using a different approach, Oliver modeled scene texture based on an hypothetical forest geometry. His simulated scenes do not agree well with SAR data, perhaps due to the simple geometric model used. Insofar as texture

  18. Edaphic, salinity, and stand structural trends in chronosequences of native and non-native dominated riparian forests along the Colorado River, USA

    USGS Publications Warehouse

    Merritt, David M.; Shafroth, Patrick B.

    2012-01-01

    Tamarix spp. are introduced shrubs that have become among the most abundant woody plants growing along western North American rivers. We sought to empirically test the long-held belief that Tamarix actively displaces native species through elevating soil salinity via salt exudation. We measured chemical and physical attributes of soils (e.g., salinity, major cations and anions, texture), litter cover and depth, and stand structure along chronosequences dominated by Tamarix and those dominated by native riparian species (Populus or Salix) along the upper and lower Colorado River in Colorado and Arizona/California, USA. We tested four hypotheses: (1) the rate of salt accumulation in soils is faster in Tamarix-dominated stands than stands dominated by native species, (2) the concentration of salts in the soil is higher in mature stands dominated by Tamarix compared to native stands, (3) soil salinity is a function of Tamarix abundance, and (4) available nutrients are more concentrated in native-dominated stands compared to Tamarix-dominated stands. We found that salt concentration increases at a faster rate in Tamarix-dominated stands along the relatively free-flowing upper Colorado but not along the heavily-regulated lower Colorado. Concentrations of ions that are known to be preferentially exuded by Tamarix (e.g., B, Na, and Cl) were higher in Tamarix stands than in native stands. Soil salt concentrations in older Tamarix stands along the upper Colorado were sufficiently high to inhibit germination, establishment, or growth of some native species. On the lower Colorado, salinity was very high in all stands and is likely due to factors associated with floodplain development and the hydrologic effects of river regulation, such as reduced overbank flooding, evaporation of shallow ground water, higher salt concentrations in surface and ground water due to agricultural practices, and higher salt concentrations in fine-textured sediments derived from naturally saline

  19. Description of the stand-damage model: Part of the gypsy moth life system model. Forest Service general technical report (Final)

    SciTech Connect

    Colbert, J.J.; Sheehan, K.A.

    1995-08-16

    This document describes the structure, organization, and mathematical formulations for the Stand-Damage Model and the Biological basis for these formulations. Growth, mortality, and regeneration are modeled along with the effects of user-prescribed defoliation and stand-management actions. The appendices provide a full description of the logic and mathematics in the form of code listings, structure charts, and files.

  20. Longer-term effects of selective thinning on microarthropod communities in a late-successional coniferous forest

    USGS Publications Warehouse

    Peck, R.W.; Niwa, C.G.

    2005-01-01

    Microarthropod densities within late-successional coniferous forests thinned 16-41 yr before sampling were compared with adjacent unthinned stands to identify longer term effects of thinning on this community. Soil and forest floor layers were sampled separately on eight paired sites. Within the forest floor oribatid, mesostigmatid, and to a marginal extent, prostigmatid mites, were reduced in thinned stands compared with unthinned stands. No differences were found for Collembola in the forest floor or for any mite suborder within the soil. Family level examination of mesostigmatid and prostigmatid mites revealed significant differences between stand types for both horizons. At the species level, thinning influenced numerous oribatid mites and Collembola. For oribatid mites, significant or marginally significant differences were found for seven of 15 common species in the forest floor and five of 16 common species in soil. Collembola were affected less, with differences found for one of 11 common species in the forest floor and three of 13 common species in soil. Multivariate analysis of variance and ordination indicated that forest thinning had little influence on the composition of oribatid mite and collembolan communities within either the forest floor or soil. Differences in microclimate or in the accumulation of organic matter on the forest floor were likely most responsible for the observed patterns of abundance. Considering the role that microarthropods play in nutrient cycling, determining the functional response of a wide range of taxa to thinning may be important to effective ecosystem management.

  1. Impacts of Forest Management, Climate, and Productivity on Soil CO2 Efflux from Loblolly Pine (Pinus Taeda L.) Stands Located on the Virginia piedmont and the South Carolina coastal plain

    NASA Astrophysics Data System (ADS)

    Gough, C. M.; Seiler, J. R.; Wiseman, P. E.

    2003-12-01

    Managed loblolly pine (Pinus taeda L.) forests occupy over 13 million hectares or nearly 1.5% of the total land area in the United States. Typically, over 70% of stored carbon (C) in forests resides in soils, emphasizing the need to better understand the impact forest management has on belowground processes affecting C storage. We measured soil CO2 efflux (Ec) from loblolly pine stands located on the Virginia piedmont (VAp) and SC coastal plain (SCcp) in efforts to quantify soil C loss from sites differing in climate, productivity, and common management practices. VAp sites were less productive and subjected to a cooler climate than SCcp sites. VAp sites were burned prior to planting as a form of weed and slash reduction while SCcp sites were bedded to raise planting rows above the water table. Ec was measured monthly for one year in four replicated age classes (1 to >20 years) on both VAp and SCcp sites using a closed dynamic chamber. Spatial variability for a given site was accounted for by taking measurements both near the base of the tree and between rows. Concurrent with Ec measurements, soil temperature (top 10 cm), soil moisture (top 10 cm), stand age, and site index were recorded. Empirical models were developed for the VAp and SCcp sites to assess the relationship between Ec and potential drivers. Soil temperature (top 10 cm) was the major Ec driver on both VAp and SCcp sites, explaining half or more of the variance. Stand age was positively correlated with Ec on VAp sites, but we observed no relationship between stand age and Ec on the SCcp sites. Using the empirical models developed from small chamber measurements, we scaled up soil C losses to the stand level for a 20-year rotation. We estimate a total efflux rate of 278.6 Mg C/ha over a 20-year rotation for SCcp and 210.9 Mg C/ha over the same time period for VAp. The contribution of heterotrophic respiration to Ec was greatest early in the rotation on the SCcp sites, where soils were tilled and

  2. Climate-induced mortality of spruce stands in Belarus

    NASA Astrophysics Data System (ADS)

    Kharuk, Viacheslav I.; Im, Sergei T.; Dvinskaya, Maria L.; Golukov, Alexei S.; Ranson, Kenneth J.

    2015-12-01

    The aim of this work is an analysis of the causes of spruce (Picea abies L.) decline and mortality in Belarus. The analysis was based on forest inventory and Landsat satellite (land cover classification, climate variables (air temperature, precipitation, evaporation, vapor pressure deficit, SPEI drought index)), and GRACE-derived soil moisture estimation (equivalent of water thickness anomalies, EWTA). We found a difference in spatial patterns between dead stands and all stands (i.e., before mortality). Dead stands were located preferentially on relief features with higher water stress risk (i.e., higher elevations, steeper slopes, south and southwestern exposure). Spruce mortality followed a series of repeated droughts between 1990 and 2010. Mortality was negatively correlated with air humidity (r = -0.52), and precipitation (r = -0.57), and positively correlated with the prior year vapor pressure deficit (r = 0.47), and drought increase (r = 0.57). Mortality increased with the increase in occurrence of spring frosts (r = 0.5), and decreased with an increase in winter cloud cover (r = -0.37). Spruce mortality was negatively correlated with snow water accumulation (r = -0.81) and previous year anomalies in water soil content (r = -0.8). Weakened by water stress, spruce stands were attacked by pests and phytopathogens. Overall, spruce mortality in Belarussian forests was caused by drought episodes and drought increase in synergy with pest and phytopathogen attacks. Vast Picea abies mortality in Belarus and adjacent areas of Russia and Eastern Europe is a result of low adaptation of that species to increased drought. This indicates the necessity of spruce replacement by drought-tolerant indigenous (e.g., Pinus sylvestris, Querqus robur) or introduced (e.g., Larix sp. or Pseudotsuga menzieslii) species to obtain sustainable forest growth management.

  3. Take a Stand for Standing

    ERIC Educational Resources Information Center

    Labandz, Stephenie

    2010-01-01

    As a school-based physical therapist, the author sees children with a wide variety of diagnoses affecting their mobility and motor function. Supported standing is an important part of the routines of those who are unable to stand independently due to issues affecting the neuromuscular system. Being eye-to-eye with their peers and interacting with…

  4. 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

  5. Adjacent segment disease.

    PubMed

    Virk, Sohrab S; Niedermeier, Steven; Yu, Elizabeth; Khan, Safdar N

    2014-08-01

    EDUCATIONAL OBJECTIVES As a result of reading this article, physicians should be able to: 1. Understand the forces that predispose adjacent cervical segments to degeneration. 2. Understand the challenges of radiographic evaluation in the diagnosis of cervical and lumbar adjacent segment disease. 3. Describe the changes in biomechanical forces applied to adjacent segments of lumbar vertebrae with fusion. 4. Know the risk factors for adjacent segment disease in spinal fusion. Adjacent segment disease (ASD) is a broad term encompassing many complications of spinal fusion, including listhesis, instability, herniated nucleus pulposus, stenosis, hypertrophic facet arthritis, scoliosis, and vertebral compression fracture. The area of the cervical spine where most fusions occur (C3-C7) is adjacent to a highly mobile upper cervical region, and this contributes to the biomechanical stress put on the adjacent cervical segments postfusion. Studies have shown that after fusion surgery, there is increased load on adjacent segments. Definitive treatment of ASD is a topic of continuing research, but in general, treatment choices are dictated by patient age and degree of debilitation. Investigators have also studied the risk factors associated with spinal fusion that may predispose certain patients to ASD postfusion, and these data are invaluable for properly counseling patients considering spinal fusion surgery. Biomechanical studies have confirmed the added stress on adjacent segments in the cervical and lumbar spine. The diagnosis of cervical ASD is complicated given the imprecise correlation of radiographic and clinical findings. Although radiological and clinical diagnoses do not always correlate, radiographs and clinical examination dictate how a patient with prolonged pain is treated. Options for both cervical and lumbar spine ASD include fusion and/or decompression. Current studies are encouraging regarding the adoption of arthroplasty in spinal surgery, but more long

  6. Estimation of the stand ages of tropical secondary forests after shifting cultivation based on the combination of WorldView-2 and time-series Landsat images

    NASA Astrophysics Data System (ADS)

    Fujiki, Shogoro; Okada, Kei-ichi; Nishio, Shogo; Kitayama, Kanehiro

    2016-09-01

    We developed a new method to estimate stand ages of secondary vegetation in the Bornean montane zone, where local people conduct traditional shifting cultivation and protected areas are surrounded by patches of recovering secondary vegetation of various ages. Identifying stand ages at the landscape level is critical to improve conservation policies. We combined a high-resolution satellite image (WorldView-2) with time-series Landsat images. We extracted stand ages (the time elapsed since the most recent slash and burn) from a change-detection analysis with Landsat time-series images and superimposed the derived stand ages on the segments classified by object-based image analysis using WorldView-2. We regarded stand ages as a response variable, and object-based metrics as independent variables, to develop regression models that explain stand ages. Subsequently, we classified the vegetation of the target area into six age units and one rubber plantation unit (1-3 yr, 3-5 yr, 5-7 yr, 7-30 yr, 30-50 yr, >50 yr and 'rubber plantation') using regression models and linear discriminant analyses. Validation demonstrated an accuracy of 84.3%. Our approach is particularly effective in classifying highly dynamic pioneer vegetation younger than 7 years into 2-yr intervals, suggesting that rapid changes in vegetation canopies can be detected with high accuracy. The combination of a spectral time-series analysis and object-based metrics based on high-resolution imagery enabled the classification of dynamic vegetation under intensive shifting cultivation and yielded an informative land cover map based on stand ages.

  7. View of Stand Pipe (Surge Tank) from FS 502. Looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of Stand Pipe (Surge Tank) from FS 502. Looking northeast - Childs-Irving Hydroelectric Project, Childs System, Stand Pipe (Surge Tank), Forest Service Road 708/502, Camp Verde, Yavapai County, AZ

  8. The impact of beetle-induced conifer death on stand-scale canopy snow interception

    NASA Astrophysics Data System (ADS)

    Pugh, E. T.; Small, E. E.

    2011-12-01

    Snow that falls on a forest either passes through the canopy to the ground or is intercepted by the canopy on needles, branches or bark. The interception of snowfall in forest canopies impacts the water budget because intercepted snow is more likely to sublimate than subcanopy snow. Because forest canopy characteristics are a primary control of canopy snow interception, which in turn controls subcanopy snow accumulation, reductions in canopy density have important implications for snow accumulation on the forest floor. Forest structure can be drastically and rapidly altered by forest disturbance, such as insect attack, wildfire and blowdown. Here, we look at the impact that changing forest characteristics associated with beetle infestation have on canopy snow interception. The mountain pine beetle is currently impacting more than 100,000 km2 of pine forest in western North America. Trees killed by bark beetles eventually lose the majority of their canopy material. We hypothesize that tree death significantly reduces available interception platforms, leading to greater subcanopy snow accumulation than pre-infestation conditions. These potential impacts on snow accumulation are especially important for water resources in the western U.S., where the hydrologic cycle is dominated by snowmelt. We test this hypothesis using extensive data collected from adjacent living and grey phase dead stands. We employ multiple methods to measure canopy snow interception, at both the storm- and season-scales. During the winter of 2011, we made more than 10,000 spatially distributed measurements of subcanopy snow accumulation in three living and two dead lodgepole pine stands as well as three clearings. Measurements were made daily as well as immediately prior to and following storm events, allowing us to calculate storm-scale canopy interception. Interception is estimated by comparing subcanopy snow accumulation in clearings and forests. Additionally, by taking repeated daily

  9. Model-Based Estimation of Forest Canopy Height in Red and Austrian Pine Stands Using Shuttle Radar Topography Mission and Ancillary Data: a Proof-of-Concept Study

    SciTech Connect

    Brown Jr., C G; Sarabandi, K; Pierce, L E

    2007-04-06

    In this paper, accurate tree stand height retrieval is demonstrated using C-band Shuttle Radar Topography Mission (SRTM) height and ancillary data. The tree height retrieval algorithm is based on modeling uniform tree stands with a single layer of randomly oriented vegetation particles. For such scattering media, the scattering phase center height, as measured by SRTM, is a function of tree height, incidence angle, and the extinction coefficient of the medium. The extinction coefficient for uniform tree stands is calculated as a function of tree height and density using allometric equations and a fractal tree model. The accuracy of the proposed algorithm is demonstrated using SRTM and TOPSAR data for 15 red pine and Austrian pine stands (TOPSAR is an airborne interferometric synthetic aperture radar). The algorithm yields root-mean-square (rms) errors of 2.5-3.6 m, which is a substantial improvement over the 6.8-8.3-m rms errors from the raw SRTM minus National Elevation Dataset Heights.

  10. The Development of characteristic Windthrow Pattern in Forests

    NASA Astrophysics Data System (ADS)

    Agster, W.; Ruck, B.

    2003-04-01

    Catastrophic windthrow events in forests result from complex interaction of moving fluid, flexible plant canopy, and mechanical properties of trees and soil. The fundamental mechanisms, involving flow through dynamically responding porous media, tree sway, and gust penetration into canopies, in combination with transition processes at forest edges, require further research. Some studies dealt with model forests, where a few trees per time were linked with measuring equipment to obtain data on bending moments or investigated flow around aeroelastically scaled model forests. The occurence of large bending moments for single trees is not only a function of fetch from a leading edge, but often coincides with windwardly adjacent gaps in the canopy. Such gaps result from forest thinning, but also occur dynamically through gust penetration or failure of single trees. Devastation of complete stands is almost always preceeded by single treefall gaps. It is therefore very important to incorporate initial stages of stand failure in simulations concerning windthrow. For a better understanding of the effects of forest edge parameters, canopy structure and individual tree stability on windthrow, a model forest capable of dynamic response and successive failure has been constructed. First results of wind tunnel experiments on characteristic failure pattern are presented.

  11. Landscape Soil Respiration Fluxes are Related to Leaf Area Index, Stand Height and Density, and Soil Nitrogen in Rocky Mountain Subalpine Forests

    NASA Astrophysics Data System (ADS)

    Berryman, E.; Bradford, J. B.; Hawbaker, T. J.; Birdsey, R.; Ryan, M. G.

    2015-12-01

    There is a recent multi-agency push for accurate assessments of terrestrial carbon stocks and fluxes in the United States. Assessing the state of the carbon cycle in the US requires estimates of stocks and fluxes at large spatial scales. Such assessments are difficult, especially for soil respiration, which dominates ecosystem respiration and is notoriously highly variable over space and time. Here, we report three consecutive years of measurement of soil respiration fluxes in three 1 km2 subalpine forest landscapes: Fraser Experimental Forest (Colorado), Glacier Lakes Ecosystems Experimental Site ("GLEES", Wyoming), and Niwot Ridge (Colorado). Plots were established following the protocol of the US Forest Service's Forest Inventory and Analysis (FIA) Program. Clusters of plots were distributed across the landscape in a 0.25 km grid pattern. From 2004 through 2006, measurements of soil respiration were made once monthly during the growing season and twice during snowpack coverage for each year. Annual cumulative soil respiration was 6.10 (+/- 0.21) Mg ha-1y-1 for Fraser, 6.55 (+/- 0.27) Mg ha-1y-1 for GLEES, and 6.97 (+/- 0.20) Mg ha-1y-1 for Niwot. Variability in annual cumulative soil respiration varied by less than 20% among the three subalpine forests, despite differences in terrain, climate, disturbance history and anthropogenic nitrogen deposition. We quantified the relationship between respiration fluxes and commonly-measured forest properties and found that soil respiration was nonlinearly related to leaf area index, peaking around 2.5 m2m-2 then slowly declining. Annual litterfall (FA) was subtracted from soil respiration (FR) to calculate total belowground carbon flux (TBCF), which declined with increasing tree height, density and soil nitrogen. This landscape analysis of soil respiration confirmed experimentally-derived principles governing carbon fluxes in forests: as trees age and get taller, and in high-fertility areas, carbon flux to roots declines

  12. COMBINING LIDAR ESTIMATES OF BIOMASS AND LANDSAT ESTIMATES OF STAND AGE FOR SPATIALLY EXTENSIVE VALIDATION OF MODELED FOREST PRODUCTIVITY. (R828309)

    EPA Science Inventory

    Extensive estimates of forest productivity are required to understand the
    relationships between shifting land use, changing climate and carbon storage
    and fluxes. Aboveground net primary production of wood (NPPAw) is a major component
    of total NPP and...

  13. Diversity and succession of epiphytic macrolichen communities in low-elevation managed conifer forests in western Oregon

    USGS Publications Warehouse

    Peterson, E.B.; McCune, B.

    2001-01-01

    We examined epiphytic macrolichen communities in Pseudotsuga menziesii (Douglas-fir) forests across the western Oregon landscape for relationships to environmental gradients, stand age and structure, and commercial thinning. We used a retrospective, blocked design through the Coast and the western Cascade ranges of Oregon. Each of our 17 blocks consisted of a young, unthinned stand (age 50-110 yr); an adjacent, thinned stand of equivalent age; and an old-growth stand (age > 200 yr). We found 110 epiphytic macrolichen taxa in the stands. Forage-providing alectorioid lichens and the nitrogen-fixing cyanolichen Lobaria oregana associated strongly with old-growth stands and remnant old trees in younger stands (unthinned + thinned). Relative to unthinned stands, thinned stands had a slightly higher abundance of alectorioid lichens and a greater presence of Hypogymnia imshaugii. However, thinned stands hosted a lower landscape-level (I?) diversity, lacking many species that occurred infrequently in the unthinned stands. Patterns in the lichen community composition correlated strongly with climatic gradients; the greatest variation in composition was between the Coast and Cascade ranges. The difference in communities between mountain ranges was greatest among stands 70-110 yr old, suggesting a difference in lichen successional dynamics between the ranges.

  14. Sources and interpretation of channel complexity in forested subalpine streams of the Southern Rocky Mountains

    NASA Astrophysics Data System (ADS)

    Livers, Bridget; Wohl, Ellen

    2016-05-01

    We evaluate correlations between stream geomorphic complexity and characteristics of the adjacent riparian forest, valley geometry, and land use history in forested subalpine streams of the Colorado Front Range. Measures of geomorphic complexity focus on cross-sectional, planform, and instream wood piece and logjam variables. We categorize adjacent riparian forests as old-growth unmanaged forest (OU), younger unmanaged forest (YU), and younger managed forest (YM), and valley geometry as laterally confined, partly confined, or unconfined. Significant differences in geomorphic stream complexity between OU, YU, and YM result primarily from differences in wood pieces and logjams, and these differences correlate strongly with pool volume and organic matter storage. Significant differences in planform and cross-sectional complexity correlate more strongly with valley geometry, but do not explain as much of the observed variability in complexity between streams as do the wood variables. Unconfined OU streams have the largest wood loads and the greatest complexity, whereas legacy effects of logging, tie-drives, and channel simplification create lower complexity in YM streams, even relative to YU streams flowing through similarly aged forest. We find that management history of riparian forests exerts the strongest control on reduced functional stream channel complexity, regardless of riparian forest stand age.

  15. Actual evapotranspiration estimation in a Mediterranean mountain region by means of Landsat-5 TM and TERRA/AQUA MODIS imagery and Sap Flow measurements in Pinus sylvestris forest stands.

    NASA Astrophysics Data System (ADS)

    Cristóbal, J.; Poyatos, R.; Ninyerola, M.; Pons, X.; Llorens, P.

    2009-04-01

    Evapotranspiration monitoring has important implications on global and regional climate modelling, as well as in the knowledge of the hydrological cycle and in the assessment of environmental stress that affects forest and agricultural ecosystems. An increase of evapotranspiration while precipitation remains constant, or is reduced, could decrease water availability for natural and agricultural systems and human needs. Consequently, water balance methods, as the evapotranspiration modelling, have been widely used to estimate crop and forest water needs, as well as the global change effects. Nowadays, radiometric measurements provided by Remote Sensing and GIS analysis are the technologies used to compute evapotranspiration at regional scales in a feasible way. Currently, the 38% of Catalonia (NE of the Iberian Peninsula) is covered by forests, and one of the most important forest species is Scots Pine (Pinus sylvestris) which represents the 18.4% of the area occupied by forests. The aim of this work is to model actual evapotranspiration in Pinus sylvestris forest stands, in a Mediterranean mountain region, using remote sensing data, and compare it with stand-scale sap flow measurements measured in the Vallcebre research area (42° 12' N, 1° 49' E), in the Eastern Pyrenees. To perform this study a set of 30 cloud-free TERRA-MODIS images and 10 Landsat-5 TM images of path 198 and rows 31 and 32 from June 2003 to January 2005 have been selected to perform evapotranspiration modelling in Pinus sylvestris forest stands. TERRA/AQUA MODIS images have been downloaded by means of the EOS Gateway. We have selected two different types of products which contain the remote sensing data we have used to model daily evapotranspiration, daily LST product and daily calibrated reflectances product. Landsat-5 TM images have been corrected by means of conventional techniques based on first order polynomials taking into account the effect of land surface relief using a Digital

  16. Actual evapotranspiration estimation in a Mediterranean mountain region by means of Landsat-5 TM and TERRA/AQUA MODIS imagery and Sap Flow measurements in Pinus sylvestris forest stands.

    NASA Astrophysics Data System (ADS)

    Cristóbal, J.; Poyatos, R.; Ninyerola, M.; Pons, X.; Llorens, P.

    2009-04-01

    Evapotranspiration monitoring has important implications on global and regional climate modelling, as well as in the knowledge of the hydrological cycle and in the assessment of environmental stress that affects forest and agricultural ecosystems. An increase of evapotranspiration while precipitation remains constant, or is reduced, could decrease water availability for natural and agricultural systems and human needs. Consequently, water balance methods, as the evapotranspiration modelling, have been widely used to estimate crop and forest water needs, as well as the global change effects. Nowadays, radiometric measurements provided by Remote Sensing and GIS analysis are the technologies used to compute evapotranspiration at regional scales in a feasible way. Currently, the 38% of Catalonia (NE of the Iberian Peninsula) is covered by forests, and one of the most important forest species is Scots Pine (Pinus sylvestris) which represents the 18.4% of the area occupied by forests. The aim of this work is to model actual evapotranspiration in Pinus sylvestris forest stands, in a Mediterranean mountain region, using remote sensing data, and compare it with stand-scale sap flow measurements measured in the Vallcebre research area (42° 12' N, 1° 49' E), in the Eastern Pyrenees. To perform this study a set of 30 cloud-free TERRA-MODIS images and 10 Landsat-5 TM images of path 198 and rows 31 and 32 from June 2003 to January 2005 have been selected to perform evapotranspiration modelling in Pinus sylvestris forest stands. TERRA/AQUA MODIS images have been downloaded by means of the EOS Gateway. We have selected two different types of products which contain the remote sensing data we have used to model daily evapotranspiration, daily LST product and daily calibrated reflectances product. Landsat-5 TM images have been corrected by means of conventional techniques based on first order polynomials taking into account the effect of land surface relief using a Digital

  17. Conserving biodiversity in managed forests: Lessons from natural forests

    SciTech Connect

    Hansen, A.J. ); Spies, T.A.; Swanson, F.J.; Ohmann, J.L. )

    1991-06-01

    In this article, the authors review patterns of disturbance and succession in natural forests in the Coastal Northwest and compare structure and composition across an age gradient of unmanaged stands. Stand and landscape patterns in managed forests are then examined and compared with those in natural forests. They draw on the results to offer guidance on the management of Coastal Northwest forests that are dedicated to both wood production and conservation of biodiversity. Finally, the authors suggest that the lessons learned from natural forests here may be useful in other biomes, where unmanaged forests are rare and standards for designing seminatural forests are not available.

  18. Transpiration and water-use efficiency in mixed-species forests versus monocultures: effects of tree size, stand density and season.

    PubMed

    Forrester, David I

    2015-03-01

    Mixtures can be more productive than monocultures and may therefore use more water, which may make them more susceptible to droughts. The species interactions that influence growth, transpiration and water-use efficiency (WUE, tree growth per unit transpiration) within a given mixture vary with intra- and inter-annual climatic variability, stand density and tree size, but these effects remain poorly quantified. These relationships were examined in mixtures and monocultures of Eucalyptus globulus Labill. and Acacia mearnsii de Wildeman. Growth and transpiration were measured between ages 14 and 15 years. All E. globulus trees in mixture that were growing faster than similar sized trees in monocultures had higher WUE, while trees with similar growth rates had similar WUE. By the age of 14 years A. mearnsii trees were beginning to senesce and there were no longer any relationships between tree size and growth or WUE. The relationship between transpiration and tree size did not differ between treatments for either species, so stand-level increases in transpiration simply reflected the larger mean tree size in mixtures. Increasing neighbourhood basal area increased the complementarity effect on E. globulus growth and transpiration. The complementarity effect also varied throughout the year, but this was not related to the climatic seasonality. This study shows that stand-level responses can be the net effect of a much wider range of individual tree-level responses, but at both levels, if growth has not increased for a given species, it appears unlikely that there will be differences in transpiration or WUE for that species. Growth data may provide a useful initial indication of whether mixtures have higher transpiration or WUE, and which species and tree sizes contribute to this effect. PMID:25732385

  19. Edaphic and climatic effects on forest stand development, net primary production, and net ecosystem productivity simulated for Coastal Plain loblolly pine in Virginia

    NASA Astrophysics Data System (ADS)

    Sampson, D. A.; Wynne, R. H.; Seiler, J. R.

    2008-03-01

    We used SECRETS-3PG to simulate net primary production (NPP) and net ecosystem productivity (NEP) of loblolly pine (Pinus taeda L.) growing on the Virginia Coastal Plain, focusing on the effects of soils and climate, and stand age over a 30-year rotation. Soil type was influential, with heavier soils having greater NEP earlier in the rotation than lighter, sandier soils, although these differences disappeared by the rotation end. Climate had only a small effect. Stand age had the largest effect, with simulated annual NEP strongly negative during the first 5 to 8 years of development but peaking at +600 g C m-2 a-1 by age 13. Modest declines in NEP after 13 years were associated with declines in LAI as stands aged. The 30-year mean annual NEP was positive over most of the study area but in a few cases was indistinguishable from zero for northwestern portions of the study. Simulated annual NPP rose from zero to over 2300 g biomass m-2 a-1 by age 12, after which it declined to ˜1700 g biomass m-2 a-1 by rotation end. These results suggest that loblolly pine plantations on the Coastal Plain of Virginia may become net annual C sinks 5 to 9 years after planting but that when averaged over a whole rotation the net carbon accumulation during the baseline rotation simulated here is indistinguishable from zero. Our results also suggest, however, that this finding is sensitive to the length of the rotation, soil type (and thus fertility), and climate, implying that changes in management practices could significantly influence the carbon balance in managed loblolly pine plantations.

  20. Seeing the forest through the trees: comprehensive inference on individual mating patterns in a mixed stand of Quercus robur and Q. petraea

    PubMed Central

    Chybicki, Igor J.; Burczyk, Jaroslaw

    2013-01-01

    Background and Aims Sexual reproduction is one of the most important moments in a life cycle, determining the genetic composition of individual offspring. Controlled pollination experiments often show high variation in the mating system at the individual level, suggesting a persistence of individual variation in natural populations. Individual variation in mating patterns may have significant adaptive implications for a population and for the entire species. Nevertheless, field data rarely address individual differences in mating patterns, focusing rather on averages. This study aimed to quantify individual variation in the different components of mating patterns. Methods Microsatellite data were used from 421 adult trees and 1911 seeds, structured in 72 half-sib families collected in a single mixed stand of Quercus robur and Q. petraea in northern Poland. Using a Bayesian approach, mating patterns were investigated, taking into account pollen dispersal, male fecundity, possible hybridization and heterogeneity in immigrant pollen pools. Key Results Pollen dispersal followed a heavy-tailed distribution (283 m on average). In spite of high pollen mobility, immigrant pollen pools showed strong genetic structuring among mothers. At the individual level, immigrant pollen pools showed highly variable divergence rates, revealing that sources of immigrant pollen can vary greatly among particular trees. Within the stand, the distribution of male fecundity appeared highly skewed, with a small number of dominant males, resulting in a ratio of census to effective density of pollen donors of 5·3. Male fecundity was not correlated with tree diameter but showed strong cline-like spatial variation. This pattern can be attributed to environmental variation. Quercus petraea revealed a greater preference (74 %) towards intraspecific mating than Q. robur (36 %), although mating preferences varied among trees. Conclusions Mating patterns can reveal great variation among individuals

  1. Drought-Caused Forest Decline In The Trans-Baikal Lake Area

    NASA Astrophysics Data System (ADS)

    Ranson, J.; Kharuk, V.; Oscorbin, P.; Im, S.

    2011-12-01

    One of the important consequences of observed and predicted climate change is regional desertification and conversion of forest lands into steppes. We documented progressive forest decline in the trans-Baikal Lake mountains (center point coordinates ~ 51°30'N/116°30'E). This area has a sever continental climate and is a transition area between the Siberian taiga and Mongolian steppes and deserts. Forests are dominated by birch and occupy north-facing mountains slopes (with elevations up to 1200 m). Southern facing slopes are typically covered by grass communities. Analysis of field measurements and satellite temporal data showed an increasing forest decline during the last decades (i.e, 1990-2010). The typical pattern of forest decline was ring-like with the forest die-back starting in the boundary area around the outside of the stand within the forest-grass transition zone. This decline was likely, caused by decreases in precipitation and soil water content. During the last two decades summer precipitation decrease was > 10% (P>0.05), and is now 270 ±30 mm/yr. Similarly, hydrothermal index value decreased to about 12% (P>0.05). Satellite-derived forest decline correlates with precipitation and hydrothermal index decreases. Soil studies showed highest water content values within soils of healthy stands, with minimum values within the dead stand areas, and intermediate within the transition zone. Satellite - based estimates of the total area with drought-caused forest decline was about 106 ha. Along with the observed decline of birch stands, two others climate-caused phenomena were noted within the study and adjacent areas during the last decades: a significant increase of fire frequency and decrease of lake surface area.

  2. Spatial variability of organic layer thickness and carbon stocks in mature boreal forest stands--implications and suggestions for sampling designs.

    PubMed

    Kristensen, Terje; Ohlson, Mikael; Bolstad, Paul; Nagy, Zoltan

    2015-08-01

    Accurate field measurements from inventories across fine spatial scales are critical to improve sampling designs and to increase the precision of forest C cycling modeling. By studying soils undisturbed from active forest management, this paper gives a unique insight in the naturally occurring variability of organic layer C and provides valuable references against which subsequent and future sampling schemes can be evaluated. We found that the organic layer C stocks displayed great short-range variability with spatial autocorrelation distances ranging from 0.86 up to 2.85 m. When spatial autocorrelations are known, we show that a minimum of 20 inventory samples separated by ∼5 m is needed to determine the organic layer C stock with a precision of ±0.5 kg C m(-2). Our data also demonstrates a strong relationship between the organic layer C stock and horizon thickness (R (2) ranging from 0.58 to 0.82). This relationship suggests that relatively inexpensive measurements of horizon thickness can supplement soil C sampling, by reducing the number of soil samples collected, or to enhance the spatial resolution of organic layer C mapping. PMID:26205281

  3. N-15 tracing helps explaining N leaching losses from contrasting forest ecosystems

    NASA Astrophysics Data System (ADS)

    Staelens, J.; Rütting, T.; Huygens, D.; Müller, C.; Verheyen, K.; Boeckx, P.

    2009-04-01

    Despite chronically enhanced nitrogen (N) deposition to forest ecosystems in Europe and NE America, considerable N retention by forests has been observed, reducing N leaching losses. Organic and mineral soil layers typically immobilize more N than the aboveground biomass, but it is unclear which factors determine N retention in forest ecoystems. However, this knowledge is crucial to assess the impact of changing anthropogenic N emissions on future N cycling and N loss of forests. For coniferous and deciduous forest stands at comparable sites, it is known that both N deposition onto the forest floor as well as N loss by leaching below the rooting zone are significantly higher in coniferous stands. In addition, the N loss in coniferous stands is often more enhanced than can be explained by the higher N input only. This suggests lower N retention by coniferous stands, and may be related to differences in litter and soil characteristics, microbial activity, and N uptake by plant roots. To test this hypothesis, we studied the effect of forest type on N retention using 15N tracing techniques: a field tracer experiment and a combination of in situ isotope pool dilution and a tracing model. The N dynamics were examined for two adjacent forest stands (pedunculate oak (Quercus robur L.) and Scots pine (Pinus sylvestris L.)) on a well-drained sandy soil and with a similar stand history, located in a region with high N deposition (Belgium). Input-output N budgets were established by quantifying atmospheric deposition and leaching below the rooting zone, and confirmed the above finding of higher N deposition and disproportionately higher N loss for the pine stand compared to the oak stand. First, the fate of inorganic N within the ecosystems was studied by spraying three pulses of dissolved 15N, either as ammonium or as nitrate, onto the forest floor in 12 plots of 25 m2. The organic and mineral soil layers, tree roots, soil water percolate, ferns, and tree foliage were sampled

  4. Role and Variation of the Amount and Composition of Glomalin in Soil Properties in Farmland and Adjacent Plantations with Reference to a Primary Forest in North-Eastern China

    PubMed Central

    Wang, Qiong; Wang, Wenjie; He, Xingyuan; Zhang, Wentian; Song, Kaishan; Han, Shijie

    2015-01-01

    The glycoprotein known as glomalin-related soil protein (GRSP) is abundantly produced on the hyphae and spores of arbuscular mycorrhizal fungi (AMF) in soil and roots. Few studies have focused on its amount, composition and associations with soil properties and possible land-use influences, although the data hints at soil rehabilitation. By choosing a primary forest soil as a non-degraded reference, it is possible to explore whether afforestation can improve degraded farmland soil by altering GRSP. In this paper, close correlations were found between various soil properties (soil organic carbon, nitrogen, pH, electrical conductivity (EC), and bulk density) and the GRSP amount, between various soil properties and GRSP composition (main functional groups, fluorescent substances, and elements). Afforestation on farmland decreased the EC and bulk density (p < 0.05). The primary forest had a 2.35–2.56-fold higher GRSP amount than those in the plantation forest and farmland, and GRSP composition (tryptophan-like and fulvic acid-like fluorescence; functional groups of C–H, C–O, and O–H; elements of Al, O, Si, C, Ca, and N) in primary forest differed from those in plantation forest and farmland (p < 0.05). However, no evident differences in GRSP amount and composition were observed between the farmland and the plantation forest. Our finding highlights that 30 years poplar afforestation on degraded farmland is not enough to change GRSP-related properties. A longer period of afforestation with close-to-nature managements may favor the AMF-related underground recovery processes. PMID:26430896

  5. Development of understory vegetation in pine and pine-hardwood shelterwood stands in the Ouachita mountains: The first 3 years. Forest Service research paper

    SciTech Connect

    Shelton, M.G.

    1997-09-01

    The shelterwood reproduction cutting method using two overstory compositions (a pine basal area of 30 square feet per acre with and without 15 square feet per acre of hardwoods) and two methods of submerchantable hardwood control (chain-saw felling with and without stump-applied herbicide) was tested in a 2x2 factorial, split-plot design with four randomized complete blocks. Total coverage of understory vegetation after 3 years was greater in the pine overstory treatment (68 percent) than in the pine-hardwood overstory treatment (46 percent) and was slightly greater for manual than chemical hardwood control (60 versus 55 percent). Results indicate that 15 square feet per acre of scattered hardwoods can be retained through at least 3 years after harvest, but additional monitoring will be needed to determine the long-term success of reproduction. Early results suggest that the herbicide treatment was not justified in the stand and site conditions tested in this study; contributing factors were the abundant pine seed production and low levels of competing vegetation.

  6. Predicting plant water content in Eucalyptus grandis forest stands in KwaZulu-Natal, South Africa using field spectra resampled to the Sumbandila Satellite Sensor

    NASA Astrophysics Data System (ADS)

    Oumar, Z.; Mutanga, O.

    2010-06-01

    The measurement of plant water content is essential to assess stress and disturbance in forest plantations. Traditional techniques to assess plant water content are costly, time consuming and spatially restrictive. Remote sensing techniques offer the alternative of a non-destructive and instantaneous method of assessing plant water content over large spatial scales where ground measurements would be impossible on a regular basis. In the context of South Africa, due to the cost and availability of imagery, studies focusing on the estimation of plant water content using remote sensing data have been limited. With the scheduled launch of the South African satellite SumbandilaSat evident in 2009, it is imperative to test the utility of this satellite in estimating plant water content. This study resamples field spectral data measured from a field spectrometer to the band settings of the SumbandilaSat in order to test its potential in estimating plant water content in a Eucalyptus plantation. The resampled SumbandilaSat wavebands were input into a neural network due to its ability to model non-linearity in a dataset and its inherent ability to perform better than conventional linear models. The integrated approach involving neural networks and the resampled field spectral data successfully predicted plant water content with a correlation coefficient of 0.74 and a root mean square error (RMSE) of 1.41% on an independent test dataset outperforming the traditional multiple regression method of estimation. The best-trained neural network algorithm that was chosen for assessing the relationship between plant water content and the SumbandilaSat bands was based on a few points only and more research is required to test the robustness and effectiveness of this sensor in estimating plant water content across different species and seasons. This is critical for monitoring plantation health in South Africa using a cheaply available local sensor containing key vegetation wavelengths.

  7. 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.

  8. Parasitism at the landscape scale: Cowbirds prefer forests

    USGS Publications Warehouse

    Hahn, D.C.; Hatfield, J.S.

    1995-01-01

    Landscape-scale examination of parasitism patterns of Brown-headed Cowbirds (Molothrus ater) revealed heterogeneous parasitism rates across the mosaic of a forest and associated oldfield communities. In a two-year study in Dutchess County, New York, we found a significantly higher parasitism rate in the forest-interior community (n = 301 nests; 17 species) than on the species in the adjacent and nearby old-field and edge (n = 328 nests; 15 species; 32.3% versus 6.5%; p lt 0.0001). Cowbirds invaded a mature 1300-ha forest stand even when their traditional host species were available in adjacent old-field and edge habitats. The forest and old field study areas were located in a 38,000-ha township with 55% forest cover and contained numerous agriculture, dairy, and horse farms that provided favorable habitat for cowbirds, within-forest examination of parasitism patterns revealed four aspects of cowbird parasitism that contrasted with patterns described in other regions; (1) parasitism was concentrated significantly more often on ground and low-nesting (nests ltoreq 1 m) forest species than on medium- and high nesting species (nests gt 1 m; 35. 01 % versus 2993%; p = 0.0393); (2) parasitism was not significantly greater on Neotropical migrant species than on short-distance migrants and residents; (3) the parasitism rate was not higher in nests close to edges; and (4) the parasitism level was low on certain forest species (such as Wood Thrush) that have experienced high parasitism levels in the Midwest. From a management perspective these data suggest that cowbirds exhibit regional differences in host and habitat use; the target host community of a particular cowbird population is unpredictable at the landscape scale; and a landscape scale should be used in designing cowbird studies to accurately assess local population dynamics.

  9. Ecosystem Carbon Stock Influenced by Plantation Practice: Implications for Planting Forests as a Measure of Climate Change Mitigation

    PubMed Central

    Liao, Chengzhang; Luo, Yiqi; Fang, Changming; Li, Bo

    2010-01-01

    Uncertainties remain in the potential of forest plantations to sequestrate carbon (C). We synthesized 86 experimental studies with paired-site design, using a meta-analysis approach, to quantify the differences in ecosystem C pools between plantations and their corresponding adjacent primary and secondary forests (natural forests). Totaled ecosystem C stock in plant and soil pools was 284 Mg C ha−1 in natural forests and decreased by 28% in plantations. In comparison with natural forests, plantations decreased aboveground net primary production, litterfall, and rate of soil respiration by 11, 34, and 32%, respectively. Fine root biomass, soil C concentration, and soil microbial C concentration decreased respectively by 66, 32, and 29% in plantations relative to natural forests. Soil available N, P and K concentrations were lower by 22, 20 and 26%, respectively, in plantations than in natural forests. The general pattern of decreased ecosystem C pools did not change between two different groups in relation to various factors: stand age (<25 years vs. ≥25 years), stand types (broadleaved vs. coniferous and deciduous vs. evergreen), tree species origin (native vs. exotic) of plantations, land-use history (afforestation vs. reforestation) and site preparation for plantations (unburnt vs. burnt), and study regions (tropic vs. temperate). The pattern also held true across geographic regions. Our findings argued against the replacement of natural forests by the plantations as a measure of climate change mitigation. PMID:20523733

  10. Ecosystem carbon stock influenced by plantation practice: implications for planting forests as a measure of climate change mitigation.

    PubMed

    Liao, Chengzhang; Luo, Yiqi; Fang, Changming; Li, Bo

    2010-01-01

    Uncertainties remain in the potential of forest plantations to sequestrate carbon (C). We synthesized 86 experimental studies with paired-site design, using a meta-analysis approach, to quantify the differences in ecosystem C pools between plantations and their corresponding adjacent primary and secondary forests (natural forests). Totaled ecosystem C stock in plant and soil pools was 284 Mg C ha(-1) in natural forests and decreased by 28% in plantations. In comparison with natural forests, plantations decreased aboveground net primary production, litterfall, and rate of soil respiration by 11, 34, and 32%, respectively. Fine root biomass, soil C concentration, and soil microbial C concentration decreased respectively by 66, 32, and 29% in plantations relative to natural forests. Soil available N, P and K concentrations were lower by 22, 20 and 26%, respectively, in plantations than in natural forests. The general pattern of decreased ecosystem C pools did not change between two different groups in relation to various factors: stand age (< 25 years vs. > or = 25 years), stand types (broadleaved vs. coniferous and deciduous vs. evergreen), tree species origin (native vs. exotic) of plantations, land-use history (afforestation vs. reforestation) and site preparation for plantations (unburnt vs. burnt), and study regions (tropic vs. temperate). The pattern also held true across geographic regions. Our findings argued against the replacement of natural forests by the plantations as a measure of climate change mitigation. PMID:20523733

  11. Forest resources of pennsylvania. Forest Service resource bulletin (Final)

    SciTech Connect

    Widmann, R.H.

    1995-06-28

    This report presents an analysis of the results of the 1989 forest inventory of Pennsylvania as well as trends that have occurred since the previous survey. Major topics include changes in forest land by ownership, forest type, and timberland component: stand structure is characterized by stand size, understory wood vegetation, dead trees, and changes in relative stocking; and harvesting by distribution of cut, species composition, and growth to removal ratios.

  12. Forest dynamics

    PubMed Central

    Frelich, Lee

    2016-01-01

    Forest dynamics encompass changes in stand structure, species composition, and species interactions with disturbance and environment over a range of spatial and temporal scales. For convenience, spatial scale is defined as individual tree, neighborhood, stand, and landscape. Whether a given canopy-leveling disturbance will initiate a sequence of development in structure with little change in composition or initiate an episode of succession depends on a match or mismatch, respectively, with traits of the dominant tree species that allow the species to survive disturbance. When these match, certain species-disturbance type combinations lock in a pattern of stand and landscape dynamics that can persist for several generations of trees; thus, dominant tree species regulate, as well as respond to, disturbance. A complex interaction among tree species, neighborhood effects, disturbance type and severity, landform, and soils determines how stands of differing composition form and the mosaic of stands that compose the landscape. Neighborhood effects (e.g., serotinous seed rain, sprouting, shading, leaf-litter chemistry, and leaf-litter physical properties) operate at small spatial extents of the individual tree and its neighbors but play a central role in forest dynamics by contributing to patch formation at stand scales and dynamics of the entire landscape. Dominance by tree species with neutral to negative neighborhood effects leads to unstable landscape dynamics in disturbance-prone regions, wherein most stands are undergoing succession; stability can only occur under very low-severity disturbance regimes. Dominance by species with positive effects leads to stable landscape dynamics wherein only a small proportion of stands undergo succession at any one time. Positive neighborhood effects are common in temperate and boreal zones, whereas negative effects are more common in tropical climates. Landscapes with positive dynamics have alternate categories of dynamics

  13. Forest dynamics.

    PubMed

    Frelich, Lee

    2016-01-01

    Forest dynamics encompass changes in stand structure, species composition, and species interactions with disturbance and environment over a range of spatial and temporal scales. For convenience, spatial scale is defined as individual tree, neighborhood, stand, and landscape. Whether a given canopy-leveling disturbance will initiate a sequence of development in structure with little change in composition or initiate an episode of succession depends on a match or mismatch, respectively, with traits of the dominant tree species that allow the species to survive disturbance. When these match, certain species-disturbance type combinations lock in a pattern of stand and landscape dynamics that can persist for several generations of trees; thus, dominant tree species regulate, as well as respond to, disturbance. A complex interaction among tree species, neighborhood effects, disturbance type and severity, landform, and soils determines how stands of differing composition form and the mosaic of stands that compose the landscape. Neighborhood effects (e.g., serotinous seed rain, sprouting, shading, leaf-litter chemistry, and leaf-litter physical properties) operate at small spatial extents of the individual tree and its neighbors but play a central role in forest dynamics by contributing to patch formation at stand scales and dynamics of the entire landscape. Dominance by tree species with neutral to negative neighborhood effects leads to unstable landscape dynamics in disturbance-prone regions, wherein most stands are undergoing succession; stability can only occur under very low-severity disturbance regimes. Dominance by species with positive effects leads to stable landscape dynamics wherein only a small proportion of stands undergo succession at any one time. Positive neighborhood effects are common in temperate and boreal zones, whereas negative effects are more common in tropical climates. Landscapes with positive dynamics have alternate categories of dynamics

  14. Spatial and Temporal Variation in Feather Moss Associated Nitrogen Fixation in Coniferous and Deciduous Dominated Alaskan Boreal Forests

    NASA Astrophysics Data System (ADS)

    Jean, M.; Mack, M. C.; Johnstone, J. F.

    2015-12-01

    Dominant canopy tree species have strong effects on the composition and function of understory species. In boreal forests, forest floor bryophytes and their associated microbes are a primary source of ecosystem nitrogen (N) inputs, and thus an important process regulating ecosystem productivity. Bryophyte composition and abundance varies with forest composition, yet how such changes can affect ecosystem processes such as N fixation is still poorly understood. Our goal is to investigate how cyanobacteria-based N fixation occurring in the two most common feather mosses in the Alaskan boreal forest (Pleurozium schreberi and Hylocomium splendens) varies among coniferous and deciduous forest types, over the growing season, and across a nutrient availability gradient. Twelve patches of H. splendens and P. schreberi were identified in three pairs (blocks) of adjacent stands of paper birch (Betula neoalaskana) and black spruce (Picea mariana) near Fairbanks, interior Alaska. Sampling occurred in one block in June, July, August, and September 2014, and in the three blocks once in August 2014. Moss leaf area, moisture and weight, as well as environmental variables such as air temperature and canopy cover were recorded. Fixation rates were consistently higher for P. schreberi than for H. splendens. Overall, N fixation rates were lower in birch than in spruce stands and peaked in August, or July for P. schreberi in birch stands. Moreover, fixation rates varied along the nutrient availability gradient, with fixation rates higher where nutrient availability was lower. This difference was especially clear in spruce stands. Our preliminary results suggest that moss species, canopy type, and environmental factors all influence N fixation rates in Alaskan boreal forests. Our results will enhance the knowledge of the processes that drive N fixation in boreal forests, which is important for predicting ecosystem consequences of changing forest composition.

  15. Atmospheric inputs and nitrogen saturation status in and adjacent to Class I wilderness areas of the northeastern US.

    PubMed

    Templer, Pamela H; Weathers, Kathleen C; Lindsey, Amanda; Lenoir, Katherine; Scott, Lindsay

    2015-01-01

    Atmospheric inputs of N and S in bulk deposition (open collectors) and throughfall (beneath canopy collectors) were measured in and adjacent to two Class 1 wilderness areas of the northeastern US. In general, atmospheric S inputs followed our expectations with throughfall S fluxes increasing with elevation in the White Mountains, New Hampshire and throughfall S fluxes being greater in coniferous than deciduous stands in both sites. In contrast, throughfall N fluxes decreased significantly with elevation. Throughfall NO3 (-) fluxes were greater in coniferous than deciduous stands of Lye Brook, Vermont, but were greater in deciduous than coniferous stands of the White Mountains. We found overlap in the range of values for atmospheric N inputs between our measurements and monitoring data [National Atmospheric Deposition Program (NADP) and Clean Air Status and Trends Network (CASTNET)] for wet and total (wet + dry) deposition at Lye Brook. However, our measurements of total S deposition in the White Mountains and bulk (wet) deposition at both Lye Brook and the White Mountains were significantly lower than NADP plus CASTNET, and NADP data, respectively. Natural abundance (18)O in throughfall and bulk deposition were not significantly different, suggesting that there was no significant biological production of [Formula: see text] via nitrification in the canopy. NO3 (-) concentrations in streams were low and had natural abundance (18)O values consistent with microbial production, demonstrating that atmospheric N is being biologically transformed while moving through these watersheds and that these forested watersheds are unlikely to be N saturated. PMID:25407620

  16. Quantifying forest vertical structure to determine bird habitat quality in the Greenbelt Corridor, Denton, TX

    NASA Astrophysics Data System (ADS)

    Matsubayashi, Shiho

    This study presents the integration of light detection and range (LiDAR) and hyperspectral remote sensing to create a three-dimensional bird habitat map in the Greenbelt Corridor of the Elm Fork of the Trinity River. This map permits to examine the relationship between forest stand structure, landscape heterogeneity, and bird community composition. A biannual bird census was conducted at this site during the breeding seasons of 2009 and 2010. Census data combined with the three-dimensional map suggest that local breeding bird abundance, community structure, and spatial distribution patterns are highly influenced by vertical heterogeneity of vegetation surface. For local breeding birds, vertical heterogeneity of canopy surface within stands, connectivity to adjacent forest patches, largest forest patch index, and habitat (vegetation) types proved to be the most influential factors to determine bird community assemblages. Results also highlight the critical role of secondary forests to increase functional connectivity of forest patches. Overall, three-dimensional habitat descriptions derived from integrated LiDAR and hyperspectral data serve as a powerful bird conservation tool that shows how the distribution of bird species relates to forest composition and structure at various scales.

  17. B-1 Test Stand

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The B-1 test stand, the largest of three test stands used for Space Shuttle Main Engine testing at Stennis Space Center, is a dual position engine stand that was modified for single-engine tests. This structure stands 295 feet tall or 407 feet tall with the crane fully extended.

  18. 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

  19. Impact of road network on the structure of a multifunctional forest landscape unit in southern Turkey.

    PubMed

    Eker, Mehmet; Coban, Huseyin Oguz

    2010-01-01

    Forest roads have many kinds of direct and indirect effects such as physical, ecological, and socio-economic effects in landscape scale. In this study the relationship between forest road network and the structure of a multifunctionally planned forest landscape, in the south of Turkey was examined. The aim of the study was to determine whether or not the correlation between road network and landscape structure across a gradient of road density categorical road/no road approach and landscape pattern data from the managed forest landscapes existed. It was concerned with three type polygons that were forest functioning patches, compartments, and stand patches and were associated with higher road density or existing of road network. To quantify the case, it was analyzed whether the spatial structure of forest patches adjacent to roads differs from the spatial structure of forest patches away from roads. GIS was used to integrate quantitative indices of landscape structure. There was little negatively significant relationship between road density and patch area/size, patch perimeter and shape index of patton index (PI) and no correlation with patch number and Fractal Dimension (FD). The forest road network modified spatial pattern of patch shape through PI values. The road network increased the number of patch and decreased mean patch size. The existence of road network was more effective than topography index appearing of PI and FD in the roaded areas. It was indicated to potential reverse impacts of road network on spatial structure of forest compartments in terms of shape index (FD). Highest proportions of harvestable forest areas fall into roaded areas. The results define that road networks are effective on the spatial structure of forest landscape. The forest road network of study area has all probable ecological impacts of forest roads mentioned in context. PMID:20648828

  20. Spatial and temporal variability of soil CO2 efflux in southeastern forests

    NASA Astrophysics Data System (ADS)

    Oishi, A. C.; Palmroth, S.; Butnor, J. R.; Johnsen, K.; Oren, R.

    2011-12-01

    The combination of biotic and abiotic factors that contribute to soil CO2 efflux can lead to large variability across spatial and temporal scales. This variability can result in uncertainty in respiration estimates; however, it can also provide insight into the primary processes affecting CO2 emissions from soil. In order to quantify the magnitude and identify the sources of variability in soil CO2 efflux across spatial and temporal scales, we deployed several automated, multi-chamber sampling systems in forest stands in the southeastern U.S. We measured fluxes from a medium-age loblolly pine stand for 10 years (2001-2010), which spanned two severe droughts and one very wet year. During this time period, we also operated three systems in additional plots within the pine stand for 5 years, one system in an adjacent mixed-species broadleaf deciduous stand for 4 years, and one system in a nearby mature loblolly pine stand for 2 years. The high frequency of measurements (~2 hours per chamber) allows us to examine diurnal trends and precipitation responses while longevity of this study provides information on interannual variability and effects of stand age. Additionally, we quantify spatial variability at the scale of plot-level (1-10 m), stand-level (~100 m), and regionally (1-50 km) to examine the effects of local heterogeneity, species composition, and soil type. Chamber-based measurements are compared with leaf litter fall, trenched plot data, and eddy covariance measurements.

  1. Post-disturbance plant community dynamics following a rare natural-origin fire in a Tsuga canadensis forest.

    PubMed

    Murray, Bryan D; Holmes, Stacie A; Webster, Christopher R; Witt, Jill C

    2012-01-01

    Opportunities to directly study infrequent forest disturbance events often lead to valuable information about vegetation dynamics. In mesic temperate forests of North America, stand-replacing crown fire occurs infrequently, with a return interval of 2000-3000 years. Rare chance events, however, may have profound impacts on the developmental trajectories of forest ecosystems. For example, it has been postulated that stand-replacing fire may have been an important factor in the establishment of eastern hemlock (Tsuga canadensis) stands in the northern Great Lakes region. Nevertheless, experimental evidence linking hemlock regeneration to non-anthropogenic fire is limited. To clarify this potential relationship, we monitored vegetation dynamics following a rare lightning-origin crown fire in a Wisconsin hemlock-hardwood forest. We also studied vegetation in bulldozer-created fire breaks and adjacent undisturbed forest. Our results indicate that hemlock establishment was rare in the burned area but moderately common in the scarified bulldozer lines compared to the reference area. Early-successional, non-arboreal species including Rubus spp., Vaccinium angustifolium, sedges (Carex spp.), grasses, Epilobium ciliatum, and Pteridium aquilinium were the most abundant post-fire species. Collectively, our results suggest that competing vegetation and moisture stress resulting from drought may reduce the efficacy of scarification treatments as well as the usefulness of fire for preparing a suitable seedbed for hemlock. The increasing prevalence of growing-season drought suggests that silvicultural strategies based on historic disturbance regimes may need to be reevaluated for mesic species. PMID:22928044

  2. Post-Disturbance Plant Community Dynamics following a Rare Natural-Origin Fire in a Tsuga canadensis Forest

    PubMed Central

    Murray, Bryan D.; Holmes, Stacie A.; Webster, Christopher R.; Witt, Jill C.

    2012-01-01

    Opportunities to directly study infrequent forest disturbance events often lead to valuable information about vegetation dynamics. In mesic temperate forests of North America, stand-replacing crown fire occurs infrequently, with a return interval of 2000–3000 years. Rare chance events, however, may have profound impacts on the developmental trajectories of forest ecosystems. For example, it has been postulated that stand-replacing fire may have been an important factor in the establishment of eastern hemlock (Tsuga canadensis) stands in the northern Great Lakes region. Nevertheless, experimental evidence linking hemlock regeneration to non-anthropogenic fire is limited. To clarify this potential relationship, we monitored vegetation dynamics following a rare lightning-origin crown fire in a Wisconsin hemlock-hardwood forest. We also studied vegetation in bulldozer-created fire breaks and adjacent undisturbed forest. Our results indicate that hemlock establishment was rare in the burned area but moderately common in the scarified bulldozer lines compared to the reference area. Early-successional, non-arboreal species including Rubus spp., Vaccinium angustifolium, sedges (Carex spp.), grasses, Epilobium ciliatum, and Pteridium aquilinium were the most abundant post-fire species. Collectively, our results suggest that competing vegetation and moisture stress resulting from drought may reduce the efficacy of scarification treatments as well as the usefulness of fire for preparing a suitable seedbed for hemlock. The increasing prevalence of growing-season drought suggests that silvicultural strategies based on historic disturbance regimes may need to be reevaluated for mesic species. PMID:22928044

  3. Standing Tall: The Benefits of Standing Devices

    ERIC Educational Resources Information Center

    Warner, Mark P.

    2007-01-01

    In the author's opinion as a pediatric physical therapist, with the exception of a wheelchair, there is no other piece of assistive technology that is more beneficial to children and adults with special needs than a standing device. Postural symmetry during standing and walking activities is extremely important for everyone. Very few children…

  4. Birch Stands Growth Increase in Western Siberia

    NASA Technical Reports Server (NTRS)

    Kharuk, Viacheslav I.; Kuzmichev, Valeriy V.; Im, Sergey T.; Ranson, Kenneth J.

    2014-01-01

    Birch (Betula pendula Roth) growth within the Western Siberia forest-steppe was analyzed based on long-term (1897-2006) inventory data (height, diameter at breast height [dbh], and stand volume). Analysis of biometry parameters showed increased growth at the beginning of twenty-first century compared to similar stands (stands age = 40-60 years) at the end of nineteenth century. Mean height, dbh, and stem volume increased from 14 to 20 m, from 16 to 22 cm, and from approx. 63 to approx. 220 cu m/ha, respectively. Significant correlations were found between the stands mean height, dbh, and volume on the one hand, and vegetation period length (r(sub s) = 0.71 to 0.74), atmospheric CO2 concentration (r(sub s) = 0.71 to 0.76), and drought index (Standardized Precipitation-Evapotranspiration Index, r(sub s) = -0.33 to -0.51) on the other hand. The results obtained have revealed apparent climate-induced impacts (e.g. increase of vegetation period length and birch habitat drying due to drought increase) on the stands growth. Along with this, a high correlation of birch biometric parameters and [CO2] in ambient air indicated an effect of CO2 fertilization. Meanwhile, further drought increase may switch birch stand growth into decline and greater mortality as has already been observed within the Trans-Baikal forest-steppe ecotone.

  5. Managed forest reserves: preserving diversity

    USGS Publications Warehouse

    Tappeiner, John; Poage, Nathan; Erickson, Janet L.

    2003-01-01

    Background As part of the Northwest Forest Plan, large areas have been designated on many federal forests in western Oregon to provide critical habitat for plants and animals that are associated with old-growth habitat. Some of the structural characteristics often considered typical of old forests include large-diameter overstory trees, large standing and fallen dead trees, and one or more understory layers (Figure 1). However, not all of these areas are currently in old-growth conditions. Many of them contain young (<40 years), uniformly dense Douglas-fir stands that regenerated after timber harvest. The original management goal for these stands was to produce high yields of timber and associated wood products. With implementation of the Northwest Forest Plan in 1994, the management objective shifted to accelerating development of old-growth characteristics by enhancing structural and biological diversity of these areas. A major challenge today is how to promote these structural characteristics in younger stands. Researchers have been asking if lessons can be learned from the development of our current old growth and applied to management of younger stands. Dr. John Tappeiner and his university and agency research partners are helping to answer this question by examining the differences in development between old-growth and young stands in western Oregon. Understanding how the structure of these old forests developed may provide a model for management of young stands, especially when the management goal is to provide habitat for species associated with older forests.

  6. Integration of airborne LiDAR data and voxel-based ray tracing to determine high-resolution solar radiation dynamics at the forest floor: implications for improving stand-scale distributed snowmelt models

    NASA Astrophysics Data System (ADS)

    Musselman, K. N.; Molotch, N. P.; Margulis, S. A.

    2012-12-01

    Forest architecture dictates sub-canopy solar irradiance and the resulting patterns can vary seasonally and over short spatial distances. These radiation dynamics are thought to have significant implications on snowmelt processes, regional hydrology, and remote sensing signatures. The variability calls into question many assumptions inherent in traditional canopy models (e.g. Beer's Law) when applied at high resolution (i.e. 1 m). We present a method of estimating solar canopy transmissivity using airborne LiDAR data. The canopy structure is represented in 3-D voxel space (i.e. a cubic discretization of a 3-D domain analogous to a pixel representation of a 2-D space). The solar direct beam canopy transmissivity (DBT) is estimated with a ray-tracing algorithm and the diffuse component is estimated from LiDAR-derived effective LAI. Results from one year at five-minute temporal and 1 m spatial resolutions are presented from Sequoia National Park. Compared to estimates from 28 hemispherical photos, the ray-tracing model estimated daily mean DBT with a 10% average error, while the errors from a Beer's-type DBT estimate exceeded 20%. Compared to the ray-tracing estimates, the Beer's-type transmissivity method was unable to resolve complex spatial patterns resulting from canopy gaps, individual tree canopies and boles, and steep variable terrain. The snowmelt model SNOWPACK was applied at locations of ultrasonic snow depth sensors. Two scenarios were tested; 1) a nominal case where canopy model parameters were obtained from hemispherical photographs, and 2) an explicit scenario where the model was modified to accept LiDAR-derived time-variant DBT. The bulk canopy treatment was generally unable to simulate the sub-canopy snowmelt dynamics observed at the depth sensor locations. The explicit treatment reduced error in the snow disappearance date by one week and both positive and negative melt-season SWE biases were reduced. The results highlight the utility of LiDAR canopy

  7. Structural and compositional controls on transpiration in 40- and 450-year-old riparian forests in western Oregon, USA.

    PubMed

    Moore, Georgianne W; Bond, Barbara J; Jones, Julia A; Phillips, Nathan; Meinzer, Federick C

    2004-05-01

    Large areas of forests in the Pacific Northwest are being transformed to younger forests, yet little is known about the impact this may have on hydrological cycles. Previous work suggests that old trees use less water per unit leaf area or sapwood area than young mature trees of the same species in similar environments. Do old forests, therefore, use less water than young mature forests in similar environments, or are there other structural or compositional components in the forests that compensate for tree-level differences? We investigated the impacts of tree age, species composition and sapwood basal area on stand-level transpiration in adjacent watersheds at the H.J. Andrews Forest in the western Cascades of Oregon, one containing a young, mature (about 40 years since disturbance) conifer forest and the other an old growth (about 450 years since disturbance) forest. Sap flow measurements were used to evaluate the degree to which differences in age and species composition affect water use. Stand sapwood basal area was evaluated based on a vegetation survey for species, basal area and sapwood basal area in the riparian area of two watersheds. A simple scaling exercise derived from estimated differences in water use as a result of differences in age, species composition and stand sapwood area was used to estimate transpiration from late June through October within the entire riparian area of these watersheds. Transpiration was higher in the young stand because of greater sap flux density (sap flow per unit sapwood area) by age class and species, and greater total stand sapwood area. During the measurement period, mean daily sap flux density was 2.30 times higher in young compared with old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees. Sap flux density was 1.41 times higher in young red alder (Alnus rubra Bong.) compared with young P. menziesii trees, and was 1.45 times higher in old P. menziesii compared with old western hemlock (Tsuga heterophylla (Raf

  8. An appraisal of the fitness consequences of forest disturbance for wildlife using habitat selection theory.

    PubMed

    Hodson, James; Fortin, Daniel; Leblanc, Mélanie-Louise; Bélanger, Louis

    2010-09-01

    Isodar theory can help to unveil the fitness consequences of habitat disturbance for wildlife through an evaluation of adaptive habitat selection using patterns of animal abundance in adjacent habitats. By incorporating measures of disturbance intensity or variations in resource availability into fitness-density functions, we can evaluate the functional form of isodars expected under different disturbance-fitness relationships. Using this framework, we investigated how a gradient of forest harvesting disturbance and differences in resource availability influenced habitat quality for snowshoe hares (Lepus americanus) and red-backed voles (Myodes gapperi) using pairs of logged and uncut boreal forest. Isodars for both species had positive intercepts, indicating reductions to maximum potential fitness in logged stands. Habitat selection by hares depended on both conspecific density and differences in canopy cover between harvested and uncut stands. Fitness-density curves for hares in logged stands were predicted to shift from diverging to converging with those in uncut forest across a gradient of high to low disturbance intensity. Selection for uncut forests thus became less pronounced with increasing population size at low levels of logging disturbance. Voles responded to differences in moss cover between habitats which reflected moisture availability. Lower moss cover in harvested stands either reduced maximum potential fitness or increased the relative rate of decline in fitness with density. Differences in vole densities between harvested and uncut stands were predicted, however, to diminish as populations increased. Our findings underscore the importance of accounting for density-dependent behaviors when evaluating how changing habitat conditions influence animal distribution. PMID:20658153

  9. Nitrogen fertilization impacts on C sequestration in Pacific Northwest Forests.

    NASA Astrophysics Data System (ADS)

    Harrison, R.; Briggs, D.; Gonyea, R.; Collier, R.; Adams, A.

    2006-05-01

    We examined whether N fertilization of Douglas-fir (Psuedotsuga menziesii [Mirb.]) plantations in western Washington and Oregon State could affect C sequestration in trees. Nine unthinned and six thinned sites, which received 1000 kg N ha-1 over a 16-y period, were compared with adjacent unfertilized control sites. Carbon contained in the live trees was estimated using biomass equations and average carbon concentrations. There was more C estimated to be stored in live trees of the fertilized vs. control plots. On average, fertilized trees contained 10.5 percent more C (average 24 Mg/ha) than the control plots in the unthinned and 22.5 percent more C (average 38 Mg/ha) than the control plots for the live trees in the thinned stands. In a smaller study of three stands, an additional 8.0 Mg C/ha accumulated in the soil and other non-live-tree stand components. This study suggests that N fertilization of commercial forests in western Washington could substantially increase C stored in these forest ecosystems. Considering that there are approximately 20.9 million hectares of forest land in the states of Washington and Oregon, fertilization could result in an additional 0.82 Pg of additional carbon sequestrated during a single rotation of forestland, a period of approximately 40 years, for an average of 0.02 Pg/year. How much of this C would offset fossil fuel use in the long-term is unclear, but it is smaller than this total. Keywords: Forest Fertilization, Urea, Carbon sequestration, Douglas-fir

  10. Effect of prior disturbances on the extent and severity of wildfire in Colorado subalpine forests.

    PubMed

    Kulakowski, Dominik; Veblen, Thomas T

    2007-03-01

    Disturbances are important in creating spatial heterogeneity of vegetation patterns that in turn may affect the spread and severity of subsequent disturbances. Between 1997 and 2002 extensive areas of subalpine forests in northwestern Colorado were affected by a blowdown of trees, bark beetle outbreaks, and salvage logging. Some of these stands were also affected by severe fires in the late 19th century. During a severe drought in 2002, fires affected extensive areas of these subalpine forests. We evaluated and modeled the extent and severity of the 2002 fires in relation to these disturbances that occurred over the five years prior to the fires and in relation to late 19th century stand-replacing fires. Occurrence of disturbances prior to 2002 was reconstructed using a combination of tree-ring methods, aerial photograph interpretation, field surveys, and geographic information systems (GIS). The extent and severity of the 2002 fires were based on the normalized difference burn ratio (NDBR) derived from satellite imagery. GIS and classification trees were used to analyze the effects of prefire conditions on the 2002 fires. Previous disturbance history had a significant influence on the severity of the 2002 fires. Stands that were severely blown down (> 66% trees down) in 1997 burned more severely than other stands, and young (approximately 120 year old) postfire stands burned less severely than older stands. In contrast, prefire disturbances were poor predictors of fire extent, except that young (approximately 120 years old) postfire stands were less extensively burned than older stands. Salvage logging and bark beetle outbreaks that followed the 1997 blowdown (within the blowdown as well as in adjacent forest that was not blown down) did not appear to affect fire extent or severity. Conclusions regarding the influence of the beetle outbreaks on fire extent and severity are limited, however, by spatial and temporal limitations associated with aerial detection

  11. Study on the Explainable Ability by Using Airborne LIDAR in Stand Value and Stand Competition

    NASA Astrophysics Data System (ADS)

    Huang, S. C.; Yeh, J. Y.; Chen, C. T.; Chen, J. C.

    2016-06-01

    Forest canopy structure is composed by the various species. Sun light is a main factor to affect the crown structures after tree competition. However, thinning operation is an appropriate way to control canopy density, which can adjust the competition conditions in the different crown structures. Recently, Airborne Light Detection and Ranging (LiDAR), has been established as a standard technology for high precision three dimensional forest data acquisition; it could get stand characteristics with three-dimensional information that had develop potential for the structure characteristics of forest canopy. The 65 years old, different planting density of Cryptomeria japonica experiment area was selected for this study in Nanytou, Taiwan. Use the LiDAR image to estimate LiDAR characteristic values by constructed CHM, voxel-based LiDAR, mu0ltiple echoes, and assess the accuracy of stand characteristics with intensity values and field data. The competition index was calculated with field data, and estimate competition index of LiDAR via multiple linear regression. The results showed that the highest accuracy with stand characteristics was stand high which estimate by LiDAR, its average accuracy of 91.03%. LiDAR raster grid size was 20 m × 20 m for the correlation was the best, however, the higher canopy density will reduce the accuracy of the LiDAR characteristic values to estimate the stand characteristics. The significantly affect canopy thickness and the degree of competition in different planting distances.

  12. Relationships between multipolarized radar backscatter and slash pine stand parameters

    NASA Technical Reports Server (NTRS)

    Hussin, Yousif Ali; Hoffer, Roger M.

    1989-01-01

    Multipolarized L-band (24.5 cm) aircraft radar data was obtained for a primarily forested area in northern Florida. Based on the results of previous studies by Hoffer and Hussin (1989), a swath of medium incidence angle (35-25 deg) data was defined. Three groups of slash pine stands were located in the data: 4- to 17-year-old plantations, 18- to 48-year-old plantations, and 16- to 53-year-old natural stands. Stand data obtained from the forest-products companies operating in the area include age, tree height, diameter-at-breast height, basal area, volume (cords/acre), and density (trees/acre). Each of these stand parameters were compared to each of the four polarizations (HH, VV, VH, and HV) of the radar data for each group of stands. Statistically significant relationships were found between the radar backscatter and the forest stand parameters only for the 4- to 17-year-old slash pine plantation stands. In general, the cross-polarized radar backscatter was more highly correlated with the various stand parameters than the like-polarized backscatter, and the VV-polarized data were more highly correlated than the HH-polarized data.

  13. PATTERNS OF NITRATE LOSSES FROM FORESTED BASINS IN THE OREGON COAST RANGE

    EPA Science Inventory

    Numerous factors may control losses of dissolved nutrients from forested basins in the Oregon Coast Range. Potentially important factors include forest composition, stand age, forest management, grazing, agriculture, sewage inputs and bedrock types, as well as others perhaps not...

  14. The biogeochemistry of grassland to forest conversion: a tale of protons, cations, and water in the Pampas

    NASA Astrophysics Data System (ADS)

    Jobbagy, E. G.; Jackson, R. B.

    2001-12-01

    Vegetation, through its cycling and sequestration of materials, can exert a strong influence on soil chemistry. We used tree plantation and native grasslands in the Pampas in South America as a model system to explore this influence. Most ecosystems and soils in the Pampas developed throughout the Quaternary under the complete absence of trees until the arrival of Europeans when trees were introduced. We evaluate the effect of grassland to forest shift on H+, base cations, Cl, and Mn pools using Eucalyptus plantations (10 to 100 years of age) paired with adjacent stands of native grassland. Across all sites, soil pH dropped significantly after afforestation (8 paired sites, p<0.01, mean pH forests = 4.2, mean pH grasslands = 5.4). A complete base cation and proton balance for three paired sites revealed a maximum acidification at intermediate soil depths (10-50 cm) associated with Ca redistribution by trees. Soil proton gains after 50 years (4-6 mol+/m2) were balanced by Ca sequestration in tree biomass and forest floor suggesting that higher Ca cycling by trees compared to grasses may be the mechanism of acidification. The same soil profiles showed alkalinization and large net Na gains below 50 cm of depth (>500 g/m2 in 50-100 cm) after afforestation. Based on precipitation, throughfall, litterfall, soil, and groundwater elemental composition we identified groundwater as the most likely source of Na inputs to the soil. In contrast with grasses, tree roots reached and used groundwater. During periods of high atmospheric water demand we observed diurnal fluctuations of water table level under a forest stand but not under its adjacent grassland stand. On average ground water was 1 m deeper and 10 times more saline in the forest stand compared to the adjacent grassland 200 m away (mean EC forest = 12993 uS, mean EC grassland = 819 uS for grassland). These observations point to water use and groundwater salt concentration by trees as an important step in deep soil

  15. Summer lowflow deficits after two decades of forest regeneration in the western Cascades, Oregon

    NASA Astrophysics Data System (ADS)

    Perry, T.; Jones, J. A.

    2008-12-01

    This study explored the long-term response of summer water yields to past forest management practices, specifically the conversion of mature and old growth conifer forests to young forest plantations, in seasonally drought-stressed conifer forests of western Oregon. Results were based on long-term (40 to 50-year) paired watershed experiments in the HJ Andrews Forest in the Willamette National Forest and Coyote Creek in the South Umpqua National Forest. In the third decade after 100 percent clearcutting, streamflows were 30 to 80 percent lower in the young forest than the reference (mature and old forest) watershed during August to November. In the third decade after patch-clearcutting, summer streamflows were 20 to 40 percent lower in the cut watershed compared to the control. In the third decade after a 50 percent overstory thin, almost all summer low flows were within 25 percent of the flows at the control watershed. A 12 percent understory thin in a clearcut watershed during the third decade led to a temporary, minor abatement in summer low flow declines, but within five years, summer low flows from the thinned watershed were similar to those from an adjacent, unthinned forest plantation of similar age. Streamflow deficits emerged as early as March or April and persisted into October and November in the warmer, drier site in southern Oregon (Coyote Creek), whereas summer streamflow deficits emerged later and persisted for fewer weeks in the cooler, wetter Andrews Forest. These findings are consistent with previous studies demonstrating (1) increases in water use in certain conifer species relative to others (e.g. Douglas-fir versus pine); (2) higher water use in young (i.e., 10 to 50- yr-old) compared to old (100 to 250-yr-old) stands of many tree species; and (3) decreased interception capacity of young relative to old forest stands associated with loss of canopy epiphytes. Results appear to be robust, despite gaps in data availability, uncertainties associated

  16. Planter unit test stand

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A planter test stand was developed to evaluate individual row-crop metering units in early 2013. This test stand provided the ability to quantify actual seed metering in terms of population, seed spacing, skips, and multiples over a range of meter RPMs and vacuum pressures. Preliminary data has been...

  17. Test Stand 500

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This is a ground level view of Test Stand 500 at the east test area of the Marshall Space Flight Center. Originally constructed in 1966, Test Stand 500 is a multipurpose, dual-position test facility. The stand was utilized to test liquid hydrogen/liquid oxygen turbopumps and combustion devices for the J-2 engine. One test position has a high superstructure with lines and tankage for testing liquid hydrogen and liquid oxygen turbopumps while the other position is adaptable to pressure-fed test programs such as turbo machinery bearings or seals. The facility was modified in 1980 to support Space Shuttle main engine (SSME) bearing testing.

  18. Clear-Cut Stand Size and Scrub-Successional Bird Assemblages

    SciTech Connect

    Krementz,D.G.; Christie, J.S.

    1999-03-08

    We investigated the effects of clear-cut size on species richness, reproductive effort, and relative abundance of scrub-scrub birds at the Savannah River Site. Stands varied in size from 2 to 57 ha that were 2 to 6 years old. Species richness was not explained by stand size or stand age. In regressing stand size on bird species richness, we found a significant negative relationship for the bird community. Frequency of capture was unrelated to stand size. Clear-cut stand size does not appear to be an important variable in forest management with respect to the bird community.

  19. Soil Collembola communities within Plešné Lake and Čertovo Lake catchments, the Bohemian Forest

    NASA Astrophysics Data System (ADS)

    Čuchta, Peter

    2016-04-01

    The soil Collembola communities were studied for three years in disturbed spruce forest stands in the catchments areas of Čertovo and Plešné Lakes in the Bohemian Forest, Czech Republic. The study was focused on the impact of the windthrow, bark beetle outbreak damage and consecutive changes in the forest stands including soil environment. Four different treatments were selected for the study on both study areas: undamaged (control) forest stands, "dead" forest stands damaged by bark beetle, slightly managed windthrown forest stands left for the natural succession, and freshly harvested windthrown stands. After two years of research a total of 7,294 Collembola specimens were recorded belonging to 93 species. We recorded the highest collembolan abundance and species richness in the reference stands within catchments of both lakes, while both given parameters were considerably lower in harmed forest stands. To summarize, the disturbance led to a general decrease of Collembola communities.

  20. Life history as a predictor of salamander recovery rate from timber harvest in southern appalachian forests, USA.

    PubMed

    Connette, Grant M; Semlitsch, Raymond D

    2013-12-01

    Forest management often represents a balance between social, economic, and ecological objectives. In the eastern United States, numerous studies have established that terrestrial salamander populations initially decline in abundance following timber harvest, yet the large-scale and long-term consequences are relatively unknown. We used count data from terrestrial survey points to examine the relation between salamander abundance and historic timber harvest while accounting for imperfect detection of individuals. Overall, stream- and terrestrial-breeding salamanders appeared to differ by magnitude of population decline, rate of population recovery, and extent of recolonization from surrounding forest. Specifically, estimated abundance of both species groups was positively associated with stand age and recovery rates were predicted to increase over time for red-legged salamanders (Plethodon shermani) and decrease in stream-breeding species. Abundance of stream-breeding salamanders was predicted to reach a peak by 100 years after timber harvest, and the population growth rate of red-legged salamanders was predicted to undergo a significant increase 100 years after harvest. Estimated abundance of stream-breeding salamanders in young forest stands was also negatively associated with the distance to adjacent forest, a result that suggests immigration has a role in the recovery of these species. Our results indicate that salamander abundance in young forest stands may be only modestly lower than in more mature forest but that full recovery from timber harvest may take a substantial amount of time and that species life history may affect patterns of recovery. Historia de Vida como un Vaticinador de la Tasa de Recuperación de una Salamandra a la Colecta de Madera en los Bosques del Sur de los Apalaches, E.U.A. PMID:24033390

  1. NEO Test Stand Analysis

    NASA Technical Reports Server (NTRS)

    Pike, Cody J.

    2015-01-01

    A project within SwampWorks is building a test stand to hold regolith to study how dust is ejected when exposed to the hot exhaust plume of a rocket engine. The test stand needs to be analyzed, finalized, and fabrication drawings generated to move forward. Modifications of the test stand assembly were made with Creo 2 modeling software. Structural analysis calculations were developed by hand to confirm if the structure will hold the expected loads while optimizing support positions. These calculations when iterated through MatLab demonstrated the optimized position of the vertical support to be 98'' from the far end of the stand. All remaining deflections were shown to be under the 0.6'' requirement and internal stresses to meet NASA Ground Support Equipment (GSE) Safety Standards. Though at the time of writing, fabrication drawings have yet to be generated, but are expected shortly after.

  2. A new computer approach to map mixed forest features and postprocess multispectral data

    NASA Technical Reports Server (NTRS)

    Kan, E. P.

    1976-01-01

    A computer technique for mapping mixed softwood and hardwood stands in multispectral satellite imagery of forest regions is described. The purpose of the technique is to obtain smoother resource maps useful in timber harvesting operations. The computer program relies on an algorithm which assesses the size and similarity of adjacent sections on satellite imagery (Landsat-1 data is used) and constructs, through an iteration of the basic algorithm, a more general map of timber mixtures, eliminating the mottled appearance of the raw imagery. Despite difficulties in the experimental analysis of a Texas forest, apparently due to relatively low resolution of the Landsat data, the computer classification approach outlined is suggested as a generally applicable method of creating serviceable maps from multispectral imagery.

  3. The Stimulus test stand

    SciTech Connect

    Christofek, L.; Rapidis, P.; Reinhard, A.; /Fermilab

    2005-06-01

    The Stimulus Test Stand was originally constructed and assembled for testing the SVX2 ASIC readout and then upgraded for SVX3 ASIC prototyping and testing. We have modified this system for SVX4 ASIC [1] prototype testing. We described the individual components below. Additional details for other hardware for SVX4 testing can be found in reference [2]. We provide a description of the Stimulus Test Stand used for prototype testing of the SVX4 chip.

  4. Carbon stocks across a chronosequence of thinned and unmanaged red pine (Pinus resinosa) stands

    USGS Publications Warehouse

    Powers, Matthew D.; Kolka, Randall K.; Bradford, John B.; Palik, Brian J.; Fraver, Shawn; Jurgensen, Martin F.

    2012-01-01

    Forests function as a major global C sink, and forest management strategies that maximize C stocks offer one possible means of mitigating the impacts of increasing anthropogenic CO2 emissions. We studied the effects of thinning, a common management technique in many forest types, on age-related trends in C stocks using a chronosequence of thinned and unmanaged red pine (Pinus resinosa) stands ranging from 9 to 306 years old. Live tree C stocks increased with age to a maximum near the middle of the chronosequence in unmanaged stands, and increased across the entire chronosequence in thinned stands. C in live understory vegetation and C in the mineral soil each declined rapidly with age in young stands but changed relatively little in middle-aged to older stands regardless of management. Forest floor C stocks increased with age in unmanaged stands, but forest floor C decreased with age after the onset of thinning around age 40 in thinned stands. Deadwood C was highly variable, but decreased with age in thinned stands. Total ecosystem C increased with stand age until approaching an asymptote around age 150. The increase in total ecosystem C was paralleled by an age-related increase in total aboveground C, but relatively little change in total belowground C. Thinning had surprisingly little impact on total ecosystem C stocks, but it did modestly alter age-related trends in total ecosystem C allocation between aboveground and belowground pools. In addition to characterizing the subtle differences in C dynamics between thinned and unmanaged stands, these results suggest that C accrual in red pine stands continues well beyond the 60–100 year management rotations typical for this system. Management plans that incorporate longer rotations and thinning in some stands could play an important role in maximizing C stocks in red pine forests while meeting other objectives including timber extraction, biodiversity conservation, restoration, and fuel reduction goals.

  5. Determining Stand Parameters from Uas-Based Point Clouds

    NASA Astrophysics Data System (ADS)

    Yilmaz, V.; Serifoglu, C.; Gungor, O.

    2016-06-01

    In Turkey, forest management plans are produced by terrestrial surveying techniques for 10 or 20 year periods, which can be considered quite long to maintain the sustainability of forests. For a successful forest management plan, it is necessary to collect accurate information about the stand parameters and store them in dynamic and robust databases. The position, number, height and closure of trees are among the most important stand parameters required for a forest management plan. Determining the position of each single tree is challenging in such an area consisting of too many interlocking trees. Hence, in this study, an object-based tree detection methodology has been developed in MATLAB programming language to determine the position of each tree top in a highly closed area. The developed algorithm uses the Canopy Height Model (CHM), which is computed from the Digital Terrain Model (DTM) and Digital Surface Model (DSM) generated by using the point cloud extracted from the images taken from a UAS (Unmanned Aerial System). The heights of trees have been determined by using the CHM. The closure of the trees has been determined with the written MATLAB script. The results show that the developed tree detection methodology detected more than 70% of the trees successfully. It can also be concluded that the stand parameters may be determined by using the UAS-based point clouds depending on the characteristics of the study area. In addition, determination of the stand parameters by using point clouds reduces the time needed to produce forest management plans.

  6. Petroleum basins of Sakhalin and adjacent shelf

    SciTech Connect

    Mavrinski, Y.; Koblov, E. )

    1993-09-01

    Sixty-seven oil and gas fields have been discovered on Sakhalin and the adjacent shelf but the distribution of fields is uneven in north Sakhalin, south Sakhalin, and the Tatar basins. The sedimentary cover is composed of sandy, clayey, and siliceous rocks, with volcanogenic and coal-bearing deposits of Upper Cretaceous, Paleogene, and Neogene 8-12 km thick. Marine clayey and siliceous oil source rocks are regionally developed in the section at different stratigraphic levels; the organic matter is of mixed type and the content varies from 0.5 to 1.5%. The upper Oligocene and middle-upper Miocene source rocks in the north Sakhalin basin are typical, and the organic carbon content ranges from 1 to 5%. The level of organic matter catagenesis and conversion into hydrocarbons is high because of the high differential geothermal gradient in the basins, 30-50[degrees]C per km. Porous sandstones in the Miocene form the reservoirs in all fields with the exception of Okruzhnoye, where the pay zone is a siliceous claystone. Growth-fault rollovers and anticlines form the main traps ranging in area from 5 to 300 km[sup 2], with amplitudes between 100 and 600 m. both stratigraphic and structural traps have been identified. Considerable volumes of reserves are associated with the Miocene deposits of north Sakhalin, which are characterized by an optimum combination of oil source rocks, focused migration paths, and thick sequences of reservoirs and cap rocks. Six large fields have been discovered in the past 15 yr. Oil and condensate reserves stand at over 300 million MT, and gas reserves are about 900 billion m[sup 3].

  7. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  8. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  9. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  10. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  11. Effects of thinning intensities on transpiration and productivity of 50-year-old Pinus koraeinsis stands

    NASA Astrophysics Data System (ADS)

    Park, Juhan; Kim, Taekyu; Moon, Minkyu; Cho, Sungsik; Ryu, Daun; Kim, Hyun Seok

    2015-04-01

    This study investigated the effects of thinning intensities on stand transpiration and productivity of 50-year-old Korean pine forests for two years. Forest thinning, which removes some fraction of trees from stand, is widely conducted for reducing competition between remaining trees, improving tree productivity, reducing the risk of natural fire, and thus maintaining healthy forest. Forest thinning alters the microclimatic conditions such as radiation distribution within canopy, vapor pressure deficit, and amount of available soil water. These changes influence on the tree water use, and related productivity. Thinning was conducted on March, 2012 with two intensities (Control, Light-thinning (20%), and Heavy-thinning (40% of tree density)). Transpiration was estimated from sap flux density, which was measured with Granier-type thermal dissipation sensors. Tree diameter growth was measured with dendrometer, and converted to tree productivity using allometric equations developed specifically in our study sites. The climatic conditions showed little differences between two years. During the first growing season after thinning, stand transpiration was ca. 20% and 42% lower on light-thinning and heavy-thinning stand, respectively, even though sap flux density were higher in thinned stand. The difference in stand transpiration among treatments showed seasonal trends, so it was larger on summer when soil moisture was abundant due to monsoon, but was diminished on spring and autumn when soil moisture was limited. Tree-level productivity increased ca. 8% and 21% on light-thinning and heavy thinning stand, respectively. However, stand net primary production was ca. 20% lower on light-thinning stand, and ca. 31% on heavy-thinning stand. As a result, water use efficiency increased only in heavy-thinning stand. During the second growing season after thinning, stand transpiration was ca. 19% lower on light-thinning stand, and ca. 37% lower on heavy-thinning stand. The reduction

  12. Lichen conservation in heavily managed boreal forests.

    PubMed

    McMullin, Richard Troy; Thompson, Ian D; Newmaster, Steven G

    2013-10-01

    Lichens are an important component of the boreal forest, where they are long lived, tend to accumulate in older stands, and are a major food source for the threatened woodland caribou (Rangifer tarandus caribou). To be fully sustainable, silvicultural practices in the boreal forest must include the conservation of ecological integrity. Dominant forest management practices, however, have short-term negative effects on lichen diversity, particularly the application of herbicides. To better understand the long-term effects of forest management, we examined lichen regeneration in 35 mixed black spruce (Picea mariana) and jack pine (Pinus banksiana) forest stands across northern Ontario to determine recovery following logging and postharvest silvicultural practices. Our forest stands were 25-40 years old and had undergone 3 common sivilcultural treatments that included harvested and planted; harvested, planted, and treated with N-[phosphonomethyl] glycine (glyphosate); and harvested, planted, and treated with 2,4-dichlorophenoxyacetic acid (2,4-D). Forest stands with herbicide treatments had lower lichen biomass and higher beta and gamma diversity than planted stands that were not treated chemically or control stands. In northwestern Ontario, planted stands that were not treated chemically had significantly greater (p < 0.05) alpha diversity than stands treated with herbicides or control stands. Our results show that common silvicultural practices do not emulate natural disturbances caused by wildfires in the boreal forest for the lichen community. We suggest a reduction in the amount of chemical application be considered in areas where lichen biomass is likely to be high and where the recovery of woodland caribou is an objective. PMID:23869621

  13. Designing a carbon market that protects forests in developing countries.

    PubMed

    Niesten, Eduard; Frumhoff, Peter C; Manion, Michelle; Hardner, Jared J

    2002-08-15

    incentives to clear natural forests through CDM crediting for afforestation and reforestation, we recommend for the first commitment period that policymakers establish an early base year, such as 1990, such that lands cleared after that year would be ineligible for crediting. We further recommend an exception to this rule for CDM projects that are explicitly designed to promote natural forest restoration and that pass rigorous environmental impact review. Restoration efforts are typically most effective on lands that are adjacent to standing forests and hence likely to have been recently cleared. Thus, we recommend for these projects establishing a more recent base year, such as 2000. For the second and subsequent commitment periods, we recommend that climate policymakers act to restrain inter-annex leakage and its impacts by ensuring that crediting for forest management in industrialized countries is informed by modelling efforts to anticipate the scale of leakage associated with different Annex I 'Land use, land-use change and forestry' policy options, and coupled with effective measures to protect natural forests in developing countries. The latter should include expanding the options permitted under the CDM to carbon crediting for projects that protect threatened forests from deforestation and forest degradation. Ultimately, carbon market incentives for forest clearing can be reduced and incentives for forest conservation most effectively strengthened by fully capturing carbon emissions associated with deforestation and forest degradation in developing countries under a future emissions cap. Finally, we note that these recommendations have broader relevance to any forest-based measures to reduce greenhouse-gas emissions developed outside of the specific context of the Kyoto Protocol. PMID:12460503

  14. [Eco-environment and nutrient accumulation of sharptooth oak stands in southern slope of Mt. Qinling].

    PubMed

    Liu, Guangquan; Ni, Wenjin; Liu, Huifang; Gravenhorst, G

    2002-05-01

    Based on the date from chemical analysis of 10,785 botanical and 1489 edaphic samples, the amount of nutrients accumulated in soil layer (0-60 cm) of sharptooth oak stands, the total biomass of the stands and their contents of accumulated nutrients, and the amount of litter and its contents of accumulated nutrients in southern slope of Mt. Qinling were calculated. To a certain extent, the biomass and the nutrient accumulation of the stands were increased with stand densities and stand ages from thin to high or from young to old, similar to the utilization efficiency of the stands to soil nutrient elements and the trunk canopy ratio. The tree composition of the stands much more influenced nutrient accumulation contents than the biomass. The more broad-leaved tree of species composition, the higher nutrient accumulation contents of stands. In the same region biomass and its nutrient contents of the stands with similar site factors and stand factors had not remarkably difference among different forest-types, but had a difference among various forest types and species composition. In different region, biomass and its nutrient contents of the stands with similar site factors and stand factors had a difference with the sequence of south slope > north slope, middle section > east section or west section. The utilization efficiency of soil nutrient elements by the stands was decreased from lower to higher elevation, from the south to north slope, from middle to east and west section. PMID:12181886

  15. Looking northeast from Test Stand 'A' superstructure towards Test Stand ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking northeast from Test Stand 'A' superstructure towards Test Stand 'D' tower (4223/E-24, left background), Test Stand 'C' tower (4217/E-18, center), and Test Stand 'B' (4215/E-16, right foreground). - Jet Propulsion Laboratory Edwards Facility, Edwards Air Force Base, Boron, Kern County, CA

  16. PPT Thrust Stand

    NASA Technical Reports Server (NTRS)

    Haag, Thomas W.

    1995-01-01

    A torsional-type thrust stand has been designed and built to test Pulsed Plasma Thrusters (PPT's) in both single shot and repetitive operating modes. Using this stand, momentum per pulse was determined strictly as a function of thrust stand deflection, spring constant, and natural frequency. No empirical corrections were required. The accuracy of the method was verified using a swinging impact pendulum. Momentum transfer data between the thrust stand and the pendulum were consistent to within 1%. Following initial calibrations, the stand was used to test a Lincoln Experimental Satellite (LES-8/9) thruster. The LES-8/9 system had a mass of approximately 7.5 kg, with a nominal thrust to weight ratio of 1.3 x 10(exp -5). A total of 34 single shot thruster pulses were individually measured. The average impulse bit per pulse was 266 microN-s, which was slightly less than the value of 300 microN-s published in previous reports on this device. Repetitive pulse measurements were performed similar to ordinary steady-state thrust measurements. The thruster was operated for 30 minutes at a repetition rate of 132 pulses per minute and yielded an average thrust of 573 microN. Using average thrust, the average impulse bit per pulse was estimated to be 260 microN-s, which was in agreement with the single shot data. Zero drift during the repetitive pulse test was found to be approximately 1% of the measured thrust.

  17. The legacy of forest harvest and burning on ecosystem carbon storage in the northern midwest, USA

    NASA Astrophysics Data System (ADS)

    Gough, C. M.; Vogel, C. S.; Harrold, K. H.; George, K. D.; Curtis, P. S.

    2005-12-01

    Over 90 % of the forested area in the upper Great Lakes region was harvested by the early 20th century. In many cases, harvests were followed by uncontrolled burns, similar to current patterns of disturbance in many developing countries. While afforestation in the northern midwest has resulted in increased regional carbon (C) storage, the rate of C storage by forests will depend on the severity of prior disturbance and consequent changes in site quality. We were interested in how long the legacy of poor management practices from the early 20th century would be reflected in forest C storage rates. We investigated C cycling and storage following disturbance in mixed deciduous forests of northern lower Michigan, USA. Study plots ranged in age from 6 to 68 yrs and were created following experimental clear-cut harvesting and fire disturbance. Annual C storage was estimated biometrically from measurements of wood, leaf, fine root, and woody debris mass, mass losses to herbivory, soil carbon content, and soil respiration. Maximum annual carbon storage, or net ecosystem production (NEP), in the disturbed stands was 50 % lower than that of adjacent, undisturbed forest. This decrease was caused by a reduction in site quality following disturbance. However, during regrowth the cut and burned forest rapidly became a net C sink, storing 0.86 Mg C ha-1 yr-1 after six yrs. Carbon storage reached a peak of 1.00 Mg C ha-1 yr-1 after 50 yrs and declined to 0.57 Mg C ha-1 yr-1 after 68 yrs. Above- and below-ground net primary production (NPP) averaged 42 and 59 % of total NPP, respectively, with fine root litter production accounting for 57 % of total NPP. Soil heterotrophic respiration was high, ranging from 4.55 Mg C ha-1 yr-1 in the 6-yr-old stand to 5.74 Mg C ha-1 yr-1 in the 50-yr-old stand. Soil C and coarse woody debris pools exhibited a U-shaped trend over time following disturbance. Mineral soil and coarse woody debris pools lost C at a combined annual rate of 1.10 Mg C ha-1

  18. Exploration of a rare population of Chinese chestnut in North America: stand dynamics, health and genetic relationships

    PubMed Central

    Miller, Amy C.; Woeste, Keith E.; Anagnostakis, Sandra L.; Jacobs, Douglass F.

    2014-01-01

    With the transport of plants around the globe, exotic species can readily spread disease to their native relatives; however, they can also provide genetic resistance to those relatives through hybrid breeding programmes. American chestnut (Castanea dentata) was an abundant tree species in North America until its decimation by introduced chestnut blight. To restore chestnut in North America, efforts are ongoing to test putative blight-resistant hybrids of Castanea dentata and Chinese chestnut (Castanea mollissima), but little is known about the ecology of C. mollissima. In a forest in northeastern USA in which C. mollissima has become established, we explored questions of stand dynamics, health and genetic relationships of C. mollissima offspring to an adjacent parent orchard. We found that C. mollissima was adapted and randomly distributed among native species in this relatively young forest. The genetics of the C. mollissima population compared with its parents indicated little effect of selection pressure as each of the parent trees contributed at least one offspring. The ease with which this exotic species proliferated calls to question why C. mollissima is rare elsewhere in forests of North America. It is likely that a time window of low animal predation allowed seedlings to establish, and the shallow soil at this site limited the maximum forest canopy height, permitting the characteristically short-statured C. mollissima to avoid suppression. Our results indicate that because C. mollissima exhibited pioneer species characteristics, hybrids between C. mollissima and C. dentata have the potential to be successful pioneer species of future forests in North America, and we challenge the paradigm that exotic tree species are wholly detrimental to native biodiversity. We contend that exotic tree species should be assessed not only by their level of threat to native species, but also by their potential positive impacts on ecosystems via hybrid breeding programmes

  19. Exploration of a rare population of Chinese chestnut in North America: stand dynamics, health and genetic relationships.

    PubMed

    Miller, Amy C; Woeste, Keith E; Anagnostakis, Sandra L; Jacobs, Douglass F

    2014-01-01

    With the transport of plants around the globe, exotic species can readily spread disease to their native relatives; however, they can also provide genetic resistance to those relatives through hybrid breeding programmes. American chestnut (Castanea dentata) was an abundant tree species in North America until its decimation by introduced chestnut blight. To restore chestnut in North America, efforts are ongoing to test putative blight-resistant hybrids of Castanea dentata and Chinese chestnut (Castanea mollissima), but little is known about the ecology of C. mollissima. In a forest in northeastern USA in which C. mollissima has become established, we explored questions of stand dynamics, health and genetic relationships of C. mollissima offspring to an adjacent parent orchard. We found that C. mollissima was adapted and randomly distributed among native species in this relatively young forest. The genetics of the C. mollissima population compared with its parents indicated little effect of selection pressure as each of the parent trees contributed at least one offspring. The ease with which this exotic species proliferated calls to question why C. mollissima is rare elsewhere in forests of North America. It is likely that a time window of low animal predation allowed seedlings to establish, and the shallow soil at this site limited the maximum forest canopy height, permitting the characteristically short-statured C. mollissima to avoid suppression. Our results indicate that because C. mollissima exhibited pioneer species characteristics, hybrids between C. mollissima and C. dentata have the potential to be successful pioneer species of future forests in North America, and we challenge the paradigm that exotic tree species are wholly detrimental to native biodiversity. We contend that exotic tree species should be assessed not only by their level of threat to native species, but also by their potential positive impacts on ecosystems via hybrid breeding programmes

  20. Atmospheric deposition in coniferous and deciduous tree stands in Poland

    NASA Astrophysics Data System (ADS)

    Kowalska, Anna; Astel, Aleksander; Boczoń, Andrzej; Polkowska, Żaneta

    2016-05-01

    The objective of this study was to assess the transformation of precipitation in terms of quantity and chemical composition following contact with the crown layer in tree stands with varied species composition, to investigate the effect of four predominant forest-forming species (pine, spruce, beech, and oak) on the amount and composition of precipitation reaching forest soils, and to determine the sources of pollution in atmospheric precipitation in forest areas in Poland. The amount and chemical composition (pH, electric conductivity, alkalinity, and chloride, nitrate, sulfate, phosphate, ammonium, calcium, magnesium, sodium, potassium, iron aluminum, manganese, zinc, copper, total nitrogen, and dissolved organic carbon contents) of atmospheric (bulk, BP) and throughfall (TF) precipitation were studied from January to December 2010 on twelve forest monitoring plots representative of Polish conditions. The study results provided the basis for the determination of the fluxes of pollutants in the forest areas of Poland and allowed the comparison of such fluxes with values provided in the literature for European forest areas. The transformation of precipitation in the canopy was compared for different tree stands. The fluxes of substances in an open field and under canopy were influenced by the location of the plot, including the regional meteorological conditions (precipitation amounts), vicinity of the sea (effect of marine aerosols), and local level of anthropogenic pollution. Differences between the plots were higher in TF than in BP. The impact of the vegetation cover on the chemical composition of precipitation depended on the region of the country and dominant species in a given tree stand. Coniferous species tended to cause acidification of precipitation, whereas deciduous species increased the pH of TF. Pine and oak stands enriched precipitation with components that leached from the canopy (potassium, manganese, magnesium) to a higher degree than spruce and

  1. Forest discrimination with multipolarization imaging radar

    NASA Technical Reports Server (NTRS)

    Ford, J. P.; Wickland, D. E.

    1985-01-01

    The relations between polarization signatures and biophysical characteristics through a range of different forest environments were investigated using airborne synthetic-aperture (SAR) images acquired at L-band on March 1, 1984 in South Carolina. SAR data acquired in four linear polarization states with 10-m spatial resolution were encoded as color composite images and compared to US Forest Service forest stand data. The most useful correlative forest data were stand basal area, forest age, site condition index, and forest management type. It is found that the multipolarization images discriminate variation in tree density or difference in the amount of understory, but no evidence has been found for discrimination between evergreen and deciduous forest types.

  2. Standing wave compressor

    DOEpatents

    Lucas, Timothy S.

    1991-01-01

    A compressor for compression-evaporation cooling systems, which requires no moving parts. A gaseous refrigerant inside a chamber is acoustically compressed and conveyed by means of a standing acoustic wave which is set up in the gaseous refrigerant. This standing acoustic wave can be driven either by a transducer, or by direct exposure of the gas to microwave and infrared sources, including solar energy. Input and output ports arranged along the chamber provide for the intake and discharge of the gaseous refrigerant. These ports can be provided with optional valve arrangements, so as to increase the compressor's pressure differential. The performance of the compressor in either of its transducer or electromagnetically driven configurations, can be optimized by a controlling circuit. This controlling circuit holds the wavelength of the standing acoustical wave constant, by changing the driving frequency in response to varying operating conditions.

  3. Richness of lichen species, especially of threatened ones, is promoted by management methods furthering stand continuity.

    PubMed

    Boch, Steffen; Prati, Daniel; Hessenmöller, Dominik; Schulze, Ernst-Detlef; Fischer, Markus

    2013-01-01

    Lichens are a key component of forest biodiversity. However, a comprehensive study analyzing lichen species richness in relation to several management types, extending over different regions and forest stages and including information on site conditions is missing for temperate European forests. In three German regions (Schwäbische Alb, Hainich-Dün, Schorfheide-Chorin), the so-called Biodiversity Exploratories, we studied lichen species richness in 631 forest plots of 400 m(2) comprising different management types (unmanaged, selection cutting, deciduous and coniferous age-class forests resulting from clear cutting or shelterwood logging), various stand ages, and site conditions, typical for large parts of temperate Europe. We analyzed how lichen species richness responds to management and habitat variables (standing biomass, cover of deadwood, cover of rocks). We found strong regional differences with highest lichen species richness in the Schwäbische Alb, probably driven by regional differences in former air pollution, and in precipitation and habitat variables. Overall, unmanaged forests harbored 22% more threatened lichen species than managed age-class forests. In general, total, corticolous, and threatened lichen species richness did not differ among management types of deciduous forests. However, in the Schwäbische-Alb region, deciduous forests had 61% more lichen species than coniferous forests and they had 279% more threatened and 76% more corticolous lichen species. Old deciduous age classes were richer in corticolous lichen species than young ones, while old coniferous age-classes were poorer than young ones. Overall, our findings highlight the importance of stand continuity for conservation. To increase total and threatened lichen species richness we suggest (1) conserving unmanaged forests, (2) promoting silvicultural methods assuring stand continuity, (3) conserving old trees in managed forests, (4) promoting stands of native deciduous tree species

  4. Carbon storage in mountainous headwater streams: The role of old-growth forest and logjams

    NASA Astrophysics Data System (ADS)

    Beckman, Natalie D.; Wohl, Ellen

    2014-03-01

    We measured wood piece characteristics and particulate organic matter (POM) in stored sediments in 30 channel-spanning logjams along headwater streams in the Colorado Front Range, USA. Logjams are on streams flowing through old-growth (>200 years), disturbed (<200 years, natural disturbance), or altered (<200 years, logged) subalpine conifer forest. We examined how channel-spanning logjams influence riverine carbon storage (measured as the total volatile carbon fraction of stored sediment and instream wood). Details of carbon storage associated with logjams reflect age and disturbance history of the adjacent riparian forest. A majority of the carbon within jams is stored as wood. Wood volume is significantly larger in old-growth and disturbed reaches than in altered reaches. Carbon storage also differs in relation to forest characteristics. Sediment from old-growth streams has significantly higher carbon content than altered streams. Volume of carbon stored in jam sediment correlates with jam wood volume in old-growth and disturbed forests, but not in altered forests. Forest stand age and wood volume within a jam explain 43% of the variation of carbon stored in jam sediment. First-order estimates of the amount of carbon stored within a stream reach show an order of magnitude difference between disturbed and altered reaches. Our first-order estimates of reach-scale riverine carbon storage suggest that the carbon per hectare stored in streams is on the same order of magnitude as the carbon stored as dead biomass in terrestrial subalpine forests of the region. Of particular importance, old-growth forest correlates with more carbon storage in rivers.

  5. Standing waves braneworlds

    NASA Astrophysics Data System (ADS)

    Gogberashvili, Merab; Mantidze, Irakli; Sakhelashvili, Otari; Shengelia, Tsotne

    2016-05-01

    The class of nonstationary braneworld models generated by the coupled gravitational and scalar fields is reviewed. The model represents a brane in a spacetime with single time and one large (infinite) and several small (compact) spacelike extra dimensions. In some particular cases the model has the solutions corresponding to the bulk gravi-scalar standing waves bounded by the brane. Pure gravitational localization mechanism of matter particles on the node of standing waves, where the brane is placed, is discussed. Cosmological applications of the model is also considered.

  6. Forest nutrition management

    SciTech Connect

    Binkley, D.

    1986-01-01

    This book draws on the fields of silviculture, soil studies, ecology, and economics to provide information on how to enhance the nutritional status of forest soils in order to increase their long-term stand productivity. It covers the use of fertilizers to enhance biological nitrogen fixation and how the nutrition status of forests is affected by other operations, such as harvesting and site preparation. Methods for assessing nutrient status, the economics of nutrition management, and models to aid in decision-making are included.

  7. Modelling the standing timber volume of Baden-Württemberg-A large-scale approach using a fusion of Landsat, airborne LiDAR and National Forest Inventory data

    NASA Astrophysics Data System (ADS)

    Maack, Joachim; Lingenfelder, Marcus; Weinacker, Holger; Koch, Barbara

    2016-07-01

    Remote sensing-based timber volume estimation is key for modelling the regional potential, accessibility and price of lignocellulosic raw material for an emerging bioeconomy. We used a unique wall-to-wall airborne LiDAR dataset and Landsat 7 satellite images in combination with terrestrial inventory data derived from the National Forest Inventory (NFI), and applied generalized additive models (GAM) to estimate spatially explicit timber distribution and volume in forested areas. Since the NFI data showed an underlying structure regarding size and ownership, we additionally constructed a socio-economic predictor to enhance the accuracy of the analysis. Furthermore, we balanced the training dataset with a bootstrap method to achieve unbiased regression weights for interpolating timber volume. Finally, we compared and discussed the model performance of the original approach (r2 = 0.56, NRMSE = 9.65%), the approach with balanced training data (r2 = 0.69, NRMSE = 12.43%) and the final approach with balanced training data and the additional socio-economic predictor (r2 = 0.72, NRMSE = 12.17%). The results demonstrate the usefulness of remote sensing techniques for mapping timber volume for a future lignocellulose-based bioeconomy.

  8. Do natural disturbances or the forestry practices that follow them convert forests to early-successional communities?

    PubMed

    Brewer, J Stephen; Bertz, Christine A; Cannon, Jeffery B; Chesser, Jason D; Maynard, Erynn E

    2012-03-01

    Stand-replacing natural disturbances in mature forests are traditionally seen as events that cause forests to revert to early stages of succession and maintain species diversity. In some cases, however, such transitions could be an artifact of salvage logging and may increase biotic homogenization. We present initial (two-year) results of a study of the effects of tornado damage and the combined effects of tornado damage and salvage logging on environmental conditions and ground cover plant communities in mixed oak-pine forests in north central Mississippi. Plots were established in salvage-logged areas, adjacent to plots established before the storm in unlogged areas, spanning a gradient of storm damage intensity. Vegetation change directly attributable to tornado damage was driven primarily by a reduction in canopy cover but was not consistent with a transition to an early stage of succession. Although we observed post-storm increases of several disturbance indicators (ruderals), we also observed significant increases in the abundance of a few species indicative of upland forests. Increases in flowering were just as likely to occur in species indicative of forests as in species indicative of open woodlands. Few species declined as a result of the tornado, resulting in a net increase in species richness. Ruderals were very abundant in salvage-logged areas, which contained significantly higher amounts of bare ground and greater variance in soil penetrability than did damaged areas that were not logged. In contrast to unlogged areas severely damaged by the tornado, most upland forest indicators were not abundant in logged areas. Several of the forest and open-woodland indicators that showed increased flowering in damaged areas were absent or sparse in logged areas. Species richness was lower in salvage-logged areas than in adjacent damaged areas but similar to that in undamaged areas. These results suggest that salvage logging prevented positive responses of several

  9. Free-Standing Canes.

    ERIC Educational Resources Information Center

    Ehresman, Paul

    1995-01-01

    A precane device, called the "free-standing cane," was developed to help children with blindness along with other disabilities. The cane detects obstacles; guides the user's hands into a relaxed, static position in front of the hips; facilitates postural security and control; and offers tactile and kinesthetic feedback. (JDD)

  10. Landscape dynamics of northeastern forests

    NASA Technical Reports Server (NTRS)

    Canham, Charles D.; Silander, John A., Jr.; Civco, Daniel L.

    1994-01-01

    This project involves collaborative research with Stephen W. Pacala and Simon A. Levin of Princeton University to calibrate, test, and analyze models of heterogeneous forested landscapes containing a diverse array of habitats. The project is an extension of previous, NASA-supported research to develop a spatially-explicit model of forest dynamics at the scale of an individual forest stand (hectares to square kilometer spatial scales). That model (SORTIE) has been thoroughly parameterized from field studies in the modal upland environment of western Connecticut. Under our current funding, we are scaling-up the model and parameterizing it for the broad range of upland environments in the region. Our most basic goal is to understand the linkages between stand-level dynamics (as revealed in our previous research) and landscape-level dynamics of forest composition and structure.

  11. Forest clearing and sex ratio in forest-dwelling wood ant Formica aquilonia

    NASA Astrophysics Data System (ADS)

    Sorvari, Jouni; Hakkarainen, Harri

    2007-05-01

    Sex ratios of ants have been shown to vary with food resource levels in several studies, but it is not known whether forest clear-cutting has any effect on sex ratio of aphid-tending forest-dwelling ants. We investigated whether the offspring sex ratio of the forest dwelling ant Formica aquilonia varied as a response to clear-cutting. We found that the proportion of males was smaller in clear-cuts than in adjacent forests. Our results are among the first showing that anthropogenic changes in forest structures may have a potential to modify sex ratios of social insects and other forest-dwelling animals.

  12. A tool for assessing ecological status of forest ecosystem

    NASA Astrophysics Data System (ADS)

    Rahman Kassim, Abd; Afizzul Misman, Muhammad; Azahari Faidi, Mohd; Omar, Hamdan

    2016-06-01

    Managers and policy makers are beginning to appreciate the value of ecological monitoring of artificially regenerated forest especially in urban areas. With the advent of more advance technology in precision forestry, high resolution remotely sensed data e.g. hyperspectral and LiDAR are becoming available for rapid and precise assessment of the forest condition. An assessment of ecological status of forest ecosystem was developed and tested using FRIM campus forest stand. The forest consisted of three major blocks; the old growth artificially regenerated native species forests, naturally regenerated forest and recent planted forest for commercial timber and other forest products. Our aim is to assess the ecological status and its proximity to the mature old growth artificially regenerated stand. We used airborne LiDAR, orthophoto and thirty field sampling quadrats of 20x20m for ground verification. The parameter assessments were grouped into four broad categories: a. forest community level-composition, structures, function; landscape structures-road network and forest edges. A metric of parameters and rating criteria was introduced as indicators of the forest ecological status. We applied multi-criteria assessment to categorize the ecological status of the forest stand. The paper demonstrates the application of the assessment approach using FRIM campus forest as its first case study. Its potential application to both artificially and naturally regenerated forest in the variety of Malaysian landscape is discussed

  13. Interannual Variation in Stand Transpiration is Dependent Upon Tree Species

    NASA Astrophysics Data System (ADS)

    Ewers, B. E.; Mackay, D. S.; Burrows, S. N.; Ahl, D. E.; Samanta, S.

    2003-12-01

    In order to successfully predict transpirational water fluxes from forested watersheds, interannual variability in transpiration must be quantified and understood. In a heterogeneous forested landscape in northern Wisconsin, we quantified stand transpiration across four forest cover types representing more than 80 percent of the land area in order to 1) quantify differences in stand transpiration and leaf area over two years and 2) determine the mechanisms governing the changes in transpiration over two years. We measured sap flux in eight trees of each tree species in the four cover types. We found that in northern hardwoods, the leaf area of sugar maple increased between the two measurement years with transpiration per unit ground area increasing even more than could be explained by leaf area. In an aspen stand, tent caterpillars completely defoliated the stand for approximately a month until a new set of leaves flushed out. The new set of leaves resulted in a lower leaf area but the same transpiration per unit leaf area indicating there was no physiological compensation for the lower leaf area. At the same time, balsam fir growing underneath the aspen increased their transpiration rate in response to greater light penetration through the dominant aspen canopy Red pine had a thirty percent change in leaf area within a growing season due to multiple cohorts of leaves and transpiration followed this leaf area dynamic. In a forested wetland, white cedar transpiration was proportional to surface water depth between the two years. Despite the specific tree species' effects on stand transpiration, all species displayed a minimum water potential regulation resulting in a saturating response of transpiration to vapor pressure deficit that did not vary across the two years. This physiological set point will allow future water flux models to explain mechanistically interannual variability in transpiration of this and similar forests.

  14. Deciduous Tree Species Alter Nitrogen and Phosphorus Availability in Mid-successional Alaskan Boreal Forest

    NASA Astrophysics Data System (ADS)

    Melvin, A. M.; Mack, M. C.; Johnstone, J. F.; Schuur, E. A.

    2013-12-01

    In Alaskan boreal forest, increased fire severity associated with climate change is altering successional processes and ecosystem nutrient dynamics. Fire is a common disturbance in Interior Alaska and typically burns forests dominated by black spruce (Picea mariana), a tree species associated with slow nutrient turnover and high soil organic matter accumulation rates. Historically, low severity fires have driven black spruce regeneration post-fire, thereby maintaining slow nutrient cycling rates and large soil organic matter stocks. In contrast, high severity fires consume the organic layer and can lead to the establishment of deciduous tree species on exposed mineral soil, which produce less recalcitrant leaf litter and exhibit faster nutrient cycling rates. To improve our understanding of the long-term impacts of tree species composition on nutrient cycling in boreal forest, we quantified nitrogen (N) cycling rates and estimated soil N, phosphorus (P), and base cation pools in adjacent, mid-successional stands of black spruce and Alaska paper birch (Betula neoalaskana) that established following a 1960 fire near Fairbanks, Alaska. Results indicate significantly higher net N mineralization in paper birch soils relative to black spruce for both the fibric organic layer and top 10 cm of mineral soil during 30-day and 90-day lab incubation studies. Net nitrification was significantly higher in the paper birch fibric layer after 90 days. Total soil N concentrations did not differ between paper birch and black spruce stands, however the black spruce organic layer was significantly larger than that of birch, resulting in larger organic layer N stocks (130 vs. 87 g N m2). In contrast, total P concentrations were significantly higher in the organic layer in birch forest, but the total P stocks did not differ significantly between species because of the larger mass of soil organic matter in the black spruce. These findings suggest that a shift towards greater deciduous

  15. A SPATIAL ANALYSIS OF THE FINE ROOT BIOMASS FROM STAND DATA IN THE PACIFIC NORTHWEST

    EPA Science Inventory

    High spatial variability of fine roots in natural forest stands makes accurate estimates of stand-level fine root biomass difficult and expensive to obtain by standard coring methods. This study uses aboveground tree metrics and spatial relationships to improve core-based estima...

  16. 20. Building 202, detail of stand A, rocket test stand ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. Building 202, detail of stand A, rocket test stand in test cell. View looking southeast. - Rocket Engine Testing Facility, GRC Building No. 202, NASA Glenn Research Center, Cleveland, Cuyahoga County, OH

  17. 43 CFR 420.3 - Adjacent lands.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Adjacent lands. 420.3 Section 420.3 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR...-managing agencies on adjacent lands (both public and private)....

  18. 43 CFR 420.3 - Adjacent lands.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Adjacent lands. 420.3 Section 420.3 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR...-managing agencies on adjacent lands (both public and private)....

  19. 43 CFR 420.3 - Adjacent lands.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Adjacent lands. 420.3 Section 420.3 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR OFF-ROAD VEHICLE USE § 420.3 Adjacent lands. When administratively feasible, the regulation of off-road vehicle use on Reclamation lands will...

  20. 43 CFR 420.3 - Adjacent lands.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Adjacent lands. 420.3 Section 420.3 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR...-managing agencies on adjacent lands (both public and private)....

  1. 43 CFR 420.3 - Adjacent lands.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Adjacent lands. 420.3 Section 420.3 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR OFF-ROAD VEHICLE USE § 420.3 Adjacent lands. When administratively feasible, the regulation of...

  2. Forest Management.

    ERIC Educational Resources Information Center

    Weicherding, Patrick J.; And Others

    This bulletin deals with forest management and provides an overview of forestry for the non-professional. The bulletin is divided into six sections: (1) What Is Forestry Management?; (2) How Is the Forest Measured?; (3) What Is Forest Protection?; (4) How Is the Forest Harvested?; (5) What Is Forest Regeneration?; and (6) What Is Forest…

  3. Statewide LANDSAT inventory of California forests

    NASA Technical Reports Server (NTRS)

    Likens, W.; Peterson, D. (Principal Investigator)

    1981-01-01

    Six forest cover categories were mapped, along with 10 general land cover classes. To map the state's 100 million acres, 1.6 acre mapping units were utilized. Map products were created. Standing forest acreage for the state was computed to be 26.8 million acres.

  4. Get up, Stand up

    ERIC Educational Resources Information Center

    Melia, Ed

    2009-01-01

    Ignorance about dyslexia meant a miserable school experience for Barrie Hughes. He was in his 50s when he found the courage to stand up in front of a classroom of learners and admit he couldn't read. Barrie, who is now 59 and works for the parks department of Brighton and Hove Council, only began to learn how to read words in the last three years…

  5. Forest discrimination with multipolarization imaging radar

    NASA Technical Reports Server (NTRS)

    Ford, J. P.; Wickland, D. E.

    1985-01-01

    The use of radar polarization diversity for discriminating forest canopy variables on airborne synthetic-aperture radar (SAR) images is evaluated. SAR images were acquired at L-Band (24.6 cm) simultaneously in four linear polarization states (HH, HV, VH, and VV) in South Carolina on March 1, 1984. In order to relate the polarization signatures to biophysical properties, false-color composite images were compared to maps of forest stands in the timber compartment. In decreasing order, the most useful correlative forest data are stand basal area, forest age, site condition index, and forest management type. It is found that multipolarization images discriminate variation in tree density and difference in the amount of understory, but do not discriminate between evergreen and deciduous forest types.

  6. Effects of Bromelia pinguin (Bromeliaceae) on soil ecosystem function and fungal diversity in the lowland forests of Costa Rica

    PubMed Central

    2014-01-01

    Background Bromelia pinguin (Bromeliaceae) is a terrestrial bromeliad commonly found under forest stands throughout the Neotropics that has been shown to have antifungal activity in vitro. We have hypothesized that this bromeliad would also have an effect on the fungal populations in nearby soil by decreasing fungaldiversity and negatively impacting C and N cycle-related activities. A previous study in the lowland forest of Costa Rica showed the soil beneath these bromeliads had decreased fungal ITS DNA and differences in C and N levels compared to adjacent primary forest soils. Results In this follow-up study, we found that the bromeliad soils had lower rates of C and N biomass development and lower phenol oxidase activity (suggesting less decreased fungal decomposition activity). The results of T-RFLP and cloning-based taxonomic analyses showed the community level diversity and abundance of fungal ITS DNA was less in bromeliad soils. Sequence analysis of fungal ITS DNA clones showed marked differences in fungal community structure between habitats of Basidiomycota (Tremellales, Agricales, Thelephorales), Ascomycota (Helotiales), and Zycomycota populations. Conclusions The data show there to be differences in the soil nutrient dynamics and fungal community structure and activity associated with these bromeliads, as compared to the adjacent primary forest. This suggests the possibility that the anti-fungal activity of the bromeliad extends into the soil. The bromeliad-dense regions of these primary forest habitats provide a unique natural micro-habitat within the forests and the opportunity to better identify the role of fungal communities in the C and N cycles in tropical soils. PMID:24885984

  7. Impact of grazing management with large herbivores on forest ground flora and bramble understorey

    NASA Astrophysics Data System (ADS)

    Van Uytvanck, Jan; Hoffmann, Maurice

    2009-07-01

    We investigated whether grazing management with large herbivores is appropriate to reduce expanding bramble ( Rubus sp.) in an ancient forest in Flanders (N. Belgium). We further studied interaction effects of four years (all year-round) grazing and Rubus cover on the presence, cover, and flowering of five forest ground flora species (unpalatable: Anemone nemorosa and Primula elatior; palatable: Hyacinthoides non-scripta, Vinca minor and Hedera helix). We collected data on eight transects and in 412 plots in adjacent grazed and ungrazed forest and used baseline datasets of 1996 and 2002 in the same area (i.e. before grazing). In a field experiment, we simulated grazing (by clipping) and trampling (by pressing a weight) in eight homogeneous A. nemorosa vegetation stands. Large Rubus thickets had a clear negative impact on cover and flowering of A. nemorosa due to competition for light. Four years of cattle grazing reduced bramble cover by more than 50%, but then the limiting factor for A. nemorosa cover and flowering shifted to trampling damage. We also found lower cover and flowering of H. non-scripta in grazed plots, as a consequence of direct grazing. The evergreen species V. minor and H. helix totally disappeared from the grazed forest. Simulated once-only effects of grazing and trampling had a small and short term negative impact on cover of A. nemorosa, but flowering was strongly reduced. Grazing reduced biomass with 25-30% in the following years. Year-round grazing with large herbivores is an appropriate measure for bramble control in forests, but negative effects on ground flora are possible if grazing pressure is high. A low or moderate grazing pressure (<0.25 animal units ha -1 y -1) should be maintained in landscape mosaics with grassland and forest; or intermittent periods of non-grazing should be provided to maintain forest ground flora diversity.

  8. Plant and bird diversity in natural forests and in native and exotic plantations in NW Portugal

    NASA Astrophysics Data System (ADS)

    Proença, Vânia M.; Pereira, Henrique M.; Guilherme, João; Vicente, Luís

    2010-03-01

    Forest ecosystems have been subjected to continuous dynamics between deforestation and forestation. Assessing the effects of these processes on biodiversity could be essential for conservation planning. We analyzed patterns of species richness, diversity and evenness of plants and birds in patches of natural forest of Quercus spp. and in stands of native Pinus pinaster and exotic Eucalyptus globulus in NW Portugal. We analyzed data of forest and non-forest species separately, at the intra-patch, patch and inter-patch scales. Forest plant richness, diversity and evenness were higher in oak forest than in pine and eucalypt plantations. In total, 52 species of forest plants were observed in oak forest, 33 in pine plantation and 28 in eucalypt plantation. Some forest species, such as Euphorbia dulcis, Omphalodes nitida and Eryngium juresianum, were exclusively or mostly observed in oak forest. Forest bird richness and diversity were higher in both oak and pine forests than in eucalypt forest; evenness did not differ among forests. In total, 16 species of forest birds were observed in oak forest, 18 in pine forest and 11 in eucalypt forest. Species such as Certhia brachydactyla, Sitta europaea and Dendrocopos major were common in oak and/or pine patches but were absent from eucalypt stands. Species-area relationships of forest plants and forest birds in oak patches had consistently a higher slope, at both the intra and inter-patch scales, than species-area relationships of forest species in plantations and non-forest species in oak forest. These findings demonstrate the importance of oak forest for the conservation of forest species diversity, pointing the need to conserve large areas of oak forest due to the apparent vulnerability of forest species to area loss. Additionally, diversity patterns in pine forest were intermediate between oak forest and eucalypt forest, suggesting that forest species patterns may be affected by forest naturalness.

  9. CARBON BALANCE OF FOREST BIOMES IN THE FORMER USSR

    EPA Science Inventory

    Sources and sinks of carbon and the sequestration potential of forest biomes in the former Soviet Union (FSU) were assessed under non-equilibrium conditions by considering, 1) net ecosystem productivity (NEP) of different age forest stands and actual forest coverage, 2) carbon fl...

  10. Effects of Forest Disturbances on Forest Structural Parameters Retrieval from Lidar Waveform Data

    NASA Technical Reports Server (NTRS)

    Ranson, K, Lon; Sun, G.

    2011-01-01

    The effect of forest disturbance on the lidar waveform and the forest biomass estimation was demonstrated by model simulation. The results show that the correlation between stand biomass and the lidar waveform indices changes when the stand spatial structure changes due to disturbances rather than the natural succession. This has to be considered in developing algorithms for regional or global mapping of biomass from lidar waveform data.

  11. CARBON ISOTOPE DISCRIMINATION AND GROWTH RESPONSE OF OLD PINUS PONDEROSA TREES TO STAND DENSITY REDUCTIONS

    EPA Science Inventory

    Stand density reductions have been proposed as a method by which old-growth ponderosa pine (Pinus ponderosa) forests of North America can be converted back to pre-1900 conditions, thereby reducing the danger of catastrophic forest fires and insect attacks while increasing product...

  12. A slight recovery of soils from Acid Rain over the last three decades is not reflected in the macro nutrition of beech (Fagus sylvatica) at 97 forest stands of the Vienna Woods.

    PubMed

    Berger, Torsten W; Türtscher, Selina; Berger, Pétra; Lindebner, Leopold

    2016-09-01

    Rigorous studies of recovery from soil acidification are rare. Hence, we resampled 97 old-growth beech stands in the Vienna Woods. This study exploits an extensive data set of soil (infiltration zone of stemflow and between trees area at different soil depths) and foliar chemistry from three decades ago. It was hypothesized that declining acidic deposition is reflected in soil and foliar chemistry. Top soil pH within the stemflow area increased significantly by 0.6 units in both H2O and KCl extracts from 1984 to 2012. Exchangeable Ca and Mg increased markedly in the stemflow area and to a lower extent in the top soil of the between trees area. Trends of declining base cations in the lower top soil were probably caused by mobilization of organic S and associated leaching with high amounts of sulfate. Contents of C, N and S decreased markedly in the stemflow area from 1984 to 2012, suggesting that mineralization rates of organic matter increased due to more favorable soil conditions. It is concluded that the top soil will continue to recover from acidic deposition. However, in the between trees areas and especially in deeper soil horizons recovery may be highly delayed. The beech trees of the Vienna Woods showed no sign of recovery from acidification although S deposition levels decreased. Release of historic S even increased foliar S contents. Base cation levels in the foliage declined but are still adequate for beech trees. Increasing N/nutrient ratios over time were considered not the result of marginally higher N foliar contents in 2012 but of diminishing nutrient uptake due to the decrease in ion concentration in soil solution. The mean foliar N/P ratio already increased to the alarming value of 31. Further nutritional imbalances will predispose trees to vitality loss. PMID:27344089

  13. A slight recovery of soils from Acid Rain over the last three decades is not reflected in the macro nutrition of beech (Fagus sylvatica) at 97 forest stands of the Vienna Woods✰

    PubMed Central

    Berger, Pétra; Lindebner, Leopold

    2016-01-01

    Rigorous studies of recovery from soil acidification are rare. Hence, we resampled 97 old-growth beech stands in the Vienna Woods. This study exploits an extensive data set of soil (infiltration zone of stemflow and between trees area at different soil depths) and foliar chemistry from three decades ago. It was hypothesized that declining acidic deposition is reflected in soil and foliar chemistry. Top soil pH within the stemflow area increased significantly by 0.6 units in both H2O and KCl extracts from 1984 to 2012. Exchangeable Ca and Mg increased markedly in the stemflow area and to a lower extent in the top soil of the between trees area. Trends of declining base cations in the lower top soil were probably caused by mobilization of organic S and associated leaching with high amounts of sulfate. Contents of C, N and S decreased markedly in the stemflow area from 1984 to 2012, suggesting that mineralization rates of organic matter increased due to more favorable soil conditions. It is concluded that the top soil will continue to recover from acidic deposition. However, in the between trees areas and especially in deeper soil horizons recovery may be highly delayed. The beech trees of the Vienna Woods showed no sign of recovery from acidification although S deposition levels decreased. Release of historic S even increased foliar S contents. Base cation levels in the foliage declined but are still adequate for beech trees. Increasing N/nutrient ratios over time were considered not the result of marginally higher N foliar contents in 2012 but of diminishing nutrient uptake due to the decrease in ion concentration in soil solution. The mean foliar N/P ratio already increased to the alarming value of 31. Further nutritional imbalances will predispose trees to vitality loss. PMID:27344089

  14. Seasonal diets of insectivorous birds using canopy gaps in a bottomland forest.

    SciTech Connect

    Moorman, Christopher, E.; Bowen, Liessa, T.; Kilgo, John, C.; Sorenson, Clyde E.; Hanula, James L.; Horn, Scott; Ulyshen, Mike D.

    2007-07-01

    ABSTRACT. Little is known about how insectivorous bird diets are influenced by arthropod availability and about how these relationships vary seasonally. We captured birds in forest-canopy gaps and adjacent mature forest during 2001 and 2002 at the Savannah River Site in Barnwell County, South Carolina, and flushed their crops to gather information about arthropods eaten during four periods: spring migration, breeding, postbreeding, and fall migration. Arthropod availability for foliage- and ground-gleaning birds was examined by leaf clipping and pitfall trapping. Coleopterans and Hemipterans were used by foliage- and ground-gleaners more than expected during all periods, whereas arthropods in the orders Araneae and Hymenoptera were used as, or less than, expected based on availability during all periods. Ground-gleaning birds used Homopterans and Lepidopterans in proportions higher than availability during all periods. Arthropod use by birds was consistent from spring through all migration, with no apparent seasonal shift in diet. Based on concurrent studies, heavily used orders of arthropods were equally abundant or slightly less abundant in canopy gaps than in the surrounding mature forest, but bird species were most frequently detected in gaps. Such results suggest that preferential feeding on arthropods by foliage-gleaning birds in p p habitats reduced arthropod densities or, alternatively, that bird use of gap and forest habitat was not determined y food resources. The abundance of arthropods across the stand may have allowed birds to remain in the densely vegetated gaps where thick cover provides protection from predators.

  15. Forest in My Neighborhood: An Exercise Using Aerial Photos to Engage Students in Forest Ecology & Land Use History

    ERIC Educational Resources Information Center

    Matlack, Glenn R.; McEwan, Ryan W.

    2008-01-01

    Human activity has profoundly altered the deciduous forest of the eastern United States. Modern forest is a patchwork of stands of varying ages, sizes, and shapes reflecting a complex history of land use. Much modern forest is nestled in and around human communities, and faces the threat of imminent clearance for residential and commercial…

  16. Taking Stock and Standing down

    ERIC Educational Resources Information Center

    Peeler, Tom

    2009-01-01

    Standing down is an action the military takes to review, regroup, and reorganize. Unfortunately, it often comes after an accident or other tragic event. To stop losses, the military will "stand down" until they are confident they can resume safe operations. Standing down is good for everyone, not just the military. In today's fast-paced world,…

  17. Mixed-Forest Species Establishment in a Monodominant Forest in Central Africa: Implications for Tropical Forest Invasibility

    PubMed Central

    Peh, Kelvin S.-H.; Sonké, Bonaventure; Séné, Olivier; Djuikouo, Marie-Noël K.; Nguembou, Charlemagne K.; Taedoumg, Hermann; Begne, Serge K.; Lewis, Simon L.

    2014-01-01

    Background Traits of non-dominant mixed-forest tree species and their synergies for successful co-occurrence in monodominant Gilbertiodendron dewevrei forest have not yet been investigated. Here we compared the tree species diversity of the monodominant forest with its adjacent mixed forest and then determined which fitness proxies and life history traits of the mixed-forest tree species were most associated with successful co-existence in the monodominant forest. Methodology/Principal Findings We sampled all trees (diameter in breast height [dbh]≥10 cm) within 6×1 ha topographically homogenous areas of intact central African forest in SE Cameroon, three independent patches of G. dewevrei-dominated forest and three adjacent areas (450–800 m apart). Monodominant G. dewevrei forest had lower sample-controlled species richness, species density and population density than its adjacent mixed forest in terms of stems with dbh≥10 cm. Analysis of a suite of population-level characteristics, such as relative abundance and geographical distribution, and traits such as wood density, height, diameter at breast height, fruit/seed dispersal mechanism and light requirement–revealed after controlling for phylogeny, species that co-occur with G. dewevrei tend to have higher abundance in adjacent mixed forest, higher wood density and a lower light requirement. Conclusions/Significance Our results suggest that certain traits (wood density and light requirement) and population-level characteristics (relative abundance) may increase the invasibility of a tree species into a tropical closed-canopy system. Such knowledge may assist in the pre-emptive identification of invasive tree species. PMID:24844914

  18. Effect of Radiocesium Transfer on Ambient Dose Rate in Forest Environment

    NASA Astrophysics Data System (ADS)

    Kato, Hiroaki; Onda, Yuichi; Loffredo, Nicolas; Hisadome, Keigo; Kawamori, Ayumi

    2014-05-01

    We investigated the transfer of canopy-intercepted radiocesium to the forest floor following the Fukushima Daiichi nuclear power plant accident. The cesium-137 (Cs-137) contents of throughfall, stemflow, and litterfall were monitored in two coniferous stands (plantation of Japanese cedar) and a deciduous broad-leaved forest stand (beech with red pine). We also measured an ambient dose rate at different height in the forest by using a survey meter (TCS-172B, Hitachi-Aloka Medical, LTD.) and a portable Ge gamma-ray detector (Detective-DX-100T, Ortec, Ametek, Inc.). In decreasing order of total Cs-137 deposition from the canopy to forest floor were the mature cedar stand, the young cedar stand, and the broad-leaved forest. The ambient dose rate in forest exhibited height dependency and its vertical distribution varied by forest type and stand age. The ambient dose rate showed an exponential decrease with time for all the forest sites, however the decreasing trend differed depending on the height of dose measurement and forest type. The ambient dose rates at the canopy (approx. 10 m-) decreased earlier than physical attenuation of radiocesium, whereas those at the forest floor varied among three forest stands. These data suggested that an ambient dose rate in forest environment can be variable in spatially and temporally reflecting the transfer of radiocesium from canopy to forest floor.

  19. Water transport dynamics in trees and stands

    SciTech Connect

    Pallardy, S.G.; Cermak, J.; Ewers, F.W.; Kaufmann, M.R.; Parker, W.C.; Sperry, J.S.

    1995-07-01

    Water transport dynamics in trees and stands of conifers have certain features that are characteristic of this group and are at least rare among angiosperms. Among these features is the xylem transport system that is dependent on tracheids for long-distance water transport. Tracheid-containing xylem is relatively inefficient, a property that can reduce submaximum allowable rates of gas exchange, but tracheids also offer substantial capacity for water storage and high resistance to freezing-induced dysfunction. Thus, they are quite compatible with the typical evergreen habit and long transpiration season of conifers. At the stand level, canopy transpiration in conifers is primarily controlled by stomatal conductance. In contrast, in dense canopies of angio-sperms, particularly those of tropical forests with limited air mixing, stand transpiration is limited by radiation input rather than by stomatal control. Because of their evergreen habit a greater proportion of evapotranspiration in conifer forests is associated with evaporation of water intercepted by the tree crowns. Other features of transport dynamics are characteristic of most conifers, but are not unique to this group. Among these features are typically shallow root systems that often must supply water in winter to replace transpiration needs of evergreen species, common occurrence of mycorrhizae that enhance mineral and water uptake, and drought tolerance adaptations that include elements of both dehydration avoidance (e.g., stomatal closure under water stress, shifts in allocation of dry matter to below-ground sinks) and dehydration tolerance (e.g., capacity for acclimation of photosynthetic apparatus to drought, osmotic adjustment). Transpiration rates from conifer foliage often are lower than those of deciduous angiosperms, probably because of the lower maximum capacity of tracheid-bearing xylem to transport water.

  20. 76 FR 315 - Sisters Ranger District; Deschutes National Forest; Oregon; Popper Vegetation Management Project

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-04

    ... proposed action to manage forest fuels and forest stand densities, including areas within a designated... vegetation density to lessen the risk that ongoing disturbance agents such as wildfire, insects, and...

  1. High Brightness Test Stand

    SciTech Connect

    Birx, D.L.; Caporaso, G.J.; Boyd, J.K.; Hawkins, S.A.; Poor, S.E.; Reginato, L.L.; Rogers, D. Jr.; Smith, M.W.

    1985-08-07

    The High Brightness Test Stand is a 2 MeV, less than or equal to 10 kA electron accelerator module. This accelerator module, designed as an upgrade prototype for the Advanced Test Accelerator (ATA), combines solid state nonlinear magnetic drives with state-of-the-art induction linac technology. The facility serves a dual role, as it not only provides a test bed for this new technology, but is used to develop high brightness electron optics. We will both further describe the accelerator, as well as present some of the preliminary electron optics measurements.

  2. Ecological effects of pipeline construction through deciduous forested wetlands, Midland County, Michigan. Topical report, October 1990--August 1992

    SciTech Connect

    Rastorfer, J.R.; Van Dyke, G.D.; Zellmer, S.D.; Wilkey, P.L.

    1995-04-01

    This study is designed to record vegetational changes induced by the construction of a large-diameter gas pipeline through deciduous forested wetlands. Two second-growth wetland sites mapped Lenawee soils were selected in Midland County, Michigan: Site 1, a younger stand subjected to recent selective logging, and Site 2, a more mature stand. The collection of ecological data to analyze plant succession on the right-of-way (ROW) and the effects of the developing ROW plant communities on adjacent forest communities was initiated in 1989. Cover class estimates were made for understory and ROW plant species on the basis of 1 {times} 1{minus}m quadrats. Individual stem diameters and species counts were recorded for overstory plants in 10{minus}m quadrats. Although long-term studies have not been completed, firm baseline data were established for comparative analyses with future sampling. Current data indicate that vegetation became well-established on the ROW within one year and subsequently increased in coverage. About 65% of the species were wetland indicators, and the dominants included seeded and natural invading species; nevertheless, some elements of the original flora regenerated and persist. The plants of the ecotone understories of both sites changed from their original composition as a result of the installation of the gas pipeline. Although some forest species persist at both sites, the ecotone of Site I was influenced more by the seeded species, whereas the natural invaders were more important at Site 2.

  3. 75 FR 32738 - Gallatin National Forest-Hebgen Lake Ranger District; MT; Lonesome Wood Vegetation Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-09

    ...This integrated forest vegetation management project is designed to achieve the goals of increased firefighter and public safety, reduced wildland fire risks to adjacent property and Forest Service infrastructure, and to enhance aspen forest communities that are in decline. Proposed forest thinning and associated activities target the removal of excessive surface, ladder and crown fuel. This......

  4. [Forest degradation/decline: research and practice].

    PubMed

    Zhu, Jiao-Jun; Li, Feng-Qin

    2007-07-01

    As one of the most critical environmental problems in the 21st century, forest degradation has been facing worldwide. There are many definitions about forest degradation, but its common features are the permanent loss of forests, stand structure destructed, forest quality decreased, and forest functions lowered. Forest decline or tree decline in fact is one of the causes of forest degradation, which includes the general reduction of trees in vigor, low level growth of trees in productivity, death of trees, and even, decline of soil fertility. Many researches indicated that deforestation is the permanent loss of forests in area, which is shifted to other land uses. Deforestation is the product of the interactions between environmental, social, economic, cultural, and political forces at work in any given country/region, and thus, more and more attention is focused on the negative socioeconomic and environmental effects after forest degradation, especially on the reduction of forest area induced by deforestation. The effects of any decisions or policies in national and international levels on forest degradation induced by deforestation have been paid attention as well. How to make efforts and strengthen the worldwide cooperation to combat the forest degradation induced by deforestation must be challenged to find appropriate solutions. There are many researches on forest decline, because of its complexity and uncertainties. The major causes of forest decline include: 1) pollution from both industry and agriculture, 2) stress factors, e.g., desiccation, 3) changes in stand dynamics, 4) decline disease of forest or diseases of complex etiology, 5) degradation of productivity and/or soil fertility in pure plantation forests. Forest degradation in China is similar to that all over the world, but with the characteristics in forest components, i.e., 1) secondary forests are the major forest resources, 2) China has the most plantation forests in the world, some of which have

  5. GOAT ROCKS WILDERNESS AND ADJACENT ROADLESS AREAS, WASHINGTON.

    USGS Publications Warehouse

    Church, S.E.; Close, T.J.

    1984-01-01

    The Goat Rocks Wilderness and adjacent roadless areas are a rugged, highly forested, scenic area located on the crest of the Cascade Range in south-central Washington. Several mineral claims have been staked in the area. Mineral surveys were conducted. Geochemical, geophysical, and geologic investigations indicate that three areas have probable mineral-resource potential for base metals in porphyry-type deposits. Available data are not adequate to permit definition of the potential for oil and gas. There is little likelihood for the occurrence of other kinds of energy resources in the area. Evaluation of resource potential in the three areas identified as having probable mineral-resource potential could be improved by more detailed geochemical studies and geologic mapping.

  6. Southern Idaho`s forest land outside national forests, 1991. Forest Service resource bulletin

    SciTech Connect

    Chojnacky, D.C.

    1995-05-01

    The report presents 59 summary tables of forest statistics for land in southern Idaho outside National Forests. The tables show forest land area, tree numbers, wood volume and growth, and tree mortality organized by ownership, stand, and tree classification variables. These stimates are derived from summarization of 292 field plots and over 100,000 photo points using a two-phase sample design. Of the 292 field plots, 91 were remeasurements of plots established in 1981. The sampling was done in 1991 by the U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Forest Inventory and Analysis (FIA) unit located in Ogden, UT. Besides presenting detailed tables, the report briefly explains key FIA terminology, overviews the table formats, highlights some results, and discusses inventory design and data reliability.

  7. Dynamics of fine roots in five Chinese temperate forests.

    PubMed

    Quan, Xiankuai; Wang, Chuankuan; Zhang, Quanzhi; Wang, Xingchang; Luo, Yiqi; Bond-Lamberty, Ben

    2010-07-01

    We used a minirhizotron method to investigate spatial and temporal dynamics of fine roots (diameter < or =2 mm) in five Chinese temperate forests: Mongolian oak forest, aspen-birch forest, hardwood forest, Korean pine plantation and Dahurian larch plantation. Fine root dynamics were significantly influenced by forest type, soil layer, and sampling time. The grand mean values varied from 1.99 to 3.21 mm cm(-2) (root length per minirhizotron viewing area) for the fine root standing crop; from 6.7 to 11.6 microm cm(-2) day(-1) for the production; and from 3.2 to 6.1 microm cm(-2) day(-1) for the mortality. All forests had a similar seasonal "sinusoidal" pattern of standing crop, and a "unimodal" pattern of production. However, the seasonal dynamics of the mortality were largely unsynchronized with those of the production. The minimum values of standing crop, production and mortality occurred in March for all forests, whereas the maximum values and occurrence time differed among forest types. The standing crop, production and mortality tended to decrease with soil depth. The different spatiotemporal patterns of fine roots among the forests highlight the need for forest-specific measurements and modeling of fine root dynamics and forest carbon allocation. PMID:20217175

  8. Landscape-Scale Disturbances Modified Bird Community Dynamics in Successional Forest Environment

    PubMed Central

    Zhao, Qing; Azeria, Ermias T.; Le Blanc, Mélanie-Louise; Lemaître, Jérôme; Fortin, Daniel

    2013-01-01

    Ecosystem-based forest management strives to develop silvicultural practices that best emulate natural disturbances such as wildfire to conserve biodiversity representative of natural forest ecosystems. Yet, current logging practices alter forest structure and reduce the proportion of old-growth forest and, consequently, can exert long-term effects on the dynamics of forest biota. The stand- and landscape-scale factors driving bird community dynamics in post-disturbance environment remain poorly understood. In this study, we examined bird community dynamics along successional gradients in boreal ecosystems originating from fire and logging in landscapes dominated by old-growth forest. We tested if bird species richness and community compositions in clear-cutting stands became comparable to those in natural stands after 70 years, and identified the relative contributions of stand- and landscape-scale forest attributes in bird community dynamics. Based on records of bird occurrences at 185 field sites in natural and clearcutting stands, we demonstrate that (1) both forest structures and bird communities underwent evident changes along successional gradients in post-clearcutting environment; (2) bird species richness and community composition in 60- to 70-years-old clearcutting stands still differed from those in 50- to 79-years-old natural stands, in spite of the fact that most forest attributes of clearcutting stands became comparable to those of natural stands after 40 years; and (3) landscape disturbances contributed more than stand characteristics in explaining the lack of convergence of mature forest species, residents, and short-distance migrants in post-clearcutting environment. Our study points out that more regards should be paid to improve the landscape configuration of the managed forests, and implies that old-growth forest retention within logged areas, combined with selection cutting and prolonged logging rotations, can better emulate fire and alleviate

  9. Arboreal lichen in uncut and partially cut subalpine fir stands in woodland caribou habitat, northern Idaho and southeastern British Columbia

    USGS Publications Warehouse

    Rominger, Eric M.; Allen-Johnson, Lydia; Oldemeyer, John L.

    1994-01-01

    To better understand the effects of partial cutting on arboreal lichen production within woodland caribou (Rangifer tarandus caribou) habitat, lichen was hand picked from 1228 branches on 307 subalpine fir (Abies lasiocarpa) trees in Idaho (ID), and in British Columbia (BC). Lichen biomass from partially cut stands was compared with biomass on trees from adjacent uncut stands at each site. Arboreal lichen biomass did not differ significantly between uncut and partially cut stands. Total number of branches per tree did not differ significantly between uncut and partially cut stands. Live branches had more lichen than dead branches. Species composition of arboreal lichen changed in partially cut stands compared with adjacent uncut stands. The ratio of live to dead branches was substantially different within the BC partial cut.

  10. Culturable bacterial populations associated with ectomycorrhizae of Norway spruce stands with different degrees of decline in the Czech Republic.

    PubMed

    Avidano, Lorena; Rinaldi, Maurizio; Gindro, Roberto; Cudlín, Pavel; Martinotti, Maria Giovanna; Fracchia, Letizia

    2010-01-01

    The aim of this study was to determine which species of culturable bacteria are associated with ectomycorrhizae (ECM) of Norway spruce (Picea abies (L.) Karst) in the Sudety Mountains, exposed for years to atmospheric pollutants, acid rain, and climatic stress, and to identify particular species that have adapted to those conditions. Biolog identification was performed on bacterial species from ECM of adult spruce trees and seedlings of stands with low, intermediate, and high forest decline. Bacterial diversity in ECM associated with adult spruce trees, seedlings, and seedlings grown on monoliths was calculated; although the expected values appeared to vary widely, no significant differences among sites were observed. Dendrograms based on the identified bacterial species showed that stands with low forest decline clustered separately from the others. Principal component analysis of the normalized data for ECM-associated species showed a clear separation between stands with high forest decline and stands with low forest decline for seedlings and a less evident separation for adult spruce trees. In conclusion, shifts in ECM-associated culturable bacterial populations seem to be associated with forest decline in Norway spruce stands. Some bacterial species were preferentially associated with mycorrhizal roots depending on the degree of forest decline; this was more evident in seedlings where the species Burkholderia cepacia and Pseudomonas fluorescens were associated with, respectively, ECM of the most damaged stands and those with low forest decline. PMID:20130694

  11. Forested wetland mitigation resulting from discharges of cooling water into streams

    SciTech Connect

    Nelson, E.A. )

    1993-01-01

    The Savannah River Swamp is a 3020-ha forested wetland on the floodplain of the Savannah River and is located on the US Department of Energy's Savannah River Site (SRS) near Aiken, South Carolina. Historically, the swamp consisted of [approximately]50% bald cypress-water tupelo stands, 40% mixed bottomland hardwood stands, and 10% shrub, marsh, and open water. The hydrology was controlled by flooding the Savannah River and by flow from four creeks that drain into the swamp prior to flow into the Savannah River. Upstream dams have caused some alteration of the water levels and timing of flooding within the floodplain. Major impacts to the swamp hydrology occurred with the completion of the production reactors and one coal-fired powerhouse at the SRS in the early 1950s. Water, often in excess of 40 to 50[degrees]C was discharged into one of the small streams from 1954 to 1988, at various levels, ranging from 20 to 40 times the prior flow rate of the stream. This had a major impact on the adjacent swamp land, with erosion, silting, and vegetation destruction. The Final Environmental Impact Statement, Continued Operation of K, L, and P Reactors, Savannah River Site, Aiken, South Carolina, and the subsequent record of decision directed that these areas be restored to functional forested wetland status to the extent possible. This paper describes work begun to reach that objective.

  12. NITROGEN CONCENTRATIONS IN LOADING SOURCES FOR THREE COASTAL LAGOONS FROM ATMOSPHERIC AND WATERSHED SOURCES, ADJACENT COASTAL MARSHES, TIDAL EXCHANGES

    EPA Science Inventory

    Abstract and Oral Presentation Gulf Estuarine Research Society.

    Standing stocks and inputs of total dissolved nitrogen (TDN) to three coastal lagoons, hereafter referred to as Kee's Bayou, Gongora, and State Park, with varying adjacent land-use, geomorphology, and water re...

  13. On the time-course of adjacent and non-adjacent transposed-letter priming

    PubMed Central

    Ktori, Maria; Kingma, Brechtsje; Hannagan, Thomas; Holcomb, Phillip J.; Grainger, Jonathan

    2014-01-01

    We compared effects of adjacent (e.g., atricle-ARTICLE) and non-adjacent (e.g., actirle-ARTICLE) transposed-letter (TL) primes in an ERP study using the sandwich priming technique. TL priming was measured relative to the standard double-substitution condition. We found significantly stronger priming effects for adjacent transpositions than non-adjacent transpositions (with 2 intervening letters) in behavioral responses (lexical decision latencies), and the adjacent priming effects emerged earlier in the ERP signal, at around 200 ms post-target onset. Non-adjacent priming effects emerged about 50 ms later and were short-lived, being significant only in the 250-300 ms time-window. Adjacent transpositions on the other hand continued to produce priming in the N400 time-window (300-500 ms post-target onset). This qualitatively different pattern of priming effects for adjacent and non-adjacent transpositions is discussed in the light of different accounts of letter transposition effects, and the utility of drawing a distinction between positional flexibility and positional noise. PMID:25364497

  14. Effect of species composition on carbon and nitrogen stocks in forest floor and mineral soil in Norway spruce and European beech mixed forests

    NASA Astrophysics Data System (ADS)

    Andivia, Enrique; Rolo, Víctor; Jonard, Mathieu; Formánek, Pavel; Ponette, Quentin

    2015-04-01

    Management of existing forests has been identified as the main strategy to enhance carbon sequestration and to mitigate the impact of climate change on forest ecosystems. In this direction, the conversion of Norway spruce monospecific stands into mixed stands by intermingling individuals of European beech is an ongoing trend in adaptive forest management strategies, especially in Central Europe. However, studies assessing the effect of changes in tree species composition on soil organic carbon (SOC) and nitrogen stocks are still scarce and there is a lack of scientific evidence supporting tree species selection as a feasible management option to mitigate the effects of predicted future climatic scenarios. We compared C and N stocks in the forest floor (litter and humus) and the top 10 cm of mineral soil in two monospecific stands of Norway spruce and European beech and in a mixed stand of both species. The effect of tree species composition on the C and N stocks and its spatial distribution was evaluated based on litterfall, root production, elevation and canopy opening, and by using a combination of modelling and geostatistical techniques. C stock was highest in the Norway spruce and the mixed stands, while N stock was highest in the mixed stand and lowest under European beech, with intermediate values in the Norway spruce stand. Each forest type showed differences in forest floor properties, suggesting that species composition is an important factor governing forest floor characteristics, including C and N stocks. The distribution of C and N stocks between forest soil layers was different for each forest type. C and N stocks were highest in the hummus layer under Norway spruce, whereas both stocks were lowest in the European beech stand. On the other hand, the mixed stand showed the highest C and N accumulation in the uppermost mineral soil layer, while the monospecific stands showed similar values. Litterfall was the main contribution to C and N stocks of the

  15. Modeling of SAR returns from a red pine stand

    NASA Technical Reports Server (NTRS)

    Lang, R. H.; Kilic, O.; Chauhan, N. S.; Ranson, J.

    1992-01-01

    Bright P-band radar returns from red pine forests have been observed on synthetic aperture radar (SAR) images in Bangor, Maine. A plot of red pine trees was selected for the characterization and modeling to understand the cause of the high P-band returns. The red pine stand under study consisted of mature trees. Diameter at breast height (DBH) measurements were made to determine stand density as a function of tree diameter. Soil moisture and bulk density measurements were taken along with ground rough surface profiles. Detailed biomass measurements of the needles, shoots, branches, and trunks were also taken. These site statistics have been used in a distorted Born approximation model of the forest. Computations indicate that the direct-reflected or the double-bounce contributions from the ground are responsible for the high observed P-band returns for HH polarization.

  16. Postfire Forest Recovery in California's National Forests

    NASA Astrophysics Data System (ADS)

    Welch, K.; Young, T.; Safford, H.

    2012-12-01

    Due to fire suppression policies and other management practices over the last century, many low- to mid-elevation forest types in the Sierra Nevada have accumulated high fuel loads that promote stand-replacing high-intensity fires. Current and future projected trends in climate are predicted to increase the occurrence of such fires. We established over 1,000 plots in a range of elevations, environments, forest types, climate zones and fire severity classes to provide insight into the factors that promote natural tree regeneration after wildfires, the limiting factors in species establishment, and the differences in post-fire responses of conifers and hardwoods. We employed a standardized protocol that measured site characteristics, seedling densities, and woody plant growth. Preliminary results reveal that fire severity generally has a unimodal relationship with rates of natural regeneration, although effects of site and local environment act to modulate the shape of the relationship. Above low to moderate severities, natural regeneration rates of all tree species decrease with increasing severity, possibly due to a combination of factors including seed mortality, increasing distance to the nearest living seed tree, and more severe microclimatic conditions. Though hardwoods (oaks) are able to both seed and resprout from top-killed root crowns in a postfire environment, conifers still have the numerical advantage over hardwoods through seeding alone. We did not find evidence that shrubs have a strong either facilitative or competitive effect on conifer seedling establishment or growth in the first five years of forest recovery. Understanding forest recovery and regeneration processes after high severity fires is critical to appropriately applying management strategies on National Forest lands.

  17. 15. ELEVATED CAMERA STAND, SHOWING LINE OF CAMERA STANDS PARALLEL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. ELEVATED CAMERA STAND, SHOWING LINE OF CAMERA STANDS PARALLEL TO SLED TRACK. Looking west southwest down Camera Road. - Edwards Air Force Base, South Base Sled Track, Edwards Air Force Base, North of Avenue B, between 100th & 140th Streets East, Lancaster, Los Angeles County, CA

  18. Forest bioenergy or forest carbon? Assessing trade-offs in greenhouse gas mitigation with wood-based fuels.

    PubMed

    McKechnie, Jon; Colombo, Steve; Chen, Jiaxin; Mabee, Warren; MacLean, Heather L

    2011-01-15

    The potential of forest-based bioenergy to reduce greenhouse gas (GHG) emissions when displacing fossil-based energy must be balanced with forest carbon implications related to biomass harvest. We integrate life cycle assessment (LCA) and forest carbon analysis to assess total GHG emissions of forest bioenergy over time. Application of the method to case studies of wood pellet and ethanol production from forest biomass reveals a substantial reduction in forest carbon due to bioenergy production. For all cases, harvest-related forest carbon reductions and associated GHG emissions initially exceed avoided fossil fuel-related emissions, temporarily increasing overall emissions. In the long term, electricity generation from pellets reduces overall emissions relative to coal, although forest carbon losses delay net GHG mitigation by 16-38 years, depending on biomass source (harvest residues/standing trees). Ethanol produced from standing trees increases overall emissions throughout 100 years of continuous production: ethanol from residues achieves reductions after a 74 year delay. Forest carbon more significantly affects bioenergy emissions when biomass is sourced from standing trees compared to residues and when less GHG-intensive fuels are displaced. In all cases, forest carbon dynamics are significant. Although study results are not generalizable to all forests, we suggest the integrated LCA/forest carbon approach be undertaken for bioenergy studies. PMID:21142063

  19. Spatio-temporal changes in biomass carbon sinks in China's forests from 1977 to 2008.

    PubMed

    Guo, Zhaodi; Hu, Huifeng; Li, Pin; Li, Nuyun; Fang, Jingyun

    2013-07-01

    Forests play a leading role in regional and global carbon (C) cycles. Detailed assessment of the temporal and spatial changes in C sinks/sources of China's forests is critical to the estimation of the national C budget and can help to constitute sustainable forest management policies for climate change. In this study, we explored the spatio-temporal changes in forest biomass C stocks in China between 1977 and 2008, using six periods of the national forest inventory data. According to the definition of the forest inventory, China's forest was categorized into three groups: forest stand, economic forest, and bamboo forest. We estimated forest biomass C stocks for each inventory period by using continuous biomass expansion factor (BEF) method for forest stands, and the mean biomass density method for economic and bamboo forests. As a result, China's forests have accumulated biomass C (i.e., biomass C sink) of 1896 Tg (1 Tg=10(12) g) during the study period, with 1710, 108 and 78 Tg C in forest stands, and economic and bamboo forests, respectively. Annual forest biomass C sink was 70.2 Tg C a(-1), offsetting 7.8% of the contemporary fossil CO2 emissions in the country. The results also showed that planted forests have functioned as a persistent C sink, sequestrating 818 Tg C and accounting for 47.8% of total C sink in forest stands, and that the old-, mid- and young-aged forests have sequestrated 930, 391 and 388 Tg C from 1977 to 2008. Our results suggest that China's forests have a big potential as biomass C sink in the future because of its large area of planted forests with young-aged growth and low C density. PMID:23722235

  20. Bryophyte species associations with coarse woody debris and stand ages in Oregon

    USGS Publications Warehouse

    Rambo, T.; Muir, Patricia S.

    1998-01-01

    We quantified the relationships of 93 forest floor bryophyte species, including epiphytes from incorporated litterfall, to substrate and stand age in Pseudotsuga menziesii-Tsuga heterophylla stands at two sites in western Oregon. We used the method of Dufr??ne and Legendre that combines a species' relative abundance and relative frequency, to calculate that species' importance in relation to environmental variables. The resulting 'indicator value' describes a species' reliability for indicating the given environmental parameter. Thirty-nine species were indicative of either humus, a decay class of coarse woody debris, or stand age. Bryophyte community composition changed along the continuum of coarse woody debris decomposition from recently fallen trees with intact bark to forest floor humus. Richness of forest floor bryophytes will be enhanced when a full range of coarse woody debris decay classes is present. A suite of bryophytes indicated old-growth forest. These were mainly either epiphytes associated with older conifers or liverworts associated with coarse woody debris. Hardwood-associated epiphytes mainly indicated young stands. Mature conifers, hardwoods, and coarse woody debris are biological legacies that can be protected when thinning managed stands to foster habitat complexity and biodiversity, consistent with an ecosystem approach to forest management.