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Sample records for blume forest stand

  1. 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.

  2. 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

  3. Growth and photosynthesis of tropical forest tree seedlings (Bischofia javanica Blume) as influenced by a change in light availability.

    PubMed

    Kamaluddin, M; Grace, J

    1993-09-01

    Acclimation in seedlings of Bischofia javanica Blume, which are commonly found in canopy gaps in the moist forests of tropical Asia, to a change in light availability was examined in a controlled environment simulating forest shade and daylight. Seedlings were grown in a high (1000 micro mol m(-2) s(-1); red/far-red, 1.45) or low (40 micro mol m(-2) s(-1); red/far-red, 0.10) light regime and then transferred to the contrasting light environment for nine weeks. Control seedlings were maintained in the same light regime throughout the study. The availability of light influenced relative growth rate through morphological and physiological adjustments. Transferred seedlings retained the leaves that had been developed before transfer, and no leaf-shedding was observed till the end of the experiment. Leaves formed in the new light regime were physiologically and morphologically identical to those of the corresponding controls. High-light seedlings transferred to low light displayed significantly lower relative growth rate than the low-light controls because of a lower leaf area ratio carried over from the previous high-light environment. A reverse pattern of response with respect to relative growth rate was observed for the low-light seedlings transferred to high light compared to the high-light controls. The higher relative growth rate in the low-light seedlings transferred to high light was the result of higher net assimilation rate and higher leaf area ratio. The higher leaf area ratio in the low-light seedlings transferred to high light was the consequence of the effects of previous environment, and the relatively lower net assimilation rate in the high-light control seedlings was, at least partly, due to the effects of self-shading rather than to the photosynthetic capacity of the leaves. The results suggest that the species has a wide acclimation potential to a change in light availability that might occur in nature following gap creation or canopy closure.

  4. 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.

  5. Talking with Judy Blume

    ERIC Educational Resources Information Center

    Freeman, Judy

    2005-01-01

    The believable voices of Judy Blume's characters--such as the troublemaking Fudge from "Tales of a Fourth Grade Nothing" and freckle-less Andrew from "Freckle Juice"--have charmed readers since Blume published her first book, "The One in the Middle Is the Green Kangaroo," in 1969. This article presents an interview with author Judy Blume. In this…

  6. 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.

  7. The role of stand history in assessing forest impacts

    USGS Publications Warehouse

    Dale, V.H.; Doyle, T.W.

    1987-01-01

    Air pollution, harvesting practices, and natural disturbances can affect the growth of trees and forest development. To make predictions about anthropogenic impacts on forests, we need to understand how these factors affect tree growth. In this study the effect of disturbance history on tree growth and stand structure was examined by using a computer model of forest development. The model was run under the climatic conditions of east Tennessee, USA, and the results compared to stand structure and tree growth data from a yellow poplar-white oak forest. Basal area growth and forest biomass were more accurately projected when rough approximations of the thinning and fire history typical of the measured plots were included in the simulation model. Stand history can influence tree growth rates and forest structure and should be included in any attempt to assess forest impacts.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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…

  13. 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.

  14. [Carbon storage of forest stands in Shandong Province estimated by forestry inventory data].

    PubMed

    Li, Shi-Mei; Yang, Chuan-Qiang; Wang, Hong-Nian; Ge, Li-Qiang

    2014-08-01

    Based on the 7th forestry inventory data of Shandong Province, this paper estimated the carbon storage and carbon density of forest stands, and analyzed their distribution characteristics according to dominant tree species, age groups and forest category using the volume-derived biomass method and average-biomass method. In 2007, the total carbon storage of the forest stands was 25. 27 Tg, of which the coniferous forests, mixed conifer broad-leaved forests, and broad-leaved forests accounted for 8.6%, 2.0% and 89.4%, respectively. The carbon storage of forest age groups followed the sequence of young forests > middle-aged forests > mature forests > near-mature forests > over-mature forests. The carbon storage of young forests and middle-aged forests accounted for 69.3% of the total carbon storage. Timber forest, non-timber product forest and protection forests accounted for 37.1%, 36.3% and 24.8% of the total carbon storage, respectively. The average carbon density of forest stands in Shandong Province was 10.59 t x hm(-2), which was lower than the national average level. This phenomenon was attributed to the imperfect structure of forest types and age groups, i. e., the notably higher percentage of timber forests and non-timber product forest and the excessively higher percentage of young forests and middle-aged forest than mature forests.

  15. 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.

  16. 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

  17. 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.

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

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

    PubMed

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

    2014-08-01

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

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

    USGS Publications Warehouse

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

    2014-01-01

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

  8. 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.

  9. 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.

  10. 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.

  11. Comparison of Al speciation and other soil characteristics between meadow, young forest and old forest stands.

    PubMed

    Dlouhá, Sárka; Borůvka, Lubos; Pavlů, Lenka; Tejnecký, Václav; Drábek, Ondrej

    2009-11-01

    The aim of this paper is to describe the influence of spruce (Picea abies) afforestation on soil chemical properties, especially on soil acidity and aluminium (Al) mobilization and speciation in soil. For our study we used a unique set of three adjacent plots, including a meadow and two spruce forest stands of different age, in otherwise comparable conditions. The plots were located in the region of Giant Mountains, north-eastern Czech Republic. In general, pH values decreased and Al concentrations increased significantly after afforestation. Speciation of KCl-extractable and water-soluble Al in soil samples was done by means of HPLC/IC method. The concentrations of Al(X)(1+) and Al(Y)(2+) forms (in both extracts) are higher in humic and organically enriched (Bhs) horizons. The highest concentration of Al(3+) in both extracts is in the B horizons of old forest. Generally, in all studied stands majority of Al in aqueous extract is in the Al(X)(1+) form, which indicates that a large amount of mobile Al is bound in organic complexes. It suggests that actual toxicity is rather low. On the other hand, we have proved that majority of KCl-extractable Al exists in Al(3+) form. Thus we can conclude that disturbance of existing equilibrium may cause massive release of highly toxic Al(3+) from soil sorption complex to the soil solution, and consequently it can endanger the whole ecosystem. Moreover, continuous soil acidification accelerated by anthropogenic factors leading to Al mobilization represents a chemical time bomb. PMID:19748129

  12. 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

  13. Bark Beetles as Significant Forest Disturbances: Estimating Susceptibility Based On Stand Structure

    NASA Astrophysics Data System (ADS)

    Hicke, J. A.; Jenkins, J. C.

    2007-12-01

    In the western United States, bark beetle outbreaks affect millions of hectares of forests. These disturbances have multiple effects on ecosystems, including modifications to biogeochemical cycles, interactions with fire, and changes in land cover type and species composition. In recent years, extensive outbreaks have occurred in multiple forest ecosystems in the West, thought to be caused by climate variability and stand structure. In this study, we focus on epidemics of mountain pine beetle. We used USDA Forest Service inventories and a model to estimate lodgepole pine susceptibility to mountain pine beetle attack in the West. The model considers stand age, stem density, and percentage of large lodgepole pine to estimate stand susceptibility. Over 150,000 trees in 4454 plots across the western United States were used to compute susceptibility at the plot scale as well as map susceptibility at the county scale. We found that regional susceptibility was high (estimated potential of losses of 34% of stand basal area) for 2.8 Mha, or 46%, of lodgepole pine forests. The highest susceptibility occurred in the Rocky Mountains, with lower susceptibility in coastal states. This study reveals that a substantial fraction of lodgepole pine forest could be subjected to bark beetle outbreaks under current climate conditions. Because climate and weather affect beetle populations, projected future warming will influence outbreak regimes. Thus, forest ecosystems in the West may experience more frequent, extensive, and/or severe disturbances than in recent decades due to current stand structure, and these disturbances may be intensified under climate change.

  14. Variation in carbon storage and its distribution by stand age and forest type in boreal and temperate forests in northeastern China.

    PubMed

    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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. Hawaiian native forest conserves water relative to timber plantation: species and stand traits influence water use.

    PubMed

    Kagawa, Aurora; Sack, Lawren; Duarte, Ka'eo; James, Shelley

    2009-09-01

    Tropical forests are becoming increasingly alien-dominated through the establishment of timber plantations and secondary forests. Despite widespread recognition that afforestation results in increased evapotranspiration and lower catchment yields, little is known of the impacts of timber plantations on water balance relative to native forest. Native forest trees have been claimed to use water conservatively and enhance groundwater recharge relative to faster-growing alien species, and this argument should motivate native forest preservation and restoration. However, data have been available primarily for leaf-level gas exchange rather than for whole-plant and stand levels. We measured sap flow of dominant tree and tree fern species over eight weeks in native Metrosideros polymorpha forest and adjacent alien timber plantations on the island of Hawai'i and estimated total stand transpiration. Metrosideros polymorpha had the lowest values of sap flux density and whole-tree water use (200 kg m(-2) sapwood d(-1), or 8 kg/d for trees of 35 cm mean diameter at breast height, D), substantially less than timber species Eucalyptus saligna or Fraxinus uhdei (33 and 34 kg/d for trees of 73 and 30 cm mean D, respectively). At the stand level, E. saligna and F. uhdei trees had three- and ninefold higher water use, respectively, than native M. polymorpha trees. Understory Cibotium tree ferns were most abundant in M. polymorpha-dominated forest where they accounted for 70% of water use. Overall, F. uhdei plantation had the highest water use at 1.8 mm/d, more than twice that of either E. saligna plantation or M. polymorpha forest. Forest water use was influenced by species composition, stem density, tree size, sapwood allocation, and understory contributions. Transpiration varied strongly among forest types even within the same wet tropical climate, and in this case, native forest had strikingly conservative water use. Comparisons of vegetation cover in water use should provide

  2. Characterizing forest stands with multi-incidence angle and multi-polarized SAR data

    NASA Technical Reports Server (NTRS)

    Hoffer, R. M.; Lozano-Garcia, D. F.; Gillespie, D. D.

    1987-01-01

    The potential for using HH-polarized L-band SAR data obtained at different incidence angles from satellite altitudes to identify and map different forest cover types and stand density classes is studied. Reasonably accurate results are obtained if the speckle characteristics of the data are suppressed by low-pass spatial filters and a contextual classification algorithm. Multipolarized L-band SAR data obtained from aircraft altitudes over the same test site are also analyzed to assess the relationships between polarization and forest stand characteristics. It is found that incidence angle controls, to a very large extent, the characteristics of the data and the type of information that can be obtained from L-band, HH-polarized satellite SAR data. Cross-polarization of L-band SAR data enhances and differentiates various forest stand characteristics which cannot be defined using only the like-polarized data, and vice-versa.

  3. 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%).

  4. 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.

  5. 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.

  6. 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

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

    PubMed

    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.

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

    PubMed

    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

  9. 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

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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

  15. 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

  16. 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%...

  17. 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...

  18. 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.

  19. 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.

  20. Relationship between basal soil respiration rate, tree stand and soil characteristics in boreal forests.

    PubMed

    Vanhala, P; Tamminen, P; Fritze, H

    2005-02-01

    Soil respiration is considered to represent the overall microbial activity reflecting mineralisation of organic matter in soil. It is the most commonly used biological variable in soil studies. In long-term monitoring of forested areas, there is a need for reference values for soil microbiological variables in different forest ecosystems. In this study we describe the relationship between soil respiration rate, tree stand and humus chemical characteristics of boreal coniferous forests stands. Soil respiration rate was higher in pine dominated than in spruce dominated study sites when the result was calculated on dry matter bases. However, when calculated on area bases, the result was opposite and no difference was found when the soil respiration rate was calculated on organic carbon bases. Irrespective of the main tree species, the soil respiration rate was equal in different development classes but not equal in soil fertility classes, i.e. within forest site types based on differences in ground vegetation. Respiration rates were clearly higher in mesic sites when calculated on dry matter, C(org) or area bases. However, soil respiration rate did not correlate with soil chemical variables indicating site fertility. Soil respiration rate on dry matter basis was at a lower level in the south and on more fertile sites, and on the other hand at a higher level in older stands and on sites with a thicker organic layer. PMID:15736877

  1. 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

  2. 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

  3. Variability in Albedo Associated with Fire-Mediated Controls on Stand Density in Siberian Larch Forests

    NASA Astrophysics Data System (ADS)

    Loranty, M. M.; Fullmer, J.; Nguyen, C. L.; Alexander, H. D.; Natali, S.; Bunn, A. G.; Davydov, S. P.; Goetz, S. J.; Mack, M. C.

    2015-12-01

    Fire is an integral component of boreal forests, and exerts strong control over ecosystem structure and function. The frequency and spatial extent of fire controls the age-class distribution of forests on the landscape. In addition, recent evidence from North American boreal forests has show that fire severity influences post-fire succession via impacts on seedling recruitment that manifest in mature ecosystems dominated by either deciduous or coniferous tree species. The effects of fire on ecosystem structure have important climate feedback implications; changes in forest density or leaf habit can influence surface net radiation by altering the snow-masking effects of vegetation. Although Siberian larch forests occupy a more than 2.8 million km2 of the boreal biome, and are the most prevalent forests in Russia, the influence of fire severity on succession and associated surface energy dynamics are less well understood in comparison to North American boreal forests. There is evidence suggesting that increased fire severity may lead to higher density of post-fire regrowth, but the influence of stand density on surface energy dynamics remains poorly quantified. Here, we quantify the effects of stand density on albedo across the Kolyma River basin using satellite-derived albedo and fire history in conjunction with maps and field observations of ecosystem structure. During snow-free periods albedo varies little with stand density. During periods of snow cover we find consistent negative correlations between multiple metrics of canopy cover and albedo. Albedo decreased with fire recovery over the forty-year fire record for the study area. However, the range of albedo observed within individual fire scars was similar to the magnitude of albedo recovery during the study period. This result indicates the importance of variability in post-fire regrowth within individual fire scars, potentially associated with fire severity, for understanding fire effects on surface energy

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

    PubMed

    Jacob, Mascha; Viedenz, Karin; Polle, Andrea; Thomas, Frank M

    2010-12-01

    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 Acer platanoides) 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.

  5. 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

  6. 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.

  7. 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

  8. Fire-mediated pathways of stand development in Douglas-fir/ western hemlock forests of the Pacific Northwest, USA.

    PubMed

    Tepley, Alan J; Swanson, Frederick J; Spies, Thomas A

    2013-08-01

    Forests dominated by Douglas-fir and western hemlock in the Pacific Northwest of the United States have strongly influenced concepts and policy concerning old-growth forest conservation. Despite the attention to their old-growth characteristics, a tendency remains to view their disturbance ecology in relatively simple terms, emphasizing infrequent, stand-replacing (SR) fire and an associated linear pathway toward development of those old-growth characteristics. This study uses forest stand- and age-structure data from 124 stands in the central western Cascades of Oregon to construct a conceptual model of stand development under the mixed-severity fire regime that has operated extensively in this region. Hierarchical clustering of variables describing the age distributions of shade-intolerant and shade-tolerant species identified six groups, representing different influences of fire frequency and severity on stand development. Douglas-fir trees > 400 years old were found in 84% of stands, yet only 18% of these stands (15% overall) lack evidence of fire since the establishment of these old trees, whereas 73% of all stands show evidence of at least one non-stand-replacing (NSR) fire. Differences in fire frequency and severity have contributed to multiple development pathways and associated variation in contemporary stand structure and the successional roles of the major tree species. Shade-intolerant species form a single cohort following SR fire, or up to four cohorts per stand in response to recurring NSR fires that left living trees at densities up to 45 trees/ha. Where the surviving trees persist at densities of 60-65 trees/ha, the postfire cohort is composed only of shade-tolerant species. This study reveals that fire history and the development of old-growth forests in this region are more complex than characterized in current stand-development models, with important implications for maintaining existing old-growth forests and restoring stands subject to timber

  9. Stand structural diversity rather than species diversity enhances aboveground carbon storage in secondary subtropical forests in Eastern China

    NASA Astrophysics Data System (ADS)

    Ali, Arshad; Yan, En-Rong; Chen, Han Y. H.; Chang, Scott X.; Zhao, Yan-Tao; Yang, Xiao-Dong; Xu, Ming-Shan

    2016-08-01

    Stand structural diversity, typically characterized by variances in tree diameter at breast height (DBH) and total height, plays a critical role in influencing aboveground carbon (C) storage. However, few studies have considered the multivariate relationships of aboveground C storage with stand age, stand structural diversity, and species diversity in natural forests. In this study, aboveground C storage, stand age, tree species, DBH and height diversity indices, were determined across 80 subtropical forest plots in Eastern China. We employed structural equation modelling (SEM) to test for the direct and indirect effects of stand structural diversity, species diversity, and stand age on aboveground C storage. The three final SEMs with different directions for the path between species diversity and stand structural diversity had a similar goodness of fit to the data. They accounted for 82 % of the variation in aboveground C storage, 55-59 % of the variation in stand structural diversity, and 0.1 to 9 % of the variation in species diversity. Stand age demonstrated strong positive total effects, including a positive direct effect (β = 0.41), and a positive indirect effect via stand structural diversity (β = 0.41) on aboveground C storage. Stand structural diversity had a positive direct effect on aboveground C storage (β = 0.56), whereas there was little total effect of species diversity as it had a negative direct association with, but had a positive indirect effect, via stand structural diversity, on aboveground C storage. The negligible total effect of species diversity on aboveground C storage in the forests under study may have been attributable to competitive exclusion with high aboveground biomass, or a historical logging preference for productive species. Our analyses suggested that stand structural diversity was a major determinant for variations in aboveground C storage in the secondary subtropical forests in Eastern China. Hence, maintaining tree DBH and

  10. Bacterial, archaeal and eukaryal community structures throughout soil horizons of harvested and naturally disturbed forest stands.

    PubMed

    Hartmann, Martin; Lee, Sangwon; Hallam, Steven J; Mohn, William W

    2009-12-01

    Disturbances caused by timber harvesting have critical long-term effects on the forest soil microbiota and alter fundamental ecosystem services provided by these communities. This study assessed the effects of organic matter removal and soil compaction on microbial community structures in different soil horizons 13 years after timber harvesting at the long-term soil productivity site at Skulow Lake, British Columbia. A harvested stand was compared with an unmanaged forest stand. Ribosomal intergenic spacer profiles of bacteria, archaea and eukarya indicated significantly different community structures in the upper three soil horizons of the two stands, with differences decreasing with depth. Large-scale sequencing of the ribosomal intergenic spacers coupled to small-subunit ribosomal RNA genes allowed taxonomic identification of major microbial phylotypes affected by harvesting or varying among soil horizons. Actinobacteria and Gemmatimonadetes were the predominant phylotypes in the bacterial profiles, with the relative abundance of these groups highest in the unmanaged stand, particularly in the deeper soil horizons. Predominant eukaryal phylotypes were mainly assigned to known mycorrhizal and saprotrophic species of Basidiomycetes and Ascomycetes. Harvesting affected Basidiomycetes to a minor degree but had stronger effects on some Ascomycetes. Archaeal profiles had low diversity with only a few predominant crenarchaeal phylotypes whose abundance appeared to increase with depth. Detection of these effects 13 years after harvesting may indicate a long-term change in processes mediated by the microbial community with important consequences for forest productivity. These effects warrant more comprehensive investigation of the effects of harvesting on the structure of forest soil microbial communities and the functional consequences. PMID:19659501

  11. 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

  12. Changes of the spruce forest stand aerodynamic properties during ten growing seasons

    NASA Astrophysics Data System (ADS)

    Hurtalova, T.; Matejka, F.; Janous, D.; Czerny, R.

    2009-04-01

    Objective of this study was to quantify the influence of a young spruce forest stand on airflow and its aerodynamic characteristics during ten growing seasons. With this aim the wind speed profiles measured in and above investigated spruce stand during growing seasons, from May to October, 1998-2007 were analysed. Experimental site is situated on a mild slope with SW orientation in the locality Bílý Kříž (49o30'17'' N, 18o32'28'' E, 898-908 m a.s.l.), which is in the highest part of the Moravian-Silesian Beskydy Mts, Czech Republic. The experimental site consisting of two plots Fd and Fs with different tree density is created by the monoculture of young Norway spruce stand (Picea abies L., Karst) with age of 17 years in 1998. Each of these plots has the area of 2500 m2, density of 2600 trees/ha in Fd plot and 2400 trees/ha in Fs plot in 1998, and gradually 1652 trees/ha (Fd) and 1428 trees/ha (Fs) in 2007. The aerodynamic characteristics can be described by the roughness length (z0) and the zero plane displacement (d). The presented study aims to analyse the changes in d and z0 values for a young spruce forest stand during ten consecutive growing seasons, and to relate the aerodynamic properties of an air layer affected by this stand to its growth parameters. It is known, that the local terrain and structure of forest stand influenced the direction and power of the airflow, as well as the structure of vertical wind speed profiles. From the wind speed profile analysis it follows, that the investigated spruce stand was in an aerodynamic unsteady state and then d and z0 values vary also with the wind speed. During investigated seasons the mean seasonal z0 values ranged between 0.48 m and 1.32 m in Fd and the corresponding values in Fs plot varied between 0.41 m and 1.36 m. The mean seasonal d values varied between 0.60h and 0.76h in Fd, and 61h and 0.76h in Fs, h is mean stand height.

  13. Leaf distribution in large trees and stands of the floodplain forest in southern Moravia.

    PubMed

    Cermák, Jan

    1998-11-01

    Vertical distributions of leaf dry mass (M(d)) and leaf area (A(f)) were related to relative irradiance (I(r); I(r) above the stand = 1) in closed-canopy, old-growth stands of the floodplain forest in southern Moravia composed largely of Quercus, Fraxinus and Tilia species. Foliage area and mass at any given canopy height were converted to solar equivalent leaf area (A(s)) and mass (M(s)) by multiplying actual values at a given level in the canopy by the relative irradiance at that position. Stand leaf area index (LAI) was 5 (7 including shrub and herb layer), and solar equivalent parameters reached about 25% of that amount. In all species, vertical profiles of both relative irradiance and leaf dry mass to area ratio (LMA) were sigmoidal and the two variables were linearly related. The dominant, upper canopy species had a larger proportion of solar equivalent foliage than suppressed understory species. For individual trees of all species, the upper canopy had a larger proportion of solar equivalent foliage than the lower canopy. Light compensation points at both the leaf and whole-tree level were defined according to leaf or tree position, size and structure. I conclude that optimization of A(s) for forest stands may be used as a basis for determining thinning schedules and evaluating tree survival after damage to tree crowns by various factors.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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

  19. Stand-replacing wildfires increase nitrification for decades in southwestern ponderosa pine forests.

    PubMed

    Kurth, Valerie J; Hart, Stephen C; Ross, Christopher S; Kaye, Jason P; Fulé, Peter Z

    2014-05-01

    Stand-replacing wildfires are a novel disturbance within ponderosa pine (Pinus ponderosa) forests of the southwestern United States, and they can convert forests to grasslands or shrublands for decades. While most research shows that soil inorganic N pools and fluxes return to pre-fire levels within a few years, we wondered if vegetation conversion (ponderosa pine to bunchgrass) following stand-replacing fires might be accompanied by a long-term shift in N cycling processes. Using a 34-year stand-replacing wildfire chronosequence with paired, adjacent unburned patches, we examined the long-term dynamics of net and gross nitrogen (N) transformations. We hypothesized that N availability in burned patches would become more similar to those in unburned patches over time after fire as these areas become re-vegetated. Burned patches had higher net and gross nitrification rates than unburned patches (P < 0.01 for both), and nitrification accounted for a greater proportion of N mineralization in burned patches for both net (P < 0.01) and gross (P < 0.04) N transformation measurements. However, trends with time-after-fire were not observed for any other variables. Our findings contrast with previous work, which suggested that high nitrification rates are a short-term response to disturbance. Furthermore, high nitrification rates at our site were not simply correlated with the presence of herbaceous vegetation. Instead, we suggest that stand-replacing wildfire triggers a shift in N cycling that is maintained for at least three decades by various factors, including a shift from a woody to an herbaceous ecosystem and the presence of fire-deposited charcoal.

  20. 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

  1. Standing crop and aboveground biomass partitioning of a dwarf mangrove forest in Taylor River Slough, Florida

    USGS Publications Warehouse

    Coronado-Molina, C.; Day, J.W.; Reyes, E.; Perez, B.C.

    2004-01-01

    The structure and standing crop biomass of a dwarf mangrove forest, located in the salinity transition zone ofTaylor River Slough in the Everglades National Park, were studied. Although the four mangrove species reported for Florida occurred at the study site, dwarf Rhizophora mangle trees dominated the forest. The structural characteristics of the mangrove forest were relatively simple: tree height varied from 0.9 to 1.2 meters, and tree density ranged from 7062 to 23 778 stems haa??1. An allometric relationship was developed to estimate leaf, branch, prop root, and total aboveground biomass of dwarf Rhizophora mangle trees. Total aboveground biomass and their components were best estimated as a power function of the crown area times number of prop roots as an independent variable (Y = B ?? Xa??0.5083). The allometric equation for each tree component was highly significant (p<0.0001), with all r2 values greater than 0.90. The allometric relationship was used to estimate total aboveground biomass that ranged from 7.9 to 23.2 ton haa??1. Rhizophora mangle contributed 85% of total standing crop biomass. Conocarpus erectus, Laguncularia racemosa, and Avicennia germinans contributed the remaining biomass. Average aboveground biomass allocation was 69% for prop roots, 25% for stem and branches, and 6% for leaves. This aboveground biomass partitioning pattern, which gives a major role to prop roots that have the potential to produce an extensive root system, may be an important biological strategy in response to low phosphorus availability and relatively reduced soils that characterize mangrove forests in South Florida.

  2. 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.

  3. 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.

  4. 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

  5. Carbon stock evaluation from topsoil of forest stands in NE Italy.

    PubMed

    Faggian, V; Bini, C; Zilioli, D M

    2012-04-01

    Gas emissions from anthropic activities, particularly CO2, are responsible for global warming. Soil is a major carbon sink on a planetary level, thereby contributing to mitigate greenhouse effect. In the present work, the objectives were: 1) to evaluate the topsoil carbon stock of different forest stands in NE Italy, and 2) to outline the relationships among humus forms, soil organic matter dynamics, and actual carbon stock under different vegetation coverage, with reference to climate change. Five forest stands and the related topsoils, were selected in the Dolomites area. The humus forms were examined in the field and samples were carried to the lab for further physical-chemical analyses. The carbon stock for each soil was calculated by means of pedotransfer functions. The less developed humus forms, as the Dysmull and the Hemimoder, presented the highest carbon storage capacity (168 t/y and 129 t/y), followed by Lithoamphimus (123 t/y) and Eu-amphimus (96 t/y), and by Oligomull (86 t/y). Organic horizons proved to recover 36% of the total carbon stocked along the soil profile, and this points to humus layers as a fundamental tool in carbon stock evaluation. Positive correlations between elevation, humus forms and soil carbon pools were found. PMID:22567721

  6. 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

  7. 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.

  8. 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

  9. 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.

  10. Forests may need centuries to recover their original productivity after continuous intensive management: an example from Douglas-fir stands.

    PubMed

    Blanco, Juan A

    2012-10-15

    How long would it take for forests to recover their original productivity following continuous intensive management if they are left untouched? This issue was explored using the model FORECAST, calibrated and validated for coastal Douglas-fir stands on Vancouver Island (western Canada). Three types of forest management (production of timber, pulp, and biomass) were simulated, being different in utilization level and rotation length (stem-only and 75-year rotation for timber production, whole-tree and 30-year rotation for pulp/fiber, and whole-tree and 15-year rotations for biomass production). Management was simulated for 150 years, followed by several cycles of natural growth without management ending with a stand-replacing windstorm with a return time of 200 years. Productivity-related ecological variables in previously managed stands were compared to natural forests. Stands developed after management for timber would quickly reach values similar to non-managed forests for tree and understory total biomass, stored carbon, available nitrogen and soil organic matter (SOM). However, intensive management regimes designed for fiber and biomass production would cause a decrease in SOM and nutrient availability, increasing understory biomass. As a consequence, stands recovering from intensive management would need at least two stand-replacing events (400 years) to reach a productivity status similar to non-managed stands. Stands developed after management for biomass would take much longer, up to 600 or 800 years to recover similar values of SOM and understory biomass, respectively. Current fertilization prescriptions will likely be not enough to stop a quick drop in forest productivity associated with intensive management. Intensifying forest management to achieve short-term objectives could produce a reduction of stand productivity that would influence tree growth for very long time (up to several centuries), if such management is continuously implemented at the same

  11. Bark beetle effects on fuel profiles across a range of stand structures in Douglas-fir forests of Greater Yellowstone.

    PubMed

    Donato, Daniel C; Harvey, Brian J; Romme, William H; Simard, Martin; Turner, Monica G

    2013-01-01

    Consequences of bark beetle outbreaks for forest wildfire potential are receiving heightened attention, but little research has considered ecosystems with mixed-severity fire regimes. Such forests are widespread, variable in stand structure, and often fuel limited, suggesting that beetle outbreaks could substantially alter fire potentials. We studied canopy and surface fuels in interior Douglas-fir (Pseudotsuga menziesii v. glauca) forests in Greater Yellowstone, Wyoming, USA, to determine how fuel characteristics varied with time since outbreak of the Douglas-fir beetle (Dendroctonus pseudotsugae). We sampled five stands in each of four outbreak stages, validated for pre-outbreak similarity: green (undisturbed), red (1-3 yr), gray (4-14 yr), and silver (25-30 yr). General linear models were used to compare variation in fuel profiles associated with outbreak to variation associated with the range of stand structures (dense mesic forest to open xeric parkland) characteristic of interior Douglas-fir forest. Beetle outbreak killed 38-83% of basal area within stands, generating a mix of live trees and snags over several years. Canopy fuel load and bulk density began declining in the red stage via needle drop and decreased by approximately 50% by the silver stage. The dead portion of available canopy fuels peaked in the red stage at 41%. After accounting for background variation, there was little effect of beetle outbreak on surface fuels, with differences mainly in herbaceous biomass (50% greater in red stands) and coarse woody fuels (doubled in silver stands). Within-stand spatial heterogeneity of fuels increased with time since outbreak, and surface-to-crown continuity decreased and remained low because of slow/sparse regeneration. Collectively, results suggest reduced fire potentials in post-outbreak stands, particularly for crown fire after the red stage, although abundant coarse fuels in silver stands may increase burn residence time and heat release. Outbreak

  12. Response of old-growth conifers to reduction in stand density in western Oregon forests

    USGS Publications Warehouse

    Latham, P.; Tappeiner, J. C.

    2002-01-01

    The positive growth response of healthy young trees to density reduction is well known. In contrast, large old trees are usually thought to be intrinsically limited in their ability to respond to increased growing space; therefore, density reduction is seldom used in stands of old-growth trees. We tested the null hypothesis that old-growth trees are incapable of responding with increased growth following density reduction. The diameter growth response of 271 Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), ponderosa pine (Pinus ponderosa Dougl. ex Laws) and sugar pine (Pinus lambertiana Dougl.) trees ranging in age from 158 to 650 years was examined 20 to 50 years after density reduction. Density reduction involved either light thinning with removal of less vigorous trees, or shelterwood treatments in which overstory trees were not removed. Ratios of basal area growth after treatment to basal area growth before treatment, and several other measures of growth, all indicated that the old trees sometimes benefited and were not harmed by density reduction. Growth increased by 10% or more for 68% of the trees in treated stands, and nearly 30% of trees increased growth by over 50%. This growth response persisted for at least 20 years. During this 20-year period, only three trees in treated stands (1.5%) exhibited a rapid decrease in growth, whereas growth decreased in 64% of trees in untreated stands. The length of time before a growth response to density reduction occurred varied from 5 to 25 years, with the greatest growth response often occurring 20 to 25 years after treatment. These results have important implications both for the basic biology of aging in woody plants as well as for silvicultural practices in forests with old-growth trees.

  13. 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

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. Assessment of tropical forest stand characteristics with multipolarization SAR data acquired over a mountainous region in Costa Rica

    NASA Technical Reports Server (NTRS)

    Wu, Shih-Tseng

    1990-01-01

    A digital terrain elevation data set was coregistered with radar data for assessing tropical forest stand characteristics. Both raw and topographically corrected L-band polarimetric radar data acquired over the tropical forests of Costa Rica were analyzed and correlated with field-collected tree parameter data to study the stand characteristics. The results of analyses using 18 out of 81 plots for sites A and B indicated that per-plot bole volume and tree volume are related to SAR data, particularly at site A. The topographically corrected SAR data appear to produce the same findings as those of uncorrected data.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. Relationships between net primary productivity and stand age for several forest types and their influence on China's carbon balance.

    PubMed

    Wang, Shaoqiang; Zhou, Lei; Chen, Jingming; Ju, Weimin; Feng, Xianfeng; Wu, Weixing

    2011-06-01

    Affected by natural and anthropogenic disturbances such as forest fires, insect-induced mortality and harvesting, forest stand age plays an important role in determining the distribution of carbon pools and fluxes in a variety of forest ecosystems. An improved understanding of the relationship between net primary productivity (NPP) and stand age (i.e., age-related increase and decline in forest productivity) is essential for the simulation and prediction of the global carbon cycle at annual, decadal, centurial, or even longer temporal scales. In this paper, we developed functions describing the relationship between national mean NPP and stand age using stand age information derived from forest inventory data and NPP simulated by the BEPS (Boreal Ecosystem Productivity Simulator) model in 2001. Due to differences in ecobiophysical characteristics of different forest types, NPP-age equations were developed for five typical forest ecosystems in China (deciduous needleleaf forest (DNF), evergreen needleleaf forest in tropic and subtropical zones (ENF-S), deciduous broadleaf forest (DBF), evergreen broadleaf forest (EBF), and mixed broadleaf forest (MBF)). For DNF, ENF-S, EBF, and MBF, changes in NPP with age were well fitted with a common non-linear function, with R(2) values equal to 0.90, 0.75, 0.66, and 0.67, respectively. In contrast, a second order polynomial was best suitable for simulating the change of NPP for DBF, with an R(2) value of 0.79. The timing and magnitude of the maximum NPP varied with forest types. DNF, EBF, and MBF reached the peak NPP at the age of 54, 40, and 32 years, respectively, while the NPP of ENF-S maximizes at the age of 13 years. The highest NPP of DBF appeared at 122 years. NPP was generally lower in older stands with the exception of DBF, and this particular finding runs counter to the paradigm of age-related decline in forest growth. Evaluation based on measurements of NPP and stand age at the plot-level demonstrates the reliability

  4. Relationships between net primary productivity and stand age for several forest types and their influence on China's carbon balance.

    PubMed

    Wang, Shaoqiang; Zhou, Lei; Chen, Jingming; Ju, Weimin; Feng, Xianfeng; Wu, Weixing

    2011-06-01

    Affected by natural and anthropogenic disturbances such as forest fires, insect-induced mortality and harvesting, forest stand age plays an important role in determining the distribution of carbon pools and fluxes in a variety of forest ecosystems. An improved understanding of the relationship between net primary productivity (NPP) and stand age (i.e., age-related increase and decline in forest productivity) is essential for the simulation and prediction of the global carbon cycle at annual, decadal, centurial, or even longer temporal scales. In this paper, we developed functions describing the relationship between national mean NPP and stand age using stand age information derived from forest inventory data and NPP simulated by the BEPS (Boreal Ecosystem Productivity Simulator) model in 2001. Due to differences in ecobiophysical characteristics of different forest types, NPP-age equations were developed for five typical forest ecosystems in China (deciduous needleleaf forest (DNF), evergreen needleleaf forest in tropic and subtropical zones (ENF-S), deciduous broadleaf forest (DBF), evergreen broadleaf forest (EBF), and mixed broadleaf forest (MBF)). For DNF, ENF-S, EBF, and MBF, changes in NPP with age were well fitted with a common non-linear function, with R(2) values equal to 0.90, 0.75, 0.66, and 0.67, respectively. In contrast, a second order polynomial was best suitable for simulating the change of NPP for DBF, with an R(2) value of 0.79. The timing and magnitude of the maximum NPP varied with forest types. DNF, EBF, and MBF reached the peak NPP at the age of 54, 40, and 32 years, respectively, while the NPP of ENF-S maximizes at the age of 13 years. The highest NPP of DBF appeared at 122 years. NPP was generally lower in older stands with the exception of DBF, and this particular finding runs counter to the paradigm of age-related decline in forest growth. Evaluation based on measurements of NPP and stand age at the plot-level demonstrates the reliability

  5. 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

  6. 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

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. Effects of dwarf mistletoe on stand structure of lodgepole pine forests 21-28 years post-mountain pine beetle epidemic in central Oregon.

    PubMed

    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

  13. 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

  14. Effects of dwarf mistletoe on stand structure of lodgepole pine forests 21-28 years post-mountain pine beetle epidemic in central Oregon.

    PubMed

    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

  15. Carbon pools and temporal dynamics along a rotation period in sessile oak dominated high forest and coppice with standards stands

    NASA Astrophysics Data System (ADS)

    Bruckman, V. J.; Yan, S.; Hochbichler, E.; Glatzel, G.

    2012-04-01

    Carbon pools in two Quercus petraea (sessile oak) dominated chronosequences under different forest management (high forest and coppice with standards) were investigated. The objective was to study temporal carbon dynamics, in particular carbon sequestration in the soil and woody biomass production, in common forest management systems in eastern Austria along with stand development. The chronosequence approach was used to substitute time-for-space to enable coverage of a full rotation period in each system. Carbon content was determined in the following compartments: aboveground biomass, litter, soil to a depth of 50 cm, living root biomass and decomposing residues in the mineral soil horizons. Biomass carbon pools, except fine roots and residues, were estimated using species-specific allometric functions. Total carbon pools were on average 143 Mg ha-1 in the high forest stand (HF) and 213 Mg ha-1 in the coppice with standards stand (CS). The mean share of the total organic carbon pool (TOC) which is soil organic carbon (SOC) differs only marginally between HF (43.4%) and CS (42.1%), indicating the dominance of site factors, particularly climate, in controlling this ratio. While there was no significant change in O-layer and SOC stores over stand development, we found clear relationships between living biomass (aboveground and belowground) pools and C:N ratio in topsoil horizons with stand age. SOC pools seem to be very stable and an impact of silvicultural interventions was not detected with the applied method. Rapid decomposition and mineralization of litter, indicated by low O-horizon pools with wide C:N ratios of residual woody debris at the end of the vegetation period, suggests high rates of turnover in this fraction. CS, in contrast to HF benefits from rapid resprouting after coppicing and hence seems less vulnerable to conditions of low rainfall and drying topsoil. Keywords: carbon dynamics; soil carbon; chronosequence; Quercus petraea; coppice; high forest

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. Relationships between stand composition and ectomycorrhizal community structure in boreal mixed-wood forests.

    PubMed

    DeBellis, T; Kernaghan, G; Bradley, R; Widden, P

    2006-07-01

    We investigated the community structure of ectomycorrhizal fungi under varying overstory tree compositions in the southern mixed-wood boreal forest of Quebec. Sampling took place at two locations of differing postfire ages and nine 100-m2 plots were sampled per location. The dominant overstory tree species in the plots were trembling aspen (Populus tremuloides Michx.), white birch (Betula papyrifera Marsh.) or white spruce [Picea glauca (Moench) Voss], and balsam fir [Abies balsamea (L.) Mill.]. Mycorrhizae were analyzed using morphological as well as molecular methods, employing fungal-specific primers to amplify ribosomal DNA for subsequent cloning and sequencing. A total of 1800 mycorrhizal root tips collected from the 18 plots were morphologically classified into 26 morphotypes, with Cenococcum geophilum dominating (36% of root tips). A second set of root tips, selected from the same 18 samples on which the morphological analysis was based, were analyzed using molecular methods. From this analysis, 576 cloned polymerase chain reaction products were screened by restriction fragment length polymorphism analysis and a total of 207 unique types were found. No one type dominated the system and 159 occurred only once. Sequence analysis of the types that occurred more than once revealed that Piloderma sp., Russula sp., Cortinarius sp., and Lactarius sp. were the most common mycorrhizae. The ectomycorrhizal fungal community structure revealed by the rDNA analysis differed from that observed using morphological methods. Canonical correspondence analyses of the sequenced restriction types and % overstory composition indicate that the distributions of ectomycorrhizal fungi are influenced by the relative proportions of host tree species. The distinct fungal assemblages found in the different plots supported by the different combinations of host tree species provides further support for the need to conserve stand diversity in the southern boreal forest.

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

    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

  9. Large sample area and size are needed for forest soil seed bank studies to ensure low discrepancy with standing vegetation.

    PubMed

    Shen, You-xin; Liu, Wei-li; Li, Yu-hui; Guan, Hui-lin

    2014-01-01

    A large number of small-sized samples invariably shows that woody species are absent from forest soil seed banks, leading to a large discrepancy with the seedling bank on the forest floor. We ask: 1) Does this conventional sampling strategy limit the detection of seeds of woody species? 2) Are large sample areas and sample sizes needed for higher recovery of seeds of woody species? We collected 100 samples that were 10 cm (length) × 10 cm (width) × 10 cm (depth), referred to as larger number of small-sized samples (LNSS) in a 1 ha forest plot, and placed them to germinate in a greenhouse, and collected 30 samples that were 1 m × 1 m × 10 cm, referred to as small number of large-sized samples (SNLS) and placed them (10 each) in a nearby secondary forest, shrub land and grass land. Only 15.7% of woody plant species of the forest stand were detected by the 100 LNSS, contrasting with 22.9%, 37.3% and 20.5% woody plant species being detected by SNLS in the secondary forest, shrub land and grassland, respectively. The increased number of species vs. sampled areas confirmed power-law relationships for forest stand, the LNSS and SNLS at all three recipient sites. Our results, although based on one forest, indicate that conventional LNSS did not yield a high percentage of detection for woody species, but SNLS strategy yielded a higher percentage of detection for woody species in the seed bank if samples were exposed to a better field germination environment. A 4 m2 minimum sample area derived from power equations is larger than the sampled area in most studies in the literature. Increased sample size also is needed to obtain an increased sample area if the number of samples is to remain relatively low. PMID:25140738

  10. 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.

  11. [Effects of simulated nitrogen deposition on soil available nitrogen forms and their contents in typical temperate forest stands].

    PubMed

    Chen, Li-xin; Duan, Wen-biao

    2011-08-01

    An indoor experiment was conducted to study the effects of simulated nitrogen deposition on the soil available N in typical temperate forest stands. During the experiment period, nitrogen deposition increased the soil NH4+ -N, NO3- -N, and available N contents, as compared with the control, but the increments differed with stand types, soil layers, nitrogen treatment types, and treatment duration. Mixed forest soil had weaker responses in its available N contents to the nitrogen deposition than broad-leaved forest soil but stronger responses than artificially pure coniferous forest soil, and soil A horizon was more sensitive to nitrogen deposition than soil B horizon. Ammonium nitrogen deposition had larger effects on soil NH4+ -N content, nitrate nitrogen deposition had larger effects on soil NO3- -N content, while mixed ammonium and nitrate nitrogen deposition increased the contents of both soil NH4+ -N and soil NO3- -N, and the increments were higher than those of ammonium nitrogen deposition and nitrate nitrogen deposition, suggesting the additive effects of the mixed ammonium and nitrate nitrogen deposition on the forest soil available N.

  12. Spider assemblages in the overstory, understory, and ground layers of managed stands in the western boreal mixedwood forest of Canada.

    PubMed

    Pinzon, Jaime; Spence, John R; Langor, David W

    2011-08-01

    Logging is the main human disturbance in the boreal forest; thus, understanding the effects of harvesting practices on biodiversity is essential for a more sustainable forestry. To assess changes in spider composition because of harvesting, samples were collected from three forest layers (overstory, understory, and ground) of deciduous and conifer dominated stands in the northwestern Canadian boreal mixedwood forest. Spider assemblages and feeding guild composition were compared between uncut controls and stands harvested to 20% retention. In total, 143 spider species were collected, 74 from the ground, 60 from the understory, and 71 from the overstory, and species composition of these three pools differed considerably among layers. Distinctive spider assemblages were collected from the canopy of each forest cover type but these were only slightly affected by harvesting. However, logging had a greater impact on the species composition in the understory and ground layers when compared with unharvested controls. Guild structure differed among layers, with wandering and sheet-weaving spiders dominant on the ground while orb-weaving and ambush spiders were better represented in the understory and overstory, respectively. Given the ecological importance of spiders and the expectation of faunal changes with increased harvesting, further efforts toward the understanding of species composition in higher strata of the boreal forest are needed.

  13. 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.

  14. 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.

  15. Scaling foliar respiration to the stand level throughout the growing season in a Quercus rubra forest.

    PubMed

    Xu, Cheng-Yuan; Griffin, Kevin L

    2008-04-01

    Stand-level, canopy foliar carbon loss (R(can)) was modeled for a virtual Quercus rubra L. monoculture at two sites differing in soil water availability in a northeastern deciduous forest (USA) throughout the 2003 growing season. Previously reported foliar respiratory temperature responses of Q. rubra were used to parameterize a full distributed physiology model that estimates R(can) by integrating the effects of season, site and canopy position, and represents the best estimation of R(can). Model sensitivity to five simplified parameterization scenarios was tested, and a reasonable procedure of simplification was established. Neglecting effects of season, site or canopy position on respiration causes considerable relative error in R(can) estimation. By contrast, assuming a constant E(0) (a temperature response variable of the respiration model), or a constant night temperature (mean nighttime temperature) caused only a small relative error (< 10%) compared with the full model. From June 8 to October 28, 2003, modeled R(can) of the virtual Q. rubra monoculture was, on average, 45.3 mmol CO(2) m(-2) night(-1) on a ground-area basis (or 334 mmol CO(2) kg(-1) night(-1) on a biomass basis) and 101 mmol CO(2) m(-2) night(-1) (or 361 mmol CO(2) kg(-1) night(-1)) at the drier site and the more mesic site, respectively. To model R(can) of Q. rubra (or other Quercus species with similar respiratory properties), variations in the base respiration rate across season, site and canopy position need to be fully accounted for, but E(0) may be assumed constant. Modeling R(can) at the mean nighttime temperature would not strongly affect estimated canopy carbon loss.

  16. 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.

  17. 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.

  18. Scaling foliar respiration to the stand level throughout the growing season in a Quercus rubra forest.

    PubMed

    Xu, Cheng-Yuan; Griffin, Kevin L

    2008-04-01

    Stand-level, canopy foliar carbon loss (R(can)) was modeled for a virtual Quercus rubra L. monoculture at two sites differing in soil water availability in a northeastern deciduous forest (USA) throughout the 2003 growing season. Previously reported foliar respiratory temperature responses of Q. rubra were used to parameterize a full distributed physiology model that estimates R(can) by integrating the effects of season, site and canopy position, and represents the best estimation of R(can). Model sensitivity to five simplified parameterization scenarios was tested, and a reasonable procedure of simplification was established. Neglecting effects of season, site or canopy position on respiration causes considerable relative error in R(can) estimation. By contrast, assuming a constant E(0) (a temperature response variable of the respiration model), or a constant night temperature (mean nighttime temperature) caused only a small relative error (< 10%) compared with the full model. From June 8 to October 28, 2003, modeled R(can) of the virtual Q. rubra monoculture was, on average, 45.3 mmol CO(2) m(-2) night(-1) on a ground-area basis (or 334 mmol CO(2) kg(-1) night(-1) on a biomass basis) and 101 mmol CO(2) m(-2) night(-1) (or 361 mmol CO(2) kg(-1) night(-1)) at the drier site and the more mesic site, respectively. To model R(can) of Q. rubra (or other Quercus species with similar respiratory properties), variations in the base respiration rate across season, site and canopy position need to be fully accounted for, but E(0) may be assumed constant. Modeling R(can) at the mean nighttime temperature would not strongly affect estimated canopy carbon loss. PMID:18244949

  19. Tree species diversity and its relationship to stand parameters and geomorphology features in the eastern Black Sea region forests of Turkey.

    PubMed

    Ozcelik, Ramazan; Gul, Altay Ugur; Merganic, Jan; Merganicova, Katarina

    2008-05-01

    We studied the effects of stand parameters (crown closure, basal area, stand volume, age, mean stand diameter number of trees, and heterogeneity index) and geomorphology features (elevation, aspect and slope) on tree species diversity in an example of untreated natural mixed forest stands in the eastern Black Sea region of Turkey. Tree species diversity and basal area heterogeneity in forest ecosystems are quantified using the Shannon-Weaver and Simpson indices. The relationship between tree species diversity basal area heterogeneity stand parameters and geomorphology features are examined using regression analysis. Our work revealed that the relationship between tree species diversity and stand parameters is loose with a correlation coefficient between 0.02 and 0.70. The correlation of basal area heterogeneity with stand parameters fluctuated between 0.004 and 0.77 (R2). According to our results, stands with higher tree species diversity are characterised by higher mean stand diameter number of diameter classes, basal area and lower homogeneity index value. Considering the effect of geomorphology features on tree species or basal area heterogeneity we found that all investigated relationships are loose with R < or = 0.24. A significant correlation was detected only between tree species diversity and aspect. Future work is required to verify the detected trends in behaviour of tree species diversity if it is to estimate from the usual forest stand parameters and topography characteristics.

  20. 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

  1. Seeing the forest for the heterogeneous trees: stand-scale resource distributions emerge from tree-scale structure.

    PubMed

    Boyden, Suzanne; Montgomery, Rebecca; Reich, Peter B; Palik, Brian

    2012-07-01

    Forest ecosystem processes depend on local interactions that are modified by the spatial pattern of trees and resources. Effects of resource supplies on processes such as regeneration are increasingly well understood, yet we have few tools to compare resource heterogeneity among forests that differ in structural complexity. We used a neighborhood approach to examine understory light and nutrient availability in a well-replicated and large-scale variable-retention harvesting experiment in a red pine forest in Minnesota, USA. The experiment included an unharvested control and three harvesting treatments with similar tree abundance but different patterns of retention (evenly dispersed as well as aggregated retention achieved by cutting 0.1- or 0.3-ha gaps). We measured light and soil nutrients across all treatments and mapped trees around each sample point to develop an index of neighborhood effects (NI). Field data and simulation modeling were used to test hypotheses that the mean and heterogeneity of resource availability would increase with patchiness because of greater variation in competitive environments. Our treatments dramatically altered the types and abundances of competitive neighborhoods (NI) in each stand and resulted in significantly nonlinear relationships of light, nitrogen and phosphorus availability to NI. Hence, the distribution of neighborhoods in each treatment had a significant impact on resource availability and heterogeneity. In dense control stands, neighborhood variation had little impact on resource availability, whereas in more open stands (retention treatments), it had large effects on light and modest effects on soil nutrients. Our results demonstrate that tree spatial pattern can affect resource availability and heterogeneity in explainable and predictable ways, and that neighborhood models provide a useful tool for scaling heterogeneity from the individual tree to the stand. These insights are needed to anticipate the outcomes of

  2. 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

  3. 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.

    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.

  4. The impact of disturbance and ensuing forestry practices on Collembola in monitored stands of windthrown forest in the Tatra National Park (Slovakia).

    PubMed

    Čuchta, Peter; Miklisová, Dana; Kováč, Lubomír

    2013-06-01

    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 4 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 ordination method used demonstrated a significant influence of treatment on the abundance of Collembola. ANOVA used confirmed significant differences for all dominant species between treatments. 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 3 years after the event. Moreover, we show that clearing of windthrown spruce forests after a windstorm is less favourable for communities of soil collembolans and slows down the recovery process.

  5. Modelling evapotranspiration at three boreal forest stands using the CLASS: tests of parameterizations for canopy conductance and soil evaporation

    NASA Astrophysics Data System (ADS)

    Bartlett, Paul A.; McCaughey, J. Harry; Lafleur, Peter M.; Verseghy, Diana L.

    2003-03-01

    The performance of the Canadian Land Surface Scheme (CLASS) was evaluated in off-line runs, using data collected at three boreal forest stands located near Thompson, Manitoba: young jack pine, mature jack pine, and mature black spruce. The data were collected in the late spring through autumn of 1994 and 1996, as part of the Boreal Ecosystem-Atmosphere Study (BOREAS).The diurnal range in modelled soil heat flux was exaggerated at all sites. Soil evaporation was modelled poorly at the jack pine stands, with overestimation common and a step change to low evaporation as the soil dried. Replacing the soil evaporation algorithm, which was based on the estimation of a surface relative humidity value, with one based on soil moisture in the top soil layer reduced the overestimation and eliminated the step changes. Modelled water movement between soil layers was too slow at the jack pine stands. Modifying the soil hydraulic parameters to match an observed characteristic curve at the young jack pine stand produced a soil water suction that agreed more closely with measurements and improved drainage between soil layers.The latent heat flux was overestimated and the sensible heat flux underestimated at all three stands. New Jarvis-Stewart-type canopy conductance algorithms were developed from stomatal conductance measurements. At the jack pine stands, stomatal conductance scaled by leaf area index reproduced canopy conductance, but a reduction in the scaled stomatal conductance by one half was necessary at the black spruce stand, indicating a nonlinearity in the scaling of stomatal conductance for this ecosystem. The root-mean-squared error for daily average latent heat flux for the control run of the CLASS and for the best test run are 49 W m-2 and 14 W m-2 respectively at the young jack pine stand, 50 W m-2 and 15 W m-2 respectively at the old jack pine stand, and 48 W m-2 and 13 W m-2 respectively at the old black spruce stand.

  6. 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

  7. Predicting Stand-Level Fire Behavior From Forest Community Data in Former Prairie and Savanna

    NASA Astrophysics Data System (ADS)

    Yospin, G. I.; Bridgham, S. D.; Kertis, J.; Johnson, B. R.

    2009-05-01

    As development pressures continue to expand the extent of the wildland-urban interface (WUI), the ability to predict fire regimes there becomes increasingly important. Such predictions will be particularly valuable to land managers who seek to reduce wildfire risk and to restore imperiled ecosystems within the WUI. Our study focused on remnant and former upland prairie and oak savanna ecosystems in the southern Willamette Valley, Oregon, which were widespread prior to Euro-American settlement but now occupy less than 2% of their historic range. Prairie and savanna grasslands provide habitat for several endangered species, as well as important ecosystem services, such as the regulation of fire regimes. We sampled over 250 plots from seven sites that were grasslands with few to no trees circa 1850 but now have markedly different communities, ranging from prairie to dense forest. We collected data on community composition, topography and fuel loadings. With the BehavePlus fire model, we calculated surface and crown fire parameters. We built two classification and regression trees (CARTs) that used plant community data to group plots on the basis of their surface-fire and crown-fire behavior, respectively. Fuel loads differed significantly by community type, although trends in fuel loadings were neither monotonic across communities nor intuitive. Fuel characteristics were extremely sensitive to topography, and may result from successional history and the presence of exotic invasive species. Though the CARTs were statistically significant, they generally had poor predictive power, which is indicative of the amount of variability inherent in wildland fire. There was greater variability in fire behavior for more intense fires, indicating that land managers can improve the precision of their predictions by managing for less intense fire regimes. The CARTs suggested that surface fires differed among nine different community types and crown fire behavior differed among five

  8. 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.

  9. 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

  10. 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

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

    PubMed

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

    2011-07-15

    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.

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

    PubMed

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

    2011-07-15

    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

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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

  18. 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.

  19. New Voices, Old Beliefs: Forest Environmentalism among New and Long-Standing Rural Residents.

    ERIC Educational Resources Information Center

    Fortmann, Louise; Kusel, Jonathan

    1990-01-01

    Compares environmental attitudes of formerly urban and longstanding rural residents near two national forests. Tests hypotheses that both types equally likely to hold proenvironment perspectives on forest use and tend to be equally dissatisfied with federal environmental policies. Results disprove link between residential status and environmental…

  20. 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.

  1. 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.

  2. Species differences in timing of leaf fall and foliage chemistry modify nutrient resorption efficiency in deciduous temperate forest stands.

    PubMed

    Niinemets, Ulo; Tamm, Ulo

    2005-08-01

    Extensive variation in fractional resorption of mineral elements from plant leaves is still not fully understood. In multi-species forest stands, species leaf fall phenology and leaf constitution may significantly modify the timing of nutrient return to the soil and overall plant nutrient loss. We studied leaf fall and nutrient loss kinetics, and leaf composition in three natural, temperate, deciduous broadleaf forest stands to determine the role of timing of leaf abscission and nutrient immobilization in cell walls on nutrient resorption efficiency of senescing leaves. Nitrogen (N), phosphorus and potassium contents decreased continuously in attached leaves after peak physiological activity during mid-season. Changes in nutrient contents of attached leaves were paralleled by decreases in nutrient contents in freshly fallen leaf litter. In different species and for different nutrients, resorption of nutrients from senescing leaves proceeded with different kinetics. The maximum nutrient resorption efficiency (the fraction of specific nutrient resorbed from the leaves at the end of leaf fall) did not depend on the mid-seasonal nutrient concentration. Species with earlier leaf fall resorbed leaf nutrients at a faster rate, partly compensating for the earlier leaf fall. Nevertheless, the litter-mass weighted mean nutrient contents in leaf litter were still larger in species with earlier leaf fall, demonstrating an inherent trade-off between early leaf fall and efficient nutrient resorption. This trade-off was most important for N. Losses of the non-mobile nutrients calcium and magnesium were unaffected by the timing of leaf fall. There was large variation in the maximum N resorption efficiency among species. Correlations among leaf chemical variables suggested that the maximum N resorption efficiency decreased with the increasing fraction of cell walls in the leaves, possibly due to a greater fraction of N occluded in cell wall matrix. We conclude that species leaf

  3. 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

  4. Investigation and comparison of natural regeneration structure of forest stands in protected and non-protected areas in Arasbaran.

    PubMed

    Alijanpour, Ahmad; Mahmoudzadeh, Ahmad

    2007-05-15

    In this study, a part of Arasbaran forest stands in two protected and non-protected areas have been compared for quantitative and qualitative factors of regeneration. Thus, using aerial photographs of 1967 in the scale of 1:20000, the similarity of these stands was examined and the comparable stands were chosen. Afterward, 77 circle plots of 0.01 ha in protected area and in the same way 77 circle plots of 0.01 ha in non-protected area with a grid size of 250x250 m were established. In each plot, all species with diameter at breast height (dbh) from zero to 7.5 cm were measured. According to the results the number of regeneration average in protected area was significantly higher than that in non-protected area. Oak and Hornbeam regeneration percentages showed highest significant difference in the selected areas. Additionally, these two species have the highest mixture percentage. The regeneration structure in both areas includes high and coppice systems, but coppice is prevalent. In both regions cutting, branching and grazing are the most important destructive factors, and the effects of these factors are higher in non-protected area.

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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.

  11. Stand-level gas-exchange responses to seasonal drought in very young versus old Douglas-fir forests of the Pacific Northwest, USA.

    PubMed

    Wharton, Sonia; Schroeder, Matt; Bible, Ken; Falk, Matthias; Paw U, Kyaw Tha

    2009-08-01

    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 (ES) stands (0-15 years old) and an old-growth (OG) (approximately 450-500 years old) forest in the Wind River Experimental Forest, Washington, USA. We use eddy covariance flux measurements of carbon dioxide (F(NEE)), latent energy (lambdaE) and sensible heat (H) to derive evapotranspiration rate (E(T)), Bowen ratio (beta), water use efficiency (WUE), canopy conductance (G(c)), the Priestley-Taylor coefficient (alpha) and a canopy decoupling factor (Omega). The canopy and bulk parameters are examined to find out how ecophysiological responses to water stress, including changes in relative soil water content ((r)) and vapour pressure deficit (deltae), differ among the two forest successional stages. Despite different rainfall patterns in 2006 and 2007, we observed site-specific diurnal patterns of E(T), alpha, G(c), deltae and (r) during both years. The largest stand differences were (1) at the OG forest high morning G(c) (> 10 mm s(-1)) coincided with high net CO(2) uptake (F(NEE) = -9 to -6 micromol m(-2) s(-1)), but a strong negative response in OG G(c) to moderate deltae was observed later in the afternoons and subsequently reduced daily E(T) and (2) at the ES stands total E(T) was higher (+72 mm) because midday G(c) did not decrease until very low water availability levels ((r) < 30%) were reached at the end of the summer. Our results suggest that ES stands are more likely than mature forests to experience constraints on gas exchange if the dry season becomes longer or intensifies because water conserving ecophysiological responses were observed in the youngest stands only at the very end of the seasonal drought.

  12. 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.

  13. Fuel buildup and potential fire behavior after stand-replacing fires, logging fire-killed trees and herbicide shrub removal in Sierra Nevada forests

    USGS Publications Warehouse

    McGinnis, Thomas W.; Keeley, Jon E.; Stephens, Scott L.; Roller, Gary B.

    2010-01-01

    Typically, after large stand-replacing fires in mid-elevation Sierra Nevada forests, dense shrub fields occupy sites formerly occupied by mature conifers, until eventually conifers overtop and shade out shrubs. Attempting to reduce fuel loads and expedite forest regeneration in these areas, the USDA Forest Service often disrupts this cycle by the logging of fire-killed trees, replanting of conifers and killing of shrubs. We measured the effects of these treatments on live and dead fuel loads and alien species and modeled potential fire behavior and fire effects on regenerating forests. Sampling occurred in untreated, logged and herbicide-treated stands throughout the Sierra Nevada in four large fire areas 4–21 years after stand-replacing fires. Logging fire-killed trees significantly increased total available dead fuel loads in the short term but did not affect shrub cover, grass and forb cover, alien species cover or alien species richness. Despite the greater available dead fuel loads, fire behavior was not modeled to be different between logged and untreated stands, due to abundant shrub fuels in both logged and untreated stands. In contrast, the herbicide treatment directed at shrubs resulted in extremely low shrub cover, significantly greater alien species richness and significantly greater alien grass and forb cover. Grass and forb cover was strongly correlated with solar radiation on the ground, which may be the primary reason that grass and forb cover was higher in herbicide treated stands with low shrub and tree cover. Repeat burning exacerbated the alien grass problem in some stands. Although modeled surface fire flame lengths and rates of spread were found to be greater in stands dominated by shrubs, compared to low shrub cover conifer plantations, surface fire would still be intense enough to kill most trees, given their small size and low crown heights in the first two decades after planting.

  14. [Dissolved aluminum and organic carbon in soil solution under six tree stands in Lushan forest ecosystems].

    PubMed

    Wang, Lianfeng; Pan, Genxing; Shi, Shengli; Zhang, Lehua; Huang, Mingxing

    2003-10-01

    Different depths of soils under 6 tree stands in Lushan Botany Garden were sampled and water-digested at room temperature. The dissolved aluminum and organic carbon were then determined by colorimetry, using 8-hydroxylquilin and TOC Analyzer, respectively. The results indicated that even derived from a naturally identical soil type, the test soils exhibited a diverse solution chemistry, regarding with the Al speciation. The soil solutions under Japanese cedar, giant arborvitae and tea had lower pH values and higher contents of soluble aluminum than those under Giant dogwood, azalea and bamboo. Under giant arborvitae, the lowest pH and the highest content of total soluble aluminum and monomeric aluminum were found in soil solution. There was a significant correlation between soluble aluminum and DOC, which tended to depress the accumulation of toxic monomeric aluminum. The 6 tree stands could be grouped into 2 categories of solution chemistry, according to aluminum mobilization.

  15. [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.

  16. [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

  17. 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.

  18. 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%.

  19. Spatial and temporal rockfall activity in a forest stand in the Swiss Prealps—A dendrogeomorphological case study

    NASA Astrophysics Data System (ADS)

    Perret, Simone; Stoffel, Markus; Kienholz, Hans

    2006-03-01

    Rockfall is a major threat to settlements and transportation routes in large parts of the Alps. While protective forest stands in many locations undoubtedly reduce rockfall risk, little is known about the exact frequency and spatial distribution of rockfall activity in a given place or about how these parameters can be assessed. Therefore, the objective of the present study was to reconstruct rockfall events with dendrogeomorphological methods and to analyse the spatial and temporal rockfall activity in a subalpine forest stand. The study site is located in the transit zone of frequently passing, rather small rockfall fragments (mean diameter of 10 to 20 cm). In all, 33 stem discs from previously felled Picea abies trees found at the foot of Schwarzenberg in Diemtigtal (Swiss Prealps) were sampled, and a total number of 301 rockfall events were dated to between A.D. 1724 and 2002. Results showed that the spatial distribution of rockfall changed slightly with time, and that rockfall activity increased considerably over the last century. In contrast, rockfall magnitude presumably remained on a comparable level. The seasonal occurrence of rockfall showed a clear peak during the dormant season of trees, most probably in early spring. Furthermore, on a 10-year moving average basis, rockfall rates were positively correlated with mean annual as well as summer and winter temperatures. This means that higher temperatures resulted in increased rockfall activity. On the other hand, no correlation with annual or seasonal precipitation totals was revealed. Overall, this study provides an appropriate method for the detailed assessment of spatial and temporal variations in rockfall activity in a given place.

  20. Turbulent Structures in a Pine Forest with a Deep and Sparse Trunk Space: Stand and Edge Regions

    NASA Astrophysics Data System (ADS)

    Dupont, Sylvain; Irvine, Mark R.; Bonnefond, Jean-Marc; Lamaud, Eric; Brunet, Yves

    2012-05-01

    Forested landscapes often exhibit large spatial variability in vertical and horizontal foliage distributions. This variability may affect canopy-atmosphere exchanges through its action on the development of turbulent structures. Here we investigate in neutral stratification the turbulent structures encountered in a maritime pine forest characterized by a high, dense foliated layer associated with a deep and sparse trunk space. Both stand and edge regions are considered. In situ measurements and the results of large-eddy simulations are used and analyzed together. In stand conditions, far from the edge, canopy-top structures appear strongly damped by the dense crown layer. Turbulent wind fluctuations within the trunk space, where the momentum flux vanishes, are closely related to these canopy-top structures through pressure diffusion. Consequently, autocorrelation and spectral analyses are not quite appropriate to characterize the vertical scale of coherent structures in this type of canopy, as pressure diffusion enhances the actual scale of structures. At frequencies higher than those associated with canopy-top structures, wind fluctuations related to wake structures developing behind tree stems are observed within the trunk space. They manifest themselves in wind velocity spectra as secondary peaks in the inertial subrange region, confirming the hypothesis of spectral short-cuts in vegetation canopies. In the edge region specific turbulent structures develop just below the crown layer, in addition to canopy-top structures. They are generated by the wind shear induced by the sub-canopy wind jet that forms at the edge. These structures provide a momentum exchange mechanism similar to that observed at the canopy top but in the opposite direction and with a lower magnitude. They may develop as in plane mixing-layer flows, with some perturbations induced by canopy-top structures. Wake structures are also observed within the trunk space in the edge region.

  1. 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

  2. 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.

  3. Arsenic accumulation in bark beetles and forest birds occupying mountain pine beetle infested stands treated with monosodium methanearsonate.

    PubMed

    Morrissey, Christy A; Albert, Courtney A; Dods, Patti L; Cullen, William R; Lai, Vivian W M; Elliott, John E

    2007-02-15

    The arsenic-based pesticide, monosodium methanearsonate (MSMA), is presently being evaluated for re-registration in Canada and the United States and has been widely used in British Columbia to help suppress Mountain Pine Beetle (MPB) outbreaks. We assessed the availability and exposure of MSMA to woodpeckers and other forest birds that may prey directly on contaminated bark beetles. Total arsenic residues in MPB from MSMA treated trees ranged from 1.3-700.2 microg g(-1) dw (geometric mean 42.0 microg g(-1)) with the metabolite monomethyl arsonic acid (MMAA) contributing 90-97% to the total arsenic extracted. Live adult and larval beetles were collected from treated trees and reached concentrations up to 327 microg g(-1) dw. MPBs from reference trees had significantly lower arsenic concentrations averaging 0.19 microg g(-1) dw. Woodpeckers foraged more heavily on MSMAtreesthat contained beetles with lower arsenic residues, suggesting those trees had reduced MSMAtranslocation and possibly greater live beetle broods. Blood samples from five species of woodpeckers and other forest passerines breeding within 1 km of MSMA stands contained elevated levels of total arsenic but with large individual variability (geometric mean = 0.18 microg g(-1) dw, range 0.02-2.20 microg g(-1). The results indicate that there is significant accumulation and transfer of organic arsenic within the food chain at levels that may present a toxicity risk to avian wildlife.

  4. Effect of environmental variables and stand structure on ecosystem respiration components in a Mediterranean beech forest.

    PubMed

    Guidolotti, Gabriele; Rey, Ana; D'Andrea, Ettore; Matteucci, Giorgio; De Angelis, Paolo

    2013-09-01

    The temporal variability of ecosystem respiration (RECO) has been reported to have important effects on the temporal variability of net ecosystem exchange, the net amount of carbon exchanged between an ecosystem and the atmosphere. However, our understanding of ecosystem respiration is rather limited compared with photosynthesis or gross primary productivity, particularly in Mediterranean montane ecosystems. In order to investigate how environmental variables and forest structure (tree classes) affect different respiration components and RECO in a Mediterranean beech forest, we measured soil, stem and leaf CO2 efflux rates with dynamic chambers and RECO by the eddy-covariance technique over 1 year (2007-2008). Ecosystem respiration showed marked seasonal variation, with the highest rates in spring and autumn and the lowest in summer. We found that the soil respiration (SR) was mainly controlled by soil water content below a threshold value of 0.2 m(3) m(-3), above which the soil temperature explained temporal variation in SR. Stem CO2 effluxes were influenced by air temperature and difference between tree classes with higher rates measured in dominant trees than in co-dominant ones. Leaf respiration (LR) varied significantly between the two canopy layers considered. Non-structural carbohydrates were a very good predictor of LR variability. We used these measurements to scale up respiration components to ecosystem respiration for the whole canopy and obtained cumulative amounts of carbon losses over the year. Based on the up-scaled chamber measurements, the relative contributions of soil, stem and leaves to the total annual CO2 efflux were: 56, 8 and 36%, respectively. These results confirm that SR is the main contributor of ecosystem respiration and provided an insight on the driving factors of respiration in Mediterranean montane beech forests. PMID:24044943

  5. 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

  6. 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.

  7. 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.

  8. Land application of hydrofracturing fluids damages a deciduous forest stand in West Virginia.

    PubMed

    Adams, Mary Beth

    2011-01-01

    In June 2008, 303,000 L of hydrofracturing fluid from a natural gas well were applied to a 0.20-ha area of mixed hardwood forest on the Fernow Experimental Forest, West Virginia. During application, severe damage and mortality of ground vegetation was observed, followed about 10 d later by premature leaf drop by the overstory trees. Two years after fluid application, 56% of the trees within the fluid application area were dead. Ehrh. was the tree species with the highest mortality, and L. was the least affected, although all tree species present on the site showed damage symptoms and mortality. Surface soils (0-10 cm) were sampled in July and October 2008, June and October 2009, and May 2010 on the fluid application area and an adjacent reference area to evaluate the effects of the hydrofracturing fluid on soil chemistry and to attempt to identify the main chemical constituents of the hydrofracturing fluid. Surface soil concentrations of sodium and chloride increased 50-fold as a result of the land application of hydrofracturing fluids and declined over time. Soil acidity in the fluid application area declined with time, perhaps from altered organic matter cycling. This case study identifies the need for further research to help understand the nature and the environmental impacts of hydrofracturing fluids to devise optimal, safe disposal strategies. PMID:21712604

  9. Land application of hydrofracturing fluids damages a deciduous forest stand in West Virginia.

    PubMed

    Adams, Mary Beth

    2011-01-01

    In June 2008, 303,000 L of hydrofracturing fluid from a natural gas well were applied to a 0.20-ha area of mixed hardwood forest on the Fernow Experimental Forest, West Virginia. During application, severe damage and mortality of ground vegetation was observed, followed about 10 d later by premature leaf drop by the overstory trees. Two years after fluid application, 56% of the trees within the fluid application area were dead. Ehrh. was the tree species with the highest mortality, and L. was the least affected, although all tree species present on the site showed damage symptoms and mortality. Surface soils (0-10 cm) were sampled in July and October 2008, June and October 2009, and May 2010 on the fluid application area and an adjacent reference area to evaluate the effects of the hydrofracturing fluid on soil chemistry and to attempt to identify the main chemical constituents of the hydrofracturing fluid. Surface soil concentrations of sodium and chloride increased 50-fold as a result of the land application of hydrofracturing fluids and declined over time. Soil acidity in the fluid application area declined with time, perhaps from altered organic matter cycling. This case study identifies the need for further research to help understand the nature and the environmental impacts of hydrofracturing fluids to devise optimal, safe disposal strategies.

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. 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

  16. Influence of stocking, site quality, stand age, low-severity canopy disturbance, and forest composition on sub-boreal aspen mixedwood carbon stocks

    USGS Publications Warehouse

    Reinikainen, Michael; D’Amato, Anthony W.; Bradford, John B.; Fraver, Shawn

    2014-01-01

    Low-severity canopy disturbance presumably influences forest carbon dynamics during the course of stand development, yet the topic has received relatively little attention. This is surprising because of the frequent occurrence of such events and the potential for both the severity and frequency of disturbances to increase as a result of climate change. We investigated the impacts of low-severity canopy disturbance and average insect defoliation on forest carbon stocks and rates of carbon sequestration in mature aspen mixedwood forests of varying stand age (ranging from 61 to 85 years), overstory composition, stocking level, and site quality. Stocking level and site quality positively affected the average annual aboveground tree carbon increment (CAAI), while stocking level, site quality, and stand age positively affected tree carbon stocks (CTREE) and total ecosystem carbon stocks (CTOTAL). Cumulative canopy disturbance (DIST) was reconstructed using dendroecological methods over a 29-year period. DIST was negatively and significantly related to soil carbon (CSOIL), and it was negatively, albeit marginally, related to CTOTAL. Minima in the annual aboveground carbon increment of trees (CAI) occurred at sites during defoliation of aspen (Populus tremuloides Michx.) by forest tent caterpillar (Malacosoma disstria Hubner), and minima were more extreme at sites dominated by trembling aspen than sites mixed with conifers. At sites defoliated by forest tent caterpillar in the early 2000s, increased sequestration by the softwood component (Abies balsamea (L.) Mill. and Picea glauca (Moench) Voss) compensated for overall decreases in CAI by 17% on average. These results underscore the importance of accounting for low-severity canopy disturbance events when developing regional forest carbon models and argue for the restoration and maintenance of historically important conifer species within aspen mixedwoods to enhance stand-level resilience to disturbance agents and maintain

  17. Wood-inhabiting fungi in southern Italy forest stands: morphogroups, vegetation types and decay classes.

    PubMed

    Granito, Vito Mario; Lunghini, Dario; Maggi, Oriana; Persiani, Anna Maria

    2015-01-01

    The authors conducted an ecological study of forests subjected to varying management. The aim of the study was to extend and integrate, within a multivariate context, knowledge of how saproxylic fungal communities behave along altitudinal/vegetational gradients in response to the varying features and quality of coarse woody debris (CWD). The intra-annual seasonal monitoring of saproxylic fungi, based on sporocarp inventories, was used to investigate saproxylic fungi in relation to vegetation types and management categories. We analyzed fungal species occurrence, recorded according to the presence/absence and frequency of sporocarps, on the basis of the harvest season, of coarse woody debris decay classes as well as other environmental and ecological variables. Two-way cluster analysis, DCA and Spearman's rank correlations, for indirect gradient analysis, were performed to identify any patterns of seasonality and decay. Most of the species were found on CWD in an intermediate decay stage. The first DCA axis revealed the vegetational/microclimate gradient as the main driver of fungal community composition, while the second axis corresponded to a strong gradient of CWD decay classes.

  18. 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).

  19. 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.

  20. Workflow to improve the forest management of Eucalyptus globulus stands affected by Gonipterus scutellatus in Galicia, Spain using remote sensing and GIS

    NASA Astrophysics Data System (ADS)

    Alvarez Taboada, M. Flor; Lorenzo Cimadevila, Henrique; Rodriguez Perez, Jose Ramon; Picos Martin, Juan

    2004-10-01

    In Spain there are more than 500,000 ha of Eucalyptus plantations. These represent 3,5% of the national forest and the 25% of the timber harvested. Galicia monocultures of Eucalyptus globulus Labill. plantations cover 177,679 ha, and mixed stands of eucalyptus cover 200,000 ha more. This high productivity has been powered by the absence of pests and pathogens. However, since 1991 the health and productivity of these stands has been threatened by the Eucalyptus snout beetle (Gonipterus scutellatus Gyll.), which causes a severe defoliation to eucalyptus stands in Galicia. The aim of this paper is to establish a workflow to locate the areas affected by the defoliator, and determinate the basics patterns of spatial distribution, in order to predict future hot spots and develop more integrated pests management. This information will be part of a wider Information System, develop to improve the forest management and monitoring of these stands. The damaged area and the level of defoliation will be mapped using satellite imagery. The additional information of stand conditions, such as site index, climate and microclimatic conditions, digital terrain model, dendrometric and dasometric variables, will be integrated also in a Geographical Information System.

  1. 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.

  2. 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.

  3. 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

  4. Emission and Chemical Transformation of Biogenic Volatile Organic Compounds(ECHO)- Investigation in and above a Mixed Forest Stand: An Overview

    NASA Astrophysics Data System (ADS)

    Koppmann, R.; FZJ Echo Team; Kesselmeier, J.; Meixner, F. X.; MPI Echo Team; Warnke, J.; Hoffmann, T.; Aubrun, S.; Leitl, B.; Schatzmann, M.; Dlugi, R.; Zelger, M.; Kleffmann, J.; Neftel, A.; Hansel, A.; Thomas, C.; Neininger, B.

    2003-12-01

    The objective of the ECHO project is to provide a better understanding of forest stands as a complex source of reactive trace gases into the troposphere. This will be achieved by a unique combination of field, laboratory, and simulation experiments investigating chemical and dynamical processes within the canopy and thus the forest stand as a net source of reactive trace compounds into the planetary boundary layer. The field experiments were carried out in the Stetternicher Forest on the area of the Research Center J\\x81lich. The area has been a deciduous forest for more than 300 years and is surrounded by farmland. Dominating tree species are oaks, beech, and birch. Prevailing wind direction is from the south west, more seldom from the south east. The site is only weakly influenced by urban air masses. At the site three towers were set up, which were equipped with a large set of instruments to measure micrometeorological parameters, biogenic and anthropogenic volatile organic compounds, ozone, nitrogen oxides, and CO, as well as radiation in and above the forest. Additionally, measurements of meteorological parameters were done at the meteorological tower up to a height of 120 m and with a SODAR-RASS system up to 300 m. The first field study took place between June 3 and July 12, 2002, the second field campaign between June 23 and August 1, 2003. As a speciality of the ECHO project, important aspects of the different processes determining the net emission from forest stands into the atmosphere are investigated in laboratory and simulation experiments. The chemical processing of the trace gas mixtures observed in the forest stand is investigated in the atmosphere simulation chamber SAPHIR under controlled conditions. This enables a detailed study of the chemical processes under exclusion of transport processes and sensitivity studies by direct modification of individual chemical parameters. Emission and uptake of VOC by plants are investigated in plant chambers

  5. 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

  6. 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.

  7. 13C-isotopic fingerprint of Pinus pinaster Ait. and Pinus sylvestris L. wood related to the quality of standing tree mass in forests from NW Spain.

    PubMed

    Fernandez, Irene; González-Prieto, Serafin J; Cabaneiro, Ana

    2005-01-01

    Pine forest plantations of Pinus pinaster Ait. and P. sylvestris L. located in Galicia, NW Spain, were selected to study the 13C/12C-isotopic fingerprint in wood core samples in order to find possible relationships between the delta(13)C at natural abundance levels and the quality of the standing tree mass. For each pine species, 24 forests growing on acidic soils were studied: half developed over granite and half over schists. Two dominant trees from each plot, corresponding to all possible combinations of forest stands with high or low site index and with adults or young trees, were drilled at the basal part of trunks using a Pressler drill to obtain tree ring samples. The C-isotopic compositions of the litter and the soil organic matter from different soil depths were also determined and statistically significant correlations between these values and the 13C content of the wood were observed. Despite internal variations due to the influence of site index, tree age and parent material, the isotopic fingerprint of P. pinaster wood (mean value delta13C=-26.2+/-0.8 per thousand) significantly differed (P<0.001) from that of P. sylvestris (mean value delta13C=-24.6+/-0.7 per thousand). Relationships between the quality of the stand and the C-isotopic composition of the wood were observed, high quality stands having trees more 13C-depleted than low quality ones. A high correlation between wood delta13C and site index values for P. pinaster stands (r=-0.667, P<0.001) was found, this correlation being even clearer when only P. pinaster growing over schists (r=-0.833, P<0.001) are considered. Again, the correlation between the site index and the wood delta13C of young P. pinaster trees is higher when plots over granite or schists are separately considered. A similar fact occurs for adult P. sylvestris trees from schists stands, high quality specimens being 13C-depleted compared with low quality ones. On the other hand, 13C natural abundance of wood from P. sylvestris

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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

  13. 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.

  14. 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

  15. 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.

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

    PubMed

    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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. [Characteristics of standing vegetation and soil seed bank in desert riparian forest in lower reaches of Tarim River under effects of river-flooding].

    PubMed

    Li, Ji-mei; Xu, Hai-liang; Zhang, Zhan-jiang; Ye, Mao; Wang, Zeng-ru; Li, Yuan

    2008-08-01

    An investigation was made on the standing vegetation and soil seed bank in desert riparian forest in lower reaches of Tarim River under effects of river-flooding. The results showed that the standing vegetation in non-flooded and flooded sites was composed of 14 species in 13 genera of 8 families, and 26 species in 21 genera of 10 families, respectively, and some shallow-rooted and hygrophilous species were recorded in flooded sites. The indices per unit area plant species number, vegetative coverage, plant density, and species diversity of the vegetation were all higher in flooded than in non-flooded sites. The species number of the soil seed bank in flooded sites was 19, with 5 species more than that in non-flooded sites, and the seed bank density in flooded sites was 2.94 times higher than that in non-flooded sites. The proportion of annual herbaceous species seeds in flooded sites increased by 23.07% while that of shrub species seeds decreased by 20.99%, compared with those in non-flooded sites, and the proportion of perennial herbaceous species seeds had less difference between these two sites. River-flooding increased the diversity of soil seed bank. In flooded and non-flooded sites, the co-occurrence species in seed bank and in standing vegetation were 18 and 9, with the similarity coefficients of species composition between soil seed bank and standing vegetation being 0.842 and 0.667, respectively.

  3. Effects of thinning on temperature dynamics and mountain pine beetle activity in a lodgepole pine stand. Forest Service research paper

    SciTech Connect

    Bartos, D.L.; Booth, G.D.

    1994-12-01

    Temperature measurements were made to better understand the role of microclimate on mountain pine beetle, Dendroctonus pondersae Hopkins (Coleoptera:Scolytidae), activity as a result of thinning lodgepole pine stands. Sampling was done over 61 days on the north slope of the Unita Mountain Range in Northeastern Utah. Principal components analysis was applied to all temperature variables. Most of the variation was attributed to two variables, coolest part of the night and hottest part of the day. The thinned stand was approximately 1 deg. C warmer than the unthinned stand.

  4. Assessing Impacts of Mountain Pine Beetle on Forest Stand Structure in Fraser Experimental Forest: Mapping Forest Characteristics Using Spatial Analyses with Landsat Imagery to Support Management Response Strategies and Restoration Efforts in Colorado Mixed-Conifer Forests

    NASA Astrophysics Data System (ADS)

    Favors, J. E.; Burnett, J.; Chignell, S.; Groy, K.; Luizza, M.; Zawacki, W.

    2012-12-01

    Mountain pine beetle (Dendroctonus ponderosae) infestations have reached epidemic proportions across the western United States, with the Colorado Rockies enduring extensive damage. Aerial detection surveys have been effective in measuring rate of spread but have no way of accurately determining how much of the forest over story is affected by beetle mortality. Understanding this impact on forest structure and composition holds great importance for land managers, researchers and community members alike. Using Boosted Regression Tree modeling, Landsat 5 imagery and ancillary datasets, the goal of this project was to more accurately model forest land cover in Fraser Experimental Forest to assist in quantifying beetle mortality across the landscape. Field validation methods included assessment of over 100 plots stratified across the study site and model recalibration to achieve accuracy >80%. Collaborative efforts with local organizations included the U.S. Geological Survey, USDA Forest Service and Colorado State University.

  5. 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

  6. 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

  7. 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.

  8. Random-anisotropy Blume-Emery-Griffiths model

    NASA Technical Reports Server (NTRS)

    Maritan, Amos; Cieplak, Marek; Swift, Michael R.; Toigo, Flavio; Banavar, Jayanth R.

    1992-01-01

    The results are described of studies of a random-anisotropy Blume-Emery-Griffiths spin-1 Ising model using mean-field theory, transfer-matrix calculations, and position-space renormalization-group calculations. The interplay between the quenched randomness of the anisotropy and the annealed disorder introduced by the spin-1 model leads to a rich phase diagram with a variety of phase transitions and reentrant behavior. The results may be relevant to the study of the phase separation of He-3 - He-4 mixtures in porous media in the vicinity of the superfluid transition.

  9. [Characteristics of standing vegetation and soil seed bank in desert riparian forest in lower reaches of Tarim River under effects of river-flooding].

    PubMed

    Li, Ji-mei; Xu, Hai-liang; Zhang, Zhan-jiang; Ye, Mao; Wang, Zeng-ru; Li, Yuan

    2008-08-01

    An investigation was made on the standing vegetation and soil seed bank in desert riparian forest in lower reaches of Tarim River under effects of river-flooding. The results showed that the standing vegetation in non-flooded and flooded sites was composed of 14 species in 13 genera of 8 families, and 26 species in 21 genera of 10 families, respectively, and some shallow-rooted and hygrophilous species were recorded in flooded sites. The indices per unit area plant species number, vegetative coverage, plant density, and species diversity of the vegetation were all higher in flooded than in non-flooded sites. The species number of the soil seed bank in flooded sites was 19, with 5 species more than that in non-flooded sites, and the seed bank density in flooded sites was 2.94 times higher than that in non-flooded sites. The proportion of annual herbaceous species seeds in flooded sites increased by 23.07% while that of shrub species seeds decreased by 20.99%, compared with those in non-flooded sites, and the proportion of perennial herbaceous species seeds had less difference between these two sites. River-flooding increased the diversity of soil seed bank. In flooded and non-flooded sites, the co-occurrence species in seed bank and in standing vegetation were 18 and 9, with the similarity coefficients of species composition between soil seed bank and standing vegetation being 0.842 and 0.667, respectively. PMID:18975737

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. Phylogeographical structure revealed by chloroplast DNA variation in Japanese beech (Fagus crenata Blume).

    PubMed

    Okaura, T; Harada, K

    2002-04-01

    Intraspecific genetic variation in three non-coding chloroplast DNA (cpDNA) regions (trnT-L and trnL-F spacers, and trnL intron) of Japanese beech (Fagus crenata Blume) was investigated. This species is a major constituent of the typical cool-temperate deciduous forests in Japan. Twenty-one F. crenata populations from throughout Japan, and four F. japonica populations, a close relative of F. crenata, were examined. Seven haplotypes were distinguishable in F. crenata based on nucleotide substitutions and indels. Pairwise nucleotide diversities among haplotypes ranged from 0.0000 to 0.0042 for F. crenata, including F. japonica. The geographical distribution of cpDNA haplotypes was found to be highly structured in F. crenata. Four haplotypes predominated: haplotypes FC1 and FC4 are prevalent on the Pacific Ocean coast, haplotype FC6 is prevalent on the Japan sea coast from the San-in district to Hokkaido, whilst haplotype FC3 is restricted to northern Kyushu and the western-most part of Honshu. Two haplotypes (FC5 and FC7) are restricted to single populations and one haplotype (FC2) is a derivative of FC1. Each of these haplotypes, except FC2, are thought to be derived from different glacial refugia. Phylogenetic analysis showed that neither F. crenata nor F. japonica was monophyletic for the haplotypes, suggesting either ancestral polymorphism or ancient introgression between the lineages of these two Fagus species.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. The autotrophic contribution to soil respiration in a northern temperate deciduous forest and its response to stand disturbance.

    PubMed

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

    2012-05-01

    The goal of this study was to evaluate the contribution of oak trees (Quercus spp.) and their associated mycorrhizal fungi to total community soil respiration in a deciduous forest (Black Rock Forest) and to explore the partitioning of autotrophic and heterotrophic respiration. Trees on twelve 75 × 75-m plots were girdled according to four treatments: girdling all the oaks on the plot (OG), girdling half of the oak trees on a plot (O50), girdling all non-oaks on a plot (NO), and a control (C). In addition, one circular plot (diameter 50 m) was created where all trees were girdled (ALL). Soil respiration was measured before and after tree girdling. A conservative estimate of the total autotrophic contribution is approximately 50%, as indicated by results on the ALL and OG plots. Rapid declines in carbon dioxide (CO(2)) flux from both the ALL and OG plots, 37 and 33%, respectively, were observed within 2 weeks following the treatment, demonstrating a fast turnover of recently fixed carbon. Responses from the NO and O50 treatments were statistically similar to the control. A non-proportional decline in respiration rates along the gradient of change in live aboveground biomass complicated partitioning of the overall rate of soil respiration and indicates that belowground carbon flux is not linearly related to aboveground disturbance. Our findings suggest that in this system there is a threshold disturbance level between 35 and 74% of live aboveground biomass loss, beyond which belowground dynamics change dramatically.

  2. 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

  3. 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

  4. 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.

  5. 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

  6. Forest canopy structural controls over throughfall affect soil microbial community structure in an epiphyte-laden maritime oak stand

    NASA Astrophysics Data System (ADS)

    Van Stan, J. T., II; Rosier, C. L.; Schrom, J. O.; Wu, T.; Reichard, J. S.; Kan, J.

    2014-12-01

    Identifying spatiotemporal influences on soil microbial community (SMC) structure is critical to understanding of patterns in nutrient cycling and related ecological services. Since forest canopy structure alters the spatiotemporal patterning of precipitation water and solute supplies to soils (via the "throughfall" mechanism), is it possible changes in SMC structure variability could arise from modifications in canopy elements? Our study investigates this question by monitoring throughfall water and dissolved ion supply to soils beneath a continuum of canopy structure: from a large gap (0% cover) to heavy Tillandsia usneoides L. (Spanish moss) canopy (>90% cover). Throughfall water supply diminished with increasing canopy cover, yet increased washoff/leaching of Na+, Cl-, PO43-, and SO42- from the canopy to the soils (p < 0.01). Presence of T. usneoides diminished throughfall NO3-, but enhanced NH4+, concentrations supplied to subcanopy soils. The mineral soil horizon (0-10 cm) from canopy gaps, bare canopy, and T. usneoides-laden canopy significantly differed (p < 0.05) in soil chemistry parameters (pH, Ca2+, Mg2+, CEC). PCR-DGGE banding patterns beneath similar canopy covers (experiencing similar throughfall dynamics) also produced high similarities per ANalyses Of SIMilarity (ANO-SIM), and clustered together when analyzed by Nonmetric Multidimensional Scaling (NMDS). Correlation analysis of DGGE banding patterns, throughfall dynamics, and soil chemistry yielded significant correlations (p < 0.05) between fungal communities and soil chemical properties significantly differing between canopy cover types (pH: r2 = 0.50; H+ %-base saturation: r2 = 0.48; Ca2+ %-base saturation: r2 = 0.43). Bacterial community structure correlated with throughfall NO3-, NH4+, and Ca2+ concentrations (r2 = 0.37, p = 0.16). These results suggest that modifications of forest canopy structures are capable of affecting mineral-soil horizon SMC structure via the throughfall mechanism when

  7. Neuropharmacological Potential of Gastrodia elata Blume and Its Components

    PubMed Central

    Jang, Jung-Hee; Son, Yeonghoon; Kang, Seong Soo; Bae, Chun-Sik; Kim, Jong-Choon; Kim, Sung-Ho; Shin, Taekyun; Moon, Changjong

    2015-01-01

    Research has been conducted in various fields in an attempt to develop new therapeutic agents for incurable neurodegenerative diseases. Gastrodia elata Blume (GE), a traditional herbal medicine, has been used in neurological disorders as an anticonvulsant, analgesic, and sedative medication. Several neurodegenerative models are characterized by oxidative stress and inflammation in the brain, which lead to cell death via multiple extracellular and intracellular signaling pathways. The blockade of certain signaling cascades may represent a compensatory therapy for injured brain tissue. Antioxidative and anti-inflammatory compounds isolated from natural resources have been investigated, as have various synthetic chemicals. Specifically, GE rhizome extract and its components have been shown to protect neuronal cells and recover brain function in various preclinical brain injury models by inhibiting oxidative stress and inflammatory responses. The present review discusses the neuroprotective potential of GE and its components and the related mechanisms; we also provide possible preventive and therapeutic strategies for neurodegenerative disorders using herbal resources. PMID:26543487

  8. 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

  9. 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

  10. 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

  11. [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

  12. [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.

  13. 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.

  14. How To Be a Young Member of the Middle Class: Socialization in the Novels of Judy Blume.

    ERIC Educational Resources Information Center

    Litton, Joyce A.

    The widespread popularity of the young adult novels of Judy Blume makes them important factors in the socialization process. Almost all of the characters in her books are members of the middle or upper-middle class, and with the exception of some of the characters in 4 of her 15 novels, all are white. Thus, Blume is teaching youth how to be…

  15. Emissions of BVOC from lodgepole pine in response to mountain pine beetle attack in high and low mortality forest stands

    NASA Astrophysics Data System (ADS)

    Duhl, T. R.; Gochis, D.; Guenther, A.; Ferrenberg, S.; Pendall, E.

    2013-01-01

    In this screening study, biogenic volatile organic compound (BVOC) emissions from intact branches of lodgepole pine (Pinus contorta) trees were measured from trees at two forested sites that have been impacted differently by the mountain pine beetle (MPB), with one having higher mortality and the other with lower mortality. Differences in the amounts and chemical diversity of BVOC between the two sites and from apparently healthy trees versus trees in different stages of MPB attack are presented, as well as (for one site) observed seasonal variability in emissions. A brief comparison is made of geological and climatic characteristics as well as prior disturbances (both natural and man-made) at each site. Trees sampled at the site experiencing high MPB-related tree mortality had lower chemodiversity in terms of monoterpene (MT) emission profiles, while profiles were more diverse at the lower-mortality site. Also at the higher-mortality site, MPB-infested trees in various stages of decline had lower emissions of sesquiterpenes (SQTs) compared to healthy trees, while at the site with lower mortality, MPB-survivors had significantly higher SQT emissions during part of the growing season when compared to both uninfested and newly infested trees. SQT profiles differed between the two sites and, like monoterpene and oxygenated VOC profiles, varied through the season. For the low-mortality site in which repeated measurements were made over the course of the early summer-late fall, higher chemical diversity was observed in early- compared to late-season measurements for all compound classes investigated (MT, oxygenated VOC, and SQT), with the amount of change appearing to correlate to the MPB status of the trees studied. Emissions of 2-methyl-3-buten-2-ol (MBO) had a distinct seasonal signal but were not much different between healthy or infested trees, except in trees with dead needles, from which emissions of this compound were negligible, and in late-season MPB survivors

  16. Emissions of BVOC from Lodgepole Pine in response to Mountain Pine Beetle attack in high and low mortality forest stands

    NASA Astrophysics Data System (ADS)

    Duhl, T. R.; Gochis, D.; Guenther, A.; Ferrenberg, S.; Pendall, E.

    2012-07-01

    In this screening study biogenic volatile organic compound (BVOC) emissions from intact branches of lodgepole pine (Pinus contorta) trees were measured from trees at two forested sites that have been impacted differently by the mountain pine beetle (MPB) with one having higher mortality and the other with lower mortality. Differences in the amounts and chemical diversity of BVOC between the two sites and from apparently healthy trees versus trees in different stages of MPB attack are presented, as well as (for one site) observed seasonal variability in emissions. A brief site comparison is made of the hydrological characteristics and prior disturbances (both natural and man-made) at the sites. Trees sampled at the site experiencing high MPB-related tree mortality had lower chemodiversity in terms of monoterpene (MT) emission profiles, while profiles were more diverse at the lower-mortality site. Also at the higher-mortality site, MPB-infested trees in various stages of decline had lower emissions of sesquiterpenes (SQT) compared to healthy trees, while at the site with lower mortality, MPB-survivors had significantly higher SQT emissions during part of the growing season when compared to both uninfested and newly-infested trees. SQT profiles differed between the two sites, and, like monoterpene and oxygenated VOC profiles, varied through the season For the low-mortality site in which repeated measurements were made over the course the early summer-late fall, higher chemical diversity was observed in early- compared to late-season measurements for all compound classes investigated (MT, oxygenated VOC, and SQT), with the amount of change appearing to correlate to the MPB status of the trees studied. Emissions of methyl-3-buten-2-ol had a distinct seasonal signal but were not much different between healthy or infested trees, except in trees with dead needles, from which emissions of this compound were negligible, and in late-season MPB survivors, in which they were

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. Effects of bulk precipitation pH and growth period on cation enrichment in precipitation beneath the canopy of a beech (Fagus moesiaca) forest stand.

    PubMed

    Michopoulos, P; Baloutsos, G; Nakos, G; Economou, A

    2001-12-17

    The effects of bulk precipitation pH and growth period (growing and dormant) on cation enrichment beneath foliage were examined in a beech (Fagus moesiaca) forest stand during a 48-month period. The bulk precipitation pH values ranged from 4.2 to 7.2. The lowest values were observed in winter due to fossil fuel combustion in a nearby big city. The ratio of monthly ion fluxes of throughfall plus stemflow over monthly ion fluxes of bulk precipitation was chosen as an index of cation enrichment and, therefore, as the dependent variable. Bulk precipitation pH and growth period were chosen as independent factors. Precipitation interception (%) by tree canopies was also taken into account. It was found that the pH factor was significant only for H+ ion enrichment suggesting neutralization of H+ ions in the beech canopy, whereas Mg2+ and K+ enrichment were greater in the growing period, probably as a result of leaching. Crown interception was negatively significant for NH4+-N enrichment.

  2. Gastrodia elata Blume (tianma) mobilizes neuro-protective capacities

    PubMed Central

    Manavalan, Arulmani; Ramachandran, Umamaheswari; Sundaramurthi, Husvinee; Mishra, Manisha; Sze, Siu Kwan; Hu, Jiang-Miao; Feng, Zhi Wei; Heese, Klaus

    2012-01-01

    Tianma (Gastrodia elata Blume) is a traditional Chinese medicine (TCM) often used for the treatment of headache, convulsions, hypertension and neurodegenerative diseases. Tianma also modulates the cleavage of the amyloid precursor protein App and cognitive functions in mice. The neuronal actions of tianma thus led us to investigate its specific effects on neuronal signalling. Accordingly, this pilot study was designed to examine the effects of tianma on the proteome metabolism in differentiated mouse neuronal N2a cells using an iTRAQ (isobaric tags for relative and absolute quantitation)-based proteomics research approach. We identified 2178 proteins, out of which 74 were found to be altered upon tianma treatment in differentiated mouse neuronal N2a cells. Based on the observed data obtained, we hypothesize that tianma could promote neuro-regenerative processes by inhibiting stress-related proteins and mobilizing neuroprotective genes such as Nxn, Dbnl, Mobkl3, Clic4, Mki67 and Bax with various regenerative modalities and capacities related to neuro-synaptic plasticity. PMID:22773961

  3. Native and exotic plant cover vary inversely along a climate gradient 11 years following stand-replacing wildfire in a dry coniferous forest, Oregon, USA.

    PubMed

    Dodson, Erich K; Root, Heather T

    2015-02-01

    Community re-assembly following future disturbances will often occur under warmer and more moisture-limited conditions than when current communities assembled. Because the establishment stage is regularly the most sensitive to climate and competition, the trajectory of recovery from disturbance in a changing environment is uncertain, but has important consequences for future ecosystem functioning. To better understand how ongoing warming and rising moisture limitation may affect recovery, we studied native and exotic plant composition 11 years following complete stand-replacing wildfire in a dry coniferous forest spanning a large gradient in climatic moisture deficit (CMD) from warm and dry low elevation sites to relatively cool and moist higher elevations sites. We then projected future precipitation, temperature and CMD at our study locations for four scenarios selected to encompass a broad range of possible future conditions for the region. Native perennials dominated relatively cool and moist sites 11 years after wildfire, but were very sparse at the warmest and driest (high CMD) sites, particularly when combined with high topographic sun exposure. In contrast, exotic species (primarily annual grasses) were dominant or co-dominant at the warmest and driest sites, especially with high topographic sun exposure. All future scenarios projected increasing temperature and CMD in coming decades (e.g., from 4.5% to 29.5% higher CMD by the 2080's compared to the 1971-2000 average), even in scenarios where growing season (May-September) precipitation increased. These results suggest increasing temperatures and moisture limitation could facilitate longer term (over a decade) transitions toward exotic-dominated communities after severe wildfire when a suitable exotic seed source is present.

  4. Azimuthal and radial variations in sap flux density and effects on stand-scale transpiration estimates in a Japanese cedar forest.

    PubMed

    Shinohara, Yoshinori; Tsuruta, Kenji; Ogura, Akira; Noto, Fumikazu; Komatsu, Hikaru; Otsuki, Kyoichi; Maruyama, Toshisuke

    2013-05-01

    Understanding radial and azimuthal variation, and tree-to-tree variation, in sap flux density (Fd) as sources of uncertainty is important for estimating transpiration using sap flow techniques. In a Japanese cedar (Cryptomeria japonica D. Don.) forest, Fd was measured at several depths and aspects for 18 trees, using heat dissipation (Granier-type) sensors. We observed considerable azimuthal variation in Fd. The coefficient of variation (CV) calculated from Fd at a depth of 0-20 mm (Fd1) and Fd at a depth of 20-40 mm (Fd2) ranged from 6.7 to 37.6% (mean = 28.3%) and from 19.6 to 62.5% (mean = 34.6%) for the -azimuthal directions. Fd at the north aspect averaged for nine trees, for which azimuthal measurements were made, was -obviously smaller than Fd at the other three aspects (i.e., west, south and east) averaged for the nine trees. Fd1 averaged for the nine trees was significantly larger than Fd2 averaged for the nine trees. The error for stand-scale transpiration (E) estimates caused by ignoring the azimuthal variation was larger than that caused by ignoring the radial variation. The error caused by ignoring tree-to-tree variation was larger than that caused by ignoring both radial and azimuthal variations. Thus, tree-to-tree variation in Fd would be more important than both radial and azimuthal variations in Fd for E estimation. However, Fd for each tree should not be measured at a consistent aspect but should be measured at various aspects to make accurate E estimates and to avoid a risk of error caused by the relationship of Fd to aspect.

  5. 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

  6. Look What They've Done to Judy Blume!: The "Basalization" of Children's Literature.

    ERIC Educational Resources Information Center

    Goodman, Kenneth S.

    1988-01-01

    Uses one basalized revision of Judy Blume's "The One in the Middle is the Green Kangaroo" to illustrate how publishers change literature to fit their self-imposed constraints. Criticizes publishers' emphasis on learning words and skills, which causes them to fracture and narrow language, and results in adapted and synthetic texts instead of…

  7. 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.

  8. Crop-tree release thinning in 65-year-old commercial cherry-maple stands (5-year results). Forest Service research paper (Final)

    SciTech Connect

    Smith, H.C.; Miller, G.W.; Lamson, N.I.

    1994-09-01

    The report includes a crop-tree release plan which was applied to a 65-year-old cherry-maple stand in north central West Virginia. Criteria were developed for selecting crop trees for high quality sawtimber and veneer products. Five-year stand growth, mortality, and ingrowth using basal areas, volume, relative density, and number of trees were discussed for the treatments.

  9. 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…

  10. 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

  11. 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.

  12. 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.

  13. Study of the Antiferromagnetic Blume-Capel Model on kagomé Lattice

    NASA Astrophysics Data System (ADS)

    Hwang, Chi-Ok; Park, Sojeong; Kwak, Wooseop

    2016-09-01

    We study the anti-ferromagnetic (AF) Ising model and the AF Blume-Capel (BC) model on the kagomé lattice. Using the Wang-Landau sampling method, we estimate the joint density functions for both models on the lattice, and we obtain the exact critical magnetic fields at zero temperature by using the micro-canonical analysis. We also show the patterns of critical lines for the models from micro-canonical analysis.

  14. 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

  15. 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.

  16. 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

  17. 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...

  18. Assessing spatial distribution, stand impacts and rate of Ceratocystis fimbriata induced 'Ohi'a (Metrosideros polymorpha) mortality in a tropical wet forest, Hawai'i Island, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pests or pathogens that affect trees have the potential to fundamentally alter forest composition, structure and function. Throughout the last six years, large areas of otherwise healthy 'ohi'a (Metrosideros polymorpha) trees have been dying rapidly (typically within weeks) in lowland tropical wet f...

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. 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

  4. Phase Diagram of the Antiferromagnetic Blume-Capel Model on Triangular Lattice

    NASA Astrophysics Data System (ADS)

    Park, Sojeong; Kwak, Wooseop

    2016-08-01

    We perform Monte-Carlo simulations of the anti-ferromagnetic (AF) spin-1 Blume- Capel (BC) model and the AF Ising model on triangular lattice. We estimate the exact critical magnetic fields for both models at zero temperature using the Wang-Landau sampling method. We also show the phase diagrams and the critical lines for the models using the joint density functions. We find that the shapes of critical lines for the models are identical, but the phase transitions across the critical lines are different.

  5. Constant-coupling approximation study of spin-1 Blume-Capel model

    NASA Astrophysics Data System (ADS)

    Ekiz, Cesur

    2016-07-01

    In this paper, the equilibrium properties of spin-1 Blume-Capel model are studied by using constant-coupling approximation. The formulation is based on developed by Obokata and Oguchi method, where the dependence upon the thermodynamic variables is determined by a set of two-couple nonlinear algebraic equations. The temperature dependence of the order parameters is examined to characterize the nature (continuous or discontinuous) of the phase transitions and to obtain the metastable and unstable branches. For the system, the effect of the uniaxial anisotropy parameter to phase transitions and stable, metastable and unstable states is discussed on the simple cubic lattice with the coordination number z = 6.

  6. 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.

  7. 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

  8. Atmospheric particulate deposition in temperate deciduous forest ecosystems: interactions with the canopy and nutrient inputs in two beech stands of Northeastern France.

    PubMed

    Lequy, Emeline; Calvaruso, Christophe; Conil, Sébastien; Turpault, Marie-Pierre

    2014-07-15

    As wood harvests are expected to increase to satisfy the need for bio-energy in Europe, quantifying atmospheric nutrient inputs in forest ecosystems is essential for forest management. Current atmospheric measurements only take into account the <0.45 μm fraction and dry deposition is generally modeled. The aims of this study were to quantify atmospheric particulate deposition (APD), the >0.45 μm fraction of atmospheric deposition, below the canopy, to study the influence of the canopy on APD, and to determine the influence of APD below canopy to nutrient input-output budgets with a focus on base cations calcium, magnesium and potassium, and phosphorus. APD was sampled every four weeks by passive collectors. We divided APD into an organic and a mineral fraction, respectively POM and MDD. MDD was divided into a soluble and a hardly soluble fraction in hydrogen peroxide, referred to as S-MDD and H-MDD, respectively. In order to better understand the influence of the canopy on APD, we studied APD in three pathways below the canopy (litterfall, stemflow and throughfall), and in open field. Our results indicated that APD in throughfall (123 ± 64 kg ha(-1)year(-1)) was significantly higher and synchronic with that in open field (33 ±9 kg ha(-1)year(-1)) in the two study sites. This concerned both POM and MDD, suggesting a large interception of APD by foliar surfaces, which is rapidly washed off by rain within four weeks. Throughfall H-MDD was the main pathway with an average of 16 ± 2 kg ha(-1)year(-1). Stemflow and litterfall were neglected. In one study site, canopy intercepted about 8 kg ha(-1)year(-1) of S-MDD. Although base cations and phosphorus inputs by APD are lower than those of <0.45 μm deposition, they contributed from 5 to 32% to atmospheric deposition and improved the nutrient budget in one of the study sites.

  9. Wetting transition in the two-dimensional Blume-Capel model: a Monte Carlo study.

    PubMed

    Albano, Ezequiel V; Binder, Kurt

    2012-06-01

    The wetting transition of the Blume-Capel model is studied by a finite-size scaling analysis of L×M lattices where competing boundary fields ±H_{1} act on the first or last row of the L rows in the strip, respectively. We show that using the appropriate anisotropic version of finite-size scaling, critical wetting in d=2 is equivalent to a "bulk" critical phenomenon with exponents α=-1, β=0, and γ=3. These concepts are also verified for the Ising model. For the Blume-Capel model, it is found that the field strength H_{1c}(T) where critical wetting occurs goes to zero when the bulk second-order transition is approached, while H_{1c}(T) stays nonzero in the region where in the bulk a first-order transition from the ordered phase, with nonzero spontaneous magnetization, to the disordered phase occurs. Interfaces between coexisting phases then show interfacial enrichment of a layer of the disordered phase which exhibits in the second-order case a finite thickness only. A tentative discussion of the scaling behavior of the wetting phase diagram near the tricritical point is also given.

  10. 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.

  11. 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.

  12. Composition and immunotoxicity activity of essential oils from Lindera obtusiloba Blume against Aedes aegypti L.

    PubMed

    Chung, Ill-Min; Moon, Hyung-In

    2011-03-01

    The leaves of Lindera obtusiloba Blume var. obtusiloba were extracted and the major essential oil composition and immunotoxicity effects were studied. The analyses were conducted by gas chromatography and mass spectroscopy (GC-MS) revealed that the essential oils of L. obtusiloba. The L. obtusiloba essential oil yield was 4.23%, and GC/MS analysis revealed that its major constituents were α-copaene (31.42%), β-caryophyllene (32.11%), α-humulene (4.12%), β-farnesene (4.15%), α- cadinene (3.21%) and Nerolidol (6.84%). The essential oil had a significant toxic effect against early fourth-stage larvae of Aedes aegypti L with an LC(50) value of 24.32 ppm and an LC(90) value of 36.42 ppm. PMID:20477554

  13. Far-from-equilibrium growth of magnetic thin films with Blume-Capel impurities.

    PubMed

    Mazzitello, Karina I; Candia, Julián; Albano, Ezequiel V

    2015-04-01

    We investigate the irreversible growth of (2+1)-dimensional magnetic thin films. The spin variable can adopt three states (s(I)=±1,0), and the system is in contact with a thermal bath of temperature T. The deposition process depends on the change of the configuration energy, which, by analogy to the Blume-Capel Hamiltonian in equilibrium systems, depends on Ising-like couplings between neighboring spins (J) and has a crystal field (D) term that controls the density of nonmagnetic impurities (s(I)=0). Once deposited, particles are not allowed to flip, diffuse, or detach. By means of extensive Monte Carlo simulations, we obtain the phase diagram in the crystal field vs temperature parameter space. We show clear evidence of the existence of a tricritical point located at D(t)/J=1.145(10) and k(B)T(t)/J=0.425(10), which separates a first-order transition curve at lower temperatures from a critical second-order transition curve at higher temperatures, in analogy with the previously studied equilibrium Blume-Capel model. Furthermore, we show that, along the second-order transition curve, the critical behavior of the irreversible growth model can be described by means of the critical exponents of the two-dimensional Ising model under equilibrium conditions. Therefore, our findings provide a link between well-known theoretical equilibrium models and nonequilibrium growth processes that are of great interest for many experimental applications, as well as a paradigmatic topic of study in current statistical physics.

  14. 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

  15. 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

  16. 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

  17. 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…

  18. 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.

  19. Heterochirality in Langmuir monolayers and antiferromagnetic Blume-Emery-Griffiths model

    NASA Astrophysics Data System (ADS)

    Pelizzola, A.; Pretti, M.; Scalas, E.

    2000-05-01

    Chirality is quite a common property in organic molecules. Chiral molecules exist in two forms (called enantiomers) which cannot be superimposed by rotations and translations and may have very different biochemical properties. Experiments on Langmuir monolayers made up of chiral amphiphiles have shown that, in most cases, heterochiral interactions dominate, implying the formation of a racemic compound. It has been shown that a monolayer mixture of two enantiomers can be simply described by a two-dimensional (2-D) spin-1 lattice gas [Blume-Emery-Griffiths (BEG) model], where the heterochiral preference is represented by an effective antiferromagnetic coupling. By now just mean field calculations have been performed on this model. Here we present a revisitation of the tripod amphiphile model, proposed by Andelman and de Gennes [D. Andelman and P.-G. de Gennes, Compt. Rend. Acad. Sci. (Paris) 307, 233 (1988)], together with a rigorous proof of the heterochiral preference shown by the model in the hypothesis of van der Waals interactions. Moreover, a cluster variation analysis of the antiferromagnetic BEG model on a triangular lattice is performed and possible interpretations in terms of surface pressure-concentration phase diagrams for monolayer mixtures of enantiomers are discussed. The choice of a triangular lattice has been suggested by the triangularlike structure of condensed phases of Langmuir monolayers, shown by x-ray diffraction experiments.

  20. Composition, antimicrobial activity and in vitro cytotoxicity of essential oil from Cinnamomum zeylanicum Blume (Lauraceae).

    PubMed

    Unlu, Mehmet; Ergene, Emel; Unlu, Gulhan Vardar; Zeytinoglu, Hulya Sivas; Vural, Nilufer

    2010-11-01

    The essential oil from the bark of Cinnamomum zeylanicum Blume was analyzed by GC-MS and bioassays were carried out. Nine constituents representing 99.24% of the oil were identified by GC-MS. The major compounds in the oil were (E)-cinnamaldehyde (68.95%), benzaldehyde (9.94%) and (E)-cinnamyl acetate (7.44%). The antimicrobial activity of the oil was investigated in order to evaluate its efficacy against 21 bacteria and 4 Candida species, using disc diffusion and minimum inhibitory concentration methods. The essential oil showed strong antimicrobial activity against all microorganisms tested. The cytotoxic and apoptotic effects of the essential oil on ras active (5RP7) and normal (F2408) fibroblasts were examined by MTT assay and acridine orange/ethidium bromide staining, respectively. The cytotoxicity of the oil was quite strong with IC(50) values less than 20 μg/mL for both cell lines. 5RP7 cells were affected stronger than normal cells. Morphological observation of apoptotic cells indicated the induction of apoptosis at the high level of the oil, especially in 5RP7 cells. The present study showed the potential antimicrobial and anticarcinogenic properties of the essential oil of cinnamon bark, indicating the possibilities of its potential use in the formula of natural remedies for the topical treatment of infections and neoplasms.

  1. Geometrical mutual information at the tricritical point of the two-dimensional Blume-Capel model

    NASA Astrophysics Data System (ADS)

    Mandal, Ipsita; Inglis, Stephen; Melko, Roger G.

    2016-07-01

    The spin-1 classical Blume-Capel model on a square lattice is known to exhibit a finite-temperature phase transition described by the tricritical Ising CFT in 1  +  1 space-time dimensions. This phase transition can be accessed with classical Monte Carlo simulations, which, via a replica-trick calculation, can be used to study the shape-dependence of the classical Rényi entropies for a torus divided into two cylinders. From the second Rényi entropy, we calculate the geometrical mutual information (GMI) introduced by Stéphan et al (2014 Phys. Rev. Lett. 112 127204) and use it to extract a numerical estimate for the value of the central charge near the tricritical point. By comparing to the known CFT result, c  =  7/10, we demonstrate how this type of GMI calculation can be used to estimate the position of the tricritical point in the phase diagram.

  2. Exactly solvable antiferromagnetic Blume-Capel model on a sawtooth chain.

    PubMed

    Guo, Yan-Ping; Liu, Zhong-Qiang; Xu, Yu-Liang; Kong, Xiang-Mu

    2016-05-01

    The geometrically frustrated spin-1 Blume-Capel model on an infinite sawtooth chain is exactly solved by the transfer matrix method. The magnetization, ground-state phase diagram, magnetocaloric properties, and specific heat of the system are investigated. The results indicate that: (i) Magnetization plateaus appear at zero temperature. Their number depends on the sign of the crystal field D. For D≥0 there are two magnetization plateaus; however, for D<0 five plateaus exist. At a finite temperature, thermal excitation will destroy these plateaus completely. (ii) Phase transition between any two long-range-ordered ground states, whose spin configurations are given in phase diagram, is the first-order one. The macroscopic degeneracy of the ground states described by the entropy only exists at phase coexistence points. (iii) As temperature approaches zero, magnetocaloric properties and entropy change sharply near phase coexistence points. (iv) The crossovers of the specific heat from a single-peak structure to double-peak ones can signal the phase coexistence points in ground-state phase diagram. PMID:27300873

  3. Trema orientalis Linn. Blume: A potential for prospecting for drugs for various uses

    PubMed Central

    Adinortey, Michael Buenor; Galyuon, Isaac K.; Asamoah, Nicholas Oteng

    2013-01-01

    Medicinal plants are used by traditional practitioners to treat several ailments. Ethnomedicinal studies on Trema orientalis Linn. Blume (Ulmaceae) have shown that it is used in the treatment of diabetes mellitus, respiratory diseases, oliguria, and malaria. This article is aimed at providing comprehensive information on the medicinal uses, biology, phytochemical constituents, and pharmacological data available on T. orientalis. This has been done to explore its therapeutic potential for future research opportunities. This review was compiled with information obtained from databases such as Medline, Elsevier, Springer, Science Direct, Pubmed, Google Scholar, and a library search for articles published in peer-reviewed journals. Compounds present in the plant include tannins, saponins, flavanoids, triterpenes, phytosterols, and several constituents of xanthones. Some pharmacological research done on the plant has focused on, hypoglycemic activity, analgesic, anti-inflammatory activities, anti-plasmodial activity, diuretic activity, laxativity effect, anti-convulsant activity, anti-helmintic activity, anti-sickling effect, anti-oxidant, and anti-bacterial activity. This compilation strongly supports the view that T. orientalis has beneficial therapeutic properties, and indicates its potential as an effective herbal remedy for several diseases. The promising results from several research works could be further substantiated by clinical trials. PMID:23922459

  4. Tricriticality of the Blume-Emery-Griffiths model in thin films of stacked triangular lattices

    NASA Astrophysics Data System (ADS)

    El Hog, Sahbi; Diep, H. T.

    2016-03-01

    We study in this paper the Blume-Emery-Griffiths model in a thin film of stacked triangular lattices. The model is described by three parameters: bilinear exchange interaction between spins J, quadratic exchange interaction K and single-ion anisotropy D. The spin Si at the lattice site i takes three values (-1, 0, +1). This model can describe the mixing phase of He-4 (Si = +1,-1) and He-3 (Si = 0) at low temperatures. Using Monte Carlo simulations, we show that there exists a critical value of D below (above) which the transition is of second-(first-)order. In general, the temperature dependence of the concentrations of He-3 is different from layer by layer. At a finite temperature in the superfluid phase, the film surface shows a deficit of He-4 with respect to interior layers. However, effects of surface interaction parameters can reverse this situation. Effects of the film thickness on physical properties will be also shown as functions of temperature.

  5. Tensor Renormalization Group Study of the General Spin-S Blume-Capel Model

    NASA Astrophysics Data System (ADS)

    Yang, Li-Ping; Xie, Zhi-Yuan

    2016-10-01

    We focus on the special situation of D = 2J in the general spin-S Blume-Capel model on a square lattice. Under an infinitesimal external magnetic field, the phase transition behaviors due to the thermal fluctuations are investigated by the newly developed tensor renormalization group method. We clearly demonstrate the phase transition process: in the case of an integer spin-S, there are S first-order phase transitions with the stepwise magnetizations M = S,S - 1, ldots ,0; in the case of a half-odd integer spin-S, there are S - 1/2 first-order phase transitions with corresponding M = S,S - 1, ldots ,1/2 in addition to one continuous phase transition due to spin-flip Z2 symmetry breaking. At low temperatures, all first-order phase transitions are accompanied by the successive disappearance of the spin-component pairs (±s); furthermore, the transition temperature for the nth first-order phase transition is the same, independent of the value of the spin-S. In the absence of a magnetic field, a visualization parameter characterizing the intrinsic degeneracy of the different phases provides a different reference for the phase transition process.

  6. Micropropagation of Codiaeum variegatum (L.) Blume and regeneration induction via adventitious buds and somatic embryogenesis.

    PubMed

    Radice, Silvia

    2010-01-01

    Codiaeum variegatum (L) Blume cv. "Corazon de oro" and cv. "Norma" are successfully micropropagated when culture are initiated with explants taken from newly sprouted shoots. The establishment and multiplication steps are possible when 1 mg/L BA or 1 mg/L IAA and 3 mg/L 2iP are added to MS medium, according to the cultivar respectively selected.Adventive organogenesis and somatic embryogenesis are induced from leaf explants taken from in vitro buds of croton. On leaf-sectioned of "Corazon de oro" cultured in vitro, 1 mg/L BA stimulates continuous somatic embryos development and induces some shoots too. Replacing BA with 1 mg/L TDZ induces up to 100% bud regeneration in the same explants. On the other hand, leaf-sectioned of C. variegatum cv. Norma does not start somatic embryo differentiation if 1 mg/L TDZ is not added to the MS basal medium. Incipient callus is observed after 30 days of culture, and then, subculture to MS with 1 mg/L BA allows the same process to show on the "Corazon de oro" cultivar. Somatic embryos show growth arrest that is partially overcome by transfer to hormone-free basal medium with activated charcoal. Root induction is possible on basal medium plus 1 mg/L IBA. Plantlets in the greenhouse have variegated leaves true-to-type.

  7. Schelling segregation in an open city: A kinetically constrained Blume-Emery-Griffiths spin-1 system

    NASA Astrophysics Data System (ADS)

    Gauvin, Laetitia; Nadal, Jean-Pierre; Vannimenus, Jean

    2010-06-01

    In the 70s Schelling introduced a multiagent model to describe the segregation dynamics that may occur with individuals having only weak preferences for “similar” neighbors. Recently variants of this model have been discussed, in particular, with emphasis on the links with statistical physics models. Whereas these models consider a fixed number of agents moving on a lattice, here, we present a version allowing for exchanges with an external reservoir of agents. The density of agents is controlled by a parameter which can be viewed as measuring the attractiveness of the city lattice. This model is directly related to the zero-temperature dynamics of the Blume-Emery-Griffiths spin-1 model, with kinetic constraints. With a varying vacancy density, the dynamics with agents making deterministic decisions leads to a variety of “phases” whose main features are the characteristics of the interfaces between clusters of agents of different types. The domains of existence of each type of interface are obtained analytically as well as numerically. These interfaces may completely isolate the agents leading to another type of segregation as compared to what is observed in the original Schelling model, and we discuss its possible socioeconomic correlates.

  8. Trema orientalis Linn. Blume: A potential for prospecting for drugs for various uses.

    PubMed

    Adinortey, Michael Buenor; Galyuon, Isaac K; Asamoah, Nicholas Oteng

    2013-01-01

    Medicinal plants are used by traditional practitioners to treat several ailments. Ethnomedicinal studies on Trema orientalis Linn. Blume (Ulmaceae) have shown that it is used in the treatment of diabetes mellitus, respiratory diseases, oliguria, and malaria. This article is aimed at providing comprehensive information on the medicinal uses, biology, phytochemical constituents, and pharmacological data available on T. orientalis. This has been done to explore its therapeutic potential for future research opportunities. This review was compiled with information obtained from databases such as Medline, Elsevier, Springer, Science Direct, Pubmed, Google Scholar, and a library search for articles published in peer-reviewed journals. Compounds present in the plant include tannins, saponins, flavanoids, triterpenes, phytosterols, and several constituents of xanthones. Some pharmacological research done on the plant has focused on, hypoglycemic activity, analgesic, anti-inflammatory activities, anti-plasmodial activity, diuretic activity, laxativity effect, anti-convulsant activity, anti-helmintic activity, anti-sickling effect, anti-oxidant, and anti-bacterial activity. This compilation strongly supports the view that T. orientalis has beneficial therapeutic properties, and indicates its potential as an effective herbal remedy for several diseases. The promising results from several research works could be further substantiated by clinical trials.

  9. Exactly solvable antiferromagnetic Blume-Capel model on a sawtooth chain

    NASA Astrophysics Data System (ADS)

    Guo, Yan-Ping; Liu, Zhong-Qiang; Xu, Yu-Liang; Kong, Xiang-Mu

    2016-05-01

    The geometrically frustrated spin-1 Blume-Capel model on an infinite sawtooth chain is exactly solved by the transfer matrix method. The magnetization, ground-state phase diagram, magnetocaloric properties, and specific heat of the system are investigated. The results indicate that: (i) Magnetization plateaus appear at zero temperature. Their number depends on the sign of the crystal field D . For D ≥0 there are two magnetization plateaus; however, for D <0 five plateaus exist. At a finite temperature, thermal excitation will destroy these plateaus completely. (ii) Phase transition between any two long-range-ordered ground states, whose spin configurations are given in phase diagram, is the first-order one. The macroscopic degeneracy of the ground states described by the entropy only exists at phase coexistence points. (iii) As temperature approaches zero, magnetocaloric properties and entropy change sharply near phase coexistence points. (iv) The crossovers of the specific heat from a single-peak structure to double-peak ones can signal the phase coexistence points in ground-state phase diagram.

  10. 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.

  11. Magnetic properties of the spin-3/2 Blume-Capel model on a hexagonal Ising nanowire

    SciTech Connect

    Kocakaplan, Y.; Ertaş, M.

    2015-10-15

    Magnetic properties, such as magnetizations, internal energy, specific heat, entropy, Helmholtz free energy, and phase diagrams of the spin-3/2 Blume-Capel model on a hexagonal Ising nanowire with core-shell structure are studied by using the effective-field theory with correlations. The hysteresis behaviors of the system are also investigated and the effects of Hamiltonian parameters on hysteresis behaviors are discussed in detail. The obtained results are compared with some theoretical results and a qualitatively good agreement is found.

  12. Low Temperature Analysis of Correlation Functions of the Blume-Emery-Griffiths Model at the Antiquadrupolar-Disordered Interface

    NASA Astrophysics Data System (ADS)

    Lima, Paulo C.

    2016-10-01

    We show that at low temperatures the d dimensional Blume-Emery-Griffiths model in the antiquadrupolar-disordered interface has all its infinite volume correlation functions < prod _{iin A}σ _i^{n_i}rangle _{τ } , where Asubset Z^d is finite and sum _{iin A}n_i is odd, equal zero, regardless of the boundary condition τ . In particular, the magnetization < σ _irangle _{τ } is zero, for all τ . We also show that the infinite volume mean magnetization lim _{Λ → ∞}Big < 1/|Λ |sum _{iin Λ }σ _iBig rangle _{Λ ,τ } is zero, for all τ.

  13. 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.

  14. Canopy light transmittance in Douglas-fir--western hemlock stands.

    PubMed

    Parker, Geoffrey G; Davis, Melinda M; Chapotin, Saharah Moon

    2002-02-01

    We measured vertical and horizontal variation in canopy transmittance of photosynthetically active radiation in five Pseudotsuga menziesii (Mirb.) Franco-Tsuga heterophylla (Raf.) Sarg. (Douglas-fir-western hemlock) stands in the central Cascades of southern Washington to determine how stand structure and age affect the forest light environment. The shape of the mean transmittance profile was related to stand height, but height of mean maximum transmittance was progressively lower than maximum tree height in older stands. The vertical rate of attenuation declined with stand age in both the overstory and understory. A classification of vertical light zones based on the mean and variance of transmittance showed a progressive widening of the bright (low variance and high mean) and transition (high variance and rapid vertical change) zones in older stands, whereas the dim zone (low variance and mean) narrowed. The zone of maximum canopy surface area in height profiles, estimated by inversion of transmittance profiles, changed from relatively high in the canopy in most young stands ("top-heavy") to lower in the canopy in older stands ("bottom-heavy"). In the understory, all stands had similar mean transmittances, but the spatial scale of variation increased with stand age and increasing crown size. The angular distribution of openness was similar in all stands, though the older stands were less open at all angles than the younger stands. Understory openness was generally unrelated to transmittance in the canopy above. Whole-canopy leaf area indices, estimated using three methods of inverting light measurements, showed little correspondence across methods. The observed patterns in light environment are consistent with structural changes occurring during stand development, particularly the diversification of crowns, the creation of openings of various sizes and the elaboration of the outer canopy surface. The ensemble of measurements has potential use in distinguishing

  15. 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.

  16. Culturable bacterial endophytes isolated from Mangrove tree (Rhizophora apiculata Blume) enhance seedling growth in Rice

    PubMed Central

    Deivanai, Subramanian; Bindusara, Amitraghata Santhanam; Prabhakaran, Guruswamy; Bhore, Subhash Janardhan

    2014-01-01

    Background: Endophytic bacteria do have several potential applications in medicine and in other various sectors of biotechnology including agriculture. Bacterial endophytes need to be explored for their potential applications in agricultural biotechnology. One of the potential applications of bacterial endophytes in agricultural is to enhance the growth of the agricultural crops. Hence, this study was undertaken to explore the plant growth promoting potential application of bacterial endophytes. Objective: The objective of this study was to examine the effect of endophytic bacteria from mangrove tree (Rhizophora apiculata Blume) for their efficacy in promoting seedling growth in rice. Materials and Methods: Eight endophytic bacterial isolates (EBIs) isolated from twig and petiole tissues of the mangrove were identified based on their 16S ribosomal ribonucleic acid (rRNA) gene sequence homology. Separately, surface sterilized paddy seeds were treated with cell-free broth and cell suspension of the EBIs. Rice seedlings were analyzed by various bioassays and data was recorded. Results: The gene sequences of the isolates were closely related to two genera namely, Bacillus and Pantoea. Inoculation of EBIs from R. apiculata with rice seeds resulted in accelerated root and shoot growth with significant increase in chlorophyll content. Among the isolates, Pantoea ananatis (1MSE1) and Bacillus amyloliquefaciens (3MPE1) had shown predominance of activity. Endophytic invasion was recognized by the non-host by rapid accumulation of reactive oxygen species (ROS) and was counteracted by the production of hydrogen peroxide (H2O2) and lipid peroxide. The results demonstrated that EBIs from mangrove tree can increase the fitness of the rice seedlings under controlled conditions. Conclusion: These research findings could be useful to enhance the seedling growth and could serve as foundation in further research on enhancing the growth of the rice crop using endophytic bacteria. PMID

  17. 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...

  18. Saw gin stands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The saw gin stand is the heart of the saw ginning system. Almost from the initial filing of patents for the spiked tooth gin and the saw gin in 1794 and 1796 by Whitney and then Holmes respectively (Hughs and Holt, 2015), the saw gin stand has predominated over early roller-type gins in the U.S. co...

  19. 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

  20. 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...

  1. In-stand scenic beauty of variable retention harvests and mature forests in the U.S. Pacific Northwest: the effects of basal area, density, retention pattern and down wood.

    PubMed

    Ribe, Robert G

    2009-10-01

    Tensions between amenity- and timber-based economies in the U.S. and Canadian Pacific Northwest motivated a study of scenic beauty inside mature forests and timber harvests. A diverse sample of regional forests, measures of forest structure, and large, representative samples of photographs and public judges were employed to measure scenic beauty inside un-harvested mature and old-growth forests, and timber harvests. The latter varied systematically in down wood levels and retention level and pattern. Scenic beauty tended to be optimized at a basal area of 110-155 m(3)/ha and/or 700-900 trees/ha. Older forests and those with larger trees were perceived to be more beautiful. In harvests, greater retention levels, less down wood, and dispersed rather than aggregated retention patterns contributed to aesthetic improvements. Green-tree retention harvests offer considerable potential gains in perceived scenic beauty compared to perceived very ugly clearcuts, particularly at higher retention levels. These gains are more reliable from dispersed retention patterns. The silvicultural parameters studied change strength in affecting scenic beauty with changes in retention level. These interactions are explored in relation to a range of scenic quality objectives as an aid to planners, visual impact analysts, and silviculturists.

  2. Comparison of forest edge effects on throughfall deposition in different forest types.

    PubMed

    Wuyts, Karen; De Schrijver, An; Staelens, Jeroen; Gielis, Leen; Vandenbruwane, Jeroen; Verheyen, Kris

    2008-12-01

    This study examined the influence of distance to the forest edge, forest type, and time on Cl-, SO4(2-), NO3(-), and NH4+ throughfall deposition in forest edges. The forests were dominated by pedunculate oak, silver birch, or Corsican/Austrian pine, and were situated in two regions of Flanders (Belgium). Along transects, throughfall deposition was monitored at distances of 0-128 m from the forest edge. A repeated-measures analysis demonstrated that time, forest type, and distance to the forest edge significantly influenced throughfall deposition of the ions studied. The effect of distance to the forest edge depended significantly on forest type in the deposition of Cl-, SO4(2-), and NO3(-): the edge effect was significantly greater in pine stands than in deciduous birch and oak stands. This finding supports the possibility of converting pine plantations into oak or birch forests in order to mitigate the input of nitrogen and potentially acidifying deposition.

  3. Estimation of stand-level leaf area for boreal bryophytes.

    PubMed

    Bond-Lamberty, Ben; Gower, Stith T

    2007-04-01

    Bryophytes dominate the carbon and nitrogen cycling of many poorly drained terrestrial ecosystems and are important in the vegetation-atmosphere exchange of carbon and water, yet few studies have estimated their leaf area at the stand scale. This study quantified the bryophyte-specific leaf area (SLA) and leaf area index (LAI) in a group of different-aged boreal forest stands in well and poorly drained soils. Species-specific SLA (for three feather mosses, four Sphagnum spp. and Aulacomnium palustre mixed with Tomentypnum nitens) was assessed by determining the projected area using a flatbed scanner and cross-sectional geometry using a dissecting microscope. The hemisurface leaf area was computed as the product of SLA and live biomass and was scaled by coverage data collected at all stands. Pleurozium schreberi dominated the spatial coverage, biomass and leaf area in the well-drained stands, particularly the oldest, while S. fuscum and A. palustre were important in the poorly drained stands. Live moss biomass ranged from 47 to 230 g m(-2) in the well-drained stands dominated by feather mosses and from 102 to 228 g m(-2) in the poorly drained stands. Bryophyte SLA varied between 135 and 473 cm(2) g(-1), for A. palustre and S. capillifolium, respectively. SLA was strongly and significantly affected by bryophyte species, but did not vary between stands; in general, there was no significant difference between the SLA of non-Sphagnum mosses. Bryophyte LAI increased with stand age, peaking at 3.1 and 3.7 in the well and poorly drained stands, respectively; this represented approximately 40% of the overstory LAI in the well-drained stands and 100-1,000% in the poorly drained stands, underscoring the important role bryophytes play in the water and carbon budgets of these boreal forests.

  4. Overexpression of PaFT gene in the wild orchid Phalaenopsis amabilis (L.) Blume

    NASA Astrophysics Data System (ADS)

    Semiarti, Endang; Mercuriani, Ixora S.; Rizal, Rinaldi; Slamet, Agus; Utami, Bekti S.; Bestari, Ida A.; Aziz-Purwantoro, Moeljopawiro, S.; Jang, Soenghoe; Machida, Y.; Machida, C.

    2015-09-01

    To shorten vegetative stage and induce transition from vegetative to reproductive stage in orchids, we overexpressed Phalaenopsis amabilis Flowering LocusT (PaFT) gene under the control of Ubiquitin promoter into protocorm of Indonesian Wild Orchid Phalaenopsis amabilis (L.) Blume. The dynamic expression of vegetative gene Phalaenopsis Homeobox1 (POH1) and flowering time gene PaFT has been analyzed. Accumulation of mRNA was detected in shoot and leaves of both transgenic and non transgenic plants by using Reverse transcriptase-PCR (RT-PCR) with specific gene primers for POH1 and PaFT in 24 months old plants. To analyze the POH1 and PaFT genes, three pairs of degenerate primers PaFT degF1R1, F2R2 and F3R3 that amplified 531 bp PaFT cDNA were used. We detected 700 bp PaFTcDNA from leaves and shoots of transgenic plants, but not in NT plants. POH1 mRNA was detected in plants. PaFT protein consists of Phospatidyl Ethanolamine-Binding Protein (PEBP) in interval base 73-483 and CETS family protein at base 7-519, which are important motif for transmembrane protein. We inserted Ubipro::PaFT/pGAS101 into P. amabilis protocorm using Agrobacterium. Analysis of transgenic plants showed that PaFTmRNA was accumulated in leaves of 12 months after sowing, although it is not detected in non transgeic plants. Compare to the wild type (NT plants), ectopic expression of PaFT shows alter phenotype as follows: 31% normal, 19% with short-wavy leaves, 5% form rosette leaves and 45% produced multishoots. Analysis of protein profiles of trasgenic plants showed that a putative PaFT protein (MW 19,7 kDa) was produced in 1eaves and shoots.This means that at 12 months, POH1 gene expression gradually decreased/negatively regulated, the expression of PaFT gene was activated, although there is no flower initiation yet. Some environmental factors might play a role to induce inflorescens. This experiment is in progress.

  5. 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.

  6. 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.

  7. Simultaneous quantitative determination of cinnamaldehyde and methyl eugenol from stem bark of Cinnamomum zeylanicum Blume using RP-HPLC.

    PubMed

    Gursale, Atish; Dighe, Vidya; Parekh, Guarang

    2010-01-01

    A simple, sensitive, and precise reversed-phase high performance liquid chromatographic (HPLC) method has been developed, validated and used for simultaneous quantitative determination of cinnamaldehyde and methyl eugenol from the methanolic extract of dried bark powder of Cinnamomum zeylanicum Blume (family Lauraceae). The ultrasonic extraction method was used for the extraction of these compounds. The reversed-phase HPLC analysis was carried out using a Intersil ODS-3V-C(18) (150 mm x 4.6 mm, 5 microm) column and a mobile phase comprising of methanol-acetonitrile-water in the volume ratio of 35:20:45, delivered at a flow rate of 1.0 cm(3)/min. The detection and quantitation of both the compounds was carried out at 221 nm.

  8. Effect of the Hamiltonian parameters on Blume-Capel Ising ferromagnet system with single-ion anisotropy

    NASA Astrophysics Data System (ADS)

    Batı, Mehmet; Ertaş, Mehmet

    2016-10-01

    The dynamic mean-field approach have been utilized to investigate effect of the Hamiltonian parameters on the dynamic magnetic properties of a Blume-Capel Ising ferromagnet system in two dimensions, comprising a ferromagnetic spins S = ±3/2, ±1/2. The effect of the single-ion anisotropy (d) and the frequency (w) of the external oscillating magnetic field on the dynamic hysteresis cycle (DHC) are explored in detail. It is found that the DHC increases as the d increases and at a certain d, the DHC decreases with increasing the d. Furthermore, the DHC is very sensitive to changes in the w. We also examine the effect of the w on the dynamic phase diagrams and observe the dynamic phase diagrams illustrate richer dynamic critical behavior for higher values of w than for lower values.

  9. 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.

  10. 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.

  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. 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.

  13. 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

  14. 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.

  15. Predicting breeding bird occurrence by stand- and microhabitat-scale features in even-aged stands in the Central Appalachians

    USGS Publications Warehouse

    McDermott, M.E.; Wood, P.B.; Miller, G.W.; Simpson, B.T.

    2011-01-01

    Spatial scale is an important consideration when managing forest wildlife habitat, and models can be used to improve our understanding of these habitats at relevant scales. Our objectives were to determine whether stand- or microhabitat-scale variables better predicted bird metrics (diversity, species presence, and abundance) and to examine breeding bird response to clearcut size and age in a highly forested landscape. In 2004-2007, vegetation data were collected from 62 even-aged stands that were 3.6-34.6. ha in size and harvested in 1963-1990 on the Monongahela National Forest, WV, USA. In 2005-2007, we also surveyed birds at vegetation plots. We used classification and regression trees to model breeding bird habitat use with a suite of stand and microhabitat variables. Among stand variables, elevation, stand age, and stand size were most commonly retained as important variables in guild and species models. Among microhabitat variables, medium-sized tree density and tree species diversity most commonly predicted bird presence or abundance. Early successional and generalist bird presence, abundance, and diversity were better predicted by microhabitat variables than stand variables. Thus, more intensive field sampling may be required to predict habitat use for these species, and management may be needed at a finer scale. Conversely, stand-level variables had greater utility in predicting late-successional species occurrence and abundance; thus management decisions and modeling at this scale may be suitable in areas with a uniform landscape, such as our study area. Our study suggests that late-successional breeding bird diversity can be maximized long-term by including harvests >10. ha in size into our study area and by increasing tree diversity. Some harvesting will need to be incorporated regularly, because after 15 years, the study stands did not provide habitat for most early successional breeding specialists. ?? 2010 Elsevier B.V.

  16. 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.

  17. 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.

  18. 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

  19. 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

  20. 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)

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. Tree species diversity of natural mixed stands in eastern Black Sea and western Mediterranean region of Turkey.

    PubMed

    Ozcelik, Ramazan

    2009-09-01

    Differences in free species diversity of natural mixed stands were compared between the eastern Black sea region (EBSR) and western Mediterranean region (WMR) of Turkey, to clarify the effects of differences in forest structure, focusing on the tree species occurring in each. Species diversity with special reference to stand structure, of natural mixed stands was quantified by Shannon-Wiener index (H'), equitability index (J'), and species richness index (R). All species diversity indices were significantly higher in EBSR than in WMR. According to the coefficients of homogeneity (CH), stands in EBSR are generally have uneven-aged stand structure, but in WMR even-aged stand structure is more common. Uneven-aged stands have more tree species diversity than even-aged forests due to complex vertical forest structure and species composition. According to Pearson's coefficients, species diversity indices and richness are closely related the average stand diameter (Ds) in uneven-aged stands of EBSR, but average stand diameter (Ds), age (A), and stand density (SDI) are the most important stand parameters in even-aged stands of WMR in Turkey.

  6. 77 FR 66578 - San Bernardino National Forest, Mountaintop Ranger District, CA, Santa Ana Watershed Hazardous...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-06

    ... forest structure required by wildlife. The proposed action includes the long-term maintenance of the... forest habitat is characterized by high canopy cover, as well as greater within-stand vertical (e.g... open forest structure with no standing dead trees, down logs, or other fuels on the ground....

  7. 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…

  8. 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.

  9. Quantifying the consequences of conifer succession in aspen stands: decline in a biodiversity-supporting community.

    PubMed

    McCullough, S A; O'Geen, A T; Whiting, M L; Sarr, D A; Tate, K W

    2013-07-01

    Quaking aspen (Populus tremuloides Michaux) stands are important for biodiversity in conifer-dominated forest landscapes. Our goal was to quantify the consequences of conifer succession on understory diversity and litter quality, as well as associated changes in aspen stand condition. We studied aspen stands on national park land in the transition zone between the northern Sierra Nevada and southern Cascade mountain ranges. We field-measured ten metrics of aspen stand condition in 29 aspen stands. Along a gradient of increasing current conifer cover, we observed decreases in herbaceous species diversity and richness and an increase in forest floor O horizon depth. We interpreted aerial photos from 1952 and 1998 to determine whether directional changes in conifer cover had occurred in the stands over the past half century, and used regression modeling to associate succession with the observed range of aspen stand condition. From the period 1952 to 1998, we found that conifer encroachment occurred in half the sampled stands, with an average increase in conifer cover of 1% a year. Aspen were persistent in the remaining stands. Stand cover dynamics and percent total canopy cover interacted to influence species richness, diversity, aspen sprouting, and litter quality. In stands with conifer encroachment, both understory species richness and diversity declined. Although aspen sprouting increased, aspen establishment declined and the relative mass of woody to fine soil litter increased.

  10. Quantifying the consequences of conifer succession in aspen stands: decline in a biodiversity-supporting community.

    PubMed

    McCullough, S A; O'Geen, A T; Whiting, M L; Sarr, D A; Tate, K W

    2013-07-01

    Quaking aspen (Populus tremuloides Michaux) stands are important for biodiversity in conifer-dominated forest landscapes. Our goal was to quantify the consequences of conifer succession on understory diversity and litter quality, as well as associated changes in aspen stand condition. We studied aspen stands on national park land in the transition zone between the northern Sierra Nevada and southern Cascade mountain ranges. We field-measured ten metrics of aspen stand condition in 29 aspen stands. Along a gradient of increasing current conifer cover, we observed decreases in herbaceous species diversity and richness and an increase in forest floor O horizon depth. We interpreted aerial photos from 1952 and 1998 to determine whether directional changes in conifer cover had occurred in the stands over the past half century, and used regression modeling to associate succession with the observed range of aspen stand condition. From the period 1952 to 1998, we found that conifer encroachment occurred in half the sampled stands, with an average increase in conifer cover of 1% a year. Aspen were persistent in the remaining stands. Stand cover dynamics and percent total canopy cover interacted to influence species richness, diversity, aspen sprouting, and litter quality. In stands with conifer encroachment, both understory species richness and diversity declined. Although aspen sprouting increased, aspen establishment declined and the relative mass of woody to fine soil litter increased. PMID:23093369

  11. 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,…

  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. 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.

  14. 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

  15. 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

  16. Effect of cinnamomum zeylanicum blume essential oil on the growth and morphogenesis of some potentially pathogenic Aspergillus species.

    PubMed

    Carmo, Egberto Santos; de Oliveira Lima, Edeltrudes; de Souza, Evandro Leite; de Sousa, Frederico Barbosa

    2008-01-01

    Cinnamomum zeylanicum Blume is known for a wide range of medicinal properties. This study aimed to assess the interference of C. zeylanicum essential oil on the growth and morphogenesis of some potentially pathogenic Aspergillus species. The essential oil presented strong antifungal effect causing the growth inhibition of the assayed strains and development of large growth inhibition zones. MIC50 and MIC90 values were 40 and 80 μL/mL, respectively. 80, 40 and 20 μL/mL of the oil strongly inhibited the radial mycelial growth of A. niger, A. flavus and A. fumigatus along 14 days. 80 and 40 μL/mL of the oil caused a 100% inhibition of the fungal spore germination. Main morphological changes observed under light microscopy provided by the essential oil in the fungal strains were decreased conidiation, leakage of cytoplasm, loss of pigmentation and disrupted cell structure indicating fungal wall degeneration. It is concluded that C. zeylanicum essential oil could be known as potential antifungal compound, particularly, to protect against the growth of Aspergillus species.

  17. Phytochemical Composition and Biological Activities of Selected Wild Berries (Rubus moluccanus L., R. fraxinifolius Poir., and R. alpestris Blume)

    PubMed Central

    Abu Bakar, Mohd Fadzelly; Ismail, Nur Amalina; Isha, Azizul; Mei Ling, Angelina Lee

    2016-01-01

    Berries, from the genus Rubus, are among the vital components in a healthy diet. In this study, 80% methanol extracts from the three wild Rubus species (Rubus moluccanus L., Rubus fraxinifolius Poir., and Rubus alpestris Blume) were evaluated for their phytochemical contents (total phenolics, flavonoid, anthocyanin, and carotenoid content), antioxidant (DPPH, FRAP, and ABTS assays), antiacetylcholinesterase, and antibacterial activities. GC-MS was used for quantification of naturally occurring phytochemicals. The results showed that R. alpestris contained the highest total phenolic [24.25 ± 0.1 mg gallic acid equivalent (GAE)/g] and carotenoid content [21.86 ± 0.63 mg β-carotene equivalents (BC)/g], as well as the highest DPPH scavenging and FRAP activities. The highest total flavonoid [18.17 ± 0.20 mg catechin equivalents (CE)/g] and anthocyanin content [36.96 ± 0.39 mg cyanidin-3-glucoside equivalents (c-3-gE)/g] have been shown by R. moluccanus. For antibacterial assays, R. moluccanus and R. alpestris extracts showed mild inhibition towards Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Salmonella enteritidis. Anticholinesterase activity for all extracts was in the range of 23–26%. The GC-MS analysis revealed the presence of at least 12, 21, and 7 different organic compounds in 80% methanol extracts of R. alpestris, R. moluccanus, and R. fraxinifolius, respectively, which might contribute to the bioactivity. PMID:27437023

  18. Phytochemical Composition and Biological Activities of Selected Wild Berries (Rubus moluccanus L., R. fraxinifolius Poir., and R. alpestris Blume).

    PubMed

    Abu Bakar, Mohd Fadzelly; Ismail, Nur Amalina; Isha, Azizul; Mei Ling, Angelina Lee

    2016-01-01

    Berries, from the genus Rubus, are among the vital components in a healthy diet. In this study, 80% methanol extracts from the three wild Rubus species (Rubus moluccanus L., Rubus fraxinifolius Poir., and Rubus alpestris Blume) were evaluated for their phytochemical contents (total phenolics, flavonoid, anthocyanin, and carotenoid content), antioxidant (DPPH, FRAP, and ABTS assays), antiacetylcholinesterase, and antibacterial activities. GC-MS was used for quantification of naturally occurring phytochemicals. The results showed that R. alpestris contained the highest total phenolic [24.25 ± 0.1 mg gallic acid equivalent (GAE)/g] and carotenoid content [21.86 ± 0.63 mg β-carotene equivalents (BC)/g], as well as the highest DPPH scavenging and FRAP activities. The highest total flavonoid [18.17 ± 0.20 mg catechin equivalents (CE)/g] and anthocyanin content [36.96 ± 0.39 mg cyanidin-3-glucoside equivalents (c-3-gE)/g] have been shown by R. moluccanus. For antibacterial assays, R. moluccanus and R. alpestris extracts showed mild inhibition towards Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Salmonella enteritidis. Anticholinesterase activity for all extracts was in the range of 23-26%. The GC-MS analysis revealed the presence of at least 12, 21, and 7 different organic compounds in 80% methanol extracts of R. alpestris, R. moluccanus, and R. fraxinifolius, respectively, which might contribute to the bioactivity.

  19. PAC (perturbed angular correlation) analysis of defect motion by Blume's stochastic model for I = 5/2 electric quadrupole interactions

    SciTech Connect

    Evenson, W.E. . Dept. of Physics and Astronomy); Gardner, J.A.; Wang, Ruiping . Dept. of Physics); Su, Han-Tzong ); McKale, A.G. )

    1990-01-01

    Using Blume's stochastic model and the approach of Winkler and Gerdau, we have computed-time-dependent effects on perturbed angular correlation (PAC) spectra due to defect motion in solids in the case of I = (5/2) electric quadrupole interactions. We report detailed analysis for a family of simple models: XYZ + Z'' models, in which the symmetry axis of an axial efg is allowed to fluctuate among orientations along x, y, and z axes, and a static axial efg oriented along the z axis is added to the fluctuating efgs. When the static efg is zero, this model is termed the XYZ'' model. Approximate forms are given for G{sub 2}(t) in the slow and rapid fluctuation regimes, i.e. suitable for the low and high temperature regions, respectively. Where they adequately reflect the underlying physical processes, these expressions allow one to fit PAC data for a wide range of temperatures and dopant concentrations to a single model, thus increasing the uniqueness of the interpretation of the defect properties. Application of the models are given for zirconia and ceria ceramics. 14 refs.

  20. Effects of Nitrogen Fertilization on Synthesis of Primary and Secondary Metabolites in Three Varieties of Kacip Fatimah (Labisia Pumila Blume)

    PubMed Central

    Ibrahim, Mohd Hafiz; Jaafar, Hawa Z.E.; Rahmat, Asmah; Rahman, Zaharah Abdul

    2011-01-01

    A split plot 3 by 4 experiment was designed to examine the impact of 15-week variable levels of nitrogen fertilization (0, 90, 180 and 270 kg N/ha) on the characteristics of total flavonoids (TF), total phenolics (TP), total non structurable carbohydrate (TNC), net assimilation rate, leaf chlorophyll content, carbon to nitrogen ratio (C/N), phenyl alanine lyase activity (PAL) and protein content, and their relationships, in three varieties of Labisia pumila Blume (alata, pumila and lanceolata). The treatment effects were solely contributed by nitrogen application; there was neither varietal nor interaction effect observed. As nitrogen levels increased from 0 to 270 kg N/ha, the production of TNC was found to decrease steadily. Production of TF and TP reached their peaks under 0 followed by 90, 180 and 270 kg N/ha treatment. However, net assimilation rate was enhanced as nitrogen fertilization increased from 0 to 270 kg N/ha. The increase in production of TP and TF under low nitrogen levels (0 and 90 kg N/ha) was found to be correlated with enhanced PAL activity. The enhancement in PAL activity was followed by reduction in production of soluble protein under low nitrogen fertilization indicating more availability of amino acid phenyl alanine (phe) under low nitrogen content that stimulate the production of carbon based secondary metabolites (CBSM). The latter was manifested by high C/N ratio in L. pumila plants. PMID:21954355

  1. Comparison of the exact thermodynamics of the AF Blume-Emery-Grifiths and of the spin-1 ferromagnetic Ising models

    NASA Astrophysics Data System (ADS)

    Corrêa Silva, E. V.; Thomaz, M. T.

    2016-11-01

    We study in detail the thermodynamics of the anti-ferromagnetic Blume-Emery-Griffiths (AF BEG) model in the presence of a longitudinal magnetic field. Its thermodynamics is derived from the exact Helmholtz free energy (HFE) of the model, valid for T > 0. Numerical simulations of this model on a periodic space chain with 10 sites (N=10) yield the energy spectra of the model at K/J = 2 for D/J = 1 and D/J = 2, thus helping us compare, for a broad range of temperature, how some (per site) thermodynamic functions with the same value of K/J but distinct values of D/J behave, namely: the z-component of the magnetization, the specific heat and the entropy. These thermodynamic functions of the AF BEG model at K/|J| = 2 are compared to those of the spin-1 ferromagnetic Ising model with D/|J| > 1.5, for which the T=0 phase diagrams of both models are identical. This comparison is done in a large interval of temperature.

  2. Phytochemical Composition and Biological Activities of Selected Wild Berries (Rubus moluccanus L., R. fraxinifolius Poir., and R. alpestris Blume).

    PubMed

    Abu Bakar, Mohd Fadzelly; Ismail, Nur Amalina; Isha, Azizul; Mei Ling, Angelina Lee

    2016-01-01

    Berries, from the genus Rubus, are among the vital components in a healthy diet. In this study, 80% methanol extracts from the three wild Rubus species (Rubus moluccanus L., Rubus fraxinifolius Poir., and Rubus alpestris Blume) were evaluated for their phytochemical contents (total phenolics, flavonoid, anthocyanin, and carotenoid content), antioxidant (DPPH, FRAP, and ABTS assays), antiacetylcholinesterase, and antibacterial activities. GC-MS was used for quantification of naturally occurring phytochemicals. The results showed that R. alpestris contained the highest total phenolic [24.25 ± 0.1 mg gallic acid equivalent (GAE)/g] and carotenoid content [21.86 ± 0.63 mg β-carotene equivalents (BC)/g], as well as the highest DPPH scavenging and FRAP activities. The highest total flavonoid [18.17 ± 0.20 mg catechin equivalents (CE)/g] and anthocyanin content [36.96 ± 0.39 mg cyanidin-3-glucoside equivalents (c-3-gE)/g] have been shown by R. moluccanus. For antibacterial assays, R. moluccanus and R. alpestris extracts showed mild inhibition towards Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Salmonella enteritidis. Anticholinesterase activity for all extracts was in the range of 23-26%. The GC-MS analysis revealed the presence of at least 12, 21, and 7 different organic compounds in 80% methanol extracts of R. alpestris, R. moluccanus, and R. fraxinifolius, respectively, which might contribute to the bioactivity. PMID:27437023

  3. Comparison of the ferromagnetic Blume-Emery-Griffiths model and the AF spin-1 longitudinal Ising model at low temperature

    NASA Astrophysics Data System (ADS)

    Thomaz, M. T.; Corrêa Silva, E. V.

    2016-03-01

    We derive the exact Helmholtz free energy (HFE) of the standard and staggered one-dimensional Blume-Emery-Griffiths (BEG) model in the presence of an external longitudinal magnetic field. We discuss in detail the thermodynamic behavior of the ferromagnetic version of the model, which exhibits magnetic field-dependent plateaux in the z-component of its magnetization at low temperatures. We also study the behavior of its specific heat and entropy, both per site, at finite temperature. The degeneracy of the ground state, at T=0, along the lines that separate distinct phases in the phase diagram of the ferromagnetic BEG model is calculated, extending the study of the phase diagram of the spin-1 antiferromagnetic (AF) Ising model in S.M. de Souza and M.T. Thomaz, J. Magn. and Magn. Mater. 354 (2014) 205 [5]. We explore the implications of the equality of phase diagrams, at T=0, of the ferromagnetic BEG model with K/|J| = - 2 and of the spin-1 AF Ising model for D/|J| > 1/2.

  4. Effect of cinnamomum zeylanicum blume essential oil on the growth and morphogenesis of some potentially pathogenic Aspergillus species

    PubMed Central

    Carmo, Egberto Santos; de Oliveira Lima, Edeltrudes; de Souza, Evandro Leite; de Sousa, Frederico Barbosa

    2008-01-01

    Cinnamomum zeylanicum Blume is known for a wide range of medicinal properties. This study aimed to assess the interference of C. zeylanicum essential oil on the growth and morphogenesis of some potentially pathogenic Aspergillus species. The essential oil presented strong antifungal effect causing the growth inhibition of the assayed strains and development of large growth inhibition zones. MIC50 and MIC90 values were 40 and 80 μL/mL, respectively. 80, 40 and 20 μL/mL of the oil strongly inhibited the radial mycelial growth of A. niger, A. flavus and A. fumigatus along 14 days. 80 and 40 μL/mL of the oil caused a 100% inhibition of the fungal spore germination. Main morphological changes observed under light microscopy provided by the essential oil in the fungal strains were decreased conidiation, leakage of cytoplasm, loss of pigmentation and disrupted cell structure indicating fungal wall degeneration. It is concluded that C. zeylanicum essential oil could be known as potential antifungal compound, particularly, to protect against the growth of Aspergillus species. PMID:24031186

  5. 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.

  6. 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.

  7. 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...

  8. 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…

  9. 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.

  10. 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.

  11. Environmental Systems Test Stand

    NASA Astrophysics Data System (ADS)

    Barta, D.; Young, J.; Ewert, M.; Lee, S.; Wells, P.; Fortson, R.; Castillo, J.

    A test stand has been developed for the evaluation of prototype lighting, environmental control and crop cultivation technologies for plant production within an advanced life support system. Design of the test stand was based on preliminary designs of the center growth bay of the Biomass Production Chamber, one of several modules of the Bioregenerative Planetary Life Support Systems Test Complex (BIO- Plex). It consists of two controlled-environment shelves, each with 4.7 m2 of area for crop growth (150 cm width, 315 cm length). There are two chilled water loops, one for operation at conventional temperatures (5-10C) for air temperature and humidity control and one for operation at higher temperatures (15-50C) for waste heat acquisition and heating. Modular light boxes, utilizing either air-cooled or water- jacketed HPS lamps, have been developed. This modular design will allow for easy replacement of new lighting technologies within the light banks. An advanced data acquisition and control system has been developed utilizing localized, networked- based data acquisition modules and programmed with object-based control software.

  12. Structure and Function of Shisham Forests in Central Himalaya, India: Dry Matter Dynamics

    PubMed Central

    LODHIYAL, NEELU; LODHIYAL, L. S.; PANGTEY, Y. P. S.

    2002-01-01

    The biomass and net primary productivity (NPP) of 5‐ to 15‐year‐old Shisham (Dalbergia sissoo Roxb.) forests growing in central Himalaya were estimated. Allometric equations were developed for all above‐ and below‐ground components of trees and shrubs for each stand. Understorey forest floor biomass and litter fall were also estimated in forest stands. The biomass (dry matter), forest floor biomass (standing crop litter), tree litter fall and NPP of trees and shrubs increased with increasing age of the forest stand, whereas the dry matter and herb NPP decreased significantly (P < 0·001) with increasing age of the forest. Total forest biomass and NPP ranged from 58·7 (5‐year‐old stand) to 136·1 t ha–1 (15‐year‐old stand) and 12·6 (5‐year‐old stand) to 20·3 t ha–1 year–1 (15‐year‐old stand), respectively. Of these values, tree biomass accounted for 85·7 (5‐year‐old stand) to 90·1 % (15‐year‐old) of total forest biomass, and tree NPP for 72·2 (5‐year‐old) to 82·3 % (15‐year‐old) of total forest NPP. The biomass accumulation ratio (BAR) of the bole component (bole wood + bole bark) increased with increasing age of the forest stand. The bole BAR was 5·8 (5‐year‐old stand) to 7·9 (15‐year‐old stand). However, total BAR of the forest stand ranged from 5·5 (5‐year‐old) to 7·5 (15‐year‐old). PMID:12096818

  13. 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.

  14. 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.

  15. Forest structure and downed woody debris in boreal, temperate, and tropical forest fragments.

    PubMed

    Gould, William A; González, Grizelle; Hudak, Andrew T; Hollingsworth, Teresa Nettleton; Hollingsworth, Jamie

    2008-12-01

    Forest fragmentation affects the heterogeneity of accumulated fuels by increasing the diversity of forest types and by increasing forest edges. This heterogeneity has implications in how we manage fuels, fire, and forests. Understanding the relative importance of fragmentation on woody biomass within a single climatic regime, and along climatic gradients, will improve our ability to manage forest fuels and predict fire behavior. In this study we assessed forest fuel characteristics in stands of differing moisture, i.e., dry and moist forests, structure, i.e., open canopy (typically younger) vs. closed canopy (typically older) stands, and size, i.e., small (10-14 ha), medium (33 to 60 ha), and large (100-240 ha) along a climatic gradient of boreal, temperate, and tropical forests. We measured duff, litter, fine and coarse woody debris, standing dead, and live biomass in a series of plots along a transect from outside the forest edge to the fragment interior. The goal was to determine how forest structure and fuel characteristics varied along this transect and whether this variation differed with temperature, moisture, structure, and fragment size. We found nonlinear relationships of coarse woody debris, fine woody debris, standing dead and live tree biomass with mean annual median temperature. Biomass for these variables was greatest in temperate sites. Forest floor fuels (duff and litter) had a linear relationship with temperature and biomass was greatest in boreal sites. In a five-way multivariate analysis of variance we found that temperature, moisture, and age/structure had significant effects on forest floor fuels, downed woody debris, and live tree biomass. Fragment size had an effect on forest floor fuels and live tree biomass. Distance from forest edge had significant effects for only a few subgroups sampled. With some exceptions edges were not distinguishable from interiors in terms of fuels. PMID:19205181

  16. 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…

  17. 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.

  18. Stand density index applied to timber and goshawk habitat objectives in Douglas-fir

    NASA Astrophysics Data System (ADS)

    Lilieholm, Robert J.; Kessler, Winifred B.; Merrill, Karren

    1993-11-01

    Silvicultural guidelines are presented for the management of intermountain Douglas-fir ( Pseudotsuga menziesii) stands for sawtimber production and goshawk ( Accipiter gentilis) nesting habitat in the northern Rocky Mountains. Data from 14 goshawk nest stands in Douglas-fir forests on the Targhee National Forest in Idaho (Patla 1991) were used to characterize the range of stand conditions considered suitable for goshawk nesting. A density management regime is presented using Reineke's stand density index that includes a technical rotation designed to produce sawlogs with a single commercial thinning. On average timber-growing sites, stands reach goshawk habitat suitability when site height is 25 m at age 75 and provide 65 years of goshawk nesting habitat until the final harvest at age 140. Approximately 1320 m3/ha are harvested over the rotation. On higher-quality sites, rotation length declines from 140 to 85 years, of which roughly 35 years are suitable for goshawk nesting.

  19. 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.

  20. 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

  1. Dynamical arrest with zero complexity: The unusual behavior of the spherical Blume-Emery-Griffiths disordered model.

    PubMed

    Rainone, Corrado; Ferrari, Ulisse; Paoluzzi, Matteo; Leuzzi, Luca

    2015-12-01

    The short- and long-time dynamics of model systems undergoing a glass transition with apparent inversion of Kauzmann and dynamical arrest glass transition lines is investigated. These models belong to the class of the spherical mean-field approximation of a spin-1 model with p-body quenched disordered interaction, with p>2, termed spherical Blume-Emery-Griffiths models. Depending on temperature and chemical potential the system is found in a paramagnetic or in a glassy phase and the transition between these phases can be of a different nature. In specific regions of the phase diagram coexistence of low-density and high-density paramagnets can occur, as well as the coexistence of spin-glass and paramagnetic phases. The exact static solution for the glassy phase is known to be obtained by the one-step replica symmetry breaking ansatz. Different scenarios arise for both the dynamic and the thermodynamic transitions. These include: (i) the usual random first-order transition (Kauzmann-like) for mean-field glasses preceded by a dynamic transition, (ii) a thermodynamic first-order transition with phase coexistence and latent heat, and (iii) a regime of apparent inversion of static transition line and dynamic transition lines, the latter defined as a nonzero complexity line. The latter inversion, though, turns out to be preceded by a dynamical arrest line at higher temperature. Crossover between different regimes is analyzed by solving mode-coupling-theory equations near the boundaries of paramagnetic solutions and the relationship with the underlying statics is discussed. PMID:26764675

  2. Toxic effects of Litsea elliptica Blume essential oil on red blood cells of Sprague-Dawley rats*

    PubMed Central

    Taib, Izatus Shima; Budin, Siti Balkis; Siti Nor Ain, Seri Maseran; Mohamed, Jamaludin; Louis, Santhana Raj; Das, Srijit; Sallehudin, Sulaiman; Rajab, Nor Fadilah; Hidayatulfathi, Othman

    2009-01-01

    Litsea elliptica Blume leaves have been traditionally used as medicinal herbs because of its antimutagenicity, chemopreventative and insecticidal properties. In this study, the toxic effects of L. elliptica essential oil against Sprague-Dawley rat’s red blood cells (RBCs) were evaluated. L. elliptica essential oil was given by oral gavage 5 times per week for 3 treated groups in the doses of 125, 250, and 500 mg/(kg body weight), respectively, and the control group received distilled water. Full blood count, RBC osmotic fragility, RBC morphological changes, and RBC membrane lipid were analyzed 28 d after the treatment. Although L. elliptica essential oil administration had significantly different effects on hemoglobin (Hb), mean cell hemoglobin concentration (MCHC), mean cell volume (MCV), and mean cell hemoglobin (MCH) in the experimental groups as compared to the control group (P<0.05), the values were still within the normal range. L. elliptica induced morphological changes of RBC into the form of echinocyte. The percentage of echinocyte increased significantly among the treated groups in a dose-response manner (P<0.001). The concentrations of RBC membrane phospholipids and cholesterol of all treated groups were significantly lower than those of control group (P<0.001). However, the RBC membrane osmotic fragility and total proteins of RBC membrane findings did not differ significantly between control and treated groups (P>0.05). It is concluded that structural changes in the RBC membrane due to L. elliptica essential oil administration did not cause severe membrane damage. PMID:19882755

  3. Dynamical arrest with zero complexity: The unusual behavior of the spherical Blume-Emery-Griffiths disordered model.

    PubMed

    Rainone, Corrado; Ferrari, Ulisse; Paoluzzi, Matteo; Leuzzi, Luca

    2015-12-01

    The short- and long-time dynamics of model systems undergoing a glass transition with apparent inversion of Kauzmann and dynamical arrest glass transition lines is investigated. These models belong to the class of the spherical mean-field approximation of a spin-1 model with p-body quenched disordered interaction, with p>2, termed spherical Blume-Emery-Griffiths models. Depending on temperature and chemical potential the system is found in a paramagnetic or in a glassy phase and the transition between these phases can be of a different nature. In specific regions of the phase diagram coexistence of low-density and high-density paramagnets can occur, as well as the coexistence of spin-glass and paramagnetic phases. The exact static solution for the glassy phase is known to be obtained by the one-step replica symmetry breaking ansatz. Different scenarios arise for both the dynamic and the thermodynamic transitions. These include: (i) the usual random first-order transition (Kauzmann-like) for mean-field glasses preceded by a dynamic transition, (ii) a thermodynamic first-order transition with phase coexistence and latent heat, and (iii) a regime of apparent inversion of static transition line and dynamic transition lines, the latter defined as a nonzero complexity line. The latter inversion, though, turns out to be preceded by a dynamical arrest line at higher temperature. Crossover between different regimes is analyzed by solving mode-coupling-theory equations near the boundaries of paramagnetic solutions and the relationship with the underlying statics is discussed.

  4. 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.

  5. EUV Engineering Test Stand

    SciTech Connect

    Tichenor, D.A.; Kubiak, G.D.; Replogle, W.C.; Klebanoff, L.E.; Wronosky, J.B.; Hale, L.C.; Chapman, H.N.; Taylor, J.S.; Folta, J.A.; Montcalm, C.; Hudyma, R.M.

    2000-02-14

    The Engineering Test Stand (ETS) is an EUV laboratory lithography tool. The purpose of the ETS is to demonstrate EUV full-field imaging and provide data required to support production-tool development. The ETS is configured to separate the imaging system and stages from the illumination system. Environmental conditions can be controlled independently in the two modules to maximize EUV throughput and environmental control. A source of 13.4 nm radiation is provided by a laser plasma source in which a YAG laser beam is focused onto a xenon-cluster target. A condenser system, comprised of multilayer-coated mirrors and grazing-incidence mirrors, collects the EUV radiation and directs it onto a-reflecting reticle. A four-mirror, ring-field optical system, having a numerical aperture of 0.1, projects a 4x-reduction image onto the wafer plane. This design corresponds to a resolution of 70nm at a k{sub 1} of 0.52. The ETS is designed to produce full-field images in step: and-scan mode using vacuum-compatible, one-dimension-long-travel magnetically levitated stages for both reticle and wafer. Reticle protection is incorporated into the ETS design. This paper provides a system overview of the ETS design and specifications.

  6. [Chile: Standing up again].

    PubMed

    Reyes B, Humberto

    2010-03-01

    One of the biggest earthquakes recorded in human history has recently devastated a large part of the Chilean territory and, followed by a Tsunami, destroyed cities, seaports, fishermen's coves, bridges, and countryside houses. This cataclysm affected a large proportion of our population, leaving homeless families, no working tools for work places, hospitals, schools, public buildings, museums. However, the loss of human Uves was small compared to similar disasters. It destroyed part of the national heritage as well as damaged people's living conditions. A national movement started immediately to help and recover, and international resources, both human and technological were also set in motion. As after previous earthquakes in Chile, young M.D.'s and medical students were organized in voluntary groups backed by institutions or by their own organizations and went from large cities as Santiago and others to provide medical and psychological care to those in most need. Young members and students of other health professions (nurses, physical therapists, etc.) were included in these groups or worked in their own ones. National and international experience indicates that the forthcoming months require special care of psychological reactions and sequel (posttraumatic stress symptoms) and health consequences after water pollution, restrictions in housing and deteriorated sanitary conditions. Nevertheless, our country will stand up once more.

  7. Spatiogenetic characteristics of beech stands with different degrees of autochthony

    PubMed Central

    Gregorius, Hans-Rolf; Kownatzki, Dierk

    2005-01-01

    Background Autochthony in forest tree stands is characterized by a number of criteria, among which the range over which stands act as a population has been suggested to play a central role. Therefore, measures are needed for the delineation of populations or the detection of subpopulation structure. It is argued here that methods of population delineation must be based on the combined consideration of spatial distances and genetic differences between adult individuals. Conventional approaches and a set of newly developed methods are applied to seven isozyme loci in four beech stands which are distinguished by different types of forest management based on natural regeneration. Results Permutation analyses show that correlations between spatial distances and genetic differences vary only little in the studied beech stands. In view of the popularity of this and related descriptors of spatiogenetic covariation, this result came as a surprise. The newly developed methods lead to a different conclusion. Significant spatiogenetic structure is indicated in all stands when considering the mean and variance of spatiogenetic separation, where separation is measured by the smallest spatiogenetic difference of an individual from all others. Spatiogenetic difference is measured here by a combination of the spatial distances and genetic differences between individuals. This descriptor indicates the existence of spatiogenetic clusters in the beech stands. In order to arrive at an explicit representation of cluster structure as a representation of subpopulation structure, two types of cluster structure (primary and α-isolated) are distinguished, both of which reflect desirable characteristics of subpopulation structure. Particularly in the α-isolated structure, the proportion of individuals organized in clusters, the effective size, and the effective number of clusters clearly distinguish and consistently rank the four stands with respect to their types of forest management and

  8. 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.

  9. Managing swiss forests: when climate intervenes

    NASA Astrophysics Data System (ADS)

    Combe, Jean

    For more than a century, forest management in Switzerland has been based on a philosophy attuned to nature. Silviculture which imitates natural cycles and processes is believed to promote the growth of healthy, stable forests. Because of the diversity of species and ages, which are often mixed on a small scale, forest stands are able to resist many extremes of climate and, in the event of damage (mainly due to windthrow and snow breakage), the natural forest ecosystem can recover rapidly from total destruction thanks to abundant natural regeneration. Over the long term, Swiss foresters have become accustomed to harvesting 20% of the annual production as "storm timber". The most serious natural disasters are mainly due to extremes of one single climatic factor; e.g. Hurricane Vivian in 1990, which toppled over almost five million m3 of timber — the equivalent of Switzerland's average yearly timber harvest. For a forest manager, however, it is interesting to analyse the less spectacular damage which occurs annually in natural forest stands and accounts for between 12 and 20% of the annual harvest. It appears that a combination of two or three climatic factors has a much greater effect on forest stability than an extreme of one single factor. Wind speeds of up to 100 km/hour may often be harmless to forests, whereas lower speeds may uproot mature trees over a wide area if the soil is waterlogged following a long period of rain. This kind of damage can occur throughout the year in coniferous stands, whereas broadleaved species growing in waterlogged soils may resist winds if this climatic combination comes when the vegetation period is over and they have lost their leaves. A number of such patterns of damage to forest stands is presented and their dependence on the occurrence of a combination of specific climatic factors is proposed.

  10. Post-breeding bird responses to canopy tree retention, stand size, and edge in regenerating Appalachian hardwood stands

    USGS Publications Warehouse

    McDermott, M.E.; Wood, P.B.

    2011-01-01

    Avian use of even-aged timber harvests is likely affected by stand attributes such as size, amount of edge, and retained basal area, all characteristics that can easily be manipulated in timber harvesting plans. However, few studies have examined their effects during the post-breeding period. We studied the impacts of clearcut, low-leave two-age, and high-leave two-age harvesting on post-breeding birds using transect sampling and mist-netting in north-central West Virginia. In our approach, we studied the effects of these harvest types as well as stand size and edge on species characteristic of both early-successional and mature forest habitats. In 2005-2006, 13 stands ranging from 4 to 10. years post-harvest and 4-21. ha in size were sampled from late June through mid-August. Capture rates and relative abundance were similar among treatments for generalist birds. Early-successional birds had the lowest capture rates and fewer species (~30% lower), and late-successional birds reached their highest abundance and species totals (double the other treatments) in high-leave two-age stands. Area sensitivity was evident for all breeding habitat groups. Both generalist and late-successional bird captures were negatively related to stand size, but these groups showed no clear edge effects. Mean relative abundance decreased to nearly zero for the latter group in the largest stands. In contrast, early-successional species tended to use stand interiors more often and responded positively to stand size. Capture rates for this group tripled as stand size increased from 4 to 21. ha. Few birds in the forest periphery responded to harvest edge types despite within-stand edge effects evident for several species. To create suitable habitat for early-successional birds, large, non-linear openings with a low retained basal area are ideal, while smaller harvests and increased residual tree retention would provide habitat for more late-successional birds post-breeding. Although our study

  11. 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

  12. 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

  13. Response of tree growth to climatic variation and stand dynamics: Implications for modeling stand dynamics under varying climatic conditions

    SciTech Connect

    Graumlich, L.J.; Holmes, R.L. )

    1994-06-01

    We used tree-ring data to assess the relative importance of regional climate vs. stand-level processes in controlling tree growth for seven forest dominants of the mixed conifer forest of the Sierra Nevada. For each species, increment cores were collected from at least 20 canopy dominants at several sites arrayed along elevational gradients extending from lower to upper elevational limits. Species sampled include ponderosa pine (Pinus ponderosa), Jeffrey pine (P. jeffreyi), sugar pine (P. lambertina), white fir (Abies concolor), red fir (A. magnifica), incense cedar (Calocedrus decurrens), and black oak (Quercus keloggii). Stand-level processes generate low to medium frequency variation in growth that is not held in common among trees within a site or between sites. Stand-level processes are most important for white and red fir and least important for ponderosa pine. Regional climatic variation generates medium to high frequency variation that is coherent among trees of the same species (and often same genera). Results such as these have utility for parameterizing and validating stand simulation models, especially for use in climatic change scenarios.

  14. [Forest biomass and its dynamics in Pearl River Delta].

    PubMed

    Yang, Kun; Guan, Dong-Sheng

    2007-04-01

    Based on the observation data obtained from 69 sampling sites of different age class forests, and by using biomass expansion factor function, the regression equations of stand biomass and volume of the main forest types in Pearl River Delta were built, and the regional forest biomass and its dynamics were estimated on the basis of forest inventory data. The results showed that most of the forests in Pearl River Delta were of young-medium age, which occupied 80% or more of the total forest area, and their undergrowth biomass accounted for about 33% of the total forest biomass, indicating that the regional forest biomass could be estimated more exactly if undergrowth biomass was fully concerned. In the periods of 1989-1993, 1994-1998 and 1999-2003, the forest biomass in Pearl River Delta increased by 14. 67 x 10(6) t in total, among which, Pinus massoniana forest, evergreen broadleaf forest, and conifer and deciduous mixed forest contributed about 80%. Young-medium age forest biomass accounted for 90% of the total, but the proportion was decreased gradually. The forest area in the Delta almost kept unvaried, and the forest biomass was increasing year after year, with an annual increment of about 1.2%. Better fostering and managing the existing forests is very important to have more forest biomass and better environmental effect that regional forests offered.

  15. EUFODOS: European Forest Downstream Services - Improved Information on Forest Structure and Damage

    NASA Astrophysics Data System (ADS)

    Hirschmugl, M.; Gallaun, H.; Wack, R.; Granica, K.; Schardt, M.

    2013-05-01

    Forests play a key role in the European economy and environment. This role incorporates ecological functions which can be affected by the occurrence of insect infestations, forest fire, heavy snowfall or windfall events. Local or Regional Authorities (LRAs) thus require detailed information on the degradation status of their forests to be able to take appropriate measures for their forest management plans. In the EUFODOS project, state-of-the-art satellite and laser scanning technologies are used to provide forest authorities with cost-effective and comprehensive information on forest structure and damage. One of the six test sites is located in the Austrian province of Styria where regional forest authorities have expressed a strong need for detailed forest parameters in protective forest. As airborne laser-scanning data is available, it will be utilized to derive detailed forest parameters such as the upper forest border line, tree height, growth classes, forest density, vertical structure or volume. At the current project status, the results of (i) the forest border line, (ii) the segmentation of forest stands and (iii) the tree top detection are available and presented including accuracy assessment and interim results are shown for timber volume estimations. The final results show that the forest border can be mapped operationally with an overall accuracy of almost 99% from LiDAR data. For the segmentation of forest stands, a comparison of the automatically derived result with visual-manual delineation showed in general a more detailed segmentation result, but for all visual-manual segments a congruence of 87% within a 4 m buffer. Tree top detections were compared to stem numbers estimated based on angle-count samplings in a field campaign, which led to a correlation coefficient (R) of 0.79.

  16. Coupled forest growth-hydrology modelling as an instrument for the assessment of effects of forest management on hydrology in forested catchments

    NASA Astrophysics Data System (ADS)

    Sutmöller, J.; Hentschel, S.; Hansen, J.; Meesenburg, H.

    2011-03-01

    The type and intensity of forest management directly influences regional catchment hydrology. Future forest management must optimise the effects of its practices to achieve sustainable management. With scenario analysis of forestry practices, the effects of different forest utilisation strategies on the hydrology of forested catchments can be temporally and spatially quantified. The approach adopted in this study necessitated the development of an interactive system for the spatially distributed modelling of hydrology in relation to forest stand development. Consequently, a forest growth model was used to simulate stand development assuming various forest management activities. Selected simulated forest growth parameters were entered into the hydrological model to simulate water fluxes under different conditions of forest structure. The approach enables the spatially differentiated quantification of changes in the water regime (e.g. increased evapotranspiration). The results of hydrological simulations in the study area, the Oker catchment (northern Harz Mountains), show that forests contribute to the protection of water systems because they have a balancing effect on the hydrological regime. As scenario simulations also suggest, however, forestry practices can also lead to substantial changes in water budgets of forested catchments. The preservation of the hydrological services of forests requires a sustainable and long-term forest conversion on the basis of current management directives for near natural silviculture. Management strategies on basis of moderate harvesting regimes are preferred because of their limited impact on the water budget.

  17. Antioxidative activity of the polyphenols from the involucres of Castanea mollissima Blume and their mitigating effects on heat stress.

    PubMed

    Dong, S; Li, H; Gasco, L; Xiong, Y; Guo, K J; Zoccarato, I

    2015-05-01

    Polyphenols extracted from plants have multiple functions in animal production. To explore new sources of tannin-rich extracts, which have potential benefits for animal health, this study focused on the effects of polyphenolic extracts from involucres of Castanea mollissima Blume (PICB) on heat-stressed broilers. In vitro experiments were first performed using intestinal cryptlike epithelial cell line-6 (IEC-6) cells to evaluate the effects of PICB on cell proliferation and antioxidative parameters under normal and heat-stress conditions. Then in vivo experiments were carried out with 2 trials: in trial 1, 400 one-d-old male Arbor Acres (AA) broilers were randomly assigned to 5 groups (4 replicates/group, 20 chicks/replicate): group 1 was a normal control group fed the basic ration; groups 2 to 5 were fed the basic ration supplemented with 0.2% vitamin C and 0.2%, 0.3%, and 0.4% PICB, respectively. Trial 1 lasted 42 d, and growth performance was monitored every week. At the end of the trial, the chicks were sacrificed and sampled. In trial 2, 400 twenty-eight-d-old chicks were randomly assigned to 5 groups as described in trial 1. After 1 week of adaptation, heat stress was applied for 7 consecutive days. On days 3 and 7 of heat stress, the chicks were sacrificed and sampled. The results showed that PICB could stimulate IEC-6 cell proliferation and had strong in vitro antioxidant activity. PICB had no effect on the growth performance and carcass parameters of AA broilers in trial 1, whereas in trial 2, group 4 saw improved growth performance and antioxidant activity compared to the first three groups (P < 0.05). In conclusion, PICB had no effects on the growth performance of IEC-6 cells and AA broilers under normal conditions, whereas it could mitigate heat-stress effects on the growth performance and antioxidant activity of IEC-6 cells and AA broilers, implying that PICB could be used as a suitable additive to improve animal production under heat

  18. Dynamics of fine roots in five Chinese temperate forests

    SciTech Connect

    Quan, Xiankuai; Wang, Chuankuan; Zhang, Q.; Wang, X.; Luo, Y.; Bond-Lamberty, Benjamin

    2010-07-01

    Quantifying fine root production and mortality is crucially needed for modeling forest ecosystem carbon cycling, but the fine root dynamics are poorly understood in Chinese temperate forests. We used a minirhizotron method to investigate spatial and temporal dynamics of fine roots (diameter ≤ 2 mm) in five representative temperate forests in northeastern China. Our specific objectives were to: (1) compare standing crop, production and mortality of fine roots among the five stands; (2) examine fine root phenology for the stands; and (3) examine vertical distribution patterns of fine roots for the stands. Fine root dynamics were significantly affected by forest type, soil layer, sampling time and their interactions. The mean values of fine root standing crop varied from 8.0 to 12.8 mm cm-2; those of production varied from 0.027 to 0.046 mm cm-2 d-1; and those of mortality varied from 0.013 to 0.024 mm cm-2 d-1. All stands had a similar seasonal “sinusoidal” pattern of fine root standing crop, and a “unimodal” pattern of production. However, the seasonal dynamics of the mortality was unsynchronized with that of the production. The minimum values of standing crop, production and mortality occurred in March for all stands, while the maximum values and occurring time differed among forest types. The occurrence of the maximum standing crop varied from DOY (day of year) 222 for the oak stand to DOY 271 for the aspen-birch stand; that of the maximum production varied from DOY 188 for the pine and hardwood stands to DOY 239 for the larch stand; and that of the maximum mortality varied from DOY 222 for the oak and aspen-birch stands to DOY 287 for the larch stand. The standing crop, production and mortality of fine roots tended to decrease with soil depths, of which the relative contribution at 0 -10 cm depth averaged 38%, 46%, and 58% of total, respectively. The fact that the production was approximate twice as great as the mortality suggested a net carbon input to

  19. Carbon storage in old-growth forests of the Mid-Atlantic: toward better understanding the eastern forest carbon sink.

    PubMed

    McGarvey, Jennifer C; Thompson, Jonathan R; Epstein, Howard E; Shugart, Herman H

    2015-02-01

    Few old-growth stands remain in the matrix of secondary forests that dominates the eastern North American landscape. These remnant stands offer insight on the potential carbon (C) storage capacity of now-recovering secondary forests. We surveyed the remaining old-growth forests on sites characteristic of the general Mid-Atlantic United States and estimated the size of multiple components of forest C storage. Within and between old-growth stands, variability in C density is high and related to overstory tree species composition. The sites contain 219 ± 46 Mg C/ha (mean ± SD), including live and dead aboveground biomass, leaf litter, and the soil O horizon, with over 20% stored in downed wood and snags. Stands dominated by tulip poplar (Liriodendron tulipifera) store the most live biomass, while the mixed oak (Quercus spp.) stands overall store more dead wood. Total C density is 30% higher (154 Mg C/ha), and dead wood C density is 1800% higher (46 Mg C/ha) in the old-growth forests than in the surrounding younger forests (120 and 5 Mg C/ha, respectively). The high density of dead wood in old growth relative to secondary forests reflects a stark difference in historical land use and, possibly, the legacy of the local disturbance (e.g., disease) history. Our results demonstrate the potential for dead wood to maintain the sink capacity of secondary forests for many decades to come. PMID:26240851

  20. Carbon storage in old-growth forests of the Mid-Atlantic: toward better understanding the eastern forest carbon sink.

    PubMed

    McGarvey, Jennifer C; Thompson, Jonathan R; Epstein, Howard E; Shugart, Herman H

    2015-02-01

    Few old-growth stands remain in the matrix of secondary forests that dominates the eastern North American landscape. These remnant stands offer insight on the potential carbon (C) storage capacity of now-recovering secondary forests. We surveyed the remaining old-growth forests on sites characteristic of the general Mid-Atlantic United States and estimated the size of multiple components of forest C storage. Within and between old-growth stands, variability in C density is high and related to overstory tree species composition. The sites contain 219 ± 46 Mg C/ha (mean ± SD), including live and dead aboveground biomass, leaf litter, and the soil O horizon, with over 20% stored in downed wood and snags. Stands dominated by tulip poplar (Liriodendron tulipifera) store the most live biomass, while the mixed oak (Quercus spp.) stands overall store more dead wood. Total C density is 30% higher (154 Mg C/ha), and dead wood C density is 1800% higher (46 Mg C/ha) in the old-growth forests than in the surrounding younger forests (120 and 5 Mg C/ha, respectively). The high density of dead wood in old growth relative to secondary forests reflects a stark difference in historical land use and, possibly, the legacy of the local disturbance (e.g., disease) history. Our results demonstrate the potential for dead wood to maintain the sink capacity of secondary forests for many decades to come.

  1. Aspen increase soil moisture, nutrients, organic matter and respiration in Rocky Mountain forest communities.

    PubMed

    Buck, Joshua R; St Clair, Samuel B

    2012-01-01

    Development and change in forest communities are strongly influenced by plant-soil interactions. The primary objective of this paper was to identify how forest soil characteristics vary along gradients of forest community composition in aspen-conifer forests to better understand the relationship between forest vegetation characteristics and soil processes. The study was conducted on the Fishlake National Forest, Utah, USA. Soil measurements were collected in adjacent forest stands that were characterized as aspen dominated, mixed, conifer dominated or open meadow, which includes the range of vegetation conditions that exist in seral aspen forests. Soil chemistry, moisture content, respiration, and temperature were measured. There was a consistent trend in which aspen stands demonstrated higher mean soil nutrient concentrations than mixed and conifer dominated stands and meadows. Specifically, total N, NO(3) and NH(4) were nearly two-fold higher in soil underneath aspen dominated stands. Soil moisture was significantly higher in aspen stands and meadows in early summer but converged to similar levels as those found in mixed and conifer dominated stands in late summer. Soil respiration was significantly higher in aspen stands than conifer stands or meadows throughout the summer. These results suggest that changes in disturbance regimes or climate scenarios that favor conifer expansion or loss of aspen will decrease soil resource availability, which is likely to have important feedbacks on plant community development.

  2. Single Baseline Tomography SAR for Forest Above Ground Biomass Estimation

    NASA Astrophysics Data System (ADS)

    Li, Wenmei; Chen, Erxue; Li, Zengyuan; Wang, Xinshuang; Feng, Qi

    2013-01-01

    Single baseline tomography SAR is used for forest height estimation as its little restriction on the number of baselines and configurations of tracks in recent years. There existed two kinds of single baseline tomography SAR techniques, the polarimetric coherence tomography (PCT) and the sum of Kronecker product (SKP), algebraic synthesis (AS) and Capon spectral estimator approach (SKP-AS-Capon). Few researches on forest above ground biomass (AGB) estimation are there using single baseline tomography SAR. In this paper, PCT and SKP-AS-Capon approaches are proposed for forest AGB estimation. L-band data set acquired by E-SAR airborne system in 2003 for the forest test site in Traunstein, is used for this experiment. The result shows that single baseline polarimetric tomography SAR can obtain forest AGB in forest stand scale, and SKP-AS-Capon method has better detailed vertical structure information, while the Freeman 3-component combined PCT approach gets a homogenous vertical structure in forest stand.

  3. Adaptive forest management for drinking water protection under climate change

    NASA Astrophysics Data System (ADS)

    Koeck, R.; Hochbichler, E.

    2012-04-01

    Drinking water resources drawn from forested catchment areas are prominent for providing water supply on our planet. Despite the fact that source waters stemming from forested watersheds have generally lower water quality problems than those stemming from agriculturally used watersheds, it has to be guaranteed that the forest stands meet high standards regarding their water protection functionality. For fulfilling these, forest management concepts have to be applied, which are adaptive regarding the specific forest site conditions and also regarding climate change scenarios. In the past century forest management in the alpine area of Austria was mainly based on the cultivation of Norway spruce, by the way neglecting specific forest site conditions, what caused in many cases highly vulnerable mono-species forest stands. The GIS based forest hydrotope model (FoHyM) provides a framework for forest management, which defines the most crucial parameters in a spatial explicit form. FoHyM stratifies the spacious drinking water protection catchments into forest hydrotopes, being operational units for forest management. The primary information layer of FoHyM is the potential natural forest community, which reflects the specific forest site conditions regarding geology, soil types, elevation above sea level, exposition and inclination adequately and hence defines the specific forest hydrotopes. For each forest hydrotope, the adequate tree species composition and forest stand structure for drinking water protection functionality was deduced, based on the plant-sociological information base provided by FoHyM. The most important overall purpose for the related elaboration of adaptive forest management concepts and measures was the improvement of forest stand stability, which can be seen as the crucial parameter for drinking water protection. Only stable forest stands can protect the fragile soil and humus layers and hence prevent erosion process which could endanger the water

  4. Standing Waves on a Shoestring.

    ERIC Educational Resources Information Center

    Hendrix, Laura

    1992-01-01

    Describes the construction of a wave generator used to review the algebraic relationships of wave motion. Students calculate and measure the weight needed to create tension to generate standing waves at the first eight harmonics. (MDH)

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

    NASA Astrophysics Data System (ADS)

    Khlyustov, V.

    2012-04-01

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

  6. Germination and Initial Growth of Fagus orientalis Seedling under Different Stand Canopies

    NASA Astrophysics Data System (ADS)

    Tabari, Masoud

    Germination and early growth of Fagus orientalis seedling were studied in four stands with different canopy closures (closed, semi-closed, relatively-opened and opened stands) under a dominant beech forest, located in north of Iran. For this purpose, 196 beech seed-sown plastic pots (in four plots of 49 units) were set up under each canopy closure. In the beginning of the first growing season germination rate ranged between 78.1 and 84.7% in different stands but there was no statistically significant difference of this term in the stands. In the end of the first growing season survival rate of seedlings was 73.9-76.1% under closed and semi-closed stands. It decreased significantly to 31.7 and 18.0% under relatively-opened and opened stands, respectively. Shoot length was, in the order 70 and 90 mm in closed and semi-closed stands. It decreased to 40 and 30 mm in relatively-opened and opened stands, respectively. Vitality appeared mostly with high quality in closed and semi-closed stands and with low quality in relatively-opened and opened stands. Leaf biomass reduced in closed stand. There was an increase for leaf area in semi-closed stand and for Specific Leaf Weight (SLW) in relatively-opened and opened stands. Generally, the investigation shows that in the first growing season most characteristics of beech seedling were benefited from more favorable conditions in the denser stands (closed and semi-closed canopies).

  7. 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.

  8. Interesting times on Krakatau: stand dynamics in the 1990s.

    PubMed

    Whittaker, R J; Partomihardjo, T; Jones, S H

    1999-11-29

    The Krakatau Islands, Indonesia, have provided an opportunity for ecologists to track primary succession from the 'clean slate' of 1883, through forest closure in the 1920s, to the contemporary period, in which successional changes take the form of alterations in composition and stature of forest stands rather than gross changes in ecosystem type. This paper reports on permanent forest plots established on the islands in 1989, and fully surveyed again in both 1992 and 1997. Since 1989, the plots have been subject to natural disturbance phenomena in the form of varying combinations of, for example, deposition of volcanic ejecta, landslides, lightning strikes, storm damage and drought. These effects have been concentrated between 1992 and 1997, during which the volcano Anak Krakatau has deposited ash on the islands of Sertung and Panjang, but not on Rakata. Data on stand responses are presented for growth rates (dbh (diameter at breast height, 1.3 m) increment), stem recruitment and mortality, biomass changes partitioned into mortality, ingrowth and growth of established trees), and compositional shifts. The discussion focuses on evaluation of questions and successional models framed earlier in the programme. One general finding is that the stand dominants as of 1989 have tended to decline in number within the plots, generally through low levels of recruitment failing to balance rates of mortality. The effects of disturbance to the plots appear to be evident in terms of mortality and recruitment, dbh increment, and changes in biomass. The patterns of change in the eight plots are quite varied, such that relatively few generalizations are possible. The difficulties of establishing meaningful baseline rates for tree growth and stand biomass are discussed. PMID:11605628

  9. Analysing land cover changes for understanding of forest dynamics using temporal forest management plans.

    PubMed

    Kadioğullari, Ali İhsan; Sayin, Mehmet Ali; Çelįk, Durmuş Ali; Borucu, Süleyman; Çįl, Bayram; Bulut, Sinan

    2014-04-01

    This study analyses forest dynamics and land use/land cover change over a 43-year period using spatial-stand-type maps of temporal forest management plans of Karaisalı Forest Enterprise in the Eastern Mediterranean Region of Turkey. Stand parameters (tree species, crown closures and developmental stages) of the dynamics and changes caused by natural or artificial intervention were introduced and mapped in a Geographic Information System (GIS) and subjected to fragmentation analysis using FRAGSTATS. The Karaisalı Forest Enterprise was first planned in 1969 and then the study area was planned under the Mediterranean Forest Use project in 1991 and five-term forest management plans were made. In this study, we analysed only four periods (excluding 1982 revision plans): 1969, 1991, 2002 and 2012. Between 1969 and 2012, overall changes included a net increase of 3,026 ha in forested areas. Cumulative forest improvement accounted for 2.12% and the annual rate of total forest improvement averaged 0.08%. In addition, productive forest areas increased from 36,174 to 70,205 ha between 1969 and 2012. This translates into an average annual productive forest improvement rate of 1.54%. At the same time, fully covered forest areas with crown closure of "3" (>70%) increased about 21,321 ha, and young forest areas in developmental stage of "a" (diameter at breast height (dbh) < 8 cm) increased from 716 to 13,305 ha over the 43-year study period. Overall changes show that productive and fully covered forest areas have increased egregiously with a focus on regenerated and young developmental stages. A spatial analysis of metrics over the 43-year study period indicated a more fragmented landscape resulting in a susceptible forest to harsh disturbances. PMID:24254492

  10. Movement and ranging patterns of the Common Chaffinch in heterogeneous forest landscapes

    PubMed Central

    Kubiczek, Katrin; Böhm, Stefan M.; Wells, Konstans

    2014-01-01

    The partitioning of production forests into discretely managed forest stands confronts animals with diversity in forest attributes at scales from point-level tree assemblages to distinct forest patches and range-level forest cover. We have investigated the movement and ranging patterns of male Common Chaffinches, Fringilla coelebs, in heterogeneous forest production landscapes during spring and summer in south-western Germany. We radio-tracked a total of 15 adult males, each for up to six days, recording locations at 10-min intervals. We then performed point-level tree surveys at all tracking locations and classified forest stand attributes for the areal covering of birds’ ranges. Movement distances were shortest in beech forest stands and longer in spruce-mixed and non-spruce conifer stands. Movement distances increased with stand age in beech stands but not in others, an effect that was only detectable in a multilevel hierarchical model. We found negligible effects of point-level tree assemblages and temperature on movement distances. Daily range estimates were from 0.01 to 8.0 hectare (median of 0.86 ha) with no evident impact of forest attributes on ranging patterns but considerable intra-individual variation in range sizes over consecutive days. Most daily ranges covered more than one forest stand type. Our results show that forest management impacts the movement behaviour of chaffinches in heterogeneous production forest. Although point-level effects of movement distances are weak compared with stand-level effects in this study, the hierarchical organization of forest is an important aspect to consider when analysing fine-scale movement and might exert more differentiated effects on bird species that are more sensitive to habitat changes than the chaffinch. PMID:25024900

  11. Managing for biodiversity in young Douglas-fir forests of western Oregon

    USGS Publications Warehouse

    Muir, Patricia S.; Mattingly, Rosanna L.; Tappeiner, John C.; Bailey, John D.; Elliott, Wayne E.; Hagar, Joan C.; Miller, Jeffrey C.; Peterson, Eric B.; Starkey, Edward E.

    2002-01-01

    This project addressed potential contributions of forest thinning to enhancing biodiversity and accelerating development of old-growth characteristics in relatively young Douglas-fir forests typical of those managed according to the Northwest Forest Plan. Studies focused primarily on 32 paired unthinned and thinned stands and 20 associated old-growth stands in the Coast Range and Cascade mountains of western Oregon. Data were collected on vascular plants in most stands surveyed, and on epiphytic lichens and bryophytes, moths, and birds in subsets of these stands. Studies assessed whether or not (1) communities of organisms differed among stand types, (2) communities in thinned stands were more similar to those in old-growth stands than were those in unthinned stands, (3) species diversity or abundance was related to specific stand features, and (4) these specific stand features were shared across taxa. Results indicated that communities differed among stand types, and that communities in thinned stands were not necessarily more similar to old-growth communities than were those in unthinned stands. Variation in stand conditions appeared to enhance biodiversity, and hardwood trees and shrubs were important for many species. These and other results form the basis for general thinning guidelines, which are presented here, and will guide future research.

  12. Analysis of AIS data of the Bonanza Creek Experimental Forest, Alaska

    NASA Technical Reports Server (NTRS)

    Spanner, M. A.; Peterson, D. L.

    1986-01-01

    Airborne Imaging Spectrometer (AIS) data were acquired in 1985 over the Bonanza Creek Experimental Forest, Alaska for the analysis of canopy characteristics including biochemistry. Concurrent with AIS overflights, foliage from fifteen coniferous and deciduous forest stands were analyzed for a variety of biochemical constituents including nitrogen, lignin, protein, and chlorophyll. Preliminary analysis of AIS spectra indicates that the wavelength region between 1450 to 1800 namometers (nm) displays distinct differences in spectral response for some of the forest stands. A flat field subtraction (forest stand spectra - flat field spectra) of the AIS spectra assisted in the interpretation of features of the spectra that are related to biology.

  13. Mapping aboveground forest biomass combining dendrometric data and spectral signature of forest species

    NASA Astrophysics Data System (ADS)

    Avocat, H.; Tourneux, F.

    2013-12-01

    Accurate measures and explicit spatial representations of forest biomass compose an important aspect to model the forest productivity and crops, and to implement sustainable forest management. Several methods have been developed to estimate and to map forest biomass, combining point-sources measurements of biophysical variables such as diameter-at-breast height (DBH), tree height, crown size, crown length, crown volume and remote sensing data (spectral vegetation index values). In this study, we propose a new method for aboveground biomass (AGB) mapping of forests and isolated trees. This method is tested on a 1100 km2 area located in the eastern France. In contrast to most of studies, our model is not calibrated using field plot measurements or point-source inventory data. The primary goal of this model is to propose an accessible and reproducible method for AGB mapping of temperate forests, by combining standard biomass values coming from bibliography and remotely sensed data. This method relies on three steps. (1) The first step consists of produce a map of wooded areas including small woods and isolated trees, and to identify the major forest stands. To do this, we use an unsupervised classification of a Landsat 7 ETM+ image. Results are compared and improved with various land cover data. (2) The second step consists of extract the normalized difference vegetation index (NDVI) values of main forest stands. (3) Finally, these values are combined with standard AGB values provided by bibliography, to calibrate four AGB estimation models of different forest types (broadleaves, coniferous, coppices, and mixed stands). This method provides a map of aboveground biomass for forests and isolated trees with a 30 meters spatial resolution. Results demonstrate that 71 % of AGB values for hardwoods vary between 143 and 363 t.ha-1, i.e. × 1 standard deviation around the average. For coniferous stands, most of values of AGB range from 167 to 256 t.ha-1.

  14. Selection of roosting habitat by forest bats in a diverse forested landscape

    USGS Publications Warehouse

    Perry, R.W.; Thill, R.E.; Leslie, David M.

    2007-01-01

    Many studies of roost selection by forest-dwelling bats have concentrated on microhabitat surrounding roosts without providing forest stand-level preferences of bats; thus, those studies have provided only part of the information needed by managers. We evaluated diurnal summer roost selection by the bat community at the forest-stand level in a diversely forested landscape in the Ouachita Mountains of central Arkansas. Over a 6-year period, we evaluated 428 roost locations for 162 individual bats of 6 species. Using Euclidean distance analysis and individual bat as the experimental unit, all 6 species were selective (P < 0.05) in their choice of roosting habitat. Five of six species preferred (P < 0.05) to roost in or near mature (???50 years old), mixed pine-hardwood forest that had undergone recent partial harvest, midstory removal, and burning; 41.3% of roosts were located in that habitat but it comprised an average of only 22.8% of available habitat. Five of six species also preferred older (???100 years old), relatively unmanaged, mixed pine-hardwood forest. Although 19.9% of roosts from all species were located in 50- to 99-year-old, second-growth forests of mixed pine-hardwood (average of 21.0% of available habitat), that habitat was preferred by no species of bat. In partially harvested stands, unharvested buffer strips (greenbelts) surrounding ephemeral streams were used at differing levels by each species; most (90%) eastern pipistrelle (Pipistrellus subflavus) roosts were in greenbelts whereas few (2.7%) Seminole bat (Lasiurus seminolus) roosts were in greenbelts. Older forests, thinned mature forests with reduced midstories, and greenbelts retained in harvested areas were all important roosting habitats for the bat community in the Ouachita Mountains. Our results demonstrate the importance of open forest conditions and a diversity of stand types to bat communities of the southeastern U.S.

  15. Down-regulation of Slit-Robo pathway mediating neuronal cytoskeletal remodeling processes facilitates the antidepressive-like activity of Gastrodia elata Blume.

    PubMed

    Lin, Shih-Hang; Chen, Wei-Cheng; Lu, Kuan-Hung; Chen, Pei-Ju; Hsieh, Shu-Chen; Pan, Tzu-Ming; Chen, Shui-Tein; Sheen, Lee-Yan

    2014-10-29

    Nowadays, depression is a serious psychological disorder that causes extreme economic loss and social problems. Previously, we discovered that the water extract of Gastrodia elata Blume (WGE) improved depressive-like behavior by influencing neurotransmitters in rats subjected to the forced swimming test. To elucidate possible mechanisms, in the present study, we performed a proteomics and bioinformatics analysis to identify the related pathways. Western blot-validated results indicated that the core protein network modulated by WGE administration was closely associated with down-regulation of the Slit-Robo pathway, which modulates neuronal cytoskeletal remodeling processes. Although Slit-Robo signaling has been well investigated in neuronal development, its relationship with depression is not fully understood. We provide a potential hint on the mechanism responsible for the antidepressive-like activity of WGE. In conclusion, we suggest that the Slit-Robo pathway and neuronal cytoskeleton remodeling are possibly one of the pathways associated with the antidepressive-like effects of WGE.

  16. Radar modeling of a boreal forest

    NASA Technical Reports Server (NTRS)

    Chauhan, Narinder S.; Lang, Roger H.; Ranson, K. J.

    1991-01-01

    Microwave modeling, ground truth, and SAR data are used to investigate the characteristics of forest stands. A mixed coniferous forest stand has been modeled at P, L, and C bands. Extensive measurements of ground truth and canopy geometry parameters were performed in a 200-m-square hemlock-dominated forest plot. About 10 percent of the trees were sampled to determine a distribution of diameter at breast height (DBH). Hemlock trees in the forest are modeled by characterizing tree trunks, branches, and needles as randomly oriented lossy dielectric cylinders whose area and orientation distributions are prescribed. The distorted Born approximation is used to compute the backscatter at P, L, and C bands. The theoretical results are found to be lower than the calibrated ground-truth data. The experiment and model results agree quite closely, however, when the ratios of VV to HH and HV to HH are compared.

  17. Boreal Forest Ecosystems Along Canadian Transect in Central Canada:Multivariate Analysis of Species Composition, Detritus and Soil Carbon Data

    NASA Astrophysics Data System (ADS)

    Bhatti, J.; Yu, Z.; Apps, M. J.

    2001-05-01

    The species composition, detritus, and soil data from 97 boreal forest stands along a transect (BFTCS) in central Canada were analyzed using (detrended) (canonical) correspondence analysis to determine the dominant environmental/site variables that differentiate these forest stands. The forests include aspen, jack pine, black spruce and mixed wood stands. Black spruce stands are densely clustered together on understory DCA plot, suggesting that they have consistent understory species composition, such as feathermoss and ericades, whereas aspen stands have most diverse understory species composition (~30 species), mostly shrubs and herbs. Jack pine stands have several characteristic species of reindeer lichens (Cladina spp.), but have rare saplings and seedlings of jack pine. Although climatic variables show large variation along the transect, the CCA results indicate that site conditions are more important in determining species composition and differentiating the stand types. Characteristics of forest floor (duff layer, woody debris, and drainage) appear to be among the most important site variables. The black spruce stands have significantly higher average carbon (C) densities in duff layer (43,530 kg C/ha) than aspen (25,500 kg C/ha) and jack pine stands (19,400 kg C/ha). The thick duff layer in lowland black spruce stands plays an important role in regulating soil temperatures and moistures, and organic-matter decomposition, which in turn affect the ecosystem C dynamics. During forest succession after a stand-replacing disturbance (e.g., fires), tree biomass increases in all stand types as forests recover; however, detritus biomass first decreases and then increases after ~80 years. In all stand types, duff layer thickness increases with stand regrowth ages. Soil C densities show slight decrease with ages in aspen stands, but increase in other stand types. These results indicate the complex C transfer processes among different components (tree biomass, detritus

  18. Forest dynamics after successive spruce budworm outbreaks in mixedwood forests.

    PubMed

    Bouchard, Mathieu; Kneeshaw, Daniel; Bergeron, Yves

    2006-09-01

    In order to assess the long-term spatiotemporal influence of the spruce budworm in sub-boreal mixedwood forests, we studied the effect of three successive outbreaks in a region of western Quebec, Canada. We used dendrochronology to detect past outbreaks in three areas (111-185 ha), based on the recruitment age of balsam fir (Abies balsamea) and on growth patterns of white spruce (Picea glauca), the two main host species of this defoliating insect. We also used a series of aerial photographs taken between 1935 and 2003 to evaluate overstory mortality and post-outbreak succession patterns in these same areas. Individual outbreaks had a spatially homogenous impact on host species throughout the region, but successive outbreaks differed in intensity: the two outbreaks around 1910 and 1980 caused widespread mortality in the overstory, but an outbreak around 1945 had little impact, probably because the forest mosaic had not yet recuperated from the 1910 outbreak. No clear outbreak was detected in the later part of the 19th century. In portions of the study areas where the 1910 outbreak had a major impact, between 36% and 50% of the stands were reoccupied by balsam fir stands in the period up to the 1980 outbreak (cyclic succession), the rest being at least partly replaced by nonhost species such as Betula spp. Changes in forest composition after the 1910 outbreak were mostly associated with upper-slope positions in all study areas. The 1980 outbreak also had a higher impact than earlier outbreaks in lower-slope positions dominated by black spruce (Picea mariana)-balsam fir mixtures. These results suggest that, at the regional scale, the abundance of mature or over-mature balsam fir stands does not determine the outbreak cycle. When an outbreak occurs, however, its impact will be strongly constrained by forest characteristics such as stand composition and structure, which are themselves influenced by previous disturbances and slope position.

  19. Forest dynamics after successive spruce budworm outbreaks in mixedwood forests.

    PubMed

    Bouchard, Mathieu; Kneeshaw, Daniel; Bergeron, Yves

    2006-09-01

    In order to assess the long-term spatiotemporal influence of the spruce budworm in sub-boreal mixedwood forests, we studied the effect of three successive outbreaks in a region of western Quebec, Canada. We used dendrochronology to detect past outbreaks in three areas (111-185 ha), based on the recruitment age of balsam fir (Abies balsamea) and on growth patterns of white spruce (Picea glauca), the two main host species of this defoliating insect. We also used a series of aerial photographs taken between 1935 and 2003 to evaluate overstory mortality and post-outbreak succession patterns in these same areas. Individual outbreaks had a spatially homogenous impact on host species throughout the region, but successive outbreaks differed in intensity: the two outbreaks around 1910 and 1980 caused widespread mortality in the overstory, but an outbreak around 1945 had little impact, probably because the forest mosaic had not yet recuperated from the 1910 outbreak. No clear outbreak was detected in the later part of the 19th century. In portions of the study areas where the 1910 outbreak had a major impact, between 36% and 50% of the stands were reoccupied by balsam fir stands in the period up to the 1980 outbreak (cyclic succession), the rest being at least partly replaced by nonhost species such as Betula spp. Changes in forest composition after the 1910 outbreak were mostly associated with upper-slope positions in all study areas. The 1980 outbreak also had a higher impact than earlier outbreaks in lower-slope positions dominated by black spruce (Picea mariana)-balsam fir mixtures. These results suggest that, at the regional scale, the abundance of mature or over-mature balsam fir stands does not determine the outbreak cycle. When an outbreak occurs, however, its impact will be strongly constrained by forest characteristics such as stand composition and structure, which are themselves influenced by previous disturbances and slope position. PMID:16995632

  20. Forest models: their development and potential applications for air pollution effects research

    SciTech Connect

    Shugart, H.H.; McLaughlin, S.B.; West, D.C.

    1980-01-01

    As research tools for evaluating the effects of chronic air pollution stress, forest simulation models offer one means of integrating forest growth and development data with generalized indices of pollution stress. This approach permits consideration of both the competitive interactions of trees in the forest stand and the influences of the stage of stand development on sensitivity of component species. A review of forest growth models, including tree, stand, and gap models, is provided as a means of evaluating relative strengths, weaknesses, and limits of applicability of representative examples of each type. Data from recent simulations with a gap model of eastern deciduous forest responses to air pollution stress are presented to emphasize the potential importance of competition in modifying individual species' responses in a forest stand. Recent developments in dendroecology are discussed as a potential mechanism for model validation and extended application.

  1. Hurricane Katrina-induced forest damage in relation to ecological factors at landscape scale.

    PubMed

    Wang, Fugui; Xu, Y Jun

    2009-09-01

    Forest stand stability to strong winds such as hurricanes has been found to be associated with a number of forest, soil and topography factors. In this study, through applying geographic information system (GIS) and logit regression, we assessed effects of forest characteristics and site conditions on pattern, severity and probability of Hurricane Katrina disturbance to forests in the Lower Pearl River Valley, USA. The factors included forest type, forest coverage, stand density, soil great group, elevation, slope, aspect, and stream buffer zone. Results showed that Hurricane Katrina damaged 60% of the total forested land in the region. The distribution and intensity of the hurricane disturbance varied across the landscape, with the bottomland hardwood forests on river floodplains most severely affected. All these factors had a variety of effects on vulnerability of the forests to the hurricane disturbance and thereby spatial patterns of the disturbance. Soil groups and stand factors including forest types, forest coverage and stand density contributed to 85% of accuracy in modeling the probability of the hurricane disturbance to forests in this region. Besides assessment of Katrina's damage, this study elucidates the great usefulness of remote sensing and GIS techniques combined with statistics modeling in assessment of large-scale risks of hurricane damage to coastal forests.

  2. Classifying forest productivity at different scales

    SciTech Connect

    Graham, R.L.

    1991-01-01

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

  3. Insect pest management in forest ecosystems

    NASA Astrophysics Data System (ADS)

    Dahlsten, Donald L.; Rowney, David L.

    1983-01-01

    Understanding the role of insects in forest ecosystems is vital to the development of environmentally and economically sound pest management strategies in forestry Most of the research on forest insects has been confined to phytophagous species associated with economically important tree species The roles of most other insects in forest environments have generally been ignored, including the natural enemies and associates of phytophagous species identified as being important In the past few years several investigations have begun to reevaluate the role of phytophagous species responsible for perturbation in forest ecosystems, and it appears that these species may be playing an important role in the primary productivity of those ecosystems Also, there is an increasing awareness that forest pest managers have been treating the symptoms and not the causes of the problems in the forest Many insect problems are associated with poor sites or sites where trees are growing poorly because of crowding As a result, there is considerable emphasis on the hazard rating of stands of trees for their susceptibility to various phytophagous insects The next step is to manipulate forest stands to make them less susceptible to forest pest complexes A thinning study in California is used as an example and shows that tree mortality in ponderosa pine ( Pinus ponderosa) attributable to the western pine beetle ( Dendroctonus brevicomis) can be reduced by commercial thinning to reduce stocking

  4. Energy and CO(2) flux densities above and below a temperate broad-leaved forest and a boreal pine forest.

    PubMed

    Baldocchi, Dennis D.; Vogel, Christoph A.

    1996-01-01

    Fluxes of carbon dioxide, water vapor and energy were measured above and below a temperate broad-leaved forest and a boreal jack pine (Pinus banksiania Lamb.) forest by the eddy covariance method. The aim of the work was to examine differences between the biological and physical processes that control the fluxes of mass and energy over these disparate forest stand types. Carbon and latent heat flux (LE) densities over the temperate broad-leaved forest were about three times larger than those observed over the boreal forest. Available energy was the key variable modulating LE over the temperate broad-leaved forest, whereas LE over the boreal jack pine stand was sensitive to variations in water vapor pressure deficits (VPDs) and available energy. It was also noted that VPDs had different impacts on transpiration rates of the two forest stands. Increasing VPDs forced a negative feedback on jack pine transpiration, whereas transpiration rates of the well-watered broad-leaved forest responded favorably to increasing VPDs. Carbon dioxide flux densities over the broad-leaved forest stand were more sensitive to changes in absorbed photosynthetic photon flux density than those over the boreal forest. The efficiency of CO(2) uptake over the jack pine stand was reduced, in part, because the low leaf area of the stand caused a sizable fraction of available quanta to be absorbed by nonphotosynthetic organs, such as limbs and trunks. Over both forest stands, variations in photosynthetic photon flux density of photosynthetically active radiation (Q(P)) explained only 50 to 60% of the variance of CO(2) exchange rates. Consequently, caution should be exercised when scaling carbon fluxes to regional scales based on unmodified, satellite-derived indices. The more open nature of the boreal jack pine forest caused water vapor, CO(2) and heat fluxes at the forest floor to be a significant component of whole canopy mass and energy exchange rates. About 20 to 30% of net canopy mass and

  5. Characterization and possible origins of isolated douglas fir stands on the Colorado Plateau

    SciTech Connect

    Spence, J.R.

    1995-09-01

    The floristic composition of several isolated stands of Pseudotsuga menziesii on the Colorado Plateau is compared. All occurred between 1700-2000 meters, which was about 300-500 meters below typical lower limits for the species. Most stands showed evidence of reproduction and recruitment. A small widespread group of species existed that was common to all stands, but beta diversity was high. A preliminary analysis of possible origins of the stands suggested that they are relictual from the late Wisconsin or early Holocene. Bird-dispersed species were less prevalent than expected compared with existing high elevation conifer forests. These stands represent important resources for Quaternary research, but are extremely vulnerable to human-caused disturbances. It is recommended that they be provided protection from disturbance through appropriate management activities of the various land management agencies.

  6. Within-stand variability of leaf phenology in deciduous tree species: characterization and ecological implications

    NASA Astrophysics Data System (ADS)

    Delpierre, N.; Cecchini, S.; Dufrêne, E.; Guillemot, J.; Nicolas, M.

    2014-12-01

    The vast majority of phenological studies address questions relative to the spatial or temporal variability of phenological timings integrated at the forest stand (i.e. tree population) scale. Within a forest stand, the inter-individual variability of phenological timings is expected to affect a range of tree functions among which the access to light, the use of carbon and nitrogen reserves, the absorption of minerals and the sensitivity to pathogens. Hence the individual's phenological traits are likely to be strongly selected, resulting in an adaptation of the population to local conditions, as evidenced by latitudinal and altitudinal clines observed in common garden experiments. Studies dedicated to the within-stand variability of the timing of phenophases have to date been mostly designed for contrasting the behaviours of understory versus overstory species or seedlings compared to their adult conspecifics. The few published papers studying the phenological timings among adult conspecifics revealed unclear patterns. We aimed at clarifying the understanding of the within-stand variability of tree phenology of three of the main European deciduous species (Quercus petraea, Quercus robur and Fagus sylvatica) through the analysis of a unique phenological database collected over 44 (28 Oak sites, 16 Beech stands) forest stands at the tree level for 4 years over France. We show that within a forest stand, individual trees have a distinct "phenological identity" resulting in a year to year conservation of (a) the individuals' spring and autumn phenological rankings and (b) the individuals' critical temperature sums required for budburst and senescence. The individual's spring "phenological identity" affects its functioning and, ultimately, its competitive ability: big trees burst earlier. Acknowledging that Angiosperms show low genetic diversity between populations, we show that the between-site variability of critical temperature sums needed for budburst or senescence

  7. Radar detection of flooding beneath the forest canopy - A review

    NASA Technical Reports Server (NTRS)

    Hess, Laura L.; Melack, John M.; Simonett, David S.

    1990-01-01

    Synthetic aperture radar remote sensing is a promising tool for detection of flooding on forested floodplains. The brigtht appearance of flooded forests on radar images results from double-bounce reflections between smooth water surfaces and tree trunks or branches. Enhanced backscattering at L-band has been shown to occur in a wide variety of forest types, including cypress-tupelo swamps, temperate bottomland hardwoods, spruce bogs, mangroves and tropical floodplain forests. Lack of enhancement is a function of both stand density and branching structure. According to models and measurements, the magnitude of the enhancement is about 3 to 10 dB. Steep incidence angles (20-30 deg) are optimal for detection of flooding, since some forest types exhibit bright returns only at steeper angles. P-band should prove useful for floodwater mapping in dense stands, and multifrequency polarimetric analysis should allow flooded forests to be distinguished from marshes.

  8. A Pine Is a Pine and a Spruce Is a Spruce--The Effect of Tree Species and Stand Age on Epiphytic Lichen Communities.

    PubMed

    Bäcklund, Sofia; Jönsson, Mari; Strengbom, Joachim; Frisch, Andreas; Thor, Göran

    2016-01-01

    With an increasing demand for forest-based products, there is a growing interest in introducing fast-growing non-native tree species in forest management. Such introductions often have unknown consequences for native forest biodiversity. In this study, we examine epiphytic lichen species richness and species composition on the trunks of non-native Pinus contorta and compare these to the native Pinus sylvestris and Picea abies in managed boreal forests in northern Sweden across a chronosequence of age classes. Overall, we recorded a total of 66,209 lichen occurrences belonging to 57 species in the 96 studied forest stands. We found no difference in species richness of lichens between stands of P. contorta and P. sylvestris, but stands of P. abies had higher total species richness. However, species richness of lichens in stands of P. abies decreased with increasing stand age, while no such age effect was detected for P. contorta and P. sylvestris. Lichen species composition progressively diverged with increasing stand age, and in 30-year-old stands all three tree species showed species-specific assemblages. Epiphytic lichen assemblages in stands of 30-year-old P. contorta were influenced by greater basal area, canopy closure, and average diameter at breast height, P. abies stands by higher branch density and canopy closure, and stands of P. sylvestris by greater bark crevice depth. Differences in lichen species richness and composition were mainly explained by canopy closure and habitat availability, and the greater canopy closure in mature P. abies stands promoted the colonization and growth of calicioid lichen species. Our results indicate that the non-native P. contorta have similar species richness as the native P. sylvestris. The main difference in lichen species richness and composition is between P. abies and Pinus spp. in managed forests of boreal Sweden. PMID:26799558

  9. A Pine Is a Pine and a Spruce Is a Spruce – The Effect of Tree Species and Stand Age on Epiphytic Lichen Communities

    PubMed Central

    Bäcklund, Sofia; Jönsson, Mari; Strengbom, Joachim; Frisch, Andreas; Thor, Göran

    2016-01-01

    With an increasing demand for forest-based products, there is a growing interest in introducing fast-growing non-native tree species in forest management. Such introductions often have unknown consequences for native forest biodiversity. In this study, we examine epiphytic lichen species richness and species composition on the trunks of non-native Pinus contorta and compare these to the native Pinus sylvestris and Picea abies in managed boreal forests in northern Sweden across a chronosequence of age classes. Overall, we recorded a total of 66,209 lichen occurrences belonging to 57 species in the 96 studied forest stands. We found no difference in species richness of lichens between stands of P. contorta and P. sylvestris, but stands of P. abies had higher total species richness. However, species richness of lichens in stands of P. abies decreased with increasing stand age, while no such age effect was detected for P. contorta and P. sylvestris. Lichen species composition progressively diverged with increasing stand age, and in 30-year-old stands all three tree species showed species-specific assemblages. Epiphytic lichen assemblages in stands of 30-year-old P. contorta were influenced by greater basal area, canopy closure, and average diameter at breast height, P. abies stands by higher branch density and canopy closure, and stands of P. sylvestris by greater bark crevice depth. Differences in lichen species richness and composition were mainly explained by canopy closure and habitat availability, and the greater canopy closure in mature P. abies stands promoted the colonization and growth of calicioid lichen species. Our results indicate that the non-native P. contorta have similar species richness as the native P. sylvestris. The main difference in lichen species richness and composition is between P. abies and Pinus spp. in managed forests of boreal Sweden. PMID:26799558

  10. A Pine Is a Pine and a Spruce Is a Spruce--The Effect of Tree Species and Stand Age on Epiphytic Lichen Communities.

    PubMed

    Bäcklund, Sofia; Jönsson, Mari; Strengbom, Joachim; Frisch, Andreas; Thor, Göran

    2016-01-01

    With an increasing demand for forest-based products, there is a growing interest in introducing fast-growing non-native tree species in forest management. Such introductions often have unknown consequences for native forest biodiversity. In this study, we examine epiphytic lichen species richness and species composition on the trunks of non-native Pinus contorta and compare these to the native Pinus sylvestris and Picea abies in managed boreal forests in northern Sweden across a chronosequence of age classes. Overall, we recorded a total of 66,209 lichen occurrences belonging to 57 species in the 96 studied forest stands. We found no difference in species richness of lichens between stands of P. contorta and P. sylvestris, but stands of P. abies had higher total species richness. However, species richness of lichens in stands of P. abies decreased with increasing stand age, while no such age effect was detected for P. contorta and P. sylvestris. Lichen species composition progressively diverged with increasing stand age, and in 30-year-old stands all three tree species showed species-specific assemblages. Epiphytic lichen assemblages in stands of 30-year-old P. contorta were influenced by greater basal area, canopy closure, and average diameter at breast height, P. abies stands by higher branch density and canopy closure, and stands of P. sylvestris by greater bark crevice depth. Differences in lichen species richness and composition were mainly explained by canopy closure and habitat availability, and the greater canopy closure in mature P. abies stands promoted the colonization and growth of calicioid lichen species. Our results indicate that the non-native P. contorta have similar species richness as the native P. sylvestris. The main difference in lichen species richness and composition is between P. abies and Pinus spp. in managed forests of boreal Sweden.

  11. 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.

  12. Influence of radiocesium transfer and decontamination on ambient dose in Japanese forest environment

    NASA Astrophysics Data System (ADS)

    Kato, Hiroaki; Onda, Yuichi

    2016-04-01

    This study investigated the effect of post-depositional migration of radiocesium and decontamination on ambient dose rate in Japanese forest environment following the Fukushima Dai-ichi Nuclear Power Plant accident. We measured cesium-137 deposition from canopy to forest floor in association with rainfall and litterfall in two coniferous stands (plantation of Japanese cedar) and a deciduous broad-leaved forest stand (oak with red pine). We also measured temporal evolution of ambient dose rate at different height in each forest site. Radiocesium inventory balance in each forest component (e.g., canopy, litter and mineral soil layer) were established to determine causes of the measured changes of ambient dose rate in three forest sites. Furthermore, we assessed influence of forest decontamination (removal of organic layer of forest floor) on spatial pattern of radiocesium at the forest floor and reduction of ambient dose rate.

  13. Taking Stands for Social Justice

    ERIC Educational Resources Information Center

    Lindley, Lorinda; Rios, Francisco

    2004-01-01

    In this paper the authors describe efforts to help students take a stand for social justice in the College of Education at one predominantly White institution in the western Rocky Mountain region. The authors outline the theoretical frameworks that inform this work and the context of our work. The focus is on specific pedagogical strategies used…

  14. 76 FR 38349 - Plan Revision for Colville, and the Okanogan-Wenatchee National Forests, Washington (Collectively...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-30

    ..., 1989, and 1990 forest plans. The structural arrangement of vegetation, both vertical and horizontal... habitat. Many changes to forest stand structure have occurred due to disturbances such as uncharacteristic... forest structures have declined with a corresponding increase in area and connectivity of...

  15. 76 FR 315 - Sisters Ranger District; Deschutes National Forest; Oregon; Popper Vegetation Management Project

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-04

    ... and Range 9 east, Willamette Meridian. The project area is managed under the Northwest Forest Plan... proposed action to manage forest fuels and forest stand densities, including areas within a designated... acres). The project area also contains 1,336 acres of Riparian Reserves. The alternatives will...

  16. Biomass in Serbia - potential of beech forests

    NASA Astrophysics Data System (ADS)

    Brasanac-Bosanac, Lj.; Cirkovic-Mitrovic, T.; Popovic, V.; Jokanovic, D.

    2012-04-01

    As for the renewable sources for energy production, biomass from forests and wood processing industry comes to the second place. The woody biomass accounts for 1.0 Mtoe, that is equivalent with 1.0 Mtoe of oil. Due to current evaluations, the greatest part of woody biomass would be used for briquettes and pallets production. As the biomass from forests is increasingly becoming the interest of national and international market, a detailed research on overall potential of woody supply from Serbian forests is required. Beech forests account for 29.4 % of forest cover of Serbia. They also have the greatest standing volume (42.4 % of the overall standing volume) and the greatest mean annual increment (32.3 %)(Bankovic,et.al.2009). Herewith, the aim of this poster is to determine the long-term biomass production of these forests.For this purpose a management unit called Lomnicka reka has been chosen. As these beech forests have similar structural development, this location is considered representative for whole Serbia. DBH of all trees were measured with clipper and the accuracy of 0.01 mm, and the heights with a Vertex 3 device (with accuracy of 0.1 m). All measurements were performed on the fields each 500 m2 (square meters). The overall quantity of root biomass was calculated using the allometric equations. The poster shows estimated biomass stocks of beech forests located in Rasina area. Dates are evaluated using non-linear regression (Wutzler,T.et.al.2008). Biomass potential of Serbian beech forests will enable the evaluation of long-term potential of energy generation from woody biomass in agreement with principles of sustainable forest management. The biomass from such beech forests can represent an important substitution for energy production from fossil fuels (e.g. oil) and herewith decrease the CO2 emissions.

  17. Stand development on reforested bottomlands in the Mississippi Alluvial Valley

    USGS Publications Warehouse

    Twedt, D.J.

    2004-01-01

    Reforestation of bottomland hardwood sites in the southeastern United States has markedly increased in recent years due, in part, to financial incentives provided by conservation programs. Currently > 250,000 ha of marginal farmland have been returned to hardwood forests. I observed establishment of trees and shrubs on 205 reforested bottomlands: 133 sites were planted primarily with oak species (Quercus spp.), 60 sites were planted with pulpwood producing species (Populus deltoides, Liquidambar styraciflua, or Platanus occidentalis), and 12 sites were not planted (i.e., passive regeneration). Although oak sites were planted with more species, sites planted with pulpwood species were more rapidly colonized by additional species. The density of naturally colonizing species exceeded that of planted species but density of invaders decreased rapidly with distance from forest edge. Trees were shorter in height on sites planted with oaks than on sites planted with pulpwood species but within a site, planted trees attained greater heights than did colonizing species. Thus, planted trees dominated the canopy of reforested sites as they matured. Planted species acted in concert with natural invasion to influence the current condition of woody vegetation on reforested sites. Cluster analysis of species importance values distinguished three woody vegetation conditions: (1) Populus deltoides stands (2) oak stands with little natural invasion by other tree species, and (3) stands dominated by planted or naturally invading species other than oaks. Increased diversity on reforested sites would likely result from (a) greater diversity of planted species, particularly when sites are far from existing forest edges and (b) thinning of planted trees as they attain closed canopies.