The Experts below are selected from a list of 29574 Experts worldwide ranked by ideXlab platform
Susumu Yamamoto - One of the best experts on this subject based on the ideXlab platform.
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Examination of model‐estimated ecosystem respiration using flux measurements from a cool‐temperate deciduous broad‐leaved Forest in central Japan
Tellus B: Chemical and Physical Meteorology, 2007Co-Authors: Akihiko Ito, Motoko Inatomi, Mi Sun Lee, Hiroshi Koizumi, Nobuko Saigusa, Shohei Murayama, Susumu YamamotoAbstract:Reducing uncertainty in the emission of carbon dioxide (CO 2 ) from plants and microbes is critically important in determining carbon budgets. We examined properties of net ecosystem CO 2 exchange ( NEE ) derived from a process-based model that simulates an ecosystem carbon cycle, focusing on nighttime flux determined from ecosystem respiration and soil efflux. The model simulated autotrophic and heterotrophic respiration using semi-empirical ecophysiological parameterizations. In a cool-temperate deciduous Broad-Leaved Forest in central Japan, simulation results from 1998 to 2005 were compared with measurement of the Forest made using eddy-covariance and chamber methods. The model estimated annual ecosystem respiration as 1397 g Cm -2 yr -1 , of which 67% was from the soil surface, with a clear seasonal cycle. Compared to flux observations, the model appropriately captured daytime NEE , but produced substantial differences from the observed nighttime NEE . The differences were evident under stable atmospheric conditions (at low friction velocity), implying a problem with the observations. With regard to soil-surface CO 2 efflux (soil respiration), the model estimation was consistent with chamber observations, except in winter periods with thick snow cover. We discuss whether the model is applicable for estimating ecosystem respiration rates, and what is required to improve the predictability of the model. DOI: 10.1111/j.1600-0889.2007.00258.x
Shunzhong Wang - One of the best experts on this subject based on the ideXlab platform.
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Coarse woody debris features of a warm temperate deciduous Broad-Leaved Forest, northern China
Journal of Forestry Research, 2020Co-Authors: Liwen Zhuang, Shunzhong Wang, Weiguo SangAbstract:Stocking and structural composition of a deciduous Broad-Leaved Forest were determined to predict coarse woody debris quantity by quantifying the empirical relationships between these two attributes. The most ecologically significant families by stem density were Salicaceae, Betulaceae, Fagaceae, and Aceraceae. Populus davidiana was the most dominant species followed by Betula dahurica, Quercus mongolica, and Acer mono. The four species accounted for 69.5% of total stems. Numerous small-diameter species characterized the coarse woody debris showing a reversed J-shaped distribution. The coarse debris of P. davidiana, B. dahurica, and Q. mongolica mainly comprised the 10–20 cm size class, whereas A. mono debris was mainly in the 5–10 cm size class. The spatial patterns of different size classes of coarse woody debris were analyzed using the g-function to determine the size of the tree at its death. The results indicate that the spatial patterns at the 0–50 m scale shifted gradually from an aggregated to a random pattern. For some species, the larger coarse debris might change from an aggregated to a random distribution more easily. Given the importance of coarse woody debris in Forest ecosystems, its composition and patterns can improve understanding of community structure and dynamics. The aggregation pattern might be due to density dependence and self-thinning effects, as well as by succession and mortality. The four dominant species across the different size classes showed distinct aggregated distribution features at different spatial scales. This suggests a correlation between the dominant species population, size class, and aggregated distribution of coarse woody debris.
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species spatial distributions in a warm temperate deciduous broad leaved Forest in china
Journal of Forestry Research, 2020Co-Authors: Shunzhong WangAbstract:Spatial distribution is fundamental for understanding species coexistence mechanisms in Forest communities. Here we comprehensively explored fine-scale spatial patterns of tree species in a secondary warm-temperate deciduous Broad-Leaved Forest community in north China. Aggregated distribution patterns were predominant. Species functional traits had no significant effects on their spatial patterns. The aggregation intensity decreased with increasing DBH and abundance. The multivariate linear stepwise regression showed that abundance and maximum DBH were correlated with the aggregation intensity. Our results partially confirm that species attributes (abundance, DBH) and habitat heterogeneity may primarily contribute to spatial patterns and species coexistence in this secondary Forest.
Wen-yao Liu - One of the best experts on this subject based on the ideXlab platform.
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Nutrient budget of a montane evergreen broad‐leaved Forest at Ailao Mountain National Nature Reserve, Yunnan, southwest China
Hydrological Processes, 2003Co-Authors: Wen-yao Liu, John E. D. FoxAbstract:Hydrological fluxes and associated nutrient budget were studied during a 2 year period (1998–99) in a montane moist evergreen Broad-Leaved Forest at Ailao Mountain, Yunnan. Water samples of rainfall, throughfall, and stemflow, and of surface runoff, soil water, and stream flow were collected bimonthly to determine the concentration and fluxes of nutrients. Soil budgets were determined from the difference between precipitation input (including nutrient leaching from canopy) and output via runoff and drainage. The Forest was characterized by low canopy interception and surface runoff, and high percolation and stream flow. Concentrations of nutrients were increased in throughfall and stemflow compared with precipitation. Surface runoff and drainage water had higher nutrient concentrations than precipitation and stream water. Total nitrogen and NH4+-N concentrations were higher in soil water than stream water, whereas K+, Ca2+, and Mg2+ concentrations were lower in the former than the latter. Annual nutrient fluxes decreased with soil depth following the pattern of water flux. Annual losses of most nutrient elements via stream flow were less than the corresponding inputs via throughfall and stemflow, except for calcium, for which solute loss was greater than the inputs via precipitation. Leaching losses of that element may be compensated by weathering. Losses of nitrogen, phosphorus, potassium, magnesium, sodium, and sulphur could be replaced through atmospheric inputs. Copyright © 2002 John Wiley & Sons, Ltd.
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nutrient budget of a montane evergreen broad leaved Forest at ailao mountain national nature reserve yunnan southwest china
Hydrological Processes, 2003Co-Authors: Wen-yao Liu, John E. D. FoxAbstract:Hydrological fluxes and associated nutrient budget were studied during a 2 year period (1998–99) in a montane moist evergreen Broad-Leaved Forest at Ailao Mountain, Yunnan. Water samples of rainfall, throughfall, and stemflow, and of surface runoff, soil water, and stream flow were collected bimonthly to determine the concentration and fluxes of nutrients. Soil budgets were determined from the difference between precipitation input (including nutrient leaching from canopy) and output via runoff and drainage. The Forest was characterized by low canopy interception and surface runoff, and high percolation and stream flow. Concentrations of nutrients were increased in throughfall and stemflow compared with precipitation. Surface runoff and drainage water had higher nutrient concentrations than precipitation and stream water. Total nitrogen and NH4+-N concentrations were higher in soil water than stream water, whereas K+, Ca2+, and Mg2+ concentrations were lower in the former than the latter. Annual nutrient fluxes decreased with soil depth following the pattern of water flux. Annual losses of most nutrient elements via stream flow were less than the corresponding inputs via throughfall and stemflow, except for calcium, for which solute loss was greater than the inputs via precipitation. Leaching losses of that element may be compensated by weathering. Losses of nitrogen, phosphorus, potassium, magnesium, sodium, and sulphur could be replaced through atmospheric inputs. Copyright © 2002 John Wiley & Sons, Ltd.
John E. D. Fox - One of the best experts on this subject based on the ideXlab platform.
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Nutrient budget of a montane evergreen broad‐leaved Forest at Ailao Mountain National Nature Reserve, Yunnan, southwest China
Hydrological Processes, 2003Co-Authors: Wen-yao Liu, John E. D. FoxAbstract:Hydrological fluxes and associated nutrient budget were studied during a 2 year period (1998–99) in a montane moist evergreen Broad-Leaved Forest at Ailao Mountain, Yunnan. Water samples of rainfall, throughfall, and stemflow, and of surface runoff, soil water, and stream flow were collected bimonthly to determine the concentration and fluxes of nutrients. Soil budgets were determined from the difference between precipitation input (including nutrient leaching from canopy) and output via runoff and drainage. The Forest was characterized by low canopy interception and surface runoff, and high percolation and stream flow. Concentrations of nutrients were increased in throughfall and stemflow compared with precipitation. Surface runoff and drainage water had higher nutrient concentrations than precipitation and stream water. Total nitrogen and NH4+-N concentrations were higher in soil water than stream water, whereas K+, Ca2+, and Mg2+ concentrations were lower in the former than the latter. Annual nutrient fluxes decreased with soil depth following the pattern of water flux. Annual losses of most nutrient elements via stream flow were less than the corresponding inputs via throughfall and stemflow, except for calcium, for which solute loss was greater than the inputs via precipitation. Leaching losses of that element may be compensated by weathering. Losses of nitrogen, phosphorus, potassium, magnesium, sodium, and sulphur could be replaced through atmospheric inputs. Copyright © 2002 John Wiley & Sons, Ltd.
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nutrient budget of a montane evergreen broad leaved Forest at ailao mountain national nature reserve yunnan southwest china
Hydrological Processes, 2003Co-Authors: Wen-yao Liu, John E. D. FoxAbstract:Hydrological fluxes and associated nutrient budget were studied during a 2 year period (1998–99) in a montane moist evergreen Broad-Leaved Forest at Ailao Mountain, Yunnan. Water samples of rainfall, throughfall, and stemflow, and of surface runoff, soil water, and stream flow were collected bimonthly to determine the concentration and fluxes of nutrients. Soil budgets were determined from the difference between precipitation input (including nutrient leaching from canopy) and output via runoff and drainage. The Forest was characterized by low canopy interception and surface runoff, and high percolation and stream flow. Concentrations of nutrients were increased in throughfall and stemflow compared with precipitation. Surface runoff and drainage water had higher nutrient concentrations than precipitation and stream water. Total nitrogen and NH4+-N concentrations were higher in soil water than stream water, whereas K+, Ca2+, and Mg2+ concentrations were lower in the former than the latter. Annual nutrient fluxes decreased with soil depth following the pattern of water flux. Annual losses of most nutrient elements via stream flow were less than the corresponding inputs via throughfall and stemflow, except for calcium, for which solute loss was greater than the inputs via precipitation. Leaching losses of that element may be compensated by weathering. Losses of nitrogen, phosphorus, potassium, magnesium, sodium, and sulphur could be replaced through atmospheric inputs. Copyright © 2002 John Wiley & Sons, Ltd.
Kerstin Wiegand - One of the best experts on this subject based on the ideXlab platform.
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spatial distribution and association patterns in a tropical evergreen broad leaved Forest of north central vietnam
Journal of Vegetation Science, 2016Co-Authors: Hong Hai Nguyen, Jaime Uriadiez, Kerstin WiegandAbstract:Questions What are the prevailing types of intraspecific spatial distributions and interspecific association patterns at species and life stage levels of trees in a tropical rain Forest? Which ecological processes could structure these patterns? Possible processes include dispersal limitation, self-thinning, facilitation and competition between species and life stages. Location A tropical Broad-Leaved Forest in north-central Vietnam. Methods We used univariate and bivariate pair-correlation functions to investigate the spatial distribution and association patterns of 18 abundant tree species. To disentangle first- and second-order effects, we used a scale separation approach with the heterogeneous Poisson process as null model. Results (1) Sixteen of 18 species had aggregated patterns at various scales and regardless of their abundance. (2) Significant and aggregated patterns were found in 64% of all specific life stages. (3) At scales up to 15 m, 12.4% species pairs showed significant associations, among that 71% were spatial attractions, 5% were spatial repulsions and 24% were non-essential interactions. (4) In different life stage associations, attractions (81%) predominated over repulsions (19%) at small scales of up to 15 m. Conclusions Our findings provide evidence that dispersal limitation may regulate the spatial patterns of tree species. Moreover, positive spatial associations between tree species and life stages suggest the presence of species herd protection and/or facilitation in this Forest stand, while the persistence of intraspecific aggregation through life stages suggests a very late onset or even absence of self-thinning. Habitat heterogeneity plays an important role for species distribution patterns, and the spatial segregation occurs at a scale around 15 m in this Forest.
