نتایج جستجو برای: forest structure
تعداد نتایج: 1663160 فیلتر نتایج به سال:
Forest management under a changing climate requires assessing the effects of climate warming and disturbance on the composition, age structure, and spatial patterns of tree species. We investigated these effects on a boreal forest in northeastern China using a factorial experimental design and simulation modeling. We used a spatially explicit forest landscape model (LANDIS) to evaluate the effe...
The ‘Community Forestry Program’ has been considered successful in improving the environmental situation in the hills of Nepal by enhancing the vegetation coverage of degraded sites and by improving the supply of forest products to farmers. The restoration measures are considered sustainable if the ecosystems are self-supporting and resilient against perturbation. A community forest (CF) in the...
In light of an anticipated shift in timber extraction that focuses on non-pine forest types in the Northern Interior forest region, the evaluation of new remote sensing tools in these areas provide an important opportunity to examine methods, models and processes for improved inventories and resource analyses. This report summarizes the application of the LiDAR system to estimate understory veg...
The Lowland Forest is one of the most disturbed and fragile ecosystems in the Atlantic Forest biome, yet little is known regarding its successional trajectory and resilience. We evaluated changes in species assemblages and forest structure of the canopy and understory along a successional gradient (young 21-yrs old forest, immature 34-yrs old forest and late successional 59-yrs old forest) aimi...
We investigated whether fish assemblage structure in southern Appalachian streams differed with historical and contemporary forest cover. We compared fish assemblages in 2(nd)-4(th) order streams draining watersheds that had increased forest cover between 1950 and 1993 (i.e., reforesting watersheds). We sampled fish in 50 m reaches during August 2001 and calculated catch-per-unit-effort (CPUE) ...
abstract: the present thesis includes ; one preface and 11speeches , that each speech considered in different researches . the prefact part , studied grammer back ground , the first speech considered a brief description about grammatical credits . the second speech considered the different typs of sentences , from structure and meaning points of view . the third speech considered the verb es...
Information about how vegetation composition and structure vary quantitatively and spatially with physical environment, disturbance history, and land ownership is fundamental to regional conservation planning. However, current knowledge about patterns of vegetation variability across large regions that is spatially explicit (i.e., mapped) tends to be general and qualitative. We used spatial pre...
Forest structure consider the spatial arrangement of trees characteristics such as age, size, species, gender and so on is.This study aimed to investigate the structural diversity of three one-hectare stands in the gap making phase, were studied. For this purpose, three sample plots with a one hectare area were selected in Asalem beech stands which belonged to the structural features of the gap...
The quantitative description of forest structure can be regarded as one of the most usable working tools in modern forest management.The study aims at analyzing the stand structure in unlogged beech forests using nearest neighbor indices. Data collection was done in compartment 319 with an area about 48 ha in Educational and Experimental Forests of University of Tehran. Species and DBH of all ...
Changes in the frequency, duration, and severity of climate extremes are forecast to occur under global climate change. The impacts of climate extremes on forest productivity and health remain difficult to predict due to potential interactions with disturbance events and forest dynamics-changes in forest stand composition, density, size and age structure over time. Such interactions may lead to...
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