نتایج جستجو برای: natural forest
تعداد نتایج: 576922 فیلتر نتایج به سال:
-The avian community of a mature residential area was studied and compared with an undisturbed climax beech-maple forest. Urbanization was presumed to be responsible for decreasing species richness and diversity, increasing biomass and density, and favoring dominance by a few species. Foraging guilds shifted from forest insectivores that were canopy foliage gleaners or bark drillers to urban gr...
In many temperate terrestrial forest ecosystems, both natural human disturbances drive the reestablishment of forests. Succession in plant communities, in addition to reforestation following the creation of open sites through harvesting or natural disturbances, can affect forest faunal assemblages. Wild bees perform an important ecosystem function in human-altered and natural or seminatural eco...
a Department of Forest Engineering Resources and Management, College of Forestry, Oregon State University, Corvallis, OR 97331, USA b Pacific Forestry Centre, Canadian Forest Service, Natural Resources Canada, Victoria, British Columbia V8Z 1M5, Canada c Integrated Remote Sensing Studio, Department of Forest Resources Management, University of British Columbia, Vancouver, British Columbia V6T 1...
the present study was carried out during a one year period in 2012-2013 in order to investigation of seasonal density and diversity of diplopoda in a hyrcanian forest (semeskandeh forest) in northern iran. for these purpose, some forest soil sampling were done in two mounth intervals and the samples were collected from leaf litter (ol,f,h), the 0-3 cm and 3-6 cm of soil layer (ah). a total of 7...
quantifying spatial structure is one of the most important components, describing natural ecosystems and their biodiversity. in this study, a set of indices and functions related to spatial structure using 102 established plots with an area of 1000 m2 were presented. to achieve spatial structure of carpinus-fagus type, a set of indices (clark & evans, uniform angle, shannon-wiener, mingling and...
Patrick C. Tobin*, Barry B. Bai, Donald A. Eggen and Donna S. Leonard Forest Service, United States Department of Agriculture, Northern Research Station, Morgantown, West Virginia 26505, USA; Oregon Department of Agriculture, Plant Division, Salem, Oregon 97301, USA; Pennsylvania Department of Conservation and Natural Resources, Bureau of Forestry, Division of Forest Pest Management, Middletown...
15 The endemic pine, Pinus canariensis, forms one of the main forest ecosystems in the 16 Canary Islands. In this archipelago, pine forest is a mosaic of natural stands (remnants 17 of past forest overexploitation) and artificial stands planted from the 1940’s. The 18 genetic makeup of the artificially regenerated forest is of some concern. The use of 19 reproductive material with uncontrolled ...
However, in 1988 the National Forest Policy heralded a significant shift in forest policy by acknowledging the needs and interests of local communities concerning their utilization of forest resources, and involving them in the protection and regeneration of forests. However, deforestation and violation of local community interests continued, due to the conflict between conserving endangered na...
Studies of the history and current status of forest resources in Northeast China have become important in discussions of sustainable forest management in the region. Prior to 1998, excessive logging and neglected cultivation led to a series of problems that left exploitable forest reserves in the region almost exhausted. A substantial decrease in the area of natural forests was accompanied by s...
عملکردهای زیستی پروتئین ها به واکنش های شیمیایی آنها با محیط پیرامون و سایر پروتئین ها بستگی دارد. به عبارت دیگر، ساختار سه بعدی و نحوه تاخوردن اجزای پروتئین ها در فضا، چگونگی این تعاملات را تعیین می کند. تشخیص صحیح الگوی تاخوردگی پروتئین با استفاده از اطلاعات استخراج شده از توالی آن، یکی از مسائل پیچیده و بحث برانگیز در زمینه بیوانفورماتیک می باشد. در این پایان نامه، سه روش نوین مبتنی بر الگور...
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