نتایج جستجو برای: Forests
تعداد نتایج: 39403 فیلتر نتایج به سال:
in order to examine the ecological conditions and characteristics of fraxinus excelsior l. in the northern forests of iran 6 main areas as well as some miscellaneous ones , have been selected in the region respectively in : lomir2, shafaroud , park - e-noor , ahlam , alandan and noor.
the assessment of the quantitative and qualitative changes, the result of the impacts imposed by natural factors, and human interventions during specific sampling periods has a substantial influence on nature, management method and tending operation of every region’s forests. the present research was carried out in golestan province forests (iran) over an 11- year period and the obtained statis...
conclusions the crude extract of streptomyces sp. acs52 had high antibacterial activity against a wide spectrum of bacteria and could be of interest due to its features such as ability to grow at low temperatures and alkaline ph levels. results streptomyces sp. acs52 is a cold-resistant alkalophilic bacterium strain with antibacterial activity against a broad spectrum of pathogenic bacteria. th...
The assessment of the quantitative and qualitative changes, the result of the impacts imposed by natural factors, and human interventions during specific sampling periods has a substantial influence on nature, management method and tending operation of every region’s forests. The present research was carried out in Golestan province forests (Iran) over an 11- year period and the obtained statis...
in order to investigate the effects of management models on the diversity of wooden species, forests of third series of shiler, the first division mehrbanrud watershed and third and fourth series of eight division of behshahr – neka townships were studied with participatory and governmental management respectively. the diversity of the wooden species have been evaluated by diversity parametric...
در این مطالعه، تعداد زیادی نمونه درختی از رویشگاه های مختلف و نمونه های هرباریومی مورد مطالعه قرار گرفت. مشکلات تاکسونومیک فراوانی در رابطه با شناسایی گونه های جنس نمدار در ایران وجود دارد، نتایج مطالعات تعدادی از گیاه شناسان بر روی این جنس، تنها نمایانگر حضور گونه tilia platyphyllos و در مطالعات برخی گونه tilia dasystyla و در تعدادی هم گونه tilia rubra در ایران است. در واقع نتایج مطالعات اکث...
Mapping of forest extent is a prerequisite to acquire quantitative and qualitative information about forests and to formulate management and conservation strategies. forest canopy density (FCD) model is one of the useful RS methods for forest mapping using satellite images. One of the most serious challenges in FCD model is the weakness in the calculation of canopy density in low density forest...
Trees with sufficient nutrition are known to allocate carbon preferentially to aboveground plant parts. Our global study of 49 forests revealed an even more fundamental carbon allocation response to nutrient availability: forests with high-nutrient availability use 58 ± 3% (mean ± SE; 17 forests) of their photosynthates for plant biomass production (BP), while forests with low-nutrient availabi...
Most studies on frugivorous bat assemblages in secondary forests have concentrated on differences among successional stages, and have disregarded the effect of forest management. Secondary forest management practices alter the vegetation structure and fruit availability, important factors associated with differences in frugivorous bat assemblage structure, and fruit consumption and can therefor...
PRIMARY TROPICAL FORESTS ARE POWERhouses of biodiversity (1) but are rapidly declining in extent and are threatened even within some protected areas (2). As a result, non-primary forests, especially those that have been selectively logged, are becoming more important to conservation efforts. In the tropics, logging is almost always selective, targeting only certain commercially valuable tree sp...
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