نتایج جستجو برای: average of canopy cover diameter
تعداد نتایج: 21187469 فیلتر نتایج به سال:
چکیده رقابت پذیری معیاری کلیدی برای ارزیابی درجه موفقیت کشورها،صنایع و بنگاهها در میدان های رقابتی سیاسی،اقتصادی و نجاری به حساب می آید.بدین معنی که هر کشور،صنعت یا بنگاهی که از توان رقابتی بالایی در بازارهای رقابتی برخوردار باشد،می توان گفت که از رقابت پذیری بالاتری برخوردار می باشد.در تحقیقات مختلف، رقابت پذیری در سه سطح ملی،صنعت و بنگاه مورد توجه قرار گرفته که در این میان سطح بنگاه از د...
Ecological indicators are needed to evaluate natural biodiversity and to estimate environmental change. I used bird community composition as an environmental indicator to evaluate forest disturbance (at the community level) in areas of Western Mexico. Surveyed bird and vegetation composition data at 79 sites within regions of the Sierra Madre del Sur and Transvolcanic Belt Provinces of Central ...
Forest fragmentation results in a loss of forest interior and an increase in edge habitat. We studied how understorey bird community composition and habitat variables changed along an edge-to-interior gradient in a 1248-ha lowland rainforest patch in peninsular Malaysia. Birds and environmental variables such as vegetation structure and litter depth were detected within a 25-m radius of each of...
Given the importance of availability sufficient and accurate information on the structural characteristics of mangroves to develop conservation and restoration programs for these ecosystems, this study investigates and maps the structural characteristics of the coastal and island forms of the mangroves in the Hara Biosphere Reserve. To this end, through a field inventory (32 sample plots with t...
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...
Mistletoe (Loranthus europaeus Jacq) is an evergreen bush which is considered as a semi-parasitic plant of Ilam forests and show off in late autumn and winter in the northern forest of Ilam. The aim of this study was to investigate the effect of mistletoe on some Quantitative characteristics and nutrient uptake in oak forests (Quercus brantii L.) of Bankol in Ilam Province. For this study,...
In arctic tundra, where wind transport of snow is common, shrubs can significantly modify the distribution and physical characteristics of the snow cover. We examined interactions between shrubs and snow by measuring snow depths along three 1-km transects in arctic Alaska and then measuring plant canopy characteristics at the same locations during the following growing season. Snow depths corre...
Mangrove forests are one of the most productive and carbon dense ecosystems that are only found at tidally inundated coastal areas. Forest canopy height is an important measure for modeling carbon and biomass dynamics, as well as land cover change. By taking advantage of the flat terrain and dense canopy cover, the present study derived digital surface models (DSMs) using stereo-photogrammetric...
In this study, the abundance and biomass of soil macrofauna were investigated in natural forests of tamarisk and Euphrates poplar in riparian forests of Maroon River in Khuzestan province. Soil macrofauna were collected using 175 sampling plots 50 meter distance from each other on 21 parallel lines with 100 meters distance from each other and perpendicular to the river. Soil macrofauna sampling...
The aim of this study was to investigate the role of species of Trifolium genus on the composition, diversity, forage value and quantitative vegetation parameters and interaction between Trifolium species and invasive species Leucanthemum vulgare Lam. in Fandoghlou rangelands in Ardabil province. In determining the sampling locations, six sites by systematic random method and due to the distrib...
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