نتایج جستجو برای: vegetation cover density and type
تعداد نتایج: 17062927 فیلتر نتایج به سال:
vegetation cover on a variety of different land uses in different parts of a city creates different forms of heat flow that this, in turn, generates the main framework of urban microclimate. the objective of this study is to survey the effect of land cover type on air temperature in the isfahan city. to do this, five regions in the isfahan city with different land cover type were selected. in e...
The vegetation cover and rangeland production are the most important factors to determine the proper planning system for effective utilization and management of rangelands. In this research, the effect of climatic factors (temperature and rainfall) were studied on vegetation cover and forage production of four species (Festuca ovina, Bromus tomentellus, Dactylis glomerata and Agropyron trichoph...
rangelands encompass 55% of iran's territory. monitoring of such resources is inevitable due to dynamic behavior and extremely high extension. scanning of land resources data by satellites facilitates monitoring the rangelands. this research was carried out to study the relationships of vegetation indices derived from irs liss-iii data with vegetation cover of tange sayyad region in the ch...
in this study, the effects of oleothermal modification on physical and mechanical peroperties of fir wood (abeis sp.) blocks were examined. at first, some blocks of fir wood with 5 × 20 × 120 cm dimensions were prepared. the blocks were treated in soybean oil. the effects of 3 factors such as treatments temperature (180and 200 °c), holding time (12 and 15 h) and initial moisture content of wood...
Habitat loss and chytridiomycosis (a disease caused by the chytrid fungus Batrachochytrium dendrobatidis - Bd) are major drivers of amphibian declines worldwide. Habitat loss regulates host-pathogen interactions by altering biotic and abiotic factors directly linked to both host and pathogen fitness. Therefore, studies investigating the links between natural vegetation and chytridiomycosis requ...
Long-term studies can broaden our ecological understanding and are particularly important when examining contingent effects that involve changes to dominance by long-lived species. Such a change occurred during the last century in Southwestern (USA) ponderosa pine (Pinus ponderosa) forests. We used five livestock grazing exclosures established in 1912 to quantify vegetation structure in 1941 an...
The desirable structure of longleaf pine forests, which generally includes a relatively open canopy of pines, very few woody stems in the mid-story, and a well-developed, herbaceous ground layer, provides critical habitat for flora and fauna and contributes to ecosystem function. Current efforts to restore longleaf pine to upland sites dominated by second-growth loblolly pine require informatio...
Medicinal plant species constitute a considerable part of the flora in Iran and play a major role in the composition of plant communities. Therefore, it is necessary to recognize the factors leading to the establishment and distribution of vegetation. For data sampling (2012), land units were specified. The plot size was determined using minimal area method and number of plots was determined by...
this study aims to assess the effect of grazing intensity on vegetation structure, soil nutrient concentrations and soil physical properties. the study was carried out in steppe rangelands of saveh, markazi province, iran. four sites with four grazing intensities including very high, high, moderate and non-grazed with the same ecological conditions were selected. to study various vegetation and...
We present a methodology to detect terrain mobilization in the years following a fire using multitemporal Landsat TM imagery. Furthermore, we show the spectral evolution of the land cover since fire occurrence, and analyze the feasibility of detecting the type of land cover a number of years after fire occurrence. The methodology developed here is a spectral change identification technique base...
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