نتایج جستجو برای: eg percentage of canopy cover

تعداد نتایج: 21181098  

2010
David J. Nowak Eric J. Greenfield

The 2001 National Land Cover Database (NLCD) provides 30-m resolution estimates of percentage tree canopy and percentage impervious cover for the conterminous United States. Previous estimates that compared NLCD tree canopy and impervious cover estimates with photo-interpreted cover estimates within selected counties and places revealed that NLCD underestimates tree and impervious cover. Based ...

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...

Density and diversity of birds in two different forest zones, namely, Shasta Kalateh Protected Forest and Alangdareh Recreational Forest, were estimated and compared. Birds and environmental variables were recorded within 25 m radius in 100 sampling points. The first axis of Canonical Component Analysis segregated two main groups of birds. The first group consisted of Black Woodpecker, Great Sp...

The purpose of this study was to investigate some environmental factors of Zagros forest dieback. In this regard, raster layers of elevation, slope, aspect, hillshade, toposhape and the land formation of Zagros forests in Ilam province were prepared. The distribution map of live and dieback forest cover were also prepared, using Landsat 8 panchromatic images. Then, the percentage of dieback for...

The Nearest Individual Sampling Method is one of the distance sampling methods for estimating density, canopy cover and height of forest stands. Some distance sampling methods have more than one density estimator that may be skewed to the spatial pattern. Unless the stands of the trees under study have a random spatial pattern. Therefore, the purpose of this study was evaluating the effect of s...

Risks assessment of forest project implementation in spatial density changes of forest under canopy vegetation using artificial neural network modeling approach   Nowadays, environmental risk assessment has been defined as one of the effective in environmental planning and policy making. Considering the position and structure of vegetation on the forest floor, the main role of forest under ca...

Journal: :مرتع و آبخیزداری 0
محمد جعفری استاد دانشکدة منابع طبیعی دانشگاه تهران محمد طهمورث دانشجوی دکتری تخصصی آبخیزداری دانشکدة منابع طبیعی دانشگاه تهران محسن نقیلو کارشناس ارشد مرکز تحقیقات بین المللی بیابان دانشگاه تهران

the purpose of this research is investigation of relationship between vegetation cover and soil characteristics and determination of the most important soil factor that effects on quantity variations and kinds of vegetation cover in the study area. the study area is located in west of tehran province and south eastern of hashtgerd, next to najm-abad village. after field study, the index vegetat...

The protection and improvement of natural resources especially for desert vegetation need a comprehensive recognition of natural resources and relationship on Soil characteristics. One of the most important species growing in sabzevar desert is Stipagrostis pennata and in the current research the relationship between the physicochemical properties of the soils and growth characteristics of the ...

Journal: :journal of rangeland science 2013
leila darvishi mohammad ali zare chahouki mohammad jafari hussein azarnivand majid yousefi valikchali

growth and productivity of plants are mainly affected by various environmentalfactors in different ecosystems and natural habitat in the world. this research aims to studythe existing relationships between the phytosociology characteristics of thymuskotschyanus and environmental factors in order to find the most important factorsgoverning development of the species in middle taleghan rangelands...

2007
David woodlands Peterson Peter

Questions: How do fire frequency, tree canopy cover, and their interactions influence cover of grasses, forbs and understorey woody plants in oak savannas and woodlands? Location: Minnesota, USA. Methods: We measured plant functional group cover and tree canopy cover on permanent plots within a long-term prescribed fire frequency experiment and used hierarchical linear modeling to assess plant ...

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