نتایج جستجو برای: canopy cover percentage

تعداد نتایج: 254028  

2014
Eric Nielsen Matt Noone

We used a predictive model to map canopy cover of vegetation over seven feet in height (“tall woody vegetation”) at 30-meter resolution over nearly 29 million acres within and adjacent to the range of the greater sage-grouse in Oregon (Figure 1). Texture measures computed at various resolutions from colorinfrared aerial photography provided the main source of predictor data used to produce the ...

Journal: :محیط زیست طبیعی 0
جابر شریفی عضو هیئت علمی مرکز تحقیقات کشاورزی و منابع طبیعی استان اردبیل، دانشجوی دورۀ دکتری موسسۀ تحقیقات گیاه شناسی آکادمی ملی علوم آذربایجان. عادل جلیلی استاد پژوهش موسسۀ تحقیقات جنگل ها و مراتع ایران. شاکر قاسم اف استاد پژوهش موسسۀ گیاه شناسی آکادمی ملی علوم جمهوری آذربایجان علیرضا نقی نژاد دانشیار گروه زیست شناسی، دانشکده علوم پایه، دانشگاه مازندران، بابلسر علی اکبر ایمانی استادیارگروه گشاورزی و گیاهان دارویی دانشگاه اسلامی آزاد اسلامی واحد اردبیل

the current study aims to ordinate ecological groups in the wetlands of northern and eastern slopes of the sabalan mountain and investigate their relationship with environmental variables. the location of wetlands was found using field surveys and satellite images. in total, 32 wetland sites were identified for the sampling purpose. 320 sample plots (relevé) were selected using the systematic-r...

2002
Janet Franklin Frank W. Davis Paul Lefebvre

T h e effect of variable tree canopy cover, shadows, and topography on Thematic Mapper (TM) data was examined for blue oak (Quercus douglasii) woodland and wooded grassland on rugged terrain in central California. Thematic Mapper data were analyzed from September 1986 (trees in leaf, grass understory senescent) and December 1984 (trees leafless, grasses emerging. Tree cover measured in 84 60 m ...

اکبرلو, موسی , بهره مند, عبدالرضا, جعفری فوتمی, عیسی, نیک نهاد قرماخر, حمید,

After the destructive floods in Golestan Province during the early seventies, numerous biomechanical practices were performed in order to the restoration of vegetation cover and affecting the runoff in the main cluster of Gorganrood river, so the extensive studies are necessaire for the evaluation of their results. The goal of this study was to evaluate the changes in some physicochemical prope...

2012
JENNIFER E. HESS

Wyoming big sagebrush (Artemisia tridentata wyomingensis) treatments are often implemented to improve breeding habitat for greater sage-grouse (Centrocercus urophasianus), a species of considerable conservation concern. In 2008 and 2009, we measured vegetation structure available to sage-grouse for breeding at 19 sites that were prescribed burned during 1990–1999 and 2000–2006, 6 sites that wer...

Vegetative characteristics of plant species are strongly dependent on habitat environmental conditions. Most Salt cedar (Tamarix ramosissima) individuals grow on unsuitable soil and climate conditions. One of the important habitats of this species is near Abyaneh in Isfahan Province. To investigate the relation of edaphic factors on the growth of T. ramosissima, three plots 400m2 in area were r...

2017
Scott R. Abella

–Trees in many forests affect the soils and plants below their canopies. In current high-density southwestern ponderosa pine (Pinus ponderosa) forests, managers have opportunities to enhance multiple ecosystem values by manipulating tree density, distribution, and canopy cover through tree thinning. I performed a study in northern Arizona ponderosa pine-Gambel oak (Quercus gambelii) forests to ...

2012
John W. Coulston Gretchen G. Moisen Barry T. Wilson Mark V. Finco Warren B. Cohen

0099-1112/12/7807–715/$3.00/0 © 2012 American Society for Photogrammetry and Remote Sensing Abstract Tree canopy cover is a fundamental component of the landscape, and the amount of cover influences fire behavior, air pollution mitigation, and carbon storage. As such, efforts to empirically model percent tree canopy cover across the United States are a critical area of research. The 2001 nation...

2012
Nelson Valdivia Claire Golléty Aline Migné Dominique Davoult Markus Molis

The temporal stability of aggregate community properties depends on the dynamics of the component species. Since species growth can compensate for the decline of other species, synchronous species dynamics can maintain stability (i.e. invariability) in aggregate properties such as community abundance and metabolism. In field experiments we tested the separate and interactive effects of two stre...

2004
Malcolm North Jiquan Chen Brian Oakley Bo Song Mark Rudnicki Andrew Gray Jim Innes

With fire suppression, many western forests are expected to have fewer gaps and higher stem density of shade-tolerant species as light competition becomes a more significant influence on stand pattern and composition. We compared species composition, structure, spatial pattern, and environmental factors such as light and soil moisture between two old-growth forests: Pacific Northwest western he...

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