نتایج جستجو برای: aspen dynamic
تعداد نتایج: 408689 فیلتر نتایج به سال:
Quaking aspen (Populus tremuloides) is commonly believed to be declining throughout western North America. Using a historical vegetation map and Landsat TM5 imagery, this study detects changes in regional aspen cover over two different time periods of 85 and 18 years and examines aspen change patterns with biophysical variables in the Targhee National Forest of eastern Idaho, USA. A subpixel cl...
Forest structural heterogeneity due to species composition, spatial relationships and tree size are widely studied patterns in forest systems, but their impacts on tree function are not as well documented. The objective of this study was to examine how stand composition, tree proximity relationships and tree size influence the leaf functional traits of aspen, an early successional species, and ...
Trembling aspen (Populus tremuloides Michx.) generally grows as clones in which stems, ranging from many thousands to only a few, are interconnected by a common root system. When clones are very large, in one recorded case involving about 47␣ 000 stems joined together over a 43 ha area, aspen becomes a candidate for earth’s most massive and oldest organism. Recent analyses suggest that aspen cl...
Question: Can lichen communities be used to assess shortand long-term factors affecting seral quaking aspen (Populus tremuloides) communities at the landscape scale? Location: Bear River Range, within the Rocky Mountains, in northern Utah and southern Idaho, USA. Method: Forty-seven randomly selected mid-elevation aspen stands were sampled for lichens and stand conditions. Plots were characteri...
1 Corresponding author: [email protected]; 715-346-4098 2 [email protected]; 541-737-3056 ABSTRACT: Aspen (Populus tremuloides) stands inside and outside Yellowstone National Park (YNP), Wyoming, USA, were compared to test whether the lack of overstory aspen recruitment observed in YNP extended to winter ranges of elk (Cervus elaphus) in adjacent national forests. Remote sensing and fi...
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We conducted an analysis of aspen (Populus tremuloides) overstory recruitment on the northern range of Yellowstone National Park (YNP) using information provided in a monograph published by Warren (Warren, E.R., 1926. A study of beaver in the Yaney region of Yellowstone National Park, Roosevelt-Wildl. Ann. 1, 1±191), increment cores collected from riparian aspen stands in 1998, and an extensive...
Aspen communities in the western U.S. are considered at risk because of low levels of disturbance and high levels of herbivory by wild and domestic ungulates. There appears to be a trend toward the loss of aspen-dominated stands West-wide. In some cases the loss is caused by succession, with shade-tolerant conifers becoming dominant. On dry sites where aspen is considered to be the climax, dete...
A spen (Populus tremuloides) provides important habitat for mammals and birds 1–3 , improves water retention in watersheds, 4 and has high aesthetic appeal in autumn. However, the amount and quality of aspen cover in the West has been declining for many years. For example, aspen cover in the Dixie and Fishlake National forests in Utah has decreased by more than 60% from historic levels, and in ...
Overview Quaking aspen is generally considered to be a fire-adapted species because it regenerates prolifically after fire, and it can be replaced by more shade-tolerant tree species in the absence of fire. As early-successional aspen stands transition to greater conifer-dominance, they become increasingly fire prone, until fire returns, and aspen again temporarily dominate. While this disturba...
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