نتایج جستجو برای: pinus ponderosa
تعداد نتایج: 13623 فیلتر نتایج به سال:
The chemical composition of the essential oils from the needles of Pinus ponderosa (north american pine), P. resinosa (red pine) and P. strobus (eastern white pine) has been determined by GC/MS (FID). The essential oils from P. resinosa and P. ponderosa in comparison to P. strobus have been characterized by the higher content of beta-pinene (42.4%, 45.7% and 7.9% respectively). On the other han...
1. The acidification effect of Ponderosa pine (Pinus ponderosa) needles on soil pH was tested by sampling and measuring pH of soil in areas with ponderosa pine needle litter and without. 2. A total of three depth classes for five samples in each category of pine needles present and absent were collected and analyzed. 3. Statistical analysis of pH data did not indicate statistically significant ...
Recent increases in Pinus ponderosa Dougl. ex Laws. forest density in the southwestern United States have severely reduced understory herbaceous biomass and altered understory species composition. To examine whether changes in graminoid species composition are caused by increased shading, we studied the effects of shade on leaf gas exchange, biomass, and reproductive characteristics of five gra...
—In northern areas of their expanded range, information on Merriam’s turkeys (Meleagris gallopavo merriami) is lacking, specifically pertaining to wintering behavior and factors associated with winter habitat selection. Forest managers need detailed quantification of the effects of logging and other management practices on wintering habitats needed by Wild Turkeys and other wildlife. Therefore,...
Biomass combustion is a major biogeochemical process, but uncertain in magnitude. We examined multiple levels of organization (twigs, branches, trees, stands, and landscapes) large, severe forest fires to see how rates for live aboveground woody parts varied with tree species, size, fire severity Ponderosa pine (Pinus ponderosa Dougl. ex Laws.) mixed conifer-dominated forests the Sierra Nevada,...
Pinus ponderosa Laws. (ponderosa pine) forests have changed considerably during the past century, partly because recurrent fires have been absent for a century or more. A number of studies have explored the influence of timber harvest or burning on understory production in ponderosa pine forests, but study designs incorporating cutting and prescribed burning in an experimental framework are nee...
Population variation in ecophysiological traits of four co-occurring montane conifers was measured on a large latitudinal gradient to quantitatively assess their potential for response to environmental change. White fir (Abies concolor) had the highest variability, gross photosynthetic rate (Pg), and foliar carbon (C) and nitrogen (N) content. Despite low water use efficiency (WUE), stomatal co...
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