نتایج جستجو برای: forest stands
تعداد نتایج: 123621 فیلتر نتایج به سال:
This study investigates the role of man-made disturbance on on nitrogen and phosphorus nutrient storage by herbaceous species in Gall Oak stands of Lorestan province. In order to do this study, two sites with the same physiographic and ecological conditions and different land uses were selected. Multiscale sampling plots were used randomly in each site to collect data on forest floor vegetation...
Forest management planning in Finland is currently adopting a new-generation forest inventory method, which is based on interpretation of airborne laser scanning data and digital aerial images. The inventory method is based on a systematic grid, where the grid elements serve as inventory units, for which the laser and aerial image data are extracted and the forest variables estimated. As an alt...
Large-scale Quercus variabilis natural secondary forests are protected under the Natural Forest Protection (NFP) program in China to improve the ecological environment. However, information about nutrient characteristics and carbon (C) storage is still lacking. Plant biomass and C, nitrogen (N) and phosphorus (P) stoichiometry of tree tissues, shrubs, herbs, litter, and soil were determined in ...
The object ive was to determine the ef fect iveness of a regular prescribed burning programfor reducing tree mortal i ty in southern pine forests burned by wi ldf ire . This s tudy was conducted on publ ic and industry lands in northeast Florida. On the Osceola National Forest, mean mortality was 3.5% in natural stands and 43% in plantations two growing seasons after u June 1998 wildfire. Burn ...
Acid rain results in losses of exchangeable base cations from soils, but the mechanism of base cation displacement from the forest floor is not clear, and has been hypothesized to involve mobilization of aluminum from the mineral soil. We attempted to test the hypothesis that losses of calcium from the forest floor were balanced by increases in Al in New Hampshire northern hardwoods. We measure...
Spatial variation in vegetation and coarse wood is a major source of forest heterogeneity, yet little is known about how this affects ecosystem processes. In 15-year-old postfire lodgepole pine (Pinus contorta var. latifolia Englem.) stands in Yellowstone National Park, Wyoming, we investigated how the decomposition rate varies with the position of coarse wood and other dominant structures with...
Hemlock woolly adelgid (HWA), Adelges tsugae Annand, a small aphid-like pest, is initiating rapid and widespread changes in composition and structure in southern New England hemlock forests. Rapid HWA expansion and extensive eastern hemlock (Tsuga canadensis) salvage logging threaten a region-wide reduction of this ecologically unique, culturally and economically important forest type. The purp...
Background and purpose: It is possible to monitor and study the natural growth and development of the forest ecosystems in the example of protected forest stands, which were excluded from management, and which are not under a negative influence of human activity. Therefore the aim of the research through the repeated measurements is to estimate the stand structure development on the Medveđak pe...
Leaf area index (LAI) is an important structural characteristic of forest ecosystems which has been shown to be strongly related to forest mass and energy cycles and forest productivity. LAI is more easily measured than forest productivity, and so a strong relationship between LAI and productivity would be a valuable tool in forest management. While a linear relationship has been observed betwe...
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