نتایج جستجو برای: forest floor
تعداد نتایج: 137489 فیلتر نتایج به سال:
We propose a novel methodology, forest floor, to visualize and interpret random forest (RF) models. RF is a popular and useful tool for non-linear multi-variate classification and regression, which yields a good trade-off between robustness (low variance) and adaptiveness (low bias). Direct interpretation of a RF model is difficult, as the explicit ensemble model of hundreds of deep trees is co...
Between 1945 and 1965, 1.82 million hectares, or about 17 percent of the total commercial forestland in Oregon, were treated with 2.02 million kg DDT. Detectable residues of this insecticide might be present in forest soils, even those which have never received a direct application of insecticide. Forest floor and mineral soil samples were collected along four east-west transects across the Coa...
The contribution of the understorey vegetation to the spectral reflectance from the top of a forest canopy was investigated by the use of a forest canopy reflectance model. Detailed field data, i.e. forest leaf area index (LAI), tree structural parameters like the height, diameter and crown length of the trees, and the composition, distribution and reflectance of the forest floor, was collected...
C2-C10 hydrocarbon emissions from a boreal wetland and forest floor H. Hellén, H. Hakola, K.-H. Pystynen, J. Rinne, and S. Haapanala Finnish Meteorological Institute, PL 503, 00 101 Helsinki, Finland University of Helsinki, Department of Physical Sciences, Helsinki, Finland Received: 29 September 2005 – Accepted: 13 October 2005 – Published: 23 November 2005 Correspondence to: H. Hellén (heidi....
The Lake Tahoe basin, located along the California and Nevada border between the Carson and Sierra Nevada mountain ranges, represents a complex forested ecosystem consisting of numerous sub-watersheds and tributaries that discharge directly to Lake Tahoe. This synthesis focuses on historical and current nutrient pools and the effects of biomass management in watersheds of the basin relative to ...
Soil nutrient concentrations decreased in an aggrading southern Appalachian forest over a 20-year period. Construction of nutrient budgets showed significant nutrient sequestration aboveground including increased forest floor mass. We hypothesized that the changes in forest floor mass resulted from decreased litter decomposition rates because of decreased litter quality. In 1992 and 1993, we re...
We characterized pit and mound (PM) topography resulting from catastrophic wind in the Coweeta Basin, and located 48 PMs a across a variety of forest types. Our measurements included pit length, width, and depth; and mound height, thickness, and width. Species of fallen trees were identified, and DBH (diameter at breast height, 1.37 m) was measured for biomass determination. We identified five ...
The winter roost-site selection of most North American foliage-roosting bats is relatively unknown. We examined winter roost-site selection of Seminole bats (Lasirrrus seminolus) in the Lower Coastal Plain of South Carolina during January 2004. Seminole bats used a variety of day-roost structures including the canopy of overstory hardwood trees, hanging vines, pine needle clusters suspended fro...
Forests in Fukushima and neighboring prefectures accumulated atmospheric fallout of radioactive materials after the Fukushima Daiichi Nuclear Power Plant accident. We investigated the initial behavior of Cs deposited in coniferous forest plantations. Furthermore, we conducted in-situ measurements of radioactivity in coniferous and broadleaf forest canopies. The results of this study demonstrate...
Deforestation in the northern highlands of Ethiopia has left 35,000 forest fragments ranging in size from 3 to 300 ha (Bongers et al 2006). Deforestation produces edges which increase disturbance within the forest such as decreased water availability and increased light. To determine the degree of these edge effects and the nutrient status of these forests, I analyzed the nutrient composition o...
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