نتایج جستجو برای: forest soils
تعداد نتایج: 150689 فیلتر نتایج به سال:
Acidic deposition leads to the acidification of waters and accelerated leaching and depletion of soil base cations. The Bear Brook Watershed in Maine has used whole-watershed chemical manipulations to study the effects of elevated N and S on forest ecosystem function on a decadal time scale. The objectives of this study were to define the chemical and physical characteristics of soils in both t...
Abstract. More than 100 site years of hydrology and water quality data spanning 25 years (1976-2000) were compiled from research and monitoring studies on forest stands with natural vegetation and tracts managed for timber production. A total of 41 watersheds located on poorly drained to very poorly drained soils on flat divides between coastal streams were included ranging in area from 7.3 to ...
—We investigated the relationships of vegetation communities to environmental variables and compared the relative contribution of native and introduced species in extant forest communities on St. John, US Virgin Islands, using an island-wide forest vegetation inventory and monitoring network of permanent plots. We detected 2,415 individuals of 203 species, 5 percent of which were introduced. Cl...
[1] The character and quantity of dissolved organic carbon (DOC) were studied in nine small boreal streams and adjacent soils during two years, with focus on the spring snowmelt period. The streams cover a forest-wetland gradient, spanning from 0% to 69% wetland coverage. Lower values of the absorbance ratio measured at 254 nm and 365 nm (A254/A365), in both soil plots and streams, indicated th...
The 4-nitrophenyl phosphate method for acid phosphomonoesterase (EC 3.1.3.2; acid orthophosphoric monoester phosphohydrolase) determination was slightly modified to increase the sensitivity and the stability of the 4-nitrophenol coloured complex in samples rich in humic substances and easily soluble organic compounds. Based on an approach used for mycorrhizal roots, the new analytical protocol ...
Airborne Light Detection and Ranging (LiDAR) is a survey tool with many applications in forestry and forest research. It can capture the 3D structure of vegetation and topography quickly and accurately over thousands of hectares of forest. However, very few studies have assessed how accurately LiDAR can measure surface topography under forest canopies, which may be important, for example, in re...
Forest fires are important contributors of C, N, and Hg to the atmosphere. In the fall of 2011, a large wildfire occurred in northern Minnesota and we were able to quickly access the area to sample the forest floor and mineral soil for C, N, and Hg pools. When compared with unburned reference soils, the mean loss of C resulting from fire in the forest floor and the upper 20 cm of mineral soil w...
It is widely recognized that global warming promotes soil organic carbon (SOC) decomposition, and soils thus emit more CO2 into the atmosphere because of the warming; however, the response of SOC decomposition to this warming in different soil textures is unclear. This lack of knowledge limits our projection of SOC turnover and CO2 emission from soils after future warming. To investigate the CO...
0022-1694/$ see front matter Published by Elsevier doi:10.1016/j.jhydrol.2009.12.041 * Corresponding author. Present address: Ecosys Environmental Protection Agency, 960 College Station United States. Tel.: +1 706 355 8338; fax: +1 706 355 E-mail addresses: [email protected] (K. Price (C.R. Jackson), [email protected] (A.J. Parker). A full understanding of hydrologic response to human impact r...
Understanding forest carbon cycling responses to atmospheric N deposition is critical to evaluating ecosystem N dynamics. The natural abundance of N (dN) has been suggested as an efficient and non-invasive tool to monitor N pools and fluxes. In this study, three successional forests in southern China were treated with four levels of N addition. In each treatment, we measured rates of soil N min...
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