نتایج جستجو برای: forest watershed
تعداد نتایج: 121015 فیلتر نتایج به سال:
The Water Erosion Prediction Project (WEPP) model is a physically-based soil erosion tool developed to predict runoff and erosion. Databases for forest soil, vegetation, and climate conditions have been developed. Background sediment may be generated annually from undisturbed forests, and occasionally following wildfire. In some cases, it may be appropriate to include sediment from essential fo...
With increasing energy costs, society is looking at alternative energy sources. One potential energy source that is currently underused in the United States is forest biomass (Rummer et al. 2003). However, if forests are subject to a significant increase in biomass removal for energy production, then it is possible that hydrologic resources may be adversely affected. This report describes fores...
Institutional mapping is a technique that builds on the logic of Geographic Information Systems (GIS). In GIS, coverages placed over a base map show spatial relations. Social institutions are more difficult to ‘‘map’’ physically. Institutional mapping uses three social coverages—scale, power, and capital. Four sets of institutions affecting watershed management—salmon restoration, water quality...
Watershed segmentation of spectral images is typically achieved by first transforming the high-dimensional input data into a scalar boundary indicator map which is used to derive the watersheds. We propose to combine a Random Forest classifier with the watershed transform and introduce three novel methods to obtain scalar boundary indicator maps from class probability maps. We further introduce...
Sulfur inputs to forest ecosystems originate from mineral weathering, atmospheric deposition, and organic matter decomposition. In the soil, sulfur occurs in organic and inorganic forms and is cycled within and between those forms via mobilization, immobilization, mineralization, oxidation, and reduction processes. Organic sulfur compounds are largely immobile. Inorganic sulfur compounds are mo...
Maintenance of a sustainable clean water supply is critical for our future. However, watershed degradation is a common phenomenon around the world that leads to poor water quality. In order to protect water resources, the Watershed Forest Management Information System (WFMIS), was developed as an extension of ArcGIS and is described in this paper. There are three submodels to address nonpoint s...
Changes in surface soil C and N can resuh from forest management practices and may provide an index of impacts on long-term site productivity. Soil C and N were measured over time for five watersheds in the southern Appalachians: two aggrading hardwood forests, one southand one north-facing, undisturbed since the 1920s; a white pine (Pinus strobus L.) plantation planted in 1956; and two regener...
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...
Air pollution and watershed research in the central Sierra Nevada of California: nitrogen and ozone.
Maintaining healthy forests is the major objective for the Forest Service scientists and managers working for the U.S. Department of Agriculture. Air pollution, specifically ozone (O3) and nitrogenous (N) air pollutants, may severely affect the health of forest ecosystems in the western U.S. Thus, the monitoring of air pollution concentration and deposition levels, as well as studies focused on...
The Bear Brook Watershed in Maine (BBWM), USA, and the Fernow Experimental Forest in West Virginia, USA, represent unique, long-term, paired, whole watershed, experimental manipulations focusing on the effects of nitrogen (N) and sulfur (S) deposition on temperate forests. Both watersheds began whole-ecosystem additions of N and S as (NH(4))(2)SO(4) in the fall of 1989, and both are entering th...
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