tailieunhanh - Báo cáo "Defining required forest area for protection soil from erosion in Vietnam: a GIS-based application "

Forests play an important role in reducing erosion. In Vietnam, destroying natural forests in mountainous areas has caused serious environmental problems for sustainable development. Required forest areas for protection of soils from erosion in Vietnam are defined in this study. An algorithm of defining required forest area for soil erosion prevention is based on a comparison of soil loss prediction and its threshold of 10 ton ha-1yr-1 (soil loss tolerance) within the GIS environment. Soil loss is predicted from rainfall erosivity index, slope, porosity and. | VNU Journal of Science Earth Sciences 27 2011 63-76 Defining required forest area for protection soil from erosion in Vietnam a GIS-based application Tran Quang Bao1 Melinda J. Laituri2 1 Vietnam Forestry University Xuan Mai Chuong My Ha Noi Vietnam 2Warner College of Natural Resources Colorado State University Fort Collins CO 80523 USA Received 15 March 2011 received in revised form 19 April 2011 Abstract. Forests play an important role in reducing erosion. In Vietnam destroying natural forests in mountainous areas has caused serious environmental problems for sustainable development. Required forest areas for protection of soils from erosion in Vietnam are defined in this study. An algorithm of defining required forest area for soil erosion prevention is based on a comparison of soil loss prediction and its threshold of 10 ton ha-1yr-1 soil loss tolerance within the GIS environment. Soil loss is predicted from rainfall erosivity index slope porosity and vegetation structures in which rainfall index is calculated from 30 year monthly rainfall data of 158 weather stations. A map of erosion risk for Vietnam illustrating potential to erode soil was generated from slope rainfall index and soil porosity by using spatial interpolation and map algebra techniques in ArcGIS. Vegetation index a function of canopy closure height ground cover and litter cover is classified into four groups. Required forest areas for protection of soil from erosion are defined from an erosion risk map in comparison with categories of vegetation index. An area a raster cell requires forest natural forest or the others when its erosion risk is higher than the vegetation index. Keywords Soil Erosion GIS Required Forest Area Erosion Risk Map Soil Loss. 1. Introduction Soil erosion by water is one of the most serious environmental problems in the world. It causes adverse effects on soils agricultural production water quality Lal 2001 1 . Worldwide soil erosion rate are highest in Asia Africa and .