The analysis of the 3 stages＇ （1988,1996,2000） variation of land-cover is performed according to Thematic Mapper （TM） and Enhancement Thematic Mapper（ETM） satellite image by combining ground GIS database with GPS field collected data in the area of Xiaowan-Dachaoshan Reservoirs of Lancangjiang River cascaded Hydropower Area. Consequently, the land-cover is divided into five subclasses, namely water, paddy field and wetland, bare dryland and sparse shrub, secondary forest and density forest. The result showed that the areas of bare land, upland and secondary forest decreased in 1988-1996, whereas from 1996 to 2000, water body and density forest keep invariability while the areas of paddy field and wetland, bare dryland and sparse scrub increasing and the area of secondary forest decrease; Features of reciprocal transformation between density forest and other type of land-cover had two points, i.e. secondary forest, bare dryland and sparse shrub converted to density forest; and density forest converted to secondary forest and paddy field and wetland. It reflects the dynamic variation of density forest; the area which slope less than 8° and greater than 15° shows bigger variation, however, less change in 8°-15°.
LIU HongjiangXIE HongzhongCHEN LihuiGAN ShuZHANG JunWEI Fangqiang
