Decision on Reforesting and Regrassing Some of the Dry Sloping Cultivated with Support of GIS and Remote Sensing in Yunnan
遥感和GIS支持下的云南省退耕还林还草决策分析

The strategy to develop China's western region has been proposed by the central Governmant and ecological environmental construction constitute a very important part of the strategy. In order to improve the ecological environment of China's western region, a great deal of the dry upland must be reforested and regrassed. Where the dry upland must be changed into the forestland or grassland is quite essential GIS is identified as a useful tool to find the place where the dry upland must be changed into forestland or grassland in Yunnan province, Southwest China. Four steps are included. Firstly, relevant databases are established including land use database, elevation database, slope database, soil erosion database, water body database, precipitation database and temperature database. Secondly, the dry land from landuse database was overlain with slope database, soil erosion database, normalization vegetation index(NDVI) database. The distribution of the dry land of different slopes was analyzed. The distribution of the dry land of different slopes under different soil erosion conditions with different NDVIs is also analyzed. Thirdly, the expert knowledge about the upland cultivated was collected, and the model for finding the suitable place for being returned back to forestland or grassland is formulated on the basis of the knowledge. Finally, the suitable place is overlain with the precipitation layer and temperature layer to decide where trees need be planted and where grass need be planted. It shows that the results are very useful for the ecological environment construction in Yunnan Province.