Abstract
According to the investigations results of afforestation in support of remote sensing(RS) and geographical information system(GIS), the study emphasized on how to make more suitable decisions in further afforestation engineering by using GIS technology in upstream regions of Yangtze Rivers, in the western Sichuan province in China. According to the survey results in different periods of remote sensing data (1999 and 2003) and field researches, it could be concluded as follows, 1 In order to get more public subsidy of afforestation, the local government registrated farmland areas were much more than actual afforested areas in practice. In our research region, on average only 25.4% (the relative bias of estimation is -15.4%) farmland areas had been afforested actually, however, the data reported by local government was 57.56% 2 the most serious problems in afforestation are: planting of a few pure tree species in the whole region and neglecting the adaptability of variation ecotype to local environmental conditions. It was supposed in the paper that afforestation was a systematic, long-time and complicated process which should be performed step by step. It was not only a spatial decision, but also a temporal decision in which the elements such as terrain, ecology, soil fertility, and forest species and so on, should be considered. And the time sequence of returning gain the plots to forestry should be carried out to decide where should be afforested firstly and where secondly.