The geographical information system was the science and technology of managing and analysing the space data,introducing 3S technologies to the forestry department of our country.With technologies of RS and GPS,the county-level forestry management information system was established based on GIS,which was inevitable requirement of forestry management.Therefore,the authors founded the forestry management information system of Shimian County,based on investigation on the spot and collecting materials,and regarded setting up the road's foundation geographical information system of the foundation of Shimian County,the application of the geographical information system of the foundation,etc.It offered reference for the database construction of the forestry management information system in the future.

Because high-resolution satellite image has heavy amount of information, increasing detail, complicated texture change and so on, its interpretation faces new difficult problem. Analyzing various kinds of surface feature characteristic information of QuickBird satellite image, this text makes use of remote sensing and geographical information system to interpret types of land use of Juntun Township of Xindu District of Chengdu City in Sichuan Province and sets up corresponding Juntun from 1:2 000 to 1:50 000 scale spatial database. Its achievement will offer the important reference basis for Juntun land use /cover change and offer a little experience for other plain area.

Here we report the dynamic change of forestland in the late 1990's in Sichuan Province.With the technologies of remote sensing and/or GIS,we obtained the land-use digital data of 1995 and 2000,the soil erosion data of 1995 and the data of slope grade,environment quality grade,geomorphic region,and administration districts.All of these data were further sampled into the raster data with a resolution of 100 meters and projected into the same coordination system with the same resolution.After extraction,overlay and statistical analyses,we characterized the dynamic forestland change in the late 1990's.Our data indicate that the net increase of forestland was mainly resulted from the transformation of grassland and other land types;while most of the net decrease of forestland was attributed to cultivation,construction and residential land-uses.The net reduced forestland that totally amounts to 7972 hectares occurred in the regions with slight soil erosion,higher slope grade and mild environment quality,which were mainly located in the cities of Guangyuan,Mianyang and Dazhou,as well as other mountainous regions around the Sichuan basin.In contrast,the net increased forestland was mainly distributed in the regions with considerable to moderate soil erosion and the regions with lower slope grade and better environmental quality.Although partially improved,the general ecological function of the forestland was deleterious since the effect of the project of converting cultivated land into forestland was not functionally obvious until the late 1990's.Based on our result,we suggest that the forest protection should be further reinforced in the northwestern plateau and southwestern mountainous regions of Sichuan province,especially the regions with higher slope and unstable ecological environment,which include Ganzi Tibetan Autonomous prefecture,Leshan city,Yaan city and Aba Jiang &Tibetan Autonomous prefecture.