SPATIO TEMPORAL CHANGES OF LAND USE IN YUANYANG COUNTY

Based on Remote Sensing and GIS,this paper studies the land use change of yuanyang county during 1974 to 2000.The results are shown as follows:1)in three periods,forest land are main types of land use,which occupied 50% of total area of yuanyang,area of water-arable land and dry-arable land relatively is 15% and 20%,and other land use types only occupies 30% of total area,which showed land use structure changed little during 1974-2000.It also shows that at time scale within 30 years,the macrostructure of land use of a watershed doesn't change greatly;2)generally speaking,during 27 years between 1974 and 2000,the area of forest land,water-arable land,dry-arable land and unused land have been decreasing,Results also show that the area of woodland and garden land increased.3)During these periods,intertransitions between different types of land use are very complex,mainly occurring among woodland,waste grassland and water-arable land.The most notable transition occurred between dry-arable land to water-arable land,dry-arable land to waste grassland and so on;4)The main reasons of land use change in yuanyang are probably policies and economic development.