Composition and distribution of vegetation after anthropological disturbance in the Huoxi River Region of Min Mountain,Sichuan Province

The data on topography maps,vegetation map of Pingwu County and our vegetation survey were used to make vegetation map and DEM of the studied area.By classifying vegetation and analyzing vegetation map and DEM,the pattern of composition and distribution of vegetation along altitude,slope degree and slope aspect gradients were studied.The results show that:(1)Human disturbance especially timbering has resulted in the disappearing of coniferous and broad-leaved mixed forests in the area.And the area of coniferous forests has shrunk while the area of broad-leaved forests and shrubs has increased;(2)Vegetation distribution shows conspicuous altitudinal gradient.Except for farmlands,the area proportions of other vegetation types are similar with that of the working sites at various position of slope.Distribution of coniferous forests,broad-leaved forests,farmlands and shrubs are influenced by slope aspect;(3)It seems that vegetation types and proportions of their areas in the studied area have been changed by human disturbance,which can be seen along the altitude gradient.