Community Characteristics of Shrub Vegetation by Forest Closing in Dagou Catchment,Upper Reaches of Minjiang River

In order to understand the effect of closed forest, the species composition,flora characteristics,height class structure,diameter class structure and species diversity were analyzed in a 1 hm2plot in natural recovery shrub stage of forest vegetation in Dagou catchement,upper reaches of Minjiang River.There was a floristic composition with 43 families,88 genera,and 135 species in the plot,in which,there were 49 species of 44 genera of 21 families of herbs and 86 species of 47 genera of 34 families of woody plants(trees and shrubs combined).The areal-types of families and genera were abundant,but the areal-types of families dominated by North Temperate and Cosmpolitan component,which accounted for 34.9%,respectively.The areal-types of genera were dominated by temperate genera,accounting for 72.8%,in which north temperate genera was 39.8%.Both the species number and individual density decreased with the increasing of height class and basal diameter.There was a significant positive correlation between species abundance and individual density for different height class and different basal diameter in the community.Although the physiognomy of the community was shrubby,the component was rich.The tree species in climax community of the region(such as Quercus liaotungensis) was present and somewhat dominant in the community.Closed forest was an effective method to restore the degraded community caused by human disturbance in the valley.