Comparison of Community Types and Species Diversity of Evergreen Broad-leaved Forests(Tree layer) of Daguping Forest Farm

An investigation was conducted over the change of species diversity in the tree layer of evergreen broad-leaved forests along the altitude gradient at different terrains(hillside and valley) of Daguping Forest Farm,Shuangpai County,Hunan Province.67 arboreal plants belonging to 35 families,55 genuses,were observed.The species diversity in the valley is higher than that in the hillside.This indicates that the species diversity will be increased by mid-degree human disturbance.The increase of species diversity in the tree layer of evergreen broad-leaved forests along the high-altitude gradient indicates that the species of tree layer keep relatively stable in the specified stage of community succession.