Water Retention Capacity Evaluation of Main Forest Vegetation Types in the Upper Yangtze Basin
长江上游地区主要森林植被类型蓄水能力的初步研究

The upper Yangtze basin,with abundant forest resources, is an important water sources area,which functions as water tower for the territory of eastern China.Evaluation of water retention capacity of forest ecosystems can provide important references for ecosystem function assessment and ecological construction.We collected data of water retention information of forest canopy,litter and soil function layers to evaluate rainfall interception and comprehensive capacity of water retention by 14 forest vegetation types according to mountain climate zones and growth form classification of forest.Among comprehensive water retention capacity,water retentions in soil and litter layer account for the most proportion.Soil non-capillary porosity plays the key role in the determination of water retention capacity of ecosystem.The water retention capacity of litter and whole ecosystem can be evaluated by phytomass of litter and soil non-capillary por-osity.Subtropical evergreen broad-leaved forest,evergreen and deciduous mixed broad-leaved fore-st,hemlock,maple and birch mixed forest,spruce and fir forest and sclcrophyllous evergreen broad-leaved forest have more water retention capacities among the forest ecosystems in the upper Yangtze River and have wide distribution in the high mountain and dissected gorge area. These ecosystems are important for water retention and soil conservation throughout the basin. Therefore,it is of great significance to implement ecological engineering programs such as natural forest protection and convertsion of farmland to forest in the upper Yangtze basin.