基于月水量平衡的天山中部天然云杉林森林生态系统蓄水功能研究

Study on Water Resource Conservation of Natural Spruce Forest Ecosystem Based on Month Water Balance in the Middle Tiansh Mountains

以天山中部天然云杉林森林生态系统为研究对象,以250 hm2流域尺度为单元,采用流域试验和水量平衡样地相结合的方法,对森林生态系统的月水文过程进行全面、系统地研究。结果表明:(1)在降雨分配过程中,80.39%的雨量分配是在土壤层完成的;其次,林冠截留率较大,占降雨量的17.92%,并且随着林龄的增大,单位面积产生的截留越强;单位面积产生径流量最小,仅为降雨量的2.75%,其中,单位面积裸地的产流最大,分别为草地和林地的5.4,12.5倍。(2)蒸发散是流域森林生态系统的最大损耗方式,占月总水分输入量的69.53%;而以径流方式产生的水分流失最小,仅占降雨输入量的3.8%;剩余26.67%的水分则以水源涵养的方式贮蓄在土壤中。(3)降雨在森林生态系统各层次的分配规律为:树木蒸腾>土壤蓄水>林冠截留>土壤蒸发>地表径流>地下径流,分别占水分总输入量的43.93%,26.67%,17.92%,7.68%,2.75%和1.05%。

Taking the 250 hm2 natural spruce forest ecosystem in the middle Tianshan mountains as study object,with the method of combining watershed test and water balance,the water quantity were analyzed synthetically to determine the effects of different ecosystem components.The results showed that：（1）The 80.39% of the rainfall distribution was completed in the soil layer during the water transformation process;The canopy interception rate was 17.92% of the rainfall.And the influence of forest interception on water quantity of rainfall was enhanced as the forest age increased.The surface runoff only holds up 2.75% of rainfall.The surface runoff amount produced by bare ground was 5.4 times of grassland and 12.5 times of forest ground.（2）The evapotranspiration held 69.53% of the water loss amount of forest ecosystems was the maximum loss measure.The water loss of runoff was only 3.8% of rainfall input;26.67% rainfall was conserved in the soil as net water income of forest ecosystem.（3）The orderliness of rainfall distribution different levels in forest was：Trees transpiration〉soil water storage〉canopy interception〉soil evapotranspiration〉surface runoff〉underground runoff,the percents hold the rainfall one by one was：43.93%,26.67%,17.92%,7.68%,2.75% and 1.05%.