为了评估青海云杉林的水源涵养服务功能,选择祁连山西水林区排露沟流域青海云杉林,定位监测了在2006年中共83次降水事件的截留分配效应,观测期降水总量为394.2 mm,林冠截留、茎流和穿透水量分别是139.1、1.96和253.1 mm,林冠截留率、茎流率、穿透率分别为35.28%、0.50%和64.22%,当林外降水量〉0.8 mm时才观测到林内穿透雨,而大于13.60 mm时,才观测到树干茎流。林冠对降水的截留分配与降水量、降水形态以及林分特征密切相关。冠层截留量、茎流量和穿透量与降水量均呈正相关,冠层截留率与降水量呈负相关,而茎流率和穿透率呈正相关;林冠对降雪的截留强于降雨,而降雨的穿透量强于降雪,同一降水事件下树干茎流量随着胸径的增大而增加。青海云杉林冠的几何形态结构(枝叶的分布与排列)不利于形成树干茎流。
To evaluate water conservation function of Picea Crassifolia forest in the Xishui of Qilian Mountains,interception distribution effect of 83 precipitation cases were monitored in 2006.The total precipitation is 394.2 mm,canopy interception,stem-flow,throughfall are 139.1 mm,1.96 mm,253.1 mm,which account for 35.28%,0.50%,64.22% respectively.When precipitation over 0.8 mm and 13.6 mm,throughfall and stem-flow could be recorded respectively.Canopy interception and redistribution are closely related with precipitation,precipitation situation and forest stand characteristics.The canopy interception,stem-flow and throughfall are positively correlated with precipitation amount,but canopy interception rate was negatively related with precipitation,stem-flow rate and throughfall rate are positively correlated with precipitation.The capability of canopy interception snow is much higher than rainfall interception,rain throughfall is higher than snow.The stem-flow increases with the increase of tree diameter.The stem-flow does not happen easily since the.canopy shape structure of Picea Crassifolia forest.