鼎湖山针阔叶混交林生态系统水文效应研究

Hydrological Effects of Coniferous and Broadleaved Mixed Forest Ecosystem in Dinghushan

摘要:

对鼎湖山针阔叶混交林水文效应的研究表明2002年8月-2003年7月,大气总降水量为1690 mm,林内净降水量为1212.7 mm,占总降水量的72%,其中穿透雨量和茎流量分别为1125.3和87.4 mm,占总降水量的66.6%和5.2%。林冠截留量为477.3 mm,截留率28.2%。地表径流量62.1 mm,占总降水量的3.7%。在一定的降水量范围内,林冠对降水的截留量随着降水量的增加而增加,不同的雨量级,林冠截留量变化的趋势曲线不同,且一次截留降水量饱和值约为25 mm;穿透雨量、茎流量均随着林外大气降水量的增加呈线性增加;当日大气降水量在0-30 mm时,地表径流量很小,且呈线性递增;当日大气降水量>30 mm时,地表径流量随降水量增加以对数递增。与马尾松纯林和季风常绿阔叶林相比,针阔叶混交林在减少地表径流和保持水土等方面具有更好的水文生态效应。

Abstract:

Hydrological effects of coniferous and broadleaved mixed forest ecosystem in Dinghushan were studied from August 2002 to July 2003. The total precipitation during this period was 1 690 mm, of which the net precipitation under canopy was 1 212.7 mm, accounting for 72% of the total. The amounts of throughfall and stemflow were 1 125.3 mm and 87.4 mm, respectively, accounting for 66.6% and 5.2% of the total precipitation, respectively. Canopy interception was 447.3 mm, with an interception rate of 28.2%. The surface runoff was 621 mm (about 3.7％ oftotal precipitation)．It was shown that the amount of canopy interception increased with the increasing of precipitation，but having various tendency for different precipitation intensity classes． However, the critical canopy interception for precipitation event was about 25 mm． Throughfall and stemflow were linearly related to the precipitation．The surface runoff was also linearly related to precipitation when the daily precipitation was ≤ 30 mm， but nonlinearly related to precipitation at >30 mm． Compared with monsoon evergreen broadleaved forest or pure coniferOLlS forest，the coniferous an d broadleaved mixed forest had a greater hydro-ecological effect on decreasing surface runofr and water and soil conservation.