天童亚热带常绿阔叶林降雨再分配的数量特征

Rainfall redistribution in subtropical evergreen broad leaved forest in Tiantong

为了揭示我国东部沿海常绿阔叶林降雨再分配的生态学机制,2007年6月—2008年6月间在浙江天童森林生态系统国家野外科学观测研究站进行了定位研究。结果表明:研究期间,林外总降雨量1348.8mm,林内穿透雨量、树干茎流量和林冠截留量分别占总降雨量的81.7%、2.3%和16.0%;穿透雨量和树干径流量与降雨量均呈极显著的线性关系(P<0.01,n=122),穿透雨率和树干茎流率与降雨量的关系可用非线性曲线表示,当林外降雨量大于2mm时,林内才开始出现穿透雨和树干径流,当降雨量小于20mm时,树干径流率随林外降雨量的增加急剧增大,当降雨量大于20mm时,树干径流率的增加趋势逐渐变缓,趋于稳定;穿透雨量与冠层叶面积指数、树冠开放度以及降雨因子具有极显著相关关系(P<0.01,n=122),树干径流量随树干胸径的增大而增加;林冠截留率与降雨量、降雨持续时间、降雨强度、降雨时间、空气相对湿度均呈极显著负相关(P<0.01,n=122),而与风速呈极显著正相关(P<0.01,n=122)。

In order to reveal the ecological mechanism of rainfall redistribution in evergreen broad leaved forest in Chinese eastern coastal areas,permanent plot study was carried out from the meteorological data from July 2007 to July 2008 in Forest Ecosystem Observation and Research station in Tiantong,Zhejiang province. Results showed that the total rainfall outside the forest was 1 348.8 mm,and the throughfall,stemflow,and canopy interception accounted for 81.7%,2.3% and 16.0% of the total rainfal1 respectively. The throughfall and stemflow had significant linear relationships with rainfall （P〈0.01,n=122）,and the relationship between throughfall ratio （or stemflow ratio） and rainfall could be described by a nonlinear curve. Throughfall and stemflow happened while the rainfall outside the forest was more than 2.0 mm. There existed a significant exponential relationship between thoughfall and LAI （or cannopy openness） （P〈0.01,n=122）. The canopy interception rate showed significantly negative correlation with the rainfall,rainfall duration,rainfall intensity,and relative humidity during rainfall （P〈0.01,n=122）,but positive correlation with wind velocity （P〈0.01,n=122）.