大兴安岭南段白桦林降雨再分配特征研究

Rainfall redistribution in natural Betula platyphylla forests in south of Da Xing'an Mountains

利用2013年度赛罕乌拉地区白桦林64场有效降雨及林内再分配的野外观测数据,探讨了该地区白桦林降雨再分配特征。结果表明:白桦林的穿透降雨量、树干茎流量和林冠截留量分别占同期林外降雨量的76.0%,2.3%,21.7%。穿透降雨量及树干茎流量与林外降雨量均呈明显的线性相关(R2=0.8800),而林冠截留量与林外降雨量呈指数函数关系(R2=0.8303)。实验证明当林外降雨量大于0.3mm时,可发生穿透降雨;林外降雨量大于0.51mm时,可发生树干茎流。林冠层叶面积指数(LAI值)及独特的立地条件、生长特征对降雨再分配起着重要的影响。

Using the field observation data of 64 rainfalls, throughfall and stemflow, we researched characteris- tics of rainfall redistribution and the effect of the canopy interception on the natural Betula platyphylla forests in the research site. The results showed that： throughfall, stemflow, and canopy interception accounted for 76. 0% , 2.3% and 21.7% of rainfall outside the forest in the same period, respectively. The throughfall amounts and stemflow had statistically significant linear relationships with rainfall outside the forest. The canopy intercep- tion and rainfall outside the forest was an exponential function relation. According to the regression equation, throughfall occurred when the rainfall was greater than 0.3ram and stemflow occurred when the rainfall was grea- ter than 0. 51 mm. The leaf area index unique site conditions and growth festures of natural Betula platyphyUa for- ests played the very important roles in rainfall redistribution in the research site.