辽河源3种林分降雨再分配特征及其影响因素

Traits and Influencing Factors of Rainfall Redistribution in Three Types of Forest in Liaoheyuan

于2013和2014年5—9月对辽河源自然保护区油松林、山杨林和华北落叶松林的穿透雨、树干茎流和林冠截留进行了监测,分析森林冠层对降水再分配的影响。结果表明:(1)油松林、华北落叶松林和山杨林的穿透雨率分别为78.8%,81.1%和83.8%,3种林分穿透雨量与林外降雨量呈线性正相关,穿透雨月变化与林外降雨量月变化趋势一致,油松林、山杨林和华北落叶松林产生穿透雨的临界降雨量分别为1.5,0.9,1.2mm;3种林分的树干茎流率分别为油松林0.8%、华北落叶松林1.0%、山杨林3.7%,树干茎流量与降雨量成正比。(2)林冠截留能力为油松林(20.4%)>华北落叶松(17.9%)>山杨林(12.4%),油松林的林冠截流率显著高于山杨林,在降雨量较小时表现更加明显,降雨特征和冠层结构对林冠截流都产生影响。

Throughfall,stem flow and canopy interception of three types of forest（Pinus tabulaeformis forest,Larix principis-rupprechtii forest and Populus davidiana forest）were studied in Liaoheyuan Natural Reserve,Hebei province,through a field investigation from May to September in 2013 and 2014.The results showed that：（1）Throughfall rates of P.tabulaeformis forest,L.principis-rupprechtii forest and P.davidiana forest were 78.8%,81.1% and 83.8%,respectively.Throughfall amounts of three forests all showed positive linear correlation with rainfall amounts outside the forests.The monthly variations of throughfall were consistent with the monthly trend of rainfall outside the forest.Throughfall happened when rainfall exceeded 1.5 mm for P.tabulaeformis forest,0.9 mm for P.davidianaforest and1.2 mm for L.principis-rupprechtii forest.Stem flow rates in the three types of forests were 0.8%,1.0%and 3.7%,respectively,and the regression analysis showed that stem flow amounts of the three forests had positive linear relationship with rainfall amount.（2）The capacity of canopy interception ranked from higher to lower as P.tabulaeformis forest（20.4%）〉L.principis-rupprechtii forest（17.9%）〉P.davidiana forest（12.4%）.The canopy interception of P.tabulaeformis forest was significantly greater than that of the P.davidianaforest,which was more obvious under small rainfall events,and the rainfall characteristics and canopy structure had an influence on the canopy interception.