辽宁东部山区几种主要森林植被类型林冠层对降雨的再分配作用

Canopy Rainfall Redistribution for Various Major Forest Vegetation Types in Eastern Liaoning Mountainous Region

用固定标准地方法对辽东山区5种主要森林植被类型生长季林冠的降雨再分配特点进行了研究。结果表明,生长季时期降雨林冠再分配特点因林型而异。林冠截留率23.1％～29.3％,平均值为25.3％,针叶林的截留率大于阔叶林。辽东山区林内雨率68.9％～76.3％,平均值为73.4％,阔叶林大于针叶林。各林型的茎流率都很低,不超过1％;5种林型生长季场降雨的截留量都表现出随降雨量的增大而增大。截留率随降雨量的增大而减少,在降雨初期下降梯度最大,以后趋于平稳,达到饱和,各林型的理论饱和截留率为16.4％～29.7％。林内雨量在低雨量级时增加缓慢,随降雨量增大,增加梯度明显加大。林内雨率在低雨量时增加梯度大,而到高雨量级时,逐渐趋于稳定。从平均角度看,阔叶林的林内雨率要高于针叶林。茎流量在降雨超过一定量时发生,在低雨量级时增加缓慢,以后随雨量级增大而大致呈直线上升,茎流率不超过1％,茎流量不超过0.2 mm。

The rainfall redistrbution characteristics of canopy during growth period for five major forest vege-tations in Eastern Liaoning mountainous regions were studied using fixed standard sample method . Theconclusions drawn in this paper were as follows. The rainfall redistributions of canopy during growth periodwere different with forest vegetation types. The relative canopy interception ranged from 23. 1% to29.3%, averaged 25.3%, being larger for conifers than for hardwoods. The relative throughfall in this re-gion ranged 68. 9 % ~ 76. 3 % , averaged 73.4%, showing larger for hardwoods than for conifers. All theseforest vegetations behaved lower relative stemflow, less than 1 % . The rainfall redistribution behaviors inevent rainfalls during growth period for these forests were characterized as follows. The interceptions in-creased with precipitation, and contrarily the relative interception decreased with it, dropping down quicklyduring initial rainfall period and then slowly and finally reaching the canopy-saturated state. The saturatedrelative interception was estimated 16.4% ~29.7% by fit models. As for throughfall, it rose slowly at thelower level of rainfall, and then went up with it apparently quickly . The relative throughfall increasedsharply at the lower rainfall level, then tending a stable state. On the average, relative throughfall for hard-woods was larger than for conifers. Stemflow just occurred as the rainfall exceeded a certain level, and atthe lower level of rainfall it increased slowly, then going up linearly with the rainfall getting larger. Gener-ally, the relative stemflow was less then 1 % , stemflow less than 0.2 mm.