几种常用造林树种冠层对降水动能分配及其生态效应分析  

DISTRIBUTION OF RAINFALL KINETIC ENERGY BY CANOPIES OF ARTIFICIAL FOREST TREE SPECIES,AND ITS ECOLOGICAL EFFECTS

作　　者：周国逸[1] 

机构地区：[1]中国科学院华南植物研究所

出　　处：《植物生态学报》1997年第3期250-259,共10页Chinese Journal of Plant Ecology

基　　金：中国科学院院长基金

摘　　要：本文从理论上系统地论述了林冠如何调节到达林地的降水动能，推导了计算大气降水和穿透水动能的理论和方法。经由理论推导指出并非所有的森林都适合作为水土保持林，即由穿透水的水滴直径较大，而且不受大气降水强度的影响及穿透水常常不是以最大的稳定速度到达林地这两个规律来讨论森林冠层在水土保持功效方面所具有的地位，可以做为营造水土保持林的理论基础。This research developed a systematic method of calculating waterdrop kinetic energy of rainfall and throughfall and explained how a forest canopy redistributes the rainfall kinetic energy and controls the throughfall kinetic energy.It was thus proposed that not all forests are suitable to functioning as water and soil conservation.For atmospheric precipitation,the number of raindrops distributes in a normal distribution,i.e.N(a,b), where,a is the average diameter of raindrops and b is the standard deviation.My research shows that there was the following relations among a,b and the precipitation intensity (P) that determines a and b,a=132665+0319051nP (r>0998);b=075551+000223P(r>0995)However,for thoughfall,the a and b are not determined by P but by the structure of canopy.For a definite canopy,a and b are definite.This is shown below for canopies of some tree species:Cunninghamia lanceolata:N(37,098);Pinus massoniana:N(35,097);Sassafras tzumu:N(41114):Eucalyptus exserta;N(39,109);Acacia mangium:N(38,106).For most canopies,the diameter of throughfall(in fact,it is not all throughfall but just dribbling waterdrop from leaves of canopy) is larger than the diameter of atmospheric precipitation raindrop,which will increase the dash of waterdrops to the forest land,especially in the situation of low intensity of rainfall.Therefore,in general,the forest canopy will hamper the topsoil conservation on forest land.However,forests often have underlayer vegetation which,unlike the forest canopy,actually plays an important part in soil conservation.The main function of forest in aspect of water and soil conservation is to protect the deep soil from landslide with its complex root system.When making water and soil conservation forest,we should consider a number of factors,such as precipitation characteristics in that region,the density of trees,the height of fores

关 键 词：森林生态学 林冠 降水动能 生态效应 

分 类 号：S718.512.3[农业科学—林学]