Research On Rainfall Redistribution Function Of Mixed Broadleaf-conifer Forest In Jinyun Mountain In Chongqing

Taking the typical mixed broadleaf-conifer forest in Jinyun Mountain in Chongqing as the research object,this present thesis tries to explore their functions in rainfall redistribution.By using the methodologies of correlation analysis,regression analysis,principal component analysis and grey relational analysis,this thesis,taking the Pinus Massoniana and Gordonia Svchuanensvs mixed forest as an example,studies the rainfall redistribution functions of mixed broadleaf-conifer forests from a quantitative perspective,aiming at providing theoretical foundations for the management of water conservation forests.The major conclusions are as follows:The mixed broadleaf-conifer forests,in which Pinus Massoniana Lamb is the dominant species, occupy 55.66%of the whole forests,and therefore,they are the most widely distributed.The analysis of the biodiversity characteristics of all the plant communities shows that the Pinus Massoniana and Gordonia Svchuanensvs mixed forest is the richest in biodiversity and the most stable in community among the 5 types of mixed broadleaf-conifer forests.The average annual precipitation in Jinyun Mountain from 2002 to 2007 was 1296.30mm.In any given year,the rainfall can be depicted as a normally distributed single-peak curve,with a peak from April to October,amounting to 82.5%of the whole year's total rainfall with June(16.26%) being the maximum.The amount of rainfall changes significantly from year to year,with its relative variation and variation coefficient being 13.0%and 0.17 respectively.In this thesis,a set of 140 rains with significant runoff effects were selected and they can be classified into 3 types,including 104 light rains,23 moderate rains and 12 rainstorms(including heavy rains,rainstorms and large rainstorms).The maximum water holding capacity of the canopy of mixed broadleaf-conifer forests in Jinyun Mountain is 9.16～30.84 t·hm^-2.The maximum litter interception is 83.38～285.67t·hm^-2,with 70.20～234.67t·hm^-2 in effect.The largest water retaining capacity of soil is 4217.71～6828.28t·hm^-2,and the non-capillary capacity is 489.19～2525.67t·hm^-2.The following are the statistics provided by this thesis to illustrate the index of typical Pinus Massoniana and Gordonia Svchuanensvs mixed forest under the conditions of light rains,moderate rains and rainstorms respectively:canopy interception capacity being 28%,24%and 15%,litter interceptions being 11%,6%and 2%,overland runoff being 6%,9%and 15%,soil interceptions being 35%,31%and 22%and underground runoff being 20%,30%and 46%.In total,the forest interception capacities in different rainfall conditions are 74%,61%and 43%.