Study On Modeling Of Competition Indices Of Pinus Tabulaeformis Individual Treesat Badaling Area

In this research, Pinus tabulaeformis at Badaling national forest park was the research’s object, purpose is gain the best individual competition model of Pinus tabulaeformis. It has realistic means in individual tree modeling research,growth and yield study、undergrowth study,thinning phenomenon、 simulate various kinds of tending and select cutting etc.This study important to badaling pinus forest’s space structure study, and important to perfect the ecosystem of this area.Pinus tabulaeformis in this area is about38years old in average of this area,stand density is800-1200tree/hm2, gradient is about50°,height above sea level is about500-800m,average annual temperature is about6-7℃,annual precipitation is about500mm.On the basis of mathematic and theoretic methods,the rightness sample radius is7.5m.the number of central tree is328in three sample plot’s or all Pinus tabulaeformis in three samples, edge effects eliminated by shifting methods.All the trees in this area is competitieve trees,also i ncluded the trees obtained from shifting.To enhance the accuracy of the competition index,we selected the best individual competition index from nine indexes related or unrelated to distances.This index is CI1(CI1=the DBH of the central tree xthe average distance of the nearest eight tree/the average DBH of the nearest eight tree)The DBH individual competition model of the Pinus tabulaeformis is:CI1=-0.285D+0.003D2-0.0002D3, R2is0.944; the hight model is CI1=-0.755H+0.018H2, R2is0.885; the crown model is CI1=-1.172C, R2is0.887according to error percentage testing method,accuracy is about96.397%,according to regression method this models also proper.