Effects Of The Factors On Under Brach Height And DBH Of Phyllostachys Pubescens Mazel

Phyllostachys pubescens Maze Originated in China,it generally distributes in China, it is a major economic bamboo species. From the view of Bamboo Forest Ecology, based on the Software of EXCEL, SPSS and MATLAB, and surveying data of the fifty sample plots of Phyllostachys pubescens Mazel in Yixing district of Jiangsu province, the effects of gradient (X₁), aspect (X₂), slope position(X₃), humus thickness(X4), canopy density (X₅)and density(X₆) on the increment of Phyllostachys pubescens Mazel were analyzed,and setting up under brach height and DBH's mathematical model.The results show that:(1) We used the six site factors to make partial correlation analysis and stepwise regression analysis, the result showed the canopy density (X₅), slope position(X₃) and density(X₆) were the main factors on growing of under brach height The mathematical model: Y₁=2.293+0.412X₃+2.987X₅-4.294X₆(2) We used the six site factors to make partial correlation analysis and stepwise regression analysis, the result showed the canopy density(X₅), density(X₆) and slope position(X₃) were the main factors on growing of DBH. The mathematical model: Y₂=6.937+0.555X₃+ 5.528X₅-10.188X₆(3) If the same density of Phyllostachys pubescens Maze, aspect is the main factor on canopy density.(4) Then taking the six site factors principal analysis, make the six variables turn to three principal components, and this three components'cumulative proportion got to 86.1%.(5) Setting up under brach height (Y1) and DBH's(X) mathematical model: Y₁=-0.744+0.542X, Multiple correlation coefficient R=0.949,it Reached a significant level.