Study on Optimum Management Density and Crop Age of Plvwood-oriented P.elongata Plantation

Through the field survey and analyses of total 403 Paulownia elongata stan-dard san1pling plots,it was discovered and concluded that the DBH distribution of P.elongata stand can be predicted by L-PRM. Stand mean DBH diameters at free heights,timberyield of plywood,purlin and rafter in unit area can also be predicted by the models of standmean DBH,stem curve, and timber output.The predicting accuracy checked can meet the practical demands.The conclusions drawn by the comprehensive evaluation on plywood timber yield and ecnomic benefit are as follows:(1)for site index 40,the optimum densities form iddlelarge, middle diameter class plywood-oriented P.elongata plantation are 200 and 250 trees per ha with 13 years as crop age,76.37 and 81.39 m3 per ha of plywood timber yield,36.14% and 34.66% of IRR,respectively.(2)for site index 36,the ontimum density formiddle diameter class plywood-oriented P.elongata plantation is 200 trees per ha with 13years as crop age,53.21 m3/ha of plywood timber yield,30.82% of IRR.