泡桐胶合板材林最适经营密度及主伐年龄研究

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

通过对４０３块兰考泡桐外业调查资料的分析，发现兰考泡桐的直径分布可用Ｌ－ＰＲＭ进行预测；林分平均直径、任意高处的直径、单位面积胶合板材、檩材、椽材出材量可用建立的平均直径预估模型、干曲线方程、出材量预估模型进行预测。经检验其预测的精度能满足生产上的实际需要。用胶合板材出材量和内部收益率综合评价得出：４０立地指数级林地培育大中径级、中径级胶合板材的最适造林密度分别为每公顷２００株和２５０株，主伐年龄为１３ａ，每公顷胶合板材出材量分别为７６．３７、８１．３９ｍ３，内部收益率分别为３６．１４％、３４．６６％；３６立地指数级林地培育中径级胶合板材的最适密度为２００株／ｈｍ２，主伐年龄为１３ａ，每公顷胶合板材出材量为５３．２１ｍ３，内部收益率为３０．８２％。

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.elonga-ta 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 thepractical demands.The conclusions drawn by the comprehensive evaluation on plywood tim-ber yield and ecnomic benefit are as follows :(1)for site index 40,the optimum densities formiddlelarge, middle diameter class plywood-oriented P. elongata plantation are 200 and 250trees 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.