The Yield and Biomass Structure of Plywood Forest of Poplar Clone I-69

Based on the survey data of 290 valuation areas, analyzed laws of yield and biomass structure with the change of site index and planting density. The results show that yield of plywood timber increases with increase of site index. The percentage of plywood timber to total yield decreases with increase of planting density in the site indices 14,16 and 18 m; But in the site indices 20 and 22 m, the percentage is basically steady of 50 percentage or so. Both yields of ground wood timber and chemical pulp timber increase with increase of site index and planting density. The percents of ground wood pulp timber yield to total yield and chemical pulp timber yield to total yield increase with increase of planting density in site indices 14,16 and 18 m; But in site indices 20 and 22 m, the percent is steady at 30 and 20 percent respectively. The ratios of stem, bark and branch biomass to total biomass of stand and individual tree are basically steady in different site index and planting density. It is most feasible to manage plywood forest for poplar clone I 69 with space 8 m ×8 m or 7 m × 7 m and site index 20 or 22 m.