不同密度下杉木生长动态与主伐期预测OA

Based on the analysis of 5-year continuous monitoring data of sample plots with different initial planting densities in Xianning City,Hubei Province,three nonlinear growth models-Richards,Logistic and Gompertz-were adopted to fit the in-dividual tree volume growth process.This study explored the effects of different initial planting densities on the growth char-acteristics,volume accumulation and final felling age of young Cunninghamia lanceolata(Lamb.)Hook.stands.The re-sults showed that the initial planting density had a significant effect on the growth dynamics of young C.lanceolata forests.With the decrease of initial planting density,the diameter at breast height(DBH),tree height and individual tree volume all showed an increasing trend.The low initial planting density treatment was more conducive to individual tree growth,and this effect became increasingly obvious after the 5-th year.In contrast,the stand volume per unit area increased with the rise of initial planting density,indicating that the high initial planting density treatment was more favorable for early-stage total volume accumulation.Among the three models,the Richards model exhibited the highest fitting accuracy,with the coefficient of determination(R2)ranging from 0.98 to 0.99.Meanwhile,it achieved the optimal values of root mean square error,mean absolute error and Akaike information criterion(AIC),thus being suitable for the growth prediction of C.lan-ceolata.The analysis of final felling age indicated that with the reduction of initial planting density,the maximum mean an-nual increment(MAI)of individual trees increased significantly,and the final felling age was delayed.For the treatment with an initial planting density of 2500trees·hm-2,the maximum MAI of individual trees reached 0.0109m3·a-1,the maximum MAI per unit area was27.36m3·hm-2·a-1,and the final felling age was13.17years.As for the treatment with an initial planting density of 6667 trees·hm-2,the final felling age was 8.81 years,which was suitable for short-rotation small-diameter timber management.In conclusion,the high initial planting density treatment is conducive to rapid volume accumulation and fits short-rotation management,while the low initial planting density treatment is favorable for cultivating high-quality large-diameter timber and improving long-term economic benefits.