初植密度对小黑杨人工林生长和材质的影响以及材质评价模型的建立

为研究不同初植密度对林木生长和材质的影响，该文以小黑杨为研究对象，分析了3种初植密度下林木生长特征和木材材质的差异，并建立了基于林木特征因子的材质评价模型.结果表明:初植密度对林木生长的影响不同，随着初植密度的减小，胸径、尖削度、径高比明显增大，枝下高降低，而树高受初植密度影响不大；初植密度对木材材质影响也不同，随着初植密度的减小，抗弯弹性模量(MOE)、抗弯强度(MOR)有降低趋势，而湿心材、边材面积，幼龄材、成熟材面积，以及幼龄材、湿心材比例均明显增大；基本密度不受初植密度的影响.回归分析表明，MOE、MOR、湿心材、幼龄材面积等材质指标可用树木特征因子及初植密度进行较好地预测，而木材密度的预测效果很差 

Effects of planting density on tree growth and wood quality and modeling the wood quality of Populus × xiaohei

To investigate the effects of planting density on tree growth and wood quality, the differences in tree growth characteristics and wood quality were analyzed for Populus×xiaohei from three planting densities. Meanwhile, models for evaluating wood quality based on tree characteristics were established. Results indicated that planting density had various degrees of impact on growth characteristics. As planting density decreased, diameter at breast height (DBH), stem taper and the ratio of diameter to height increased obviously, whereas live branch height decreased. Tree height was independent of planting density. Similarly, planting density imposed different influences on wood quality characteristics: as planting density decreased, modulus of elasticity in bending (MOE) and modulus of rupture in bending (MOR) tended to decrease, while wet heartwood area, sapwood area, juvenile and mature wood area, as well as the proportion of juvenile wood and wet heartwood increased obviously. Wood basic density was basically independent of planting density. Regression analysis showed that, wood quality characteristics, eg MOE, MOR, wet heartwood area and juvenile wood area, could be estimated fairly well using selected tree characteristics and planting density as predictors, while wood basic density was hardly estimated from tree characteristics.