林分密度和立地对油松人工林生长的影响

Effects of different densities and site conditions on growth of Pinus tabulaeformis plantations in Beijing

以北京山区25块油松人工林样地为研究对象,调查了40年生油松人工林在不同林分密度和立地条件下的生长状况,建立了林分密度与平均胸径、平均树高、平均冠幅和单木材积之间的回归方程,相关指数都在0.9以上;以样地平均优势木的解析材料确定40年生优势木树高,按单项立地因子实际分布区间分组,进行方差分析、差异显著性检验、多重比较。结果表明:随着林分密度的增大,平均胸径、平均树高、平均冠幅、单木材积逐渐减小;北京山区40年生油松人工林密度应控制在1 500株/hm2以下;明确了北京山区油松人工林生长与立地因子的关系,初步确定了油松人工林适宜的立地条件为:低山、阴坡、有效土层厚度(A+B层)45cm以上。

Based on the data investigated from 25 sample plots in mountainous areas in Beijing, the effects of different densities and site conditions on the growth of Pinus tabulaeformis plantations were analyzed. The regression equations were established between stand density and average DBH, tree height and crown width and single-tree volume, the relevant coefficients were all above 0.9. The dominant height of 40-year-old plantations was determined in line with the analytic data of the average dominant trees. The actual dis- tribution interval of single site factor was divided into groups for ANOVA, significant difference tests and multiple comparisons. The results showed that： with the increment of stand densities, average DBH, tree height and crown width and single-tree volume de- creased gradually. Densities of Pinus tabulaeformis plantations should be controlled below 1500 trees, hm2. The relationships between growth of Pinus tabulaefarmis plantations and site factors were clarified, and such suitable site factors as low hill, shady slope and above 45cm of thickness of effective soil layer （A＋B） for Pinus tabulaeformais plantation were initially determined.