小陇山油松天然林结构特征

利用固定样地每木定位调查数据和相关分析统计软件,对小陇山林区油松天然林的结构特征进行了分析。结果表明:油松天然林树种组成丰富,群落中共出现18个树种,油松占绝对优势,但样地树种隔离程度较低,属于弱度混交。油松天然林的直径分布为多峰山状曲线,油松种群的直径分布近似于正态分布,可用3参数Weibull分布拟合;树高随胸径的增大而增加,胸径与树高的关系可运用幂函数进行拟合。林分中油松个体的胸径、树高和冠幅的大小分化差异明显,整体上表现为中庸状态;油松天然林林木分布格局为随机分布,油松种群分布格局也为随机分布。

Structure Characters of Pinus tabulaeformis Natural Forest on Xiaolong Mountain

The structure characters of Pinus tabulaeformis natural forest on Xiaolong Mountain, Gansu Province was studied by fixed sample survey of each tree positioning data with statistical software, the result showed that the tree composition of Pinus tabulaeformis natural forest was abundants, there had 18 tree species in community dominated by P. tabulaeformis, however, the degree of tree species segregation was lower and the average value of mingling was weak. The diameter at breast height (DBH) distribution of forest stand followed a multi-shaped peak curve and the DBH distribution of P. tabulaeformis population approximated to normal distribution and it was well fitted by Weibull function, the tree height increased with the tree DBH increasing and the relationship between tree height and DBH was well fitted by power function. The individual size of DBH, tree height and crown width of P. tabulaeformis in stand was significantly differentiated; the average state belonged to medium. Both the horizontal distribution patterns of stand and P. tabulaeformis population were random distributed.