南京紫金山毛竹平均胸径与立株度之间的关系

Relationship between the Mean Diameter of Breast Height( DBH) and the Number Per Unit Area of Moso Bamboo Stands in Zijin Mountain

在紫金山毛竹纯林选取30个10 m×10 m的样地,调查每株毛竹个体胸径的大小,使用正态分布函数和威布尔分布函数判定其分布类型,先对毛竹平均胸径和立株度数据对数转置后进行线性回归,探究毛竹平均生物量和竹林密度是否遵从自疏法则。结果表明:紫金山毛竹胸径符合威布尔分布函数,毛竹的平均胸径服从自疏法则,当立株度增加时,毛竹平均胸径趋于减少。从立株度和平均胸径关系综合来看,当紫金山毛竹平均胸径为9.5 cm,竹林密度为3 276株/hm2时,紫金山毛竹林布局合理,具有较高的观赏价值。

In this study,30 sites each 10 m × 10 m in the moso bamboo pure forests were investigated in Zijin Mountain,and the DBH of every bamboo was measured. The Normal and Weibull distribution functions were used to judge the distribution type of pooled bamboos' DBHs.After log-transforming the data of mean DBH and corresponding density,the linear regression to examine whether the DBHs of moso bamoo follow the self-thinning law was used. The results showed that the DBHs of moso bamboo in Zijin Mountain follow the Weibull distribution function,with a median of 9. 1 cm. There was a significant self-thinning relationship between the mean DBH and spatial density( namely the number per unit area),that was,with spatial density increasing,the mean DBH continuously decreases. When the mean DBH was predicted to be9. 5 cm,and the spatial density reached 3 276 hm2. Such a standard of density arrangement was recommended in this area because bamboo was then of high ornamental value based on the trade-off between the number per unit area and the mean DBH.