陕西华州天然次生林林分直径结构研究

Diameter Distribution of Stands of Natural Secondary Forest in Huazhou Prefecture in Shaanxi Province

林分直径结构反映了各径级林木的株数分布。通过对陕西省华州区秦岭南麓天然次生松栎混交林典型林分设置的4个样地进行每木调查,采用Meyer方程对样地林木以及林分主要树种锐齿栎、油松、华山松直径分布进行拟合,并结合Liocourt提出的q值比率。结果表明:样地总体林木株数按径阶分布呈倒J状,相邻径阶株数比q值为1.422,锐齿栎相邻径阶株数比q值为1.441,油松相邻径阶株数比q值为1.206,华山松直径分布呈近似截尾正态分布。林分林木直径结构总体合理,作为林分主要树种的锐齿栎、油松具有异龄林林木径阶结构特征,而华山松具有同龄林林木径阶分布特征。

The diameter structure of stand reflects the number distribution of trees in different diameter classes.Four typical plots of natural secondary pine-oak mixed forest in the southern foothills of Qinling Mountains in Huazhou District,Shaanxi Province,were investigated.By fitting the diameter distributions in sample plots&main tree species of Quercus acuteus,Pinus tabulaeformis&Pinus armandii in the stand by Meyer equation,and combining Liocourt’s q ratio,it is obtained that the number distribution of total tree species is inverted J-shaped according to the diameter class and the number distribution,namely the ratio q of adjacent diameter class is 1.422 in the sample plots,the ratio q of adjacent diameter class of Quercus acutus is 1.441,the ratio q of adjacent diameter class of Pinus tabulaeformis is 1.206,and the diameter distribution of Pinus armandii is approximate truncated normal distribution.Diameter structure of the stand is generally reasonable.Quercus acuteus and Pinus tabulaeformis,as the main tree species in the stand,have the diameter structure of uneven aged forest,while Pinus armandii has the diameter distribution characteristics of the even aged forest.