以藏东南林芝地区高山松天然林为研究对象,在米林县、巴宜区、波密县等主要分布区内设置56块标准地,共2 041株高山松立木进行每木检尺,研究了高山松胸径DBH(D)与冠径(Cd)的相关关系。结果表明,高山松的胸径与冠径有极显著的相关性,林木冠径和胸径的最佳回归模型为二次函数Cd=-0.001D²+0.244D+0.184。冠径与胸径的比值随着胸径的增长而呈现下降的趋势,初始阶段(0~20cm)Cd/D值下降较快,但之后随着胸径的增长两者比值变化较为缓慢,趋向平稳,其比值在20左右。林木冠径胸径比(Cd/D)与胸径D之间呈对数函数关系Cd/D=-4.473ln(D)+36.098。此外,该研究在胸径冠径相关关系的基础上编制了高山松各径阶下林分的适宜经营密度表,确定了调查地区现有天然林的间伐强度,为高山松树种的造林设计和经营规划提供了参考数据。

2 041 standing trees were measured from 56 sampling plots in Milin County,Bayi District and Bomi County,where is the major distribution area of Pinus densata in Tibet.The aim of this study was to establish the relationship of diameter at breast(D)and crown diameter(Cd)of P.densata natural forest in the southeastern Tibet.The result showed that the Cd had a significant correlation with the D.The optimal regression model of Cd with D was Cd= -0.001D²+0.244D+0.184.The Cd/D ratio decreased as D increased,and dropped rapidly at initial stage(D=0~20 cm),beginning to stabilize at around 20 in trees bigger than 20 cm dbh.The optimal regression model of Cd/D with D was logarithmic function Cd/D=-4.473ln(D)+36.098.Besides,according to the regression of Cd and D,the optimal management density table under different diameter classes has been established.It not only helps to determine the thinning intensity but also provides references about tree number in the afforestation design and forest management planning in this region.