华山松大小蠹幼虫分布状态及最佳抽样模型

Distribution and Optimal Sampling Model of Larval Dendroctonus armandi

在陕西省留坝县的华山松(Pinus armandi)林区,对华山松大小蠹(Dendroctonus arman-di)种群密度、分布状态和抽样模型进行了研究.结果表明:华山松大小蠹幼虫密度在华山松树干1～10 m高度范围内各不相等;危害致死华山松成年树的华山松大小蠹种群密度为23.2～52.8头·dm-2,平均37.4头·dm-2;平均值与树干4 m高处样方虫数均值接近;华山松大小蠹幼虫在树干上集中分布于树干7～8 m高处.

The population density,distribution,and sampling model of a bark beetle,Dendroctonus armandi,on Huashan conifer,Pinus armandi,were investigated in a forest stand located in Liuba County,Shaanxi Province,China.The results indicated that larval density at a height on the trunk of the trees was different from that at other height within 1 to 10 m;Larval population that caused a mature tree to die averaged at 37.4 larvae·dm-2,with a range of 23.2 ~ 52.8 larvae·dm-2;the average of the sample means was close to that of the sample units taken at the height of 4 m on the trunk;The actual and the estimated peaks appeared at the heights of 7~8 m.