2011, 24(5): 659-662.
In this study, Picea schrenkiana var. tianshanica forests in five different longitudinal sites (Zhaosu, Gongliu, Wusu, Urumqi and Hami) in Tianshan Mountains were investigated by using vertical transects. The percentage of trees in different sizes, the diameter classes distribution, and the fitted equations for accumulated stem percentage of P. schrenkiana var.tianshanica were analyzed in order to study the population diameter classes structure. The results showed that the decreasing order for percentage of seedling,sapling and the small trees is Hami, Urumqi, Gongliu, Zhaosu and Wusu.The distribution of stem abundance along the diameter classes in Zhaosu, Gongliu, Wusu, Urumqi and Hami all had an inversed "J" shape. The best fitted equation in Zhaosu and Urumqi for accumulated stem percentage of P. schrenkiana var.tianshanica was exponential,while the best one for another three sites was logarithmic.Gongliu preserves the best natural populations of P. schrenkiana var. tianshanica in terms of various size class analysis indexes.