二十多年来,天山林区的更新树种基本上是单一的云杉.云杉在幼龄期需要遮荫,营造纯林,由于生境关系,生长极慢,十年只有一米左右,还超不过牲畜的咀巴,保护困难,成活保存率低,这是更新成效不大,欠账多的原因之一.云杉纯林是天山森林顶极群落之一,活立木蓄积占百分之九十以上,更新以云杉为主,这是对的.但这些年单一的营造云杉纯林的实践证明,效果并不 For more than two decades, the regenerated tree species in the Tianshan forest area have basically been single spruce, and the spruce need to be shaded in the young age to create a pure forest. Due to the habitat relationship, sparse growth is only about one meter in ten years. One of the reasons for the poor success and lack of credit is that the spruce forest is one of the forest climax communities in Tianshan, Ninety or more, the update to spruce-based, this is right, but these years a single practice to create pure spruce forest, the effect is not