长江上游峨眉冷杉林结构特征的研究

通过对长江上游贡嘎山不同演替阶段峨眉冷杉（Abies fabri）林的野外调查和对比分析，探讨了峨眉冷杉林的结构特征。结果表明，成熟峨眉冷杉林下有丰富的峨眉冷杉种源，小于20年的峨眉冷杉更新幼树幼苗数量少，但却为唯一的优势更新树种，在冬瓜杨、峨眉冷杉混交林中，冬瓜杨、桦木等树种在最初30年高生长非常迅速并能很快占据优势地位。峨眉冷杉是一耐荫性很强的树种，幼龄期生长缓慢，但将更替其它树种形成稳定群落。贡嘎山海拔2900－3400m地区大规模泥石流为100多年发生一次，在泥石流发生地，川滇柳、冬瓜杨、桦树等树种首先出现在迹地并占据优势，在自然条件下恢复峨眉冷杉林将需要较长时间，可通过人为干预措施加以促进和调控。

Structural characteristics of Abies fabri forests at the upper reach of Yangtze River

The structural characteristics of Abies fabri forest under different succession stages in Gongga Mountains at the upper reach of Yangtze River were studied. The results showed that in the mature Abies fabri forest, there existed abundant seeds and a few saplings of Abies fabri younger than 20 years, but only Abies fabri was the dominant regeneration species. In the poplar-fir mixed forest, the height growth of poplar and birch was very fast during first 30 years, and poplar and birch dominated rapidly over the canopy.Abies fabri had a lower growth rate and a strong shade-tolerance in its first growth stage, and could replace other tree species gradually. The cycle of mud-rock flow occurrence was above 100 years in the Gongga montane areas from elevation of 2800 to 3200 m. After mud-rock flow, poplar and birch often occurred and dominated, and there were only a small number of Abies fabri saplings in slash. Under natural condition, to recover Abies fabri forest would demand a long time, but this process could be controlled and improved by human activities.