四川西部高山峡谷区森林分布特点及其演替规律

自从1950年以来,在四川西部高山峡谷区设置了700块样地,对该区域森林分布特点及森林演替与环境梯度间的关系进行研究.结果表明,高山峡谷区森林建群种以冷、云杉两属树种为优势,形成90多种森林类型;冷杉林多分布于各河流及其支流的中、上部,而云杉林多分布于宽谷地带和半阴半阳坡;冷云杉林冠下天然更新不良,而林窗天然更新效果较好;森林演替与垂直梯度关系密切;演替途径与原林型林下植被层片有关;人为措施可以促进或延缓演替进程;扩张更新效果常受地形、植被、风向影响。图4参9。

Distribution characteristics and succession regulation of the forests in alpine and canyon region of western Sichuan Province, P. R. China

Since 1950, 700 plots were established in the alpine and canyon region of western Sichuan. The distribution charac-teristics and the relationships between forest succession and environmental gradients were studied. The results showed that the main tree species were Picea and Abies in this region, and there were more than 90 forest types. Abies forests mainly dis-tributed in the middle and upper reaches of rivers and their branches, and Picea forests mainly distributed in wide valleys and on half-shaded and half-sunny slopes. The natural regeneration was poor under primitive spruce and fir forest canopy, but was good in the spruce and fire forest gap. The relationship between forest succession and vertical gradient was closely related to the relationship between forest succession procession and plant synusia under primary forests. Human activities could promote and postpone succession process. The results of expanding regeneration were often influenced by topography, vegetation and wind direction.