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四川西部高山林区,地处著名的青藏高原东南缘,山高坡陡,地形复杂,新构造运动活跃,地震频繁,岩体松散,是一个比较脆弱的地区。在植被分布上处于我国东南湿润森林区向西北半干旱草原过渡地带。暗针叶林是本区主要的森林类型,这些森林多集中分布在长江上游的金沙江、雅砻江、大渡河、岷江等流域及其支流。在长期的地质历史演变过程中,本区生长着丰富的针叶树种和珍贵、稀有的动植物资源,并形成一个以森林为主体的资源生态系统,这些森林是我国西南高山林区水源涵养林的重要组成部分,而且又是四川主要的木材生产基地。它使江河流量丰沛稳定,并滋育着富饶的成都平原,成为庇护四川和长江中、下游地区的绿色长城。因此,这一地区森林植被的消长变化,对维护四川及长江中、下游地区的生态平衡关系重大。
The high mountain forest area in the west of Sichuan Province is located in the southeastern margin of the famous Qinghai-Tibet Plateau with steep mountain slopes and complex topography. The neotectonic movement is active, the earthquakes are frequent and the rock mass is loose. It is a relatively fragile area. In the distribution of vegetation in China’s southeast wet forests to the northwest semi-arid steppe transition zone. Dark coniferous forests are the main forest types in this area. These forests are mostly concentrated in the Jinsha River, Yalong River, Dadu River, Minjiang River and other tributaries in the upper reaches of the Yangtze River. In the course of long-term geological and historical evolution, abundant coniferous species, precious and rare plant and animal resources are growing in this area, and a resource-based ecological system dominated by forests is formed. These forests are water conservation forests in the southwest mountainous areas of China Important part, but also the main wood production base in Sichuan. It makes rivers abundant and stable, and fertilizes the rich Chengdu Plain, as a shelter in Sichuan and the middle and lower reaches of the Yangtze River green Great Wall. Therefore, the change of the growth and decline of forest vegetation in this area is of great significance to the maintenance of the ecological balance in the middle and lower reaches of Sichuan and the Yangtze River.