横断山区干热河谷气候及其对植被恢复的影响

EFFECTS OF CLIMATE ON VEGETAION RECOVERY IN DRY-HOT VALLEYS OF HENGDUAN MOUNTAINOUS REGION IN SOUTHWEST CHINA

干热河谷是我国西南横断山区一种特有的生态系统类型。由于气候条件和高山峡谷地形的影响以及人为干扰,植被及土壤严重退化,水热平衡失调,环境干热,植被恢复和生态治理难度极大。通过对多年来干热河谷区域植被恢复经验的总结,认为干热河谷属于我国北热带气候下的一种干热类型,具有季节性干旱的本质气候特征。在植被恢复的适宜树种选择方面,除选择乡土树种外,树种引种的相似区域应该是季节性干旱明显的热带地区。同时,该地区植被恢复应以稀树灌草为主体,通过人工促进植被恢复,充分利用雨季丰富的天然降水资源,可以在干热河谷的局部地区恢复以乔木为主的森林植被,在一定区域恢复相当面积的稀树灌木草丛植被。

Dry-hot valley is a special and typical ecological fragile area of Hengduanshan areas,southwest of China.As a result of climate,terrain and landforms of high mountain canyon and human disturbance,vegetation and soil are degraded seriously,and the balance of water and heat is broken,therefore,it is very hot and droughty,and is very difficult for plant recovery and ecological control.In the paper,based on the experiences of plant recovery of dry-hot valley,some new ideas show that dry hot valleys belong to north tropical climate of China,and are an opposite type with seasonal dry-hot property of humidity type of northern tropical climate.On the side of suitable trees selection of plant recovery,with the exception of primary trees,some introduced trees from tropical area with seasonal drought are good for it.At the same time,the main vegetation of the plant recovery area of the dry hot valley might be savanna vegetation,however,forest vegetations mainly consist of trees growing in part of dry-hot valley areas,and shrubs with rare trees vegetations growing in most of dry-hot valley areas.Most of rainfall resources in rainy season could be better utilized with the help of human activities of vegetation recovery.