Abstract:

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.〖