关键词: 元谋干热河谷, 森林消长, 生态环境变化, 森林植被恢复

Abstract: In Yuanmou dry-hot valley, the forest cover rate is respectively 12.8% in 1950(In the early 1950s, above 2 000 m of the altitude in Liangshan area, there distributed Pinus yunnanensis forest, the forest cover rate reached 60%~70%. Between 1 500~2 000 m,still distributed tract Pinus yunnanensis forest.), 6.3% in 1973 (Because of the serious destruction during the periods of the "Great Leap" and "Cultural Revolution", the forest area reduced greatly), 5.2% in 1985 (After 1978,because of the need of economic development, the forest was felled again) and 5.8% in 1993 (After 1985, energetically plant trees, the forest cover rate increased slightly). The human socio-economic activity (felled trees and plant trees) is the main cause of increase and decrease of forest area. The increase and the decrease of the forest area is the key of the eco-environment changes to good or bad condition (The decrease of forest area caused eco-environment worse. The drought and flood are gradually serious and the land desertification developed). Against forest decrease and eco-environment deterioration some countermeasures have been proposed to recover forest vegetation and improve eco-environment, i.e, strengthen young trees management and tending, close hills to facilitate afforestation and change slope cultivated land to afforestation; formulate favourable policy; rationally dispose tree species; use water-saving technique in afforestation.

Key words: Yuanmou dry-hot valley, forest increase and decrease, eco-environmental change, forest vegetation recovering