金沙江干热河谷植被恢复探讨

从气候、土壤蓄水能力及植被演化历史等方面论述金沙江干热河谷植被恢复的基本原则、途径及方向.分析认为:金沙江干热河谷目前的植被状况是该区气候变迁的结果,但人为干扰加速了植被的逆向演替进程;旱季水热的非同步性是植被恢复困难的根本原因;微生境的气候差异,特别是旱季蒸发量的差异是影响植被状况的外在因素,但旱季土壤中的有效水贮量和消耗速度是决定因素;所有节水技术必须以提高旱季土层的有效水数量为核心,如改善土壤的结构、提高土壤水源涵养能力、增加土壤入渗能力、减少土壤蒸发;该区的植被恢复方向应以形成稳定的植被群落为目标,并以近自然林为参照,采取"适度"造林和合理的节水技术,以提高植被恢复成效.

Study on Vegetation Restoration in Dry-hot Valleys of the Jinshajiang River

The fundamental principles,approaches and orientation for vegetation restoration in the dry-hot valleys of Jinshajiang River were discussed according to the climatic feature,water holding capacity of the soil and the history of local vegetation succession.The main conclusions were as follow: The characters of current vegetation in the dry-hot valleys mainly resulted in the climate change as the elevation rising,but anthropogenic activities accelerated the converse succession course of local vegetation.The non-synchronization course between the increases of rainfall and temperature was the major reason to cause the difficulties for vegetation restoration in the area.The difference in micro-climate conditions,especially the difference in evaporation was the external factor to cause the vegetation change,while the storage of available soil water and the soil moisture consuming velocity were the two decisive factors to determine how well the plants could grow in the dry season.Maintaining effective soil moisture in the summer might be the critical problem for vegetation restoration that could be realized by a number of water saving approaches including soil structure amelioration,promotion of water holding capacity of the soil,enhancement of water infiltration into the soil,and evaporation reduction by surface soil.The orientation of vegetation restoration in the dry-hot valley should be to form stable plant communities by referring to close-to-nature forestry principles and moderately taking silvicultural and water saving techniques to improve the restoration effect.