关键词: 水源林, 生态系统, 结构与功能, 冻土水文, 定位研究

Abstract:

According to the dynamic changes of the structure and function of water conservation forest ecosystems in Qilian Mountains, making studies on forest microclimate and hydrological effect. The result shows that the water conservation forest in Qilian Mountains not only has the function of blocking and storing precipitation,reducing temperature range,keeping more soil humidity,but also has the hydrological effect of soil and water-source conservation. The annual low flow runoff volume increased 28.87mm in forest coverage of 65 percent than of 32 percent, but annual flood runoff volume reduced 98.87mm. Water storage in forest soil is from 298.32mm to 391.93mm, but 182.09mm in glassland. The surface runoff seldem forms in forest land. The annual soil loss is 1793.9kg/hm² in grassland. Perennial and seasonal frozen earth make the runoff coefficient is 0.73 in frigid mountion area,the fewer evaporation is 156.54mm.Many years' monitoring data shows in Qilian Mountain the quality of stand is declining, the glacier is shrinking back,the runoff volume is reducing every year,the ecologic environment is worsening. So we suggest that government departments at different levels should think highly of the problem of ecologic protection in Qilian Mountains.

Key words: Forest for water conservation, Ecosy stem, Structure and function, Frozen earth, Fixed observation