在陆生植被中,森林具有最大的水源涵养功能,是一个面积宽广的绿色水库。即便在降雨丰沛的热带地区,森林的破坏也会造成严重的水源枯竭。如广东省海南岛的松涛水库,库区原有水源林140多万亩,后减少了75％,使水库的枯水径流量减少了50％。由于森林一般都具有林冠层、下木及活地被物层、地表枯枝落叶层和根系土壤层,这些层次对阻截降水,调节径流,贮蓄水分,能 Among the terrestrial vegetation, the forest has the largest water conservation function and is a green reservoir of wide area. Even in heavily rainfall-prone tropical areas, deforestation can cause severe water depletion. For example, the Songtao Reservoir in Hainan Island, Guangdong Province, contains more than 1.4 million mu of original water source forests in the reservoir area and a decrease of 75% thereafter, resulting in a decrease of 50% in the runoff of reservoirs. As the forest generally have canopy layer, wood and living layer, surface litter layer and root soil layer, these layers to intercept precipitation, regulate runoff, storage of water, can