四川省石棉县森林生态系统水源涵养能力研究

Research on water conservation capacity of forest ecosystems in Shimian county, Sichuan province

基于四川省石棉县第七次森林资源二类调查成果,通过综合蓄水能力法估算了石棉县森林生态系统的水源涵养量,分析了植被类型和立地条件差异下森林水源涵养服务的特性。结果表明:石棉县森林面积合计13.27万hm2,水源涵养总量为1.06亿m3,林冠层、枯枝落叶层和土壤层涵养水源的贡献率分别为29.03%、6.72%和64.25%;冷杉水源涵养贡献率最大(42.20%),云杉次之(14.83%),竹林最小(0.15%);单位面积水源涵养量大小为云杉>冷杉>经济林,竹林单位面积水源涵养量最低(323.79 m3/hm2)。总体上,森林单位面积水源涵养量随海拔高度的增加而增大,随坡度的增加而降低;全县水源涵养能力呈现出四周高、中间低的特点。根据立地条件差异合理经营管理林区,可以发挥其更大的水源涵养功能。

Water conservation service of forest ecosystems is actually the complex process of rainfall redistribution among canopy layer, litter layer and soil layer. Based on the seventh inventory results of forest resources in Shimian county, Sichuan province, this paper estimated the water conservation amount and its spatial distribution of forest ecosystems, using the method of comprehensive water storage capacity. Also, we analyzed the water conservation characteristics under different vegetation types and site conditions. The results showed that the forest area of Shimian county was 13.27 ~ 104 hm2. And the total amount of water conservation was 106 million cubic meters. The contribution rate of water conservation among canopy layer, litter layer and soil layer was 29.03%, 6.72% and 64.25%, respectively. The water conservation amount of Fir forest was the highest （42.20%）, Spruce forest came second （14.83%）, and Bamboo forest was the lowest （0.15%）. The water conservation capacity of different vegetation types in descending order was Spruce forest 〉 Fir forest 〉 Economic forest. In general, the water conservation capacity of forest ecosystems was increased with increasing altitude, while decreased with increasing slope. The distribution of water conservation capacity in Shimian county was decreased from all around to the center. As a result, reasonable management of forest region according to its site conditions differences could play greater water conservation function.