森林植被的水分自营作用及其观测试验论证方法

The Water Self-supporting Effects of Forest and Its Field Experimental Verification

作为陆地生态系统的主体,森林对地表圈层的水循环产生了重要的影响,其涵养水源、防止水土流失和维持水质的作用为多数学者所公认,但是对于森林是否增加或减少河川径流量,在学术界还存在较大的争议。作者根据国内外学者在森林水文效应方面的观测结果和理论分析,提出了森林植被的水分自营作用理论。该理论认为,森林具有对环境的正向改造作用,森林植被通过对林区水分分布场的自主营造(改造)机制来增加林地的有效水分供应,改善林区的水文气象环境,创造出有利于森林植被生存的条件,同时引起河川径流量的增加或者降低。森林植被的水分自营作用理论比较好地综合了森林影响径流形成的各个因素,能够统一解释森林水文效应中相互矛盾的试验结果。为了更进一步地认识和完善该理论,为森林水文效应评价服务,还提出了验证该理论的野外观测试验方法,包括典型森林区辐射能量和水分通量的精细测量、森林流域分布式蒸散发计算模式研究、森林水分调节的主要环节及其计量标定、林地水分调节关系解析和森林生态系统水文过程模拟。

As the main body of the terrestrial ecosystem, forests play an important role in the water cycle of the epi- geosphere. It is generally acknowledged by the scholars that the forest has such ecological functions as water and soil conservation ,water resources conservancy and water quality improvement. However, it is still controversial in the academic circles whether forests increase or decrease the stream flow. Based on the extensive domestic and for- eign observation and theoretical analysis in the field of hydrological effect of forest, a hypothesis which is called wa- ter self-supporting effects of forest was propounded. The hypothesis holds that forests can postively improve water environment. Forest vegetation can add available moisture supply to woodland, modify the forest hydro-meteorologi- cal conditions, and create favorable living conditions for plant survival through self-building/adjusting the water dis- tribution of the forest ecosystem,leading to the increase or decrease of the river runoff. The hypothesis synthetically consider the various factors affecting runoff formation in forest ecosystem and also can systematically explain the contradictory experimental results in hydrological effects of forest. To further understand and perfect the theory and contribute to forest hydrological effects assessment, some experiment verification methods, such as accurate measure- ment of radiation energy and water flux in typical forest, researches on distributed forest watershed evaporation cal- culation model, studies on the key links of the water self-adjusting effects of forest and its quantification, analysis on water self-adjusting relations in forestland ,and hydrological process simulation of forest ecological system,were pro- posed.