森林植被对降水水化学的影响

综述了森林植被各个层次对降水水化学影响的主要研究成果,并指出了目前该方面研究存在的问题及今后需要努力的方向。大量集中在乔木层的研究表明,与林外雨比较,穿透雨、树干茎流中多数元素的浓度均呈增加的趋势,浓度大小的总趋势为树干茎流>穿透雨>林外降雨,K、Mg、Mn等表现突出,浓度可增加10倍以上;影响元素浓度变化因素包括降水特征、林分类型、大气状况等;具体到某一种元素,不同区域、不同林型间研究结果差异很大,很难得出一致的结论。对灌草层和枯落物层吸附淋溶作用研究较少,也就不能正确评价森林植被对降水水化学的综合效应。因此,在空间尺度上,要加强不同区域森林植被各个层次的研究;在时间尺度上,短时间的观测缺乏代表性,长期定位观测更具科学性。此外,目前的研究,尤其是国内的研究,只是对现象的揭示,缺乏过程及机理的深入研究,限制了我们对森林植被的内在运行机制和客观规律的正确认识。

Effects of forest vegetation on water chemistry of precipitation

This paper summarized the main researches on the effect of the forest vegetation on the water chemistry, and points out the main problems existing at present and the prospects of the future research. A great many researches focusing on the tree layer showed that the element contents of the through-fall and the stem-fall comparing with the precipitation increase, and the general order of the contents is stem-flow>through-fall>rainfall. The allocation process was influenced by many factors, such as precipitation characters, forest types and air pollution. To a specific element, research results displayed that the contents of elements in rainfall, through-fall and stem-flow varied greatly in different areas or different forest types. It is difficult to draw a conclusion. The insufficient works on the layers of shrub-grass and litter can not make us to understand the synthetical effects of the forest vegetation on rainwater chemistry. So, long-term observations for studying the leaching of every layer of vegetations are very necessary. At present, most researches focus on the phenomenon explanation and neglect the processes and mechanisms, which restricted us to understand the mechanisms and the objective law.