庐山针叶林雾水截留、利用机制及其生态效应

Fog precipitation (fog water, fog drip, fog interception or horizontal precipitation) has long been recognized as an important hydrological input for forest ecosystems in many mountainous environments where fog is frequent, and is very important for the water balance of the forest ecosystem. However, due to the formation process of fog is greatly affected by environmental factors, and it has high requirements to measurement methods and accuracy; most recent researches are qualitative, short of quantitative analysis, which hinder the understanding of the eco-hydrological significance of fog water. In this proposed study, with the backing of Lushan national forest ecosystem positioning observation research station, Lushan coniferous forest is selected as research object. Adopting the combination method of field measurements and laboratory simulation, through the continuous observation of Internal and external meteorological and hydrological elements, and combining the characteristics of canopy and fog, this study analysis the spatial and temporal dynamics of microclimatic characteristics in coniferous forest, and its relationship with the formation and interception flux of fog water. Stable isotopes technique will be applied to partition quantitatively the contribution of fog water to soil water and plant water uptake. The response of leaf/plant water interception, foliar water uptake and water use efficiency to fog event will be observed and analyzed through artificially control experiment. Then the eco-hydrological effects of fog water can be quantitatively estimated from two scales of leaves/plants and forests. This research will to promote the understanding of the relationship between forest and fog water, and also can provide basic data and theoretical basis for further research.

在多雾的山地森林生态系统中，雾水作为一项重要的水分输入项，对生态系统水分循环起着重大的调节作用。由于其形成过程受环境因子的影响较大，对测量手段和精度要求高；大部分研究仍只是定性描述，缺乏定量研究，关于雾水的生态水文效应的认识还不完善。本项目选择庐山针叶林为研究对象，依托庐山国家森林生态系统定位观测研究站，采用野外定位观测和室内模拟相结合的方法，通过对针叶林内外气象、水文要素的连续观测，结合林冠特征、雾特征等因子，综合分析针叶林内小气候特征的时空动态变化及其与雾水形成和截留通量的关系。利用稳定同位素的方法，量化庐山针叶林雾水对土壤水及植物水分利用的贡献；并通过控制实验，观测和分析叶片/植株水分截留、水分利用及水分利用效率对雾过程的响应变化。进而从叶片/植株、林分两个尺度，定量评价庐山针叶林雾水的生态水文效应。这将有助于促进对该区森林与雾水关系的理解，并为进一步深入研究提供基础数据。

在多雾的山地和沿海的森林生态系统中，雾水作为一项重要的水分输入，对森林生态系统的水分循环起着重大的调节作用，影响着水量平衡的各个环节。由于其形成过程受环境因子的影响较大，对测量手段和精度要求高；大部分研究仍只是定性描述，缺乏定量研究，关于雾水的生态水文效应的认识还不完善。本项目选择庐山日本柳杉林为研究对象，依托庐山国家森林生态系统定位观测研究站，采用野外定位观测和室内模拟相结合的方法，利用稳定同位素技术，深入研究了庐山日本柳杉林雾水的生态水文效应。本项目取得的主要研究成果有：（1）建立了林内外不同距离处雾水截留收集装置，并同步设置了气象因子和能见度观测系统；（2）综合分析了庐山日本柳杉林内雾水截留通量时空分布规律及其主要影响因素；（3）利用修正的Gash模型，在长时间尺度上量化了雾水对日本柳杉林截留量和净降水量的贡献；（4）基于长期观测数据，分析了庐山日本柳杉林降雨截留及其再分配比例，并深入分析了穿透雨时空变异规律及其影响因素；（5）利用稳定同位素技术和野外连续采样，分析了雾水在日本柳杉林植被-土壤中的循环过程，以及对日本柳杉水分利用的贡献。研究成果有助于促进我们对森林与雾水关系的理解，对于针叶林内雾水的水文效应及水-碳平衡关系的深入研究提供参考和数据支持。