Research for chemical reaction and transportation of chemical elements as a successive reaction system in forest ecosystem

酸性物质的沉积会影响森林生态系统的养分循环。本研究的目的是将养分循环系统视为一个连续的化学反应系统，通过雨水与叶、茎和土壤的流动过程，并评估酸性物质的影响。本研究利用HINOKI进行两个实验，第一个是连续实地观察，以确定干沉降对叶片表面淋溶过程的影响。结果表明，干沉降影响了阴离子在叶片表面的行为，并可能增强了阴离子在叶片表面的渗透。第二个试验是在日之木林分使用人工降雨的大规模降雨试验，将雨水的pH值调节到3.2或6.8。研究了穿透雨、树干茎流和土壤水中化学元素的浓度变化。结果表明，钾离子从叶片和茎中淋溶，钙离子被吸收到叶片和茎中。钠离子与树木表面的相互作用较小。而无机阴离子通过叶、茎和土壤的浓度变化不明显，说明有机阴离子在系统中的存在是重要的。

Nutrient cycle in forest ecosystem would be affected by deposition of acidic materials. The purpose of this study were to consider the nutrient cycle system as a successive chemical reaction system through a flow process of rain water contacting with leaves, stem and soil, successively, and to evaluate the effect of acid materials. In this study, two experiments were performed by using HINOKI.The first was the continuous field observation to determine the effect of dry deposition on leaching process from leave surface. As the results, it was recognized that the behaviors of anions on leaf surface were affected by dry deposition and their penetration through leaf surface might be enhanced. The second experiment was a large-scale rain fall experiment using artificial rain water in HINOKI forest stand. pH of rain water were adjusted to 3.2 of 6.8. The concentration change of chemical elements in through fall, stem flow and soil water were pursued. As the results, it was found that potassium ion is leached from leaves and stem and calcium ion is uptake into leaves and stem. Sodium ion has little interaction with the surface of tree. On the other hand, the change in concentration of inorganic anions through leaves, stem and soil was not found. It is suggested that the existence of organic anions is important in the system.