降水中的PH值和金属元素在松柏混交林内变化动态

 本文以日本滋贺县大津市桐生自然保护区的日本赤松(Pinus densiflora)、黑松(Pinus thunbergii)、扁柏(Chamaecypari sobtusa)混交林小流域为研究地，以若女自然保护区内荒山小流域为对照地。通过对两个小流域为期一年的定位观测研究，测定了林外降水、流出水、穿透水、树干流中的pH值、电导率、钾、钠等14种金属元素以及硅、硼非金属元素。研究结果表明，松柏混交林生态系统和花岗岩发育形成的土壤对雨水的pH值和金属元素等均具有较大的影响，但松柏混交林生态系统对其影响大于荒山。此外，系统内大多数元素的收入大于支出，呈积累趋势。

DYNAMICS OF pH VALUE AND METAL ELEMENTS OF RAINFALL WITHIN MIXED FORESTS IN JAPANESE PINE AND CYPRESS

Based on the data collected from a small mixed forest watershed of Pinus densifora sieb. et Zucc, Pinus thunbergii Parh and Chamaecypari sobtusa sieb. et Zucc. ex Endl. at Kiryu nature reserve and a small barren watershed at Jakujo nature reserve, Ootsu, Shiga, Japan,the pH values, electrical conductivities and concentrations of metal and nonmetal elements in rainfall, throughfall, stemflow and drainage have been studied. The results show that both the mixed forest ecosystem of pine and cypress and the soil draw from granite greatly (barren) affected the pH values and metal elements of rainfall while the effect of the mixed forest was greater than that of the barren. Moreover, the amount of input of most elements was larger than that of output in the ecosystems, having a tendency of accumulation.