Abstract:The dynamics of forest ecology was studied. The pH values, electrical conductivities and concentrations of metal and nonmetal elements in rainfall, stream, throughfall and stream flow were investigated based on the data collected from a small mixed forest watershed of Pinusdensifor a siebet Zucc, Pinus thunbergii Parh and Chamaecypari sobtusa siebet Zuccex Endlat Kiryu nature reserve and a small barren watershed at Jakujo nature reserve, Ootsu, Shiga, Japan. The results show that both the mixed forest ecosystems of pine and cypress and the soil draw from granite affect the pH values and metal elements of rainfall. And the contribution of the mixed forest is greater than that of the barren. Moreover, the amount of input of most elements is larger than that of output in the ecosystem, which shows the elemental accumulation in the r elated forest ecosystem.

Key words: mixed forest； small watershed; small barren watershed; pH value; metal elements