Using the technique of small watershed,the hydrologic factors and hydrochemistry were measured systematically from 1989 to 1993 in tropical mountain rain forest of Jianfengling,Hainan Island,China.The annual rainfall ranged from 1822mm to 3228mm and 14.3% of annual rainfall was intercepted by the canopy layer.Runoff coefficient changed between 0.31 to 0.71 per year.Except Ca,mean contents of nutrients in internal rainfall of forest increased by 1.5-12.5 times as compared with that of rainfall per year due t...