Abstract: The relation between water cycling and nutrient cycling was studied from, community level in the oak forest. The results showed that rainfall is a very important input of nutrient to ecosystem and the washing-leaching processes of canopy are very helpful for the return of nutrient to soil and shorting the route of nutrient cycling. As nutrient enriched stemflow is large in oak forest, the roots of oak can obtain lot of nutrient and water. This helps oak to adaptdry and meager soil. Runoff is an important output of nutrients and water to ecosystem. Because infiltration flow with low nutrient content accounts for 90% of total runoff, nutrient can be accumulated. As rainfall passes through ecosystem. its distribution pattern is varied, which causes the difference of nutrient accumulation. The effects of human interference on nutrient cycling and water cycling were also studied. It shows that clear-cuting can cause hydrological changes and loss of nutrient. In order to estimate well the ecological function of forest, it is very necessary to combine water cycling with nutrient cyclung.

Key words: water cycling, nutrient cycling, stemflow, runoff