Abstract
This study was conducted to clarify the forest function of floods modulation through the relationship between rainfall and peak flows in the three kinds of forest type. The experiment sites in Gwangneimg include the natural mature deciduous and planted young coniferous forests. Also the rehabilitated mixed forest locates in Yangju, Gyeonggi-do. Hydrologic data includmg ramfall, discharges have been measured in the gauging weirs from 1982 to 1999. About 110 storm hydrographs for each site were selected for the purpose of analyzing the amount of rainfall to peak flows and peak flow rates. Peak flows in the planted young coniferous forest increased suddcnly as the amount ot' rainfall to peak increased over 100 mm as a threshold value. On the other hand the rehabilitated mixed forest showed the theshold value of 50 mm dfference of threhold values in two forests resulted form conditions of forest structure and soil. Peak flow rates of the natural mature forest deciduoas increased very gradually ro 200 mm rainfall uwing tu goudconditions of forest structure and soil. in case of the planted young coniferous forest, the slope of relation forest showed no difference considerably in July 1993 compared in July 1983. The result above reflects the fact that foresi development improves the forest function of peak-flows modulation