Temporal changes in small particle sediment yielded from the catchment following to forest growth after clear cutting

Landscape change caused by forest disturbance would be expected to influenc e on the acceleration of soil erosion of hillslopes. Most of the soil erode d from a hillslope flow through the stream channel and out of the catchment as fine particle sediment such as suspended load (Chikita, 1996). In this study, temporal changes in the volume of fine particles yielded from small catchments were monitored at five catchments varying from 2.2 ha to 4.2 ha in area, 10.1 degrees to 17.2 degrees in slope, and 5 years to 70 years (al most secondary forest) in elapsed time after clear cutting. The volume of s ediment transported by stream flow, which was trapped in a couple of sample r boxes set up at the mouth of each catchment, was measured every month for five months. The result shows that the amount of the fine particle sedimen t of two catchments elapsed 15 to 18 years after clear cutting was larger t han that of the other catchments elapsed 3 to 6 years after clear cutting. Furthermore, the volumetric peak of fine particle sediment yielded first ap peared during 10 and 15 years after clear cutting. From the results, the in fluence of the clear cutting on the volume of small particle sediment yield ed from a catchment tend to appear after a time elapse of 10 to 15 years fo llowing clear cutting.