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 influence on the acceleration of soil erosion of hillslopes. Most of the soil eroded from a hillslope flow through the stream channel and out of the catchment as fine particle sediment such as suspended load. 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 degree to 17.2 degree in slope, and 5 years to 70 years (almost secondary forest) in elapsed time after clear cutting. The volume of sediment transported by stream flow, which was trapped in a couple of sampler 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 sediment of two catchments elapsed 15 to 18 years after clear cutting was larger than that of the other catchments elapsed 3 to 6 years after clear cutting. Furthermore, the volumetric peak of fine particle sediment yielded first appeared during 10 and 15 years after clear cutting. From the results, the influence of the clear cutting on the volume of small particle sediment yielded from a catchment tend to appear after a time elapse of 10 to 15 years following clear cutting.