Effects of Selective Logging Methods on Runoff Characteristics in Paired Small Headwater Catchment

Reduction of vegetative cover by forest harvesting generally increases the average surface runoff volume and peak discharge for a given area of land. Forest harvesting in tropical Indonesian rainforest is managed using a selective logging system. The purpose of this study is to find the effect of controlled selective logging technique to reduce the hydrological effect on runoff. This study was conducted in three paired small headwater catchments in natural tropical rainforest area of Central Kalimantan, Indonesia. Catchment A was an undisturbed catchment for control. Catchment B and C were treated with reduce impact logging technique in selective logging activities. Controlled selective logging activities in the catchment B and C reduced canopy cover to 30% of natural cover. Discharging hydrograph response in the logged catchment produced higher peak discharge as consequences of high surface runoff. The runoff hydrograph parameter in the three catchments showed similar response to rainfall event, and the highest response of peak discharge was in the catchment B which had largest opened area. The average of direct runoff ratio in the catchment A, B and C were 31.35%; 46.12% and 44.83%, respectively. Implementation of reduce impact logging technique was effective to control the impact of logging on the runoff responses.