Effectivness of reduced impact logging to carbon stock in tropical natural forest, East Kalimantan

Abstract

The research was carried out in natural tropical forest managed by PT Inhutani II, East Kalimantan. The objectives of the research were to study carbon (C) stock in natural tropical forest after conventional logging (CL) and reduced impact logging (RIL) and to asses the effectivness of RIL based on forest carbon stock, financial and other environmental aspects. The effect of CL and RIL to the environment and carbon stock in the plots were studied using the data of three plots with each size 100 m x 100 m. The plots are placed based on purposive sampling at landing, main skiddtrail and branch skiddtrail, respectively. The results of the research showed that the potencial of commercial timber species in conventional logging and RIL were 353.51 stems/ha and 362.7 stems/ha. The number of residual stand damages caused by conventional logging and RIL were 134.67 stems/ha (38.10 %) and 85.33 stems/ha (23.52 %). The avarage of one fell tree at conventional and RIL plots caused residual stand damages 26.93 stems and 17.07 stems, respectively. The avarage of residual stand damage by one felled tree of RIL can reduce residual stand damage of 9.86 stems (36.61 %) compared with conventional logging. This indicated that conventional logging in the tropical natural forest caused heavier damage on residual stand compared with RIL. Forest C stocks were counted by allometric equation of tree. The results of the research showed that allometric equation of trees was C = 0.017597 D2.73, the forest C stock of 10 years after logging were 99.16 Mg ha-1 in conventional logging area, and 139.17 Mg ha-1 in RIL area, respectively. The average of the forest C stocks of logged over areas after RIL and CL in one cycle (30 years) were 118.20 Mg ha-1 year -1 and 75.64 Mg ha-1year-1. This research indicated, that the difference in C stocks of RIL compared with CL was 42.56 Mg ha-1 year -1. Based on financial analysis, RIL was feasible and profitable at rate interest 16 %.