Logging in East Kalimantan: volume assessment and impact on the residual stand

In the framework of STREK activities in the Berau area (East Kalimantan), the effect of logging was investigated both in terms of commercial volume and impact on residual stems. Through a 12 permanent sample plots device, set up I virgin forest, logging treatments, made of usual practices as damage control operation, were assessed thanks to a pre- and post-harvesting system including stand inventory and disturbed areas mapping. For this lowland mixed dipterocarps forest, the gross stumpage volume extraction reached in mean 87 m3/ha for a mean commercial volume of 47 m3/ha (i.e. 53.5 % of the stumpage volume). Regarding the damages generated on the stand, it was demonstrated that the felling operation created mainly injuries meanwhile skidding plaid an important role in the mortality. In mean, 21 % of the stand were injured whereas around 19 % of the original stand were destroyed mainly during skidding. Globally, it results that 40 % of the trees (10 cm to up in diameter) have been affected by logging (i.e. injured or dead). However, the control logging trials set up by STREK confirmed the real possibility to reduce the damages from 25 % to 30 % : the planning of harvesting operations, a wise resource extraction level, linked to a skidding road network optimization and a skilled staff induce favorable and no more expensive conditions to fulfill the prerequisite of sustainable management. (Résumé d'auteur