Logging impacts on above- and belowground forest biomass and production in Bornean lowland forests

Tropical production forests account for 49 % of total forest area in Borneo. Understanding forest recovery after logging is important for sustainable forest management. To assess above- and belowground recovery status, we investigated forest tree size structure, tree dynamics (diameter growth, mortality and recruitment), and fine root biomass and production in two selectively logged forests with different recovery periods (6 and 16 years after logging) and an undisturbed forest. We hypothesized that above- and belowground forest components would progressively recover with years after logging, but the recovery of fine root biomass and production would be much slower on skid trails than in the understory. The old logged forest was characterized by its lower frequency of pioneers (Macaranga species), lower diameter growth rate, higher mortality of small trees (DBH <30 cm) and lower recruitment rate than the recently logged forest. Fine root biomass was higher in the old logged forest than in the recently logged forest on the skid trails, but fine root biomass in the understory of both logged forests was not significantly different from that of undisturbed forest. Our results suggest that although the effect of soil compaction remained on skid trails even 16 years after logging, recovery of aboveground forest structure, tree dynamics and fine root biomass was more advanced in the old logged forest than in the recently logged forest.