Biomass recovery of naturally regenerated vegetation after the 1998 forest fire in East Kalimantan, Indonesia

Abstract

After the 1998 forest fire in East Kalimantan, Indonesia, biomass recovery of naturally regenerated vegetation was estimated in order to evaluate the initial secondary succession patterns of the burned land. We established research plots in naturally regenerated vegetation that included pioneer tree species, and the dominant pioneer species were Homalanthus populneus, Macaranga gigantea and M. hypoleuca, Mallotus paniculatus, Melastoma malabathricum, Piper aduncum, or Trema cannabina and T. orietalis. Annual tree censuses over 4 years (from 2000 to 2003) showed that on plots where the initially dominant tree species were M. malabathricum and T. cannabina and T. orietalis, they tended to disappear, and were replaced with M. gigantea and M. hypoleuca. In contrast, on plots where the initially dominant species were M. gigantea and M. hypoleuca, M. paniculatus, or P. aduncum, they continued to dominate 5 years after the fire. We classified tree species that were initially dominant but disappeared within 5 years after the fire as extremely short-lived tree species. The aboveground biomass of trees (AGB) averaged 12.3 Mg ha-1 (ranging from 9.2 to 17.0 Mg ha-1) in 2000 and 15.9 Mg ha-1 (ranging from 7.4 to 25.0 Mg ha-1) in 2003. Between 2000 and 2003, some plots exhibited an increase in AGB and some a decrease in AGB. In the plots dominated by M. gigantea and M. hypoleuca, the AGB increased to over 20 Mg ha-1, but other plots accumulated significantly less AGB in the 5 years following the fire. These results suggest that the pattern of AGB accumulation in secondary forests is strongly dependent on the dominant pioneer tree species.