Abstract
Borneo is in the hunlid tropics, but there have been periodic long and severe dry spells since the prehistoric era, especially in eastern part of the Island. The dry spells usually related to EI Niño Southern Oscillation (ENSO) events. Two of the world’s largest forest fires, occurred in 1982-83 and 1997-98, during severe droughts related to strong ENSO events. Both of the fires affected about 5 million hectares of land ares in eastern part of the Island. The recent increase in human activities as well as extent of grassland led to extensive and repeated wildfires during the dry spells. The damage in the 1982-83 fires was greater in logged-over secondary forests than in primary forests. After the fire, the severely burned forests were dominated by pioneer tree species; growth of Macaranga triloba and Macaranga gigantea was definitely promoted by the fire. The 14-year interval between the large wildfires in 1982-83 and 1997-98 was not sufficient for forest recovery. Subsequently, tree mortality in 1997-98 fires was higher in the stands where the logging intensity and fire disturbance in the past were high. In order to conserve the remaining forests and to rehabilitate the burned forests, the occurrence of forest fires must be diminished.
