The effect of the precipitation pattern of the dry season on peat fire occurrence in the Mega Rice Project area, Central Kalimantan, Indonesia

摘要

Indonesia has experienced severe tropical forest fires from a long time ago, mainly in El Niño years. However, previous studies showed that after 1997 forest and peat fires in Indonesia tend to occur every year in the dry season, even in non El Niño years. To clarify this recent pattern of incidence, we studied the fire situation in the Mega Rice Project (MRP) area, Central Kalimantan where large scale development of tropical swamp-forest has been carried out since 1996. To identify the causes of the recent severe peat fires, weather data for Palangkaraya from 1978 to 2007, hotspot data captured by the MODIS satellite, monthly Niño 3.4 sea surface temperature (SST) anomalies, and ground water level (GWL) data were analyzed. The results of the analysis clearly showed a relationship among the precipitation pattern of the dry season, GWL change, Niño 3.4 SST Anomalies, and fire occurrences. A pattern of low precipitation in the dry season decreased GWL and caused a peat fire peak in the middle of August when daily precipitation reached the minimum. These results suggest that large areas of bared peat in the MRP now has a high susceptibility to fire coupled with the precipitation pattern of the dry season.