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Impact of the 1997 Fires on the Peatlands of Central Kalimantan, Indonesia, 8-2000

in Sustaining Our Peatlands:
Proceedings of the 11th International Peat Congress in Quebec, Canada, Aug. 2000;
eds L.Rochefort & J.-Y. Daigle, pp.962-970
Page, S.E. 1), Rieley, J.O. 2), Boehm, H-D.V. 3), Siegert, F. 3), & Muhamad, N.Z 2) 

1: Department of Biology, University of Leicester, Leicester, LE1 7RH, U.K. tel: +44 116 2525923, fax: +44 116 2523330;
2: School of Geography, University of Nottingham, Nottingham, NG7 2RD, U.K. tel: +44 115 9515449; fax: +44 115 9515248;
3: Kalteng Consultants, Kirchstockacher Weg 2, D-85635 Hohenkirchen, Germany. tel: +49 8102 774848; fax: +44 8102 774850;

Keywords: tropical peatland, forest, fire, remote sensing, carbon emissions

The area of peatlands in Indonesia is approximately 20 million hectares (Mha), which is nearly 11% of the total land area (Rieley et al., 1996). The vast majority are lowland, ombrogenous systems that support a natural vegetation of peat swamp forest on top of peat that ranges from 0.5 m to more than 10 m thick (Rieley & Ahmad-Shah, 1996). Approximately 50% of these peatlands exceed 2 m in thickness (Anderson, 1983). Almost all of Indonesia's peatland is located in three large islands, Borneo (Kalimantan), New Guinea (Irian Jaya) and Sumatra. Central Kalimantan province contains about 3 Mha of peatland and studies have been carried out on the ecology and environmental importance of the peat of this area since 1993. This research was well established therefore when Indonesia was affected by the 1997 El Niño-Southern Oscillation (ENSO) event and provided the opportunity to observe and measure some of its environmental consequences.
The climatic changes brought about by ENSO events have global consequences, but effects are particularly pronounced in Indonesia and other parts of the Western Pacific where drought conditions may be produced as a result of the greatly extended dry season compared to 'normal' years. Over the last three decades ENSO events have occurred several times, resulting in droughts of varying severity. In 1982/83 the prolonged dry season resulted in severe forest fires in East Kalimantan where more than 3 Mha of land burned, including 0.55 Mha of peat swamp forest (Johnson, 1984). There were minor droughts and less severe fires in 1987, 1991 and 1994. In Central Kalimantan, in non-ENSO years, there is a dry season of usually three or four months duration between May/June and September. Rain still falls in dry seasons but the frequency and intensity of events are reduced greatly.

During the 1997 ENSO event, the dry season, spanned eight months from March to December, during which there was hardly any rainfall. At the start of the dry season in 1997, as is normal at the commencement of every dry season in Indonesia, many fires were started in order to clear deforested land of vegetation prior to planting crops and trees. Many of these fires spread into forest areas where they burned with greater intensity. In Kalimantan, Sumatra and Irian Jaya fires started in this way were either located on, or spread to, peatland where both the surface vegetation and underlying peat were ignited. In Central Kalimantan, the situation was exacerbated by a programme of massive peatland conversion, the so-called Mega Rice Project (MRP). This scheme was initiated in 1995 with the aim of converting one million hectares of wetland (mostly peatland) to agricultural use (Notohadiprawiro, 1998).

Between January 1996 and July 1998 over 4000 km of drainage and irrigation channels were constructed throughout the area designated for the MRP and forest clearance on this land was initiated. After removal of the commercial timber, the remaining tree debris was removed by means of fire as the cheapest, most readily available land clearance tool. Various assessments have been made of the amount of land in Indonesia that was damaged by the 1997 fires. Initial estimates indicated that approximately 4.5 Mha were affected (Liew et al., 1998 quoted in Schweithelm, 1998), but this was increased subsequently to 9 Mha (BAPPENAS, 1998). Of this latter area, as much as 1.45 Mha was peatland that was either in a natural condition supporting peat swamp forest, degraded peatland with secondary vegetation, or agricultural land of farms and plantations on drained peatland. Two of the most intensive sources of smoke and particulate matter reaching the atmosphere were the fires centred on the peatlands of Central Kalimantan and Riau in South Sumatra. In both of these areas vegetation and underlying peat caught fire, contributing greatly to the so-called haze (particulate-laden smog) that drifted north and west to affect Singapore and Malaysia.

During this time solar radiation in Central Kalimantan was reduced to 40% of normal levels (H. Takahashi, pers. comm.) whilst visibility was reduced to 25 m. It is estimated that the fires resulted in over US$ 3 billion in damage from losses in agriculture, timber, non-timber forest products, hydrological and soil conservation services, and biodiversity benefits, whilst the haze cost an additional US$ 1.4 billion, most of which was borne by Indonesians for health treatment and lost tourism revenues (Schweithelm, 1998). The objectives of this investigation were to provide more accurate estimates of the area of fire affected peatland within Central Kalimantan, encompassing near-pristine, forested peatland and degraded and drained peatland, and to quantify some of the environmental consequences of the fires. A combination of remote sensing and field checking was employed. Some of the environmental impacts of the fires are discussed and predictions made concerning the future sustainability of tropical peatland in this province.