Theme 1. Managing Smoke

Posters on Managing Smoke

The Coincidence of Land and Forest Fire and Peat Distribution in Indonesia: An Approach for Preventive Measures

by Muhamad Rahman Djuwansah¹ and Muchlisin Arief²

Land and Forest Fire (LFF) usually happen since long time ago in Indonesia. Within traditional Shifting Cultivation agricultural system of indigenous people, forest or bush "slash and burn" is periodically practiced for land preparation at the end of dry season. Nowadays, not only the indigenous farmer that perform slash & burn, but also the transmigrants who do not master to control the fire of forest burning, and the enterprises who normally perform large scale land clearing simultaneously for converting the forest into plantation. The extension and quantity of LFF is getting more and more important with the increasing economic activity, particularly related with forest conversion, because land clearing cost by burning is low compared to that by cutting down the trees. Since the forest burning is not managing properly, the accumulation of these burning often become a big disaster. The events of devastated LFF, such as happened at 1994 and 1997, in fact, coincide with the year of severe dry season related to ENSO phenomenon.

Daily monitoring of LFF in Indonesia is performed since 1996 by National Institute for Aviation and Aerospace (LAPAN). Hot spots of Land or Forest Fire is recognized from satellite as the pixels that possess average soil surface temperature over 49°C filtered from thermal band image of NOAA or LANDSAT-TM. Most of hot spots in Sumatera and Kalimantan. The number of hot spots increase from April and reach the maximum at the end of September. Geographically, the majority of hot spots is found on peat-land or organic-rich soils, mainly for the fires at August-September. The extension of peat deposit in Indonesia covering about 27 million hectares, spread out mainly in the lowland of eastern coastal Sumatera and Kalimantan. Naturally, peat land is found as inundated bog and covered densely by tropical forest. At the end of September, water content of peat is the minimum, and peat become easily burnt. In fact, peat is an excellent combustible, especially when the humidity is very low (par ex: some industrial estate use peat with 20 % humidity for their fuel). The humidity of peat or soil-organic matter will decrease with water table lowering, such as by drainage, or with increasing evaporation such as when vegetation cover was removed. Under dry condition, the fire will be difficult to be controlled. Therefore, peat, peaty soils and organic rich soil provinces should be considered as the vulnerable area for wild fire.

Dealing with LFF problems, preventive measure posses many advantages than that of curative. Since triggering conditions of wildfire depend much on climate and soil organic matter, an alert system of LFF could developed based on micro climatic parameters. Early warning of LFF could be obtained by monitoring of soil and air humidity and water table at vulnerable area. When their value is reaching the critical level, the alert status could be announced for the surrounding inhabitants. Considering that wildfire require immediate handling, the system will effectively operate if the responsible institution for the alert status announcement and wild fire suppression should be held by local level organization: District or sub district.

Footnote_______________

¹ R&D Centre for Geotechnology, Indonesian Institute of Sciences (LIPI), Indonesia

² National Institute of Aviation and Aerospace