BURN SCAR MAPPING AND FIRE DAMAGE ASSESSMENT USING ERS-2 SAR IMAGES IN EAST KALIMANTAN, INDONESIA

Abstract

Burn scar identification and fire damage assessment was done using ERS-2 SAR radar images in East Kalimantan, an Indonesian province severely affected by wildfires during a drought period in 1997/1998. A total of 46 ERS-2 SAR Precision Images were used to map the total burned area in the province. Effects of fire on radar backscatter were investigated in test areas representing different degrees of fire damage that were visited during ground and air surveys. The degree of accuracy of burn scar and fire damage mapping was assessed using random samples of geocoded photographs and videotapes recorded during five air surveys and block forest inventories in one damaged forest area. Changes in Radar backscatter induced by fire proved to be strong. In images acquired during the drought period, a decrease of 2-4 dB was observed in burned areas. Under dry conditions of three fire damage classes could be discriminated by different types and degrees of change to radar reflectivity and image texture. The total fire-affected area was 5.2 Mio. ha. Mapping accuracy was assessed to be higher than 90 percent for burn-scar identification, while the accuracy of discrimination of different damage classes was less than 70 percent. Ground and aerial evidence suggest that the marked decrease in backscatter can be attributed to the removal of the vegetation cover and subsequently higher contribution of backscatter from dry soil. The high mapping accuracy for burn scars allows assessment of fire affected areas using standard ERS-2 satellite imagery to become operational. KURZFASSUNG