A new indicator of forest fire risk for Indonesia based on peat soil reflectance spectra measurements

Conventional fire risk prediction using vegetation indexes is inappropriate because changes in soil moisture caused by plant drought stress have a 1 to 2 month time lag, which is too long for fire risk management. Further, soil and water indices used for traditional bare land assessments are also unsuitable because Indonesia is partially covered by peat soil, which has different reflection characteristics compared to typical agricultural and field soils. Here we describe a new index for estimating peat soil moisture using satellite remote sensing data. The method was developed using the ultra-blue band (435 to 451 nm) of the Land Remote-Sensing Satellite (Landsat 8) and is based on the moisture dependence of the reflected spectra measured directly. Our developed index showed a relatively strong correlation (<i>r</i> = 0.56 to 0.63) with real wildfire points and was a more reliable index than conventional measures used for fire risk management.