Effects of dereference evapotranspiration and relative humidity on forest fire occurrences in Zagros Forests, west of Iran (Case study: Khouzestan province)

The aim of the this study was to evaluate reference evapotranspiration (ET0) and relative humidity (RH) impacts on forest fire occurrences in Zagros forests of western Iran, Khuzestan province. Monthly mean meteorological data obtained from five meteorological stations were employed for mapping the ET0 and RH. When ET0 was taken into account, 16.8 % and 21.7 % of this region were classified as high and very high risk classes, respectively while the map of RH indicated that 44.5 % of the study area was in the high risk class of forest fire. Cross-validation analysis based on ET0 revealed that the maximum number of fire occurrence per hectare were in the very low and moderate classes of fire risks. However, for RH the maximum number was observed in the very high risk class (0.003 numbers per hectare). In compare to ET0, RH is preferable for understanding the effects of forest fire occurrence as well as for the forest fire mapping.