The Canadian fire weather index system and wildfire activity in the Karst forest management area, Slovenia

The Canadian fire weather index system (CFFWIS) has been adopted for fire danger rating throughout Europe as part of the European Forest Fire Information System. However, its performance has not been thoroughly assessed, especially in environments less prone to fire. In this study, we characterised fire activity between 1995 and 2009 in the sub-Mediterranean Karst forest management area of SW Slovenia. Five fire danger classes (very low, low, moderate, high and very high) were derived from percentile analysis of the CFFWIS Fire Weather Index. These classes were found to be related with fire activity descriptors. Logistic regression prediction of fire-days based on CFFWIS indices had low accuracy, and better discrimination was achieved by classification tree modelling. Fire activity was found to be driven by current weather conditions rather than by drought. Our findings highlight the potential of fire danger rating to guide fire management but also the limitations imposed by relatively low incidence of fire and the spatial scale of analysis.