A fire probability model for forest stands in Catalonia (north-east Spain)

The study presents a model for the probability of fire occurrence in forest stands of Catalonia. It was developed based on data from the Second Spanish National Forest Inventory (II IFN) and perimeters of the forest fires that occurred in Catalonia during a 12-year period that followed the II IFN measurement. The model was developed for forest planning, which means that the probability of fire was predicted from variables that are known in forest planning calculations. The model is suitable for both even-aged and uneven-aged stands, as well as pure and mixed stands. The variables included in the model represented easily measurable forest characteristics like elevation, tree size, stand structure and species composition. According to the model, the probability of a forest stand to become affected by forest fire increased with: lower altitudes, smaller diameters, larger basal areas, higher proportion of coniferous species and increasing variation in tree diameter. Although fire occurrence is a highly stochastic phenomenon, the model and all its parameters were significant, and the test results were consistent. The presented model can be used in stand and forest level optimizations that consider the effect of fire risk on optimal management.