Flammability and Combustibility of Two Mediterranean Species in Relation to Forest Fires in Croatia

Climatic conditions are extremely important for the start and spread of forest fires. Flammability and the spread of fire are sensitive to the interactions of variables within ecosystems, such as weather, fuel, and topography. Certain variables are highly significant for forest fires and are applied in various models, particularly the moisture content of potential fuel, and its flammability or combustibility. However, such these models cannot determine the true values of the required variables, unlike actual empirical research. Areas with the highest number of fires show significant variability and differences in air temperature, humidity, and precipitation. These factors have a strong influence on flammability, combustibility, and moisture content of Mediterranean species. This study analyses the flammability and combustibility of two Mediterranean species important for the Adriatic area in Croatia: climazonal holm oak (Quercus ilex L.) and Aleppo pine (Pinus halepensis Mill.) as an important conifer for afforestation and reforestation. The results of linear correlation coefficients of flammability of these species at the studied localities show a statistically significant and very strong correlation between flammability and the moisture content of the tested sample, with the exception of Aleppo pine on the island of Rab. The analysis of variance of combustibility showed that there were no statistically significant differences between nearly all variables tested. The results indicate the significant effect of live fuel moisture content on the flammability and combustibility of natural fuels.