In the last decades, wildfire hazards have increased to dangerous levels, becoming the focus of debate among policymakers both at the local and national levels. This paper proposes a Spatio-temporal approach to study the determinants of fire size distributions taking Sardinia as a case study in the time span 1998-2009. Special attention is devoted to socioeconomic factors of local communities where wildfires occurred. The main finding of this study is that the proportion of public lands in a given municipality tends to mitigate the extent of the burned area. In addition, communities with a higher percentage of people employed in the primary sector are less likely to experience large burned extents.