Global analysis of fire regimes: Burnt area and fire intensity

Delineating global fire zones and analyzing their variations in different vegetation types areimportant to understand the climate-vegetation-fire coupling, and could serve as a reference to policy makers. However, few studies have investigated the two prominent fire characteristics (burnt area and fire intensity) together, and their variations in different vegetation types. As a first step to exploring these two fire characteristics as a whole, we presented a flexible classification of global fire zones based on metrics of burnt area and fire radiative power derived from satellite data. The distribution of the fire zones in different vegetation types and their relationships with the variables on climate, ignition, and anthropogenic activity were analyzed further. We found that fire zone of both largeburnt area and high fire intensity coincidedmainly with low anthropogenic activities (population density < 20 people km-2).In contrast, fire zone of both smallburnt area and low fire intensity showeda clear tendency to high population density (> 90 people km-2). Additionally, the distribution of fire zones greatly varied with vegetation types, but this was presumably attributed to different causes. Insights from this study could have important implications for biodiversity conservation and be used to direct fire management efforts, given the important roles of burnt area and fire intensity in fire regime studies. Although only two dimensions of fire regimes were considered in this study, the framework of our analysis could be generalized to integrate more indicators of fire regimes at large scales.