Two decades of fires in the Brazilian Amazon and the differences in patterns between open and forest vegetation

Abstract. This study investigated the pattern distribution of fires in the Brazilian Amazon and their relationship with deforested areas from 2003 to 2022. The primary objective was to analyze fire spots’ spatial and temporal variation. First, we examine whether open vegetation (non-forest areas) in the Amazon exhibit a higher density of fire spots than forested areas. Second, we analyze how the density of fire spots in deforested areas varies with the time elapsed since deforestation. Using recent fire monitoring data and satellite imagery, the study employed statistical techniques to reveal significant patterns and trends. Our findings indicate that fire spot density is associated with deforestation in forested lands; however, this relationship does not hold for non-forest ecosystems. Fire spots are more frequent in years with higher deforestation rates, exhibiting similar trends in both forested and non-forested areas. Nevertheless, fire spot density is generally higher in originally forested lands subjected to anthropogenic activities compared to non-forest areas experiencing similar disturbances. In contrast, fires are more common in non-forest ecosystems with minimal or no disturbance compared to forested areas. Additionally, we observe variations in fire spot density over time in deforested areas, with higher densities occurring in the year the forest was cleared. In non-forest vegetation, the frequency of fires is similar in natural and anthropized areas, but both are lower compared to areas where vegetation has been recently suppressed. This study enhances our understanding of the environmental impacts of deforestation and provides valuable insights for formulating management and conservation policies in the Amazon.