Forest Reburns Are Integral to Southern Europe's Disturbance Regimes

ABSTRACT Aim Fire disturbances are integral to fire‐prone landscapes of southern Europe. While evidence of changing fire frequency has been documented, the dynamics of forest reburns—defined as previously burned areas that ignite again within intervals shorter than the historical range with which forests ecologically evolved—remain largely unexplored. Here, we aim to provide the first large‐scale characterisation of reburns in southern Europe. Location Europe. Time Period 1985–2023. Methods Using a novel remote sensing dataset on fire disturbances, we identified areas burning multiple times by aggregating the annual information on fire disturbances. We calculated the proportion of forest area affected by fire (burn fraction) and the proportion that reburned (reburn fraction) across space and time to characterise the spatiotemporal patterns of reburn occurrence. Results We quantified the spatial extent and frequency of reburns, revealing that 30.1% of burned area in southern Europe experienced multiple fire events within the 1985–2023 period (4.24 Mha), with 84.5% of these reburns occurring within a 20‐year interval, and thus approaching the lower limit of reproductive maturity for many tree species. Reburn hotspots emerged across the Mediterranean, where 19%–21.1% year −1 of all fires were reburns within 20 years, and in the temperate forests of western Europe, where reburns accounted for 40.8% year −1 . We further show that, although the overall burned area decreased, reburns continued to account for a substantial share of annual burn activity since 2005, with even slight increases in eastern regions. Main Conclusions Our results highlight that reburns are integral to southern Europe's disturbance regimes, and we emphasise the critical role of long time series for understanding forest dynamics. Based on our results, we suggest that reburns may increasingly shape fire regimes in southern Europe under intensifying forest fire activity, which may undermine post‐fire recovery and require special consideration from management.