Forest reburns are integral to southern Europe’s disturbance regimes

Fires disturbances are integral to fire-prone landscapes of southern Europe. While evidence of changing fire frequency has been well documented in Europe, the dynamics of forest reburns - defined as previously burned areas that ignite again within intervals shorter than the historical range - remain largely unexplored. Here, we present the first large-scale characterization of reburns in southern Europe, using a novel remote sensing dataset on fire disturbances from 1985 to 2023. 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. Extreme reburns within 10 years were also observed in 22.4%. Reburn hotspots emerged across the Mediterranean, where 19-21.1%yr ^− 1 of all fires were reburns within 20 years, and in the temperate forests of western Europe, where reburns accounted for 40.8% yr⁻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 some regions (i.e. Dinaric Mountains and Balkan region). Our results highlight that reburns are integral to southern Europe’s disturbance regimes, and we emphasize 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 requires special consideration from management.