Fuel moisture content dynamics under climate change in Spanish forests.

Monitoring live and dead fuels moisture content (LFMC and DFMC) dynamics plays a crucial role in wildfire management and prevention actions. In this study we estimate LFMC and DFMC across the 21^st century, considering the meteorological conditions derived from medium and high greenhouse gas emission scenarios (RCP 4.5 and 8.5) by selecting a representative subset of global and regional climate models combination. A stable atmospheric CO₂ concentration was also considered to assess possible CO₂ mitigation effects. We applied semi-mechanistic models to infer moisture content dynamics across 36 study sites located in peninsular Spain, which corresponds with monospecific stands of twelve tree species. Overall, our results indicate that both, live and dead fuels moisture content dynamics, are going to experience generalized declining trends in the coming decades. Furthermore, increases in the number of days per year when fuels moisture content falls below wildfire occurrence thresholds is going to extend fire seasons lengths. Besides we observe a significative CO₂ mitigation effect, is not enough to offset LFMC declining trends induced by climate change. Finally, results suggest that, in ecosystems where plant biomass is abundant enough to sustain a fire, moisture content of live fuels is going to be the main limiting factor for future large wildfire occurrence.