Global Drivers of Post-Fire Ecosystem Recovery: Insights from Solar-Induced Chlorophyll Fluorescence

The recovery time of ecosystems following wildfire significantly influences carbon sequestration rates, land-atmosphere exchanges, and hydrological processes. Post-fire recovery has been studied at local scales but there is a lack of comprehensive global-scale analyses. We used solar-induced chlorophyll fluorescence (SIF) to quantify the recovery of photosynthetic activity after more than 10,000 fires from diverse ecosystems. We used the relaxed lasso technique to identify key determinants of the length of time required for post-fire recovery, and used these to build a linear regression model. Our results show that vegetation characteristics, fire properties, and post-fire climatic conditions all influence recovery time. Gross primary production (GPP) is the most important determinant of recovery time: ecosystems with higher GPP recover faster. Fires with greater intensity and duration, which cause more extensive vegetation damage, are associated with longer recovery times. Post-fire climate also affects recovery time: anomalously high temperatures and temperature seasonality, and increased number of dry days, cause slower recovery, while above-average precipitation accelerates recovery. Recovery times vary between different biomes, potentially reflecting variations in plant fire adaptations: ecosystems with a higher abundance of resprouting plants recover more rapidly. These findings provide a global perspective on how vegetation responds to fire disturbances, offering insights into carbon and water cycle dynamics under changing climatic conditions.