Pre-fire forest type as an integrated indicator of long-term post-fire aboveground biomass recovery in boreal forests

Abstract

As the largest terrestrial biome, boreal forests play a critical role in the global carbon cycle, support diverse wildlife habitats, and sustain timber production, while wildfires represent a major natural disturbance shaping their function. Understanding post-fire aboveground biomass (AGB) recovery is essential for predicting long-term ecosystem functions. In this study, we tracked post-fire AGB trajectories over a 71-year period for 332 fire events in Wood Buffalo National Park, Canada. We evaluated AGB recovery across four pre-fire forest types dominated by black spruce, jack pine, white spruce, and deciduous tree species. Our results suggest substantial variation in post-fire AGB recovery rates, with the fastest AGB accumulation observed in forests dominated by deciduous species (57 gC/m2/yr), followed by white spruce (39 gC/m2/yr) and jack pine (36 gC/m2/yr), and the slowest recovery occurring in forests dominated by black spruce (21 gC/m2/yr). These differences primarily reflect the site-productivity gradient, with pre-fire forest type serving as an integrated indicator of species composition, fire behavior, and regeneration strategy. Recognizing the distinct recovery trajectories among forest types is important for understanding long-term ecosystem functions and for assessing boreal forest resilience under increasingly frequent and severe fire regimes. Moreover, our findings suggest that pre-fire forest type serves as a practical, integrated indicator of post-fire biomass recovery rates, providing valuable insights for boreal forest fire management and ecosystem modeling.