Decadal-Scale Recovery of Carbon Stocks After Wildfires Throughout the Boreal Forests

Boreal forests store 30% of the world's terrestrial carbon (C). Consequently, climate change mediated alterations in the boreal forest fire regime can have a significant impact on the global C budget. Here we synthesize the effects of forest fires on the stocks and recovery rates of C in boreal forests using 368 plots from 16 long-term (>= 100 year) fire chronosequences distributed throughout the boreal zone. Forest fires led to a decrease in total C stocks (excluding mineral soil) by an average of 60% (range from 80%), which was primarily a result of C stock declines in the living trees and soil organic layer. Total C stocks increased with time since fire largely following a sigmoidal shape Gompertz function, with an average asymptote of 8.1 kg C m(-2). Total C stocks accumulated at a rate of 2-60 g m(-2) yr(-1)during the first 100 years. Potential evapotranspiration (PET) was identified as a significant driver of C stocks and their post-fire recovery, likely because it integrates temperature, radiation, and the length of the growing season. If the fire return interval shortens to <= 100 years in the future, our findings indicate that many boreal forests will be prevented from reaching their full C storage potential. However, our results also suggest that climate warming-induced increases in PET may speed up the post-fire recovery of C stocks.