Management of forest fires to maximize carbon sequestration in the boreal forest of North America

The goal of this research is to understand the potential role of forest fire management in promoting carbon sequestration in the boreal forest of North America. Biomass burning has increased by 50 percent since 1850. Since 1977, the annual extent of burning in the northern temperate and boreal forests has increased six- to nine-fold. It is believed that the North American boreal forest has become a net carbon source. Given the large amount of carbon stored in boreal forests, increasing attention is being focused on their role in mitigating climate change and the role of forest fire management. This study examines two strata of the North American boreal forest previously studied by Botkin and Simpson (1990) and Simpson et al. (1993). Their studies provided the first statistically valid estimates of actual and potential aboveground biomass storage for the region. Using original plot data from these past studies, the current analysis uses a modified version of the JABOWA-II forest growth model to determine which fire regime(s) yield the maximum carbon sequestration in an ecosystem where fire disturbance is a natural component. Three scenario categories are examined: fire suppression, wildfires, and prescribed burning. 220 subplots were modeled using 50 replicates for each scenario. Using statistically valid plot data as input, the model produced statistically valid model forecasts. Results highlight the major role played by mortmass as a carbon sink in the boreal forest. Mortmass increased dramatically in virtually all scenarios modeled. Using three different measures of carbon storage achievement, both strata demonstrated substantial carbon sequestration potential over the 200-year simulation, equivalent to twice the amount of carbon on the ground in 1988. Results strongly support a management strategy that maintains the natural occurrence of wildfires in the boreal forest, even if such fires are highly destructive. Results warn that any other practice would significantly decrease carbon sequestration. Results were robust, consistent for all three carbon storage indices, both strata, and over a broad range of wildfire return rates. There is concern that policy guiding forestry-based offset projects is based on outdated, inappropriate assumptions about forests. These concerns are underscored by the results of this research.