Implications of Peat Burn Severity on C Emissions and Post-Fire Successional Trajectories in Boreal Northwest Territories Canada

Boreal Peatlands, which store most of their carbon belowground, cover more than 75% of southern Northwest Territories Canada and the effects of wildfire in these systems is largely understudied. Under funding from NASA's Arctic and Boreal Vulnerability Experiment, research has been conducted over the past three years to understand the effects of widespread wildfire on peatlands and uplands that traverse the taiga shield and taiga plains ecozones and gradients of ecosystem types, severity of burn and seasons of fire. Field observations collected in 2015-2018 are being linked to remote sensing to scale our field based observations to the landscape scale. The depth of peat consumption in these wildfires has a direct effect on carbon emissions and post-fire successional trajectories. We are finding relationships in the field between peat burn severity and post-fire conifer tree recruitment and relationships to broadleaf recruitment are under study. Landsat-8 algorithms have been developed to scale the field data on belowground consumption or peat burn severity to the landscape scale, and thus map peat burn severity across the region. In addition, multi-temporal, multi-sensor pre-burn radar and optical imagery was used to map peatland types and distribution across the study area. The intersection of these maps is allowing us to understand the patterns and controls of burn severity in peatlands across the ecological zones and also to predict where we expect conifer vs. broadleaf succession based on the field-derived correlations between peat burn severity and post-fire succession. Recent changes in climate including earlier springs, longer summers and changes in moisture patterns across the landscape, are affecting wildfire regimes of the Arctic-boreal region including intensity, severity and frequency of wildfires. By studying a range of sites stratified across the gradients of biotic and abiotic factors we are increasing our understanding of the vulnerability of peatland ecosystems to wildfire, fire behavior, C consumption/emissions and the trajectories of succession that are likely to ensue.