Effects of Peat Development and Wildfire on Permafrost Peatland Carbon Stocks in the Northwest Territories, Canada

Permafrost responses to wildfire range from rapid recovery to irreversible thaw with large consequences for ecosystem function and carbon cycling. This study used a chronosequence of permafrost peat plateau sites in Northwest Territories, Canada that vary in time-following-fire to ask questions about active layer and organic carbon stock recovery during post-fire succession. Radiocarbon dating of basal peat layers showed the sites varied in the timing of peat initiation from 2416 - 8619 cal yr BP. Cumulative organic carbon stocks increased with peatland initiation age and peat thickness, with older peatlands experiencing more recent fire activity. Overall results show that permafrost plateau organic carbon stocks were driven more by variation in peat initiation than time-following-last fire and that, at least for top-down active layer thickening, carbon stocks can be resistant to fire. We suggest direct or indirect measurement of peat initiation age may be useful information for fire managers.