Peat surface compression reduces smouldering fire potential as a novel fuel treatment for boreal peatlands

The wildfire regime in Canada's boreal region is changing; extended fire seasons are characterized by more frequent large fires (>= 200 ha) burning greater areas of land, whilst climate-mediated drying is increasing the vulnerability of peatlands to deep burning. Proactive management strategies, such as fuel modification treatments, are necessary to reduce fire danger at the wildland-human interface (WHI). Novel approaches to fuel management are especially needed in peatlands where deep smouldering combustion is a challenge to suppression efforts and releases harmful emissions. Here, we integrate surface compression within conventional stand treatments to examine the potential for reducing smouldering of near-surface moss and peat. A linear model (adj. R-2 = 0.62, p = 2.2e(-16)) revealed that ground cover (F-[2,F-101] = 60.97, p < 0.001) and compression (F-[1,F-101] = 56.46, p < 0.001) had the greatest effects on smouldering potential, while stand treatment did not have a significant effect (F-[3,F-101] = 0.44, p = 0.727). On average, compressed Sphagnum and feather moss plots showed 57.1% and 58.7% lower smouldering potential, respectively, when compared to uncompressed analogs. While practical evaluation is warranted to better understand the evolving effectiveness of this strategy, these findings demonstrate that a compression treatment can be successfully incorporated within both managed and unmanaged peatlands to reduce fire danger at the WHI.