Peatlands, ecosystems with deep (>40 cm) organic soils, play diverging roles in landscape wildfire regimes based on their moisture status. When peatlands are wet, they can limit fire spread, but when dry, they can be the source of high-severity fire and impacts including carbon loss and smoke production. The daily Peat Moisture Code (PMC) presented here calculates the change in storage in the peatland water balance by accounting for precipitation, evapotranspiration, surface/groundwater inputs, and accounts for peatland ecohydrological feedbacks by integrating peat hydrophysical properties. The output of the PMC represents the moisture level of peatland fuels, where high PMC values indicate deep water table position and dry fuel conditions, driving higher fire danger and likelihood of high-severity burns. Fire danger thresholds are presented for the example shown to assist with the interpretation of the PMC. The daily and hourly PMC will continue to be developed to more accurately estimate peatland fire danger in varying ecoregions and peatland types while maintaining the following specifications:
· Water balance model with bookkeeping approach
· Minimal data requirements consistent with federal and provincial weather stations
· Daily PMC represents the methodological basis for the hourly PMC of the next-generation Canadian Forest Fire Danger Rating System
