Aspen forest duff moisture depletion and ground fire potential

Elk Island National Park (EINP) has maintained a robust prescribed fire program, but ground fire risk may limit its use. The Fire Weather Index System is the nationally recognized means of assessing moisture. The Duff Moisture Code (DMC) and the Drought Code (DC) report moisture in the shallow and deep duff layers, but have not been evaluated for the aspen forest. This study developed and validated DMC and DC relationships and quantified duff ignition within aspen stands of EINP. The role of soil bulk density and inorganic content were also evaluated. Moisture relationships and ignition thresholds at various DMC and DC were established. The DMC, as modelled from summer moisture under leaf-on conditions, appears suitable as a conservative tool for assessing fire risk. This research may also form the basis for new moisture codes for the D-1 aspen fuel type, improving prediction of ground fire occurrence.