Surface fire spread potential in trembling aspen during summer in the Boreal Forest Region of Canada

In Canada, the importance of seasonality in forest fire danger rating associated with phenological changes in deciduous tree leaves and lesser ground vegetation has historically been taken into account by dividing the fire season into three distinct periods (i.e., spring, summer, and fall). During the mid-1980s, the developers of the Canadian Forest Fire Behavior Prediction (FBP) System did not envision that the M-2 Boreal Mixedwood – Green fuel type with 100% hardwood composition would eventually be explicitly interpreted by field users and other researchers to represent a trembling aspen (Populus tremuloides Michx.) fuel type in the summer following green-up or flushing of the overstory canopy and understory vegetation. Interest in what has become to be known as the D-2 FBP System fuel type to represent leafed-out trembling aspen stands during the summer fire season has steadily increased since. Formal recognition of such a fuel type may very well constitute an example of overextending the original basi...