Habitat for American martens (Martes americana) is associated with forest types that offer fine-scale structural complexity in part used to access the winter subnivean environment, which is used for food procurement, predator avoidance, and rest. We assessed habitat characteristics associated with points of subnivean access by martens from winter tracking in a boreal mixedwood forest in northern Ontario. We then assessed areas designated as reserved marten habitat according to Forest Management Guidelines for the Provision of Marten Habitat in Ontario with respect to these characteristics. Coarse woody debris counts were positively associated with subnivean access. We found some evidence that subnivean access points differed in a transition from patches of coniferous to mixedwood forest, defined by tree basal area. Especially in mixedwood patches, deciduous shrub density may also facilitate subnivean access. Development of guidelines to protect features associated with fine-scale structural complexity important in winter to martens should be a research priority.

Nomenclature: Flora of North America Editorial Committee, 1993; Wilson & Reeder, 1993.