"... habitat is the main concern involving martens and the fisher (Martes pennanti), especially in the northwestern United States" (p. 318)

"Most conservation concerns presented at the symposium revolved around population-level impacts on boreal forest martens and the fisher. The boreal forest martens show consistent close associations with mesic coniferous forests that have complex physical structure, most often in old, uneven-aged stands. In winter, when they are energetically limited, sables and American martens (Buskirk et al. 1998) specialize on small bird or mammal prey and rest in sites beneath the snow, often in association with coarse woody debris. They survive winter by highly selective use of stand ages and types, preferring those with dense and complex structure near the forest floor. This structure, including living branches, logs, and other coarse woody debris, is important because it provides protection from predators, access to spaces beneath the snow where prey animals live, and protected sites where martens can minimize energetic costs while resting. Where complex physical structure is lacking, either at the scale of the stand or the landscape, boreal forest martens and fishers tend to be scarce or absent. Major retrogressional habitat change, especially cutting of temperate and boreal coniferous forests, has interfered with natural forest dynamics, especially structural and vegetational heterogeneity. Intensive wood-production programs involving short rotation times generally provide little of either." (p. 318)

"Some have characterized the fisher and American marten as among the most climax-dependent of North American mammals (see Harris 1984:61). And the habitat area requirements of both species are enormous; home ranges of the American marten and fisher are about 50 times that predicted on the basis of body size (Buskirk and McDonald 1989; Powell, in press). Thus, their huge areal requirements may make martens and fishers useful umbrella species for the protection of temperate coniferous forests; habitat loss limited to that which can be tolerated by these species should provide protection for virtually all other vertebrates." (p. 319)