Fishers (Martes pennanti) occur only in extensive, continuous northern forests and appear to prefer dense, lowland and spruce-fir forests with high canopy closure. " p. 349

"In winter, snowshoe hares occurred exclusively in dense, lowland-conifer and alder stands, while porcupine occurred exclusively in open, upland, hardwood forest." These are the fisher’s main prey source. Fishers usually hunt snowshoe hares by zigzagging through their more dense habitat, while going straight to porcupine dens, reducing the time spent in those more open habitats. P. 350