Although classified in the order Carnivora (meat eater), the black bear actually is an omnivore, feeding on both animal and vegetable matter (Willey 1978). Because they consume an enormous variety of foods, bears fare best where there are many habitat types in a variety of successional stages. Clearcutting can contribute to this variety.
Studies regarding black bear habitat in northern Michigan, the Adirondack Mountains of New York, the Southern Appalachian Mountains in North Carolina, and the Ozark and Ouachita Mountains in Arkansas, suggest that clearcutting can be beneficial for bears by increasing new growth of plants, especially fruitproducing shrubs (Lauckhart 1956, Erickson et al. 1964, Brody and Stone 1987, Clarke et al. 1987, Brocke et al. 1988). Nevertheless, in the Interior Highlands of Arkansas, Clark et al. (1994) found that regeneration areas were used less by radio equipped bears than expected, in spite of the fact that they had a high food value index. However, abundant bear sign (e.g. tracks) was observed in the regeneration areas. Thus, it is possible that only the radio-equipped bears avoided the regeneration areas, possibly to avoid more aggressive individuals.
Analysis of bear food abundance by Costello and Sage (1994) in the Adirondack Mountains of New York indicated that even-aged, managed habitats provided the highest amounts of spring and summer foods (particularly raspberry and pin cherry), while non-managed and uneven-aged habitats provided the highest quantity of fall foods, particularly beech nuts. Habitat selection was greatly influenced by food abundance. The authors found that almost all habitats were valuable during some
time of the year, suggesting that a variety of habitats is beneficial to bears.
Other studies indicate that the removal of den trees during logging, the extension of road systems (which increases the vulnerability of bears to hunting), and large scale conversion of forest lands to other uses diminish the value of forests for resident bear populations (Cardoza 1976, MacLentz et al. 1980, Johnson and Pelton 1981, Brody and Stone 1987, Brocke et al. 1988). Although hunting and human access can and should be regulated, it is an issue independent from silviculture.
The American marten, generally assumed to be associated with mature forests, has large spatial requirements because of its trophic status. However, little is known about the influence of forest management activities on marten populations in the eastern United States. A study by Chapin et al. (1995) of marten in northern Maine compared spatial characteristics of residual forest patches and their use by marten in an industrial forest landscape characterized by extensive timber harvesting. They found that marten are not old-growth or coniferous forest obligates and that once regenerating stands reach 20 to 40 feet in height they are used by martens no differently than older stands. They recommend long-term planning to maximize residual patch area and minimize the distance between patches to increase use by marten.
Although we know of no papers regarding the effects of even-aged management on cougars, we know from the almost hemisphere-wide distribution of the species and their large spatial requirements that they occur in a wide variety of habitats. The only common denominator of these habitats is the presence of a large mammal for food. White-tailed deer appear to be a favorite food of cougars in the eastern United States. Because the majority of papers report that clearcutting enhances deer habitat, we conclude that clearcutting also can be used to improve habitat for cougars.
A review of field studies by Koehler and Brittell (1990) of lynx and snowshoe hares in north-central Washington indicated that prescribed fires, logging (clearcutting) and timber thinning created young stands needed as habitat for the cat’s prey, snowshoe hares. However, adjacent mature forest stands must be maintained as habitat for denning.Next page...Effects of Clearcutting on Tree Squirrels