Summer 2002 Volume II, Number 2
FOREST MANAGEMENT AND THE CONSERVATION OF FOREST WILDLIFE
By Mark Banker, Regional Biologist, Ruffed Grouse Society
Each species of forest wildlife has a particular type of habitat that it prefers. Some species, such as the pileated woodpecker, prefer mature forests. The large-diameter
trees of mature forests provide sites for nest cavities, as well as potential sources of food in the form of wood-boring insects that often infest dead and dying old trees. Other species, like the golden-winged warbler, prefer very young forests. The thick protective cover afforded by literally thousands of small-diameter trees and shrubs growing closely together hides nests and recently fledged young from potential predators. In addition, the lush vegetation of young forests supports many insects, an important food source for developing young birds.
Temporary openings and thick young forests are important habitats for ruffed grouse, white-tailed deer, black bear, wild turkey, and many species of non game wildlife as well, including the eastern towhee, yellow-breasted chat, field sparrow, and many others. Breeding bird Survey data document that whereas 50% of the bird species that breed in young forest habitats are declining in the eastern United States, only 24% of the bird species that breed in mature forests are declining. Conversely, only 19% of the birds of young forests are increasing, whereas 39% of the birds of mature forests are increasing. These data do not suggest that we ignore the documented conservation needs of some species that prefer mature forests. However, these data clearly demonstrate the importance of placing additional emphasis on the conservation of wildlife that require young forest habitats.
Currently, the forests of the eastern United States are pre-dominantly middle aged as a result of past land use. Few very old forests exist east of the Great Plains and young forest habitats are becoming increasingly rare throughout many regions of the east.
Historically, our eastern deciduous forest landscape was a patchwork of various types and ages of forest - maple, aspen, oak, very young to very old. Patches of young forest were created by fires, windstorms, insects and diseases, and other types of disturbance. Patches of old forest developed where disturbance had been absent for many years, allowing the trees to mature, die, and be replaced by young trees already growing beneath the forest canopy, waiting for their turn to shine in the sun. Today, because society has virtually halted fire from playing its ecological role in the renewal of our eastern forests, forest management practices are the primary means of sustaining important young forest habitats and associated wildlife. Breeding bird Survey data document that whereas 50% of the bird species that breed in young forest habitats are declining in the eastern United States, only 24% of the bird species that breed in mature forests are declining.
Forest management practices and the resulting young forest habitats are currently relatively common in northern Minnesota, Northern Maine, and the pine forests of the southeast. This is due to a combination of ecological and economic factors. The old forests of these regions are susceptible to forest pests that can kill old trees. Therefore, many old forest stands have been managed, through logging, to harvest wood fiber prior to its decay, and to regenerate healthy new forests. In addition, forest products industries are important to the economy of these regions.
Forest management practices called even-age" remove all or most of the mature trees from the treated stand at one time, creating thick young forest habitats free to grow in full sunlight. These practices typically lead to the establishment of a forest where all of the trees are the same (even) age. Uneven-age forest management practices remove a single tree here and there throughout the stand and maintain substantial shade. These practices create a forest that supports trees of many (uneven) ages, but one that is far more open than the thick forests established through even-age management.
Oak forest communities dominate much of the forest landscape of the eastern United States yet are declining in most regions. Although acorn production can vary widely year-to- year, this food source is critical to many species of forest wildlife. Even-age forest management practices are generally required to sustain oak forests, as young oak trees require substantial sunlight or they will wither and die. Like oak, the aspen forests of the Great Lakes region are sun loving. A clear-cut regeneration-treatment is the optimum method to harvest a mature stand of aspen and to make way for a vigorous young aspen forest.
Unfortunately, because even-age forest management practices are visually dramatic, they can engender opposition from some within the public that don't fully understand the reasons for their use. Resource management agencies have responded to this opposition by reducing the use of even-age forest management on National Forests and other public forestlands. Reductions in the use of even-age management mean that fewer and fewer acres of temporary openings and young forest habitats are available on public lands. In addition, forest management as typically practiced on private forestlands maintains too many mature overstory trees for these habitats to develop.
As deciduous forests in the east continue to mature, they will increase in volume and in potential value. This could lead to increased proactive forest management and, therefore, increased young forest habitat. However, private forestland owners control most of the forestland in the east (70%) and these owners typically do not consider economic benefit from the sale of forest products as an important reason for forest ownership. Therefore, proactive management and the establishment of temporary openings and thick young forest habitats will probably not significantly increase on these lands. The bottom line is that the ongoing declines of many species of wildlife that depend on young forest habitats are likely to continue unless we increase the amount of habitat for these important components of biological diversity, by increasing the amount of even-age management practiced on our forest landscapes.