By Mark Banker, Ruffed Grouse Society Senior Biologist

Since forests and shrublands dominate the more rural parts of Pennsylvania, most terrestrial wildlife is associated with trees and shrubs in one way or another.  In order to maintain healthy populations of the entire array of forest wildlife species, we need to make sure we have diverse forests, both young and old, pine and hardwood.  Working together, foresters and wildlife biologists can develop forest management prescriptions that will provide habitat for many kinds of wildlife for a long time.  While wildlife biologists tend to track habitat and population trends to prioritize habitat management and make recommendations, foresters are experts at manipulating the forest to achieve a desired mix of age classes and forest structure components that are known to be important for wildlife and forest health.

The importance of active forest management in Pennsylvania, versus passive management, or doing nothing, is well illustrated by looking at changes in forest age structure and wildlife populations over time.  In 1955, about 22% of Pennsylvania’s forests were less than 20 years-old.  This was a pretty fair balance of young forest habitat versus older forests, perfect for the ruffed grouse, American woodcock, golden-winged warbler, eastern towhee, white-tailed deer and others.  By 1989, this number had dwindled to 15% seedling/sapling as man-made forest disturbance slowed, and as of 2004 the number stood at 10% (USDA Forest Service 2004).   Mature forests dominate, which has led to some interesting and troubling trends in wildlife populations. 

Songbirds, for example, can tell us quite a bit.  Songbirds are well distributed across the landscape, there are many different species and multiple species occupy practically every identifiable terrestrial habitat.  Changes in their numbers are often a good indication of the status of a given habitat type.  From 1966 to 2006 (the period roughly overlapping the forest trends described above), 45% of songbirds that nest in scrub-shrub habitat (young forests 0-20 years-old) in PA showed statistically significant declines while 18% increased, according to the North American Breeding Bird Survey.  This is a huge decline by any standard and one that should bother us wildlife biologists a great deal.  During the same time span, 23% of songbirds that use mature forests declined while 44% increased, almost the reverse trend, as would be expected.  Since 1980, the decline in young forest songbirds has slowed as the availability of habitat has been relatively more stable in recent years.

Since 1968, American woodcock populations have declined at a rate of 3.4% per year in Pennsylvania.  This is approximately 1.5 times the regional decline.  While not increasing in the past 10 years, woodcock populations have been stable, which is an excellent sign.  Pennsylvania does not do any ruffed grouse drumming counts, but grouse hunter flush surveys suggest a fluctuating populating that has trended downward for some time.  Still, where there is extensive habitat, grouse numbers can be impressive.

On the mammal side, the bobcat and snowshoe hare (hanging on by a claw in northern PA) rely on dense young forests for prey and cover, and species like the black bear, little brown bat, deer and turkey utilize a diversity of forest stages, from very young to mature, for food and cover depending on the time of year.  Early successional forest is great habitat for deer.  It stands to reason that the overall maturation of PA forests leading to a dramatic decline in deer habitat quality has contributed to the degradation of our mature forest understories and our inability to regenerate new, young forests that are good deer habitat.  Fortunately, this is a problem that is being addressed so that habitat quality can be improved via timber harvest.

It seems clear that active forestry is the key to maintaining a balance of habitat types and slowing or reversing the decline of some species and insuring the continued abundance of others.  A variety of management techniques that improve the structure of mature forests and create new, young forests will have to be used in unison. We must also recognize that there is value in leaving an appropriate amount of forest unmanaged as a frame of reference.  Public forest managers have a responsibility to provide diverse habitat for wildlife and for the enjoyment of all citizens and to set an example for private forest owners, who own most of the land and who play an important role in wildlife management.  There is much work to be done in PA, as in many eastern states, to secure the future of forest wildlife.  The Society’s experience in PA tells us that there are plenty of talented foresters and biologists who are working together to make it happen.

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