What is a Healthy Forest?
A healthy forest is not necessarily free of insects and diseases. The insects that eat the foliage from trees also provide food for many birds species. Some of the fungi that cause root rot in trees also convert stumps into organic matter that provides fertilizer to young trees. The brush species that interfere with young trees also provide food and shelter for birds and other wildlife.
The health of a forest stand depends on the point of view or (in formal terms) the management goals of the owner. The following example will explain what we mean by a healthy forest:
A 90 year-old 100-acre woodlot of black oak, white oak and hickory in the Central Sands contains occasional dead and dying oaks, many trees with cavities and dead limbs, occasional large white oaks with spreading crowns, a few large white pines that rise above the oak canopy and a 5-acre oak wilt pocket. The young trees growing up through the canopy are mostly white pine and a few red maples. No harvest or thinnings have been done in the last 50 years.
If the management goal is to grow and harvest high-quality oak sawlogs now and in the future, this is a very unhealthy forest; most of the larger oaks are crooked, limby or hollow and there is little or no oak reproduction (baby trees).
If the management goal is to provide wildlife habitat for the next 5 years, this is a healthy forest. The oaks provide abundant acorns for many wildlife species and many cavities for shelter. The oaks support an abundant supply of leaf feeding insects (including gypsy moth) that provide food for many birds. The dead and dying oaks provide abundant food for woodpeckers. The oak wilt pocket is filling in with young oak, white pine and mixed brush which increases the age and species diversity of the woodlot. Many deer trails and several permanent hunting stands attest to the value of the woodlot for hunting.
This is also a very interesting and pleasant woodlot to view in all seasons because of the varying colors of oaks during the growing season and the presence of large and small white pines and the occasional dead tree.
Problem: The owner expects to use the woodlot for turkey and deer hunting for the foreseeable future and pass it on to his children who expect to use it for hunting as it is used now. He is unaware that a major change in his woodlot has already started that will greatly reduce the quality of wildlife habitat within 20 years. Gypsy moth defoliation and drought will start a chain reaction that will end with the death of most of the old oaks. In 20 years, a few, remnant white oaks will remain along with a few large white pine. A thicket of white pine and red maple saplings will be growing amid the trunks of the dead oaks. The acorn crop will be greatly reduced as will the quality of hunting and the visual beauty.
What can the landowner do? First, he needs to recognize the 2 indicators that a major change is underway:
- the old age and poor health of the dominant oaks
- the lack of oak reproduction
Once the landowner recognizes these signs, he can decide what, if any, action to take. One option is to let the change occur and accept a long-term reduction in hunting quality of the land. A second option is to conduct a thinning to remove the young red maple and some of the oaks. This will allow the healthier trees more sunlight (which will help them produce an acorn crop) and allow a young oak forest to grow. The best way for the landowner to make this decision is to enlist the help of a professional forester.
A forest is always changing. Landowners need to be aware of the changes occurring in their forest in order to help it meet their immediate and long term goals by recognizing the beginnings of change and making change work for them.
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