Article #55, January 2002
By Bill Cook
Most of us realize that our forests have a wide range of species, from bugs to birches. The Upper Peninsula harbors about 450 species of vertebrate wildlife, those with backbones, and 70-80 species of trees.
All species have habitat requirements. Most of our U.P. is covered by a forest of one sort or another. These forests consist largely of “early successional species” and “later successional species”. This ecological concept of “succession” has to do with the predictable changes of species associations over time.
Forests are always changing in a number of ways.
For the most part, trees early in succession require lots of sunlight to grow, such as aspen, paper birch, and jack pine. Later successional tree species, such as sugar maple, basswood, and cedar, tend to have the ability to reproduce in their own shade. The concept of succession profoundly impacts forest management strategies.
One controversial issue with the regeneration of early successional forests revolves around clearcutting. This harvest method has severe visual impacts which usually overshadow the ecological strategies in the public arena. Too often, we forget that this is, essentially, how these forest types maintain themselves in nature. The critical role of disturbance in forest ecology is rarely factored into public opinion.
In defense of clearcutting, it provides the kind of biological conditions that early successional tree species need to regenerate. Wind, fire, floods, insects, and diseases are nature’s way of “clearcutting”. Clearcutting does not exactly mimic these natural disturbance patterns, but it comes pretty darn close. Some forest ecologists are now saying our clearcuts should be larger, if we want to more closely resemble nature. Finally, the ecological benefits are much longer-lasting than the negative visual effects.
Management allows us a choice in the “when” and “where” of forest regeneration, rather than the apparent randomness of nature.
You might ask about the value of early successional forests. Most of our game species depend heavily upon them. Entire industries are based on the timber products from these forests. These forests capture more greenhouse gases than later successional forests, although age is a more important factor. They add diversity to the landscape, like all forest types.
Most of our endangered and threatened species, and species of concern, are tied to early successional vegetation. Why? Because the forests of the Lake States have recovered and aged nearly a century since the historic logging boom. Due to a shorter lifespan, these early successional species have been dropping out of the landscape for at least a decade. Many associated wildlife species follow them down that road.
Few people would argue about the importance of maintaining early successional forest types in our landscape. This, of course, will require planning and management in order to achieve a balance that will provide the blend of forest resources needed for future generations. Nature, alone, will not provide this.
Debate about early successional forests more often focuses on “how much”.
Opponents of current levels of early successional forests often cite lower amounts at presettlement times and advocate a return to these “natural” levels. However, social and ecological conditions today are not the same as they were 200 years ago and our forests reflect this. For example, native species are increasingly threatened by invasive exotics.
Another argument against maintaining early successional forest types is that succession is disrupted. Well, of course it is. That’s the nature of early successional types. They depend upon this sort of disturbance. Allowing too much of the forest to succeed into later successional types will reduce landscape diversity and can leave the forest more vulnerable to natural disturbances, such as windstorms, insects, and diseases.
Furthermore, “presettlement” forests were only snapshots in time. They were created in conditions that no longer exist. In a very real sense, a managed forest is nearly as “natural” as those presettlement forests. Most people would be hard-pressed to see the difference.
Our northern species are not highly adapted to precise ecological conditions.
These species have been raked over the coals by glaciers, huge swings
in climate, and other dramatic changes. To survive in the north, a species
must be a generalist, capable of living within an ecological range of conditions.
The most important forest management question has to do with how we want to craft our forests for the future. Nature provides a fairly wide spectrum of scenarios within the bounds of sustainability. Foresters and other resource managers generally operate well within these natural boundaries. Social acceptance, however, frequently has a much narrower tolerance than nature.
In order to achieve a desired forest of the future, managers will need to use every tool and stratagem available, including clearcutting. A sustainable forest, which includes the people dependent upon the forest, will be compromised if we start tying the hands of resource managers due to well-intentioned but misguided public policy. Instead, let’s create and maintain policies that allow professionals to practice what they’re trained to do.
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Bill Cook is an MSU Extension forester providing educational programming for the entire Upper Peninsula. His office is located at the MSU Upper Peninsula Tree Improvement Center near Escanaba. The Center is the headquarters for three MSU Forestry properties in the U.P., with a combined area of about 8,000 acres. He can be reached at firstname.lastname@example.org or 906-786-1575.
by Bill Cook, Forester/Biologist, Michigan State University Extension, 6005
J Road, Escanaba, MI 49829
906-786-1575 (voice), 906-786-9370 (fax), e-mail: email@example.com
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