Article #56, February 2002
By Bill Cook
What unique contributions to biodiversity does “old growth” make? What species cannot survive without the presence of “old growth”? How did those species survive after the historic logging era when our forests were considerably younger and less developed than today?
There is probably no species or landscape function that is dependent upon “old growth”. If there were, they probably would have disappeared with the days of lumber camps and river runs. And there are few, if any, North American species that have disappeared exclusively as a result of logging and none due to forest management.
The term “old growth” has both scientific and cultural sets of definitions. Most of the focus appears to be on the cultural definitions.
Many discussions about “old growth” contain little ecological or science-based reasoning. The implicit valuation of simply “how a forest looks” seems to outweigh the utilitarian values to society or ecological values across the landscape. Such a narrow vision is little different than that of the lumber baron’s view of the timber resource a hundred years ago. Both tend to favor specific interests at the expense of the whole.
“Old growth” is an inherently poor term. I doubt many folks envision skinny little bog black spruce when they envision “old growth”, even if the trees are 150 years old. They are thinking about tall forests with big trees. You might call it the “redwoods syndrome”.
Ecologically, “old growth” involves concepts such as tree age, succession, stand structure, snags, large diameter tree falls, etc. The more popular usage seems to mean “upland forests that have a lot of big trees”.
To achieve a true “old growth” condition you need to have old trees. Most of our forest area was cut and burned within the last 100 years or so. Sugar maple, beech, yellow birch, hemlock, white pine, and other “old growth species” are just young adults at a hundred years. Obviously, we’ll have to wait another hundred years before appreciable acreages of “old growth” are possible. There just hasn’t been enough time.
As our northern hardwood forest ages, more and more acreage resembles “old growth”. These trends have been documented since the 1950s. Theoretically, the pressure to set aside a “rare” ecological commodity will diminish as it becomes less and less rare.
Large diameter trees are an acceptable temporary substitute for true “old growth”. The forest may take 150 years or more to achieve such a condition without management, if it ever will. With management, it’s already beginning to happen in less than 75 years. This is an incredibly wonderful and terribly understated achievement.
Well-managed northern hardwood stands across the Lake States are the first “old growth” look-alikes to emerge from the post-logging era forest. It’s logical that these will be snapped up for “old growth” set asides. However, that’s a rather poor reward for good forest management and can be hard on communities that have invested in the high value resource.
Most old growth proponents seem ravenous for “old growth” set asides. They want it now when it’s just not yet available. It’s like trying to find maturity in a junior high school.
“Old growth” seems a growing banner for new-age or pantheist type thinkers that maintain some unnatural vision of a pristine forest. It seems to be a buzzword that opposes management of forest resources for the benefit of people. It’s a weapon applied against science-based use of an incredibly rich resource.
It’s no wonder that many folks in the forest management community chafe under “old growth” initiatives. The term has come to mean things that it should not.
Does “old growth” have value based in the ecological sciences? Yes. There are combinations of forest system components that were once more common. Ecological processes operate somewhat differently in “old growth” forests. Species abundance and richness differ. These differences can advance our understanding of forest ecology, which might improve management. But these values don’t really have much to do with the “old growth” activism that we see today. After all, these values are just science.
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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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