Article #147, August 2009
By Bill Cook
Visual quality is a particularly poor measure of ecological integrity. However, it's a quality that is too often used to make judgments about the condition of our forests. Of course, the value of the eye of the beholder depends upon the knowledge of the beholder. And, not too many people know a lot about forest ecology.
There are cases where visual quality is low but ecological integrity is high, as well as the other way around.
In the first case, for example, take a clearcut in an aspen or jack pine stand. Usually, the visual quality is rather low during the first couple of years after such a harvest. Yet, in order to maintain these stands, a catastrophic disturbance is needed. Nature typically used things like wildfire and massive insect outbreaks. The clearcut regenerates the stand without the losses associated with a wildfire or insect outbreak and provides revenue for the landowner and products to society. That's kind of like a multi-win situation.
Without catastrophic disturbance of some sort, certain forest types will decline over time. Indeed, some forest types are doing just that.
Now, "catastrophic" does not mean bad. Such disturbance not only regenerates sun demanding trees such as aspen and jack pine, but it also provides habitat for a wide range of species, both plant and animal. These are typically different suites of species than what were there previously, but such a change, temporary as it might be, is a good thing. This is especially true if you're one of those species that thrive in very young forest stands. Just ask a harrier or a big-leafed aster.
Catastrophic disturbances, of the normal kind, do not result in any permanent decline in the quality of soil, water, or air. Temporary carbon losses from the soil are quickly returned and the resulting young forest sequesters considerably more carbon than it did prior to the disturbance. The carbon that was harvested as forest products may have a long storage life, depending upon what the forest products were manufactured into.
In the second case, a thrifty stand of northern hardwoods (sugar maple, basswood, beech, yellow birch, etc.) with an open understory presents a park-like appearance that many people would rate with high marks for visual quality. However, biologists might refer to such a forest stand as an ecological desert. Without an active understory, an entire range of species is missing, leaving a lack of biodiversity and dysfunctional ecological dynamics. Northern hardwoods are supposed to have an understory of tree regeneration, shrubs, spring wildflowers, and the animals associated with such a stand structure.
Oddly, a red pine stand (natural origin or plantation) with little understory might also be an ecological desert, but if it lies within an ocean of aspen and northern hardwoods, the red pine represents an increase in community diversity. This would be a good thing. As such a stand changes with time, more light reaches the forest floor and an understory develops. Different expectations at different life stages. Not surprisingly, many rules of nature are not exactly "hard and fast".
Foresters are the professionals who are trained in forest ecology and understand how to manage a forest to bring about an increased and enhanced set of benefits for forest owners, and to the larger society as well. A century of applied forestry and generations of foresters have had a lot to do with building the rich forest of today from the emaciated condition following the historic logging and burning of the late 1800s.
take our forests for granted. It's rather easy to underestimate the role of
forests in the health of our environment, economy, and culture. Yet, the record
speaks for itself many times around the world and throughout time. It's usually
a mistake to use visual quality as a measure of forest quality. After all, since
when does an outer appearance speak to the inherent qualities that lie within?
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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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