MICHIGAN FORESTS FOREVER TEACHERS GUIDE

CLEARCUTTING . . .        IS IT NECESSARY?

Clearcutting is a subject of considerable controversy throughout the nation as well as in Michigan. However, it is a legitimate forest management tool that has specific applications to meet particular objectives.  It is the only way to regenerate many forest types without incuring the negative side effects of natural processes, such as wildfire, severe windstorms, and insect/disease epidemics.  

Clearcutting is a method of timber harvest and regeneration. It involves cutting all or most of the trees in an area at one time.   Clearcutting is not what is done to develop a new subdivision or strip mall!   Any timber that might be sold (which would be a good thing) from such a development is . . . well . . . development or land use change, not forestry.  Many people dislike the loss of forests for development, and such deforestation is an issue in Michigan (although net forest area is increasing), but clearcutting for forestry is a practice that regenerates the forest.  Young forest habitats, and the species that specialize in those habitats, are on the decline across North America.  This is a concern among many people.  

Clearcutting is used as a method of regenerating or rejuvenating certain kinds of trees, and forest types, that cannot tolerate shade. It is also used when a forest type conversion is planned, often from low quality hardwoods to pine, on sites best suited for pines.

3. But why not cut only the larger ones and leave the little ones?

Almost all the trees in these shade-intolerant forests are the same age. The small ones are not necessarily young ones, but more likely stressed and unhealthy trees.  Second, trees vary in their ability to grow up under the shade of other trees.  Sugar maple and balsam fir, for instance, will grow well under shade, while jack pine and aspen grow very poorly in shaded situations.

No.  Although clearcutting is appropriate in some types of forests, methods that leave various numbers of trees standing (selection and shelterwood) are preferred and practiced in most other situations. Clearcutting may not be the best practice on certain types of soils, slopes, or other factors, even though the timber types would benefit.

Let’s look at two of Michigan’s largest timber types and how clearcutting helps their regeneration and continuity.

Aspens (popples). There are two species of aspens native to Michigan; quaking aspen and bigtooth aspen.  They are among nature’s "pioneer trees".  That is, they are trees that will start new forests after fires, floods, windstorms, or other catastrophic disturbances.  Aspens tend to grow in groups called clones (genetically identical trees) that are supported by a common root system.  These interlaced roots will send up new sprouts, called suckers, if the trees are cut when alive and vigorous.  The suckering is stimulated by two factors; the warming of the ground by the sun due to the removal of shade, and the absence of sprout-suppressing chemicals produced in the tops of the parent aspen trees.

Thus, clearcutting provides two essential stimuli for development of a vigorous, new aspen stand.  The cleaner the cut, the better it works.  Small-diameter stems of maple and oak, if left, will develop wide-spreading crowns and shade out the young aspen underneath, so they must also be cut if the objective is to start a new aspen forest.  Most of the time, other tree species will regenerate in the aspen clearcuts.  However, they are frequently "hidden" by the overwhelming abundance of aspen suckers.  As the aspen naturally thins itself (slower-growing suckers die from lack of sunlight), the other tree species become increasingly observable over time.

Jack pine is another pioneer species.  This one commonly occupies some of the driest, sandiest sites in Michigan.  Few other tree species can survive and thrive on these sites, while jack pine can develop into commercially valuable stands.  For this reason, it may be the only tree species choice available in many areas of northern Michigan.

Jack pine’s place in the ecological scheme of things is to restock areas after forest fires.  Its cones contain a resin, which prevents them from releasing their seeds.  The cones stay in the tree tops for many years where they will open after a fires sweeps through the stand.  This phenomenon is called "serotiny".  The heat melts the resin but usually passes through too quickly to burn the cones.  The after the fire, the seeds fall on the freshly-burned earth, a perfectly prepared seedbed. The fire has prepared the seedbed, released the seeds, and destroyed the overhead shade all in one pass.

Clearcutting mimics the effects of the fire by removing the shade and scuffing-up the ground to prepare the seedbed.  The cones will reach high enough temperatures to melt the resin if they are within about one foot of the ground.  If this natural seed source does not regenerate the stand, seedlings are sometimes planted.

Should you have an opportunity to visit the aftermath the 22,000-acre Duck Lake fire (2012), you will see oceans of naturally regenerating jack pine .

Aspen and jack pine are preferred by deer, grouse, and other wildlife as places to live and as sources of food.  Timber harvest provides more than half of the wood products and forestry jobs that are important to Michigan’s people and economy.  Forest inventory trends show that these "young" forests are on the decline, threatening a suite of wildlife species that depend on these young forest habitats, including some threatened or endangered species.  

Clearcutting may be useful in several other situations.

Oak, particularly on poor soils, may be clearcut (1) if trees are mature and if enough young trees 3 feet or more in height are present to establish a new forest, or (2) if trees are mature and enough stump-sprouting is anticipated to create a new oak forest, or (3) if other tree species would be planted on the site, or (4) to make openings for wildlife habitat.

Red pine, if trees are mature and a new forest would be established by planting or by young trees already present.  Red pine are also intolerant of shade .

Spruce, fir, and cedar may be clearcut in strips or patches that are small enough to allow seeds to blow in from nearby trees.  If deer densities are high, cedar regeneration will probably be unsuccessful.  Deer are the single greatest threat to forest regeneration and forest species diversity in the Lake States.

Because it is shocking to see areas abruptly changed from dense forest to treeless openings.  The logging debris is unsightly, even in a well-handled job.  Because the new trees take a few years to become noticeable, it is perceived as wanton destruction rather than planned renewal.  Often young aspens and oaks are not recognized as trees, but are thought of as "brush".  This also contributes to the misconception that clearcutting fails to regenerate forests and contributes to deforestation.

Yes.  The visual effects of clearcuts can be softened by varying the shape and by leaving certain trees or groups of trees within the clearcut opening.  Many clearcuts can be made into pleasing temporary vistas in this way.  Changing people’s perception of clearcutting can only be done through education.

10. Are we cutting more than we can sustain in Michigan?

No.  Forest surveys done by the U.S. Department of Agriculture Forest Service have shown that we are growing nearly twice as much as we are cutting, on a statewide basis.  Timber harvest is monitored by the Forest Service and the Department of Natural Resources to avoid over-cutting.  Michigan’s forests are still recovering from the cutting practices of the previous century and we cannot allow that kind of over-harvest to happen again.  Regular forest inventory and planning assures that Michigan’s public forests will be sustained for future generations.

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Original text from a document by the Michigan DNR, modified by MSU Extension.

	This website was developed and created by Michigan State University Extension for the teachers of the State of Michigan.

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