Diversity: Nature’s way | | cadillacnews.com

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“Diversity” is a buzzword these days. While in our society we struggle to describe what diversity should look like, Mother Nature has been the author of diversity all along. In recent years, this author has written articles on forest pests that plague the forest in our region. The latest was the gypsy moth. Most of these pests thrive because their favorite tree species often grow in uniform stands.

Pine bark beetle and heterobasid root disease thrive in pure stands of pine. Forest tent caterpillar grows in pure stands of sugar maple, oak wilt grows in pure stands of red oak, and gypsy moths thrive in pure stands of aspen or oak.

Nature has almost never created pure stands. The pure stands of aspen and jack pine that are often seen are the result of the great fires that followed the great timber days of the early 1900s. Given enough time, nature will always increase a diversity of species.

For the most part, uniform stands are easy to manage, much like farming. But agricultural farming produces a harvestable crop after one growing season. The forest takes decades to produce a harvestable product and pest problems often take years to accumulate in forests.

Most forest pest populations remain at a tolerable level until forest trees experience stressful conditions. Drought is one of the most obvious stressors that can lead to poor forest health, and unfortunately there is nothing forest owners can do to alleviate the lack of water. Only Christmas tree growers irrigate their tree crops. Many of our maples have severe dieback in their crowns.

Forest density is the second most common stressor that can lead to pest problems. Plantations are the most susceptible to this condition, especially pine and spruce. Plantings require thinning, often decades after the initial planting. Very often the landowner who plants is no longer the owner thirty years later and the understanding of the thinning required is lost. Pine trees do not thin out like aspen stands do. When planting density is not periodically reduced by thinning, bark beetle populations explode and kill many trees.

A third stressor is age. The age at which a tree will grow depends on the quality of the soil on which it grows. The relatively infertile sands of the Cadillac region do not allow trees to grow well beyond 80 years without showing signs of physiological decline. Our oak forests are good examples. Add other stressors and like this year we see many trees dying.

A fourth stressor is our large deer population. Tree seedlings are a large part of the white-tailed deer’s winter and spring food source. Where deer populations are high, understory forest diversity is generally low. The understory (seedlings and saplings) is the next forest.

In hardwood stands, the loss of entire tree species due to invasive alien pests has reduced the diversity of species that nature has developed to maintain a healthy balance. Having a diversity of species not only keeps a forest healthier, but it also means there will always be replacement when the trees die. In many ways, we haven’t often seen an ecologically sound forest.

So what can we do as forest owners to help increase diversity?

Improve the soil by encouraging woody debris to rot on the forest floor.

Discourage the increase of deer populations.

Allow hardwoods to grow under pine plantations.

When thinning a stand of northern hardwoods, do not always remove species other than maple.

Do not save the harvest of all beech trees in the face of death from beech bark disease.

Find and protect the remains of elms and ash trees. There are more than you think. White ash seedlings are making a comeback. Try to encourage seedling propagation of these trees. Maybe there’s a good reason why they’ve survived so long. Ask a forester how best to do this.

If you would like more information, please contact District Forester Larry Czelusta at 231-775-7681 ext 3 or email him at larry.czelusta@macd.org.

Larry Czelusta is Outreach Forester for Wexford, Missaukee and Kalkaska counties. For more information on trees and forestry, contact Larry by phone, email, or drop by the USDA Service Center office at 7192 E. 34 Road (Boon Road) in Cadillac.

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