The dogwood tree is good for more than its beautiful blossoms: It serves as an essential source of nutrients in Eastern forest ecosystems. Image credit: Wikimedia Commons
Dogwood trees throughout Eastern forests act as calcium pumps, pulling nutrients from deep in the soil and depositing it on the forest floor when its leaves fall each year. This process provides an essential nutritional source for a variety of forest species. Meanwhile, birds and small mammals feed on the tree's berries, which are rich in protein.
Indeed, dogwood trees play an important role in the health of the Eastern United States' forest ecosystems. An invasive fungus, however, is decimating the trees and—according to new research—prescribed forest fires may be the only hope for preserving them.SLIDESHOW: Hot Scenes From Raging Wildfires
The fungus, known as Discula destructiva, attacks the tree's foliage, the girdles the trunk with large cankers.
Michael Jenkins, a professor of forestry and natural resources at Purdue University, explained:
The disease has expanded across much of the flowering dogwood's range in North America...it pretty much decimates dogwood populations. In some cases, we have seen more than 90 percent mortality.
In the face of such severe destruction, forest biologists and conservationists began looking for a solution that could save the important tree.
Image credit: di_the_huntress/Flickr
Jenkins, along with Eric Holzmueller of Southern Illinois University and Shibu Jose of the University of Missouri, began looking at dogwood tree data. They noticed that in forests that had suffered at least two forest fires in the last 20 years, dogwood trees continued to flourish fungus-free.
To understand why this might be, they looked at the fungus it self. Discula destructiva, it turns out, favors a cool, moist, environment with little air movement. These conditions are most common in undisturbed forests—ones that have not been cleared by a fire in decades.
In these undisturbed forests, eastern hemlock trees have moved in to the space created by dying dogwood trees. The hemlocks create a lower canopy, making the forest cooler and moister—and more favorable for the fungus. This precipitates the destruction of remaining dogwood trees.
To combat this compounding effect, the researchers suggest the use of prescribed burns on a 10-year rotation. This would clear the forest, reduce the number of hemlocks, and possibly resuscitate the ailing dogwood population.
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