The thick canopies of oak stands can prevent seedling oaks from taking root. Image: Carin Tunne
By Carin Tunney
Foresters throughout the Great Lakes region are destroying mighty oaks and other trees to regrow hardwood forests.
That may seem counterproductive, but forestry officials say oaks need special attention to maintain a diverse and healthy forest system. That means cutting down decades-old trees and clearing shrubs to encourage new oaks to grow.
The efforts include projects in every Great Lakes state.
A single oak seedling reaches toward the open sun of a mature oak forest. Image: Carin Tunney
The U.S. Department of Agriculture (USDA) and U.S. Forest Service are involved in seven regional projects on hundreds of thousands of acres as part of a national effort that started in 2014.
One project in southeastern Ohio spans 250,000 acres across 17 counties.
“For the first time since the 1940s, Ohio’s forests are no longer expanding in area,” said Christina Coulon, a public affairs specialist with the USDA Natural Resources Conservation Service. “However they are going through various changes that affect their characteristics and the benefits they provide.”
That means benefits to at-risk animal species that rely on Ohio’s oak
Wildlife officials say the migratory, cerulean warbler is experiencing one of the fastest declines of the warbler family. It nests in the oak forests of southeastern Ohio. Image: Wikimedia Commons
forests, such as cerulean and worm-eating warblers and the wood thrush, Coulon said. Foresters say rare snakes, butterflies and at-risk plants also depend on oaks. And deer and squirrels benefit from increased acorns.
State natural resources agencies and land conservancies engaged in new reforesting projects include these projects:
- more than $1 million pegged for a forest-regeneration project across 18 counties in south-central Indiana
- a $1 million dollar watershed restoration around Kinkaid Lake in southwestern Illinois
- a prescribed burn across 142 acres near the Trail of Tears State Forest in southern Illinois
- an effort to restore oaks on public and private land in the Superior National Forest area of in Wisconsin and Minnesota
- reforestation to improve habitats in the Susquehanna Watershed in southeastern New York
- More than 2,000 acres of state land in Kalkaska County, Michigan.
Woodlands that lack human intervention put species diversity at risk, said Dave Lemmien, a forest manager with the Michigan Department of Natural Resources (DNR).
Aging oaks create thick canopies that inhibit natural reseeding, he said. Shade-loving trees and plants take over, and the ecosystem suffers.
“They will grow just to certain size and that is it,” Lemmien said.
Elm, ash and beech seedlings dominate the floor of this well-established oak forest. Image: Carin Tunney
“You are not creating canopy gaps and allowing for natural generation for regrowth to occur.”
An even distribution of trees in terms of age and species also helps woodlands survive attacks by invasive species, Lemmien said.
“Obviously if our northern hardwood stands were made up of ash when the emerald ash borer was introduced to the state, we wouldn’t have any trees left at all because that would have wiped out all of them,” he said.
Lemmien is part of a new Michigan project to reforest 2,000 acres in Kalkaska County, near Grayling. Timber harvesting will encourage acorns and stumps with well-established root systems to sprout new trees.
Aging trees are more susceptible to disease and other threats, Lemmien said. A gypsy moth infestation already killed many of these oaks.
Many oak forests across the northeastern U.S. have not been reforested for more than 80 years, said Charles Ruffner, a forestry professor at Southern Illinois University.
Research shows some southern Illinois forests lost half of their oaks between 1980 and 2014. Shade trees, like sugar maple and beech are taking over.
After 30 years of forest research, the need for action has arrived, Ruffner said.
“When you don’t do anything in the woods for 80 years, forest succession — the change that happens in forests naturally — continues to happen,” he said. “In a generation or two, the forest has changed drastically, and then you spend your whole career trying to get it right again.”
The forestry master plan in Illinois includes efforts to reinvigorate forests throughout the state, including an oak regeneration project along the Trail of Tears in southern Illinois, he said.
The project uses prescribed burns to encourage natural seeding of new plants in oak forests. Prescribed burns are becoming popular because of increasing evidence of their effectiveness in restoring habitats, Ruffner said. Research shows that prescribed burns result in oak seedlings that are taller and larger in diameter.
People often associate burning with air pollution. Forestry officials say they use techniques to minimize it, such as burning only in suitable weather conditions.
But the advantages of burning outweigh the marginal effect on the atmosphere, said Benjamin Snyder with the Illinois DNR.
“It’s a natural disturbance that has been around for thousands of years and has affected how our forest established,” he said. “There is some smoke pollution involved with burning, but the benefits outweigh the short-term negative effects.”
Researchers say fires set by Native Americans once played a large role in restoring forests. They say increased fire prevention is detrimental to forest regrowth.
Prescribed burns also control invasive species, Snyder said.
Forestry officials say private landowners play a critical role in forest management. Many state efforts include educational outreach to landowners about forest regeneration, including cutting, burning and clearing shrubs to help preserve hardwood forests.
The Michigan DNR says it will consider prescribed burns in
Indiana forestry officials conduct a prescribed burn as part of forest management: Image: Indiana DNR
Kalkaska County if the forest needs extra encouragement to grow.
Indiana’s efforts include an 18-county reforesting project across public and private land. The state received a million-dollar federal grant, which includes outreach to landowners.
Previous reforesting efforts in Indiana resulted in a rebound of endangered plants and rare insects and the discovery of two new insects, according to a state report.