The mighty oak isn't so mighty after all.
That is the growing reality in Minnesota, where red, white and bur oaks struggle to regenerate because of sapling-munching deer, invasive species and modest commercial demand, the latter a root cause for forests composed largely of older trees and relatively few young trees.
"The oak forest in southeast Minnesota is one our national habitat priorities," said Tom Glines, regional development director for the National Wild Turkey Federation. "It isn't what it used to be and what it is becoming is not what hunters and others who enjoy forest recreation will want in the future."
As such, Glines encourages turkey hunters to look beyond their gun barrels and into the future.
"The oaks that have long provided acorns for turkeys, deer, squirrels and other species to eat are not being adequately replaced," he said. "Instead, the forest is converting to buckthorn, honeysuckle, maple, basswood and other less wildlife-friendly species. It's not good. A maple doesn't drop an acorn."
Minnesota's oak plight has been long in coming. Before settlement, wildfires swept the state, and in doing so burned the brush and other plants that competed for the direct sunlight that young oaks need. As settlement went on, the biggest and best oaks were harvested. Shade-tolerant understory species spread like crazy, particularly unwanted buckthorn, as the forests evolved. Today, the majority of all of Minnesota's oak stands are 60 to 90 years old, with oak trees 40 years old or younger representing the smallest percentage. In fact, according to the Minnesota Department of Natural Resources, there are more oaks 100 years old or older than there are oaks age 40 and younger.
Glines said changing this age imbalance is a challenge. "The landscape is big, budgets are often small, and battling buckthorn is expensive. Realistically, partnerships are the only solution because no one entity can do it alone."
Larry Gates agrees. Gates is the chairman the Minnesota Forest Resources Council's Southeast Landscape Team. A longtime resident of the southeast, Gates and other team members aim to reinvigorate forest management on a 13-county landscape that covers 5 million acres. It is a big task. About 14.5% of that land — 725,125 acres — is forested.
"The key to meaningful change is helping private landowners see and solve the problem," Gates said. "Most of the land in southeast Minnesota is privately owned. That's where most of the oaks are. And that's where most of the oaks will disappear over time unless we manage invasive species, develop long-term consistent funding strategies that cross all ownerships, and obtain broad public support for sustainable forest management."
On a personal level, Gates is doing his part to sustain oak on his property by direct-seeding hardwoods, hand-planting seedlings and suppressing invasive species. The direct seeding involves collecting large volumes of nuts from a variety of hardwoods, broadcasting with a fertilizer spreader, and discing them to a depth of 1 to 2 inches. By this process, Gates is retiring about 5 acres of agricultural land per year. A DNR forestry division cost-sharing program helps offset his expenses, and his seedlings are thick and vigorous.
"Personally, I see great potential for creating young oak forests on field edges that abut blufftops," Gates said. "In the old days, farmers didn't plant crops as close to the edge as they do now. A blufftop oak buffer compensation initiative could result in many positive benefits for recreation, ecology and the economy, including less sediment in trout streams, more high-quality habitat for wildlife, and commercial timber opportunities."
Partnerships are key
Matt Weegman, district biologist for the turkey federation, said his organization is increasing technical assistance to private landowners. In the months ahead, he said, the turkey federation will hire a forester who will work out of the DNR conservation service office in Rochester. "It's a similar approach to what Pheasants Forever is doing in the prairie," Weegman said. "We are doing this as part of our national 'Save the Habitat; Save the Hunt' initiative that aims to conserve or enhance 4 million acres of critical habitat in the years ahead."
Still, Weegman said it is important to partner with public landowners, too. He oversees 10 oak habitat improvement projects on state lands that are paid for by the Legacy Amendment's Outdoor Heritage Fund. These projects involve removing buckthorn, planting oak and taking steps to help it grow. This is being done, in part, because about 65 percent of the state's oak stands are past the preferred rotation age of 80 or so years, and the habitat value of these trees is eroding. Once an oak tree hits about 100 years old its ability to produce reliable acorn crops decreases, as does its ability to re-sprout from a stump.
"In recent years Minnesota has put a lot of emphasis on wetland, prairie and aspen management but less emphasis on oak forests," Weegman said. "That's a concern we are trying to address because a mostly old forest is not a healthy forest."
Weegman said private landowners concerned about their oak stands should seek advice from their soon-to-be-hired turkey federation biologist in Rochester, a private consulting forester, the DNR forestry office, or the county soil and water conservation district office.
"Oaks are amazing trees, but they are not fast out of the blocks," Weegman said. "Landowners who want to grow oaks can benefit greatly from the experience of others who've done the same."
C.B. Bylander is a freelance writer. He lives near Baxter, Minn.
