“If you bring the herd back up, it will hurt the conifers,’’ said Rajala, who wrote the 1998 book “Bringing Back the White Pine.’’
Mark White, a forest biologist for the Nature Conservancy, said he’s demonstrated what a deer-free forest can look like by fencing them out of a large plot of woods on the North Shore. Inside is thick, lush plant life and healthy young trees. Outside, the forest floor is sparsely vegetated, with few trees.
“It’s so well studied, there’s really no debate,’’ said White, who asserts that too many deer — not climate change — pose the biggest threat to forests in Minnesota, Wisconsin, Michigan and farther east.
Rajala and other forest experts believe that the preferences of Minnesota’s 500,000 deer hunters — who annually pay $19.6 million to the state in license revenue — will continue to trump ecological concerns. The low end of acceptability for hunters is still at a level that changes forests for the worse, they say.
“We are at that point,’’ said Mike Locke, a longtime DNR forester based in Bemidji. “If you want a lot of deer you are not going to have a lot of jack pine or white pine.’’
Locke was part of a 2006 state SWAT team, including wildlife managers, that studied why state forest land in a large triangular region including Backus, Bemidji and Park Rapids wasn’t meeting its goals to regenerate trees. Deer, drought and diseased seedlings were the main culprits and one recommendation the team agreed on was to keep local deer populations “at levels that will ensure pine species can regenerate and grow, ’’ Locke said.
But the deer numbers didn’t change. Pine regeneration “seems to be a minor factor’’ in setting deer population goals, he said. Deer densities of 10 animals per square mile — a level foresters can work around without too much spending on seedling protection and replanting — is not acceptable to hunters.
“It’s pretty clear that nobody is really going to politically stand up and say we are going to decrease the number of deer that are out there,’’ Locke said.
Gary Alt, the biologist who was appointed by Pennsylvania Gov. Tom Ridge to decrease deer herds, said the story is similar in nearly every big deer hunting state. Hunters overprotect female deer to increase fawn production, multiplying their chances of shooting a buck. As the herd increases, they get used to seeing a lot of deer and then revolt when game managers try to lower populations.
“They pay the bills, so [states] keep them happy,’’ said Alt, who experienced death threats in Pennsylvania and wore body armor to public meetings.
Alt said he foresees a time when deer populations become so unbalanced that some states will authorize commercial culling for food, supplanting hunters as a herd management tool.
Johnson of the Deer Hunters Association said foresters sometimes exaggerate depredation by deer, ignoring other factors that stifle new trees. He said most hunters don’t see a need for densities to be as high as they were during peak population in the mid-2000s, when there were 50 deer per square mile in some areas. But “something in between’’ would be fair to hunters and protective of the ecosystem, he said.
The costs of browsing
Lowering deer densities wouldn’t necessarily solve the browsing problem either, Locke said, because even small groups of deer have “hammered’’ large pine plantings. Many foresters believe that seedlings from commercial nurseries are extra tasty to deer because they contain more nutrients than trees that grow from seeds cast from aircraft.
There is also a considerable cost to taxpayers in protecting forests from hungry deer. In the nine years that ended in fiscal 2012, the DNR spent about $2.75 million on bud-capping and spraying repellent on seedlings. National forests in the state also spend money annually on deterrents. Palik said a contractor recently submitted a bid to bud-cap pine seedlings on a 500-acre site at a cost of $185 per acre, or $92,500 per year.
DNR wildlife and forestry officials from Locke’s area revisited the deer debate last year, producing a draft report on how to manage pine regeneration and deer populations in the northwest part of the state. The report noted that there are fewer hunters now and more land has been put off limits to hunting due to development or leasing — factors that diminish deer hunting as a tool to keep herds in check.
The draft report projected that by 2025 there could be a steep decline in the area’s jack pine cover based on losses of 15,000 to 16,000 acres that occurred between 1990 and 2006.
For the environment, selective browsing by deer also means a reduction in other trees and plants, including red oak, certain lillies, orchids and other plant species, said Lee Frelich, University of Minnesota forest biologist. The overall effect is a cascading drop-off in certain insects, less habitat for animals, fewer songbirds, less grouse and pheasant and the disappearance of various berries, Frelich said.