Minnesota’s deer czar, Leslie McInenly, knows that for a lot of hunters there can never be enough deer.

“It’s like me and chocolate,’’ she said.

But as the state launches a three-year process to reset its deer population — the first in nearly a decade — deer hunters won’t be the only ones at the table. There also will be white, red and jack pines, orchids and other wildflowers and all the species that depend on them.

The likely increased numbers of Minnesota’s favorite game animal will come at the peril of the state’s beloved pine trees and the native plants, insects and animals that live below them on the forest floor.

The state’s deer population exploded starting in the late 1990s, and, due largely to recent harsh winters, has since declined somewhat. But study after study shows that browsing by overabundant deer herds is crushing the biodiversity of northern and eastern forests. The threat they pose, say some forest ecologists, is greater than climate change.

In areas around Bemidji and Park Rapids, forest experts are projecting sizable loss of jack pine stands — partly because deer eat the new growth. With jack pine, red pine and the majestic white pine, any meaningful regeneration is now dependent on planting by hand or aerial seeding on prepared sites. Anti-browsing protections for the tiny trees and the cost of replanting stands that get wiped out by deer have made the process less successful and more expensive.

It’s a problem seen throughout the United States.

“We’ve already got more deer than the land can support,” said Gary Alt, a wildlife biologist now based in California who reduced Pennsylvania’s deer population to curtail the destruction of plant life that was harming that state’s $7 billion forest industry.

“If anything, it’s getting worse,” said Brian Palik, research ecologist for the U.S. Forest Service in Grand Rapids.

Between 1997 and 2006, Minnesota’s whitetail population soared from an estimated 733,000 to more than 1.1 million, prompting an outcry from foresters and ecologists that deer were wiping out the understory in the woods. The Department of Natural Resources responded by lowering deer density goals in many areas between 2005 and 2007. Increasing the legal take, especially for female deer, reduced the herd size, as planned. But recent harsh winters have crashed the population in some areas, leading to an outcry from hunters who complained at recent “listening sessions” that deer are too scarce. The 2013 hunting season produced a harvest of 172,000 deer, the lowest in 15 years.

“As a general consensus, people I talk to think the numbers are about half of what they were,” said Mike Staggemeyer, who hunts on private land south of La Crescent. “I would like to see a few more deer.’’

Deer populations across Minnesota vary according to habitat and are managed differently from area to area. Current density levels range from a high of 25 to 30 deer per square mile in the extreme southeast to only 3 to 5 per square mile in the far west. In much of central and north-­central Minnesota, where most deer are harvested, numbers hover around 20 to 25 per square mile.

Mark Johnson, executive director of the Minnesota Deer Hunters Association, said doubling the number would not be too much in some areas. Most hunters believe the state went “quite a ways” too far in lowering the population the last time around, he said.

“We are definitely at a low ebb,’’ Johnson said.

Deer debate begins

The latest rejiggering has started with a look at southeastern Minnesota, where a hunter-dominated citizen advisory team has called for increases in more than half of the region. The 21-member team, 18 of whom are deer hunters, did not propose any decreases. Its recommendations have been posted by the DNR for public reaction.

As Minnesota wades into the three-year process, McInenly said she expects to hear more from foresters, ecologists and timber companies as the evaluation moves northward. Farmers who suffer crop damage from deer and motorists who cross paths with them also will weigh in. And the DNR has its own costly fight against chronic wasting disease to consider as it changes density goals.

In the Arrowhead region, timber mill operator Jack Rajala has a different perspective on how many deer are enough. After years of fighting deer, he’s finally seeing low-enough numbers where browsing isn’t a problem for his young trees. Since the 1980s deer have eaten 1 million young white pines on his property even though the numbers in his part of the state are lower than many other areas. He learned to protect new seedlings with bud caps — paper scraps stapled to the trees’ leading growth stems. Even with lower densities, capping the seedlings is a necessity for about the first five years, until they are beyond deers’ reach.

“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.

“Deer are contributing to the shifting composition of the forest,’’ said Frelich, who has studied the deer-related loss of new-growth hemlock trees in the Porcupine Mountains of Michigan’s Upper Peninsula.

McInenly said deer hunters in Minnesota understand the need to keep the herd in check. Hunters went along with the deer reduction in 2005-2007 when foresters and ecologists were more vocal about browsing damage, she said. And it’s the DNR’s job to balance competing interests, especially when it comes to the “upper thresholds’’ for protecting healthy ecosystems, she said.

But the DNR can’t ignore the social reality of deer hunting and “certainly’’ listens to hunters, McInenly said.

For now, indications point toward a managed increase in the deer population, but no one knows what that number will be.

“We are trying to find the sweet spot, but I don’t think you ever land on the sweet spot,’’ McInenly said.