Creating the future forest

LAKE VERMILION STATE PARK— There’s a remarkable dividing line here between the old and new portions of what is now called the Lake Vermilion Soudan Underground Mine State Park. The original park, centered around the former mining operation, encompassed about 1,200 acres, most of it comprised of impressive old growth red and white pine forest.
The newer portion of the park, acquired from U.S. Steel in 2010, encompassed nearly 3,000 acres of recently logged land, which was regenerating heavily to young aspen and birch. That not only established a visual divide between the two parts of the park, it created a long-term forest management challenge for park officials.
While the aspen and birch were still quite young when the state acquired the newest segment of the park, they have continued to grow older in the 16 years since the acquisition, and the forest is now decidedly middle-aged. Unlike the red and white pine that dominate the old section of the park, both aspen and birch are short-lived, sun-loving trees, that require disturbance, either logging, fire, or windthrow, to regenerate. Given that large-scale logging is typically frowned upon in state parks and prescribed burning comes with significant challenges and risks, resource managers here are using modified approaches to help transition the forests for the long haul. In state parks, planners typically focus on the long-term, and in this case, it’s about slowly steering the forest in the right direction.
For state forest managers, like Tony Lenoch, who is based out of the DNR’s regional office in Grand Rapids, it can be a bit of trial and error. From the moment the state enlarged the Lake Vermilion park, it became clear that some kind of forest transition would eventually be needed for the new section.
At first, Lenoch said he experimented with underplanting, which is just what it sounds like— planting seedlings underneath an existing tree canopy. Some shade tolerant species, like white pine, can do well in theory, growing very slowly until the existing tree cover begins to break apart, through some kind of disturbance or decay, giving the young seedlings access to sunlight which then prompts rapid growth.
But as those young white pine seedlings waited for “release,” often for years, they became vulnerable to browsing from the many white-tailed deer that make the park their home. With the help of Minnesota Conservation Corps crews, Lenoch turned to bud-capping, which typically involves stapling a piece of paper around the terminal bud of a seedling. It’s not just a tedious task, it’s one that must be repeated year after year until the terminal bud is beyond the reach of deer, to be effective.
“We’ve tried that approach,” said Lenoch. “I bet we’ve dropped 10,000 trees in that park, but not many have survived. They grow so slow [under the shade] and deer tend to get them even if bud capped,” he said.
That’s prompted a change in direction, said Lenoch, focusing on creating small clearings of about an acre or two in areas dominated by birch or pockets of balsam fir that have been hit by spruce budworm. Work crews have then planted a mix of white and red pine, along with red oak, in the clearings and used rolled metal fencing to protect each new seedling from deer. Lenoch said he’s gone with that mix of trees in part because pine are signature trees in the North Country, while the red oak are likely to do better as the climate continues to warm. The trees are planted at a lower density than is typical of more production-oriented stands, and the trees will likely be mixed with regenerating birch, which will often form attractive clumps of trees from freshly-cut stumps.
Lenoch, with help from his five-member crew, have piled the cut trees and branches from the clearings, and Lenoch said he’ll begin burning the piles once there’s some snow on the ground. To date, most of the work can be found along Wawa Way, a trail that begins near the park’s self-serve entrance.
While the work won’t result in the removal of all of the aspen and birch, the scattered pockets of pine and oak will provide a seed source to gradually replace these short-lived species as they die off, leaving a more diverse forest of longer-lived tree species for future generations to enjoy. Lenoch said that’s already happening along the park’s forest divide as pine are beginning to spread easterly into the newer section of the park. Eventually, that stark forest divide will disappear entirely.