By Bill Allen
At first glance, Minnesota’s Northwoods seem almost untouched.
A closer look shows they’ve been significantly altered. The kinds of trees present, their relative numbers, their age and their distribution across the landscape are very different than what they would be if left to nature. The health and diversity of our forests have been reduced, making them less resilient to climate change, disease, invasive species and natural events.
The Nature Conservancy seeks to restore forests in Minnesota. Restoration requires an active, hands-on approach, guided by science-based methods. It’s an approach that includes tree-planting, harvesting timber and prescribed burns in order to promote new generations of native trees.
Minnesota’s northern forests were legendary at the start of the 20th century – famous for large stands of beautiful and valuable trees, particularly white pines.
White pines and other conifers have survived, but in smaller numbers, and the trees that have replaced them are mostly aspen (also called poplar) and birch, two fast-growing tree species that are now the mainstay of Minnesota’s timber industry. Deer thrive in these transformed forests and preferentially browse white pine and white cedar seedlings, making it difficult for the trees to stage a comeback. Other factors, such as fewer fires, also impede the return of white pine (white pines survive fire better than many other trees). When the remaining old pines eventually fall, there are few new pines to replace them.
The Conservancy is working with partners to help bring back white pine and other long-lived conifers to Minnesota’s Northwoods, benefiting both the forest and forestry. That means planting conifer seedlings, protecting them from deer and pruning young trees to discourage diseases like blister rust. Selective logging of large areas can also play a role by mimicking natural disturbances that create openings for new generations of trees yet avoid older and increasingly rare native trees that serve as sources of seed.
Over time, these practices will create a mosaic of trees in all growth stages, producing a range of habitats like that found in nature. More habitats mean the forest can support more kinds of Northwoods species like moose, pine marten, Canada lynx, northern goshawk and spruce grouse. More variety in forest trees also means a wider range of forest products. Forestry operations can produce non-traditional products such as balsam boughs as well as pulp products.
No one organization or landowner can accomplish this work alone.
The Nature Conservancy is partnering with the Minnesota Forest Resources Council, Wolf Ridge Environmental Learning Center, the Minnesota Department of Natural Resources (DNR), the U.S. Forest Service and Lake County in the Upper Manitou Forest landscape to manage the forest as a whole rather than strictly by ownership boundaries.
In the Sand Lake/Seven Beavers landscape, the Conservancy is working in much the same way to restore forests in collaboration with St. Louis County, Lake County, DNR and the U.S. Forest Service.
The Manitou and Sand Lake/Seven Beavers projects are expected to become models for how to ensure that forests remain productive and healthy for people and nature alike. “It’s an on-the-ground demonstration of how to combine economically-feasible logging with restoring the diversity of our forests,” said Chris Dunham, Forest Manager for the Conservancy in Minnesota.
Bill Allen is a volunteer writer for The Nature Conservancy.December 29, 2011