Chequamegon-Nicolet National Forest, Northern Wisconsin
Bringing Back Aspen
Aspen shows its beauty in all seasons, from pale green spring foliage to quaking yellow leaves in autumn. It yields valuable forest products from pulp for paper to chips for strandboard to biomass for generating electricity. Especially when it’s young, aspen provides food and homes for a broad range of wildlife. There are all sorts of reasons for keeping aspen a major component of our northern woodlands, and on Chequamegon-Nicolet National Forest, conservationists are working to do just that.
This stand of mature aspen is ready for a timber harvest./C. Fergus
The Chequamegon-Nicolet takes in 1.5 million acres in 11 counties in northern Wisconsin. There, conservationists have mapped out 12 areas where aspens have gotten too old to provide good habitat for ruffed grouse, American woodcock, golden-winged warblers, and other wildlife. In those areas, the aspens are approaching an age after which it will be much more difficult to regenerate them.
In the early twentieth century, rampant unregulated logging cleared most of the forest in northern Wisconsin. Big fires swept the land in the wake of this exploitative cutting, which was so widespread that it’s sometimes simply called “The Cutover.” In the wake of the fires, aspens came to cloak the landscape.
A Fast-Growing Tree
The tiny, airborne seeds of aspen let this tree quickly reforest areas where human-caused or natural disturbances remove the forest. Aspen also sprouts from its roots – underground networks that can cover acres. When it’s young (up to around 20 years of age), a stand of aspen is jungle-thick. Yet plenty of other plants grow among the crowded stems, because the trees’ foliage is relatively open, letting a good amount of light reach the forest floor.
After the harvest: Young aspen on the left, birch on the right, and plenty of thick, wildlife-friendly vegetation./C. Fergus
The richly diverse shrub and herb communities beneath young aspens produce abundant fruits and promote high numbers of insects. Many kinds of wildlife breed and nest in or beneath young aspens. And each summer, many different songbirds (including ones that breed in older forest) flock to these food-rich areas where their young can grow quickly and put on fat before migrating south in autumn.
Aspen is short-lived: The trees start to die out after about 50 years, at which point other longer-lived hardwood trees claim gaps in the forest canopy caused when the old aspens perish. Also, the aspens' underground root systems gradually become less vigorous and less able to send up new trees should a windstorm, fire, or logging operation remove the standing trees.
When Aspen Starts Dying Out
These days, there’s an overabundance of old aspen and not enough young aspen in the Chequamegon-Nicolet – part of a trend that holds true across much of the Upper Midwest. Forest inventory data predict significant declines in the amount of aspen, and also in paper birch, balsam fir, and jack pine, three other quick-growing, short-lived trees.
On the Chequamegon-Nicolet, conservationists laid out 12 parcels to coincide with former ruffed grouse management areas. There, commercial logging is regenerating wildlife-friendly aspen while delivering valuable forest products. Cutting the aspen spurs it to grow back densely and helps restore the health of the trees’ underground root systems.
Towhees build their nests on or near the ground in thick cover of young forest./J. Larkin
Managers are also using mechanized equipment to shear off alders, a type of shrub found in wet soils and in places where wetland and upland areas merge. Like aspens, alders also shoot up densely following cutting. While they’re at it, the conservationists are reopening grassy clearings that woodcock use for spring breeding and where grouse take their chicks to feed on insects, and reconditioning the hiking trails that folks use when hunting grouse and woodcock in the fall.
This landscape-scale project will create and renew 15,000 to 20,000 acres of young forest habitat over the next 40 years. Almost 3,000 acres of newly rejuvenated aspen will spring up in the next five years alone. Currently, timber harvests are underway in 9 of the 12 habitat areas.
Keeping the Right Balance
Dan Eklund is a forest wildlife biologist on the Chequamegon-Nicolet. “In the past, we’ve enjoyed the benefits of having a lot of young forest on the land,” he says. “But that’s changing as the years pass and our forests grow older.
“People often perceive of forests simply as forests; they don’t see that different elements fit together to create a productive forested landscape. With these 12 habitat projects, we can show the public that we need areas within the forest that are of different ages, have different types of trees, and occur in different arrangements on the land.
“To have a healthy ecosystem, you need to have some young forest around – sometimes those trees are jack pine, sometimes they’re aspen. We need to remember that a lot of animals that breed in mature forest also need young forest at one time or another – and also that a lot of animals that breed in young forest need mature forest as well.
“As far as aspen goes, deciding on the harvesting techniques isn’t the hard part – it’s convincing people that aspen just doesn’t live to be 350 years old. Aspens aren’t sequoias. But keeping them a strong part of our woodlands is valuable to many different kinds of animals, and it improves overall forest health. The key is keeping all of the different elements in the right balance.”
Funding and Partners
U.S. Forest Service, EPA – Great Lakes Restoration Initiative, Ruffed Grouse Society/American Woodcock Society, National Fish and Wildlife Foundation, Wildlife Management Institute
How to Visit
For maps and additional information, visit the website of Chequamegon-Nicolet National Forest. Dan Eklund can be reached at 715-762-5194 and deklund@fs.fed.us.
