Putting Down Roots for Future Forests

A typical summer field day for Kirsten Rhude begins by driving to the boat launch, filling a canoe with birch, cedar, and maple tree saplings, and paddling through the St. Louis River Estuary until she arrives at an island to plant them on. As Stewardship Coordinator at the Lake Superior Reserve, she and her colleagues have worked with Wisconsin Conservation Corps crews to plant 23,000 trees as part of a Great Lakes Restoration Initiative grant. Funded by the Environmental Protection Agency, this regional collaboration is removing invasive species and replanting wetland forests in the Estuary. Their goal? Preserve the region’s wetland forests for the future.

“We want to help these wetland forests become more resilient. We’re seeing high ash mortality due to emerald ash borer and there aren’t many young trees in the understory,” says Rhude. “We hope planting will give these areas a head start so that they continue to provide wetland forest habitat, protect manoomin restoration sites, and slow water during floods.”

Many of the estuary’s islands are home to wetland forests that are mostly made up of black and green ash trees, which makes them especially susceptible to emerald ash borer. The beetle’s larvae burrow under a tree’s bark and form galleries, effectively girdling the tree and preventing it from getting water and nutrients. As the ash tree dies, invasives like buckthorn and honeysuckle establish themselves in the understory, which makes it harder for ash seedling trees to grow.

Black ash is culturally important for the Ojibwe people—whose ancestral territory spans the St. Louis River Estuary—because of its use in making items such as baskets, sticks for baaga’adowewin (traditional La Crosse), and the dikinaagan, a cradleboard for babies. Black ash also helps protect another resource important to the Ojibwe: manoomin or wild rice. That’s why Rhude and her Reserve colleagues are focusing their efforts on islands in front of bays where manoomin restoration is underway. If the trees on these islands die, their roots won’t hold the soil and the islands could erode, exposing the wild rice.

The team has planted 16 different species so far, with a goal of encouraging a diverse wetland forest. Experts from the Wisconsin Department of Natural Resources (DNR) and the Fond du Lac Band of Lake Superior Chippewa consulted on which types of trees would do well in these conditions now, and in the future, as the climate shifts. Indigenous partners also recommended species that are culturally important. 

The work hasn’t been without challenges. These areas are dominated by water-loving ash for a reason; it can be difficult for other types of trees to take root in the water-saturated soil. Ash trees also consume a lot of water. If many of them die, the soil could become even wetter, making it more challenging for other trees to get established there. By planting trees now, Rhude and her colleagues hope to give them a head start.

“We are monitoring the success of the trees we plant now to inform which species will be used in future restoration projects,” says Rhude. “I’m very aware of the fact that I’m planting trees that we hope will be there long after I’m gone; it’s a humbling legacy.”

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