Native Plant Community Spotlights for Mille Lacs Uplands and Glacial Lake Superior Plan

Central Dry Oak-Aspen (Pine) Woodland

landscape image of forest floodplain with pin oak and quaking aspens.

This native plant community is considered imperiled based on its rarity and threats facing the remaining parcels. The plant community develops on level, permeable (porous), sandy soils that do not retain snowmelt or rainfall for very long. These environmental conditions occur in this region, most notably on terraces along the St. Croix River. Historically, fires that reached the crowns (tops) of trees and mild surface fires were common, occurring approximately every 9 years. Frequent fire disturbance in this community lead to a more open canopy that covered only about 50-75 percent of the forest ceiling. Forests were most often dominated by deciduous trees, especially northern pin oak and quaking aspen, however some sites were dominated by jack pine. The shrub layer is often dense, with abundant American hazelnut and tall blackberries.

The historical disturbance regime has been greatly altered with modern fire suppression. To keep this rare native plant community healthy, you should consider management activities that mimic the frequent mild to severe fires that once shaped this ecosystem. You might consider a strategy of creating openings to maintain the interrupted canopy cover and perform prescribed burning in these openings when possible.

Learn more about Central Dry Oak-Aspen (Pine) Woodland


Northern Wet Ash Swamp

forested swamp with black ash

Northern wet ash swamps are primarily found on mucky soils in shallow basins and on low, level terrain near rivers, lakes, or wetlands that typically have standing water in the spring that drains by late summer. The shrub, subcanopy, and canopy layers of this plant community are all dominated by black ash, often at the near exclusion of other species. In the Mille Lacs Uplands, however, this plant community may also contain some yellow birch, red maple, quaking aspen, and balsam poplar in the canopy. Lady fern, dwarf raspberry, and alpine enchanter's nightshade are common and often abundant in the ground layer.

Concern for this plant community is especially high due to the threat posed by a small green beetle from Asia called the emerald ash borer, or EAB. EAB has been found on two edges of your region in the Twin Cities, in northern Wisconsin (along Lake Superior), and in Duluth. This wet forest community would be significantly altered or eliminated if EAB spreads from these areas due to the dominance of black ash. EAB can be quickly spread through moving firewood, so to protect this important plant community you should only burn local firewood and report suspected outbreaks of EAB in your area. This community is also vulnerable to aggressive invasive plants such as glossy buckthorn, narrow-leaved cattail, hybrid cattail, and reed canary grass. Monitoring the understory and edges of your northern wet ash swamp for these invasive plants—and taking fast action to control them—can help protect this biologically unique Minnesota ecosystem.

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Central Mesic Hardwood Forest

heavly forested landscape showing red oak and sugar maples

The canopy of this common east-central Minnesota plant community was historically dominated by northern red oak, basswood, and sugar maple. Common understory plants include chokecherry, pagoda dogwood, prickly gooseberry, and beaked hazelnut, along with sugar maple, basswood, ironwood, and northern red oak seedlings and saplings.

Historically, catastrophic disturbances were rare. Events that resulted in partial loss of the tree canopy, especially light surface fires, would have occurred approximately every 40 years. The consequence of fire suppression and settlement in the past century has promoted more sugar maple, ironwood, and quaking aspen than was typical for this community. These increases came mostly at the expense of red oak, which no longer dominates this plant community like it once did. Oak trees can outcompete sugar maple and ironwood in large gaps. If you want to keep oak in your woods, you can tailor your firewood harvesting strategy to achieve this goal. Creating gaps that are a ¼- to ½-acre in size are best for regenerating red oak. Larger gaps allow aspen to dominate. For best results, target this activity in areas where some oak saplings and seedlings are already present. In contrast, creating small gaps by removing single trees or small clusters will favor sugar maple, red maple, and basswood. Similar to the effects of fire in the past, either strategy helps create diverse age groups among your trees, which creates better wildlife habitat and helps your woods resist environmental stress.

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Lakeshore showing reed grass with sandbar willows and a pine tree.

Lakeshore is prevalent in east-central Minnesota. Shores may be sandy or muddy and could contain a variety of terrestrial and aquatic plants depending on the season and current water level. Just above the normal water level you may find shrubs and forbs such as sandbar willow, spotted touch-me-not, and swamp milkweed. Below the normal water level you may find broad-leaved cattail, an assortment of sedges and rushes, and floating plants like water lilies and pondweeds.

A variety of ecosystems, from upland forest to lowland swamp, surround these lakes. While proper management along the shore can protect it from wave damage, how land is managed near shorelines also plays a key role in erosion control. Forests help filter runoff and hold soil in place, whereas agriculture and lawns can add soil, fertilizer, and pesticides to the runoff that flows into lakes. It is important to consider the impacts that all land use and management activities have on your lake, even beyond the shores.

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Spotlight: Deciduous Forests With Wetland Openings

Large tracts of mature deciduous forest provide important habitat for many wildlife species in your region. This habitat is particularly valuable to wildlife when it contains a diversity of scattered wetland openings. Salamanders and rare Blanding's and wood turtles make their homes in these valuable wetland forest areas. This habitat is also important for a number of bird species that depend on mature forests such as red-shouldered hawks and cerulean warblers. This habitat is under pressure from increased fragmentation and development that reduce the size of forest patches and lead to the drying of wetlands. Care should be taken to avoid creating large clearings within this important wildlife habitat that could further fragment these mature deciduous forests and contribute to changes in the local water cycle.

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