Native plant community spotlights for Rochester Plateau and Blufflands

Southern Dry-Mesic Oak-Hickory Woodland

Bur oak, shagbark hickory, American elm trees

Commonly found on steep, exposed, south- and west-facing bluffs in southeastern Minnesota, this deciduous community is often adjacent to and blends with grassy bluff prairies. Bur oak, shagbark hickory, American elm, black walnut, and boxelder are characteristic canopy trees with northern pin oak, white oak, northern red oak, and black cherry often present. The shrub‑layer is often dense with American hazelnut, gray dogwood, poison ivy, prickly ash, prickly gooseberry, and red raspberry in addition to shagbark hickory, American elm, black cherry, and hackberry saplings. Important ground-layer species include woodland sunflower, white snakeroot, elm-leaved goldenrod, shining bedstraw, Canadian and gregarious black snakeroots, and heart-leaved Alexanders.

Older canopy trees in this community often feature open and spreading branches, indicating they likely grew in more open conditions than may currently exist on the site. Historically, open-grown trees benefited from frequent mild surface fires that affected this community about every 15 years. Larger, catastrophic fires where much less frequent. Since 1900, modern fire suppression has led to the loss of this mosaic of oak openings and a closing of the forest canopy. To keep this 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 using prescribed burning to create openings, especially adjacent to bluff prairies, to maintain an interrupted canopy with open growing conditions.

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Southern Wet-Mesic Hardwood Forest

landscape showing variety of American elm, red elm, rock elm, basswood, black ash, green ash, hackberry trees

This lowland deciduous forest community is found in the rich stream valleys of southeastern Minnesota. The composition of canopy species varies, but often features sugar maple, American elm, red elm, rock elm, basswood, black ash, green ash, hackberry, boxelder, and bur oak. Butternut, black walnut, and black maple are also present in some stands. The understory often contains a variety of species including blue beech, chokecherry, Missouri gooseberry, and canopy tree seedlings. Herbaceous plants such as false rue anemone, blue phlox, hispid buttercup, appendaged waterleaf, Virginia spring beauty, white trout lily, and yellow trout lily often blanket the forest floor. Other common and often abundant species include Virginia waterleaf, cleavers, and wood nettle.

These beautiful, nutrient-rich communities attract recreationist but are also vulnerable to a number of invasive species. Monitor the understory and woodland edges for invasive plants such as garlic mustard, buckthorn, Japanese barberry, wild parsnip, and other weedy invaders. Taking fast action to eradicate them protects this biologically important southeastern Minnesota ecosystem

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Southern Dry-Mesic Oak Forest

landscape showing a variety of northern red oak, white oak, and basswood trees

This deciduous community is most commonly found on the north-facing slopes of bedrock bluffs but is also present on bluff crests and west- or east-facing slopes. The most common canopy species are northern red oak, white oak, and basswood with shagbark hickory occasionally present. The density and abundance of seedlings and saplings in the shrub and sub-canopylayers depends on the available light filtering though the canopy and usually contains seedlings and saplings of the dominant canopy species. Black cherry, chokecherry, American hazelnut, Missouri gooseberry, and pagoda dogwood are also present in the shrub-layer. Ground-layer plants such as lady fern, Clayton's sweet cicely, wild geranium, hog peanut, and white snakeroot typically cover 25 to 100 percent of the forest floor.

Catastrophic disturbances were historically rare in this community, while events such as light surface fires that created pockets of tree loss were much more common. Creating medium to large gaps—up to an acre—allows oak and hickory seedlings to access the full sunlight they need to succeed. Making smaller gaps—single trees or small clusters—may favor basswood. Either strategy will help create diverse age groups among your trees similar to the effects of fires in the past, improve wildlife habitat, and help your woods resist environmental stress.

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Southern Mesic Maple-Basswood Forest

landscape showing sugar maple trees in the sumer

Present on sites that have been historically protected from fire, this deciduous forest is most often found on middle and lower slopes on north and northeast facing bluffs. The canopy is strongly dominated by sugar maple, with lesser amounts of basswood and northern red oak present. Sugar maple, bitternut hickory, basswood, prickly gooseberry, and chokecherry are common in the shrub-layer. Important ground-layer species include Virginia waterleaf, bloodroot, yellow violet, large-flowered bellwort, wild leak, blue cohosh, and early meadow-rue.

A forest with mixed age classes, heights, and tree species will be more resilient to Minnesota's changing climate. To diversify your forest, create openings by conducting scattered removals of individual trees ready for harvest or removing small patches of trees. This will encourage smaller sugar maple and basswood trees in the understory to grow into the gaps created by the harvest while discouraging sun-loving trees like red and bur oak. Repeat harvesting individual or small patches of trees every 10–20 years to maintain a diverse maple-basswood dominated forest. If you want to increase the amount of oaks, clearcut your woods one to two years after pre-planting oaks to a density up to 600 seedlings per acre. Remove competing trees and shrubs until oaks dominate the canopy. Care must be taken to protect remaining canopy and understory trees from damage during the harvest.

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Southern Terrace Forest

landscape showing a variety of American elm, green ash, hackberry, basswood, boxelder, silver maple trees.

This nutrient-rich plant community occurs throughout southern Minnesota where occasionally flooded sites transition to upland forests and floodplains. These conditions make terrace forests the most diverse tree community in the state, often containing a mix of: American elm, green ash, hackberry, basswood, boxelder, silver maple, black ash, black walnut, cottonwood, and other species. Their understories are much more diverse than floodplain forests and feature abundant spring ephemeral flowers. Species include: wood nettle, Virginia waterleaf, spotted touch-me-not, tall coneflower, Virginia bluebells, and eastern narrow-leaf sedge.

These forests are vital to protecting the region's water quality and provide important wildlife habitat. Many of these forests have been converted to agriculture fields or lost due to invasion by reed canary grass, which dominates sites where light reaches the forest floor. Reed canary grass greatly impedes the establishment of tree seedlings. Consider enhancing or expanding the forested stream buffer by planting native tree seedlings and controlling invasive species to help the region's water quality and wildlife habitat. You will also improve forest diversity, including high-value black walnut, which could provide a hefty return in years to come.

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Spotlight: Floodplain Forests

Floodplain forest floor along the Vermillion River coveredsowing silver maple, black willow, and cottonwood trees.

Floodplain forests occur in areas along major rivers that seasonally flood their banks. Typically dominated by silver maple, black willow, and cottonwood, these forests provide important habitat for many wildlife species and serve as a major migratory corridor in your region. A number of rare bird species depend on this habitat for feeding and nesting such as prothonotary warblers, cerulean warblers, and red-shouldered hawks. Large areas of floodplain forests in southern Minnesota have been lost to urbanization and conversion to agriculture. Now these forests, which once formed continuous bands of habitat along the major rivers in southeastern Minnesota, persist as broken chains of forest patches. Damning creates an additional challenge by greatly reducing the annual pulse of flooding that maintains this habitat. Additionally, the spread of reed canary grass, an invasive plant, and excessive flooding caused by climate change prevents native seedlings from establishing. A specific type of this habitat in your region is highlighted in Section 5.

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