The area of northern Minnesota known as the Agassiz Lowlands and Littlefork-Vermilion Uplands subsections includes all or parts of Beltrami, Clearwater, Itasca, Koochiching, Lake of the Woods, Marshall, Pennington, Roseau, and St. Louis counties.

This region is shaped by the deposits from Glacial Lake Agassiz during the last glacial period. These clay-rich deposits contributed to the widespread formation of wetlands, such as lakes, bogs, and fens across the northern part of Minnesota.

The following species are not currently native to Ecoregion 1, but this region's future climate may be suitable  to support habitat for these species. Extension Forestry is interested in learning more about these species, and we want to know if any of these species are already present on the landscape in Region 1. Learn more about each species using the drop-down buttons below.

Image credit: USDA Forest Service Northern Research Station

American hornbeam is medium sized understory tree, native to much of eastern MN but considered migration potential to ecoregions 1 and 2. This tree is sometimes called musclewood because the smooth-barked trunk looks like the ripped muscles of an elite runner. It's considered hardy from plant zones 3a - 9b. It produces noticeable catkins in early summer and very small nuts in late summer. To learn more about this tree visit the NC State Extension Horticultural page.

Photo from iNat viola2020

Bitternut hickory, a tall broadleaf tree , native to southeastern quarter of Minnesota and small packets of northern Minnesota but considered migration potential for ecoregions 1, 2 and 10.  Its name was inspired by the inedible nuts and it has alternate, pinnately compound leaves with 7 -9 leaflets. The  bright yellow buds are a distinguishing characteristic. It's considered hard from plant zones 4-9.  To learn more about identification visit the UMN website and the NC State Extension Horticulture page.

Photo leaf and bud by Paul Wray & Chris Evans, Bugwood.org

Shagbark hickory is native to the central and eastern United States, and can be found growing in southeastern Minnesota. This species is considered migration potential for ecoregions 1, 2, 3, 4, 6, and 10. Like other hickories, it's a large broadleaf tree with alternate, pinnately compound leaves with 5-7 leaflets. It can be distinguished from other hickories by its mature bark, which is shaggy, light gray, and separating into thick vertical strips that seem to be sloughing off the trunk. Learn more about shagbark hickory, visit the UMN website and the NC State Extension Horticulture page.

Photo by Rob Routledge, Sault College, Bugwood.org

This small understory tree that has conspicuous small purple flowers along the stem in early spring. It's considered hardy from plant zones 4a-9b. To learn more about this species and how to identify it visit the NC State Extension Horticulture page or the University of Wisconsin-Madison Extension website. This tree is not considered native to Minnesota and is planted in some communities including Rochester and the Twin Cities.

Photo from iNaturalist by m_whitson 

White ash is native to the eastern U.S. and can be found in southeastern Minnesota. Like other species of ash, it has opposite, pinnately compound leaves with five to nine leaflets.  The leaflets are clearly stalked and can be differentiated from green ash (short stalks) and black ash (sessile/no stalk) by the longer stalks on white ash leaflets. It can also be distinguished from black ash and green ash using the buds, which are rounder and shorter than the buds of black ash and green ash (both of which are more pointed and may resemble Hershey's Kisses). White ash is hardy to zones 3 to 9. Learn more about white ash on the UMN website, and hone your ash identification skills using this resource from University of Wisconsin-Green Bay.

Forest health threat: Please be aware that emerald ash borer (EAB) kills white ash, in addition to the rest of Minnesota's ash species.

Photo by Joseph OBrien, USDA Forest Service, Bugwood.org

Honeylocust is a large deciduous tree with alternate and compound leaves that have many small, round leaflets. Wild-grown honeylocust trees have large thorns, while other varieties lack the thorns. A member of the legume family, honeylocusts have long seed pods. Honeylocust is native to the central U.S. and the northern end of its range extends into Iowa. It's hardy to zones 3-8. Learn more about honeylocust on the UMN website and the NC State Extension Horticulture page.

Photo by Franklin Bonner, USFS (ret.), Bugwood.org

Black walnut is a medium to large overstory tree with leaves that are alternate and compound, with 15-20 long and narrow leaflets. The fruit is green and fleshy and about the size of a baseball, with an edible nut inside. The wood of black walnut is extremely valuable for wood products, including furniture, lumber, and paneling. Black walnut is native in southeast Minnesota, and is hardy to zones 4-9. Learn more about black walnut on the UMN website.

Photo from Rebeckah D. Wallace, University of Georgia, Bugwood.org

Eastern redcedar is a coniferous tree with thin, peeling bark and two different forms of needles. Most needles are dark green and scaled (somewhat similar to northern white cedar), while other needles sharp and awl-shaped (more similar looking to hemlock or spruce needles). It produces a blue berry-like cone that is preferred by birds during the winter. Eastern redcedar is hardy to zones 2-9 and is native to southern Minnesota. Eastern redcedar may become aggressive near native grasslands. Learn more about eastern redcedar on the UMN website.

Photo by Joh Ruter, University of Georgia, Bugwood.org

Red mulberry is very rare in Minnesota and should be reported anywhere in the state. It's a small, understory, shade tolerant tree that is often confused, and can hybridize with, non-native white mulberry, Morus alba.  Red mulberry leaves are dull, rough on the top and slightly haired on the underside and have small pointed serrations on the leaf edge. White mulberry leaves are shiny, smooth on the top and the serrated edges are larger and less pointed. Berries are likely present around the 4th of July. Red mulberry is considered hard from plant zones 5-10.  For more about mulberry identification visit this Purdue University publication.  In 2021, Extension ran another participatory science project looking specifically for rare red mulberry, project results and details can be found here.

Photos: leaves by Sally Weeks, Purdue University, fruit by David Stephens, Bugwood.org 

Eastern cottonwood is a large, dominant canopy tree planted in urban areas and found naturally in moist, well drained sites and along riverbeds. Large trees are preferred nesting places for bald eagles. Cottonwood is native to southern Minnesota but considered migration potential to ecoregions 1, 2 & 10 along the Canadian border. It's considered hardy for plant zones 2 - 9. Cottonwood's almost triangular shaped, simple, alternate leaves are fairly easy to identify.  To learn more about this species visit the UMN website and the NC State Extension Horticultural page.

Photo by Paul Wray, Iowa State University, Bugwood.org 

White oak is a long-lived overstory tree that is native to most of the eastern U.S., and the northern end of its range extends into east-central MN. White oak prefers moist, nutrient-rich sites and its acorns are an important food source for many wildlife species. A member of the white oak group, this tree has round lobes that are deeply divided. White oak is hardy to zones 3 through 9. Learn more about white oak on the UMN website.

Forest health threat: White oak is susceptible to oak wilt, a fungal pathogen that kills oaks. Oak wilt kills white white oaks are less quickly than red oaks (such as northern red oak and northern pin oak).

Photo by Chris Evans, University of Illinois, Bugwood.org

Swamp white oak is a large overstory tree that is native to southeast MN and much of the eastern and central U.S.  As a member of the white oak group, swamp white oak has rounded lobes, but not nearly as deeply divided as white oak. Some of the leaves on swamp white oak can resemble a diamond in shape. The undersides of swamp white oaks are light green and slightly hairy. Swamp white oak is hardy to zones 3-8. Learn more about swamp white oak on the UMN website.

Forest health threat: Swamp white oak oak is susceptible to oak wilt, a fungal pathogen that kills oaks. Oak wilt kills white white oaks are less quickly than red oaks (such as northern red oak and northern pin oak).

Photo by Paul Wray, Iowa State University, Bugwood.org

In the red oak group, black oak is a large overstory tree that looks similar to northern red oak. The acorns on black oak are elliptical in shape, and the leaves have 7-9 shallow or deep lobes. Acorns are an important food sources for many wildlife species. Black oak is native to the southeast corner of MN, and is hardy to zones 3-9. Learn more about black oak on the UMN website.

Forest health threat: Black oak is very susceptible to oak wilt, a fungal pathogen that kills oaks. Oak wilt kills red oaks more rapidly than white oaks. 

Photo by Chris Evans, University of Illinois, Bugwood.org.

Eastern hemlock is a large, dominant canopy conifer tree native to small pockets of Minnesota. It's listed by MN DNR as endangered so cannot be taken, imported, transported or sold. It has small cones and small flat needles and dark brown-gray, fissured or ridge bark. It's considered hard from plant zones 3a-7b. Hemlock wood adelgid has killed many hemlock trees southeast of MN. To learn more about identification visit the UMN website and the NC State Extension Horticulture page.

Photo by Bill Cook, Michigan State University, Bugwood.org