The area of north-central Minnesota known as the St. Louis Moraines and Tamarack Lowlands subsections includes all or parts of Aitkin, Carlton, Cass, Crow Wing, Itasca, and St. Louis counties.

These areas have been shaped by the glacial history of Minnesota, just like the rest of the state. Rolling hills in this area are caused by glacial deposits called moraines. Lowlands cover a large part of this region as a result of ancient lake plains, where glaciers previously melted and left behind flat topography with lacustrine (lake drainage) deposits. The Sax-Zim Bog is a great example of this landform.

The low-lying topography and wet conditions led to the accumulation of slowly decomposing vegetative material called peat on top of those lacustrine deposits. These conditions created the large areas of bogs that we see today, characterized by tree species such as black spruce and tamarack, but also a great diversity of bird species. The Sax-Zim Bog is a very popular destination for Minnesota’s birders.

The following species are not currently native to Ecoregion 4, 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 4. Learn more about each species using the drop-down buttons below.

Photo credit: Sparky Stensaas

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

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). 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, 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 invasive 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 

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 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 

Pignut hickory has alternate, pinnately compound leaves with 5-7 leaflets. Like other hickories, it produces nuts that are valued by wildlife but are quite bitter. Settlers fed the nuts to their pigs, hence the name pignut. Pignut hickory is native to much of the eastern and central U.S., but is not native in MN. This species is hardy to zones 4-9. Learn more about pignut hickory on the NC State Extension Horticulture page.

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

Mockernut hickory, also know as white hickory, has mostly white wood and leaves similar to the other hickories. The species epithet "tomentosa" (covered in hair) refers to the fuzzy stems near the buds.It produces edible nuts for up to 200 years, and provides habitat to many species of wildlife, including many butterflies and moths. Mockernut hickory is native to much of the eastern, central, and southeastern U.S. It is hardy to zones 4-9. Learn more about mockernut hickory on the NC State Extension Horticulture page.

Photo by Vern Wilkins, Indiana University, Bugwood.org

American beech is a large, long-lived overstory tree with characteristic gray bark that remains smooth into maturity. American beech can be found growing along ravines and valleys, and the northern end of its native range extends into Illinois. It can be found as far south as Florida. The nuts are a preferred food for many wildlife species and its large crown provides habitat for many species of mammals and birds. American beech is hardy to zones 3-9. Learn more about American beech on the UMN website.

Forest health threat: Beech bark disease kills American beech due to the combination of the introduced beech scale insect and several fungal species. Beech bark disease has been detected as far west as eastern Wisconsin.

Photo by Rob Routledge, Sault College, Bugwood.org

Sycamore is a large deciduous tree with reddish brown, scaly bark at the base that appears white nearer to the crown. The leaves look similar to grape leaves, and the twigs are zig-zag patterned. It produces large spherical fruit. Sycamore is native across the eastern U.S. and its northern range extends into Iowa. It's hardy to zones 4-9. Learn more about sycamore on the NC State Extension Horticulture page.

Photo by Rob Routledge, Sault College, Bugwood.org

Shumard oak is a large tree in the red oak group that is native to much of the southeastern U.S. Like other oaks, it provides many benefits to wildlife through food and habitat. The acorns are ovoid with shallow caps. Shumard oak is hardy to zones 5-9. Learn more about Shumard oak on the NC State Extension Horticulture page.

Forest health threat: Shumard 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 T. David Sydnor, The Ohio State University, Bugwood.org

Post oak is a species in the white oak group that is native to much of the eastern and southeastern U.S. The leaves can be distinguished from other white oaks by the two middle lobes that are square-shaped, which gives the leaves a cross-like appearance. Post oak is hardy to zones 5-9. Learn more about post oak on the NC State Extension Horticulture page.

Forest health threat: Post 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