The area of east-central Minnesota known as the Mille Lacs Uplands and Glacial Lake Superior Plain subsections includes all or parts of Aitkin, Benton, Carlton, Chisago, Crow Wing, Isanti, Kanabec, Mille Lacs, Morrison, Pine, and Sherburne counties.

The soils of the Mille Lacs Uplands are coarse-textured near the southwestern edge of the region but become increasingly clayey to the northeast. The forests in areas of coarser drift (clay, silt, sand, gravel, and boulders deposited by glaciers) are dominated by northern red oak, while areas of clayey soil have forests of sugar maple, aspen, and birch.

Sandy terraces along the St. Croix River and small sand plains in other parts of the section have fire-dependent woodlands or forests of jack pine, bur oak, northern pin oak, and aspen. Fire-dependent pine, oak, and aspen forests are also present occasionally with mesic hardwood forests on coarse till and drumlins (teardrop-shaped hills of rock, sand, and gravel). Peatlands and other wetland communities are present mostly as inclusions within the broad areas of hardwood forest. 

The small region near Duluth called the Glacial Lake Superior Plain is composed mostly of clayey sediments. The landscape is highly dissected by the Nemadji River and its tributaries, characterized by steep-sided ravines. The ravine slopes support wet-mesic forests of aspen and paper birch mixed with conifers such as white spruce, balsam fir, northern white cedar, and white pine; and mesic forests of sugar maple, basswood, and paper birch.  High areas between the ravines represent flat, clayey, poorly drained remnants of the glacial lake bed. These sites most commonly have wet forests dominated by black ash mixed with northern white cedar and yellow birch.

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 by Paul Wray, Iowa State University, 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

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 

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

Black hickory is native to the central U.S. primarily in Missouri and Arkansas, with the northern end of its range extending into Illinois. It is a small to medium sized tree, with 5-7 leaflets per compound leave. The bark is not shaggy like other hickories, and is dark gray and coarsely rough-textured.  Like other hickories, black  hickory supports many species of insects, mammals, and birds. It's hardy to zones 5-9. Learn more about black hickory on the Illinois Wildflowers page.

Photo by Brenda K. Loveless, Wildflower Center Digital Library

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

Sugarberry is a large tree with light green, simple, alternate leaves that have a rough leaf surface but smooth leaf edges. Sugarberry bark is warty. Hackberry, a cousin native to Minnesota, has rough leaves with toothed edges and bark that is warty and ridged. Both trees have small edible fruit. Sugarberry is considered hardy from plant zones 5a-10b. To learn more about this species and how to identify it visit the NC State Extension Horticulture page.

Photo from iNat by sambiology

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

Sweetgum is a large deciduous tree with star-shaped leaves and large spiky fruits known as gumballs. In the fall, the leaves turn bright red, purple, yellow or orange. The tree produced a resinous gum underneath the bark that can be used for chewing gum, incense, and medicines. Sweetgum is hardy to zone 5-9 and is native to the southeastern part of the U.S. Learn more about sweetgum on the NC Extension Horticulture page.

Photo by Forest and Kim Starr, Starr Environmental, Bugwood.org

Yellow-poplar or tulip tree, is a tall, slender tree with unique alternate leaves with 4-lobes that resemble the silhouette of a cat face. It also has large pale yellow tulip-shaped flowers in early summer after the leaves emerge. It is considered hardy from plant zone 4-9. To learn more about this species and how to identify it visit the NC State Extension Horticulture page or the UMN website.

Photo from iNat by conorflynn.

Osage-orange is a medium sized tree with large baseball size yellow-green, inedible, fruit on female trees. The name is derived from this orange-like fruit. The leaves are simple, elongated egg-shaped with smooth edges. Thorns form below the leaves on new shoots. The bark is furrowed, orange-brown to gray-brown with an irregular criss-crossed pattern. It is considered hardy from plant zone 4-9. To learn more about this species and how to identify it visit the NC State Extension Horticulture page or the UMN website.

Photo from iNat by mariposa21157

Blackgum has a wide range, from southern Ontario, across the eastern U.S., to Mexico. It's hardy to zones 4-9.  Its leaves are simple, alternate, and elliptical in shape. It produces blue berry-like drupes in September and October. Its fruit and flowers is prized by pollinators and other wildlife. Learn more about blackgum on the NC State Extension Horticulture page.

Photo by Franklin Bonner, USFS (ret.), 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

This medium-sized oak tree or shrub  has unique shiny, leathery leaves with W-shaped lobes at the top. As with all oak leaves they arranged oppositely on the twig. The bark is black to dark brown with rectangular plates or blocks. It will have acorns and brown to deep red leaves in the fall.  It has been mentioned for planting in Minnesota and is considered hardy from plant zone 6a-9b. To learn more about this species and how to identify it visit the NC State Extension Horticulture page.

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

Photo from iNat by dillon_freiburger.

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

Sassafras is an aromatic, medium-sized tree. The leaves are alternately arranged and variable with smooth edges shaped as ovals, mittens or three lobbed. It is considered hardy from plant zone 4a-9b. To learn more about this species and how to identify it visit the NC State Extension Horticulture page.

Photo from iNat by vis5121.

Chittamwood, or gum bumelia, is native to the south-central U.S. and northeastern Mexico. This is a tree of many names - in addition to chittamwood or gum bumelia, it can be called by some other interesting names such as gum bully, gum woolybucket, shittamwood, or false buckthorn. It's hardy to zones 6-10. It has simple, alternate, oblong leaves and the branches can develop thorns. It also produces small black fruits that are eaten by wildlife, and pollinators visit the flowers. Learn more about chittamwood on the NC State Extension Horticulture page.

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