Three of North America’s eight major biomes converge in Minnesota: Coniferous Forest, Deciduous Forest, and Prairie Grassland. Minnesota is the only place where these three communities come together, and one of the few nonmountainous regions on earth to contain any three biomes in such a small space.
This convergence results in a tremendous statewide biodiversity. On a macro scale the change from one to the next is quite sudden, though on the ground the zones co-mingle, creating biologically rich areas many miles wide that contain species from both.
The largest biome in Minnesota, Coniferous Forest, covers 40 percent of the state. While it only dips into a few northern reaches of the eastern United States, this region extends north across most of Canada and Alaska before petering out into arctic tundra. Vegetation must contend with shallow soils and a short growing season, so most species have evolved to economize energy use.
The dominant trees are pines (red, white, and jack), spruce, fir, aspen, and birch. The tallest tree is the eastern white pine, which often tops out above 100 feet, and Minnesota’s state tree, the red (Norway) pine, is not far behind.
Vast open peatlands, some of the largest in the world, are spread throughout the central and western parts of the region and contain tamarack, a conifer that sheds its needles in the winter, turning a beautiful orange in the process.
The Prairie Grasslands of the Great Plains follow the entire western border of Minnesota and sweep across most of the south. This is the state’s most fractured landscape, but the prairie that hasn’t been lost to the plow is some of North America’s most diverse. Nearly 1,000 species of grass and forb thrive in the nutrient-rich soils of the Minnesota prairie, and small individual plots can contain over 200 species.
Despite this incredible richness, five grasses—big and little bluestem, Indian grass, prairie dropseed, and porcupine grass—account for as much as three-quarters of the vegetative cover in dry prairies.
It’s the flowers that really capture the imagination, though: Favorites include wood lily, purple coneflower, gray-headed coneflower, pasqueflower, purple and white prairie clovers, goldenrods, and asters. Prairie wetlands, home to small white lady’s slippers and golden alexander, are scattered through the region, mostly in the north. Bur oaks, their thick bark resistant to fire, sometimes manage to invade a prairie, creating an oak savanna.
Though it covers most of the eastern United States, Deciduous Forest exists in Minnesota as just a narrow band separating the prairie and the coniferous forest. The most common trees are oak, maple, elm, basswood, hickory, butternut, birch, and aspen.
The sugar maple, turning bright yellow to deep reddish-orange, is the most spectacular fall-color tree. Spring sees a profusion of ephemeral wildflowers such as trillium, hepaticas, anemones, bellworts, and Dutchman’s britches that bloom before the canopy of leaves returns.
Other shade-tolerant species, such as asters, elm-leaved goldenrod, and woodland sunflower, wait until the summer to flower. North of Polk County onward into Canada, the forest consists mostly of scattered stands of aspen interspersed with the prairie—known as brush prairie or aspen parkland, it is sometimes considered a separate biome.
© Tim Bewer from Moon Minnesota, 3rd Edition