Earth Partnership for Schools



Boreal Forest, "Spruce-Moose Forest"

General: The boreal forest is a circumboreal forest meaning that it extends all around the world from northern North America to Northern Europe and Asia.

Distribution: Wisconsin is the southern tip of an extensive forest originating in Canada. Boreal forest is found along the shore of Lake Superior and near the tip of the Door County peninsula on Lake Michigan. Original area was 672,300 acres, or 1.92% total land surface of Wisconsin. Practically no remaining examples exist in Wisconsin today.

Physical Environment: A thick layer of leaf litter in a boreal forest indicates a slow rate of decomposition. Acidity of the soil and cold temperatures slow the activity of the fungi, bacteria, and animal decomposers.

Topography: Boreal forests grow on Lake Superior lowlands; sheltered, narrow river valleys; moist, steep, rocky land; and north and east slope aspects.

Microclimate: Boreal forests occur on sites that are significantly cooler then the surrounding areas. Winds blowing over the lakes greatly influence the microclimate of the forest. The lake breezes keep the summer temperatures cool, moisture abundant, and evaporation low. In the winter the temperatures are warmer, and the snow is deeper.

Composition: Species listed below are most likely found in the community.

Dominant Trees: Balsam fir, white spruce.

Common Trees: White pine, white cedar, white birch, trembling aspen, balsam poplar, large tooth aspen, red maple, mountain maple, and sugar maple.

Typical Shrubs: Beaked hazelnut, dwarf bush honeysuckle, gooseberry, and brambles.

Prevalent groundlayer: Canada mayflower, sarsaparilla, bluebead lily, bunchberry, starflower.

Structure: In Wisconsin, there are three distinct types of boreal forest; 1) old stands of relatively pure stands of conifers, 2) mixed conifer-hardwoods, or 3) dense balsam fir and white spruce under large, aging aspen or birch. The last two types represent successional change after a disturbance. Groundlayer species are evenly divided between spring and summer bloomers.

Soil: Dry to wet, clay to sandy loam. Acidic soil.

Major Soil Series: Gray Wooded and Podzol.


Summary of Soil Analysis:



p H



2785 p.p.m.


150 p.p.m.


35 p.p.m.


18 p.p.m.

Stability: Northernmost stands are very stable. Southern stands tend to be replaced by northern mesic forest. Depends on continuing disturbance, such as fire, insect attack, and windthrow to maintain itself. Without disturbance, a boreal forest degenerates rather than develops. A fire burns the thick, acidic litter layer, releasing nutrients and allowing seedling regeneration.
Typical Number of Species: Trees 32, Shrubs 56, herbs 240, Total 328
Species Density: 58
Guilds: Not available.
Wildlife: Gray jay, crossbills, grosbeaks, pine siskin, warblers, red-breasted nuthatch, red squirrel, snowshoe hare, porcupine.
Typical Examples: High Lake Spruce-Fir S.A., Gillen Nature Reserve, Vilas Co., and Red Cliff Indian Reservation, Bayfield Co.
Geographical Distribution: Centers on Lake Superior, from central Ontario, northern Michigan to NW. Minnesota, north to limit of hardwoods in Manitoba and Ontario. Boreal fingers down into the Appalachian and Rocky mountain ranges and along the West Coast.