Mature stands of this upland forest community are dominated by white spruce (Picea glauca) and balsam fir (Abies balsamea), often mixed with paper birch (Betula papyrifera), northern white-cedar (Thuja occidentalis), eastern white pine (Pinus strobus), eastern hemlock (Tsuga canadensis) (within its range), balsam-poplar (Populus balsamifera), and trembling aspen (Populus tremuloides). Mountain-ash (Sorbus spp.) may also be present. Common understory herbs are large-leaved aster (Eurybia macrophylla), blue-bead lily (Clintonia borealis), Canada mayflower (Maianthemum canadense), wild sarsaparilla (Aralia nudicaulis), and bunchberry (Cornus canadensis). Most Wisconsin stands are associated with the Great Lakes, especially the clay plain of Lake Superior and the eastern side of the northern Door Peninsula on Lake Michigan. The boreal forest in Wisconsin is transitional between the mixed deciduous-conifer forests to the south and the spruce-fir dominated forests of Canada, so tree species richness is often greater here than in the boreal forests farther north. Of potential interest from the perspectives of vegetation classification and restoration, eastern white pine had the highest importance value of any tree in the Lake Superior region, as recorded during the original land survey of the mid-1800s.
