This forested minerotrophic wetland is dominated by northern white-cedar (Thuja occidentalis) and occurs on rich, neutral to alkaline peats and mucks throughout much of northern Wisconsin. Balsam fir (Abies balsamea), black ash (Fraxinus nigra), and spruces (Picea glauca and P. mariana) are among the many potential canopy associates. The understory is rich in mosses, lichens, liverworts, ferns, sedges (such as Carex disperma and C. trisperma), orchids (e.g., Platanthera obtusata and Listera cordata), and wildflowers such as goldthread (Coptis trifolia), fringed polygala (Polygala pauciflora), and naked miterwort (Mitella nuda), and trailing sub-shrubs such as twinflower (Linnaea borealis) and creeping snowberry (Gaultheria hispidula). A number of rare plants occur more frequently in the cedar swamps than in any other habitat. Older cedar swamps are often structurally complex, as the easily wind-thrown cedars are able to continue growing with now-vertical branches growing into new trees and developing new root systems where the trunk is buried in the soil. Some of the canopy associates (especially white spruce as well as the occasional white pine) have the potential to reach heights considerably beyond those usually attained by cedar, producing a multi-layered canopy. The tall shrub layer is often well-developed and may include speckled alder (Alnus incana), alder-leaved buckthorn (Rhamnus alnifolia), wild currants (Ribes spp.), and mountain maple (Acer spicatum). Canada yew (Taxus canadensis) was formerly an important tall shrub in cedar swamps but is now rare or local due to deer browsing.
Seepages, springs, and spring runs contribute to stand complexity and provide critical habitat for additional plants and animals. Cedar swamps are relatively common in depressions that receive mineral-enriched groundwater, and can be associated with both ground moraine and outwash landforms.
