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For information on Wisconsin's natural communities, contact:
Ryan O'Connor
Natural Heritage Inventory Ecologist

Northern Wet-mesic Forest

State Rank: S3S4     Global Rank: G3?   what are these ranks?


Detailed Community Description from Ecological Landscapes of Wisconsin

General natural community overview

Counties shaded blue have documented occurrences for Northern Wet-mesic Forest in the Wisconsin Natural Heritage Inventory database.

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.

Defining Characteristics and Similar Communities

Northern wet-mesic forests are characterized by calcium-rich neutral to alkaline peat or muck soils, usually with a strong groundwater component and a canopy dominated by northern white-cedar. They are most similar to northern hardwood swamps, especially as both black ash and northern white-cedar can be canopy associates in both communities. In general, sites that are dominated by hardwoods are best typed as hardwood swamps, while sites dominated by conifers are best typed as northern wet-mesic forest, though both types may occur and intergrade across large wetland complexes. Northern wet-mesic forests also have some similarities with northern tamarack swamps but are more minerotrophic and dominated by northern white-cedar rather than tamarack, though tamarack may be a minor component of some cedar swamps. Northern wet-mesic forests often occur in forested swales associated with Great Lakes ridge and swale community complexes. In these cases, they would be classified a component of the larger ridge and swale community.

Rare animals

Species of Greatest Conservation Need

Wisconsin Wildlife Action Plan graphic

The following Species of Greatest Conservation Need are listed according to their level of association with the Northern Wet-mesic Forest natural community type, based on the findings in Wisconsin's 2015 Wildlife Action Plan.

Scores: 3 = high association, 2 = moderate association, and 1 = low association. See the key to association scores for complete definitions.

Four-toed SalamanderHemidactylium scutatum3
Pickerel FrogLithobates palustris2
Mink FrogLithobates septentrionalis1

Ants, wasps, and beesScore
Indiscriminate Cuckoo Bumble BeeBombus insularis2
Confusing Bumble BeeBombus perplexus1
Sanderson's Bumble BeeBombus sandersoni1
Yellowbanded Bumble BeeBombus terricola1

Aquatic and terrestrial snailsScore
Bright GlyphGlyphyalinia wheatleyi2
Brilliant GranuleGuppya sterkii2
Eastern Flat-whorlPlanogyra asteriscus2
Ribbed StriateStriatura exigua2
Transparent Vitrine SnailVitrina angelicae2
Black StriateStriatura ferrea1
Cherrystone DropHendersonia occulta1
Dentate SupercoilParavitrea multidentata1
Six-whorl VertigoVertigo morsei1

Evening GrosbeakCoccothraustes vespertinus2
Gray JayPerisoreus canadensis2
Long-eared OwlAsio otus2
Olive-sided FlycatcherContopus cooperi2
Swainson's ThrushCatharus ustulatus2
American WoodcockScolopax minor1
Black-backed WoodpeckerPicoides arcticus1
Boreal ChickadeePoecile hudsonicus1
Common GoldeneyeBucephala clangula1
Golden-winged WarblerVermivora chrysoptera1
Least FlycatcherEmpidonax minimus1
Northern GoshawkAccipiter gentilis1
Red-shouldered HawkButeo lineatus1
Ruby-crowned KingletRegulus calendula1

Butterflies and mothsScore
Gray CopperLycaena dione1
West Virginia WhitePieris virginiensis1

Grasshoppers and alliesScore
Crackling Forest GrasshopperTrimerotropis verruculata2
Bruner's Spur-throat GrasshopperMelanoplus bruneri1
Clear-winged GrasshopperCamnula pellucida1
Spotted-winged GrasshopperOrphulella pelidna1

Little Brown BatMyotis lucifugus3
Northern Flying SquirrelGlaucomys sabrinus3
Water ShrewSorex palustris3
Silver-haired BatLasionycteris noctivagans2
Woodland Jumping MouseNapaeozapus insignis2
American MartenMartes americana1
Northern Long-eared BatMyotis septentrionalis1

Wood TurtleGlyptemys insculpta2

Please see Section 2. Approach and Methods of the Wildlife Action Plan to learn how this information was developed.

Rare plants

The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.

Scores: 3 = "significantly associated," 2 = "moderately associated," and 1 = "minimally associated."
Scientific Name Common Name Score
Amerorchis rotundifolia Round-leaved Orchis 3
Calypso bulbosa Calypso Orchid 3
Carex capillaris Hair-like Sedge 2
Cypripedium arietinum Ram's-head Lady's-slipper 3
Cypripedium parviflorum var. makasin Northern Yellow Lady's-slipper 3
Equisetum palustre Marsh Horsetail 1
Galium brevipes Swamp Bedstraw 2
Geum macrophyllum var. perincisum Large-leaved Avens 2
Gymnocarpium robertianum Limestone Oak Fern 3
Listera convallarioides Broad-leaved Twayblade 1
Malaxis monophyllos var. brachypoda White Adder's-mouth 3
Menegazzia terebrata Treeflute 3
Platanthera hookeri Hooker's Orchid 1
Polemonium occidentale ssp. lacustre Western Jacob's Ladder 3
Pseudocyphellaria crocata Yellow Specklebelly 2
Ranunculus lapponicus Lapland Buttercup 3
Vaccinium vitis-idaea Mountain Cranberry 1
Valeriana uliginosa Marsh Valerian 3


The following Ecological Landscapes have the best opportunities to manage for Northern Wet-mesic Forest, based on the Ecological Landscapes of Wisconsin Handbook.

Map of the Ecological Landscapes of Wisconsin.

Major (3 on map)
A major opportunity for sustaining the natural community in the Ecological Landscape exists, either because many significant occurrences of the natural community have been recorded in the landscape or major restoration activities are likely to be successful maintaining the community's composition, structure, and ecological function over a longer period of time.

Important (2 on map)
Although the natural community does not occur extensively or commonly in the Ecological Landscape, one to several occurrences do occur and are important in sustaining the community in the state. In some cases, important opportunities may exist because the natural community may be restricted to just one or a few Ecological Landscapes within the state and there may be a lack of opportunities elsewhere.

Present (1 on map)
The natural community occurs in the Ecological Landscape, but better management opportunities appear to exist in other parts of the state.


Wisconsin Wildlife Action Plan graphic

What are conservation actions?

Conservation actions respond to issues or threats, which adversely affect species of greatest conservation need (SGCN) or their habitats. Besides actions such as restoring wetlands or planting resilient tree species in northern communities, research, surveys and monitoring are also among conservation actions described in the WWAP because lack of information can threaten our ability to successfully preserve and care for natural resources.

Threats/issues and conservations actions for natural communities


The following are additional considerations for Northern Wet-mesic Forest in Ecological Landscapes with opportunities for protection, restoration, and/or management. For more information, see the Wildlife Action Plan.

Central Lake Michigan Coastal

Local abundances of cedar-dominated forest occurred historically, associated with the Niagara Escarpment in the northeastern portion of this Ecological Landscape. Extensive land development has reduced the abundance of this type, and restricted opportunities for conservation.

Forest Transition

Historically, cedar forest was rare here; what there was occurred mostly in the eastern part of the Ecological Landscape in what is now the Chequamegon-Nicolet National Forest and on the Menominee Reservation.

North Central Forest

Sites on the Chequamegon-Nicolet National Forest are often found in wetlands fed by nutrient-enriched groundwater, including areas between drumlins on loamy till soils. Popple River Cedars and Jones Swamp in the Nicolet National Forest feature cedar-dominated forests. In the North Central Forest, much of the type has been converted, or is converting to other types, and restoration methods are lacking. Over the long term, opportunities for restoration in this landscape are high because of the abundance of forested lands and the extent of public ownership.

Northeast Sands

The combination of glacial outwash sands and alkaline groundwater make this a significant landscape for this type. Examples include Miscauno Cedars State Natural Area (Marinette County), Waupee Lake Research Natural Area (Oconto County, on the Chequamegon-Nicolet National Forest), and Brazeau Swamp (Marinette County Forest). Several of the largest and least disturbed stands known from the upper Midwest occur on tribal reservation lands.

Northern Highland

Only a few occurrences of this type are known from this Ecological Landscape, but several of them are exceptional for their size, the mosaic of associated communities, and very high plant and animal diversity. These include Toy Lake Swamp and Rice Creek Cedars and Fen (proposed State Natural Areas in Vilas County), and Trout Lake Conifer Swamp State Natural Area (Vilas County).

Northern Lake Michigan Coastal

Forests dominated by northern white cedar were historically common within this Ecological Landscape, particularly on dolomite outcrops. Opportunities exist for protecting more of this type, but land prices are often prohibitively high. Partnerships with land trusts and other conservation organizations should continue to be encouraged to protect additional northern wet-mesic forest sites through acquisition, conservation easements, and incentive programs.

Northwest Lowlands

Several large occurrences of this type were present historically, but few remain today. Existing sites merit protection.

Northwest Sands

One major historic occurrence is known, adjacent to the Northwest Lowlands Ecological Landscape.

Southeast Glacial Plains

Though this type is of limited occurrence here, several important examples persist along the eastern margins of the Ecological Landscape, very close to the climatic Tension Zone. Cedarburg Bog State Natural Area (Ozaukee County) and Jackson Marsh State Wildlife Area (Washington County) provide habitat for many plants and animals that are rare or absent elsewhere in southeastern Wisconsin. Excessive deer browse and invasive plants are major problems at both of these sites.

Superior Coastal Plain

Historically, the northern wet-mesic forest intergraded with the boreal forest. There are opportunities for restoring and protecting this community and managing it as a block with boreal forest and hemlock-hardwoods. On the Apostle Islands, white cedar occurs in an unusual mix with eastern hemlock (often dominant), red maple, eastern white pine, mountain maple, and Canada yew. Northern white cedar is reproducing well on the Apostle Islands.


Northern Wet-mesic Forest Photos

Northern Wet-mesic Forest Photo

White cedar swamp, Manitowoc County.

Photo by Andy Clark.

Northern Wet-mesic Forest Photo

White cedar swamps are rare in southern Wisconsin. In the SE Glacial Plains, they occur at a few sites along the eastern edge of the EL. Headwaters of Nichols Creek.

Photo by Christina Isenring.

Northern Wet-mesic Forest Photo

Old-growth northern wet-mesic forest (cedar swamp) in Forest County.

Photo by Ryan O'Connor.

Note: photos are provided to illustrate various examples of natural community types. A single photograph cannot represent the range of variability inherent in a given community type. Some of these photos explicitly illustrate unusual and distinctive community variants. The community photo galleries are a work in progress that we will expand and improve in the future.

Last revised: Wednesday, June 16, 2021