Key to the Natural Community Types

Photo by Joshua G. Cohen

The dichotomous key of natural community types includes a series of paired statements or couplets representing mutually exclusive choices. By progressively following these couplets, users will arrive at a natural community type. The key was developed as a tool to help users identify natural communities in the field but is also useful for learning about the critical factors that distinguish the natural community types.

Before using the keys in the field, first take time to study the site you would like to classify and walk as much of the area of interest as possible. Think about where you are in the landscape (e.g., upland vs. wetland, outwash plain vs. lakeplain, etc.) and determine the dominant vegetation structure and composition as well as the soils and critical natural processes that influence the area. When utilizing the key in the field, avoid ecotones or transition zones, and be mindful that natural communities are constantly changing in space and time. Sites that are shifting from one type to another through succession, or following a natural disturbance such as windthrow, beaver flooding, or fire can be especially difficult to classify. It is also critical to remember that the scale of consideration can influence how a site is classified. Natural community types are typically less than 100 acres, but several matrix-forming natural community types can be hundreds to thousands of acres and can occur as landscape complexes (e.g., wooded dune and swale complex, floodplain forest, patterned fen, muskeg, and mesic northern forest). These landscape complexes often contain diverse ecological zones that can also be interpreted as inclusions of natural community types.

The keys are intended as an aid in pointing the users in the right direction but are not meant to be used alone to definitively classify natural community types. Once you have worked your way through the key, we encourage you to examine the photos and description for the possible natural community type to help confirm your identification.


Class Key

  • IA. Palustrine (wetland) or terrestrial (upland) community or a relatively equal mixture of both. Characterized by soil developmentGo to IIA or IIB
    • IIA. Palustrine (wetland) or terrestrial (upland) communityGo to IIIA or IIIB
      • IIIA. Wetland soils and vegetation prevalent. Uplands absent or limited in extent to occasional islands and peninsulasPalustrine Class
      • IIIB. Upland soils and vegetation prevalent. Wetlands absent or limited in extent to occasional pockets and vernal poolsTerrestrial Class
    • IIB. Relatively equal mixture of palustrine and terrestrial communities occurring as a landscape complexPalustrine/Terrestrial Class
  • IB. Primary substrate prevalent. Characterized by little to no soil developmentGo to IVA or IVB
    • IVA. Surface feature that occurs on bedrock, cobble, and exposed mineral soilPrimary Class
    • IVB. Subterranean or sink feature located in areas of karst topography primarily along the Niagaran Cuesta in the eastern Upper Peninsula and northeastern Lower PeninsulaSubterranean/Sink Class

Palustrine Class Key

  • 1A. Open (non-forested) wetland. Mature trees absent or contributing 25% or less overall canopy cover and/or tall shrubs (>1.5m [5ft]) absent or contributing 50% or less canopy coverGo to 2A or 2B
    • 2A. Dominated by submergent vegetation and/or emergent graminoid vegetation with inundated to saturated organic or mineral soils or dominated by grasses, with sedges important but generally not dominant or locally dominant and seasonally inundated to saturated mineral soils with variable organic contentGo to 3A or 3B
      • 3A. Dominated by submergent vegetation and/or emergent graminoid vegetation with inundated to saturated soilsGo to 4A or 4B [Marsh Group]
        • 4A. Standing water greater than 15cm (6 in) deep usually present throughout the growing seasonGo to 5A or 5B
          • 5A. Occurrence not limited to shorelines of the Great Lakes and areas strongly influenced by Great Lakes water-level fluctuation and features such as connecting channels and river mouthsGo to 6A or 6B
            • 6A. Vegetation primarily submergent with leaves submerged or with leaves primarily submergent or floating on water surface during growing season. Occurring within shallow to occasionally deep waters of lakes, ponds, rivers, and streams. Common submergent and floating-leaved plants include common waterweed (Elodea canadensis), water star-grass (Heteranthera dubia), water-milfoils (Myriophyllum spp.), naiads (Najas spp.), pondweeds (Potamogeton spp.), water-celery (Vallisneria americana), muskgrasses (Chara spp.), stoneworts (Nitella spp.), coontail (Ceratophyllum demersum), bladderworts (Utricularia spp.), sweet-scented waterlily (Nymphaea odorata), yellow pond-lilies (Nuphar spp.), and water shield (Brasenia schreberi)Submergent Marsh
            • 6B. Vegetation primarily emergent with leaves protruding above the water (when present) during growing season. Occurring along the shores of lakes and streams or in depressions where standing water occurs throughout the year. Common emergent plants include bulrushes (Schoenoplectus spp.), sedges (Carex spp.), bur-reed (Sparganium spp.), water-plantain (Alisma spp.), spike-rushes (Eleocharis spp.), and broad leaved cat-tail (Typha latifolia)Emergent Marsh
          • 5B. Occurrence limited to shorelines of the Great Lakes and areas strongly influenced by Great Lakes water-level fluctuation including connecting channels and river mouthsGreat Lakes Marsh
        • 4B. Standing water absent or intermittently present seasonally and/or from year to year and typically less than 15cm (6 in) deep during mid-summer and early fall, but soil usually remaining saturated throughout the yearGo to 7A or 7B
          • 7A. Soil saturated to inundated by sodium- and chloride-laden groundwater from natural brine aquifers. Indicator plants include Olney’s bulrush (Schoenoplectus americanus) and dwarf spike-rush (Eleocharis parvula)Inland Salt Marsh
          • 7B. Soil saturated to inundated but not by sodium- and chloride-laden groundwater from natural brine aquifersGo to 8A or 8B
            • 8A. Occurrence not limited to shorelines of the Great Lakes and areas strongly influenced by Great Lakes water-level fluctuation and features such as dune fieldsGo to 9A or 9B
              • 9A. Characterized by large water-table fluctuations (both seasonally and from year to year) with mineral soils and organics ranging from inundated to saturatedGo to 10A or 10B
                • 10A. Occupies perimeters or entire basins of softwater seepage lakes and other isolated depressions characterized by large water-table fluctuations (both seasonally and from year to year). Soils mineral or occasionally shallow muck (< 1 m [39 in]) over sand or loamy sand with underlying clay lenses occasionally present. Atlantic and Gulf coastal plain disjunct plants common to locally dominant. Prevalent coastal plain disjuncts include black-fruited spike-rush (Eleocharis melanocarpa), round-headed rush (Juncus scirpoides), Eaton’s panic grass (Dichanthelium spretum), bald-rush (Rhynchospora scirpoides), bog yellow-eyed-grass (Xyris difformis), and meadow beauty (Rhexia virginica)Coastal Plain Marsh
                • 10B. Occupies perimeters or entire basins of softwater seepage lakes and other isolated depressions characterized by large water-table fluctuations (both seasonally and from year to year). Soils mineral or occasionally shallow muck (< 1 m [39 in]) over sand or loamy sand with underlying clay lenses occasionally present. Atlantic and Gulf coastal plain disjunct plants absent, rare, or limited in numberIntermittent Wetland
              • 9B. Characterized by relatively stable water table during the growing season with mineral soils and organics ranging from inundated in the spring to predominantly saturated throughout the growing seasonGo to 11A or 11B
                • 11A. Located north of the climatic tension zone in northern Lower Michigan and also in the Upper Peninsula. Vegetation dominated by sedges (Carex stricta, C. lacustris, C. lasiocarpa, C. utriculata, and/or C. vesicaria). Other important species include blue-joint (Calamagrostis canadensis), fringed brome (Bromus ciliatus), rattlesnake grass (Glyceria canadensis), marsh wild-timothy (Muhlenbergia glomerata), and green bulrush (Scirpus atrovirens). Soils are typically strongly acidic to neutral, shallow to deep peat, but can include saturated mineral soil. Frequently invaded by tag alder (Alnus incana) and occurring in association with northern shrub thicketNorthern Wet Meadow
                • 11B. Located south of the climatic tension zone in southern Lower Michigan. Vegetation dominated by tussock sedge (Carex stricta) and sometimes by wiregrass sedge (C. lasiocarpa) and lake sedge (C. lacustris). Other important species include blue-joint (Calamagrostis canadensis), sedges (Carex aquatilis, C. comosa, C. prairea, C. utriculata), fringed brome (Bromus ciliatus), marsh wild-timothy (Muhlenbergia glomerata), joe-pye-weed (Eutrochium maculatum), and common boneset (Eupatorium perfoliatum). Soils are typically neutral to mildly alkaline peats. Frequently invaded by dogwoods (Cornus spp.), willows (Salix spp.), and meadowsweet (Spiraea alba) and occurring in association with southern shrub-carrSouthern Wet Meadow
            • 8B. Occurrence limited to shorelines of the Great Lakes and areas strongly influenced by Great Lakes water-level fluctuation and features such as dune fieldsInterdunal Wetland
      • 3B. Dominated by grasses, with sedges important to locally dominant and seasonally inundated to saturated soilsGo to 12A or 12B [Wet Prairie Group]
        • 12A. Occurring inland on outwash plains, old glacial lakebeds, abandoned stream channels, and river terraces. Distribution not limited to glacial lakeplain in southeastern or southwestern Lower MichiganGo to 13A or 13B
          • 13A. Soils loam to silt loam often with high organic content. Occurring in southern Lower MichiganGo to 14A or 14B
            • 14A. Seasonally inundated soils. Dominant grasses include blue-joint (Calamagrostis canadensis)and cordgrass (Spartina pectinata), with tussock sedge (Carex stricta) locally dominantWet Prairie
            • 14B. Occasionally inundated soils. Dominant grasses include big bluestem (Andropogon gerardii) and Indian grass (Sorghastrum nutans), with blue-joint (Calamagrostis canadensis), cordgrass (Spartina pectinata), and tussock sedge (Carex stricta) locally commonWet-mesic Prairie
          • 13B. Soils sand to sandy loam often with high organic content. Occurring in both northern and southern Lower Michigan. Dominant grasses may include big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium), Indian grass (Sorghastrum nutans), blue-joint (Calamagrostis canadensis), cordgrass (Spartina pectinata), and prairie dropseed (Sporobolus heterolepis). Tussock sedge (Carex stricta) may be locally dominantWet-mesic Sand Prairie
        • 12B. Occurring on lakeplains both along Great Lakes shoreline and inland. Distribution limited to glacial lakeplain in southeastern or southwestern Lower MichiganGo to 15A or 15B
          • 15A. Vegetation dominated by bluejoint grass (Calamagrostis canadensis) and cordgrass (Spartina pectinata). Common species typically include sedges (Carex aquatilis,C.buxbaumii, C. pellita, C.prairea, C. stricta), Baltic rush (Juncus balticus), twig-rush (Cladium mariscoides), and swamp milkweed (Asclepias incarnata)Lakeplain Wet Prairie
          • 15B. Vegetation dominated by big bluestem (Andropogon gerardii), switch grass (Panicum virgatum), little bluestem (Schizachyrium scoparium), and/or Indian grass (Sorghastrum nutans). Common species typically include sedges (Carex spp.), Ohio goldenrod (Solidago ohioensis), Riddell’s goldenrod (Solidago riddellii), common mountain mint (Pycnanthemum virginianum), swamp-betony (Pedicularis lanceolata), marsh blazing-star (Liatris spicata), colic root (Aletris farinosa), tall coreopsis (Coreopsis tripteris), and ironweed (Vernonia spp.)Lakeplain Wet-mesic Prairie
    • 2B. Dominated by graminoids and forbs with low shrubs, stunted conifers, and brown mosses or sphagnum mosses often prevalent. Characterized almost exclusively by saturated organic soils (peat or marl)Go to 16A or 16B
      • 16A. Minerotrophic or mineral-rich peatland with slightly acidic to alkaline saturated peats or marl or slightly minerotrophic peatland with strongly acidic to slightly acidic saturated peats. Sphagnum mosses are absent or locally common to dominantGo to 17A or 17B [Fen Group]
        • 17A. Slightly minerotrophic peatland with strongly acidic to slightly acidic saturated peatsGo to 18A or 18B
          • 18A. Community structure lacks repeating pattern of low peat rises (strings) and alternating hollows (flarks). Vegetation dominated by few-seed sedge (Carex oligosperma) and/or wiregrass sedge (C. lasiocarpa), often with sphagnum either throughout ground layer or dominating widely scattered, low peat mounds, along with ericaceous shrubs and stunted conifersPoor Fen
          • 18B. Community structure characterized by a repeated, alternating pattern of low peat rises (strings) and hollows (flarks). Strings may support scattered and stunted black spruce (Picea mariana) and tamarack (Larix laricina), low shrubs including bog birch (Betula pumila), shrubby cinquefoil (Dasiphora fruticosa), bog rosemary (Andromeda glaucophylla), leatherleaf (Chamaedaphne calyculata), sedges (Carex oligosperma,C. sterilis, and C. lasiocarpa), and tufted bulrush (Trichophorum cespitosum). The alternating flarks are seasonally inundated and may support open lawns of mosses, sedges (Carex lasiocarpa, C. limosa, C. livida, C. oligosperma, and C. exilis), common bog arrow-grass (Triglochin maritima), bog buckbean (Menyanthes trifoliata), and arrow-grass (Scheuchzeria palustris)Patterned Fen
        • 17B. Minerotrophic or mineral-rich peatland with slightly acidic to alkaline saturated peats or marlGo to 19A or 19B
          • 19A. Community structure characterized by a repeated, alternating pattern of low peat rises (strings) and hollows (flarks). Strings may support scattered and stunted northern white-cedar (Thuja occidentalis), tamarack (Larix laricina), and black spruce (Picea mariana); low shrubs including bog birch (Betula pumila), shrubby cinquefoil (Dasiphora fruticosa), bog rosemary (Andromeda glaucophylla), and leatherleaf (Chamaedaphne calyculata); tufted bulrush (Trichophorum cespitosum); and sedges (Carex lasiocarpa,C. sterilis, and C. oligosperma). The alternating flarks are seasonally inundated and may support open lawns of mosses, sedges (Carex lasiocarpa, C. limosa, C. livida, and C. exilis), common bog arrow-grass (Triglochin maritima), bog buckbean (Menyanthes trifoliata), and arrow-grass (Scheuchzeria palustris)Patterned Fen
          • 19B. Community structure lacks repeating pattern of low peat rises (strings) and alternating hollows (flarks)Go to 20A or 20B
            • 20A. Occurrence not limited to shorelines of the Great Lakes and areas strongly influenced by Great Lakes water-level fluctuation and processes. Dominance shared by sedges, grasses, rushes, bulrushes, and forbs. Scattered conifers and shrubs common. Soils neutral to moderately alkaline deep peat or marl. Vegetation sparse where marl covers the surface. Vegetation zonation well developed and strongly influenced by surface and subsurface groundwater seepage. Calciphiles well represented, including Kalm’s lobelia (Lobelia kalmii), Ohio goldenrod (Solidago ohioensis), bog goldenrod (S. uliginosa), false asphodel (Triantha glutinosa), grass-of-Parnassus (Parnassia glauca), beak-rush (Rhynchospora capillacea), common bog arrow-grass (Triglochin maritima), twig-rush (Cladium mariscoides), rush (Juncus brachycephalus), golden-seeded spike-rush (Eleocharis elliptica), beaked spike-rush (Eleocharis rostellata), white camas (Anticlea elegans), shrubby cinquefoil (Dasiphora fruticosa), and alder-leaved buckthorn (Rhamnus alnifolia)Go to 21A or 21B
              • 21A. Located north of the climatic tension zone in northern Lower Michigan and the Upper Peninsula. Additional common species include sedges (Carex lasiocarpa, C. chordorrhiza, C. leptalea, C. limosa, C. livida, and C. sterilis), tufted bulrush (Trichophorum cespitosum), bog birch (Betula pumila), northern white-cedar (Thuja occidentalis), and tamarack (Larix laricina)Northern Fen
              • 21B. Located south of the climatic tension zone in southern Lower Michigan, primarily in interlobate regions. Additional common species include sedges (Carex stricta, C. sterilis, C. lasiocarpa, C. buxbaumii, C. prairea,C. leptalea, C. interior, and C. tetanica), big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium), Indian grass (Sorghastrum nutans), flat-topped white aster (Doellingeria umbellata), whorled loosestrife (Lysimachia quadriflora), common mountain mint (Pycnanthemum virginianum), Riddell’s goldenrod (Solidago riddellii), sage willow (Salix candida), poison sumac (Toxicodendron vernix), and tamarack (Larix laricina)Prairie Fen
            • 20B. Occurrence limited to shorelines of the Great Lakes and areas strongly influenced by Great Lakes water-level fluctuation and processes. Located in protected bays and abandoned coastal embayments along the shorelines of northern Lake Huron and Lake Michigan. Soils grade from calcareous sand or clay along shoreline to alkaline marl and organic deposits farther inland. Vegetation comprised of sedges, rushes, and calciphiles including spike-rushes (Eleocharis elliptica and E.rostellata), false asphodel (Triantha glutinosa), limestone calamint (Clinopodium arkansanum), Kalm’s lobelia (Lobelia kalmii), grass-of-Parnassus (Parnassia glauca), Indian paintbrush (Castilleja coccinea), bird’s-eye primrose (Primula mistassinica), small fringed gentian (Gentianopsis virgata), white camas (Anticlea elegans), and shrubby cinquefoil (Dasiphora fruticosa)Coastal Fen
      • 16B. Ombrotophic or nutrient-poor peatland with extremely acidic to strongly acidic saturated peats. Ground layer dominated by continuous carpet of sphagnum mossesGo to 22A or 22B [Bog Group]
        • 22A. Trees absent or occurring in localized areas of peatland with overall canopy cover typically less than 10%. Occurring statewide but uncommon in southern Lower MichiganBog
        • 22B. Tree canopy cover typically 10 to 25%, consisting of scattered and stunted black spruce (Picea mariana) and tamarack (Larix laricina) with pines (Pinus spp.) locally common. Occurring north of the climatic tension zone, predominantly in the Upper Peninsula and less frequently in northern Lower MichiganMuskeg
  • 1B. Forested or tall shrub-dominated wetland. Mature trees contributing greater than 25% overall canopy cover and/or tall shrubs (> 1.5m [5ft]) contributing more than 50% canopy coverGo to 23A or 23B
    • 23A. Mature trees contributing 25% or less overall canopy cover. Tall shrubs (> 1.5 m [5 ft]) dominant, contributing greater than 50% overall canopy coverGo to 24A or 24B [Shrub Wetland Group]
      • 24A. Dominated by buttonbush (Cephalanthus occidentalis). Typically occurring in small, isolated depressions south of the climatic tension zone in southern Lower Michigan. Standing water often present throughout growing seasonInundated Shrub Swamp
      • 24B. Dominated by shrub species other than buttonbush (Cephalanthus occidentalis)Go to 25A or 25B
        • 25A. Shrub canopy dominated by tag alder (Alnus incana). Occurring predominantly north of the climatic tension zone in northern Lower Michigan and the Upper Peninsula along streams and lake edges, on outwash channels, outwash plains, and lakeplains.Northern Shrub Thicket
        • 25B. Shrub canopy dominated by dogwoods (Cornus sericea, C. amomum, and C. foemina) and willows (Salix bebbiana, S. discolor, S. exigua, and S. petiolaris). Occurring predominantly south of the climatic tension zone in southern Lower Michigan on outwash channels, outwash plains, and lakeplainsSouthern Shrub-Carr
    • 23B. Mature trees contributing greater than 25% overall canopy coverGo to 26A or 26B [Forested Wetland Group]
      • 26A. Conifers important, common to dominant in canopy layerGo to 27A or 27B
        • 27A. Conifers overwhelmingly dominantGo to 28A or 28B
          • 28A. Ombrotophic or nutrient-poor peatland. Canopy strongly dominated by black spruce (Picea mariana), frequently with tamarack (Larix laricina), and occasionally with jack pine (Pinus banksiana) as codominants. Substrate extremely acidic to very strongly acidic, deep fibric peat. Sphagnum mosses dominant in ground layer. Ericaceous shrubs including leatherleaf (Chamaedaphne calyculata), Labrador-tea (Rhododendron groenlandicum), bog laurel (Kalmia polifolia), and, in southern Lower Michigan, smooth highbush blueberry (Vaccinium corymbosum) locally abundant to dominant. Hydrology strongly influenced by precipitation due to peat accumulation above groundwater table. Occurring mostly north of the climatic tension zone in depressions of glacial outwash, glacial lakeplains, ground moraine, and kettles in coarse-textured moraines and ice-contact topographyPoor Conifer Swamp
          • 28B. Minerotrophic or mineral-rich peatland. Canopy strongly dominated by northern white-cedar (Thuja occidentalis) or tamarack (Larix laricina)Go to 29A or 29B
            • 29A. Occurring primarily north of the climatic tension zone in northern Lower Michigan and the Upper Peninsula and rarely in southern Lower Michigan. Canopy strongly dominated by northern white-cedar (Thuja occidentalis). Tall shrub layer typically sparse but can be well-developed with tag alder (Alnus incana). Substrate very strongly acidic to moderately alkaline, with subsurface peat typically circumneutral to moderately alkaline. Hydrology strongly influenced by groundwater movementRich Conifer Swamp
            • 29B. Occurring primarily south of the climatic tension zone in southern Lower Michigan and occasionally in northern Lower Michigan and the Upper Peninsula. Canopy strongly dominated by tamarack (Larix laricina). Tall shrub layer typically well developed, with winterberry (Ilex verticillata) and/or poison sumac (Toxicodendron vernix) common to abundant. Substrate neutral to moderately alkaline, deep peat (> 1 m [39 in]). Hydrology strongly influenced by groundwater movementRich Tamarack Swamp
        • 27B. Conifers codominant or subdominant to hardwoodsGo to 30A or 30B
          • 30A. Occurring along headwater streams (1st and 2nd orders), and on poorly drained glacial outwash, lakeplain, and morainesGo to 31A or 31B
            • 31A. Tamarack (Larix laricina) dominant. Canopy associates include white pine (Pinus strobus), black ash (Fraxinus nigra), yellow birch (Betula alleghaniensis), red maple (Acer rubrum), swamp white oak (Quercus bicolor), and American elm (Ulmus americana). Substrate neutral to moderately alkaline, deep peat (> 1 m [39 in]). Tall shrub layer typically well developed with winterberry (Ilex verticillata) and/or poison sumac (Toxicodendron vernix) common to abundant. Hydrology strongly influenced by groundwater movement. Occurring primarily south of the climatic tension zone in southern Lower Michigan and occasionally in northern Lower Michigan and the Upper Peninsula. In interlobate regions, is often associated with prairie fenRich Tamarack Swamp
            • 31B. Tamarack (Larix laricina) occasional to absent. Overall canopy comprised of a mixture of hardwood and conifer species, but either group may be locally dominant. Common trees include yellow birch (Betula alleghaniensis), black ash (Fraxinus nigra), red maple (Acer rubrum), American elm (Ulmus americana), hemlock (Tsuga canadensis), northern white-cedar (Thuja occidentalis), white pine (Pinus strobus), and tamarack. Substrate neutral to strongly acidic, deep to shallow peat or poorly drained mineral soils. Tall shrub layer poorly developed. Hydrology influenced by groundwater movement. Occurring statewideHardwood-Conifer Swamp
          • 30B. Occurring in floodplains of 3rd order or greater streams and rivers and characterized by fluvial landforms, such as natural levee, first bottom, backswamp, oxbow, and terrace. Typically dominated by hardwoods such as silver maple (Acer saccharinum) and green ash (Fraxinus pennsylvanica). Where organic soils accumulate in areas of groundwater seepage, backswamps, and meander scars, conifers [tamarack (Larix laricina), hemlock (Tsuga canadensis), northern white-cedar (Thuja occidentalis), and white pine (Pinus strobus)] can be important, especially north of the climatic tension zoneFloodplain Forest
      • 26B. Conifers absent or rare in canopy layer. Hardwoods dominant throughoutGo to 32A or 32B
        • 32A. Occurring in floodplains of 3rd order or greater streams and rivers and characterized by fluvial landforms, such as natural levee, first bottom, backswamp, oxbow, and terrace. Dominant overstory species include silver maple (Acer saccharinum), green ash (Fraxinus pennsylvanica), cottonwood (Populus deltoides), swamp white oak (Quercus bicolor), bur oak (Quercus macrocarpa), bitternut hickory (Carya cordiformis), sycamore (Platanus occidentalis), and hackberry (Celtis occidentalis). Where organic soil accumulates in areas such as groundwater seepages, backswamps, and meander scars, tree species may include black ash (Fraxinus nigra), yellow birch (Betula alleghaniensis), and red maple (Acer rubrum)Floodplain Forest
        • 32B. Occurring along headwater streams (1st and 2nd orders), and on poorly drained glacial outwash, lakeplain, and/or depressions in moraines or ice-contact topographyGo to 33A or 33B
          • 33A. Distributed north of the climatic tension zone in northern Lower Michigan and the Upper Peninsula. Canopy dominated by black ash (Fraxinus nigra) with lesser importance of red maple (Acer rubrum), American elm (Ulmus americana), yellow birch (Betula alleghaniensis), green ash (Fraxinus pennsylvanica), balsam fir (Abies balsamea), and northern white-cedar (Thuja occidentalis). Soils are slightly acidic to neutral, hydric mineral soils and shallow muck over mineral soils. Occurring on poorly drained lakeplains, outwash plains, and fine- to medium-textured glacial tillNorthern Hardwood Swamp
          • 33B. Distributed south of the climatic tension zone in southern Lower MichiganGo to 34A or 34B
            • 34A. Located in depressions on glacial outwash, moraines, and lakeplain throughout southern Lower Michigan. Dominant tree species comprised of lowland hardwoods including silver maple (Acer saccharinum), red maple (A. rubrum), green ash (Fraxinus pennsylvanica), black ash (F. nigra), swamp white oak (Quercus bicolor), bur oak (Q.macrocarpa), and occasionally pin oak (Q.palustris). Mineral and organic soils are typically circumneutralSouthern Hardwood Swamp
            • 34B. Located almost exclusively on level lakeplain in southeastern Lower Michigan. Dominant tree species comprised of highly diverse mixture of lowland and upland hardwoods including oaks (Quercus spp.), hickories (Carya spp.), maples (Acer spp.), and ashes (Fraxinus spp.). Soils typically slightly to medium acidic sandy loam or loam over mildly alkaline sandy clay loam, clay loam, or clay. An underlying impermeable clay lens is often present, which allows for prolonged pooling of water. Can occur as a mosaic of poorly drained areas and upland islandsWet-mesic Flatwoods

Terrestrial Class Key

  • 1A. Mature trees absent or canopy cover less than 5% with generally less than one tree per acreGo to 2A or 2B [Prairie Group]
    • 2A. Native grass, sedge, and forb community occurring along steep slopes of outwash channels and moraines with south- to west-facing slopes associated with river valleys, streams, or kettle lakes and surrounded by oak forest or oak savannaHillside Prairie
    • 2B. Native grass, sedge, and forb community occurring on rolling moraines, level to undulating outwash plains, and flat lakeplainsGo to 3A or 3B
      • 3A. Late summer vegetation generally short (<1.0 m [39 in]) and patchy. Dominant plants include little bluestem (Schizachyrium scoparium), Pennsylvania sedge (Carex pensylvanica), and scattered patches of big bluestem (Andropogon gerardii). Occurring on loamy sands on well-drained to excessively well-drained, sandy glacial outwash plains and lakebeds primarily north of the climatic tension zone in the north-central and western Lower Peninsula and occasionally in southern Lower Michigan. Often associated with oak barrens, oak-pine barrens, or pine barrensDry Sand Prairie
      • 3B. Late summer vegetation generally tall (>1.0 m [39 in]) and dense. Dominant plants include big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium), and Indian grass (Sorghastrum nutans)Go to 4A or 4B
        • 4A. Comprised of upland prairie species. Restricted to southern Lower Michigan. Upper layer of soils do not show evidence of a fluctuating water tableGo to 5A or 5B
          • 5A. Soils loamy sand, sand, or occasionally sandy loams, dark brown to tan in color. Characteristic species include Pennsylvania sedge (Carex pensylvanica), bastard-toadflax (Comandra umbellata), leadplant (Amorpha canescens), thimbleweed (Anemone cylindrica), black-eyed Susan (Rudbeckia hirta), round-headed bush-clover (Lespedeza capitata), butterfly-weed (Asclepias tuberosa), and smooth aster (Symphyotrichum laeve). Occurring on both outwash and moraines within range of former oak openings in southern Lower Michigan but most prevalent in southwestern Lower MichiganDry-mesic Prairie
          • 5B. Soils loam or occasionally sandy loam, black to dark brown in color. Cordgrass (Spartina pectinata) occasionally subdominant. Other characteristic herbs include porcupine grass (Hesperostipa spartea), prairie dropseed (Sporobolus heterolepis), switch grass (Panicum virgatum), rattlesnake-master (Eryngium yuccifolium), golden alexanders (Zizia aurea), and prairie violet (Viola pedatifida). Occurring on level to slightly undulating glacial outwash in southwestern Lower MichiganMesic Prairie
        • 4B. Comprised predominantly of upland prairie species, but also includes species more commonly associated with wetlands, including blue-joint (Calamagrostis canadensis), rushes (Juncus spp.), flat-topped white aster (Doellingeria umbellata), balsam ragwort (Packera paupercula), and common mountain mint (Pycnanthemum virginianum). Occurring on lakeplains (especially on old beach ridges elevated above poorly drained lakeplains), outwash, old glacial lakebeds, abandoned stream channels, and river terraces throughout the Lower Peninsula. Soils sandy loam to loamy sand, occasionally showing evidence of a fluctuating water table such as iron mottlingMesic Sand Prairie
  • 1B. Mature trees present at densities greater than one tree per acre and canopy cover ranging from 5 to 100%Go to 6A or 6B
    • 6A. Tree canopy cover less than 60% with ground flora primarily native grasses, sedges, forbs, and low shrubs associated with open- or partial-canopy conditionsGo to 7A or 7B [Savanna Group]
      • 7A. Mature trees pines (Pinus spp.) or mixture of pine and oak (Quercus spp.) speciesGo to 8A or 8B
        • 8A. Scattered jack pine (Pinus banksiana) or jack pine thickets among native graminoids. Ground layer dominated by Pennsylvania sedge (Carex pensylvanica), or Pennsylvania sedge, little bluestem (Schizachyrium scoparium), big bluestem (Andropogon gerardii), forbs, and low shrubs. Occurring in northern Michigan on excessively drained, sandy outwash plains and lakeplainsPine Barrens
        • 8B. Scattered and clumped oak and pine species with ground flora of native grassland species. Mature tree species may include white oak (Quercus alba), northern pin oak (Q. ellipsoidalis), black oak (Q. velutina), white pine (Pinus strobus), red pine (P. resinosa), and jack pine (P. banksiana). Ground layer dominated by little bluestem (Schizachyrium scoparium), Pennsylvania sedge (Carex pensylvanica), big bluestem (Andropogon gerardii), forbs, and low shrubs. Occurring both north and south of the climatic tension zone on sandy outwash plains, lakeplains, and occasionally coarse-textured end morainesOak-Pine Barrens
      • 7B. Mature trees oaks (Quercus spp.) with little to no pine (Pinus spp.). Located south of the climatic tension zone in southern Lower MichiganGo to 9A or 9B
        • 9A. Scattered white oak (Quercus alba) or mixed oak species among tall and short prairie grassesGo to 10A or 10B
          • 10A. Savanna community occurring on moraines and outwash areas primarily within southern Lower MichiganGo to 11A or 11B
            • 11A. Scattered black oak (Quercus velutina), white oak (Q. alba), and occasionally northern pin oak (Q. ellipsoidalis) among prairie grasses occurring on infertile, droughty soils on glacial outwash and south- to west-facing, steep, coarse-textured moraines. Characteristic shrubs and forbs include American hazelnut (Corylus americana), New Jersey tea (Ceanothus americanus), serviceberries (Amelanchier spp.), bearberry (Arctostaphylos uva-ursi), sweetfern (Comptonia peregrina), blue toadflax (Nuttallanthus canadensis), prickly-pear (Opuntia humifusa), jointweed (Polygonella articulata), wild lupine (Lupinus perennis), dwarf dandelion (Krigia virginica), hairy puccoon (Lithospermum caroliniense), and birdfoot violet (Viola pedata)Oak Barrens
            • 11B. Scattered white oak (Quercus alba), bur oak (Q. macrocarpa), and chinquapin oak (Q.muehlenbergii), with occasional pignut hickory (Carya glabra), shagbark hickory (C. ovata), red oak (Q. rubra), and black oak (Q. velutina) among prairie grasses and a mix of prairie and forest ground flora. Prevalent fire-tolerant shrubs include American hazelnut (Corylus americana), New Jersey tea (Ceanothus americanus), and leadplant (Amorpha canescens), and characteristic forbs include milkweeds (Asclepias spp.), prairie coreopsis (Coreopsis palmata), yellow coneflower (Ratibida pinnata), Culver’s root (Veronicastrum virginicum), and tick-trefoils (Desmodium spp.). Nearly completely extirpated from Michigan but once prevalent in the southern Lower Peninsula on moderately fertile sandy loams and loamy sands of outwash and coarse-textured morainesOak Openings
          • 10B. Savanna community occurring on sand ridges, level sandplains, and depressions within lakeplains of southeastern Lower Michigan and Saginaw Bay. Soils are very fine-textured sandy loams, loamy sands, or sands. Dominant tree species include white oak (Quercus alba) and black oak (Q. velutina) on well-drained soils, and bur oak (Q. macrocarpa), pin oak (Q.palustris), and swamp white oak (Q.bicolor) in poorly drained depressionsLakeplain Oak Openings
        • 9B. Scattered bur oak (Quercus macrocarpa) among tall prairie grasses occurring historically in southwestern Lower Peninsula on outwash plains and river terraces but now believed extirpated from Michigan. Soils fertile, fine-textured loam, sandy loam, or silt loamBur Oak Plains
    • 6B. Tree canopy cover 60% or more with ground flora primarily native forbs, sedges, and grasses associated with closed-canopy conditionsGo to 12A or 12B [Forest Group]
      • 12A. Forested community primarily occurring north of the climatic tension zone in northern Lower Michigan and the Upper PeninsulaGo to 13A or 13B
        • 13A. Overstory dominated by pines (Pinus spp.) and/or sugar maple (Acer saccharum), American beech (Fagus grandifolia), basswood (Tilia americana), hemlock (Tsuga canadensis), and yellow birch (Betula alleghaniensis)Go to 14A or 14B
          • 14A. Overstory dominated by pines (Pinus spp.) and/or mixture of pine and oakGo to 15A or 15B
            • 15A. Overstory dominated by jack pine (Pinus banksiana) or red pine (P. resinosa), or jack pine and northern pin oak (Quercus ellipsoidalis). Soils droughty, low-nutrient, extremely acidic to very strongly acidic sands. Occurring on sandy glacial outwash, sandy glacial lakeplains, and sand ridges within peatlandsDry Northern Forest
            • 15B. Overstory dominated or codominated by white pine (Pinus strobus), often with red pine (P. resinosa), white oak (Quercus alba), black oak (Q. velutina), red oak (Q. rubra), and/or hemlock (Tsuga canadensis). Soils extremely acidic to very strongly acidic sand or loamy sand. Occurring on sandy glacial outwash, sandy glacial lakeplains, and less often on thin glacial drift over bedrock, inland dune ridges, and coarse-textured morainesDry-mesic Northern Forest
          • 14B. Overstory dominated by sugar maple (Acer saccharum), hemlock (Tsuga canadensis), American beech (Fagus grandifolia), basswood (Tilia americana), white pine (Pinus strobus), and/or yellow birch (Betula alleghaniensis)Mesic Northern Forest
        • 13B. Overstory dominated by northern white-cedar (Thuja occidentalis), white spruce (Picea glauca), and balsam fir (Abies balsamea). Occurring primarily along northern shorelines of the Great Lakes, on Great Lakes islands, and locally inlandBoreal Forest
      • 12B. Forested community primarily occurring south of the climatic tension zone in southern Lower MichiganGo to 16A or 16B
        • 16A. Overstory dominated by oaksGo to 17A or 17B
          • 17A. Soils droughty, infertile, strongly to medium acidic sand, loamy sand, or sandy loam. Occurring principally on glacial outwash, and less frequently on sand dunes, sandy glacial lakeplains, and coarse-textured moraines. Overstory dominated by black oak (Quercus velutina) and/or white oak (Q.alba) with canopy associates including pignut hickory (Carya glabra), sassafras (Sassafras albidum), black cherry (Prunus serotina), and/or northern pin oak (Q.ellipsoidalis)Dry Southern Forest
          • 17B. Soils dry-mesic, moderately fertile, slightly acidic to neutral sandy loam or loam. Occurring on glacial outwash, coarse-textured moraines, sandy glacial lakeplains, and occasionally kettle-kame topography and sand dunes. Overstory dominated by white oak (Quercus alba), black oak (Q. velutina), and/or red oak (Q. rubra), often with abundant pignut hickory (Carya glabra), shagbark hickory (C. ovata), bitternut hickory (C.cordiformis), red maple (Acer rubrum), white ash (Fraxinus americana), black cherry (Prunus serotina), northern pin oak (Q.ellipsoidalis), basswood (Tilia americana), and/or sassafras (Sassafras albidum)Dry-mesic Southern Forest
        • 16B. Overstory dominated by sugar maple (Acer saccharum) and American beech (Fagus grandifolia), with abundant red oak (Quercus rubra), white ash (Fraxinus americana), and/or basswood (Tilia americana)Mesic Southern Forest

Palustrine/Terrestrial Class Key

  • 1. Relatively equal mixture of palustrine and terrestrial communities or zones occurring as a landscape complexGo to 2A or 2B
    • 2A. Restricted to the Great Lakes shoreline. Occurring north of the climatic tension zone in northern Lower Michigan and the Upper Peninsula. Characterized by repeated pattern of alternating dunes and swales and supporting a mixture of upland and wetland communitiesWooded Dune and Swale Complex [Wooded Dune and Swale Group]
    • 2B. Not restricted to the Great Lakes shoreline. Occurring throughout Michigan or restricted to lakeplains of southeastern Lower Michigan. Supporting a mixture of upland and wetland zonesGo to 3A or 3B
      • 3A. Occurring in floodplains of 3rd order or greater streams and rivers throughout Michigan. Characterized by fluvial landforms, such as natural levee, first bottom, backswamp, oxbow, and terrace, that support a diversity of upland and wetland zonesFloodplain Forest
      • 3B. Not occurring in floodplains of streams and rivers. Restricted to lakeplains of southeastern Lower Michigan. Characterized by sand ridges and depressions that support upland and wetland zonesLakeplain Oak Openings

Primary Class Key

  • 1A. Substrate primarily dune sands. Occurring in areas of extensive dune developmentGo to 2A or 2B [Dunes Group]
    • 2A. Vegetation primarily grasses and low shrubs with scattered trees. Characteristic vegetation includes marram grass (Ammophila breviligulata), sand reed grass (Calamovilfa longifolia), little bluestem (Schizachyrium scoparium), bearberry (Arctostaphylos uva-ursi), creeping juniper (Juniperus horizontalis), sand cherry (Prunus pumila), willows (Salix cordata and S. myricoides), and common juniper (Juniperus communis)Open Dunes
    • 2B. Vegetation primarily evergreen trees and shrubs with scattered or clumped pines (Pinus spp.), white spruce (Picea glauca), and northern white-cedar (Thuja occidentalis) over dense, low shrub cover dominated by common juniper (Juniperus communis), creeping juniper (J.horizontalis), bearberry (Arctostaphylos uva-ursi), and sand cherry (Prunus pumila), and patches of grasses, especially sand reed grass (Calamovilfa longifolia) and little bluestem (Schizachyrium scoparium). Occurring in dune fields and in depressions among dune ridgesGreat Lakes Barrens
  • 1B. Substrate primarily sand and gravel, cobble, bedrock, or clayGo to 3A or 3B
    • 3A. Substrate primarily sand and gravel or cobble. Located along Great Lakes shorelineGo to 4A or 4B [Sand/Cobble Shore Group]
      • 4A. Substrate sand and gravel. Very sparsely vegetated with forbs and grasses such as sea rocket (Cakile edentula), Baltic rush (Juncus balticus), silverweed (Potentilla anserina), and beach pea (Lathyrus japonicus)Sand and Gravel Beach
      • 4B. Substrate cobble. Very sparsely vegetatedGo to 5A or 5B
        • 5A. Located along northern Lakes Michigan and Huron. Cobble comprised chiefly of limestone and/or dolomiteLimestone Cobble Shore
        • 5B. Located primarily along Lake Superior. Comprised chiefly of sandstone or volcanic cobbleGo to 6A or 6B
    • 3B. Substrate primarily bedrock or steeply sloping bluffs of clay. Located along Great Lakes shoreline or inlandGo to 7A or 7B
      • 7A. Substrate level to gently sloping (slightly tilted) bedrock with trees absent to rareGo to 8A or 8B
        • 8A. Located along Great Lakes shorelineGo to 9A or 9B [Bedrock Lakeshore Group]
          • 9A. Located along northern Lakes Michigan and Huron on the Niagaran Cuesta in the eastern Upper Peninsula and locally in the northern Lower Peninsula. Sparse cover of native vegetation on limestone and/or dolomite bedrockLimestone Bedrock Lakeshore
          • 9B. Located along Lake Superior. Sparse cover of native vegetation on sandstone, granitic, volcanic, or metamorphic bedrockGo to 10A or 10B
            • 10A. Substrate primarily sandstone bedrockSandstone Bedrock Lakeshore
            • 10B. Substrate primarily volcanic or granitic bedrockGo to 11A or 11B
              • 11A. Substrate primarily granitic bedrock, which may include granite, quartzite, schist, gabbro, gneiss, and a diversity of other resistant igneous and metamorphic rock typesGranite Bedrock Lakeshore
              • 11B. Substrate primarily volcanic in origin including basalt and volcanic conglomerate bedrocksVolcanic Bedrock Lakeshore
        • 8B. Located inland from the Great Lakes shoreline and dominated by graminoids, including grasses, sedges, and spike-rushesAlvar [Bedrock Grassland Group]
      • 7B. Substrate level to steeply sloping bedrock with scattered canopy or sparsely vegetated community with vertical to near vertical exposures of bedrock or steeply sloping bluffs of clayGo to 12A or 12B
        • 12A. Substrate level to steeply sloping bedrock. Characterized by savanna community structure with scattered native trees and shrubsGo to 13A or 13B [Bedrock Glade Group]
          • 13A. Located primarily along the Niagaran Cuesta in the eastern Upper Peninsula and northeastern Lower Peninsula. Substrate primarily level to gently sloping, slightly tilted, or occasionally stair-stepped with thin soils over limestone and/or dolomite bedrockLimestone Bedrock Glade
          • 13B. Located primarily in the western Upper Peninsula. Substrate level to steep or stair-stepped with thin soils and areas of exposed granitic or volcanic bedrockGo to 14A or 14B
            • 14A. Substrate granitic bedrock, which may include granite, schist, gabbro, gneiss, slate, and a diversity of other resistant igneous and metamorphic rock types. Distributed primarily in northern Marquette CountyGranite Bedrock Glade
            • 14B. Substrate volcanic in origin including basalt and volcanic conglomerate bedrock. Distributed primarily in the Keweenaw Peninsula, Ontonagon County, and Gogebic CountyGo to 15A or 15B
              • 15A. Substrate level to steep or stair-stepped. Not positioned on the tops of high bedrock escarpmentsVolcanic Bedrock Glade
              • 15B. Substrate level to steeply sloping. Positioned on the tops of high bedrock escarpments. Low shrubs, flagged trees, and dwarfed, misshapen trees distorted into a krummholz growth form are commonNorthern Bald
        • 12B. Sparsely vegetated community with vertical to near vertical exposures of bedrock or steeply sloping bluffs of clayGo to 16A or 16B
          • 16A. Located along the Great Lakes shoreline or along rivers draining into the Great LakesGo to 17A or 17B [Lakeshore Cliff/Bluff Group]
            • 17A. Steep to near-vertical clay slopes along the shorelines of Lake Michigan and Lake Superior or along rivers draining into the Great LakesClay Bluffs
            • 17B. Vertical or nearly vertical exposure of bedrock along lakeshoreGo to 18A or 18B
              • 18A. Located primarily along northern Lakes Michigan and Huron on the Niagaran Escarpment in the eastern Upper Peninsula. Substrate limestone and/or dolomite bedrockLimestone Lakeshore Cliff
              • 18B. Located primarily along Lake Superior. Substrate sandstone, granitic, or volcanic bedrockGo to 19A or 19B
                • 19A. Located primarily along Lake Superior with rare occurrences along Lake Huron. Substrate primarily sandstone bedrockSandstone Lakeshore Cliff
                • 19B. Restricted to Lake Superior shoreline. Substrate granitic or volcanic bedrockGo to 20A or 20B
                  • 20A. Composed of granitic bedrock, which may include granite, quartzite, schist, gabbro, gneiss, and a diversity of other resistant metamorphic rock types. Restricted to shoreline in Marquette CountyGranite Lakeshore Cliff
                  • 20B. Composed of volcanic bedrock including basalt and volcanic conglomerate. Virtually restricted to shoreline along Keweenaw Peninsula and Isle RoyaleVolcanic Lakeshore Cliff
          • 16B. Located inland from the Great Lakes shorelineGo to 21A or 21B [Inland Cliff Group]
            • 21A. Occurring primarily on the Niagaran Escarpment in the eastern and south-central Upper Peninsula and rarely in the western Upper Peninsula and northeastern Lower Michigan. Substrate limestone and/or dolomite bedrock including Kona dolomite in Marquette CountyLimestone Cliff
            • 21B. Occurring primarily in the western and north-central Upper Peninsula. Substrate sandstone, granitic, or volcanic bedrockGo to 22A or 22B
              • 22A. Occurring primarily in the Upper Peninsula and very rarely in the southern Lower Peninsula. Substrate sandstone bedrockSandstone Cliff
              • 22B. Restricted to the Upper Peninsula. Substrate granitic or volcanic bedrockGo to 23A or 23B
                • 23A. Cliff primarily composed of granitic bedrock, which may include granite, quartzite, schist, gabbro, gneiss, and a diversity of other resistant igneous and metamorphic rock typesGranite Cliff
                • 23B. Cliff primarily composed of volcanic bedrock including basalt and volcanic conglomerateVolcanic Cliff

Subterranean/Sink Class Key

  • 1. Subterranean or sink feature located in areas of karst topography primarily along the Niagaran Cuesta in the eastern Upper Peninsula and northeastern Lower PeninsulaGo to 2A or 2B [Karst Group]
    • 2A. Occurring as cavities beneath the earth’s surface, often with an opening to the surface, characterized by little or no light, no primary producers, and biotic communities of one or two trophic levels that import energy from outside the systemCave
    • 2B. Occurring as large depressions caused by the dissolution and collapse of subsurface limestone, dolomite, or gypsum. Bottoms of depressions sometimes filled with water. Exposed limestone vertical walls and large boulders sometimes present. Vegetative composition and structure generally reflect that of surrounding landscapeSinkhole

Citation

Cohen, J.G., M.A. Kost, B.S. Slaughter, D.A. Albert, J.M. Lincoln, A.P. Kortenhoven, C.M. Wilton, H.D. Enander, and K.M. Korroch. 2020. Michigan Natural Community Classification [web application]. Michigan Natural Features Inventory, Michigan State University Extension, Lansing, Michigan. Available https://mnfi.anr.msu.edu/communities/classification. (Accessed: November 27, 2020).