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Wet Clayplain Forest

Ecology and Physical Settingillustration of wet clayplain forest

Wet Clayplain Forests most commonly occur as small wetland patches within surrounding, larger areas of Mesic Clayplain Forest. On these level clay-soil plains, a few inches to a foot of elevation makes a big difference. In low areas, water accumulates and wetland conditions develop, whereas in slightly higher areas, there is adequate drainage to support upland communities. These forests also occur on low-lying, broad clay flats where drainage is slow and wet conditions persist. Often these larger patches are surrounded by upland clay soils that at one time supported Mesic Clayplain Forests. The forests on these drier soils were cleared for agriculture, while the Wet Clayplain Forests were too wet to bother with. 

boardwalk going through a wet clayplain forestWet Clayplain Forests typically occur on poorly-drained clays, including Covington, Panton, Kingsbury, and Livingston soils. These soils hold water for a long time in the spring but may become quite dry during droughty summer months. When these wetland forests occur as mosaics with Mesic Clayplain Forests, they are difficult to map separately due to the fine scale at which these communities intermingle.

Wet Clayplain Forest is one of the natural communities of the Champlain Valley clayplain forest ecosystem, which is described under the Mesic Clayplain Forest natural community. 

Vegetation

Wet Clayplain Forests are dominated by wetland species, but unlike most other wetland forests and swamps, They also support some upland species, albeit in low abundance. This likely reflects the seasonally dry soils of many Wet Clayplain Forests, in contrast to swamps with permanently saturated soils. Buttressed trunks and raised, shallow roots characterize trees in Wet Clayplain Forests.

Wet Clayplain Forests have the most diverse assemblages of tree species of any swamp or wet forest in Vermont. Green ash, swamp white oak, black ash, bur oak, American elm, and red maple dominate their closed canopies. Common wetland and upland canopy associates include white oak, white ash, hemlock, white pine, yellow birch, shagbark hickory, northern white cedar, and silver maple. Musclewood is a common understory tree.

The often dense tall shrub layer includes winterberry holly, arrowwood, and highbush blueberry. Herbs are mostly wetland species, and cover and composition can vary from site to site. Common species include sensitive fern, interrupted fern, cinnamon fern, wood nettle, royal fern, dwarf raspberry, northern bugleweed, hog peanut, foamflower, brome-like sedge, hop sedge, and Tuckerman’s sedge. In some of the wettest forests, lake sedge may be dominant. 

Wildlife Habitat

The remnants of the clayplain forest ecosystem in the fragmented Champlain Valley are critically important for many species of wildlife. The wildlife habitat provided by any patch of Wet Clayplain Forest is shaped by the forest itself and by the surrounding Mesic Clayplain Forest and other communities. Larger and deeper depressions in Wet Clayplain Forests may hold water long enough to provide breeding habitat for spotted salamanders, wood frogs, and blue-spotted salamanders. Gray treefrogs, which breed in open water, may be abundant in these wet woods when marshes with permanent water are nearby. Breeding birds include veery, winter wren, and the rare blue-gray gnatcatcher. Shagbark hickory, which can be locally abundant in Wet Clayplain Forests, provides habitat for two notable species. Caterpillars of the uncommon hickory hairstreak butterfly rely on hickory as their primary food source. The globally rare Indiana bat roosts under the shedding, platy bark.

Related Communities

  • Mesic Clayplain Forest occurs on moderately well-drained clay soils (typically Vergennes soils) and is dominated by upland tree species, primarily red oak, white oak, shagbark hickory, sugar maple, and white ash. These two communities commonly form a patchy mosaic.

     
  • Wet Sand-Over-Clay Forest is also a wetland community of the clayplain forest ecosystem. It occurs on poorly drained soils with wet sand overlying clay or silt. The sandy overburden creates a more acidic, nutrient-poor environment. Red maple, green ash, and swamp white oak dominate. 

Conservation Status and Management Considerations

This rare, small patch wetland natural community now occupies a fraction of its distribution before European settlement. It is a characteristic community of the Champlain Valley, and it hosts an unusual assemblage of plants and animals. There are several good examples on conserved lands, but it is important to protect other examples, and to restore and maintain the natural ecological processes and species composition. Connections between these patches of forest are critical for wildlife movement and the long-term viability of the clayplain forest ecosystem.

Distribution/Abundancemap of Vermont with locations of natural community

In Vermont, this rare natural community is almost entirely restricted to the Champlain Valley. Isolated examples have been documented in the Southern Vermont Piedmont and Vermont Valley. Closely related communities occur in the lower Great Lakes region.

Characteristic Plants

Trees

Abundant Species

Green ash – Fraxinus pennsylvanica 

Swamp white oak – Quercus bicolor

Black ash – Fraxinus nigra 

Bur oak – Quercus macrocarpa

American elm – Ulmus americana

Red maple – Acer rubrum 

Occasional to Locally Abundant Species

White oak – Quercus alba

White ash – Fraxinus americana

Eastern hemlock – Tsuga canadensis

Red oak – Quercus rubra

White pine – Pinus strobus 

Yellow birch – Betula alleghaniensis

Shagbark hickory – Carya ovata

Musclewood – Carpinus caroliniana

Northern white cedar – Thuja occidentalis 

Basswood – Tilia americana 

Silver maple – Acer saccharinum

Shrubs

Winterberry holly – Ilex verticillata

Arrowwood – Viburnum dentatum

Highbush blueberry – Vaccinium corymbosum 

Silky dogwood – Cornus amomum 

Herbs

Sensitive fern – Onoclea sensibilis

Hog peanut – Ampicarpaea bracteata

Foamflower – Tiarella cordifolia

Interrupted fern – Osmunda claytoniana

Wood nettle – Laportea canadensis

Royal fern – Osmunda regalis

Cinnamon fern – Osmundastrum cinnamomeum

Dwarf raspberry – Rubus pubescens

Northern bugleweed – Lycopus uniflorus

Jack-in-the-pulpit – Arisaema triphyllum

Common jewelweed – Impatiens capensis

Lake sedge – Carex lacustris

Brome-like sedge – Carex bromoides

Hop sedge – Carex lupulina

Tuckerman’s sedge – Carex tuckermanii

Lady fern – Athyrium filix-femina

Bladder sedge – Carex intumescens

False nettle – Boehmeria cylindrica

Crested wood fern – Dryopteris cristata

Marsh fern – Thelypteris palustris

Whitegrass – Leersia virginica

Stout woodreed – Cinna arundinacea

Rough avens – Geum laciniatum 

Slender mannagrass – Glyceria melicaria 

Skunk cabbage – Symplocarpus foetidus

Bailey’s sedge – Carex baileyi

Bryophytes

Tree moss – Climacium dendroides 

Common fern moss – Thuidium delicatulum 

Moss – Calliergon cordifolium 

Three-lobed bazzania – Bazzania trilobata

Rare and Uncommon Plants

Green dragon – Arisaema dracontium 

Buxbaum’s sedge – Carex buxbaumii

False hop sedge – Carex lupuliformis

American hazelnut – Corylus americana 

Gray’s sedge – Carex grayi

Virginia bugleweed – Lycopus virginicus

Cattail sedge – Carex typhina 

Associated Animals

Spotted salamander – Ambystoma maculatum

Wood frog – Lithobates sylvaticus 

Gray treefrog – Hyla versicolor 

Winter wren – Troglodytes hiemalis 

Veery – Catharus fuscescens 

Great crested flycatcher – Myiarchus crinitus 

Rare and Uncommon Animals

Blue-spotted salamander – Ambystoma laterale

Indiana bat – Myotis sodalis

Red-shouldered hawk – Buteo lineatus 

Blue-gray gnatcatcher – Polioptila caerulea 

Hickory hairstreak – Satyrium caryaevorus 

Places to Visit

Round Pond State Park, South Hero, Vermont Department of Forests, Parks, and Recreation



LaPlatte River Marsh Natural Area, Shelburne, The Nature Conservancy



Dead Creek Wildlife Management Area, Addison, Vermont Fish and Wildlife Department



Shellhouse Mountain, Ferrisburgh Municipal Forest