Natural Communities of NH -- Photo Guide

Hemlock - cinnamon fern forest  (S4)

Hemlock - cinnamon fern forest
 has a seasonally-high water table, and as such is a transitional community type exhibiting some of the characteristics of a forest and some of the characteristics of a swamp. It occurs in imperfectly to somewhat poorly drained areas along stream drainages, high floodplains, inactive river terraces, and other upland-wetland ecotones, and is characterized by hemlock, red maple, and a mixture of other wetland and upland plant species. Examples may occur along a narrow transition zone between uplands and wetlands or may be broader in extent and cover several acres. Although some sub-surface seepage may influence certain examples, this community appears distinct from seepage forest and forest seep communities, which tend to have relatively constant surface or near-surface seepage influence and more seepage or minerotrophic plant indicators.

Soils are nutrient-poor. They vary from loamy sands to sandy loam till and river/kame terrace soils with a shallow water table (within 0.3 m (1 ft.) of soil surface for portion of growing season). Mottles are evident within 30 cm (12 in.) of the soil surface in some examples, while others have deep A horizons (tending to obscure mottles) over moist to wet sediments. Soils include series Au Gres, among other types.

Characteristic vegetation:
Hemlock (Tsuga canadensis) and red maple (Acer rubrum) dominate in the overstory. Canopy associates may include white pine (Pinus strobus), yellow birch (Betula alleghaniensis), and, less frequently, swamp white oak (Quercus bicolor), red oak (Quercus rubra), black birch (Betula lenta), American elm (Ulmus americana), and black cherry (Prunus serotina). White ash (Fraxinus americana) may also be prominent in the tree canopy at upland-wetland ecotones. Other woody species can include sheep laurel (Kalmia angustifolia), highbush blueberry (Vaccinium corymbosum), witherod (Viburnum nudum), beech (Fagus grandifolia), swamp rose (Rosa palustris), western black raspberry (Rubus occidentalis), common elderberry (Sambucus canadensis), striped maple (Acer pensylvanicum), hobblebush (Viburnum lantanoides), red spruce (Picea rubens), and balsam fir (Abies balsamea).

Although the overstory association can approximate certain upland forests, more mesic to wet conditions are indicated by the presence of cinnamon fern (Osmunda cinnamomea), interrupted fern (Osmunda claytoniana), Jack-in-the-pulpit (Arisaema triphyllum), marsh fern (Thelypteris palustris), Canadian honeysuckle (Lonicera canadensis), northern spicebush (Lindera benzoin), and various mosses. Other herbs may include New York fern (Thelypteris noveboracensis), wild sarsaparilla (Aralia nudicaulis), whorled aster (Aster acuminatus), intermediate wood fern (Dryopteris intermedia), partridgeberry (Mitchella repens), northern wood sorrel (Oxalis acetosella), and bluebead lily (Clintonia borealis).

Good examples
of this community occur in the Allard Brook vicinity along the Swift River (Albany), at Bear Brook State Park (Allenstown), at Northwood Meadows State Park (Northwood), and near the Exeter River (Exeter).

Hemlock - cinnamon fern forests sometimes occur as part of temperate peat swamp systems and temperate minerotrophic swamp systems.

Hemlock - cinnamon fern forest at Northwood Meadows State Park (photo by Ben Kimball for the NH Natural Heritage Bureau)
Hemlock - cinnamon fern forest at Northwood Meadows State Park. Cinnamon fern, moss, and
a red maple trunk are in the foreground; hemlock is in the background. (photo by Ben Kimball)

Hemlock - cinnamon fern forest (photo by Dan Sperduto for the NH Natural Heritage Bureau)
Hemlock - cinnamon fern forest (photo by Dan Sperduto)

back to Natural Communities of NH Photo Guide