Natural Communities of NH -- Photo Guide

Seasonally flooded red maple swamp  (S4)

Seasonally flooded red maple swamp
is a common type of red maple swamp associated with stream drainages that are seasonally flooded, particularly along low-gradient sections of first, second, or third order streams (less commonly fourth). They contain an abundance of clonal graminoids and other meadow marsh plants such as tussock sedge, bluejoint, and meadowsweet.

Soils are typically alluvial or are shallow muck or peat over alluvial mineral soils. These swamps differ from floodplain forests by having a seasonally rather than temporarily flooded water regime, and being lower energy environments that allow the development of organic or organic-rich soils as opposed to mineral soils with no organic horizon. They are commonly successional from meadow marshes (wet meadows) or emergent marshes and have either a woodland or forest canopy structure.

Characteristic Vegetation: Red maple (Acer rubrum) is the primary or sole tree species. American elm (Ulmus americana) may be an occasional associate. The shrub layer is poorly to moderately dense depending on the successional sequence. Shrubs that can occur include winterberry (Ilex verticillata), speckled alder (Alnus incana ssp. rugosa), red osier dogwood (Cornus sericea), meadowsweet (Spiraea alba), male berry (Lyonia ligustrina), highbush blueberry (Vaccinium corymbosum), and others.

Clonal graminoids such as tussock sedge (Carex stricta) and bluejoint (Calamagrostis canadensis) are the most frequent herbaceous dominants. Numerous other wetland herbs of marshes and swamps may be present including marsh fern (Thelypteris palustris var. pubescens), marsh St. John's-wort (Triadenum virginicum), swamp candles (Lysimachia terrestris), water horehound (Lycopus spp.), sensitive fern (Onoclea sensibilis), flat-topped white aster (Doellingeria umbellata), New York aster (Symphyotrichum novi-belgii), and lesser bur-reed (Sparganium americanum). Peat moss (Sphagnum spp.) cover is generally low.

A good example of this community occurs at Northwood Meadows State Park (Northwood).

Seasonally flooded red maple swamps sometimes occur as part of temperate peat swamp systems, temperate minerotrophic swamp systems, or emergent marsh - shrub swamp systems.

Seasonally flooded red maple swamp (photo by Dan Sperduto for the NH Natural Heritage Bureau)
Seasonally flooded red maple swamp (photo by Dan Sperduto)

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