Natural Communities of NH -- Photo Guide

Atlantic white cedar - yellow birch - pepperbush swamp  (S2)


Atlantic white cedar - yellow birch - pepperbush swamps generally occur in wet basins at low elevations (20 - 350 ft.) within 30 miles of the coast. The community is characterized by a mix of Atlantic white cedar, yellow birch, red maple, sweet pepperbush, and other coastal or southern species. Hummock and hollow topography is pronounced and hollows are often wet throughout the growing season. Soil pH is generally of medium acidity (mediacid) and ranges from 4.0-5.1.

Characteristic Vegetation: Atlantic white cedar (Chamaecyparis thyoides) is the dominant canopy tree. Sweet pepperbush (Clethra alnifolia), yellow birch (Betula alleghaniensis), and red maple (Acer rubrum) are frequent and sometimes abundant. Hemlock (Tsuga canadensis) is occasionally abundant, although absent at some sites. Winterberry (Ilex verticillata), highbush blueberry (Vaccinium corymbosum), mountain holly (Nemopanthus mucronatus), peat mosses (Sphagnum spp.), and white pine (Pinus strobus) are abundant or frequent.

Herbs are frequent on hummocks, especially wild sarsaparilla (Aralia nudicaulis), starflower (Trientalis borealis), Canada mayflower (Maianthemum canadense), and mosses. Other species include cinnamon fern (Osmunda cinnamomea), goldthread (Coptis trifolia), partridgeberry (Mitchella repens), royal fern (Osmunda regalis var. spectabilis), three-seeded sedge (Carex trisperma), sheep laurel (Kalmia angustifolia), and Massachusetts fern (Thelypteris simulata). The rare coastal plain species separated sedge (Carex seorsa) and Walter's sedge (Carex striata var. brevis) occur in some examples.

Three-seeded sedge and sheep laurel are occasional in this type of Atlantic white cedar swamp but are generally absent from the seasonally flooded type. Massachusetts fern appears to be restricted to this and the Atlantic white cedar - giant rhododendron swamp type. Swamp azalea (Rhododendron viscosum) is generally characteristic of coastal cedar swamps in southern New England, but is absent in this type. Species indicative of northern or marshy conditions that characterize the other types of Atlantic white cedar swamp are also infrequent or absent.


Good examples of this community occur at Cedar Swamp Pond (Kingston), Powwow Pond and Country Pond vicinities (Kingston), and Stratham Hill Park (Stratham).

Atlantic white cedar - yellow birch - pepperbush swamps may occur as part of a coastal conifer peat swamp system.


AWC - YB - sweet pepperbush swamp at Stratham Hill Park (photo by Ben Kimball for the NH Natural Heritage Bureau)
Atlantic white cedar - yellow birch - pepperbush swamp
at Stratham Hill Park (photo by Ben Kimball)

AWC - yellow birch - pepperbush swamp (heavy to pepperbush due to flooding of the cedar) in Hampstead (photo by Ben Kimball for the NH Natural Heritage Bureau)
Atlantic white cedar - yellow birch - pepperbush swamp
(heavy to pepperbush due to flooding of the cedar) in Hampstead (photo by Ben Kimball)

AWC - yellow birch - pepperbush swamp at Cedar Swamp Pond in Kingston (photo by Ben Kimball for the NH Natural Heritage Bureau)
Atlantic white cedar - yellow birch - pepperbush swamp
at Cedar Swamp Pond in Kingston (photo by Ben Kimball)

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