Natural Community Systems -- Photo Guide

Coastal conifer peat swamp system

coastal conifer peat swamp system at Locke Pond in Rye (photo by Ben Kimball for the NH Natural Heritage Bureau)
coastal conifer peat swamp system at Locke Pond in Rye (photo by Ben Kimball)


Description:  This system corresponds to acidic, oligotrophic peatlands in central and southern New Hampshire dominated by Chamaecyparis thyoides (Atlantic white cedar), and occasionally Pinus rigida (pitch pine).  The system is characterized by one or more of the five Atlantic white cedar natural communities.  Atlantic white cedar dominates some or all of a peatland basin, mixing in some areas with red maple - Sphagnum basin swamps and tall shrub fen communities.  It is found both in association with, and in isolation of, open peatland systems.  This system occurs on moderately to very deep peat with pHs less than 5, although pH and trophic levels can be higher around the system margins where there is a shift in natural community type.  Some inland examples of this system are very acidic (pHs as low as 3.4); seasonally flooded portions of these systems that transition to emergent marshes have higher pHs (4.4 to 6.5).  Coastal plain and southern species are more common in this wetland system than in more inland, northern, or higher elevation temperate peat swamps.  These include Clethra alnifolia (sweet pepperbush), Rhododendron maximum (giant rhododendron), and Sphagnum flavicomans (peat moss).  Patches of tall shrub peatland thickets (fens with <25% tree cover) are common as part of the swamp mosaic.  Where these tall shrub fens become extensive, they may be best considered part of an adjacent open peatland system.

Diagnostic natural communities:

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

   • Inland Atlantic white cedar swamp (S1)

   • Atlantic white cedar - leatherleaf swamp (S1)

   • Atlantic white cedar - giant rhododendron swamp (S1) 

   • Seasonally flooded Atlantic white cedar swamp (S2)

   • Pitch pine - heath swamp (S1S2)

   • Sweet pepperbush wooded fen (S2)

   • Highbush blueberry - mountain holly wooded fen (S3S4)

   • Red maple - Sphagnum basin swamp (S4)

Peripheral or occasional natural communities:

   • Black gum - red maple basin swamp (S1S2)

   • Highbush blueberry - winterberry shrub thicket (S4)

Landscape settings: stagnant, closed or open headwater basins with limited drainage; often in depressions in glacial outwash or ice-contact deposits or broad lake basins away from the influence of lake water

Soils: deep, moderately well decomposed peat; oligotrophic to weakly minerotrophic; pHs generally less than 5, occasionally higher; topogenous

Spatial pattern: small to large patch (<530+ acres); circular to irregular shape; uniform or forming exterior zone around open peatlands, sometimes in mosaics with more open peatlands

Physiognomy: forest to woodland with tall shrub patches

Distribution: found in coastal New Hampshire with disjuncts in the highlands of southwest New Hampshire, in the Merrimack Valley and the Lakes Region

Characteristic species:
      Chamaecyparis thyoides (Atlantic white cedar)
      Acer rubrum (red maple)
      Betula alleghaniensis (yellow birch)
      Tsuga canadensis (hemlock)
      Picea rubens (red spruce)

      Ilex verticillata (winterberry)
      Vaccinium corymbosum (highbush blueberry)
      Nemopanthus mucronatus (mountain holly)
      Clethra alnifolia (sweet pepperbush)
      Rhododendron maximum (giant rhododendron)
      Kalmia latifolia (mountain laurel)
      Kalmia angustifolia (sheep laurel)

      Osmunda cinnamomea (cinnamon fern)
      Coptis trifolia (goldthread)
      Mitchella repens (partridgeberry)
      Osmunda regalis var. spectabilis (royal fern)
      Carex trisperma var. trisperma (three-seeded sedge)
      Thelypteris simulata (Massachusetts fern)

Associated natural community systemsThis system is often found in association with poor level fen/bog systems, kettle hole bog systems, and in stagnant headwater basins in isolation of other peatlands or open wetlands.  It is most similar to the temperate peat swamp system, which is largely hardwood dominated, more common, and ranges further northward, inland, and to higher elevations.

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