Natural Community Systems -- Photo Guide

Rich Appalachian oak rocky woods system

Rich Appalachian oak rocky woods system at Pawtuckaway State Park (photo by Ben Kimball for the NH Natural Heritage Bureau)
Rich Appalachian oak rocky woods system at Pawtuckaway State Park (photo by Ben Kimball)

 

Description:  This system is the southern equivalent of rich north-temperate talus/rocky woods system.  It occurs on hillsides, mostly below 500 ft. in the southern part of the state (generally within 30 miles of the coast or Massachusetts border), with rocky to shallow till substrates.  It is indicated by a host of southern plants that do not occur further north or at higher elevations.  There are two primary natural communities, rich Appalachian oak rocky woods and red oak - ironwood - Pennsylvania sedge woodlandTemperate lichen talus barrens are small and rare in this system, as are patches of rich mesic forest.  This system typically transitions to more nutrient poor, rocky conditions on the ridge tops classified as Appalachian oak rocky ridge system, but occasionally they occupy the ridgetop settings as well where the red oak - ironwood - Pennsylvania sedge woodland community dominates.  The hillsides on which this system occurs include talus, other unconsolidated, loose rocky slopes, and relatively shallow till soils with occasional outcrops.

Many of the diagnostic plants listed for rich north-temperate talus/rocky woods system occur in this system.  Indicators of the primary community (rich Appalachian oak rocky woods) in this more southern system include hickories, flowering dogwood, oaks other than red oak, and a wide variety of herbs and shrubs that reach their northeastern limit in southern NH.  Areas dominated by Carex pensylvanica (Pennsylvania sedge) lawns indicate the red oak - ironwood - Pennsylvania sedge woodland community, which tends to occur somewhat higher on hillside slopes and even onto adjacent ridgelines compared to the rich Appalachian oak rocky woods community.  These two communities are frequently found together in this system.


Diagnostic natural communities:

      • Rich Appalachian oak rocky woods (S2)

      • Red oak - ironwood - Pennsylvania sedge woodland (S2)

      • Appalachian wooded talus (S1S2)


Peripheral or occasional natural communities:

      • Rich mesic forest (S3)

      • Semi-rich oak - sugar maple forest (S2S3)

      • Appalachian oak - pine rocky ridge (S3)

      • Chestnut oak forest/woodland (S1S2)

      • Temperate lichen talus barren (S2S3)


Landscape settings: talus or other rocky slopes in neutral to concave hillside slope positions, and occasionally upper-slope positions, particularly in regions of calcium-rich bedrock

Soils: overall dry-mesic with embedded dry and mesic micro-sites, well to somewhat excessively well drained; moderate to shallow depth fine sandy loams with considerable gravel and stone content with frequent outcrops, talus boulders, and/or unconsolidated stones; sometimes with a well-mixed “mull” A horizon

Spatial pattern: small to large patches (1–200+ acres); variably shaped, although often elliptical or broad-linear when controlled by topographic position (i.e., cliff-bases and hillside slopes)

Physiognomy: woodland to forest, rarely with patches of un- or sparsely-vegetated lichen talus barrens

Distribution: low elevations in southern New Hampshire, mostly below 500 ft., ranging to ca. 1,000 ft.


Characteristic species:

Rich Appalachian oak rocky woods (plants listed for rich north-temperate talus/rocky woods system are also found in this system):

Southern species generally not found in north-temperate type:
Trees and shrubs
   Quercus alba (white oak)
   Carya ovata (shagbark hickory)
   Carya ovalis (sweet pignut hickory)
   Carya cordiformis (bitternut hickory)
   Carya glabra (pignut hickory)
   Quercus prinus (chestnut oak)
   Quercus velutina (black oak) -- ridgetops
   Quercus coccinea (scarlet oak) -- ridgetops
   Cornus florida (flowering dogwood)
   Viburnum rafinesquianum (downy arrowwood)

Herbs
   Asplenium platyneuron (ebony spleenwort)
   Ranunculus fascicularis (early buttercup)
   Aster patens (skydrop aster)
   Arabis canadensis (sickle-pod)
   Arabis laevigata (smooth rock cress)
   Arabis missouriensis (Missouri rock cress)
   Aureolaria virginica (downy false foxglove)
   Carex retroflexa (reflexed sedge)
   Lespedeza virginica (slender bush-clover)
   Pycnanthemum incanum (hoary mountain mint)
   Paronychia canadensis (smooth-forked chickweed)
   Anemonella thalictroides (rue anemone)
   Asclepias quadrifolia (four-leaved milkweed)   
   Woodsia obtusa (blunt-lobed woodsia)
   Muhlenbergia sobolifera (sprout muhlenbergia)
   Viola pedata (bird’s-foot violet)


Associated natural community systems This system typically transitions to oak – pine forest systems or sometimes hemlock – hardwood – pine forest systems.  More xeric conditions along adjacent ridgetops often mark the transition to Appalachian oak rocky ridge systems that lack the rich-site indicators of rich Appalachian oak rocky woods systems.



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