Natural Community Systems -- Photo Guide

Montane rocky ridge system

montane rocky ridge system on Orange Mtn. near Mt. Cardigan (photo by Ben Kimball for the NH Natural Heritage Bureau)
montane rocky ridge system on Orange Mtn. near Mt. Cardigan (photo by Ben Kimball)

montane rocky ridge system on Cape Horn (photo by Ben Kimball for the NH Natural Heritage Bureau)
montane rocky ridge system on Cape Horn (photo by Ben Kimball)

 

Description: Montane rocky ridge systems occur on outcrops and shallow-to-bedrock ridges and summits at mid-elevations in New Hampshire.  They are dominated by some combination of Picea rubens (red spruce), Pinus resinosa (red pine), and Quercus rubra (red oak).  Outcrops include cliff slabs, which are steep bedrock exposures of less than 65 degree slope.  This system includes nearly all the rocky ridges in the White Mountain region and other rocky exposures between 1,300–3,000 ft. elevation elsewhere in the state.  These rocky ridges, summits, and slabs have a woodland to sparse woodland canopy structure (ranging from completely open patches to thin forest cover >65%), much open bedrock exposure, and one or more of the three primary diagnostic communities that overlap in their elevation ranges.  Red oak - pine rocky ridges occur between 1,000–1,800 ft.; red pine rocky ridges between 900–2,700 ft. (most are between 1,400–2,400); and red spruce - heath - cinquefoil rocky ridges from 1,700–3,000 ft.  Jack pine rocky ridge woodland communities occur at a few sites in the White Mountains up to about 4,000 ft. elevation.  Many ridge, slab, and outcrop areas are characterized by two or sometimes all three of these diagnostic communities depending on the elevation range or other ecological influences present at the site.  Although many specific locations on the ground correspond definitively to one of these communities, ambiguous transition areas are also common, where the three primary species (red oak, red pine, and red spruce) mix in various combinations.  Small cliffs are found in some examples of this system.  In contrast with montane rocky ridge and slab systems, Appalachian oak rocky ridge systems occur at lower elevations away from the White Mtns (mostly <1,000 ft., but occasionally to 1,200 ft.) and have numerous southern species such as Appalachian oaks (white, black, scarlet, and scrub) and hickory and little or no red pine or red spruce. 


Diagnostic natural communities:

      • Red spruce - heath - cinquefoil rocky ridge (S3S4)

      • Red pine rocky ridge (S2)

      • Red oak - pine rocky ridge (S3S4)

      • Jack pine rocky ridge woodland (S1)

      • Montane heath woodland (S2)

Peripheral or occasional natural communities:

      • Montane - subalpine acidic cliff (S5)

       Montane level fen/bog (S2)


Landscape settings: outcrops and shallow-to-bedrock areas on ridges, summits, and steep side slopes

Soils: shallow, very acidic, organic and turfy mineral materials over bedrock

Spatial pattern: irregular and elliptically linear (along ridges) with frequent outcrops (<5–100+ acres); irregular zonation

Physiognomy: woodland and sparse woodlands with trees, short shrubs, and some herbs; sparsely vegetated outcrop openings are embedded at a finer scale

Distribution: mid-elevations (1,300–3,000 ft.) in western and northern NH, most abundant in the White Mountains


Characteristic species:
Trees
   Picea rubens (red spruce)
   Pinus resinosa (red pine)
   Pinus banksiana (jack pine)
   Quercus rubra (red oak)
   Abies balsamea (balsam fir)
   Betula cordifolia (heartleaf birch)
   Sorbus americana (American mountain ash)
   Sorbus decora (showy mountain ash)

Shrubs
   Vaccinium myrtilloides (velvet-leaf blueberry)
   Rhododendron canadense (rhodora)
   Amelanchier bartramiana (Bartram's serviceberry)
   Potentilla tridentata (three-toothed cinquefoil)

Herbs
   Solidago randii (Rand's goldenrod)
   Paronychia argyrocoma var. albimontana (silverling)
   Oryzopsis canadensis (Canadian rice-grass)
   Polygonum douglasii (Douglas' knotweed)


Species common to both montane and Appalachian rocky ridges:
   Vaccinium angustifolium (lowbush blueberry)
   Deschampsia flexuosa (common hair-grass)
   Betula papyrifera (paper birch)
   Maianthemum canadense (Canada mayflower)
   Kalmia angustifolia (sheep laurel)
   Pteridium aquilinum var. latiusculum (bracken fern)
   Gaultheria procumbens (wintergreen)


Associated natural community systems: Downslope, this system sometimes transitions to montane cliff, montane acidic talus, or rich north-temperate talus/rocky slope systems.  Upslope (when it exists), this system transitions to subalpine heath - krummholz/rocky bald, northern hardwood - conifer, or high-elevation spruce - fir - (northern hardwood) forest systems.


montane rocky ridge system at Mt. Cardigan (photo by Ben Kimball)
montane rocky ridge system at Mt. Cardigan (photo by Ben Kimball)

montane rocky ridge system on Mt. Chocorua (photo by Ben Kimball)
montane rocky ridge system on Mt. Chocorua (photo by Ben Kimball)


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