Natural Communities of NH -- Photo Guide

Red pine rocky ridge  (S2)



Red pine rocky ridge
communities red pine (Pinus resinosa) dominated forests and woodlands. They are most prominent on dry, montane rocky ridges, outcrops, and summits where acidic, nutrient-poor conditions prevail. Red pine stands are often even-aged and have park-like understories with a low heath shrub layer. Even-aged cohorts typically develop following an intense fire. This community is most common on south-facing slopes between 750–2,700 ft. elevation in northern, mountainous parts of the state. Typical examples consist of mosaics of open or partially vegetated rock outcrops interspersed with a scattered or patchy tree canopy. Rock exposures generally cover 25–50% of the ground surface. In some areas, particularly those with deeper soils or ones that have only a distant fire-history, red pine may form an essentially closed canopy. Red pine trees may exceed 60–70 ft (18–21 m) in height, but are, on average, shorter in woodland settings and at higher elevations. A closed forest canopy may form in the absence of fire for long periods or where soils are better developed. Shade-intolerant species tend to be less abundant or absent in forested examples.

Fire plays an important role in the formation and maintenance of this community, and controlled burns or wildfire may be required for substantial regeneration of red pine, whether or not harvesting is performed. Red pine can exceed 200 years of age, and the bark of this tree thickens with age. By 70 years, the thickness of the bark of mature trees is sufficient to protect them from fire. Younger trees have thinner bark and may not survive an intense fire. Thus, red pine is favored by fire return intervals of 70 or more years. In the absence of fire, red spruce (Picea rubens) may replace red pine as the dominant tree in higher elevation examples, over time shifting the community type to red spruce - heath - cinquefoil  rocky ridge.

Soils are thin, dry, and acidic with turfy (fibric) organic surface horizons and gravelly and/or coarse sand mineral layers over bedrock.

This is a distinct, narrowly defined community that intergrades with other northern rocky ridge communities. It is considered distinct from the red oak and jack pine types due to differences in dominant tree species and probable differences in ecological histories or circumstances. This community type includes outcrops in other landscape positions (i.e. not rocky ridges), such as along rocky lake shores that exhibit similar vegetation assemblages.

Characteristic vegetation:
Besides the dominant red pine, other tree species that may be present include red oak (Quercus rubra), white pine (Pinus strobus), red spruce (Picea rubens), paper birch (Betula papyrifera), heartleaf birch (Betula cordifolia), balsam fir (Abies balsamea), and red maple (Acer rubrum).

Characteristic tall shrub species include Bartram's serviceberry (Amelanchier bartramiana), witherod (Viburnum nudum var. cassinoides), American mountain ash (Sorbus americana), red chokeberry (Photinia pyrifolia), mountain holly (Nemopanthus mucronatus), and striped maple (Acer pensylvanicum). Some common low shrubs are lowbush blueberry (Vaccinium angustifolium), velvet-leaf blueberry (Vaccinium myrtilloides), black huckleberry (Gaylussacia baccata), sheep laurel (Kalmia angustifolia), and bush honeysuckle (Diervilla lonicera).

The herb layer is often sparse, but can occasionally be dense, and includes such species as bracken (Pteridium aquilinum var. latiusculum), common hairgrass (Deschampsia flexuosa), poverty oatgrass (Danthonia spicata), trailing arbutus (Epigaea repens), rock polypody (Polypodium virginianum), rough-leaved rice grass (Oryzopsis asperifolia), pale corydalis (Corydalis sempervirens), distant sedge (Carex lucorum), and pink lady's slipper (Cypripedium acaule). Mosses and lichens are typically abundant on rock outcrop areas.

Variants:
Two variants are described:

1. Low-elevation variant
   900 - 2,000 feet.; more frequent occurence of southern species such as huckleberries (Gaylussacia spp.), red oak (Quercus rubra), pale corydalis (Corydalis sempervirens), trailing arbutus (Epigaea repens), wintergreen (Gaultheria procumbens), distant sedge (Carex lucorum), and slender mountain rice (Piptatherum pungens); floristically similar to red oak - pine rocky ridge community.

2. High-elevation variant
   1,900 - 2,700 feet.; contains more northern species such as red spruce (Picea rubens), Rand's goldenrod (Solidago simplex), three-toothed cinquefoil (Sibbaldiopsis tridentata), American mountain ash (Sorbus americana), and Bartram's serviceberry (Amelanchier bartramiana).; floristically similar to red spruce - heath - cinquefoil  rocky ridge community.


Good examples of this community occur on Owls Head/Blueberry Mtn. (Benton), White's Pinnacle (East Haverhill), Black Mountain (Benton), Mt. Stanton (Bartlett), Peaked Mountain (Conway), and Cape Horn (Northumberland).

Red pine rocky ridges sometimes occur as inclusions within larger montane rocky ridge systems.


Red pine rocky ridge at Cape Horn State Forest (photo by Ben Kimball for the NH Natural Heritage Bureau)
Red pine rocky ridge at Cape Horn State Forest near Groveton (photo by Ben Kimball)

Red pine rocky ridge in winter at Black Mountain State Forest (photo by Ben Kimball for the NH Natural Heritage Bureau)
Red pine rocky ridge in winter at Black Mountain State Forest in Haverhill (photo by Ben Kimball)

Red pine rocky ridge on South Moat Mtn. (photo by Pete Bowman)
Red pine rocky ridge on South Moat Mtn. in Albany (photo by Pete Bowman)

red pine rocky ridge community on Middle Mountain (photo by Ben Kimball for the NH Natural Heritage Bureau)
red pine rocky ridge community on Middle Mountain in Conway (photo by Ben Kimball)


red pine rocky ridge canopy at Black Mtn. State Forest (photo by Ben Kimball for the NH Natural Heritage Bureau)
red pine rocky ridge canopy at Black Mtn. State Forest (photo by Ben Kimball)

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