Pitch pine rocky ridge
Pitch pine rocky ridge (S1)
This Pitch pine (Pinus rigida) dominated community is found in southern and east-central New Hampshire on rocky summits and ridges with a history of fire. Pitch pine forms a stunted to moderate-height (5–30 ft. tall), sparse woodland (5–25%) to woodland (25–60%) tree canopy cover, sometimes in combination with other conifers and oaks. On the most barren and xeric microsites within the community, scattered bonsai-like pitch pine trees grow to 5–15 feet tall and can exceed 70 years of age.
This community is similar to other pine and oak dominated rocky ridge communities in having an abundance of heath shrubs, lichens, and bedrock outcrops. It differs by the predominance of pitch pine and probably by a more frequent or intense fire history, necessary to favor perpetuation of pitch pine over other trees. Pitch pine rocky ridges are similar to pitch pine - scrub oak woodlands in many ways, but are found in bedrock-controlled settings rather than on sand plains, and exhibit some differences in species composition. This community is rare in the New Hampshire, and rare or uncommon in other New England states and New York. It is found at both low (270 ft) and moderate (1,700 feet) elevations.
Drought and fire play an important role in the maintenance of pitch pine and other fire-adapted species found in this community. Return intervals of less than 50 years would tend to perpetuate pitch pine; longer return intervals could lead to more mixed composition, greater overall tree cover, and possible succession to other community types maintained by longer return intervals. Barren outcrops are common, ranging from 25–75% cover, forming small to large patches (<0.1 to 1+ acres) within this community. Without fire, a greater abundance of fire-intolerant species and tree cover in general can be expected in areas with soil cover. Xeric, barren outcrop areas may remain open for longer periods due to the amount of time required to build up soil.
Characteristic vegetation: Canopy composition ranges from nearly pure pitch pine to pitch pine co-dominating with a variable mix of other trees. Associated trees include pines, oaks, birches, and Picea rubens (red spruce). At low elevations (below 1,000 feet), Appalachian oaks and other southern species may be present, including Quercus alba (white oak), Q. montana (chestnut oak), Q. velutina (black oak), Q. prinoides (bear oak), and Sassafras albidum (sassafras). At higher elevations, Pinus resinosa (red pine) and red spruce can mix with pitch pine. Trees found at either elevation include Quercus rubra (red oak), Pinus strobus (white pine), Betula papyrifera (paper birch), B. populifolia (gray birch), and Acer rubrum (red maple).
Shrub cover is moderate (5–40%) and consists of low or dwarf shrubs; in places, extensive thickets of Quercus ilicifolia (scrub oak) form. Other common shrubs include Gaylussacia baccata (black huckleberry), Vaccinium angustifolium (lowbush blueberry), V. pallidum (hillside blueberry), Kalmia angustifolia (sheep laurel), Juniperus communis (ground juniper), Gaultheria procumbens (wintergreen), Sibbaldiopsis tridentata (three-toothed cinquefoil), Photinia melanocarpa (black chokeberry), and Amelanchier spp. (shadbush). At higher elevation sites, scrub oak and hillside blueberry are absent, and tall shrubs are limited to scattered individuals of other species.
Herbaceous cover is sparse, but a moderate diversity of grasses and sedges is typical. Deschampsia flexuosa (common hairgrass) and Pteridium aquilinum (bracken fern) are always present. Other frequent species include Comandra umbellata (bastard toadflax), Carex tonsa (shaved sedge), C. brevior (Fernald's sedge), Danthonia spicata (poverty oatgrass), Schizachyrium scoparium (little bluestem), Maianthemum canadense (Canada mayflower), Solidago puberula (downy goldenrod). Carex cumulata (piled-up sedge) is a rare plant documented from two examples; Nabalus serpentarius (gall-of-the-earth) is a rare herb found at one site. Lichens are common, growing extensively on and around barren rock outcrops, and include reindeer lichens (Cladonia spp.) which grow under and among heath shrubs.
This community differs from pitch pine - scrub oak woodlands on sand plains by having a greater abundance of lichens on thin soils and on rock outcrops, a higher frequency of common hairgrass, and at higher elevation sites, plants such as three-toothed cinquefoil, red pine, and red spruce.
Good examples of this community occur at
Pitch pine rocky ridges sometimes occur as part of larger temperate ridge - cliff - talus systems.
Pitch pine rocky ridge community in the Moose Mountains near Brookfield, NH (photo by Dan Sperduto)