Natural Communities of NH -- Photo Guide

Red oak - pine rocky ridge  (S3S4)

The red oak - pine rocky ridge community is the most common rocky ridge type between 1,000 and 2,000 feet elevation in southern and central New Hampshire, though it also occurs as high as 2,200 feet elevation on warm, south-facing slopes of the Saco River valley in the White Mountains.

This community is characterized by a scattered, moderately-short or stunted tree canopy of red oak (25-60% cover and 15-40 ft. tall), a significant short shrub layer (25-70% cover), and a usually sparse to moderately dense herb layer (<1-70% cover). Rock exposures generally cover 25-50% of the ground surface. These communities are fire-prone, and many examples have clear fire histories. Over the long-term, fire may be important for regenerating oak on these sites and it plays an important role in maintaining the structure, composition, and physical features of this community (e.g., shallow rocky soils with frequent outcrops). The open woodland structure and ridgeline positions often create good views at these sites, and they are therefore popular hiking destinations.

Ecologically, this community is very similar to Appalachian oak - pine rocky ridge and shares many of the same species. However, it is distinct by the absence of definitively southern and Appalachian species generally found below 1000-1300 ft., by the occasional presence of a few northern or higher elevation species, and by the prominence of red oak. Red oak is a broadly adapted temperate species, most abundant on dry sites where trees of mesic sites cannot survive. In New Hampshire, it grows well on mid-elevation ridges and mountains, while most other oaks become scarce above 1,000 feet.

Characteristic Vegetation: Characteristic trees include occasional to abundant red oak (Quercus rubra), red pine (Pinus resinosa), occasional pin cherry (Prunus pensylvanica), and infrequent red spruce (Picea rubens). White pine (Pinus strobus) is common. Frequent characteristic shrubs include lowbush blueberry (Vaccinium angustifolium) (nearly constant), velvet-leaf blueberry (V. myrtilloides), black huckleberry (Gaylussacia baccata), creeping juniper (Juniperus communis), bush honeysuckle (Diervilla lonicera), and sweet fern (Comptonia peregrina). Bearberry (Arctostaphylos uva-ursi) is infrequent on lower elevation examples. Characteristic and frequent herbaceous species include the lawn-forming distant sedge (Carex lucorum) as well as common hairgrass (Deschampsia flexuosa) (nearly constant), bracken (Pteridium aquilinum var. latiusculum), wintergreen (Gaultheria procumbens), pale corydalis (Corydalis sempervirens), poverty oatgrass (Danthonia spicata), little bluestem (Schizachyrium scoparium), Canada mayflower (Maianthemum canadense), silverrod (Solidago bicolor), cow wheat (Melampyrum lineare), and bronzy sedge (Carex foenea). Lichens and mosses are abundant on rocks. 

Species characteristic of this community that are notably absent from the Appalachian type include Douglas' knotweed (Polygonum douglasii), smooth sandwort (Minuartia glabra), American mountain ash (Sorbus americana), Drummond's tower mustard (Arabis drummondii), and three-toothed cinquefoil (Sibbaldiopsis tridentata). Appalachian trees and shrubs notably absent from or sparse in this community include pitch pine (Pinus rigida), oaks other than red oak, hickories, eastern red cedar (Juniperus virginiana), dangleberry (Gaylussacia frondosa), and sassafras (Sassafras albidum). Ironwood (Ostrya virginiana) may be present but are generally less abundant.

Higher elevation examples (1,400-1,900 ft.) appear to have more red spruce, three-toothed cinquefoil, and mountain ash, whereas lower elevation examples may have more southern species such as woodland sedge, creeping juniper, and false fern-leaved foxglove. Lower elevation examples have species such as fern-leaved false-foxglove, pink corydalis, and bearberry.  This community overlaps elevationally with red pine rocky ridges, with which it may sometimes intergrade. Red spruce and red pine increase above 1,700 feet, and may co-dominate with red oak in some areas.

Good examples of this community occur at Mt. Stanton (Bartlett), White Ledge (Albany), and Moat Mtn. (Conway).

Red oak - pine rocky ridges often occur as part of larger montane rocky ridge systems or temperate ridge - cliff - talus systems.

Red oak - pine rocky ridge at Ellis Hatch Wildlife Management Area (photo by Ben Kimball for the NH Natural Heritage Bureau)
Red oak - pine rocky ridge at Ellis Hatch Wildlife Management Area (photo by Ben Kimball)

Red oak - pine rocky ridge in the Ossipee Mountains (photo by Ben Kimball)
Red oak - pine rocky ridge in the Ossipee Mountains (photo by Ben Kimball)

Red oak and white pine in a red oak - white pine rocky ridge community (photo by Ben Kimball for the NH Natural Heritage Bureau)
Red oak and white pine in a red oak - pine rocky ridge community
(photo by Ben Kimball)

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