Dry Appalachian oak forest (S3)
(formerly dry Appalachian oak - hickory forest)
Dry Appalachian oak forests occur on dry, nutrient-poor, and well to extremely well drained soils of rocky hills and sand plains. This community is at the northernmost extent of its range in south-central New Hampshire, where it is primarily restricted to south-facing slopes. Red, white, black, and scarlet oak dominate the tree canopy, and hickories are sometimes present. Heath shrubs are the most abundant group of species in the understory, sometimes forming a dense shrub layer. Herbs are relatively sparse. The community is distinguished from dry red oak - white pine forests, which tend to lack significant representation of the southern or Appalachian species.
The ability of many oak species to root or stump sprout contributes to their perpetuation under regular fire regimes. Oak forests appear to be fire-dependant over long periods in other regions of the country. Some of these forests may succeed to other overstory species in time due to lack of adequate red oak regeneration, and from increases in beech on drier sites and sugar maple and beech on more mesic sites. Repeated fire would tend to knock back fire-sensitive species like beech and sugar maple. As such, any natural, semi-natural, and/or controlled fire regimes may be necessary for the long-term maintenance of oak on some sites.
These forests are typically found on middle and upper slopes of low hills with acidic, well to excessively drained soils of low available nutrient status (oligotrophic). They are also common on slopes with south or west aspects. Known or potential soil series include Hollis, Shapleigh, Brimfield, Charlton,
Characteristic Vegetation: Oaks include black oak (Quercus velutina), scarlet oak (Q. coccinea), white oak (Q. alba), chestnut oak (Q. montana), and red oak (Q. rubra). Hickories such as shagbark hickory (Carya ovata), sweet pignut hickory (C. ovalis), and pignut hickory (C. glabra) may be present but are typically less prevalent than the oaks, with red, white, and black oak being most common. White pine (Pinus strobus) is frequently present. Black birch (Betula lenta), red maple (Acer rubrum), sassafras (Sassafras albidum), and pitch pine (Pinus rigida) are occasional. Yellow birch (Betula alleghaniensis) tends to be more common on mesic sites. Any of the canopy species may exhibit local dominance, although the oaks are generally most abundant. Hemlock (Tsuga canadensis) occurs occasionally, although primarily as an understory tree, indicating its potential future prominence on some sites.
Shrub and herbaceous species that may be present (and which are generally characteristic of most dry acidic oak - pine forests) include ironwood (Ostrya virginiana), lowbush blueberry (Vaccinium angustifolium), hillside blueberry (V. pallidum), dangleberry (Gaylussacia frondosa), black huckleberry (G. baccata), maple-leaved viburnum (Viburnum acerifolium), sweet fern (Comptonia peregrina), witch hazel (Hamamelis virginiana), wintergreen (Gaultheria procumbens), Pennsylvania and woodland sedges (Carex pensylvanica/lucorum), common hairgrass (Deschampsia flexuosa), rough-leaved rice grass (Oryzopsis asperifolia), poverty oatgrass (Danthonia spicata), bracken (Pteridium aquilinum var. latiusculum), whorled loosestrife (Lysimachia quadrifolia), and pinweed (Lechea intermedia). Velvet-leaf blueberry (Vaccinium myrtilloides) and sheep laurel (Kalmia angustifolia) may also be occasional.
In addition to the characteristic shrubs and herbs mentioned above, several other southern species may occur, including Pennsylvania sedge (Carex pensylvanica), flowering dogwood (Cornus florida), mountain laurel (Kalmia latifolia), American hazelnut (Corylus americana), sweet goldenrod (Solidago odora), bronzy sedge (Carex foenea), plantain-leaved pussytoes (Antennaria plantaginifolia), wild indigo (Baptisia tinctoria), bird's-foot violet (Viola pedata), rattlesnake weed (Hieracium venosum), Canadian frostweed (Helianthemum canadense), bastard toadflax (Comandra umbellata), hairy bedstraw (Galium pilosum), slender mountain rice (Piptatherum pungens), slender ladies' tresses (Spiranthes lacera), fern-leaved false foxglove (Aureolaria pedicularia var. intercedens), reflexed sedge (Carex retroflexa), slender knotweed (Polygonum tenue), goat's rue (Tephrosia virginiana), Maryland tick trefoil (Desmodium marilandicum), and prostrate tick trefoil (Desmodium rotundifolium). Dwarf chestnut oak (Quercus prinoides) and scrub oak (Q. ilicifolia) are occasional.
This community typically has a strong heath understory while herbaceous species are infrequent. In some examples, however, heath shrubs may be scarce while herbs, grasses, and sedges are more prominent, though such dry-mesic, less acidic examples may grade into the semi-rich oak - sugar maple forest community.
Good examples of this community can be seen at
Dry Appalachian oak forests often occur as part of larger Appalachian oak - pine forest systems or temperate ridge - cliff - talus systems.
Dry Appalachian oak forest at Madame Sherri Forest in Chesterfield (photo by Ben Kimball)
Dry Appalachian oak forest inside a meander along the Merrimack River (photo by Ben Kimball)