The Natural Communities of Virginia
Classification of Ecological Community Groups
SECOND APPROXIMATION (Version 2.2)
Acidic Oak - Hickory Forests
Forests in this group are similar to those of the Basic Oak-Hickory Forests, but occupy submesic to subxeric upland sites over
subacidic rocks such as siltstone, metasiltstone, shale, and certain granites. These forests are widely but locally distributed
throughout the Piedmont, inner Coastal Plain, mountain valleys, and lower mountain slopes of both the Blue Ridge and Ridge and Valley, up to about 600 m (2,000 ft) elevation. Hickories (
Carya spp.) are less abundant than in the Basic Oak-Hickory Forests group but are nevertheless prominent, often primarily as understory trees. Dominant oaks include white oak (
Quercus alba), black oak (
Quercus velutina), scarlet oak (
Quercus coccinea), southern red oak (
Quercus falcata), and chestnut oak (
Quercus montana, =
Quercus prinus).
Flowering dogwood (
Cornus florida) is a characteristic, often abundant understory tree, although its numbers have been greatly reduced in recent decades by the fungal pathogen dogwood anthracnose (
Discula destructiva). Deciduous ericads, especially lowbush blueberry (
Vaccinium pallidum) and deerberry (
Vaccinium stamineum), are usually present but patchy in the shrub layer, along with maple-leaved viburnum (
Viburnum acerifolium). Herbaceous diversity is somewhat less than in Basic Oak-Hickory Forests but considerably greater than in Oak/Heath Forests.
Typical herbs of these communities include plantain-leaf pussytoes (
Antennaria plantaginifolia), Pennsylvania sedge (
Carex pensylvanica), whorled coreopsis (
Coreopsis verticillata), poverty oat-grass (
Danthonia spicata), common dittany (
Cunila origanoides), rattlesnake-weed (
Hieracium venosum), large summer bluets (
Houstonia purpurea), low St. Andrew's cross (
Hypericum stragulum), whorled loosestrife (
Lysimachia quadrifolia), violet woodsorrel (
Oxalis violacea), gray beardtongue (
Penstemon canescens), solomon's-seal (
Polygonatum biflorum var. biflorum), lion's-foot (
Prenanthes serpentaria), wild pink (
Silene caroliniana ssp. pensylvanica), white goldenrod (
Solidago bicolor), wavy-leaved aster (
Symphyotrichum undulatum, =
Aster undulatus), and Carolina wood vetch (
Vicia caroliniana).
Acidic Oak-Hickory Forests are ecologically intermediate between species-rich Basic Oak-Hickory Forests and floristically
depauperate Oak/Heath Forests. They occupy less fertile soils and have lower species-richness and more ericaceous shrubs than do
Basic Oak-Hickory Forests. They are distinguished from Montane Oak-Hickory Forests by their restriction to low-elevation or
submontane habitats and corresponding composition consisting mostly of species that do not occur at higher elevations. Many
contemporary stands of Acidic Oak-Hickory Forests are suffering from the effects of fire exclusion, including poor oak recruitment
and the invasion of understories by fire-intolerant mesophytic species such as red maple (Acer rubrum), American beech
(Fagus grandifolia), and blackgum (Nyssa sylvatica).
References: Fleming (2002b), Fleming and Moorhead (2000), Fleming and Coulling (2001), Gemborys (1974), Olson and
Hupp (1986).
Click on the images below to open a larger image in a separate window.
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White oak (Quercus alba),
flowering dogwood (Cornus florida), and a patchy, graminoid-dominated herb layer are
characteristic of many acidic oak-hickory forests. Great Falls Park, Fairfax County.
Photo: Gary P. Fleming.
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Large-diameter black oak (Quercus velutina) in a southern Piedmont acidic oak-hickory forest. Near Union Hill, Buckingham County (Cumberland State Forest).
Photo: Gary P. Fleming.
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VANHP ecologists collecting plot data in a mature
acidic oak-hickory forest near South Fork Quantico Creek, Prince William Forest Park, Prince
William County.
Photo: Gary P. Fleming.
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REPRESENTATIVE COMMUNITY TYPES:
Classification of the Piedmont examples of this group is robust and well supported by plot data. Acidic
Oak-Hickory Forests of the western Virginia, while apparently widespread on shale and metasiltstone substrates, have not been adequately
sampled. The disposition of oak-hickory vegetation occurring on sandy uplands of the southeastern Virginia Coastal Plain is uncertain and
needs targeted investigation.
Click on any highlighted CEGL code below to view the global USNVC description provided by
NatureServe Explorer.
- Quercus alba – Quercus coccinea – Carya glabra / Cornus florida / Viburnum acerifolium
Forest
Northeastern Acidic Oak-Hickory Forest
USNVC:
= CEGL006336
Global/State Ranks:
G4G5/S4?
- Quercus alba – Quercus montana – Carya glabra / Cornus florida / Vaccinium pallidum / Carex pensylvanica Forest
Central Appalachian Acidic Oak-Hickory Forest
USNVC:
= CEGL008515
Global/State Ranks:
G4?/S4?
- Quercus alba – Quercus rubra – Carya ( alba , glabra ) / Cornus florida / Vaccinium stamineum Forest
Piedmont Acidic Oak-Hickory Forest
USNVC:
= CEGL008475
Global/State Ranks:
G5?/S4?
Quercus montana – (Quercus rubra) – Carya ssp. / Oxydendrum arboreum - Cornus florida Forest
Southern Appalachian Acidic Oak-Hickory Forest
USNVC:
= CEGL007267
Global/State Ranks:
G4G5/SNR
