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NATURAL HERITAGE

The Natural Communities of Virginia
Classification of Ecological Community Groups
SECOND APPROXIMATION (Version 2.2)

Oak – Hickory Woodlands and Savannas
Piedmont military base training areas (“impact areas”) that have been subject to frequent incendiary fires for at least 50 years support the deciduous woodlands that constitute this group. As currently defined, these communities are endemic to Virginia and are now found only at Quantico Marine Base in the northern Piedmont (Fauquier, Prince William, and Stafford Counties) and Fort Pickett in the southern Piedmont (Dinwiddie and Nottoway Counties), where they cover hundreds of hectares. Habitats at both sites are rolling uplands underlain by granitic rocks. Soils are generally sandy and range from extremely to strongly acidic, with relatively low base cation levels. However, in a small (20-25 ha) area of Fort Pickett that is underlain by a sill of intrusive Triassic diabase, soils are dark, slightly acidic to circumneutral loams with relatively high calcium and magnesium levels.

Stand physiognomy encompasses semi-closed woodlands with little understory; graminoid-rich savannas with widely spaced trees; and dense thickets of small, sprout-origin trees. Variable mixtures of white oak (Quercus alba), black oak (Quercus velutina), southern red oak (Quercus falcata), scarlet oak (Quercus coccinea), post oak (Quercus stellata), and mockernut hickory (Carya alba) form the woodland overstories. Understories are highly variable in both density and composition. Dense herb layers are rich in both grasses and legumes. Abundant species include little bluestem (Schizachyrium scoparium), indian grasses (Sorghastrum nutans and Sorghastrum elliottii), broomsedges (Andropogon virginicus var. virginicus) and (Andropogon gyrans), poverty oat-grass (Danthonia spicata), silver plumegrass (Saccharum alopecuroidum), tick-trefoils (Desmodium spp.), and lespedezas Lespedeza spp.). Goldenrods (Solidago spp.), thoroughworts (Eupatorium spp.), and other composites are characteristic of the diverse late-flowering flora of the woodlands. Stands on basic soil have a more species-rich herbaceous flora characterized by forbs, including nettle-leaf sage (Salvia urticifolia), glade wild quinine (Parthenium auriculatum), naked-flowered tick-trefoil (Desmodium nudiflorum), green-and-gold (Chrysogonum virginianum var. virginianum), perfoliate bellwort (Uvularia perfoliata), sunflowers (Helianthus strumosus and (Helianthus divaricatus), lesser snakeroot (Ageratina aromatica var. aromatica), skunk meadowrue (Thalictrum revolutum), and hog-peanut (Amphicarpaea bracteata).

Although communities of this group are strongly influenced by an artificial disturbance regime, they are Virginia's only extant examples of vegetation that is shaped by random burns of a size, frequency, and intensity comparable to those of putative pre-settlement fire regimes. Thus, they may provide important clues about the probable composition and environmental dynamics of woodlands that burned under a regime of natural fires and fires intentionally set by native Americans beginning in the early Holocene. The largest known population in the world of the globally rare, federally listed shrub Michaux's sumac (Rhus michauxii) is associated with the fire-influenced woodlands at Fort Pickett.

References: Fleming (2002a), Maxwell (1910).


Click on the images below to open a larger image in a separate window.
Nettle-leaf sage (Salvia urticifolia , flowering), woodland sunflower (Helianthus divaricatus), and hickory (Carya sp.) saplings in a Basic Oak-Hickory Woodland / Savanna on diabase at Fort Pickett Military Reservation, Dinwiddie County. Photo: Gary P. Fleming.
Fire-maintained, graminoid-rich Acidic Oak-Hickory Woodland / Savanna at Quantico Marine Base, Fauquier County. Photo: Gary P. Fleming.
A frequently burned savanna dominated by oaks (Quercus spp.), hickories (Carya spp.), and little bluestem (Schizachyrium scoparium) at Fort Pickett Military Reservation, Dinwiddie County. Photo: Caren Caljouw.
REPRESENTATIVE COMMUNITY TYPES:
The two classified community types are represented by five and seven plots, respectively. It is unlikely that additional stands will be found outside of the two military bases where this group is known to occur. Click on any highlighted CEGL code below to view the global USNVC description provided by NatureServe Explorer.

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Table of Contents

Introduction

Overview of VA Physiography & Vegetation

Glossary

Literature

Format of Descriptions

Terrestrial System: LOW-ELEVATION DRY AND DRY- MESIC FORESTS AND WOODLANDS
   - Dry-Mesic Calcareous Forests
   - Basic Oak - Hickory Forests
   - Acidic Oak - Hickory Forests
   - Montane Mixed Oak & Oak-Hickory Forests
   - Oak / Heath Forests
   - Eastern White Pine - Hardwood Forests
   - Piedmont / Coastal Plain Oak – Beech / Heath Forests
   - Carolina Hemlock Forests
   - Pine – Oak / Heath Woodlands
   - Mountain / Piedmont Acidic Woodlands
   - Mountain / Piedmont Basic Woodlands
   - Ultramafic Woodlands
   - Montane Dry Calcareous Forests and Woodlands
   - Coastal Plain Dry Calcareous Forests and Woodlands
   - Oak – Hickory Woodlands and Savannas
   - Piedmont Hardpan Forests
   - Low-Elevation Boulderfield Forests

Palustrine System

Riverine System

Estuarine System

Marine System