Natural Communities of Virginia - Terrestrial System - Low-Elevation Dry and Dry - Mesic Forests and Woodlands: Ultramafic Woodlands

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

Ultramafic Woodlands
Vegetation of this group is confined to xeric uplands underlain by serpentinite, soapstone, talc-tremolite schist, and other ultramafic rocks. These naturally rare woodlands are only known from scattered locations in the mountains and Piedmont of Georgia, North Carolina, Virginia, Maryland, and Pennsylvania. Only five occurrences of these mixed woodlands are documented in Virginia: three in the Piedmont (Amherst, Franklin, and Nelson Counties) and two in The Glades region of the southern Blue Ridge plateau (Grayson County). Habitats are relatively gentle, rocky uplands with very dry, shallow, magnesium- and iron-rich soil. Ultramafic Woodlands, along with the closely related Ultramafic Barrens, are the only terrestrial communities documented in Virginia that grow in soils with Ca:Mg ratios < 1.

The original vegetation of the Piedmont examples was probably open, stunted savanna of post oak (Quercus stellata), blackjack oak (Quercus marilandica), and Virginia pine (Pinus virginiana) over little bluestem ((Schizachyrium scoparium). The present-day stands are semi-closed and more heavily dominated by Virginia pine as the result of disturbances such as cutting and fire exclusion. The Blue Ridge occurrences are open woodlands dominated by post oak, pitch pine (Pinus rigida), and eastern white pine (Pinus strobus), with a relatively dense herb layer containing little bluestem, big bluestem (Andropogon gerardii), balsam ragwort (Packera paupercula , = Senecio pauperculus), skunk meadowrue (Thalictrum revolutum) and other xerophytes. Also present are anomalous populations of several species more typical of wetland habitats, e.g ., Canada burnet (Sanguisorba canadensis) and pine-barren death-camas (Zigadenus leimanthoides).

These ultramafic woodlands are extremely rare in Virginia and globally. Quarrying has partly or wholly destroyed occurrences at two of the sites and poses a serious threat at another site. Additional threats to these communities include grazing, agriculture, and development.

Click on the images below to open a larger image in a separate window.

A remnant ultramafic woodland on talc-chlorite-tremolite schist in Franklin County. Photo: Irvine Wilson

REPRESENTATIVE COMMUNITY TYPES:
Data have been collected from three plots of the southern Blue Ridge examples and two plots of the Piedmont examples. It is unlikely that additional stands of this very rare vegetation will be found. Click on any highlighted CEGL code below to view the global USNVC description provided by NatureServe Explorer.

Pinus strobus – Pinus rigida – Quercus stellata / Ceanothus americanus / Andropogon gerardii – Packera paupercula Woodland
Southern Blue Ridge Ultramafic Woodland
USNVC: = CEGL004968
Global/State Ranks: G1/S1
Endemic
Pinus virginiana – Quercus stellata – Quercus marilandica / Schizachyrium scoparium Woodland (PROVISIONAL)
Piedmont Ultramafic Woodland
USNVC: no equivalent
Global/State Ranks: GNR/SNR

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

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