Coastal Plain Dry Calcareous Forests and Woodlands
This is a group of rare, deciduous (rarely mixed) forests and woodlands of subxeric to xeric, fertile habitats over unconsolidated, calcareous deposits. Similar forests are scattered in the mid-Atlantic Coastal Plain from Maryland to South Carolina. In Virginia, occurrences are small and highly localized in two environmental situations: 1) steep, convex, south-facing slopes of dissected ravine systems and river-fronting bluffs of the inner Coastal Plain from southeastern Virginia north to Stafford County; and 2) steep cut-slopes bordering estuaries on the outer Coastal Plain. In the first setting, slopes have downcut into Tertiary shell deposits or limesands, producing circumneutral to slightly alkaline soils. In the estuarine settings, shell middens may provide the primary source of substrate calcium. Calcium levels in soil samples collected from these habitats are among the highest documented in Virginia, ranging to > 11,000 ppm. The majority of documented stands are on The Peninsula near Williamsburg (James City and York Counties).
Tree canopies range from semi-closed to very open. Chinquapin oak (Quercus muehlenbergii) is the most characteristic tree; southern sugar maple (Acer floridanum), white oak (Quercus alba), northern red oak (Quercus rubra), bitternut hickory (Carya cordiformis), American beech (Fagus grandifolia), and white ash (Fraxinus americana) are common associates. In the stands bordering tidal streams, hackberries (Celtis occidentalis and Celtis laevigata) are characteristic components. The understory includes eastern red cedar (Juniperus virginiana var. virginiana), eastern redbud (Cercis canadensis var. canadensis), American holly (Ilex opaca var. opaca), buckthorn bumelia (Sideroxylon lycioides), and flowering dogwood (Cornus florida).
Although not lush, the herb layer contains a diversity of species, including several long-range mountain disjuncts. Particularly abundant or noteworthy herbaceous species include robin's-plantain (Erigeron pulchellus var. pulchellus), Bosc's panic-grass (Dichanthelium boscii), bearded shorthusk (Brachyelytrum erectum), white crownbeard (Verbesina virginica var. virginica), American bellflower (Campanula americana), hairy leafcup (Smallanthus uvedalius), whorled rosin weed (Silphium asteriscus var. trifoliatum), few-flowered tick-trefoil (Hylodesmum pauciflorum), crested coralroot (Hexalectris spicata var. spicata), hairy wild rye (Elymus villosus), and eastern needlegrass (Piptochaetium avenaceum). Compared to Basic Mesic Forests of the Coastal Plain, these dry calcareous forests have a larger component of oaks (particularly chinquapin oak) in the overstory and have a much less lush herb layer. The single Virginia community in this group is considered globally rare and are threatened by logging and development.References: Fleming (2002a).
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Coastal Plain Dry Calcareous Forest on a very steep, shell-rich bluff along the James River in Surry County.Gary P. Fleming / © DCR Natural Heritage.
Exposed Tertiary shell material on an erosive ravine convexity supporting Coastal Plain Dry Calcareous Forest. Near Williamsburg, James City County.Gary P. Fleming / © DCR Natural Heritage.
Large chinquapin oaks (Quercus muehlenbergii) in a graminoid-rich Coastal Plain Dry Calcareous Forest near Yorktown, York County (Colonial National Historical Park).Gary P. Fleming / © DCR Natural Heritage.