Vegetation Classification and Mapping Project Report - USGS

USGS-NPS Vegetation Mapping Program
Colonial National Historical Park
Characteristic Species: Carex debilis (white edge sedge), Ilex decidua (possumhaw),
Liquidambar styraciflua (sweetgum), Quercus michauxii (swamp chestnut oak), Quercus pagoda
(cherrybark oak), Quercus phellos (willow oak).
Other Noteworthy Species: Information not available.
Subnational Distribution with Crosswalk Data:
State SRank Rel Conf SName
Reference
VA
SNR*
B
1
Non-Riverine Saturated Forest
Fleming et al. 2006
Local Range: Non-Riverine Saturated Forest occurs on a broad terrace near Powhatan Creek
and Green Spring. It is mapped as five polygons and covers a total of 53.4 hectares (132.0 acres).
Classification Comments: This forest is distinguished by its non-riverine landscape position
and the high frequency of hydric oaks and other characteristic herbaceous species.
Other Comments: Small areas of higher, drier forest may occur within areas mapped as Non-
Riverine Saturated Forest. Mature, undisturbed examples of this globally rare association are
uncommon. Only one polygon of this association in Colonial National Historical Park meets the
criteria to be considered a Natural Heritage exemplary natural community occurrence. Polygons
representing particularly disturbed examples are noted in the comment field of the map attribute
table.
Local Description Authors: K. D. Patterson.
Plots: COLO.18, COLO.28.
Colonial National Historical Park Inventory Notes: Information not available.
GLOBAL INFORMATION
USNVC CLASSIFICATION
Physiognomic Class Forest (I)
Physiognomic Subclass Deciduous forest (I.B.)
Physiognomic Group Cold-deciduous forest (I.B.2.)
Physiognomic Subgroup Natural/Semi-natural cold-deciduous forest (I.B.2.N.)
Formation Seasonally flooded cold-deciduous forest (I.B.2.N.e.)
Alliance Quercus phellos Seasonally Flooded Forest Alliance (A.330)
Alliance (English name) Willow Oak Seasonally Flooded Forest Alliance
Association Quercus (phellos, pagoda, michauxii) / Ilex opaca var. opaca / Clethra alnifolia
/ Woodwardia areolata Forest
Association (English name) (Willow Oak, Cherrybark Oak, Swamp Chestnut Oak) / American Holly /
Coastal Sweet-pepperbush / Netted Chainfern Forest
Ecological System(s): Northern Atlantic Coastal Plain Basin Swamp and Wet Hardwood Forest
(CES203.520).
GLOBAL DESCRIPTION
Concept Summary: This association occurs in the central and northern Virginia Coastal Plain
on extensive, flat terraces and very wide, ancient floodplains that are no longer subject to alluvial
processes. Its hydrology is seasonally to nearly permanently saturated, with occasional ponding
or groundwater sheetflows, and is maintained by a high water table rather than riverine or
estuarine flooding. The overstory of relatively undisturbed examples contain variable mixtures of
hydrophytic oaks, most commonly Quercus phellos (willow oak), Quercus pagoda (cherrybark
oak), and Quercus michauxii (swamp chestnut oak). Associated canopy species varying from site
to site can include Quercus alba (white oak), Quercus palustris (pin oak), Quercus lyrata
(overcup oak), Liquidambar styraciflua (sweetgum), Acer rubrum (red maple), Pinus taeda
(loblolly pine), Nyssa sylvatica (blackgum), and Fraxinus pennsylvanica (green ash). The
subcanopy layers are usually dominated by Ilex opaca var. opaca (American holly) and also
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