tidal hardwood swamps - Maryland Department of Natural Resources

FRAXINUS PROFUNDA – NYSSA BIFLORA / ILEX VERTICILLATA / POLYGONUM ARIFOLIUM TIDAL WOODLAND
Pumpkin Ash – Swamp Blackgum / Winterberry / Halberd-leaf Tearthumb Tidal Woodland
GLOBAL ELEMENT CODE CEGL006287
NATIONAL SYNONYM Equivalent to Fraxinus (profunda, pennsylvanica) – (Nyssa biflora) /
Polygonum arifolium Woodland [CEGL006287] of the USNVC.
Related in part to Acer rubrum - Fraxinus pennsylvanica /
Polygonum spp. Woodland [CEGL006165] of the USNVC.
TNC SYSTEM Terrestrial
PHYSIOGNOMIC CLASS Woodland
PHYSIOGNOMIC SUBCLASS Deciduous Woodland
PHYSIOGNOMIC GROUP Cold-deciduous Woodland
PHYSIOGNOMIC SUBGROUP Natural/Semi-natural
FORMATION Tidal Cold-deciduous Woodland
ALLIANCE Acer rubrum – Fraxinus pennsylvanica Tidal Woodland Alliance
ECOLOGICAL SYSTEM Atlantic Coastal Plain Northern Tidal Wooded
Swamp[CES203.282]
ENVIRONMENTAL DESCRIPTION
Tidal woodland characteristic of diurnally or irregularly flooded freshwater systems bordering the
upper reaches of Maryland’s coastal plain rivers and tributaries. Salt concentrations of nearby
waters are typically less than 0.5 ppt due to the dilution of tidal inflow from sufficient upstream
freshwater sources; however, spring high tides or low river discharge may result in pulses of
higher salinity. Development and persistence of these habitats is apparently limited downstream
by salinity gradients and upstream by the availability of sufficient sediment. Therefore, these
habitats are primarily associated with the upper end of the freshwater portion of the salinity
gradient. Typically, these woodlands form a physiognomically distinct zone on low floodplains
between dry, gradually sloping uplands and tidal emergent vegetation. Stand size is variable
ranging from small patches in to large (>40 hectares), linear stands. Pronounced hummock-andhollow
microtopography is characteristic of this community type. Hollows are regularly inundated
by tidal water, whereas hummocks are less frequently flooded thus supporting the establishment
of trees and mesophytic herbs. Soils are poorly drained slightly acidic tidal muck consisting of
variable amounts of silt or fine sands mixed with partially decomposed organic matter.
VEGETATION DESCRIPTION
This vegetation type belongs to a group of structurally complex woodlands with open (25-50%
cover) canopies and floristically diverse multiple lower strata. The canopy is dominated by
Fraxinus profunda, (10-25% cover), Nyssa biflora (5-10% cover) and Acer rubrum (10-25%
cover). Less frequent taxa may include Fraxinus pennsylvanica, Liquidambar styraciflua, Ulmus
americana and Pinus taeda. Although not distinct, the subcanopy is often comprised of trees
such as Fraxinus profunda, Acer rubrum, and tall shrubs of Magnolia virginiana. A dense and
remarkably diverse shrub stratum just below the subcanopy consistently includes species such as
Viburnum recognitum (5-10% cover) and Ilex verticillata (2-5% cover). Other notable taxa within
this stratum include Lindera benzoin, Viburnum nudum, Cornus amomum, Rhododendron
viscosum, Vaccinium corymbosum, Rosa palustris, Leucothoe racemosa, Clethra alnifolia and
Amelanchier canadensis. Less frequent shrubs include Ilex opaca, Alnus serrulata, Viburnum
prunifolium, Lyonia ligustrina, Morella cerifera (=Myrica cerifera), Photinia pyrifolia (=Aronia
arbutifolia), Cephalanthus occidentalis, Carpinus caroliniana and Itea virginica. Lianas and
herbaceous vines are common in multiple strata and include species such as Dioscorea villosa,
Toxicodendron radicans, Smilax rotundifolia, and Parthenocissus quinquefolia. Other less
abundant vines include Mikania scandens, Bignonia capreolata, Smilax laurifolia, Smilax walteri,
Clematis virginiana, and Mitchella repens. In addition to these species, non-native species such
as Clematis terniflora and Lonicera japonica can be locally abundant in light gaps and on stand
edges bordering open marshes and rivers. High species richness in the herb layer can be
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