Piedmont guide




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PIEDMONT GUIDE

March 2003


Piedmont and Coastal Plain Mesic Forests
PIEDMONT/COASTAL PLAIN HEATH BLUFF G 2?/G2G3

Synonyms: Fagus grandifolia-Quercus prinus-Quercus alba/Kalmia latifolia-(Rhododendron catawbiense) Forest (4539). Quercus prinus _ Quercus alba / Oxydendrum arboreum / Kalmia latifolia Forest (4415)?


Concept: Type covers communities of cool microsites in the Piedmont and Coastal Plain, generally north-facing bluffs, with dense shrub layers dominated by Kalmia latifolia or Rhododendron catawbiense under a variable, usually open canopy.
Distinguishing Features: Piedmont/Coastal Plain Heath Bluff is distinguished from Mesic Mixed Hardwood Forest by having a dense shrub layer dominated by Kalmia latifolia or Rhododendron sp. The species diversity is generally very low. These communities may grade conceptually into Acidic Cove Forests in the upper Piedmont, with Rhododendron maximum becoming a more prominent component and more montane flora being present. Substantial presence of Tsuga canadensis, Betula lenta, Halesia tetraptera, or Liriodendron tulipifera, predominating over Quercus montana, Quercus alba, or Fagus grandifolia, indicates Acidic Cove Forest.
Comments: Fagus grandifolia-(Liquidambar styraciflua)/Oxydendrum arboreum/Kalmia latifolia Forest (4636) is a non-standard entity in the NVC, based on Rice and Peet’s Roanoke River study. It is not clear that Roanoke River examples or most Coastal Plain examples are distinct from those in the Piedmont. However, some Coastal Plain examples contain a larger component of characteristic Coastal Plain species, usually including some wetland that apparently are associated with seepage from the steep bluffs.
These communities occur in Virginia, but in much of Virginia Piedmont Kalmia latifolia is more widespread, is not confined to cool microsites, and this community loses its distinctness. The same thing may happen in the westernmost Piedmont in North Carolina, and possibly in the Uwharrie Mountains. 4415 may represent this.

MESIC MIXED HARDWOOD FOREST (COASTAL PLAIN SUBTYPE)

Synonyms: Fagus grandifolia-Quercus nigra Forest (7211)
Concept: Type covers mesic hardwood forests of acidic bluffs and other fire-sheltered sites in the Piedmont and Coastal Plain, dominated by combinations of Fagus grandifolia, Quercus nigra, Liriodendron tulipifera, Quercus rubra, or species of similar moisture tolerance but lacking the more diverse components of Rich Cove Forest or Acidic Cove Forest. Some component of Quercus alba, Quercus michauxii, or other species of more dry or more wet sites may be intermixed.

Subtype covers Coastal Plain examples, where Quercus rubra is generally absent and Quercus nigra or Quercus alba are frequently components. They may occur on steep north-facing bluffs, on moist upland flats associated with nonriverine wetlands, or on mesic ridges within river floodplains. A few examples with more Piedmont-like flora may occur in the northern Coastal Plain.


Distinguishing Features: The Mesic Mixed Hardwood Forest type is distinguished by a canopy dominated by mesic hardwoods while lacking indicators of higher pH soils and of flooding and lacking significant montane flora. Fagus grandifolia is nearly always present and distinguishes it from all related communities except Basic Mesic Forest, Beech Bottoms, Acidic Cove Forest, and Rich Cove Forest. Mesic Mixed Hardwood Forest may be distinguished from [Beech Bottoms] by lacking any significant component of floodplain species or indicators of flooding. It may be distinguished from Basic Mesic Forest by lower species richness and by lacking the species that in the Piedmont and Coastal Plain are indicators of higher pH soils. Such indicators are primarily herbs. Species include Cimicifuga racemosa, Asarum canadense, Adiantum pedatum, Sanguinaria canadensis, Hybanthus concolor, and Actaea pachypoda. Ostrya virginiana, Carpinus caroliniana, Fraxinus americana, Aesculus sylvatica, and Aesculus pavia tend to be common in Basic Mesic Forest and scarce in Mesic Mixed Hardwood Forest.
The Coastal Plain Subtype is distinguished from the Piedmont Subtype by flora, which includes a predominance of species typical of the Coastal Plain over those typical of the Piedmont, though many species are shared and some Piedmont species occur as disjuncts within the Coastal Plain. Coastal Plain indicators include Quercus nigra, Stewartia malacodentron, Symplocos tinctoria, Gaylussacia frondosa, .... Piedmont indicators include Quercus rubra, ....
Comments: Three variants are distinguished, which may warrant treatment as separate associations: bluff/slope, swamp island, and upland flat. Fagus grandifolia-Quercus alba-Quercus laurifolia/Galax urceolata Forest (7863) has been described for Virginia and could possibly occur in NC. Fagus grandifolia-Liquidambar styraciflua-Quercus (michauxii, nigra) forest (7866) is a Coastal Plain small stream bottom association of South Carolina and Georgia. Peet has assigned plots from the Roanoke River floodplain to it. Fagus grandifolia-Quercus alba-Liriodendron tulipifera-Carya spp. Forest (6075) is a Coastal Plain mesic forest of northern Virginia and northward, but is not expected to occur in North Carolina.

MESIC MIXED HARDWOOD FOREST (PIEDMONT SUBTYPE)

Synonyms: Fagus grandifolia-Quercus rubra/Cornus florida/Polystichum acrostichoides-Hexastylis virginica Forest (8465).
Concept: Type covers mesic hardwood forests of acidic bluffs and other fire-sheltered sites in the Piedmont and Coastal Plain, dominated by combinations of Fagus grandifolia, Quercus nigra, Liriodendron tulipifera, Quercus rubra, or species of similar moisture tolerance but lacking the more diverse components of Rich Cove Forest or Acidic Cove Forest. Some component of Quercus alba, Quercus michauxii, or other species of more dry or more wet sites may be intermixed.

Subtype covers Piedmont examples, where Quercus rubra and other characteristic Piedmont species are present and characteristic Coastal Plain species are absent.


Distinguishing Features: The Mesic Mixed Hardwood Forest type is distinguished by a canopy dominated by mesic hardwoods while lacking indicators of higher pH soils and of flooding and lacking significant montane flora. Fagus grandifolia is nearly always present and distinguishes it from all related communities except Basic Mesic Forest, Beech Bottoms, Acidic Cove Forest, and Rich Cove Forest. Mesic Mixed Hardwood Forest may be distinguished from [Beech Bottoms] by lacking any significant component of floodplain species or indicators of flooding. It may be distinguished from Basic Mesic Forest by lower species richness and by lacking the species that in the Piedmont and Coastal Plain are indicators of higher pH soils. Such indicators are primarily herbs. Species include Cimicifuga racemosa, Asarum canadense, Adiantum pedatum, Sanguinaria canadensis, Hybanthus concolor, and Actaea pachypoda. Ostrya virginiana, Carpinus caroliniana, Fraxinus americana, Aesculus sylvatica, and Aesculus pavia tend to be common in Basic Mesic Forest and scarce in Mesic Mixed Hardwood Forest. Many of the same indicators are present in Rich Cove Forest, as well as a number of other montane species such as Aesculus flava, Tilia americana var. heterophylla, Halesia tetraptera, and Betula lenta, and their absence distinguishes Mesic Mixed Hardwood Forest from that type. Mesic Mixed Hardwood Forest may be distinguished from Acidic Cove Forest by the absence of montane species, though the set of species is limited to the more acid tolerant ones such as Betula lenta, Tsuga canadensis, Rhododendron maximum, and Leucothoe fontanesiana.
The Piedmont Subtype is distinguished from the Coastal Plain Subtype by flora, which includes a predominance of species typical of the Coastal Plain over those typical of the Piedmont, though many species are shared and some Piedmont species occur as disjuncts within the Coastal Plain. Coastal Plain indicators include Quercus nigra, Stewartia malacodentron, Symplocos tinctoria, Gaylussacia frondosa, .... Piedmont indicators include Quercus rubra, .... Some samples may contain only widespread species and may be more readily distinguished by geographic location.
Comments: Virginia has this association in the Coastal Plain as well as the Piedmont.

MESIC MIXED HARDWOOD FOREST (PIEDMONT BOTTOMLAND SUBTYPE)

Synonyms: Fagus grandifolia-Acer barbatum/Asimina triloba/Toxicodendron radicans/Carex blanda Forest (7321).
Concept: Subtype covers beech-dominated forests of high areas on Piedmont floodplains, where flooding occurs but is of short duration and soils are alluvial.
Distinguishing Features: The Piedmont Bottomland Subtype is distinguished from the Piedmont Bluff Subtype by occurring on floodplain terraces or high natural levees, where short term flooding occurs.

MESIC MIXED HARDWOOD FOREST (?? SUBTYPE)

Synonyms: Fagus grandifolia-Quercus spp./Kalmia latifolia-Hamamelis virginiana/Galax urceolata Forest (4549).
Concept: Uwharries?

BASIC MESIC FOREST (COASTAL PLAIN SUBTYPE)

Synonyms: Fagus grandifolia-Quercus alba-( Acer barbatum)/Mixed Herbs Forest (7206).
Concept: Type covers mesic forests of circumneutral or higher pH soils in the Piedmont and Coastal Plain, occurring on bluffs or other fire-sheltered sites, and dominated by combinations of Fagus grandifolia, Quercus nigra, Liriodendron tulipifera, Quercus rubra, and species of similar moisture tolerance. Subtype covers examples in the Coastal Plain, occurring on rich, well-drained alluvium or around limestone outcrops.
Distinguishing Features: The Basic Mesic Forest type is distinguished by the combination of a canopy of mesic hardwoods and the presence of indicators of higher pH soils, along with the absence of montane species that would indicate Rich Cove Forest. The Coastal Plain Subtype is distinguished by occurring on Coastal Plain sediments, either rich alluvium or soils derived from limestone, and by floristic differences. Plants present in the Coastal Plain Subtype and lacking in the Piedmont Subtype include....
Comments: There are two distinct variants of this subtype, on soils around limestone outcrops and on rich alluvial terrace slopes. These may warrant separate associations.

BASIC MESIC FOREST (PIEDMONT SUBTYPE)

Synonyms: Fagus grandifolia-Quercus rubra/Ostrya virginiana-Acer barbatum/Adiantum pedatum-Sanguinaria canadensis (8466).
Concept: Type covers mesic forests of circumneutral or higher pH soils in the Piedmont and Coastal Plain, occurring on bluffs or other fire-sheltered sites, and dominated by combinations of Fagus grandifolia, Quercus nigra, Liriodendron tulipifera, Quercus rubra, and species of similar moisture tolerance. Subtype covers examples in the Piedmont, occurring on mafic rock substrates and lacking characteristic Coastal Plain flora.
Distinguishing Features: The Basic Mesic Forest type is distinguished by the combination of a canopy of mesic hardwoods and the presence of indicators of higher pH soils, along with the absence of montane species that would indicate Rich Cove Forest. The Piedmont Subtype is distinguished by occurring on crystalline rock substrates and by floristic differences. Plants present in the Coastal Plain Subtype and lacking in the Piedmont Subtype include....
Comments: There are two recognized variants which differ in amount of apparent basic influence. The intermediate variant contains only the more widespread and broadly tolerant circumneutral plant species such as Adiantum pedatum, Sanguinaria canadensis, Podophyllum peltatum, and Cimicifuga racemosa. The basic variant includes these, but also includes more narrowly tolerant basic plant species such as Hybanthus concolor, Mertensia virginica, and Aquilegia canadensis. These may be worthy of recognition as associations.
Piedmont and Coastal Plain Dry and Dry-Mesic Hardwood Forests
DRY-MESIC OAK--HICKORY FOREST (PIEDMONT SUBTYPE)

Synonyms: Quercus alba-Quercus (rubra, coccinea)-Carya (glabra, alba)/Vaccinium (stamineum, pallidum) Forest (8475).


Concept: Type covers dry-mesic forests of acidic upland slopes and somewhat sheltered ridges in the Piedmont and Coastal Plain, dominated by combinations of Quercus alba, Quercus rubra, Quercus velutina, Carya alba, Carya glabra, along with varying amounts of pine, maple, and poplar. Basic soil plants are absent or scarce, and acid tolerant species such as Oxydendrum arboreum and Vaccinium spp. are common. These forests cover the moisture range between that where Fagus becomes a significant component and that where Quercus falcata, Quercus stellata, Quercus marilandica, or Quercus montana become significant components. Subtype covers Piedmont examples, which lack characteristic Coastal Plain species.
Distinguishing Features: The Dry-Mesic Oak--Hickory Forest type is distinguished from Basic Oak--Hickory Forests by having flora characteristic of acidic soils, such as Oxydendrum arboreum, Vaccinium stamineum, Vaccinium pallidum, Vaccinium tenellum, Gaylussacia frondosa, and Chimaphila maculata. Species restricted to more basic soils, such as Cercis canadensis, Fraxinus americana, Ostrya virginiana, ... are absent or scarce and low in diversity. Viburnum rafinesquianum and other Viburnum species may be present but are not dominant shrubs. Dry-Mesic Oak--Hickory Forest is distinguished from Dry Oak--Hickory Forest by a flora of more mesic composition, most clearly in the canopy. Quercus stellata, Quercus falcata, Quercus marilandica, and Quercus montana are scarce or absent. It is distinguished from Mesic Mixed Hardwood Forest by the absence of more mesic species, particularly Fagus grandifolia. It is distinguished from Montane Oak--Hickory Forest by the absence of characteristically montane flora, such as Castanea dentata, Magnolia fraseri, Acer pennsylvanicum, Rhododendron calendulaceum, and Rhododendron maximum. Additionally, some species are widespread in Montane Oak--Hickory Forests but are restricted to more mesic communities than this in the Piedmont and Coastal Plain. These include Kalmia latifolia, Hamamelis virginiana, Polygonatum biflorum.

The Piedmont Subtype is distinguished from the Coastal Plain Subtype by floristic differences. Quercus rubra, ... are largely restricted to the Piedmont Subtype. Quercus nigra, Gaylussacia frondosa, Ilex glabra, Myrica cerifera, Arundinaria gigantea var. tecta are largely restricted to the Coastal Plain Subtype.


Comments: This association is perhaps the most common one in the Piedmont. It is also common in Virginia, where Quercus coccinea becomes more common than Quercus rubra as a component. It extends across the Coastal Plain in northern Virginia.


DRY-MESIC OAK--HICKORY FOREST (COASTAL PLAIN SUBTYPE)

Synonyms: Quercus alba-Carya alba/Vaccinium elliottii Forest (7224). Quercus alba-Carya glabra/Mixed Herbs Coastal Plain Forest (7226). Quercus alba-Quercus nigra-Quercus falcata/Ilex opaca/Clethra alnifolia-Arundinaria gigantea var. tecta Forest (7862).
Comments: The NVC contains 3 associations comparable to this subtype. It is unclear how they differ, which actually occur in North Carolina, whether they are even all distinct from each other, and whether the Coastal Plain examples in North Carolina are different enough from the Piedmont examples to warrant a separate subtype.

DRY OAK–HICKORY FOREST (PIEDMONT SUBTYPE)

Synonyms: Quercus falcata-Quercus alba-Carya alba/Oxydendrum arboreum/Vaccinium stamineum Forest (7244).
Concept: Type covers upland hardwood forests of acidic soils in the driest typical topographic positions, on south slopes and ridge tops; where Quercus alba, Q. stellata, and Q. falcata predominate in the canopy. They are less xeric in composition than the Quercus stellata-Q. marilandica forests that occur in specialized edaphic conditions such clay hardpans, shallow rock, or very sandy soils. They contain acid-tolerant flora such as Oxydendrum arboreum, Nyssa sylvatica, Vaccinium stamineum, Vaccinium pallidum, and Vaccinium arboreum, and lack more base-loving plants. Subtype covers typical examples of the Piedmont, which lack significant Coastal Plain flora.
Distinguishing Features: Dry Oak–Hickory Forests are distinguished from Basic Oak–Hickory Forests by having acid-tolerant plants predominating and lacking more base-loving plants. This is most apparent in the lower strata, but the number of distinguishing species is less than in more mesic communities because of the limited number of species present. Oxydendrum arboreum, Vaccinium pallidum, Vaccinium tenellum, and Chimaphila maculata are generally absent in Basic Oak–Hickory Forest. Cercis canadensis, Fraxinus americana, and Viburnum spp. are generally abundant in Basic Oak–Hickory Forest and scarce in Dry Oak–Hickory Forest. Dry Oak–Hickory Forests are distinguished from Dry-Mesic Oak–Hickory Forests by canopy composition, which has Quercus stellata, Q. falcata, and other trees more drought-tolerant than Quercus alba predominating over Quercus rubra and other trees less drought-tolerant than Quercus alba. It is distinguished from Xeric Hardpan Forest by a canopy which contains significant Quercus alba and other trees that are less xerophytic than Quercus stellata and Q. marilandica.

The Piedmont Subtype is distinguished by....


Comments: As currently defined in the NVC, this association is very broad and not precisely defined, extending to Mississippi and Kentucky. It apparently excludes the Atlantic Coastal Plain. It apparently does not occur in Virginia, where drier sites are occupied by an oak/heath forest of more northerly affinities.
DRY OAK–HICKORY FOREST (COASTAL PLAIN SUBTYPE)

Synonyms: Quercus stellata-Quercus falcata-Carya alba/Vaccinium spp. Coastal Plain Forest (7246).


Concept: Type covers upland hardwood forests of acidic soils in the driest typical topographic positions, on south slopes and ridge tops; where Quercus alba, Q. stellata, and Q. falcata predominate in the canopy. They are less xeric in composition than the Quercus stellata-Q. marilandica forests that occur in specialized edaphic conditions such clay hardpans, shallow rock, or very sandy soils. They contain acid-tolerant flora such as Oxydendrum arboreum, Nyssa sylvatica, Vaccinium stamineum, Vaccinium pallidum, and Vaccinium arboreum, and lack more base-loving plants. Subtype covers Coastal Plain examples with different floristic composition.
Distinguishing Features: Dry Oak–Hickory Forests are distinguished from Basic Oak–Hickory Forests by having acid-tolerant plants predominating and lacking more base-loving plants. This is most apparent in the lower strata, but the number of distinguishing species is less than in more mesic communities because of the limited number of species present. Oxydendrum arboreum, Vaccinium pallidum, Vaccinium tenellum, and Chimaphila maculata are generally absent in Basic Oak–Hickory Forest. Cercis canadensis, Fraxinus americana, and Viburnum spp. are generally abundant in Basic Oak–Hickory Forest and scarce in Dry Oak–Hickory Forest. Dry Oak–Hickory Forests are distinguished from Dry-Mesic Oak–Hickory Forests by canopy composition, which has Quercus stellata, Q. falcata, and other trees more drought-tolerant than Quercus alba predominating over Quercus rubra and other trees less drought-tolerant than Quercus alba. It is distinguished from Xeric Hardpan Forest by a canopy which contains significant Quercus alba and other trees that are less xerophytic than Quercus stellata and Q. marilandica.
Comments: A northern Coastal Plain association, Quercus (falcata, alba, velutina)/Gaylussacia baccata-Vaccinium pallidum Forest (6269), is attributed to North Carolina and may occur in the northernmost Coastal Plain. This needs to be clarified.

DRY OAK–HICKORY FOREST (LOBLOLLY PINE SUBTYPE OR PHASE?)

Synonyms: Pinus taeda-Quercus (alba, falcata, stellata) Forest (Placeholder) (4766).

Concept: Pine-codominated Dry Oak–Hickory Forests occur in successional situations where pines became established in response to heavy cutting. Pine likely occur naturally as a minority component in most Dry Oak–Hickory Forests. Natural pine-hardwood forests of this composition also occur in the Gulf Coastal Plain. It is unclear if natural forests codominated by pine would occur in the North Carolina Coastal Plain.


Pinus taeda-Quercus falcata/Vaccinium pallidum/Hexastylis arifolia Forest (6033) has been defined in Virginia and not attributed to North Carolina. It is unclear how it relates to this.

DRY-MESIC BASIC OAK–HICKORY FOREST (PIEDMONT INTERMEDIATE SUBTYPE)

Synonyms: Quercus rubra-Quercus alba-Carya glabra/Geranium maculatum Forest (7237).
Concept: Type covers dry-mesic Piedmont and Coastal Plain forests with less acidic and more fertile soils than typical, associated with mafic or intermediate crystalline rocks or occasionally calcareous sedimentary rocks. They are equivalent in moisture regime to Dry-Mesic Oak–Hickory Forest, and fall between Basic Mesic Forest and Dry Basic Oak–Hickory Forest. Subtype covers examples that are less basic and fertile, as indicated by floristic composition.
Distinguishing Features: The Dry-Mesic Basic Oak–Hickory Forest type is distinguished from Basic Mesic Forest by a drier flora. The canopy is dominated by oaks and hickory, with essentially no Fagus grandifolia in the canopy. It is distinguished from Dry Basic Oak–Hickory Forest by having few or none of the drier site oaks -- Quercus stellata, Quercus marilandica, or Quercus falcata. It is distinguished from Dry-Mesic Oak–Hickory Forest by occurrence of more base-loving flora in association with less acidic substrate. Heaths, at least the more acid-loving ones such as Oxydendrum arboreum, Vaccinium pallidum, and Vaccinium tenellum, are absent. Fraxinus americana, Acer leucoderme, Ostrya virginiana, Cercis canadensis, and Viburnum spp. may be abundant. Carya spp. are more abundant than in Dry-Mesic Oak–Hickory Forest. The Piedmont Intermediate Subtype is distinguished by a flora that largely lacks the acid-loving species but has fewer of the more base-loving species.
Comments: The distinction between this subtype and the Piedmont Basic Subtype is based on such a distinction shown by data analysis in Virginia. It has not yet been shown to exist in North Carolina. As the classification stands now, it is a finer split than is made in other Piedmont hardwood forests, and may not be warranted.

The Virginia analysis also showed that, although the flora was that typically associated with less acidic conditions, soil pHs were in the range of 5.5 to 7 rather than truly basic. Cation amounts and pHs were, however, greater than in acidic communities.

DRY-MESIC BASIC OAK–HICKORY FOREST (PIEDMONT BASIC SUBTYPE)

Synonyms: Quercus alba-Carya ovata/Cercis canadensis Forest (7232). Quercus alba _ Quercus rubra _ Carya glabra _ Carya ovata / Viburnum rafinesquianum / Viola tripartita Forest (7236).

Concept: Subtype covers examples with a strong basic flora component.
Distinguishing Features: The Basic Subtype is distinguished by having a flora with more base-loving species such as Cimicifuga racemosa, Polygala senega, and Matelea decipiens. The species richness is also higher, with many herbs and sometimes abundant vines.
Comments: It is unclear if the two NVC associations represent a distinction of communities or an overlapping concept.

DRY-MESIC BASIC OAK–HICKORY FOREST (UWHARRIE GORGE SUBTYPE)

Synonyms: Quercus alba-Quercus rubra-Quercus prinus-Tilia americana var. caroliniana/Ostrya virginiana (4542).
Concept: An odd community that contains mostly dry-site species, with a few weedy and alluvial species, but which apparently occurs on alluvial terraces.

DRY-MESIC BASIC OAK–HICKORY FOREST (COASTAL PLAIN SUBTYPE)

Synonyms: Quercus alba-Carya glabra-Carya alba/Aesculus pavia Forest (7225).
Concept: Subtype covers the rare Coastal Plain examples.
Comments: This NVC association is unclearly defined, and it may not fit our examples well.

DRY BASIC OAK–HICKORY FOREST (PIEDMONT SUBTYPE)

Synonyms: Quercus alba-Quercus stellata-Carya carolinae-septentrionalis/Acer leucoderme-Cercis canadensis Forest (7773).
Concept: Type covers dry Piedmont and Coastal Plain forests with less acidic and more fertile soils than typical, associated with mafic or intermediate crystalline rocks or occasionally calcareous sedimentary rocks. They are associated with dry topographic positions but not with more extreme dry situations created by edaphic conditions such as clay hardpans, shallow rock, or excessive drainage. Subtype covers the typical examples of the Piedmont.
Distinguishing Features: The Dry Basic Oak–Hickory Forest type is distinguished from Dry-Mesic Basic Oak–Hickory Forest by having a drier flora, with a canopy containing substantial amounts of Quercus stellata, Quercus falcata, or Quercus marilandica, along with abundant Quercus alba, and lacking substantial Quercus rubra. It is distinguished from Xeric Hardpan Forest by occurring on less extreme soils and having a less xerophytic canopy. Quercus alba is generally the most abundant tree in Dry Basic Oak–Hickory Forest and is a minor component in Xeric Hardpan Forest. Dry Basic Oak–Hickory Forest is distinguished from Dry Oak–Hickory Forest, which occurs in similar topographic settings and moisture regimes, by the presence of base-loving flora and the absence or scarcity of the most acid-loving plants.
Comments: These three associations all seem to fall within the range of this subtype, and it is not clear how they are differentiated from each other, or that they are even distinct. Oxydendrum arboreum, Vaccinium pallidum, and Vaccinium tenellum, are absent. Fraxinus americana, Acer leucoderme, Ostrya virginiana, Cercis canadensis, and Viburnum spp. may be abundant. Carya spp. and Juniperus virginiana are more abundant than in Dry-Mesic Oak–Hickory Forest.

DRY BASIC OAK–HICKORY FOREST (UWHARRIE BOULDERFIELD SUBTYPE)

Synonyms: Quercus alba-Carya glabra-Fraxinus americana/Acer leucoderme/Vitis rotundifolia Forest (4541)

CHESTNUT OAK FOREST (PIEDMONT MONADNOCK SUBTYPE)

Synonyms: ???
Concept: Subtype covers examples on monadnocks in the eastern and central Piedmont, lacking Castanea dentata and other plants typical of the Blue Ridge. Examples generally have a well-developed deciduous low heath shrub layer or poorly developed shrub and herb layers.
Distinguishing Features: The Piedmont Monadnock Subtype) is distinguished from all other subtypes by the absence of Castanea dentata, Rhododendron calendulaceum, Pyrularia pubera, Gaylussacia ursina, Magnolia fraseri, Carex pensylvanica, Maianthemum racemosum, and other plants typical of the Blue Ridge region. Typically Piedmont species such as Quercus falcata and Quercus stellata are often present.

CHESTNUT OAK FOREST (UWHARRIE DRY SUBTYPE?)

Synonyms: Quercus prinus-Quercus stellata-Carya glabra/Vaccinium arboreum-Amorpha schwerinii Forest (4416).
Defined from Uwharrie data. Relation to other communities unclear.

Piedmont Edaphic and Fire-maintained Woodlands


XERIC HARDPAN FOREST (BASIC HARDPAN SUBTYPE)

Synonyms: Quercus stellata-Carya (carolinae-septentrionalis, glabra)-(Quercus marilandica)/Ulmus alata/(Schizachyrium scoparium-Piptochaetium avenaceum) Woodland

(3714).
Concept: Type covers Piedmont forests and woodlands dominated by Quercus stellata, with or without Quercus marilandica, Carya carolinae-septentrionalis, or pines, occurring in environments that are xeric because of restricted rooting depth caused by dense clay, sometimes in combination with rock. Their flora indicates a drier environment than that of Dry Oak–Hickory Forest and the trees are often somewhat stunted Canopy density is less than in dry forests, and depends more on fire and disturbance history. Subtype covers examples on broad upland flats developed over mafic rocks, where a clay hardpan sometimes creates wet as well as dry conditions and where acid-loving flora is absent or scarce and some basic indicators are present.
Distinguishing Features: Xeric Hardpan Forests are distinguished from Dry Oak–Hickory Forest and Dry Basic Oak–Hickory Forest by having a canopy of more xerophytic composition, with Quercus stellata or Quercus marilandica predominant and with Quercus alba and more mesic oaks uncommon. Fire-suppressed degraded examples of Piedmont Longleaf Pine Forest may be dominated by Quercus stellata and other xerophytic species, but will not occur on flat hardpan soils or rocky mafic ridges, will generally have evidence of the past presence of Pinus palustris and its associates, and will have a flora with more Coastal Plain affinities. Xeric Hardpan Forests are distinguished from Montane Red Cedar–Hardwood Woodland and other rock outcrop-related

woodlands by clayey soils and absence of characteristic rock outcrop flora.


The Basic Hardpan Subtype is distinguished from the Prairie Barren Subtype by the absence of a substantial component of the characteristic flora of prairie affinities, excluding widespread prairie species such as Schizachyrium scoparium. (see the Prairie Barren Subtype for this flora). It is distinguished from the Basic Rocky Subtype by occurrence on broad upland flats, generally with no rock outcrops, rather than on bouldery ridge tops or steep slopes. Quercus phellos or other species typical of wetter conditions are generally present in small numbers. No plants are known to be exclusively in the Basic Rocky Subtype and very constant, but Carya carolinae-septentrionalis, Piptochaetium avenaceum, Acer leucoderme, Vitis rotundifolia, and Parthenocissus quinquefolius are generally much more abundant than in the Basic Hardpan Subtype. The Basic Hardpan Subtype is distinguished from the Acidic Hardpan Subtype by a flora indicative of mafic substrate influence in the soil. Acid-loving flora such as Chimaphila maculata, Vaccinium species (other than V. arboreum and some V. stamineum), Gaylussacia spp., and Oxydendrum arboreum are absent or scarce. More base-loving flora such as Clematis ochroleuca, Viburnum spp., Symphoricarpos orbiculatus, Rhus aromatica, Cercis canadensis, Fraxinus americana, and Ulmus alata are usually common.
Comments: This subtype also occurs in Virginia, but the hardpan effect seems to be less extreme and the community is less distinct. Quercus alba is a more major component.

XERIC HARDPAN FOREST (PRAIRIE BARREN SUBTYPE)

Synonyms: Quercus stellata-(Pinus echinata)/Schizachyrium scoparium-Echinacea laevigata-Solidago ptermicoides Woodland (3558). Diabase Barren.
Concept: Subtype covers examples on mafic rock-derived montmorillonitic soils which contain a substantial component of herbs of prairie affinities and generally a higher species richness than the Basic Hardpan Subtype. The cause of differences between this subtype and the Basic Hardpan Subtype is not known. It may represent simply a more continuous fire history, with the Basic Hardpan Subtype being depauperate and somewhat degraded examples of the same original type; however, the range of remaining examples and of characteristic plants suggests it may represent a biogeographic difference or a more extreme edaphic situation.
Distinguishing Features: The Prairie Barren Subtype is distinguished from the closely related Basic Hardpan Subtype and from all other subtypes by the presence of a substantial flora of prairie affinities, beyond widespread species such as Schizachyrium scoparium. Silphium terebinthinaceum, Echinacea laevigata, Cirsium carolinianum, Elymus canadensis, Eryngium yuccifolium, Liatris aquarrosa, Parthenium auriculatum, Parthenium integrifolium, Tragia urens, and Sorghastrum nutans are typical of the Prairie Barren Subtype and not the other subtypes.
Comments: The few examples are in the area near Butner, around the Durham-Granville County line. This area has a large expanse of diabase, and the characteristic rich flora may represent a center of diversity associated with a large amount of habitat, with the more widespread Basic Hardpan Subtype representing naturally more depauperate communities away from this center. A different flora of prairie affinities is present on roadsides in the large area of gabbro in and around Mecklenburg County, including Helianthus schweinitzii, Aster georgianus, and Gnaphalium helleri. It may represent a different kind of prairie barren, developed in a different concentration of habitat. Quercus marilandica-Quercus stellata/Schizachyrium scoparium-Silphium terebinthinaceum Woodland (3711), known from nearby South Carolina, may represent a natural example of the community represented by the roadside prairie flora in this part of North Carolina.

XERIC HARDPAN FOREST (ACIDIC HARDPAN SUBTYPE)

Synonyms: Quercus stellata-(Quercus marilandica)/Gaylussacia frondosa Hardpan Woodland (4413).
Concept: Subtype covers Xeric Hardpan Forests on acidic clays, having an acid-loving flora.
Distinguishing Features: The Acidic Hardpan Subtype can be distinguished from all other subtypes by the substantial presence of acid-loving flora, such as Vaccinium tenellum, Vaccinium pallidum, Gaylussacia spp., Oxydendrum arboreum, and Chimaphila maculata. The strongest basic indicators, such as Symphoricarpos orbiculatus, Rhus aromatica, Clematis ochroleuca, and the prairie species are absent, and weaker indicators such as Cercis canadensis and Ulmus alata are much less common. Quercus falcata may be abundant.
Comments: Less extremely developed parts of this community in the Gold Hill area of Rowan County have substantial Quercus falcata in the canopy.

XERIC HARDPAN FOREST (BASIC ROCKY SUBTYPE)

Synonyms: Quercus stellata-Carya carolinae-septentrionalis/Piptochaetium avenaceum-Danthonia spicata Woodland (3713).
Concept: Subtype covers the rare communities with Xeric Hardpan Forest composition on rocky ridge tops and steep slopes on mafic rocks. Soils between the rocks appear to be montmorillonitic and to restrict water movement and presumably root penetration. The composition is slightly different from examples on basic hardpan flats.
Distinguishing Features: The Basic Rocky Subtype is distinguished from the other basic subtypes by its occurrence on steep slopes or ridge tops and the presence of abundant rocks. The species indicative of wetter conditions, such as Quercus phellos, which are usually present in small numbers in the hardpan subtypes, are absent. No plants are known to be exclusively in the Basic Rocky Subtype and very constant, but Carya carolinae-septentrionalis, Piptochaetium avenaceum, Acer leucoderme, Vitis rotundifolia, and Parthenocissus quinquefolius are generally much more abundant than in the Basic Hardpan Subtype. This subtype may grade conceptually into some of the rock outcrop woodlands. It is distinguished from them by its clayey soils and absence of characteristic rock outcrop flora.

XERIC PIEDMONT PINE HEATH

Synonyms: Pinus echinata-Quercus marilandica/Kalmia latifolia-Symplocos tinctoria Woodland (4446).
Concept: Xeric rocky slopes with open canopy of Pinus echinata and dry hardwoods and a dense shrub layer of Kalmia latifolia and other acid-loving shrubs. This association is known from only a single site in the Uwharrie Mountains.
Distinguishing Features: The combination of open xerophytic pine or pine-hardwood canopy and dense tall heath shrub layer in a rugged and rocky site distinguishes this type from all others. Piedmont Longleaf Pine Forest (Rocky Subtype) is the most closely related community, occurring in a similar setting.

SOUTHERN MOUNTAIN XERIC PINE-OAK WOODLAND

Synonyms: Pinus echinata-Quercus stellata-Quercus marilandica/Vaccinium pallidum Woodland (3765).

Concept: Type is an open woodland on xeric slopes of the lower Blue Ridge escarpment, dominated by a mix of Pinus echinata, Quercus stellata, and Quercus marilandica, with acid-loving heath shrub layer containing some typically montane species such as Kalmia latifolia and Gaylussacia baccata. It was described in South Carolina and Georgia; no examples are known in North Carolina and it is unclear if it occurs here.

DRY PIEDMONT LONGLEAF PINE FOREST (TYPIC SUBTYPE)

Synonyms: Pinus palustris-Pinus echinata-(Pinus virginiana)/Quercus marilandica-(Quercus prinus)/Vaccinium pallidum Woodland (8437). Piedmont Longleaf Pine Forest (Dry Variant)


Concept: Type covers woodlands or forests of the eastern Piedmont (primarily the Uwharries and areas adjacent to the Sandhills) in which Pinus palustris naturally dominates or codominates. Pinus palustris may be scarce in examples where past logging and fire suppression have removed it and allowed other pines and hardwoods in. Subtype covers most of the North Carolina examples, occurring on gently rolling uplands and slopes, usually on silty or clayey soils.
Distinguishing Features: Dry Piedmont Longleaf Pine Forest is distinguished from all other Piedmont dry communities by having a component of Pinus palustris or evidence that it once dominated. In degraded examples the canopy may resemble Dry Oak–Hickory Forest, or may be dominated by Pinus taeda and Pinus echinata, with only scattered Pinus palustris. It is distinguished from Wet Piedmont Longleaf Pine Forest by its overall dry to dry-mesic flora, lacking any appreciable amount of wetland species or even mesic species such as Panicum virgatum or Chasmanthium laxum. It is distinguished from most longleaf pine communities of the adjacent Coastal Plain by lacking Aristida stricta, Quercus laevis, Quercus incana, and Quercus margarettiae, as well as its Piedmont location. The Northern Subtype of Pine/Scrub Oak Sandhill also lacks Aristida stricta, but contains the Coastal Plain scrub oaks.

The Typic Subtype is distinguished from the rarer Rocky Subtype by occurring on more gently sloped and drier sites, and having a more mixed hardwood and shrub component rather than one dominated by Quercus marilandica and Quercus montana. This may reflect more frequent fire in this subtype.


Comments: This type covers a broader range of moisture and topographic positions than Piedmont hardwood forests. It may be that additional subtypes should be recognized, but their distinction is hidden by the universal alteration by past fire suppression in all remaining examples.

DRY PIEDMONT LONGLEAF PINE FOREST (ROCKY SUBTYPE)

Synonyms: Pinus palustris-Quercus marilandica-Quercus montana/Symplocos tinctoria Woodland (4554).
Concept: Subtype covers the extremely rare examples on steep, rocky slopes, where fire is likely less frequent and Pinus palustris’s presence is apparently maintained partly by the dry site conditions.
Distinguishing Features: The Rocky Subtype is distinguished by occurring on steep, rocky sites in rugged terrain. The floristic differences believed to exist between the two subtypes are blurred by the effects of past cutting and fire suppression in all examples.


ULTRAMAFIC OUTCROP BARREN

See Mountain Guide. The single Piedmont example is currently placed in the class as the mountain examples, though it is quite different and may warrant a separate subtype.

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