Fourth approximation guide


Wet nonalluvial forests of the Coastal Plain



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Wet nonalluvial forests of the Coastal Plain

WET MARL FOREST G1

TNC Name: Carya cordiformis-Quercus pagoda-Quercus shumardii-Carya myristiciformis/Sabal minor-Cornus asperifolia Forest (7316).


Concept: Perched wetland forest of nonalluvial flats shallowly underlain by limestone, dominated by calciphilic and rich-site wetland hardwood forest species, particularly Carya myristiciformis.
Distinguishing Features: Wet Marl Forests may be distinguished from Nonriverine Wet Hardwood Forests by the marl-derived, calcareous soils and the strong presence of calciphilic plant species such as Carya myristiciformis, Tilia caroliniana, and Cornus asperifolia, along with an abundance of other species of rich sites such as Carya cordiformis, Quercus shumardii, Acer floridanum, Acer negundo, Cercis canadensis, and Sabal minor. Wet Marl Forests are distinguished from Coastal Plain Marl Outcrop and Basic Mesic Forest by their occurrence on poorly drained flats and by the abundance of wetland species.

NONRIVERINE WET HARDWOOD FOREST (OAK FLAT SUBTYPE) G2

TNC Name: Quercus michauxii-Quercus pagoda/Clethra alnifolia-Leucothoe axillaris Forest (7449).


Concept: Type covers wetland forests of nonalluvial flats not underlain by limestone, dominated by wetland oaks and other hardwoods. Subtype covers the more mesic (though still wet) examples, dominated by combinations of Quercus michauxii, Quercus pagoda, and Liquidambar styraciflua.
Distinguishing Features: The Nonriverine Wet Hardwood Forest type is distinguished by the dominance of bottomland oaks and Liquidambar in a site not subject to overland flooding. The dominance of the shrub layer by Leucothoe axillaris or Clethra alnifolia distinguishes them from Brownwater Bottomland Hardwoods and most Blackwater Bottomland Hardwoods. The canopy composition also distinguishes them from Blackwater Bottomland Hardwoods. Nonriverine Wet Hardwood Forests are distinguished from Nonriverine Swamp Forests, which may occur in similar settings and are sometimes associated, by the canopy dominance of oaks or Liquidambar rather than Nyssa or Taxodium. Disturbed examples of either may become strongly dominated by Pinus taeda, and may be distinguishable only by undergrowth.

The Oak Flat Subtype is distinguished by a canopy consisting of Quercus michauxii, Quercus pagoda, or a mixture of oaks rather than dominated by Quercus laurifolia and Nyssa biflora.


Comments: These community often become strongly dominated by Pinus taeda or Liquidambar styraciflua is clearcut. It is possible that some naturally Liquidambar-dominated examples occur.
NONRIVERINE WET HARDWOOD FOREST (OAK-GUM SLOUGH SUBTYPE) G2G3

TNC Name: Quercus laurifolia-Nyssa biflora/Clethra alnifolia-Leucothoe axillaris Forest (7447).


Concept: Type covers wetland forests of nonalluvial flats not underlain by limestone, dominated by wetland oaks and other hardwoods. Subtype covers the wetter examples, dominated by Quercus laurifolia, often with abundant Nyssa biflora. These examples are transitional to Nonriverine Swamp Forest.
Distinguishing Features: The Nonriverine Wet Hardwood Forest type is distinguished by the dominance of bottomland oaks and Liquidambar in a site not subject to overland flooding. The dominance of the shrub layer by Leucothoe axillaris or Clethra alnifolia distinguishes them from Brownwater Bottomland Hardwoods and most Blackwater Bottomland Hardwoods. The canopy composition also distinguishes them from Blackwater Bottomland Hardwoods. Nonriverine Wet Hardwood Forests are distinguished from Nonriverine Swamp Forests, which may occur in similar settings and are sometimes associated, by the canopy dominance of oaks or Liquidambar rather than Nyssa or Taxodium. Disturbed examples of either may become strongly dominated by Pinus taeda, and may be distinguishable only by undergrowth.

The Oak--Gum Slough Subtype is distinguished by the dominance of Quercus laurifolia and Nyssa biflora, usually with only minor amounts of Quercus michauxii or Quercus pagoda.


Comments: There are fewer records for this subtype than for the Oak Flat Subtype. It may, however, be overlooked. It is generally associated with the Oak Flat Subtype and is less extensive.

NONRIVERINE SWAMP FOREST (CYPRESS--GUM SUBTYPE) G2G3

TNC Name: Taxodium distichum-Nyssa biflora/Berchemia scandens-Toxicodendron radicana/Woodwardia areolata Forest (4429). Nyssa biflora-Acer rubrum var. trilobum/Persea palustris Forest (7445) (successional version of all Nonriverine Swamp Forests)


Concept: Type covers the wettest, saturated to shallowly flooded, nonriverine wetlands, with canopies dominated by combinations of Nyssa biflora, Taxodium distichum, and Acer rubrum. Subtype covers the wettest examples, with canopies of Taxodium distichum and Nyssa biflora, and Nyssa aquatica and Fraxinus sp. often present. Ground water input as well as poor drainage may be responsible for the wetness of this subtype, and minerals in ground water may give it some of its distinctive character. This subtype is most like riverine swamps in flora and vegetation structure.
Distinguishing Features: Nonriverine Swamp Forests are distinguished from Cypress--Gum Swamps and Tidal Cypress--Gum Swamps by occurring on wet flats or basins away from the influence of rivers.

The Cypress--Gum Subtype is distinguished by strong dominance by Taxodium distichum and Nyssa spp. In known examples this is associated with composition more similar to river swamps and a smaller component of pocosin shrubs than in other subtypes.


Comments: This subtype is the rarest.


NONRIVERINE SWAMP FOREST (MIXED SUBTYPE) G2G3

TNC Name: Pinus taeda-Chamaecyparis thyoides-Acer rubrum-Nyssa biflora/Lyonia lucida-Clethra alnifolia Forest (7558). Nyssa biflora-Acer rubrum var. trilobum/Persea palustris Forest (7445) (successional version of all Nonriverine Swamp Forests)


Concept: Type covers the wettest, saturated to shallowly flooded, nonriverine wetlands, with canopies dominated by combinations of Nyssa biflora, Taxodium distichum, and Acer rubrum. Subtype covers examples with moderate to deep organic soil, dominated by a mixture of hardwoods and conifers that includes Pinus taeda, Chamaecyparis thyoides, or Pinus serotina, as well as the typical dominants. At least some of these examples are subject to occasional wind tidal flooding, which may be important in determining their distinctive character.
Distinguishing Features: Nonriverine Swamp Forests are distinguished from Cypress--Gum Swamps and Tidal Cypress--Gum Swamps by occurring on wet flats or basins away from the influence of rivers. The distinction with Tidal Cypress--Gum Swamp is often subtle, and one type grades into the other along the large drowned rivers in the northeastern part of the state. In general, Tidal Cypress--Gum Swamp is distinguished by a significant component of Myrica cerifera, Rosa palustris, Osmunda regalis, Thelypteris palustris, and a variety of marsh herbs. In Nonriverine Swamp Forest these plants are replaced by those of pocosin affinities, such as Ilex glabra, Lyonia lucida, Persea palustris, Magnolia virginiana, Woodwardia virginica, and Sphagnum. Pines are often more abundant in Nonriverine Swamp Forests.

The Mixed Subtype is distinguished from other subtypes by having Pinus taeda or Chamaecyparis thyoides as substantial components, in addition to Nyssa, Taxodium, and Acer. This subtype often resembles Pond Pine Woodland and Peatland Atlantic White Cedar Forest in the lower strata, but differs in the canopy. Peatland Atlantic White Cedar Forests that have been logged and have not regenerated well are indistinguishable from poor quality examples of this subtype.


Comments: Heavily logged examples may return as the successional Nyssa biflora-Acer rubrum var. trilobum/Persea palustris or as a secondary bay forest (Persea palustris-Magnolia virginiana).

NONRIVERINE SWAMP FOREST (POPLAR-PAWPAW SUBTYPE) G2

TNC Name: Nyssa biflora-Acer rubrum-Liriodendron tulipifera/Magnolia virginiana-Asimina triloba/Clethra alnifolia Forest (4428). Nyssa biflora-Acer rubrum var. trilobum/Persea palustris Forest (7445) (successional version of all Nonriverine Swamp Forests)

Concept: Type covers the wettest, saturated to shallowly flooded, nonriverine wetlands, with canopies dominated by combinations of Nyssa biflora, Taxodium distichum, and Acer rubrum. Subtype covers examples on shallow organic or mucky mineral soil, with slightly richer vegetation that contains substantial amounts of Liriodendron tulipifera in the canopy and/or Asimina triloba in the understory. These species are generally not dominant, but are abundant and indicate a somewhat richer and less wet site.
Distinguishing Features: Nonriverine Swamp Forests are distinguished from Cypress--Gum Swamps and Tidal Cypress--Gum Swamps by occurring on wet flats or basins away from the influence of rivers.

The Poplar-Pawpaw Subtype is distinguished from all other subtypes by having Liriodendron tulipifera and Asimina triloba as significant components of the canopy and the shrub layer respectively.


Comments: The naturallness of this subtype is somewhat controversial. The mixture of drier site species with wetter site species suggests possible changing hydroperiod. Other aspects of the examples suggest they are naturally distinct from other subtypes, though the canopy composition probably naturally contained more conifers than any examples now existing. As all examples have been ditched for a long time (as most other subtypes have also been), it is difficult to tell.

NONRIVERINE SWAMP FOREST (SWEETGUM SUBTYPE) G2?

TNC Name: Nyssa biflora-Liquidambar styraciflua-Acer rubrum/Clethra alnifolia Forest (4679).


Concept: Type covers the wettest, saturated to shallowly flooded, nonriverine wetlands, with canopies dominated by combinations of Nyssa biflora, Taxodium distichum, and Acer rubrum. Subtype covers examples with mineral soil, containing substantial amounts of Liquidambar styraciflua in the canopy.
Distinguishing Features: Nonriverine Swamp Forests are distinguished from Cypress--Gum Swamps and Tidal Cypress--Gum Swamps by occurring on wet flats or basins away from the influence of rivers.

The Sweetgum Subtype is distinguished from other subtypes by the presence of Liquidamber styraciflua in either the canopy or understory, reflecting a more mineral soil, with only shallow or no organic matter.


Comments: This subtype is less wet than other subtypes. It may not be distinct from the Sweetgum Variant of Nonriverine Wet Hardwood Forest. The Liquidambar is probably increased in all examples as a result of past logging, but serves as an indicator of mineral soil.


NONRIVERINE SWAMP FOREST (DEPRESSION SUBTYPE)

TNC Name: Nyssa biflora / Itea virginica _ Cephalanthus occidentalis Depression Forest (7434).


Nyssa biflora-Taxodium ascendens/Cyrilla racemiflora-(Ilex amelanchier) Forest. Suggested name not in NVC.
Concept: Type covers the wettest, saturated to shallowly flooded, nonriverine wetlands, with canopies dominated by combinations of Nyssa biflora, Taxodium distichum, and Acer rubrum. Subtype covers examples in closed basins where surface water is deeper, strongly dominated by flood-tolerant trees such as Nyssa biflora and Taxodium ascendens.
Distinguishing Features: Nonriverine Swamp Forests are distinguished from Cypress--Gum Swamps and Tidal Cypress--Gum Swamps by occurring on wet flats or basins away from the influence of rivers.

The Depression Subtype is distinguished from all other subtypes by occurring in pronounced basins, usually Carolina bays. This is generally accompanied by having Taxodium ascendens dominant or codominant, rather than Taxodium distichum. Cyrilla racemiflora or Ilex amelanchier usually dominate the shrub layer.

Comments: This subtype is more distantly related than the other subtypes ecologically. Its basin hydrology and longer hydroperiod may warrant treating it as a different community type, related to other basin wetlands.

Pocosin and pealand communities of the Coastal Plain

LOW POCOSIN (GALLBERRY-FETTERBUSH SUBTYPE) G2

TNC Name: Ilex glabra-Lyonia lucida-Zenobia pulverulenta Shrubland (3944).


Concept: Type covers pocosin shrublands with prevailing natural shrub height less than 1.5 meters tall due to deep peat edaphic conditions or wetness. Subtype covers more northern and inland examples in which Cyrilla racemiflora is absent or only a minor component.
Distinguishing Features: Low Pocosins are distinguished from other pocosin communities by the persistent low stature of the shrubs (less the 1.5 meters tall). Most Low Pocosins do contain patches of taller shrubs and scattered, stunted Pinus serotina, but these are a minor component. The transition to High Pocosin sometimes occurs as an increase in abundance of tall shrub patches rather than a gradual increase in shrub height. In general Low Pocosins can be distinguished from even recently burned High Pocosins by the smaller stature of the pines. Low Pocosins are distinguished from Pocosin Openings by strong dominance of erect shrubs, with only a minor component of Chamaedaphne calyculata and of herbs.

The Gallberry-Fetterbush Subtype is distinguished from the Titi Subtype by the absence of Cyrilla racemiflora and corresponding geographic location. Cyrilla racemiflora may be present in nearby Pond Pine Woodland communities or even in scattered tall shrub patches, but is scarce or absent within the Low Pocosin itself.

Comments: Low Pocosins often contain small openings dominated by herbs and Chamaedaphne calyculata. In the Third Approximation these were treated as part of the Low Pocosin. In the Fourth Approximation they are treated as a separate community, albeit one that is often intermixed in small patches.

LOW POCOSIN (TITI SUBTYPE) G2G3

TNC Name: Cyrilla racemiflora-Zenobia pulverulenta Shrubland (3943).


Concept: Type covers pocosin shrublands with prevailing natural shrub height less than 1.5 meters tall due to deep peat edaphic conditions or wetness. Subtype covers more southern examples in which Cyrilla racemiflora is a major component.
Distinguishing Features: Low Pocosins are distinguished from other pocosin communities by the persistent low stature of the shrubs (less the 1.5 meters tall). Most Low Pocosins do contain patches of taller shrubs and scattered, stunted Pinus serotina, but these are a minor component. The transition to High Pocosin sometimes occurs as an increase in abundance of tall shrub patches rather than a gradual increase in shrub height. In general Low Pocosins can be distinguished from even recently burned High Pocosins by the smaller stature of the pines. Low Pocosins are distinguished from Pocosin Opening communities by strong dominance of erect shrubs, with only a minor component of Chamaedaphne calyculata and of herbs.

The Gallberry-Fetterbush Subtype is distinguished from the Titi Subtype by the absence of Cyrilla racemiflora and corresponding geographic location.



POCOSIN OPENING (SEDGE-FERN SUBTYPE) G1G2

TNC Name: Chamaedaphne calyculata/Carex striata var. striata-Woodwardia virginica Dwarf-Shrubland (4163).


Concept: Type covers patches of herbaceous or dwarf shrub dominance within Low or High Pocosin. Individual patches are usually small but sometimes abundantly intermixed with Low Pocosin shrub vegetation. Subtype covers the common openings, dominated by the species listed but lacking abundant Vaccinium macrocarpon or Sarracenia spp.
Distinguishing Features: Pocosin Openings are distinguished from Low Pocosins by the predominance of Chamaedaphne calyculata, Woodwardia virginica, Carex striata, and Sphagnum over Zenobia and other taller shrubs.

The Sedge-Fern Subtype is distinguished by a lack of significant amounts of Vaccinium macrocarpon or Sarracenia spp.


Comments: These communities usually occur in small patches closely mixed with the shrubby Low Pocosin vegetation. They were included within the range of Low Pocosin in the Third Approximation, but are treated as a separate kind of community here. Pocosin Openings are believed to be created by hot fire. Over time they succeed to shrubby vegetation, but they may persist for some decades

POCOSIN OPENING (PITCHER PLANT SUBTYPE) G1

TNC Name: Chamaedaphne calyculata/Carex striata-Sarracenia (flava, purpures, rubra spp. rubra) Dwarf-Shrubland (4164).


Concept: Type covers patches of herbaceous or dwarf shrub dominance within Low or High Pocosin. Individual patches are usually small but sometimes abundantly intermixed with Low Pocosin shrub vegetation. Subtype covers the rare examples which have some combination of Sarracenia spp. as a dominant or codominant.
Distinguishing Features: Pocosin Openings are distinguished from Low Pocosins by the predominance of Chamaedaphne calyculata, Woodwardia virginica, Carex striata, and Sphagnum over Zenobia and other taller shrubs.

The Pitcher Plant Subtype is distinguished by having greater than 25% cover by Sarracenia spp.



POCOSIN OPENING (CRANBERRY SUBTYPE) G1

TNC Name: Chamaedaphne calyculata-Vaccinium macrocarpon/Carex striata var. striata-Woodwardia virginica Dwarf-Shrubland (4165).


Concept: Type covers patches of herbaceous or dwarf shrub dominance within Low or High Pocosin. Individual patches are usually small but sometimes abundantly intermixed with Low Pocosin shrub vegetation. Subtype covers the rare examples which have Vaccinium macrocarpon as a significant component.
Distinguishing Features: Pocosin Openings are distinguished from Low Pocosins by the predominance of Chamaedaphne calyculata, Woodwardia virginica, Carex striata, and Sphagnum over Zenobia and other taller shrubs.

The Cranberry Subtype is distinguished by having greater than 25% cover by Vaccinium macrocarpon.



HIGH POCOSIN (EVERGREEN SUBTYPE) G3

TNC Name: Pinus serotina/Lyonia lucida-Ilex glabra-(Cyrilla racemiflora) Shrubland (3846).


Concept: Type covers pocosin communities of persistent intermediate shrub stature and lacking well-developed tree canopy. Subtype covers the common examples dominated strong by evergreen shrubs.

Distinguishing Features: High Pocosins are distinguished from other peatland pocosins by having dense shrub layers persistently greater than 1.5 meters tall (except immediately after fire) but lacking a well-developed tree canopy (cover less than 25%). They are distinguished from Streamhead Pocosins by not occurring in seepage-fed drainages in sandhill terrain. They lack Liriondendron tulipifera, Toxicodendron vernix, and other characteristic streamhead species and may have Gordonia lasianthus as a component. They are distinguished from the Pocosin Shrub Subtype of Natural Lake Shoreline by lacking hydrology affect by a lake.

The Evergreen Subtype is distinguished from the Deciduous Subtype by having only a minor amount of deciduous shrubs such as Zenobia pulverulenta and Vaccinium spp.
Comments: Occurs in southern Virginia on small peat bodies along tidal rivers. Not known to occur in NC in such sites.

HIGH POCOSIN (DECIDUOUS SUBTYPE) G2?

TNC Name: Pinus serotina/Zenobia pulverulenta-Cyrilla racemiflora-Lyonia lucida Woodland Shrubland (4458).


Concept: Type covers pocosin communities of persistent intermediate shrub stature and lacking well-developed tree canopy. Subtype covers the uncommon examples with a significant deciduous shrub component.
Distinguishing Features: High Pocosins are distinguished from other peatland pocosins by having dense shrub layers persistently greater than 1.5 meters tall (except immediately after fire) but lacking a well-developed tree canopy (cover less than 25%). They are distinguished from Streamhead Pocosins by not occurring in seepage-fed drainages in sandhill terrain. They lack Liriondendron tulipifera, Toxicodendron vernix, and other characteristic streamhead species and may have Gordonia lasianthus as a component. They are distinguished from the Pocosin Shrub Subtype of Natural Lake Shoreline by lacking hydrology affect by a lake.

The Deciduous Subtype is distinguished from the Evergreen Subtype by having more than a minor amount of deciduous shrubs such as Zenobia pulverulenta and Vaccinium spp.



POND PINE WOODLAND (SHRUB SUBTYPE) G3

TNC Name: Pinus serotina/Cyrilla racemiflora-Lyonia lucide-Ilex glabra Woodland (3670).


Concept: Type covers pocosin communities with a well-developed, though usually open, canopy of Pinus serotina, with or without Gordonia lasianthus. Subtype covers the common examples with canopies strongly dominated by Pinus serotina.
Distinguishing Features: The Pond Pine Woodland type is distinguished from High Pocosin by the presence of a significant tree canopy (greater than 25%). It is distinguished from Streamhead Pocosin by not occurring in seepage-fed drainages in sandhill terrain and in lacking Liriodendron tulipifera and other species typical of streamheads. It is most readily distinguished from Small Depression Pocosin by occurring in contiguous patches larger than 20 acres. It is distinguished from the Pond Pine Subtype of Estuarine Fringe Pine Forest by having a shrub layer dominated by typical pocosin shrubs rather than Myrica cerifera.

The Shrub Subtype is distinguished from the Loblolly Bay Subtype by not having Gordonia lasianthus as a canopy codominant. It is distinguished from the Canebreak Subtype/Phase by having broadleaf shrubs exceeding Arundinaria in cover.




POND PINE WOODLAND (LOBLOLLY BAY SUBTYPE) G3

TNC Name: Pinus serotina-Gordonia lasianthus/Lyonia lucida Woodland (3671).


Concept: Type covers pocosin communities with a well-developed, though usually open, canopy of Pinus serotina, with or without Gordonia lasianthus. Subtype covers examples with Gordonia lasianthus codominant in the canopy.
Distinguishing Features: The Pond Pine Woodland type is distinguished from High Pocosin by the presence of a significant tree canopy (greater than 25%). It is distinguished from Streamhead Pocosin by not occurring in seepage-fed drainages in sandhill terrain and in lacking Liriodendron tulipifera and other species typical of streamheads. It is most readily distinguished from Small Depression Pocosin by occurring in contiguous patches larger than 20 acres. It is distinguished from the Pond Pine Subtype of Estuarine Fringe Pine Forest by having a shrub layer dominated by typical pocosin shrubs rather than Myrica cerifera.

The Loblolly Bay Subtype is distinguished from the Shrub Subtype by having Gordonia lasianthus as a canopy codominant. It is distinguished from the Canebreak Subtype/Phase by having broadleaf shrubs exceeding Arundinaria in cover.


Comments: This subtype is distinguished only provisionally. It is not certain how ecologically significant Gordonia codominance in the canopy is, nor what it represents with regard to community development. It is often associated with the Shrub Subtype and does not have a distinct geographic range that can be determined from existing data.

POND PINE WOODLAND (NORTHERN SUBTYPE) G2?

TNC Name: Pinus serotina/Ilex glabra/Woodwardia virginica Woodland (4652).


Concept: Subtype covers examples at the northern end of the range, in which Cyrilla racemiflora is absent and Acer rubrum and Clethra alnifolia are important components.
Comments: Known only from the Great Dismal Swamp in North Carolina and Virginia and a few Virginia sites along the North Landing River.

POND PINE WOODLAND (CANEBRAKE SUBTYPE/PHASE) G1

TNC Name: Pinus serotina/Arundinaria gigantea ssp. tecta Woodland (4433). Pinus serotina/Arundinaria gigantea ssp. tecta Wooded Shrubland (3851).


Concept: Type covers pocosin-like communities dominated by Pinus serotina and pocosin shrubs or cane. Subtype covers examples with a shrub layer dominated by Arundinaria gigantea ssp. tecta, resulting from more frequent fire than that occurring in other Pond Pine Woodlands.
Distinguishing Features: Pond Pine Woodlands are distinguished from all other communities except Estuarine Fringe Pine Forest by having a well-developed (though usually open) canopy of Pinus serotina. They are distinguished from the Pond Pine Subtype of Estuarine Fringe Pine Forest by lacking appreciable Myrica cerifera in the shrub layer. Osmunda regalis is also generally scarce.

The Canebrake Subtype is distinguished from other subtypes by having a shrub layer with greater cover and Arundinaria than of broadleaf shrubs.


Comments: It is unclear whether to best regard this entity as a subtype or a phase of Pond Pine Woodland. Canebrakes succeed relatively quickly to broadleaf shrubs in the absence of fire. However, canebrakes were apparently abundant in early settlement times. The frequency of natural fires in some areas was probably great enough to allow some areas to persist as permanent canebrakes.


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