KUCHLER TYPE DESCRIPTION
Kuchler Type: Pocosin


PHYSIOGRAPHY : 
Pocosins occur on low flatlands along or near the coast and are
characterized by broad, shallow stream basins [14].


CLIMATE : 
Average rainfall for the coastal region is 48.5 inches (1,230 mm)
annually.  July and August are typically the wettest months.
Evaporation usually exceeds rainfall in June and about equals rainfall
in July and August [13].


SOILS : 
Pocosins occur on highly organic or peaty soils with prolonged
inundation and poor drainage.  Peat depths can range from 24 inches to
more than 60 inches (60 to>150 cm). As many as 40 different soils are
found under the pocosin community.  The organic mucks and peats
characteristic of pocosins contain or are underlain by layered marine
sediments varying in texture from clay to sand.  The organic horizon has
a pH of 3.5 to 4.1, while mineral soils are only slightly less acidic.
The soil's organic layer can be as deep as 16 inches (40 cm) [14].
Pocosin soils are nutrient deficient, especially in phosphorus [19].
Physical and chemical soil properties for pocosins have been listed
[13].


VEGETATION : 
Typically pocosins are shrub bogs with only scattered stems of pond pine
(Pinus serotina) and occasionally loblolly pine (P. taeda) or longleaf
pine (P. palustris) [14].  Pond pine and inkberry (Ilex glabra) are
listed as dominant overstory species [8].  Shrub cover is usually 1.5 to
13 feet (0.5-4 m) high.  "Short pocosins" are classified as those with
trees less than 20 feet (6 m) high.  "Tall pocosins" are characterized
by trees over 20 feet (6 m) high.  Species that are common on
better-drained sites include loblolly and longleaf pines, sweet
pepperbush (Clethra alnifolia), fetterbush (Lyonia lucida), zenobia
(Zenobia pulverulenta), and blueberry (Vaccinium spp.).  Species found
on less peaty sites include sweetbay (Magnolia virginiana),
loblolly-bay (Gordonia lasianthus), and red maple (Acer rubrum) [14].
Other species of pocosins include titi (Cyrilla racemiflora), wax myrtle
(Myrica cerifera), redbay (Persea borbonia), greenbrier (Smilax
laurifolia), moss (Sphagnum spp.), baldcypress (Taxodium spp.), tupelo
(Nyssa spp.), and Atlantic white-cedar [8,14].

Endangered plants include white wicky (Kalmia cuneata), arrowleaf
shieldwort (Paltandra sagittae-folia), spring flowering goldenrod
(Solidago verna), rough-leaf loosestrife (Lysimachia asperulaefolia),
and white beadrush (Rynchospora alba).  Threatened plants include Venus
flytrap (Dionaea muscipula), dwarf fothergilla (Fothergilla gardenii),
and sweet pitcher-plant (Sarracenia rubra) [13].


WILDLIFE : 
Research concerning pocosin fauna and the importance of pocosin habitat
has been very limited, but many species have been recorded [13].  These
include many reptiles and amphibians, rodents, black bear, bobcat, fox,
bats, white-tailed deer, opossum, raccoon, river otter, mink, muskrat,
northern bobwhite, American woodcock, and several species of fish
[4,13,14].


ECOLOGICAL RELATIONSHIPS : 
Pocosins are highly efficient at storing and regulating fresh water,
which may contribute to regional ecosystem stability [13].  The
thickness of the peat layer, hydroperiod length, and frequency and
severity of fire all control the distribution and composition of pocosin
vegetation.  Typically pocosins occur where the water table is at or
near the surface for 6 to 12 months per year [14]. High
evapotranspiration rates in summer can lower the water table to 24 to
35.5 inches (60-90 cm) below the surface.  Short pocosins occur on deep
peats (>3 feet [1 m]) that are nutrient deficient. Tall pocosins usually
occur on shallow peats (20-40 inches [50-100 cm]) with a higher nutrient
content and have greater biomass production.  With a decrease in peat
depth and inundation pocosins become pine flatwoods [13].

Two pocosin communities have been identified in the Green Swamp, North
Carolina.  The suitability of the classification has not been determined
outside of the Green Swamp, but this remains one of the most
comprehensive classifications to date.  The first class is pine and
heath shrub (pond pine/titi-zenobia), which develops on deep to
intermediate organic soils with long hydroperiods and frequent fire.
The second class is conifer-hardwood (pond pine-red maple-swamp tupelo
[Nyssa sylvatica]/titi-fetterbush), which develops on shallow organic
soils with shorter hydroperiods. No fire frequencies for this class are
discribed [14].

There is a tendency for titi to dominate pocosin sites in northeastern and
central North Carolina and fetterbush to dominate sites further south.
Zenobia dominates sites in both these areas following fire, especially
where productivity is low and species diversity is high [14].

Pocosins have complex successional trends owing to the interactions of
nutrient availability, hydroperiod, and fire.  It is possible that
pocosins were initially marsh vegetation dominated by grasses and
aquatic macrophytes, and succeeded to Atlantic white-cedar and
baldcypress.  Pocosins expanded with peat accumulation and the rise of
the water table.  Fires set by Native Americans and then white settlers
may have expanded pocosins [14].  A discussion of successional trends
related to fire, as summarized in the literature, follows.

Titi, inkberry, and fetterbush often dominate unburned pocosins [2].
Without fire Atlantic white-cedar communities succeed to titi, redbay,
and sweetbay [12].  Pocosins may eventually succeed to swamp forest
dominated by swamp tupelo, sweetgum (Liquidambar styraciflua) and red
maple if the process is not impeded by deep peat [14].

Low-intensity fires usually change pocosin species composition very
little [13].  Inkberry-titi-zenobia communities are maintained by
frequent fire [12].  Frequent fire can also maintain pond pine stands,
but frequent fire during the dry season may completely eliminate pond
pine and establish a grass-sedge bog or savannah [1].

Severe fires may reduce peat depth, converting short pocosins to marshes
[13].  In Atlantic white-cedar, sweetbay, redbay, or baldcypress-tupelo
communities, severe fires are usually followed by stands of inkberry,
titi, and zenobia [12].  Pond pine usually succeeds Atlantic white-cedar
following fire if a seed source is present, although cedar may
eventually establish also [1].  Blueberry, zenobia, and wicky (Kalmia
carolina) occassionally dominate severely burned sites.  Herbs that can
appear following fire include chain fern (Woodwardia virginica),
Osmunda spp., bracken fern (Pteridium aquilinum), sedge (Carex
walteriana), Lachnanthes caroliniana, meadow beauties (Rhexia spp.), and
pitcher-plant (Sarracenia spp.) [2].

For more information on community dynamics in pocosin types refer to
Christensen [21].  For detailed information on pocosin dynamics refer to
Richardson and Gibbons [22].

Related categories for Kuchler Type: Pocosin