SE Coastal Plain and Piedmont

Southeastern Evergreen Forest

• Longleaf, Loblolly, and Slash Pine

• Maritime forest

• Cypress-gum

• Pocosin and Atlantic whitecedar

• Bottomland hardwood

• Hydrology, microtopography, soils, and disturbance are major factors that separate forest types from the Coastal Plain.

• Live oak (Quercus virginiana)

Maritime Forest

• Forest structure

• Species composition

  • Canopy

    • Live oak, loblolly pine, sand laurel oak

  • Shrubs

    • Yaupon holly, eastern redcedar, waxmyrtle

  • Understory/herb layer—sparse

• Wildlife value

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• Environmental factors

  • Disturbance

  • Temperature/precipitation not selective factors

  • Sandy soils

  • Wind and storms

  • Salt spray and overwash (forms thick canopy layer to protect from salt spray)

• Disturbance regime

• Threats

  • Development

  • Climate change, especially sea level rise (ghost forests)

• Which direction are we looking (north or south)?

  • 

    • North (ocean is East)

• What are the key environmental factors that shape maritime forests?

Cypress-Gum Forests

• Forest structure

  • often adjacent to bottomland sites

  • wettest of the coastal plain forest types; often flooded 3-6 months

  • Canopy of flood-tolerant species

  • Understory limited

  • No herbaceous layer

• Species composition

  • Brownwater swamps (more widespread)

    • Baldcypress and Nyssa biflora (smaller leaves than blackgum)

  • Blackwater swamps

    • Blackcypress and Nyssa aquatica

  • Other species: Carolina ash, red maple, black gum

• Environmental factors

  • Flooded in winter and early spring; flooded 3-6 months of the year

  • Flooding is the major selective factor that determines what species can survive

• Disturbance regime

  • No cycle of regular natural disturbance; no fire

  • Hurricanes are periodic

  • Can be very long-lived

• Threats

  • Climate change and saltwater intrusion

Carolina Bays, Pocosins, and Atlantic whitecedar

• IMPORTANT: While the origin of the word “pocosin” is Algonquin, it does NOT translate to “swamp on a hill.” It is a generic term that refers to a wet area

• Carolina bays describe some SE coastal plain geography; pocosins and Atlantic whitecedar are 2 community types found in Carolina Bays. Pocosins are closely related to Bay Forests.

Carolina Bays

• Elliptical bays that either have open water or wetland forests

• NW-SE orientation

• Mostly organic soils and “bay” forests (either pocosin or Atlantic whitecedar)

• Sandy rim (xeric longleaf pine forest) on the SE rims

• Many have been drained and converted to agriculture

• Ongoing debate about origin and formation

• Carolina bays were thought to have formed through wind and weather patterns

• Both types share seasonally wet, organic soils

• The main difference (we think) is the disturbance regime

  • Pocosin and Bay Forests—moderate fire regime (about 10 year cycle)

  • Atlantic whitecedar—infrequent but catastrophic fire

Pocosin or Bay Forest

• Environmental factors

  • Organic soils, from a few feet to 12 ft deep

  • Bays and depression ponds fill with partially decayed leaves, turns into “muck”

  • Organic soils hold water like a sponge

• Forest structure

  • Canopy often open—also described as an evergreen shrub bog

  • Drier sites have trees and are called Bay Forests

    • Thick and evergreen midstory or understory of “bay” species

    • Often woven together with vines

    • Little herbaceous understory

• Species composition

  • Canopy

    • Pond pine, Pinus serotina

  • Understory/shrub layer

    • Bay species: titi, sweetbay magnolia, swampbay, loblollybay

  • Vines weave everything together in a thick tangle

• Disturbance - 10 year fire cycle

  • Pond pine: fire adapted: serotinous cones, epicormic branching, thick bark to withstand some fire

• Threats

  • Former threats: ditching and draining for land conversion

  • Now: fire suppression, climate change

Atlantic Whitecedar Forests

• Forest structure and disturbance regime

  • used to exist in pure, even-ages stands

  • remaining stands like this are rare; some found in the Albemarle/Pamlico penninsula in NC

  • even-aged structure suggest that catastrophic disturbance is needed for regeneration

  • Fire cycle through to be > 50 years

  • Large plant biomass = hot fires, clears seed bed

  • Selective cutting converted forests to gum and red maple

• Species composition:

  • Atlantic whitecedar

Fire as a selective mechanism in the SE Coastal Plain

• Frequent, low-intensity

  • longleaf pine

  • plants are adapted to survive fire

    • seed germination during non-fire season (fall)

    • grass stage

    • long, lush protective needles

    • loss of dead branches

    • thick bark

• Infrequent, high-intensity

  • Atlantic whitecedar

  • plants can regenerate after fire

    • serotinous cones

    • abundant cone production; precocious (produce cones early)

    • short needles

    • dead branches retained (ladder)

    • thin bark

• Longleaf pine, pondpine, and whitecedar are all shade intolerant with different adaptations

Bottomland Hardwood Forests

• Forest structure

  • Geography: adjacent to brown or blackwater rivers, with periodic flooding

  • Closed canopy

  • Understory variable but uneven-aged, can be shrubby

  • Herb layer may or may not be rich

• Species composition

  • Brownwater rivers

    • higher diversity; nutrient-rich sediment

    • Oaks dominant

    • Also green ash, sweetgum, American elm, musclewood

  • Blackwater rivers

    • Quercus laurifolia and Pinus taeda dominant

    • Understory: Magnolia virginiana, Persea palustris, Cyrilla racemiflora

• Environmental factors

  • Brownwater rivers (also called redwater rivers)—originate in the Piedmont or Mountains, contain sediment

  • Blackwater rivers: originate in the Coastal Plain, lack sediment, but high in tannins—acidic, dark, and clear

  • Which type has a greater diversity of species? → Brownwater (blackwater is acidic and lacks sediment)

  • Wet and low-lying

  • Fires are not a factor (too wet to burn)

  • important habitat for birds like prothonotary warbler

  • Notice, also, that the species in brownwater Bottomland Hardwoods are common species of the Piedmont, and (not surprisingly), blackwater Bottomland Hardwoods have species that are more restricted to the Coastal Plain.

• Disturbance regime

  • logged extensively for valuable timber

  • hurricanes

• Threats

  • Habitat loss

    • conversion to agriculture

    • timber harvest

    • development

  • Invasive species

    • emerald ash borer