Soil Types in the Carolina Bay

Muck and Shallow Organic Soils

• In wetlands, acidic organic soils develop when leaves, dead trees and shrubs and other plant materials slowly decompose in waterlogged conditions. In the Carolina bays, the decomposed organic materials accumulate inside the depression, may eventually become muck up to nine feet deep, and sometimes fill the bay completely. When shallow organic soils develop over muck in bays, they may support non-riverine swamp trees such as loblolly pine, bald cypress and sweet gum, but can include the wetland pond pine, or Pinus serotina. When these soils are ditched and the bay is drained, the accumulated organic material makes excellent farmland.

Mineral Soils

• Mineral soils in general are composed of sand, silt or clay, with a low percent of organic material, and more specifically, loam soils have roughly equal amounts of sand, silt and clay along with a small amount of humus. Sandy mineral soils occur along the rims of even the deepest mucky bays, and loamy soils develop in shallow bay depressions. Wide bays, from the central muck to the sandy rims, display a continuum of concentric rings of fine loamy to sandy loam soils. In shallow bays with predominantly loamy soils, the dominant vegetation is pond pine.

Deep Sandy Peat

• Peat is the accumulation of brown, decomposed, organic material in acidic bog. Some plant nutrients are only available at more neutral soil pH, so plant growth in peat soil is very slow, and larger trees such as pond pine cannot survive. Carolina bays with peat soil typically support fire-dependent "high pocosin" thickets of dense shrubs such as holly, but in the absence of fire, some pocosin may mature to a climax vegetation of specialized "bay" forest. The peat soils of pocosin communities are the natural habitat of "Venus Flytrap," a small herb.

Deep Organic Soils

• The deepest Carolina bay organic soils support a specialized bay forest that is not easily defined. The dominant trees are members of the Laurel or "Bay" family and include Magnolia virginiana and "Loblolly Bay" Gordonia lasianthus, both of which thrive in acidic fine sandy organic soils, and "Red Bay" Persea palustris, aka borbonia, which is more adaptable and can grow in rich, wet, muck swamps. The bay forest is typically a canopy over pocosin vegetation that has accumulated mounds of deep organic soil.