Bay forest is used to describe communities dominated by a number of bay trees (Christensen 1988). The Nature Conservancy's Southeastern United States Ecological Community Classification (Allard 1990) and state classification systems for North Carolina and South Carolina use this name to describe the community (Nelson 1986, Schafale and Weakley 1990) and mention the synonyms evergreen bay and bay pocosin. State classification schemes refer to this community as sweetbay forest (Pell 1984, Smith 1988), and red bay-sweet bay community (Penfound 1952) in Louisiana; bayhead forest (Wieland 1994) in Mississippi; and baygall (FNAI and Florida Department of Natural Resources [FDNR] 1990) in Alabama and Florida; Coastal Plain bog/seep forest when dominated by bays (Wharton 1978) in Georgia; and oligotrophic saturated forest (Rawinski 1990; cross-classified in Allard 1990) in Virginia.
Bay forests may generally be divided into those that occur on seepage slopes and those that occupy basins or non-alluvial wetlands. Those on seepage slopes share many physical characteristics with streamhead pocosins and those in basins with the other pocosin types and peatland forests. The distinction is sometimes important for management considerations.
Range/Current Distribution
This community occurs predominantly in the outer Coastal Plain (Landaal 1991a). Other occurrences are in the middle Coastal Plain, sandhills, and lower piedmont (Landaal 1991a, Schafale and Weakley 1990). The community type extends from Virginia south to Florida, and west to eastern Texas (Christensen 1988). The community also occurs in Arkansas (Landaal 1991a).
Environmental Factors
Topographic Position
Bay Forests typically occur at drainages and edges of sandhill streams, depressions in sandhills, Carolina bays (Landaal 1991a), edges of floodplains where there is groundwater seepage (Wharton 1978), and poorly drained interstream flats (Schafale and Weakley 1990). They occur on margins of deep gum and cedar swamps in the Great Dismal Swamp and in shallow cut-over cypress swamps in the Okefenokee Swamp. They can occur in shallow organic deposits and deeper peats (Schafale and Weakley 1990).
Hydrology
Bay forests are continually to seasonally saturated and infrequently flooded (Landaal 1991a, Schafale and Weakley 1990). Hydrologic inputs are from perched water tables, seepage from adjacent slopes, and rainfall, unless the community is associated with a stream (Landaal 1991a).
Natural Disturbance Regime
The community is late successional and is not maintained by disturbance (Landaal 1991a, Schafale and Weakley 1990). Saturated soils decrease the occurrence of fire. Fires that do occur are more intense when abundant vegetative biomass is present (Landaal 1991a).
Soil
Soils are strongly acidic and sandy, with a surface layer of peat. The peat can be as deep as 2 m and is high in organic matter content. In occurrences in Carolina bays and possibly elsewhere, a perched water table is maintained by an impervious layer beneath the soil (Landaal 1991a).
Physiognomy/Structure
Bay Forests are broad-leaved evergreen forests that are low in stature (for example, 3 to 10 m in height in the Green Swamp, NC) relative to surrounding forest types. The canopy is dense and there exists a subcanopy of vines and tall shrubs (Landaal 1991a). The shrub layer in North Carolina is dense to somewhat open (Schafale andWeakley 1990). The herb layer is sparse, but sphagnum moss may be abundant. Tree roots are frequently exposed (Landaal 1991a).
Commonly Associated Plant Communities
Pond pine woodlands, non-riverine swamp forest, AWC forest and high and low pocosins often occur in a mosaic with bay forests (Landaal 1991a, Schafale and Weakley 1990, Wharton 1978).
Successional Relationships
This community is believed to be late successional, succeeding AWC swamp forest (Buell and Cain 1943) and pond pine woodland after a long period without fire. If the water table is high and there is a deep, peat-burning fire, a sedge bog can develop if fire continues to be frequent. When the water table is low, a deciduous bay forest may develop after a deep peat burn. A shallow peat burn can lead to the development of AWC swamp forest or a pond pine woodland if the seed bank contains these species (Christensen 1988, Landaal 1991a, Buell and Cain 1943). However, the community dominants recover quickly following fire, and may recover from less severe burns (Schafale and Weakley 1990).
Biological Composition
The community is characterized by the canopy dominance of one or more of the following: loblolly bay (Gordonia lasianthus), sweet bay (Magnolia virginiana), and swamp red bay (Persea palustris) (Landaal 1991a), but other species found in association with bay trees vary across the region (Christensen 1988). In North Carolina, pond pine (Pinus serotina), swamp tupelo (Nyssa biflora), red maple (Acer rubrum), loblolly pine (Pinus taeda), and AWC may be significant components of the canopy and sub-canopy in addition to the dominant bay species (Schafale and Weakley 1990). In Florida, pond pine, slash pine (Pinus elliottii), longleaf pine (Pinus palustris), and bald cypress (Taxodium distichum) occur in bay forests. Canopy dominants in Texas bay forests include swamp laurel oak (Quercus laurifolia), black gum (Nyssa sylvatica), sweet bay, yaupon (Ilex i) and red maple (Christensen 1988). In Louisiana, the canopy is similar to that in Texas, with the addition of pond cypress (Taxodium ascendens), slash pine, and longleaf pine. The shrub layer can be diverse, including titi (Cyrilla racemiflora), fetter-bush (Lyonia lucida), sweet gallberry (Ilex coriacea), bitter gallberry (I. glabra), evergreenbayberry (Myrica heterophylla), black highbush blueberry (Vaccinium atrococcum), highbush blueberry (V. corymbosum), zenobia (Zenobia pulverulenta) (Christensen 1988), wax myrtle (Myrica cerifera), male-berry (Lyonia lugustrina), leucothoe (Leucothoe axillaris, L. racemosa), Virginia willow (Itea virginica), red chokeberry (Sorbus arbutifolia), possum-haw viburnum (Viburnum nudum), poison sumac (Rhus vernix), sweet pepperbush (Clethra alnifolia), hazel alder (Alnus serrulata), American snowbell (Styrax americana), summer azalea (Rhododendron serrulatum), wild azalea (Rhododendron oblongifolium) (Smith 1988), and sparkle berry (Vaccinium corymbosum) (Ewel, Davis, and Smith 1989). Vines, including greenbriar (Smilax spp.), Carolina jessamine (Gelsemium sempervirens) and Virginia creeper (Parthenocissus quinquefolia) are important components of bay forests (Christensen 1988). Herb species include netted chainfern (Woodwardia areolata), cinnamon fern (Osmunda cinnamomea), and royal fern (Osmunda regalis) (Landaal 1991a, Christensen 1988).