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Basic Mesic Forest

Sites

Lower slopes, north-facing slopes, ravines, and occasionally well-drained small stream bottoms, with basic or circumneutral soils.

Soils

Deep, well-drained soils with circumneutral or higher pH. Series include Chewacla, Helena, and Wilkes.

Hydrology

Terrestrial, mesic.

Vegetation

Canopy

Canopy dominated by mesophytic trees, primarily Liriodendron tulipifera (Tulip-tree), Fagus grandifolia (American Beech), Quercus rubra (Red Oak) and Acer floridanum (Southern Sugar Maple). Trees typical of better drained bottomland sites, such as Juglans nigra (Black Walnut), Quercus shumardii (Shumard Oak) and Celtis laevigata (Southern Hackberry), may be present.

Understory

Understory may include Cornus florida (Flowering Dogwood), Cercis canadensis (Eastern Redbud), Carpinus caroliniana (American Hornbeam), Ulmus rubra (Slippery Elm), Asimina triloba (Common Pawpaw) and Ostrya virginiana (American Hop-hornbeam). Shrubs may include Viburnum spp. (Viburnum), Lindera benzoin (Northern Spicebush), Euonymus atropurpureus (American Wahoo), Aesculus sylvatica (Painted Buckeye), Hydrangea arborescens (Smooth Hydrangea), Calycanthus floridus (Sweet-shrub), Staphylea trifolia (Bladdernut) and Styrax grandifolia (Bigleaf Snowbell).

Herb Layer

The herb layer is generally dense and very diverse, with species such as Polystichum acrostichoides (Christmas Fern), Polygonatum biflorum (Small Solomon’s-seal), Maiathemum racemosum (Eastern Solomon’s-plume), Arisaema triphyllum (Common Jack-in-the-Pulpit), Actaea racemosa (Common Black-cohosh), Podophyllum peltatum (May-apple), Viola spp. (Violet), Adiantum pedatum (Northern Maidenhair), Sanguinaria canadensis (Bloodroot), Anemone americana (Round-lobed Hepatica), Tiarella cordifolia (Heartleaf Foamflower), Actaea pachypoda (Dolls’-eyes), Asarum canadense (Common Wild Ginger), Corydalis flavula (Short-spurred Corydalis), Hybanthus concolor (Green-violet), Cypripedium parviflorum (Large Yellow Lady’s-slipper), Delphinium tricorne (Dwarf Larkspur), Dicentra cucullaria (Dutchman’s Britches), Enemion biternatum (False Rue-anemone), Lathyrus venosus (Forest Pea) and Trillium cuneatum (Sweet Betsy).

Dynamics

Under natural conditions these forests are uneven-aged, with old trees present. Reproduction occurs primarily in canopy gaps. The natural fire regime of the Piedmont is not known, but fires certainly occurred periodically. Because Basic Mesic Forests generally occur in moist and topographically sheltered sites, they, like Mesic Mixed Hardwood Forests, probably burned only rarely and with low intensity. Disturbed areas have increased amounts of pines and weedy hardwoods such as Liriodendron tulipifera (tulip-tree) and Liquidambar styraciflua (Sweet Gum). Like floodplain forests, these communities are susceptible to invasion by exotic species such as Lonicera japonica (Japanese Honeysuckle) when disturbed.

Associations

Grades into Levee Forest, Bottomland Forest, or Alluvial Forest below. May grade into Basic Oak-Hickory Forest or Xeric Hardpan Forest above. May grade into Mesic Mixed Hardwood Forest or Dry-Mesic Oak-Hickory Forest on more acidic sites.

Comments

This type is similar to the Mesic Mixed Hardwoods community type but differs in its occurrence over basic substrates and greater general species richness. Although basic soils and indicator vegetation are generally associated with mafic rocks, occasional examples occur on apparently acidic rocks. The additional factors necessary to develop a Basic Mesic Forest are not known. It should be noted that soils on lower slopes, even on acidic rocks, generally have a higher pH than those on upper slopes and ridgetops. This is possibly caused by accumulation of leached bases, and it makes the distinction between the effect of moisture status and nutrient status more difficult. Basic substrates appear to allow many lower slope and bottomland species to occur farther upslope, in apparently drier sites. Thus a Basic Mesic Forest community might extend farther upslope than the acidic equivalent, a Mesic Mixed Hardwoods Forest. Because of the limited extent of basic rocks in the Piedmont, these communities are rare. The occurrence of these communities on steep slopes has allowed many of them to escape with less disturbance than many upland communities. The great floristic diversity of these communities makes them of particular botanical interest. They are often sites for rare and disjunct species.