Piedmont and Coastal Plain
Sites on the coastal plain and Piedmont extend from the southern-most DSNY in Florida and western-most (KINF) in Louisiana up through the central Piedmont (DUKE) and mid-Atlantic states (SERC). Low-lying coastal plain sands and organic soils extend from the continental shelf up to higher ground of the interior highlands (Gulf Coast) and Piedmont. Sandhills mark former aeolian activity, some associated with relic coastal dunes at past sea-level stands. Rolling topography on the Piedmont results from highly weathered igneous and metamorphic bedrock.
There is a profound seasonality gradient within the region. Central Florida (OSBS, DSNY) has highly seasonal precipitation, with almost daily afternoon convection storms in summer months, leading to large moisture surpluses. North and west of central Florida summer deficits are common. Further north on the the Piedmont precipitation is evenly distributed throughout the year but highly variable from year to year.
Vegetation varies with relief/drainage and microclimate. Mesic flatwoods on Coastal Plain sands include DSNY, CROA, and GRSW. This was the historic center of longleaf pine (Pinus palustris). OSBS and CALL are sandhills sites that support pines, xeric oaks (e.g., Quercus laevis), and a mixture of hardwoods. Coastal plain sites supported frequent fire, which is now being managed to promote longleaf pine at a number of sites within MASTIF (CALL, GRSW, OSBS, DSNY). Piedmont sites include a mix of pines and hardwoods at DUKE and TALL, the latter also identified with the interior highlands. Bottomland forests of the coastal plain and Piedmont (DUKE_HW) include a range of hardwood species.
The region includes the long-term network of USFS longleaf pine observations from Dale Brockway, Don Bragg, and Qinfeng Guo (Guo et al. 2016). NEON sites in the SE that are part of this study include DSNY, OSBS, and TALL.
Southeastern sites assimilated thus far include the following:
USFS longleaf network
The Appalachian highlands extend from Alabama to New York. Primarily sedimentary rocks were uplifted during the mid-Paleozoic to Cenozoic, then highly weathered since. Adjacent Blue Ridge and Valley and Ridge provinces hold metamorphic rocks. Peaks extend above 1500 m in elevation.
Appalachian climates are highly variable in space and time. Temperature declines and precipitation increases with elevation. High elevation sites typically have year-round moisture surpluses. At lower elevations summer deficits are common. Aspect affects atmospheric demand, with SW facing slopes supporting more drought-tolerant taxa.
The rich diversity of forests is described in classic papers of Robert Whittaker, among others. Vegetation ranges from xeric pine/oak (Quercus montana, Q. rubra, Q. alba, Q. coccinea, Pinus rigida) forests on ridgelines to high diversity coves (Tsuga canadensis, Acer saccharum, Fraxinus spp., Tilia americana). Still lower elevations support elements of the southern Piedmont and north temperate forests at MARS and SCBI. Strong moisture gradients interact with elevation gradients in temperature and moisture. At low elevations Liriodendron is abundant throughout. With increasing elevation there is a shift to northern hardwoods (Acer saccharum, Fagus grandifolia, Betula alleghaniensis) and spruce-fir (Picea rubens, Abies fraseri). Mountain sites in GRSM extend from mixed hardwoods to highest elevation spruce-fir stands. At CWT highest elevation sites reach northern hardwoods. Lowest elevation sites at GRSM and CWT both extend to mixed Piedmont hardwoods.
Sites assimilated thus far include long-term studies from our group (CWT, GRSM, MARS), Bill McShea’s SCBI plot, and Katie Greenberg’s acorn network that includes Bent Creek:
Bent Creek (BCEF), Grandfather Mtn (GRAN), and Pisgah (PISG)