Brief Description of the State of Georgia
With an area of approximately 57,000 square miles, Georgia is the largest state east of the Mississippi River. The Georgia landscape runs from the mountains in the north and northeast to the Coastal Plain in the southeast. Georgia’s highest point is Brasstown Bald at 4,784 feet above sea level and its lowest is sea level along the coast. Georgia experiences a humid and subtropical climate with fairly mild winters and hot moist summers. The annual precipitation varies from forty inches in central Georgia to more than seventy-four inches in northeast Georgia.
The state is divided into 5 physiographic provinces, or ecoregions (Keyes et al. 1995): the Cumberland Plateau (also known as the Appalachian Plateau), the Ridge and Valley, the Blue Ridge, the Piedmont, and the Coastal Plain (Map 1.1). The vegetation varies within and among these provinces depending upon soil type, elevation, moisture, and disturbance regimes. In addition to these provinces we found distinct differences in areas such as the Fall Line and coast and used these areas when modeling animal distributions and vegetation mapping.
The Cumberland Plateau is found in the extreme northwestern corner of Georgia. It includes Lookout, Pigeon, and Sand Mountains. The province is mostly forested, primarily with mixed oak and oak-hickory communities. The geologic strata include Mississippian-age limestone, sandstone, shale, and siltstone, and Pennsylvanian-age shale, siltstone, sandstone, and conglomerates.
The Ridge and Valley Province occupies most of the northwestern area of Georgia. It came about as a result of extreme folding and faulting events creating a series of roughly parallel ridges and valleys that come in a variety of widths, heights, and geologic materials. These materials include limestone, dolomite, shale, siltstone, sandstone, chert, mudstone, and marble. Caves are relatively numerous in this area. The area includes the Chickamauga Valley, Armuchee Ridges, and the Great Valley. The ridge areas are predominantly forested with stands of oak-hickory and oak-pine. The valleys are mostly agricultural, including a mix of row crop and pasture.
The Blue Ridge Province occupies the northeastern portions of Georgia. The mountain peaks range between 2,000 and 5,000 feet, and are the highest in the state. The southern Blue Ridge is one of the richest centers of biodiversity in the US. The underlying geology is predominantly a mix of igneous, metamorphic and sedimentary geology. A large portion of Blue Ridge in Georgia is Precambrian-age igneous and high-grade metamorphic rocks, the common crystalline rock types include gneiss, schist, and quartzite, covered by well-drained, acidic brownish, loamy soils. Some mafic and ultramafic rocks occur here, producing more basic soils. The vegetation is predominantly made up of oak-hickory and oak-pine communities, with heath balds, hemlock, cove hardwood forests, and some shrub and grass areas. The lower elevation areas of the Blue Ridge are predominantly used for agriculture; large areas are in pasture and used for cattle, hog, and poultry operations. Much of the Blue Ridge is under the ownership of the U.S.D.A. Forest Service in the Chattahoochee National Forest. Urban development has been on the increase in privately-owned portions of the Blue Ridge.
The Piedmont Province cuts across the central portion of Georgia. The region is considered the non-mountainous portion of the Appalachian Highlands and is comprised of a transitional area between the Appalachian Mountains and the coastal plain. It is a complex mosaic of Precambrian and Paleozoic metamorphic and igneous rocks with moderately dissected irregular plains and some hills. The Piedmont contains a series of rolling hills and occasional isolated mountains such as Pine Mountain. The soils of the piedmont tend to be fine textured and in many areas are highly erodible. The area was once highly cultivated but has mostly reverted to pine and hardwood woodlands, and, more recently, to urban and suburban settlement.
The Coastal Plain Province cuts across Georgia below the fall line. The Coastal Plain landscape is a low, flat region of well-drained soils with some areas of gently rolling hills and poorly drained flatwoods. The parent material for these soils area Cretaceous or Tertiary-age sands and sandy clays that are marine in origin and usually acidic. The Coastal Plain vegetation is a complex mix of upland flatwoods and many wetland communities including bottomland hardwoods and the Okefenokee Swamp. Much of the current land use is row crop agriculture and intensively managed pine forest. The coastal area is currently experiencing rapid urbanization.