Approximately 200 million years ago crustal movements thrust the rocks of the Southern Appalachian region into mountains. After the crustal disturbance during the Paleozoic era, the mountains were worn down by erosion and weathering that reduced the mountains to plains or small hills. These plains were then raised which created opportunities for further erosion. The climate of the Appalachians varies considerably with location and elevation. Temperatures can drop substantially between lower elevations and mountain peaks.
Higher elevations experience greater cloud cover, relative humidity, and precipitation.
Many areas in the Southern Appalachians receive large amounts of precipitation. Cloud cover and fog frequently occur throughout the Southern Appalachians, contributing to the high humidity levels in the region. The Southern Appalachian Region contains a diverse assortment of ecosystems. The higher elevations of the southern mountains support habitats more similar to the boreal forests of the North than to any other habitat in the South. Other ecosystems also found in the Southern Appalachians include cove forests, pine-oak forests, hardwood forests, grassy balds, and heath balds.