Southern Appalachian Rocky Summit (NatureServe 2014)
High Elevation Rocky Outcrop (Typic Subtype) (Shafale 2012)
Northeastern Tennessee (Carter and Unicoi counties) on the mid to high slopes of Flint Mountain, White Rocks Mountain, Ripshin Ridge and Unaka Mountain (?).
This is a small patch community, often largely un-vegetated, occurring in a matrix of deciduous oak forest (Pittillo et. al 1998). Vegetation typically reaches less than a meter in height and high-elevation outcrops elsewhere in the Blue Ridge are generally typified by “shrub thickets, herbaceous mats and lithophytic lichens” (Fleming 2009).
Blue Ridge mid-high elevation granite outcrops occur within the Southern Igneous Ridges and Mountains EPA level IV ecoregion (Griffith et. al 1998). They are found at elevations between (750-1500m) on slopes with a typically southerly aspect (Wiser et. al 1996). The geology is composed of igneous and metamorphic rocks, Precambrian in age, of the Beech and Cranberry Granite formations (Hardeman et. al, 1996). Soils of Blue Ridge outcrops, when present, are inceptosols derived from weathering of exposed granite bedrock. Excessively drained, they have little water holding capacity and are typically acidic (Pittillo et al 1998). Flint Mountain outcrops are in a matrix of Burton-Wayah Complex soils, on 20-80% slopes. Unaka Mountain outcrops occur in soils of Spivey Cobbly Loam at a 20-80% slopes, Ripshin Ridge outcrops on Chestnut Loam at 35-50% slopes and White Rocks Mountain outcrops on Cleveland Fine Sandy Loam at 50-80% slopes (Web Soil Survey, 2015).
This system is maintained by edaphic conditions in combination with high elevation conditions (high solar radiation and dessication from high winds) (NatureServe 2014). Granite is also known to weather by a process in which outer layers of exposed granite exfoliate due to thermal expansion and contraction of water trapped in surficial cracks.
Community Variation and Subtypes
1) forest-outcrop edge: dominated by ericaceous shrubs, otherwise barren species in thinner soil; 2) deep-soil fissures: may be occupied by stunted tree species; 3) pavement outcrop: dominated by lithophytic lichens and scattered or patchy mats of xerophytic herbs (Fleming 2015).
Associated Natural Communities
Blue Ridge Granite Cliff, Blue Ridge High-Elevation Rocky Granite Shrubland
Blue Ridge High-Elevation Metasandstone Outcrop
Presettlement Distribution and Size
This system has likely retained its historic range and exists in much the same state it always has.
This system is restricted to the slopes of Flint Mountain, White Rocks Moutain, Ripshin Ridge, and Unaka Mountain.
Carter Co.: White Rocks Mountain (36.218408, -82.102736)
Anthropogenic disturbance in the form of trampling may possibly have small effect on the integrity of the system. Fire suppression in the surrounding woodlands and forest has probably limited the extent of open habitat throughout the mountains of eastern Tennessee.
Prescribed burning might open up habitat and increase chances for erosion of thin soils, perhabs expanding outcrop habitat.
Future Research Needs
Baseline investigation on the floristic composition of this system in Tennessee is required; plot work would inform community classifications.
Granite outcrops have been well studied in adjacent states (Fleming 2015, Wiser 1996, Wyatt 2000) but little to no work has been done on the system in Tennessee (Donaldson, Levy, personal communication, April 21-26, 2015).
Caspary, Melissa, and James Affolter. 2013. "Effects of removing exotic invasive species from the ecotones of two granite rock outcrops in the southeastern Piedmont of the United States". Management of Biological Invasions. 4 (3): 235-247.
Donaldson, J. and F. Levy. “Concerning granite outcrop communities of the Blue Ridge,” email messages sent by Chris Mausert-Mooney, April 21-26, 2015.
Fleming, G. P., and K. D. Patterson. 2009a. A vegetation classification for the Appalachian Trail: Virginia south to Georgia. Virginia Department of Conservation and Recreation, Division of Natural Heritage. In-house analysis, March 2009.
Griffith G, Omernik J, Azevedo S. 1998. Ecoregions of Tennessee (color poster with map, descriptive text, summary tables, and photographs): Reston, VA., U.S. Geological Survey (map scale 1:1,000,000).
Hardeman, W.D., and others, 1966, Geologic map of Tennessee: Division of Geology, Tennessee Department of Environment and Conservation, scale 1:250,000
NatureServe. 2014. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://explorer.natureserve.org. (Accessed: February 25, 2015).
Soil Survey Staff, Natural Resources Conservation Service, United States Department of Agriculture. Web Soil Survey. Available online at http://websoilsurvey.nrcs.usda.gov/ . Accessed [05/4/2015].
Wiser, S. K., R. K. Peet, and P. S. White. 1996. "High-elevation rock outcrop vegetation of the Southern Appalachian Mountains". Journal of Vegetation Science : Official Organ of the International Association for Vegetation Science. 7 (5): 703.
Wyatt, Robert, and James R. Allison. "Flora and vegetation of granite outcrops in the southeastern United States." Inselbergs. Springer Berlin Heidelberg, 2000. 409-433.
Checklist of Plant Species known from this community