Ridge and Valley Shale Barrens
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Appalachian Shale Barrens (NatureServe 2015)
Mid Appalachian Shale Barrens (Platt 1951, Keener 1981)

Central Appalachian Shale Barrens (Fleming 2015)


Northeastern Tennessee (Hawkins, Hancock, Hamblen and Greene Counties) in the Ridge and Valley.

Vegetation Description

The Ridge and Valley Shale Barren system is a small patch community embedded in dry oak-pine woodland and occurs in small canopy openings and is sparsely vegetated with forbs and graminoids.  Often a small stream runs under the downhill edge of the barren (Keener 1983).   Vegetation in the barren typically reaches 10 meters in height at most where stunted trees grow; otherwise, open areas vegetated with grasses and forbs may grow to just over a meter.

Physical Characterization

Ridge and Valley Shale barrens occur in the Shale Valley, Southern Limestone/Dolomite Valleys and Low Rolling Hills and the Southern Sandston Ridges EPA level IV ecoregions (Griffith et. al 1998) but are restricted to areas with exposed shale and siltstone geologies. Tennessee sites resemble the physiognomy of mid-appalachian shale barrens. Barrens typically occur on moderately steep slopes (>20°, in mid Appalachian shale barrens) at mid to low elevations (335-575 meters), facing to the south and west.  The substrate is a loose, fragmented bed of shale channery.  Underlying geologies include Ordivician Sevier and Bays formations, Mississippian and Devonian Chattanooga Shales and Cambrian Rome, Nolichucky, Rodgersville and Pumpkin Valley Shales (Hardeman et. al 1966).  Soils are slightly calcareous and are considered very similar to the “black-top” type, which is characteristically well drained and derived from exposed parent bedrock (Peet 1951).  Little organic material is available at the surface.  Barrens are sparsely vegetated, owing to the high surface temperatures of the exposed shales and siltstones and their low surface-moisture levels.  It is theorized by Platt’s 1951 study of the shale barrens of Maryland, Pennsylvania, West Virginia and Virginia that these set of conditions prevent the colonization of non-adapted species.  However, ample soil moisture is available in lower horizons and there seems to be no preclusion of species due to substrate chemisty.  Additionally, Platt shows that neither steepness of slope nor amount of precipitation contribute to barren conditions.  Barrens are typically under an a few acres in size.

Natural Processes

Edaphic conditions are largely responsible for the maintenance of this system.  Soils are highly erosive and much of the fine organic material filters out of the surface horizons but what seems to be especially consequential are the high temperatures and poor moisture capturing capacity of the surface shale channery.  Conditions prevent the establishment of seedlings which can’t tolerate the heat and drought and are acceptable only to the most heliophytic species (Platt 1951).  Sporadic burning probably occurs but these communities are likely not fire-dependent, perhaps unlike the surrounding woodlands which may well be fire-starved.

Dominant Plants


Acer rubrum (Red Maple)

Carya glabra (Pignut hickory)

Juniperus virginiana (Red cedar)

Pinus virginiana (Virginia pine)

Quercus montana (Chestnut oak)

Ulmus alata (Winged elm)


Schizachyrium scoparum (Little bluestem)

Characteristic Plants


Carya carolinae-septentrionalis (Southern shagbark hickory)

Carya ovata (Shagbark hickory)

Fraxinus americana (White ash)

Quercus rubra (Northern red oak)


Celtis occidentalis (Common hackberry)

Celtis tenuifolia (Dwarf hackberry)

Cercis canadensis (Redbud)

Chionanthus virginicus (Fringe tree)

Cornus florida (Flowering dogwood)

Ostrya virginiana (Hop hornbeam)

Philadelphus hirsutus (Streambank mock orange)

Ptelea trifoliata (Common hoptree)

Rhus copallinum var. latifolia. (Winged sumac)

Staphylea trifolia (American bladdernut)

Symphoricarpos orbiculatus (Buckbrush)

Ulmus rubra (slippery elm)


Parthenocissus quinquefolia (Virginia creeper)

Toxicodendron radicans ssp. radicans (Eastern poison ivy)


Amsonia tabernaemontana (Eastern bluestar)

Andropogon gerardii (Big bluestem)

Andropogon virginicus (Broomsedge)

Arabis laevigata (Smooth rockcress)

Aristolochia serpentaria (Virginia snakeroot)

Asclepias quadrifolia (Fourleaf milkweed)

Campanula divaricata small (Bonny bellflower)

Carex pensylvanica (Pennsylvania sedge)

Cheilanthes lanosa (Hairy lipfern)

Danthonia sericea (Downy danthonia)

Danthonia spicata (Poverty oatgrass)

Dichanthelium boscii (Bosc's panicgrass)

Erigeron pulchellus (Robin's plantain)

Houstonia longifolia (Longleaf summer bluet)

Muhlenbergia tenuifolia (Slender muhly)

Packera antennariifolia (Shale barren ragwort)

Packera obovata (Roundleaf ragwort)

Paronychia argyrocoma (Silvery nailwort)

Polygala paucifolia (Gaywings)

Sedum ternatum (Woodland stonecrop)

Selaginella rupestris (Northern selaginella)

Solidago arguta Harris’ (goldenrod)

Thaspium pinnatifidum (Cutleaf meadowparsnip)

Restricted Plants

Allium oxyphilum (Lillydale onion) (VA) -

Antennaria virginica (Shale barren pussytoes) (VA) -

Calystegia spithamaea ssp. purshiana (Low false bindweed) (NC, SC, VA) –Clematis coactilis (Virginia whitehair leather flower) (VA) – grows in highly exposed areas of barren (Platt 1951)

Eriogonum allenii (Shale barren buckwheat) (VA)- grows in highly exposed areas of barren (Platt 1951)

Helianthus laevigatus (Smooth sunflower) (NC, SC, VA) -

Packera antennariifolia (Shale barren ragwort) (VA) -

Paronychia montana (Mountain nailwort) -

Phlox buckleyi (Swordleaf phlox) (VA)–

Taenidia montana (Mountain pimpernel) (VA)–

Invasive Species

Microstegium vimneum may invade the more shaded margins of these exposed barrens.

Community Variation and Subtypes

NatureServe Association: Quercus prinus - Juniperus virginiana - (Pinus virginiana) / Philadelphus hirsutus - Celtis occidentalis Woodland

1) Woodland barren edge 2) Grass dominated zone 3) exposed, un-vegetated zone 4) herb/grass zone

Associated Natural Communities

Cumberland Enclave Dry/Xeric Calcareous Shaley-LImestone Woodland, Cumberland Plateau Siltstone/Shale Cliff

Similar Communities

Southern Appalachian Montane Cliff and Talus; Central Appalachian Pine-Oak Rocky Woodland; Central Interior Highlands Dry Acidic Glade and Barrens (NatureServe 2015)

Presettlement Distribution and Size

Habitat distribution and total size for this system has likely remained fairly stable.  It may be possible that more widespread fire created more of these barren types but this author does not know of any historical estimates.  Surrounding woodland has changed, along with much of Appalachia, in losing Castanea dentata as a dominant tree in the overstory.  It is likely that logging in the surrounding woodland may have contributed to erosion events that create areas of degraded habitat resembling shale barrens but that are functionally very different.

Present Status

These barrens appear to be fairly scattered and limited in size.  This community is rare is Tennessee and less than 40 sites likely remain.

Representative Sites

Greene Co.: N 36°15'0.47" W 83° 0'22.46"


Extensive ATV trails in the Ridge and Valley shale hills are conspicuous from aerial imagery and mar the landscape and pose threats to barren habitat.  Quarrying may be a danger to some sites located close to roads (Fleming 2013).

Management Considerations

It may be possible that shale barren habitat could be expanded by thinning suitable woodland habitat of woody trees.  Occasional burning of the landscape may help to a small degree in maintaining habitat.

Future Research Needs

Some solid research on the shale barrens of the Mid-Atlantic states has been done by the likes of Fleming, Keener and Platt.  However, little to nothing is known about the shale barrens of the Southern Ridge & Valley in Tennessee.  Baseline work on identifying habitat and performing comprehensive floristic surveys is required along with the collection of plot data.

Previous Studies

To our knowledge, no studies of the flora of these Tennessee shale barrens exist.


Fleming, G.P. "The Natural Communities Of Virginia Classification Of Ecological Community Groups: Appalachian Shale Barrens" Virginia Department of Conservation and Recreation. http://www.dcr.virginia.gov/natural_heritage/natural_communities/ncTIVf.shtml 12 Jan 2015.

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

Kartesz, J.T.. 2013, and continuously updated.  The Biota of North America Program (BONAP). North American Plant Atlas. (http://www.bonap.org/napa.html). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2013. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)].

Keener, Carl S. 1983. "Distribution and biohistory of the endemic flora of the mid-Appalachian shale barrens". The Botanical Review. 49 (1): 65-115

Platt, R. B. 1951. An ecological study of the mid-Appalachian shale barrens and of the plants endemic to them. Ecological Monographs 23:339-358.

Checklist of Plant Species known from this community

Ferns and Fern Allies

Cheilanthes lanosa (Michx.) D.C. Eaton

Selaginella rupestris (L.) Spring


Acer rubrum L.

Acer saccharum Marshall

Carya carolinae-septentrionalis (Ashe) Engl. & Graebn.

Carya glabra (Mill.) Sweet

Carya ovata (Mill.) K. Koch

Juniperus virginiana L.

Pinus echinata Mill.

Pinus virginiana Mill.

Quercus ilicifolia Wangenh.

Quercus marilandica Münchh.

Quercus montana Willd.

Quercus rubra L.

Sassafras albidum (Nutt.) Nees

Sassafras albidum (Nutt.) Nees var. molle (Raf.) Fernald

Ulmus alata Michx.


 Acer leucoderme Small

Amelanchier arborea (Michx. f.) Fernald

Ceancthus americanus L.

Celtis occidentalis L.

Celtis tenuifolia Nutt.

Cercis canadensis L.

Chionanthus virginicus L.

Cornus florida L.

Crataegus intricata Lange var. straminea (Beadle) Palmer

Crataegus uniflora Münchh

Hypericum spathulatum (Spach) Steud

Ostrya virginiana (Mill.) K. Koch

Philadelphus hirsutus Nutt.

Ptelea trifoliata L.

Rhus aromatica Aiton

Rhus copallinum L. var. latifolia Engl.

Rosa carolina L.

Spiraea betulifolia Pall. var. corymbosa(Raf.) Maxim.  

Staphylea trifolia L.

Symphoricarpos orbiculatus Moench         

Ulmus rubra Muhl.

Vaccinium stamineum L

Vaccinium vacillans Kalm ex Torr.


Parthenocissus quinquefolia (L.) Planch.

Toxicodendron radicans (L.) Kuntze ssp. radicans


Andropogon gerardii Vitman

Carex pensylvanica Lam.

Cyperus lupulinus (Spreng.) Marcks ssp. lupulinus

Danthonia sericea Nutt.

Danthonia spicata (L.) P. Beauv. ex Roem. & Schult.

Deschampsia flexuosa (L.) Trin.

Dichanthelium boscii (Poir.) Gould & C.A. Clark

Muhlenbergia capillaris (Lam.) Trin.

Muhlenbergia tenuifolia (Kunth) Trin.

Panicum fasciculatum var. implicatum 

Schizachyrium scoparium (Michx.) Nash var. scoparium

Sorghastrum nutans (L.) Nash


Allium cernuum Roth

Allium oxyphilum Wherry

Amsonia tabernaemontana

Arabis laevigata (Muhl. ex Willd.) Poir. var. burkii Porter

Arabis lyrata L.

Arabis serotina Steele

Aristolochia serpentaria L.

Asclepias quadrifolia Jacq.

Asclepias tuberosa L.

Astragalus distortus Torr. & A. Gray

Baptisia tinctoria (L.) R. Br.

Campanula divaricata Michx.

Calystegia spithamaea (L.) Pursh ssp. purshiana (Wherry) Brummitt

Cunila origanoides (L.) Britton

Clematis coactilis (Fernald) Keener

Clitoria mariana L.

Comandra umbellata (L.) Nutt.

Commelina erecta L.

Commelina erecta L. var. angustifolia (Michx.) Fernald

Coreopsis major Walter

Draba ramosissima Desv.

Erigeron pulchellus Michx.

Eriogonum alleni S. Watson

Euphorbia corollataL.

Hedeoma pulegioides (L.) Pers.

Houstonia longifolia Gaertn.

Lechea racemulosa Michx.

Lespedeza procumbens Michx.  

Malaxis bayardii Fernald

Oenothera argillicola Mack.

Packera antennariifolia (Britton) W.A. Weber & Á. Löve

Packera obovate (Muhl. ex Willd.) W.A. Weber & Á. Löve

Paronychia argyrocoma (Michx.) Nutt.

Paronychia fastigiata (Raf.) Fernald

Paronychia montana (Small) Pax & K. Hoffm.

Paronychia virginica Spreng.

Phlox buckleyi Wherry

Phlox subulata L. ssp. brittonii (Small) Wherry

Polygala paucifolia Willd.

Polygonatum biflorum  (Walter) Elliott

Polygonum tenue Michx.

Potentilla canadensis L.

Potentilla simplex Michx.

Sedum glaucophyllum R.T. Clausen

Sedum telephioides (Michx.) H. Ohba

Sedum ternatum Michx.

Silene caroliniana Walter ssp. pensylvanica (Michx.) R.T. Clausen

Solidago arguta Aiton var. harrisii (Steele) Cronquist

Taenidia integerrima (L.) Drude

Taenidia montana (Mack.) Cronquist

Tephrosia virginiana (L.) Pers.

Thaspium pinnatifidum (Buckley) A. Gray

Trichostema brachiatum L.

Trifolium virginicum Small ex Small & Vail

Viola pedata L.

Viola pedata L. var. lineariloba DC.

Viola pedatifida G. Don