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Cedar Barrens

East Tennessee vegetation, if allowed to grow unimpeded, is nearly always forest. One of the exceptions to this forest dominance is a type of prairie called a cedar barrens (or just barrens). University of Tennessee ecologist Dr. H. R. De Selm defined these as areas dominated by native perennial grasses with scattered red cedar trees (Juniperus virginiana). Perennial grass areas on cedar barrens are often mixed with rockier areas with annual grasses. Big blue stem (Andropogon gerardii), little blue stem (Schizarchyrium scoparium), and Indian grass (Sorghastrum nutans) are the main perennial prairie grasses in ORR barrens. Also, a regionally uncommon prairie grass, side-oats grama (Bouteloua cutipendula), grows in the ORR barrens.

Barrens contain very thin soils over limestone rocks. Grass roots are better adapted than tree roots to growing on these soils, allowing prairie grasses to out-compete the trees. In the past these grasses were also maintained by fires. Fires burn much less area now than in the past because many de facto firebreaks such as roads dot our landscape. The grasses on some barrens are now, however, helped by infrequent mowing that is usually done to maintain utility right-of-ways.

Cedar barrens are rare and rapidly disappearing with on-going land development. The most significant ORR barrens was on land that has been sold and mostly bulldozed. Currently barrens are found on the ORR south of Black Oak Ridge, at the south-west end of Haw Ridge (the Raccoon Creek Barren), and in the Bethel Valley area shown below.

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All photos by Mike Ryon.

The ORR barrens are threatened by invasive exotic pest plants. The worst of these are autumn olive (Elaeagnus umbellata) and sericea (Lespedeza cuneata). Under An Invasive Plant Management Plan that has been developed for the ORR, resource managers are actively working to remove infestations of these problem plants.

Along with the grasses many other plants that have evolved to survive in harsh conditions thrive in these unique ORR barrens. These plants include some species that seem more likely to be found in deserts, such as prickly pear cactus (Opuntia humifusa) and two members of the agave family, a yucca (Yucca filamentosa) and false aloe (Manfreda virginica). Flowering plants including nodding onion (Allium cernuum), palespike lobelia (Lobelia spicata), rose pink (Sabatia angularis), and rosin-weed (Silphium asteriscus) give color to the barrens. Other species found on them include limestone adder's tongue fern (Ophioglossum englelmanii).

The world’s largest population of the Tennessee-listed tall larkspur (Delphinium exaltatum) grows in the ORR barrens. Other regionally uncommon plants found there include Culver's root (Veronicastrum virginicum), prairie dock (Silphium terebinthinaceum), milk vetch (Astragalus canadensis), grooved yellow flax (Linum sulcatum), gray coneflower (Ratibita pinnata), and whorled mountain-mint (Pycnanthemum verticillatum).

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Last Updated: August 3, 2009