Cliffs, Talus, Buttes and Badlands: Eastern Dry Alkaline Cliffs Thuja occidentalis / Carex eburnea - Pellaea atropurpurea Woodland Nor<strong>the</strong>rn White-cedar / Bristleleaf Sedge - Purple Cliffbrake Woodland Appalachian Cliff White-cedar Woodland CEGL002596 DESCRIPTION: Stands are dominated by coniferous trees, but with a significant amount <strong>of</strong> deciduous species. The most abundant tree species are Thuja occidentalis, Acer saccharum, Tsuga canadensis, Juniperus virginiana, Quercus alba, Quercus muehlenbergii, and Quercus rubra. O<strong>the</strong>r associates include Quercus coccinea and Liriodendron tulipifera in more sou<strong>the</strong>rn stands, and Celtis occidentalis and Ulmus rubra in more nor<strong>the</strong>rn stands. Shrub and small tree species include Cercis canadensis, Cornus florida, Hydrangea arborescens, Ostrya virginiana, and Rhus aromatica. Closed-canopy stands have very few vascular species in <strong>the</strong> lower strata, while stands with broken canopies contain scattered shrubs and a substantial number <strong>of</strong> herbaceous species. Composition is quite variable, but some <strong>of</strong> <strong>the</strong> most constant herbaceous plants include Asarum canadense, Carex eburnea, Cystopteris bulbifera, and Hepatica nobilis var. acuta (= Hepatica acutiloba) (Anderson 1996). In Kentucky, Thuja occidentalis occurs within <strong>the</strong> Cumberland River drainage in <strong>the</strong> sou<strong>the</strong>astern Highland Rim region. These woodlands are associated with steep, rocky, limestone, mostly north- and east-facing slopes along permanent streams. Some stands are associated with cold-air drainages. These sites are small (0.1-1 acre), with scattered Thuja occidentalis codominating with Acer saccharum, Fraxinus americana, Ostrya virginiana, and Philadelphus hirsutus. O<strong>the</strong>r associated species include Juniperus virginiana var. virginiana, Cercis canadensis var. canadensis, Pachysandra procumbens, Hamamelis virginiana, Par<strong>the</strong>nocissus quinquefolia, Solidago flexicaulis, Solidago sphacelata, Symphyotrichum cordifolium (= Aster cordifolius), and Dioscorea quaternata. This community is found primarily on steep calcareous cliffs, as well as on <strong>the</strong> uplands above <strong>the</strong> cliffs. The bedrock is typically limestone or dolomite (Braun 1928a, Anderson 1996). Soils are shallow, dry, and calcareous, and plants <strong>of</strong>ten root in crevices or on narrow ledges, or adjacent clifftops and talus. In <strong>Ohio</strong> this woodland community occurs as pure, isolated patches on steep calcareous cliffs. It is also found as mixed stands on <strong>the</strong> uplands above <strong>the</strong> cliffs. The site <strong>of</strong> a glacial relict stand in <strong>Ohio</strong> is maintained by seepage springs from underground limestone formations (Kangas 1989). In Kentucky, Thuja occidentalis occurs within <strong>the</strong> Cumberland River drainage in <strong>the</strong> sou<strong>the</strong>astern Highland Rim region. These woodlands are associated with steep, rocky, limestone, mostly north- and east-facing slopes along permanent streams. Some stands are associated with cold-air drainages. COMMENTS: 2, MCS. This type is simply defined by <strong>the</strong> presence <strong>of</strong> white-cedar or mixed white-cedar - hardwoods, and ei<strong>the</strong>r forest or woodland canopy; hence all four physiognomic categories fall under this one type. Small-scale occurrences are worth documenting. The relationship between this type and Thuja occidentalis / Carex eburnea Forest (CEGL006021) should be examined and clarified. Stands on lower slopes <strong>of</strong>ten grade into swamps, especially those dominated by Thuja occidentalis. There are also many similarities between this vegetation and that in <strong>the</strong> I.C.3.N.a Thuja occidentalis - Betula alleghaniensis Forest Alliance (A.417). In <strong>the</strong> Ridge and Valley <strong>of</strong> Virginia, Thuja occidentalis communities occur in two situations: on rocky bluffs with admixtures <strong>of</strong> hardwood species and on mesic slopes with Tsuga canadensis and Pinus strobus (G. Fleming pers. comm. 1999). Sou<strong>the</strong>rn Thuja stands are more genetically diverse than nor<strong>the</strong>rn populations (Walker 1987). One Tennessee site is a proposed State Natural Area, Window Cliffs. This association is peripheral in <strong>the</strong> Sou<strong>the</strong>rn Blue Ridge <strong>of</strong> Tennessee. CONSERVATION RANK: G2G3. There are probably fewer than 50 occurrences <strong>of</strong> this community rangewide. It is restricted to north-facing calcareous bedrock cliffs and summits in <strong>the</strong> Ridge and Valley section <strong>of</strong> <strong>the</strong> central Appalachians. About 10 occurrences are known in Virginia and West Virginia, with a total acreage <strong>of</strong> about 120 acres. It is also known from Pennsylvania, Tennessee, and Maryland. Due to <strong>the</strong>ir location on small ledges <strong>of</strong> steep cliffs, <strong>the</strong>se communities are difficult to survey, and few field surveys have been conducted. This community has probably always been rare, and <strong>the</strong>re are no imminent threats. In <strong>Ohio</strong>, <strong>the</strong> type has apparently always been restricted to a few stands. DISTRIBUTION: This white-cedar cliff woodland type is found in <strong>the</strong> Appalachian and Allegheny Plateau region <strong>of</strong> <strong>the</strong> United States. USFS ECOREGIONS: 222Ea:CCC, 222Eb:CCC, 222Ej:CCC, 222Fd:CCC, 222Ha:CCC, 222Hb:CCC, 222Hc:CCP, 231Ak:CCC, M221Aa:CCC, M221Ab:CCC, M221Bd:CC, M221Be:CCC, M221Dd:CCC CONSERVATION REGIONS: 44:C, 45:C, 50:C, 51:C, 52:C, 59:C STATES: KY MD OH PA TN VA WV PROVINCES: MIDWEST HERITAGE SYNONYMY: OH arbor vitae-mixedwood forest = OTHER SYNONYMY: Arbor vitae forest (Braun 1928a) = USNVC HIERARCHY: THUJA OCCIDENTALIS WOODLAND ALLIANCE (II.A.4.N.b) PLANT COMMUNITIES OF THE MIDWEST – 2001. APPENDIX: ASSOCIATION DESCRIPTIONS 336
Cliffs, Talus, Buttes and Badlands: Eastern Moist Alkaline Cliffs Limestone - Dolostone <strong>Midwest</strong> Moist Cliff Sparse Vegetation Limestone - Dolostone <strong>Midwest</strong> Moist Cliff Sparse Vegetation <strong>Midwest</strong> Moist Limestone - Dolostone Cliff CEGL002292 DESCRIPTION: The vegetation is generally quite sparse (
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