Ohio subset of Plant Communities of the Midwest ... - NatureServe

Cliffs, Talus, Buttes and Badlands: Eastern Dry Alkaline Cliffs
Thuja occidentalis / Carex eburnea - Pellaea atropurpurea Woodland
Northern 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 of deciduous species. The
most abundant tree species are Thuja occidentalis, Acer saccharum, Tsuga canadensis, Juniperus virginiana,
Quercus alba, Quercus muehlenbergii, and Quercus rubra. Other associates include Quercus coccinea and
Liriodendron tulipifera in more southern stands, and Celtis occidentalis and Ulmus rubra in more northern 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 the lower strata, while stands with
broken canopies contain scattered shrubs and a substantial number of herbaceous species. Composition is quite
variable, but some of the 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 the Cumberland River drainage in the southeastern 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. Other
associated species include Juniperus virginiana var. virginiana, Cercis canadensis var. canadensis, Pachysandra
procumbens, Hamamelis virginiana, Parthenocissus 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 the uplands above the cliffs. The bedrock
is typically limestone or dolomite (Braun 1928a, Anderson 1996). Soils are shallow, dry, and calcareous, and plants
often root in crevices or on narrow ledges, or adjacent clifftops and talus. In Ohio this woodland community occurs as
pure, isolated patches on steep calcareous cliffs. It is also found as mixed stands on the uplands above the cliffs. The
site of a glacial relict stand in Ohio is maintained by seepage springs from underground limestone formations
(Kangas 1989). In Kentucky, Thuja occidentalis occurs within the Cumberland River drainage in the southeastern
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 the presence of white-cedar or mixed white-cedar - hardwoods,
and either 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 often grade into swamps, especially
those dominated by Thuja occidentalis. There are also many similarities between this vegetation and that in the
I.C.3.N.a Thuja occidentalis - Betula alleghaniensis Forest Alliance (A.417). In the Ridge and Valley of Virginia, Thuja
occidentalis communities occur in two situations: on rocky bluffs with admixtures of hardwood species and on mesic
slopes with Tsuga canadensis and Pinus strobus (G. Fleming pers. comm. 1999). Southern Thuja stands are more
genetically diverse than northern populations (Walker 1987). One Tennessee site is a proposed State Natural Area,
Window Cliffs. This association is peripheral in the Southern Blue Ridge of Tennessee.
CONSERVATION RANK: G2G3. There are probably fewer than 50 occurrences of this community rangewide. It is
restricted to north-facing calcareous bedrock cliffs and summits in the Ridge and Valley section of the central
Appalachians. About 10 occurrences are known in Virginia and West Virginia, with a total acreage of about 120
acres. It is also known from Pennsylvania, Tennessee, and Maryland. Due to their location on small ledges of steep
cliffs, these communities are difficult to survey, and few field surveys have been conducted. This community has
probably always been rare, and there are no imminent threats. In Ohio, the type has apparently always been
restricted to a few stands.
DISTRIBUTION: This white-cedar cliff woodland type is found in the Appalachian and Allegheny Plateau region of the
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
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