Classification of Vegetation Communities of Maryland: First Iteration
A Subset of the International Classification of Ecological
Concept: This alliance includes open woodlands of shale barrens and shale ridges in the Allegheny Plateau and Knobs region of Kentucky and Virginia, and possibly ranging into West Virginia. The alliance also includes Quercus prinus-dominated woodlands on the siltstone ridgetops of the Kentucky Knobs region. Canopies are dominated by Quercus prinus, with lesser coverage by Pinus virginiana, Quercus velutina, Quercus coccinea, Carya glabra, and Amelanchier arborea. Other species include Cornus florida, Carya glabra, Carya alba, Vaccinium pallidum, Pityopsis graminifolia var. latifolia, Danthonia spicata, Dichanthelium depauperatum/linearifolium, Aristida dichotoma, Aristida oligantha, and Potentilla canadensis. Some examples may contain Silene caroliniana (ssp. wherryi, or possibly ssp. pensylvanica). Currently this alliance is narrowly defined to cover woodlands associated with shale substrates, but may be expanded if needed.
Comments: Currently only two associations are defined in this alliance. Additional associations for shale woodlands in the central Appalachians will likely be defined within this alliance. A new association may be developed to accommodate the vegetation of the siltstone ridgetops of the Kentucky Knobs region (M. Hines pers. comm.).
Range: This alliance is found in the Allegheny Plateau and Knobs region of Kentucky and Virginia, and possibly ranges into Tennessee (?), West Virginia (?), and elsewhere.
States/Provinces: KY MD? PA? TN? VA WV?
TNC Ecoregions: 44:C, 50:C, 59:C
USFS Ecoregions: 221Ea:CC?, 221Eb:CC?, 222Ei:CCC, 222Ej:CCC, M221Aa:CCC, M221Ab:CCP, M221Da:CCC, M221Dc:CCC
Federal Lands: NPS (Shenandoah); USFS (Daniel Boone, George Washington, Jefferson)
Synonymy: Appalachian sub-xeric forest, in part (Evans 1991); Shale barrens, in part (Evans 1991); Chestnut Oak: 44, in part (Eyre 1980)
References: Evans 1991, Eyre 1980, Hines pers. comm.
Authors: D. TAYLOR, RW, Southeast Identifier: A.622
QUERCUS PRINUS / QUERCUS ILICIFOLIA / DANTHONIA SPICATA - SOLIDAGO BICOLOR WOODLAND
Rock Chestnut Oak / Bear Oak / Poverty Oatgrass - White Goldenrod Woodland
Central Appalachian Xeric Shale Woodland (Rock Chestnut Oak / Mixed Herbs Type) G3? (01-09-21)
Ecological Group (SCS;MCS): Appalachian Shale Glades and Barrens (440-40; 22.214.171.124)
Concept: The known range of this vegetation type includes the extreme north end of the southern Blue Ridge, the northern Blue Ridge, and the Ridge and Valley region of Virginia. The likely global range encompasses the entire central Appalachian extent of these provinces in Virginia, West Virginia, Maryland, and Pennsylvania. Stands are generally confined to low elevations, from 400-840 m (1400-2760 feet), but exceptionally to 1100 m (3600 feet). Habitats are mostly steep, south- to west-facing, middle to upper slopes with abundant outcrops, loose stones, and exposed mineral soils. However, substrates appear to be relatively stable and lack the ongoing erosional processes of shale barrens, which these habitats often border on the landscape. Slope shape is typically convex in at least one direction. Site moisture potential is very low. This community is an open to very open woodland dominated by Quercus prinus. Overstory trees are often stunted and gnarled. Quercus rubra and Carya glabra are constant, usually minor canopy associates that attain codominance with Quercus prinus locally. Pinus virginiana is an important canopy associate in some situations, but is entirely absent from other stands of the type. Understory tree layers are sparse, consisting mostly of younger reproduction of the canopy species. Quercus ilicifolia, Vaccinium stamineum, and Vaccinium pallidum are the chief species of a patchy shrub layer, which may also include Rosa carolina, Amelanchier arborea, and Viburnum rafinesquianum. Quercus ilicifolia usually forms open colonies in this community type, rather than the dense thickets characteristic in pyrophytic pine-oak/heath vegetation. The herb layer is typically quite patchy and sparse, but contains a surprising diversity of xerophytic graminoids and forbs.
Comments: This community type is floristically similar to Pinus virginiana - Quercus prinus / Quercus ilicifolia / (Hieracium greenii) Woodland (CEGL008525) but differs in the dominance of hardwoods (versus Pinus virginiana) and in its much greater herbaceous diversity and overall species richness (n = 33 versus 15). Edaphic stresses are probably the most important ecological factor maintaining this woodland, but many stands have undoubtedly been influenced by periodic fires as well, which may account for some of the compositional differences with CEGL008525. Although soil samples collected from plots of both community types were similar in pH and base status, we suspect that differences in soil fertility, texture, and/or stability may also distinguish these types. More intensive study of the environmental differences between the two units is warranted.
Range: The known range of this vegetation type includes the extreme north end of the southern Blue Ridge, the northern Blue Ridge, and the Ridge and Valley region of Virginia. The likely global range encompasses the entire central Appalachian extent of these provinces in Virginia, West Virginia, Maryland, and Pennsylvania.
States/Provinces: MD?, PA?, VA:S?, WV?
TNC Ecoregions: 50:C, 59:C
USFS Ecoregions: M221Aa:CCC, M221Ab:CCP, M221Da:CCC, M221Dc:CCC
Federal Lands: NPS (Shenandoah); USFS (George Washington, Jefferson)
Synonymy: Quercus prinus / Quercus ilicifolia / Danthonia spicata - Solidago bicolor Woodland (Fleming and Coulling 2001) =, Pinus pungens - Pinus rigida / Quercus ilicifolia / Gaylussacia baccata Association: Andropogon scoparius - Coreopsis verticillata - Dichanthelium depauperatum Subassociation, pro parte (Rawinski et al. 1996). see CEGL008540.
References: Fleming and Coulling 2001, Fleming et al. 2001, Rawinski et al. 1996
Authors: G. Fleming and P. Coulling, ECS Confidence: Identifier: CEGL008526
- Maryland Vegetation Classification Subset Report II. Woodland
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