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CEGL006923 Tsuga canadensis - Quercus prinus - Betula lenta Forest

The U.S. National
Vegetation Classification
Type Concept Sentence:
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Common (Translated Scientific) Name: Eastern Hemlock - Chestnut Oak - Sweet Birch Forest
Colloquial Name: Central Appalachian Hemlock - Chestnut Oak Forest
Hierarchy Level: Association
Type Concept: This association is a hemlock - mixed oak forest which often occurs on steep northeastern to northwestern exposures. It ranges from the New Jersey Highlands south to the Blue Ridge, Ridge and Valley, Cumberlands, and Piedmont provinces of Maryland and West Virginia. Occurrences in West Virginia are known from the Bluestone River Gorge and are likely elsewhere. Stands occur at elevations from 150 m to about 750 m (500-2500 feet) on moderately to very steep, sheltered slopes. Northerly aspects and middle slope positions prevail among documented examples. Some sites are "boulderfields" with up to 60% cover by large rocks. Geologic substrate is variable. Soils are usually very stony to extremely stony sandy loams, consistently oligotrophic, with very low pH and base status. Stands of this association are typically floristically depauperate and generally dominated by variable combinations of Quercus prinus and Tsuga canadensis. Betula lenta and, less commonly, Quercus velutina, Quercus coccinea, and Quercus rubra are major overstory associates, each attaining codominance in a subset of stands. Quercus alba, Acer rubrum, Liriodendron tulipifera, Pinus strobus, Sassafras albidum, and Fagus grandifolia are minor overstory associates. Small trees and shrubs can be absent or sparse due to dense shading by hemlock, with Hamamelis virginiana most consistently providing moderate cover. Less frequently, Kalmia latifolia, Rhododendron maximum, and Viburnum acerifolium are shrub components. At some New Jersey sites, a single dense stratum or multiple open strata of ericaceous species can develop, including Rhododendron maximum, Kalmia latifolia, Gaylussacia baccata, and Vaccinium pallidum. The herb layer of this community is typically very sparse or absent; typical scattered species include Maianthemum canadense, Dennstaedtia punctilobula, Chimaphila maculata, Deschampsia flexuosa, Carex swanii, and Aralia nudicaulis.
Diagnostic Characteristics: No Data Available
Rationale for Nominal Species or Physiognomic Features:
Classification Comments: Because of devastation by hemlock woolly adelgid, understory hemlock is often all that's left in this community in Virginia. The original description was based on A. Windisch's (1993) Picatinny Arsenal Hemlock-Mixed Oak-(Heath) Cool Sub-Mesic forest description (TcQf). An expanded circumscription is based on analysis of data from 20 Maryland and Virginia plots, data from Delaware Water Gap, and 9 West Virginia plots. Analysis of more than 1300 montane Virginia plots indicated that the two Virginia plots originally assigned to this type in the National Capital Region analysis are cove plots that are better classified as Tsuga canadensis - Quercus prinus - Liriodendron tulipifera / Kalmia latifolia - (Rhododendron catawbiense) Forest (CEGL008512) (Fleming and Patterson 2009b).
Similar NVC Types:
Physiognomy and Structure: No Data Available
Floristics: This association is a hemlock - mixed oak forest dominated by Tsuga canadensis in association with species of Quercus and other deciduous trees indicative of relatively dry, infertile soils. Stands are typically floristically depauperate and generally dominated by variable combinations of Quercus prinus and Tsuga canadensis. Betula lenta and, less commonly, Quercus velutina, Quercus coccinea, Quercus alba, and Quercus rubra are major overstory associates, each attaining codominance in a subset of stands. Acer rubrum, Liriodendron tulipifera, Pinus strobus, Sassafras albidum, and Fagus grandifolia are very minor overstory associates. Oxydendrum arboreum and Acer saccharum, along with overstory species, may be present in the subcanopy. Small trees and shrubs are often absent or sparse due to dense shading by hemlock, with Hamamelis virginiana most consistently providing moderate cover. Less frequently, Kalmia latifolia, Rhododendron maximum, Vaccinium pallidum, Amelanchier arborea, and Viburnum acerifolium are shrub components. At some New Jersey sites, a single dense stratum or multiple open strata of ericaceous species can develop, including Rhododendron maximum, Kalmia latifolia, Gaylussacia baccata, and Vaccinium pallidum. The herb layer of this community is typically very sparse or absent with scattered individuals of a few species; typical species vary somewhat with geography and include Maianthemum canadense, Dennstaedtia punctilobula, Dioscorea quaternata, Chimaphila maculata, Deschampsia flexuosa, Dryopteris marginalis, Chimaphila maculata, Carex swanii, Eurybia divaricata, Goodyera pubescens, Gaultheria procumbens, Mitchella repens, Monotropa hypopithys, Monotropa uniflora, Parthenocissus quinquefolia, and Aralia nudicaulis. In nine West Virginia plots, vascular plant richness ranged from 16 to 43 (mean = 26.5) species per 400-square-meter plot.
Dynamics: Extensive hemlock mortality caused by hemlock woolly adelgid (Adelges tsugae) is changing the composition of many of these forests. Most Maryland stands are now in a degraded condition, and some have suffered virtually complete hemlock mortality. In Bluestone National Scenic River (WV), many hemlocks appear stressed, but large scale mortality was not observed during the 2003-2006 vegetation surveys.
Environmental Description: Stands occur at elevations from 150 m to about 750 m (500-2500 feet) on moderately to very steep, sheltered slopes. Northern to northwestern aspects and middle slope positions prevail among documented examples. Some sites are "boulderfields" with up to 60% cover by large rocks; some appear above or below cliff bands. Geologic substrate is variable but includes shales and sandstone. Soils are usually very stony to extremely stony sandy loams, consistently oligotrophic, with very low pH and base status. Soils in eight West Virginia plots in the environs of Bluestone National Scenic River are described as dry to somewhat moist, well-drained, stone-free to very stony sandy loam, silt loam, sandy silt loam, and sandy clay loam; they tested extremely to medium acidic (mean pH = 4.4) with relatively high levels of organic matter, estimated N release, S, Al, B, and Fe and relatively low levels of Ca, Cu, K, Mg, Mn, P, and Zn compared to average values in the area.
Geographic Range: This association ranges from the New Jersey Highlands south to the Blue Ridge, Ridge and Valley, and Piedmont provinces of Pennsylvania and Maryland, and the Cumberlands in West Virginia.
Nations: US
States/Provinces: MD, NJ, NY, PA, WV
US Forest Service Ecoregions (1994/1995)
Domain Name:
Division Name:
Province Name: Laurentian Mixed Forest Province
Province Code: 212    Occurrence Status: Predicted or probable
Section Name: Northern Ridge and Valley Section
Section Code: M221A     Occurrence Status: Predicted or probable
Omernik Ecoregions:
Confidence Level: Moderate
Confidence Level Comments:
Grank: G3
Greasons: While this association does not appear to be intrinsically rare, it occurs in small patches in very specific habitats, and its viability is critically threatened by the spread of hemlock woolly adelgid.
Concept Lineage:
Predecessors:
Obsolete Names:
Obsolete Parents:
Synonomy: > Picatinny Arsenal Hemlock-Mixed Oak-(Heath) Cool Sub-Mesic forest description (TcQf) (Windisch 1993)
Concept Author(s): A. Windisch, mod. L.A. Sneddon and S.C. Gawler, mod. G. Fleming
Author of Description: A. Windisch, S.C. Gawler and G.P. Fleming
Acknowledgements:
Version Date: 24Feb2010
References:
  • Eastern Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boston, MA.
  • Edinger, G. J., D. J. Evans, S. Gebauer, T. G. Howard, D. M. Hunt, and A. M. Olivero, editors. 2002. Ecological communities of New York state. Second edition. A revised and expanded edition of Carol Reschke's ecological communities of New York state. (Draft for review). New York Natural Heritage Program, New York State Department of Environmental Conservation, Albany, NY.
  • Edinger, G. J., D. J. Evans, S. Gebauer, T. G. Howard, D. M. Hunt, and A. M. Olivero, editors. 2014. Ecological communities of New York state. Second edition. A revised and expanded edition of Carol Reschke's ecological communities of New York state. New York Natural Heritage Program, New York State Department of Environmental Conservation, Albany, NY.
  • Fike, J. 1999. Terrestrial and palustrine plant communities of Pennsylvania. Pennsylvania Natural Diversity Inventory. Pennsylvania Department of Conservation and Recreation, Bureau of Forestry, Harrisburg, PA. 86 pp.
  • Harrison, J. W. 2011. The natural communities of Maryland: 2011 working list of ecological community groups and community types. Unpublished report. Maryland Department of Natural Resources, Wildlife and Heritage Service, Natural Heritage Program, Annapolis. 33 pp.
  • Harrison, J. W., compiler. 2004. Classification of vegetation communities of Maryland: First iteration. A subset of the International Classification of Ecological Communities: Terrestrial Vegetation of the United States, NatureServe. Maryland Natural Heritage Program, Maryland Department of Natural Resources, Annapolis. 243 pp.
  • Perez, John. Personal communication. Biologist, USDI National Park Service, Glen Jean, WV.
  • Perles, S. J., G. S. Podniesinski, E. A. Zimmerman, E. Eastman, and L. A. Sneddon. 2006d. Vegetation classification and mapping at Allegheny Portage Railroad National Historic Site. Technical Report NPS/NER/NRTR--2006/079. National Park Service, Philadelphia, PA.
  • Perles, S. J., G. S. Podniesinski, E. Eastman, L. A. Sneddon, and S. C. Gawler. 2007. Classification and mapping of vegetation and fire fuel models at Delaware Water Gap National Recreation Area. Technical Report NPS/NER/NRTR--2007/076. National Park Service, Philadelphia, PA. 2 volumes.
  • Vanderhorst, J. P., B. P. Streets, J. Jeuck, and S. C. Gawler. 2008. Vegetation classification and mapping of Bluestone National Scenic River, West Virginia. Technical Report NPS/NER/NRTR--2008/106. National Park Service, Philadelphia, PA.
  • Windisch, A. G. 1993. Natural community inventory of Picatinny Arsenal, New Jersey. Unpublished report prepared for Picatinny Arsenal, U.S. Department of Defense. The Nature Conservancy, Eastern Heritage Task Force, Trenton, NJ.
  • WVNHP [West Virginia Natural Heritage Program]. No date (b). Unpublished data. West Virginia Natural Heritage Program, Elkins.