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CEGL008513 Tsuga canadensis - Betula alleghaniensis / Ilex montana / Rhododendron catawbiense Forest

Type Concept Sentence: No Data Available

Common (Translated Scientific) Name: Eastern Hemlock - Yellow Birch / Mountain Holly / Catawba Rosebay Forest

Colloquial Name: Eastern Hemlock / Catawba Rhododendron Forest

Hierarchy Level:  Association

Type Concept: This community type is known only from seven locations in the Northern Blue Ridge and Ridge and Valley regions of west-central Virginia. It occurs in a narrow elevation range from 900-1170 m (3000-3840 feet). Sites are located on mesic to locally wet-mesic, lower slopes and terraces bordering small perennial streams and seeps in hollow-head concavities and ravines. Most sites for this community have a southerly aspect, and slopes are gentle. The overstory is dominated by Tsuga canadensis, with locally codominant Betula alleghaniensis and Quercus rubra. Acer rubrum, Betula lenta, Fagus grandifolia, Magnolia acuminata, Nyssa sylvatica, Prunus serotina, and Quercus alba are minor overstory and understory associates. Young Tsuga canadensis tends to dominate the lower tree layers. Rhododendron catawbiense dominates the shrub layer in moderately dense to very dense colonies. Ilex montana and Kalmia latifolia are constant, low-cover shrub associates. Few herbs occur in the type.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: Although the distribution of this community type on the Northern Blue Ridge is fairly well known, its status in the Ridge and Valley needs further investigation. The single known Ridge and Valley occurrence, in a high-elevation stream bottom on Warm Springs Mountain (Bath County), suggests that additional occurrences in this region are likely. However, like the distribution of ~Quercus montana / Rhododendron catawbiense - Kalmia latifolia Forest (CEGL008524)$$, the distribution of this unit appears to correspond to a geographic area in which Rhododendron maximum is spotty or absent. Throughout much of southwestern and west-central Virginia, as well as in the Southern Appalachians of North Carolina and Tennessee, habitats at all elevations favorable to Tsuga canadensis generally support extensive populations of Rhododendron maximum. Over most of this region, Rhododendron catawbiense is restricted to more xeric and/or exposed sites, and does not appear to be competitive with Rhododendron maximum in mesic habitats (A.S. Weakley pers. comm. 2001). On the Northern Blue Ridge and certain sites of the Ridge and Valley, where Rhododendron maximum is inexplicably rare, it is possible that the absence of Rhododendron maximum enables Rhododendron catawbiense to occur under a wider range of environmental conditions.

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available

Floristics: The overstory is dominated by Tsuga canadensis, with locally codominant Betula alleghaniensis and Quercus rubra. Acer rubrum, Betula lenta, Fagus grandifolia, Magnolia acuminata, Nyssa sylvatica, Prunus serotina, and Quercus alba are minor overstory and understory associates. Young Tsuga canadensis tends to dominate the lower tree layers. Rhododendron catawbiense dominates the shrub layer in moderately dense to very dense colonies. Ilex montana and Kalmia latifolia are constant, low-cover shrub associates. Few herbs occur in the type, none with >50% constancy in plots. The most characteristic species in the herb layer include Aralia nudicaulis, Clintonia umbellulata, Dennstaedtia punctilobula, Dryopteris intermedia, Maianthemum canadense, Medeola virginiana, and Oclemena acuminata (= Aster acuminatus). The delicate orchid Listera smallii occasionally grows in the dense shade and litter of Rhododendron catawbiense. With species richness ranging from 10 to 20 taxa per 400 m2 (mean = 16) in plot samples, examples of this vegetation can be considered floristically depauperate.

Dynamics:  The Tsuga canadensis component of Virginia stands has been devastated by outbreaks of hemlock woolly adelgid over the past several decades, leading to more open canopy conditions, along with increased regeneration and greater importance of Betula alleghaniensis and other hardwoods in most stands.
Environmental Description:  This community type occurs in a narrow elevation range from 900-1170 m (3000-3840 feet). Sites are located on mesic to locally wet-mesic, lower slopes and terraces bordering small perennial streams and seeps in hollow-head concavities and ravines. In contrast to the northerly aspects favored by ~Tsuga canadensis - Betula alleghaniensis - Acer saccharum / Dryopteris intermedia Forest (CEGL006109)$$, most sites for this community have a southerly aspect. Slopes are gentle (mean = 7° in plot samples) and usually concave in at least one direction. Soils have an extremely thick surface layer of root-rich, poorly decomposed duff and are extremely acidic (mean pH = 3.9), with very low base status.
Geographic Range: This community type is known only from seven locations in the Northern Blue Ridge and Ridge and Valley regions of west-central Virginia.

Nations: US

States/Provinces:  VA


Confidence Level: Moderate

Confidence Level Comments: No Data Available
Grank: G1?

Greasons: No Data Available
Type Name Database Code Classification Code
Class 1 Forest & Woodland Class C01 1
Subclass 1.B Temperate & Boreal Forest & Woodland Subclass S15 1.B
Formation 1.B.2 Cool Temperate Forest & Woodland Formation F008 1.B.2
Division 1.B.2.Na Eastern North American Forest & Woodland Division D008 1.B.2.Na
Macrogroup 1.B.2.Na.3 Appalachian-Interior-Northeastern Mesic Forest Macrogroup M883 1.B.2.Na.3
Group 1.B.2.Na.3.b Appalachian-Allegheny Northern Hardwood Forest G742 1.B.2.Na.3.b
Alliance A3302 Eastern Hemlock - Sweet Birch - Yellow Birch Forest Alliance A3302 1.B.2.Na.3.b
Association CEGL008513 Eastern Hemlock - Yellow Birch / Mountain Holly / Catawba Rosebay Forest CEGL008513 1.B.2.Na.3.b
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: ? Quercus rubra - Tsuga canadensis / Rhododendron catawbiense Association (Rawinski et al. 1996)
= Tsuga canadensis - (Betula alleghaniensis, Quercus rubra) / Ilex montana / Rhododendron catawbiense Forest (Fleming and Patterson 2009b)
= Tsuga canadensis - (Betula alleghaniensis, Quercus rubra) / Ilex montana / Rhododendron catawbiense Forest (Fleming and Patterson 2009a)
= Tsuga canadensis - (Betula alleghaniensis, Quercus rubra) / Ilex montana / Rhododendron catawbiense Forest (Fleming and Coulling 2001)
? Tsuga canadensis - Betula alleghaniensis / Rhododendron catawbiense / Dryopteris intermedia Association (Rawinski et al. 1996)
? Tsuga canadensis / Rhododendron catawbiense Forest (Coulling and Rawinski 1999)
< Eastern Hemlock: 23 (Eyre 1980) [pro parte.]
< Hemlock - Yellow Birch: 24 (Eyre 1980) [pro parte.]
Concept Author(s): G.P. Fleming and P. P. Coulling (2001)

Author of Description: G.P. Fleming

Acknowledgements: No Data Available

Version Date: 02-24-10
  • Coulling, P. P., and T. J. Rawinski. 1999. Classification of vegetation and ecological land units of the Piney River and Mt. Pleasant area, Pedlar Ranger District, George Washington and Jefferson National Forests, Virginia. Natural Heritage Technical Report 99-03, Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond.
  • Eastern Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boston, MA.
  • Eyre, F. H., editor. 1980. Forest cover types of the United States and Canada. Society of American Foresters, Washington, DC. 148 pp.
  • Fleming, G. P., K. D. Patterson, and K. Taverna. 2017. The natural communities of Virginia: A classification of ecological community groups and community types. Third approximation. Version 3.0. Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond, VA. [http://www.dcr.virginia.gov/natural-heritage/natural-communities/]
  • Fleming, G. P., and K. D. Patterson. 2009a. A vegetation classification for the Appalachian Trail: Virginia south to Georgia. Virginia Department of Conservation and Recreation, Division of Natural Heritage. In-house analysis, March 2009.
  • Fleming, G. P., and K. D. Patterson. 2009b. Classification of selected Virginia montane wetland groups. In-house analysis, December 2009. Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond.
  • Fleming, G. P., and P. P. Coulling. 2001. Ecological communities of the George Washington and Jefferson national forests, Virginia. Preliminary classification and description of vegetation types. Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond, VA. 317 pp.
  • Rawinski, T. J., K. N. Hickman, J. Waller-Eling, G. P. Fleming, C. S. Austin, S. D. Helmick, C. Huber, G. Kappesser, F. C. Huber, Jr., T. Bailey, and T. K. Collins. 1996. Plant communities and ecological land units of the Glenwood Ranger District, George Washington and Jefferson national forests, Virginia. Virginia Department of Conservation and Recreation, Division of Natural Heritage. Natural Heritage Technical Report 96-20. Richmond. 65 pp. plus appendices.
  • Rawinski, T. J., and T. F. Wieboldt. 1993. Classification and ecological interpretation of mafic glade vegetation on Buffalo Mountain, Floyd County, Virginia. Banisteria 2:3-10.