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CEGL006620 Tsuga canadensis - Quercus rubra - Platanus occidentalis / Rhododendron maximum / Anemone quinquefolia Forest

The U.S. National
Vegetation Classification
Type Concept Sentence:
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Common (Translated Scientific) Name: Eastern Hemlock - Northern Red Oak - American Sycamore / Great Laurel / Wood Anemone Forest
Colloquial Name: Appalachian-Alleghenian Hemlock Floodplain Forest
Hierarchy Level: Association
Type Concept: This association is a mixed evergreen-deciduous floodplain forest, usually with a somewhat open canopy, with Tsuga canadensis prominent in the canopy and/or subcanopy. It occurs in small patches on higher floodplains of medium-sized streams which are infrequently flooded. Along smaller streams, stands may occur in positions subject to more frequent, low-energy floods. Mature stands along rivers may represent late-successional vegetation on stabilized terraces, but succession may be reversed by renewed scouring and bank erosion as rivers migrate across their floodplains. Microtopography is characterized by fluvial features including levees and swales. Codominant trees include Tsuga canadensis, Acer rubrum var. rubrum, Liriodendron tulipifera, and Quercus rubra. Mature stands have Tsuga canadensis codominant in the canopy layer, but younger stands may have dominance by this shade-tolerant species in the lower strata. Additional trees include Betula lenta, Fagus grandifolia, Fraxinus pennsylvanica, Robinia pseudoacacia, and Sassafras albidum. Tree species that characterize this association as a floodplain forest, including Platanus occidentalis and Betula nigra, usually occur at low cover. Shrub layers may have moderate to dense cover and are dominated by Rhododendron maximum. Herb layers are sparse and species-poor but usually include a few species more typical of floodplains than of upland hemlock forests, such as Amphicarpaea bracteata, Arisaema triphyllum, Cryptotaenia canadensis, and Rudbeckia laciniata.
Diagnostic Characteristics: No Data Available
Rationale for Nominal Species or Physiognomic Features:
Classification Comments: This association is classified based on data from 21 plots from the Bluestone, Buckhannon, Dry Fork, Gauley, Greenbrier, and Shavers Fork drainages in West Virginia. It is floristically similar to upland mixed deciduous-hemlock forests (e.g., Liriodendron tulipifera - Betula lenta - Tsuga canadensis / Rhododendron maximum Forest (CEGL007543)), but the presence of floodplain species and contrasting disturbance and successional dynamics support its recognition as a distinct association. Its potential range is larger than currently described, and data from other areas would help increase confidence in the type.
Similar NVC Types:
Tsuga canadensis - Liriodendron tulipifera - Platanus occidentalis / Rhododendron maximum - Xanthorhiza simplicissima Wet Forest, note:
Physiognomy and Structure: No Data Available
Floristics: This association is a mixed evergreen-deciduous floodplain forest, usually with a somewhat open canopy, codominated by Tsuga canadensis in the canopy and/or subcanopy. Trees along the river's edge often lean towards and eventually topple into the river as the banks are undercut. Codominant trees include Liriodendron tulipifera, Acer rubrum var. rubrum, and Quercus rubra. Mature stands have Tsuga canadensis codominant in the canopy layer, but younger stands may have dominance by this shade-tolerant species in the lower strata. Additional trees include Betula lenta, Fagus grandifolia, Fraxinus pennsylvanica, Oxydendrum arboreum, and Nyssa sylvatica. Tree species that characterize this association as a floodplain forest, including Platanus occidentalis, Betula nigra, and Liquidambar styraciflua, usually occur at low cover. Shrub layers may have moderate to dense cover. In some areas, the shrub layer is dominated by Rhododendron maximum and in some areas the short, rhizomatous shrub Xanthorhiza simplicissima may be abundant. Herb layers are sparse and species-poor but usually include a few species more typical of floodplains than of upland hemlock forests. Herbs include Anemone quinquefolia, Amphicarpaea bracteata, Arisaema triphyllum, Aristolochia macrophylla, Carex plantaginea, Conopholis americana, Cryptotaenia canadensis, Dryopteris intermedia, Eurybia divaricata, Galium triflorum, Maianthemum canadense, Maianthemum racemosum ssp. racemosum, Mitchella repens, Osmorhiza claytonii, Osmunda regalis var. spectabilis, Parthenocissus quinquefolia, Polygonatum pubescens, Polystichum acrostichoides, and Rudbeckia laciniata var. laciniata.
Dynamics: Mature stands along rivers may represent late-successional vegetation on stabilized terraces, but succession may be reversed by renewed scouring and bank erosion as rivers migrate across their floodplains. Trees along the river's edge often lean towards and eventually topple into the river as the banks are undercut.
Environmental Description: This association occurs in small patches on higher floodplains of medium-sized streams which are infrequently flooded. Along smaller streams, stands may occur in positions subject to more frequent, low-energy floods. Mature stands along rivers may represent late-successional vegetation on stabilized terraces, but succession may be reversed by renewed scouring and bank erosion as rivers migrate across their floodplains. Microtopography is characterized by fluvial features including levees and swales. In West Virginia, plot sampled stands of this association occur at elevations ranging from 207 to 632 m (675-2073 feet). Unvegetated ground cover is typically dominated by litter but may also include coarse woody debris (flotsam) and exposed sand and rock in more recently flooded examples. Soils are temporarily flooded, well-drained, deep, stone-free sand with a thin surficial duff layer, and test medium to extremely acidic.
Geographic Range: This association is currently known from floodplains of medium-sized streams west of the Eastern Continental Divide in West Virginia, including the Bluestone, Buckhannon, Dry Fork, Gauley, Greenbrier, and Shavers Fork rivers and their tributaries.
Nations: US
States/Provinces: WV
US Forest Service Ecoregions (1994/1995)
Domain Name:
Division Name:
Province Name: Central Appalachian Broadleaf Forest - Coniferous Forest - Meadow Province
Province Code: M221    Occurrence Status: Confident or certain
Section Name: Cumberland Mountains Section
Section Code: M221C     Occurrence Status: Confident or certain
US Forest Service Ecoregions (2007)
Domain Name:
Division Name:
Province Name: Central Appalachian Broadleaf Forest - Coniferous Forest - Meadow Province
Province Code: M221    Occurrence Status: Confident or certain
Section Name: Northern Cumberland Mountains Section
Section Code: M221C     Occurrence Status: Confident or certain
Omernik Ecoregions:
Confidence Level: Moderate
Confidence Level Comments:
Grank: GNR
Greasons: The area occupied by this association has probably been greatly decreased by conversion of upper floodplains for agriculture and other human uses from the late 1700s through the mid-1900s. Tsuga canadensis is currently threatened by the exotic insect hemlock woolly adelgid (Adelges tsugae). Many hemlocks are already dead in floodplains along the Greenbrier River, and this insect pest is known from the Bluestone River, while trees along the Shavers Fork still appear healthy. Along the Gauley River, occurrences of this association are impacted by camping associated with whitewater rafting. There are currently insufficient data to assign a numeric rank.
Concept Lineage:
Predecessors:
Obsolete Names:
Obsolete Parents:
Tsuga canadensis - Liriodendron tulipifera Forest Alliance
Synonomy: >< Tsuga canadensis - Betula nigra / Rhododendron woodland (Walton and Anderson 1997)
= Tsuga canadensis - Quercus rubra - (Betula nigra) / Rhododendron maximum Floodplain Forest [Hemlock Floodplain Forest] (Vanderhorst 2017a)
Concept Author(s): S. Gawler
Author of Description: S.C. Gawler and J. Vanderhorst
Acknowledgements:
Version Date: 20Dec2018
References:
  • Eastern Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boston, MA.
  • Perez, John. Personal communication. Biologist, USDI National Park Service, Glen Jean, WV.
  • Vanderhorst, J. 2017a. Wild vegetation of West Virginia: High floodplain forests and woodlands. West Virginia Division of Natural Resources, Natural Heritage Program. [http://wvdnr.gov/Wildlife/Factsheets/HighFloodplain.shtm]
  • 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.
  • Vanderhorst, J. P., B. P. Streets, Z. Arcaro, and S. C. Gawler. 2010. Vegetation classification and mapping at Gauley River National Recreation Area. Technical Report NPS/NER/NRTR--2010/148. National Park Service, Philadelphia, PA.
  • Walton, D., and M. Anderson. 1997. Critical habitats and associated communities in the riparian zone of the Gauley River. West Virginia Division of Natural Resources, Natural Heritage Program, Elkins.
  • WVNHP [West Virginia Natural Heritage Program]. No date. Unpublished data. West Virginia Natural Heritage Program, Elkins.