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CEGL006209 Carya glabra - Quercus (rubra, montana) - Fraxinus americana / Viburnum rafinesqueanum Forest
Type Concept Sentence: No Data Available
Common (Translated Scientific) Name: Pignut Hickory - (Northern Red Oak, Chestnut Oak) - White Ash / Downy Arrow-wood Forest
Colloquial Name: Potomac River Bedrock Terrace Oak - Hickory Forest
Hierarchy Level: Association
Type Concept: This dry oak-hickory forest occurs on elevated bedrock terraces above the Potomac River for several miles below Great Falls. These level to gently sloping metamorphic bedrock terraces are 12-15 m (40-50 feet) above the river level and are subject to very rare (30- to 85-year) flood events. The community is a stunted open forest or woodland dominated by Carya glabra, Quercus alba, Quercus rubra, and Quercus montana occurring with Fraxinus americana. Other characteristic woody species include Juniperus virginiana, Ostrya virginiana, Chionanthus virginicus, Viburnum rafinesqueanum, Vaccinium stamineum, Vaccinium pallidum, and Ptelea trifoliata. The herbaceous layer is dense to moderately dense, species-rich, and usually dominated by grasses and sedges, especially Piptochaetium avenaceum, Danthonia spicata, and Carex albicans var. albicans. Spring ephemerals, such as Cardamine angustata, Erythronium americanum, Claytonia virginica, Corydalis flavula, and Phacelia dubia, are frequent, while lithophytes on and around rock outcrops include Arabis lyrata, Cardamine parviflora, Scutellaria saxatilis, and Asplenium platyneuron. The introduced invasive plants Microstegium vimineum, Vinca minor, Alliaria petiolata, and Lonicera japonica are problematic in most stands of the type. This community is distinguished by its unique environmental setting on ancient river terraces, its species composition indicative of high base substrate, and its high species richness, with values frequently ranging between 70 and 100 species per 400 m2.
Diagnostic Characteristics: No Data Available
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: This type is supported by quantitative analysis of 13 Maryland and 5 Virginia plots in a 1250-plot regional dataset assembled for the NCR parks vegetation mapping project.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available
Floristics: This community is an open forest of stunted (usually 15 m tall or less) trees. Carya glabra and several oaks (Quercus rubra, Quercus montana (= Quercus prinus), Quercus alba) and Fraxinus americana are codominant in the overstory. Quercus stellata, Pinus virginiana, Nyssa sylvatica, and Acer rubrum may be present at low cover. Juniperus virginiana and Ostrya virginiana are constant species at low cover in the understory. Chionanthus virginicus, Viburnum rafinesqueanum, Vaccinium stamineum, Vaccinium pallidum, Cornus florida, and Ptelea trifoliata are common shrubs. The herbaceous layer is dense to moderately dense, species-rich, and usually dominated by grasses (Piptochaetium avenaceum (= Stipa avenacea), Melica mutica, Dichanthelium boscii, Dichanthelium laxiflorum, Dichanthelium commutatum, Dichanthelium dichotomum, Danthonia spicata, Bromus pubescens, and Muhlenbergia tenuiflora), and sedges (Carex albicans var. albicans, Carex pensylvanica, Carex swanii, Carex umbellata, Carex nigromarginata, Carex willdenowii, Carex woodii, Carex planispicata, Carex retroflexa, and Trichophorum planifolium). Typical forbs include Arabis laevigata, Tipularia discolor, Liparis liliifolia, Oxalis violacea, Amphicarpaea bracteata, Solidago caesia, and the spring ephemerals Cardamine angustata (= Dentaria heterophylla), Erythronium americanum, Claytonia virginica, and Corydalis flavula. Phacelia dubia, Arabis lyrata, Cardamine parviflora, Scutellaria saxatilis, and Asplenium platyneuron are frequent on and around rock outcrops. The introduced invasive plants Microstegium vimineum, Vinca minor, Alliaria petiolata, and Lonicera japonica are problematic in most stands of the type. Mean species richness of 18 plot samples was 70 taxa per 400 m2 (range = 46 to 111 taxa).
Dynamics: Shallow, droughty soil over flat-lying bedrock appears to be the primary environmental factor driving the composition and physiognomy of this association. This habitat is subject to rare (every 30 to 85 years) catastrophic flood events which may remove soil, preventing deep soil accumulations.
Environmental Description: This dry oak-hickory forest occupies level to gently sloping bedrock terraces of metamorphic rocks (schists and metagraywacke, with intrusions of amphibolite) along the stretch of the Potomac River below Great Falls. These terraces are 12-15 m (40-50 feet) above the average river level. Exposed bedrock may comprise from 1 to 45% of the surface. Sites are subjected to rare (average return interval of 30 to 85 years) scouring floods (Lea 2000). These catastrophic flood events are thought to deposit sediments rich in shell fragments which contribute to the high soil base status. However, soil samples collected from 15 plots were, on average, strongly or extremely acidic (mean pH = 4.6), with moderately low calcium and total base saturation levels. A few plots had much higher pH or calcium values, perhaps indicative of a somewhat heterogeneous soil environment induced by interbedded acidic and mafic rocks. Overall, soils are shallow, seasonally droughty sandy loams, with some organic horizon development.
Geographic Range: This community occurs along the stretch of the Potomac River below Great Falls. It is found on both the Maryland and Virginia sides of the gorge.
Nations: US
States/Provinces: MD, VA
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.758559
Confidence Level: High
Confidence Level Comments: No Data Available
Grank: G1G2
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.2 Appalachian-Northeastern Oak - Hardwood - Pine Forest & Woodland Macrogroup | M502 | 1.B.2.Na.2 |
| Group | 1.B.2.Na.2.c White Oak - Chestnut Oak - Pignut Hickory Forest & Woodland Group | G650 | 1.B.2.Na.2.c |
| Alliance | A4436 White Oak - Pignut Hickory - White Ash Forest Alliance | A4436 | 1.B.2.Na.2.c |
| Association | CEGL006209 Pignut Hickory - (Northern Red Oak, Chestnut Oak) - White Ash / Downy Arrow-wood Forest | CEGL006209 | 1.B.2.Na.2.c |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: = Carya glabra - Quercus (alba, rubra, prinus) / Ostrya virginiana / Carex pensylvanica Forest (Fleming and Patterson 2003)
= Carya glabra - Quercus (rubra, prinus) - Fraxinus americana / Viburnum rafinesquianum / Piptochaetium avenaceum Forest (Fleming et al. 2007b)
= Carya glabra - Quercus (rubra, prinus, alba) / Ostrya virginiana / Panicum boscii Forest (Lea 2000)
= Quercus (prinus, rubra, alba) - Carya glabra / Ostrya virginiana Forest (Thomson et al. 1999)
= Carya glabra - Quercus (rubra, prinus) - Fraxinus americana / Viburnum rafinesquianum / Piptochaetium avenaceum Forest (Fleming et al. 2007b)
= Carya glabra - Quercus (rubra, prinus, alba) / Ostrya virginiana / Panicum boscii Forest (Lea 2000)
= Quercus (prinus, rubra, alba) - Carya glabra / Ostrya virginiana Forest (Thomson et al. 1999)
- Eastern Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boston, MA.
- Fleming, G. P. 2007. Ecological communities of the Potomac Gorge in Virginia: Composition, floristics, and environmental dynamics. Natural Heritage Technical Report 07-12. Unpublished report submitted to the National Park Service. Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond. 341 pp. plus appendices.
- 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., K. Taverna, and P. P. Coulling. 2007b. Vegetation classification for the National Capitol Region parks, eastern region. Regional (VA-MD-DC) analysis prepared for NatureServe and USGS-NPS Vegetation Mapping Program, March 2007. Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond.
- Fleming, G. P., and K. D. Patterson. 2003. Preliminary vegetation classification for the National Capitol Region parks. Regional (VA-WVA-MD-DC) analysis prepared for NatureServe and USGS-NPS Vegetation Mapping Program, March 2003. Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond.
- Fleming, Gary P. Personal communication. Ecologist, Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond, VA.
- 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.
- Lea, C. 2000. Plant communities of the Potomac Gorge and their relationship to fluvial factors. M.S. thesis, George Mason University. Fairfax, VA. 219 pp.
- Southworth, S., and D. Denenny. 2006. Geologic map of the national parks in the National Capital Region, Washington, D.C., Virginia, Maryland, and West Virginia: U.S. Geological Survey Open-File Report 2005-1331. [http://pubs.usgs.gov/of/2005/1331/]
- Thomson, D., A. M. Gould, and M. A. Berdine. 1999. Identification and protection of reference wetland natural communities in Maryland: Potomac watershed floodplain forests. The Biodiversity Program, Maryland Department of Natural Resources, Wildlife and Heritage Division. Annapolis. 119 pp.