Common (Translated Scientific) Name: Laurentian -Acidic Rocky Scrub & Grassland Macrogroup
Colloquial Name: Laurentian-Acadian Acidic Rocky Scrub & Grassland
Hierarchy Level: Macrogroup
Type Concept: This macrogroup comprises infertile scrub vegetation characterized by variable cover of shrubs, herbs, lichens, and occasional scattered trees, occurring on sandplains and rock outcrops in cool temperate regions of northeastern and north-central North America. Ericaceous shrubs or heath (Gaylussacia baccata, Kalmia angustifolia, Vaccinium angustifolium, Vaccinium myrtilloides, Vaccinium pallidum), scrub oaks (Quercus ilicifolia or Quercus prinoides), stunted oaks (Quercus rubra), and dwarf-shrubs (Arctostaphylos uva-ursi, Corema conradii, Gaultheria procumbens, Leiophyllum buxifolium, Pyxidanthera barbulata) characterize this vegetation throughout its range. Graminoids are mostly dominant in the herb layer and include Carex lucorum, Carex pensylvanica, Danthonia spicata, Deschampsia flexuosa, Schizachyrium scoparium, and/or the non-native Poa compressa. Pteridium aquilinum is a common fern. Nonvascular species are often important and may include mosses (e.g., Dicranum spp., Polytrichum spp.) and/or fruticose lichens (e.g., Cladonia spp.). Climate is north-temperate, continental to coastal. This vegetation develops in settings within this primarily forested region where exposed, dry, acidic, nutrient-poor conditions do not sustain forest vegetation.
Diagnostic Characteristics: Patchy, shrub-dominated vegetation of infertile, generally acidic substrates, including rock outcrops and sandplains (relatively flat to rolling sandy regions). Characteristic taxa are species of Vaccinium and other ericaceous shrubs or heath, Arctostaphylos uva-ursi, Corema conradii, Danthonia spicata, Juniperus communis, Quercus ilicifolia, Sibbaldiopsis tridentata, and in the New Jersey pine plains, dwarfed Leiophyllum buxifolium, Pinus rigida and Pyxidanthera barbulata.
Rationale for Nominal Species or Physiognomic Features:
Classification Comments: This macrogroup includes pine plains characterized by dwarfed Pinus rigida, restricted to the New Jersey Pine Barrens and Long Island, New York, as well as vegetation of serpentine rock in northern New England. The relationship of the latter to serpentine vegetation of the Gaspe Peninsula, Quebec, requires further analysis.
Similar NVC Types:
M502 Appalachian-Northeastern Oak - Hardwood - Pine Forest & Woodland, note: "has broadly similar herbaceous and shrub layers in woodland portions occurring on acidic, infertile substrates."
M506 Appalachian Rocky Felsic & Mafic Scrub & Grassland, note:
M509 Central Interior Acidic Scrub & Grassland, note:
Physiognomy and Structure: This vegetation may be shrub-, dwarf-shrub-, or herb-dominated, but is most often a patchwork of more than one physiognomy. Trees may be present, but are generally stunted in growth form (<2 m) and with low cover (<25%). Bare or lichen-encrusted rock may dominate large areas.
Floristics: Ericaceous shrubs or heath (Gaylussacia baccata, Kalmia angustifolia, Vaccinium angustifolium, Vaccinium myrtilloides, Vaccinium pallidum), scrub oaks (Quercus ilicifolia or Quercus prinoides), stunted oaks (Quercus rubra) and maples (Acer rubrum), and dwarf-shrubs (Arctostaphylos uva-ursi, Corema conradii, Gaultheria procumbens, Leiophyllum buxifolium, Pyxidanthera barbulata) characterize this vegetation throughout its range. Graminoids are mostly dominant in the herb layer and include Carex lucorum, Carex pensylvanica, Danthonia spicata, Deschampsia flexuosa, Schizachyrium scoparium, and/or the non-native Poa compressa. Pteridium aquilinum is a common fern. Comptonia peregrina is common in parts of the range. Nonvascular species are often important and may include mosses (e.g., Dicranum spp., Polytrichum spp.) and/or fruticose lichens (e.g., Cladonia spp.). When present, trees may include scattered individuals of Acer rubrum, Betula spp., Pinus spp., Prunus pensylvanica, Prunus serotina, Quercus spp., and other taxa that can colonize dry, open areas.
Dynamics: Exposure and occasional fire are the major factors keeping this vegetation relatively open on bedrock settings, while frequent fire is more typical in sandplains. Land-use history may be very important in creating or expanding thin soil on rock outcrops and in expanding pitch pine - scrub oak communities on sand (P. Swain pers. comm. 2014). Grazing by sheep on mountains has been considered to be a cause of soil loss and expansion of outcrop communities, similar to what has been reported on coastal New England sandplains (Motzkin and Foster 2002).
Environmental Description: Climate is north-temperate, continental to coastal. This vegetation develops in settings within this primarily forested region where exposed, dry, nutrient-poor conditions and fire do not easily sustain forest vegetation. Sand barrens examples can be common in regions with extensive sandplains, with relatively flat to rolling sandy soils. The substrate is rock or sand, with thin or localized areas of nutrient-poor soil. Substrate chemistry is usually acidic and nutrient-poor to (rarely) ultramafic. The substrate hydrology is largely very well- to excessively well-drained, except for small pockets within the expanses of rock that may accumulate runoff and precipitation.
Geographic Range: This macrogroup ranges across southeastern Canada from the Maritime Provinces to the Great Lakes, and south through the northeastern and upper midwestern U.S. to New Jersey, Pennsylvania, Ohio, and the mountains of Virginia and West Virginia.
Nations: CA, US
States/Provinces: CT, MA, ME, MI, MN, NB, NH, NS, NY, OH, ON, QC, VT, WI
|US Forest Service Ecoregions (2007)|
Northeastern Mixed Forest Province
Confident or certain
White Mountains Section
Confident or certain
Confidence Level: Low
Confidence Level Comments:
Synonomy: >< Dwarf Pine Plains (Whittaker 1979a)
> Heath (Latham et al. 1996)
> Heath-mat association type (Hill 1923)
> Pine-heath (Harshberger 1918)
> Plain Formation (Coremal) (Harshberger 1916)
> Rhodora (Latham et al. 1996)
> Rock Outcrop System, Northern Floristic Region (Minnesota DNR 2003)
> Scrub Oak Barrens (Latham et al. 1996)
> Southern Ontario Granite Barrens (Catling and Brownell 1999)
Concept Author(s): J.W. Harshberger (1916); A.F. Hill (1923); P.M. Catling and V.R. Brownell (1999)
Author of Description: S.C. Gawler and L. Sneddon
Version Date: 15Oct2014
- Catling, P. M., and V. R. Brownell. 1999. The flora and ecology of southern Ontario granite barrens. Pages 392-405 in: R. C. Anderson, J. S. Fralish, and J. M. Baskin, editors. Savanna, barren, and rock outcrops plant communities of North America. Cambridge University Press, Cambridge.
- Faber-Langendoen, D., J. Drake, S. Gawler, M. Hall, C. Josse, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, L. Sneddon, K. Schulz, J. Teague, M. Russo, K. Snow, and P. Comer, editors. 2010-2019a. Divisions, Macrogroups and Groups for the Revised U.S. National Vegetation Classification. NatureServe, Arlington, VA. plus appendices. [in preparation]
- Gawler, S. C., and A. Cutko. 2010. Natural landscapes of Maine: A classification of vegetated natural communities and ecosystems. Maine Natural Areas Program, Department of Conservation, Augusta.
- Harshberger, J. W. 1916. The vegetation of the New Jersey Pine Barrens. Reprinted 1970. Dover Publications, Inc., New York. 329 pp.
- Harshberger, J. W. 1918. American heaths and pine heaths. Memoirs of the Brooklyn Botanical Garden 1:175-186.
- Hill, A. F. 1923. The vegetation of the Penobscot Bay region, Maine. Proceedings of the Portland Society of Natural History 3:307-438.
- Latham, R. E., J. E. Thompson, S. A. Riley, and A. W. Wibiralske. 1996. The Pocono till barrens: Shrub savanna persisting on soils favoring forest. Bulletin of the Torrey Botanical Club 123:330-349.
- Minnesota DNR [Minnesota Department of Natural Resources]. 2003. Field guide to the native plant communities of Minnesota: The Laurentian Mixed Forest Province. Ecological Land Classification Program, Minnesota County Biological Survey, and Natural Heritage and Nongame Research Program. Minnesota Department of Natural Resources, St. Paul.
- Motzkin, G., and D. R. Foster. 2002. Grasslands, heathlands and shrublands in coastal New England: Historical interpretations and approaches to conservation. Journal of Biogeography 29:1569-1590. [http://harvardforest.fas.harvard.edu/sites/harvardforest.fas.harvard.edu/files/publications/pdfs/Motzkin_JBiogeography_2002_Grasslands.pdf]
- Motzkin, G., S. C. Ciccarello, and D. R. Foster. 2002. Frost pockets on a level sand plain: Does variation in microclimate help maintain persistent vegetation patterns? Journal of the Torrey Botanical Club 129:154-163.
- Swain, P. C., and J. B. Kearsley. 2011. Classification of the natural communities of Massachusetts. Version 1.4. Natural Heritage & Endangered Species Program, Massachusetts Division of Fisheries and Wildlife, Westborough, MA. [http://www.mass.gov/eea/agencies/dfg/dfw/natural-heritage/natural-communities/classification-of-natural-communities.html]
- Swain, Patricia. Personal communication. Natural Community Ecologist, Natural Heritage and Endangered Species Program, Massachusetts Division of Fisheries and Wildlife, Westborough, MA.
- Whittaker, R. H. 1979a. Appalachian balds and other North American heathlands. Pages 427-439 in: R. L. Specht, editor. Ecosystems of the world. Series Publication 9A. Heathlands and related shrublands: Descriptive studies. Elsevier Scientific Publishing Company, New York.
- Wiser, S. K. 1998. Comparison of Southern Appalachian high-elevation outcrop plant communities with their Northern Appalachian counterparts. Journal of Biogeography 25(3):501-513.