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G742 Appalachian-Allegheny Northern Hardwood Forest

Type Concept Sentence: This northern hardwood-conifer forest group occurs in the central and northeastern U.S., ranging from north-central New York and lower New England west to Lake Erie and south through the Central Appalachian region to the higher elevations of the Carolinas, on relatively cool, mesic sites.


Common (Translated Scientific) Name: Appalachian-Allegheny Northern Hardwood Forest

Colloquial Name: Appalachian-Northeast Mesic Forest

Hierarchy Level:  Group

Type Concept: This forest group occurs in the central and northeastern U.S., ranging from extreme southern Ontario, north-central New York and lower New England west to Lake Erie and south to the higher elevations of the Carolinas, on relatively cool, mesic sites. Northern hardwoods such as Acer rubrum, Acer saccharum, Betula alleghaniensis, Betula lenta, Fagus grandifolia, Fraxinus americana, Quercus rubra, and Tilia americana are characteristic, either forming a deciduous canopy or mixed with Tsuga canadensis (or in some cases Pinus strobus). Other common and sometimes dominant trees include Quercus spp. (most commonly Quercus rubra, but also Quercus alba, Quercus montana), Aesculus flava, Liriodendron tulipifera, and Prunus serotina. It is of more limited extent and more ecologically constrained in the southern part of its range, in higher elevations of the northern parts of Virginia and West Virginia. This type is one of the matrix forest types in the northern part of the Central Interior and Appalachian Division. In general, this group is dominated by long-lived, mesic species that form multi-layered uneven-aged forests. Canopy dynamics are dominated by single and multiple disturbances, encouraging gap phase regeneration. Larger disturbances include windthrow, insect attack and ice storms. Although stand-replacing wind events are rare, small to medium blowdown events are more common.

Diagnostic Characteristics: Typical northern hardwoods such as Acer saccharum, Betula lenta, Betula alleghaniensis, Fagus grandifolia, and Quercus rubra are characteristic, either forming a deciduous canopy or mixed with Tsuga canadensis (or in some cases Pinus strobus), but also containing one or more Appalachian species, including Aesculus flava, Liriodendron tulipifera, and Quercus montana. Notably absent from this group are the Laurentian-Acadian species of Picea rubens, Abies balsamea, and Betula papyrifera, and Thuja occidentalis is very localized.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: Northward this group is replaced by ~Laurentian-Acadian Hemlock - White Pine - Hardwood Forest Group (G741)$$ and ~Laurentian-Acadian Hardwood Forest Group (G743)$$, which are in a different macrogroup, but conceptually the groups may overlap on the Allegheny Plateau and in central New England. The presence of any one of Betula lenta, Liriodendron tulipifera, Quercus montana, and other Appalachian tree species (to be determined) are diagnostic. Other diagnostic shrub and herb species need to be identified as approximate indicators for the northern limit of this group''s range. Notably absent from this group are the Laurentian-Acadian species of Picea rubens, Abies balsamea, and Betula papyrifera, and Thuja occidentalis is very localized. This group may occur most typically at lower, warmer elevations in the High Allegheny Plateau region of northeastern Ohio, northern Pennsylvania and southern New York, as compared to G741 and G743. In the Central and Southern Appalachians, no distinction is made at the group level between hemlock-hardwood stands and hardwood stands, as hemlock is not as widespread, and stands are not as strongly hemlock-dominated as in the Laurentian-Acadian region (this pattern needs to be verified using USFS FIA tree plot data across G741, G742, and G743). The distinction is currently tracked at the alliance level. In the Southern Appalachian region, this type is restricted to higher elevations. There, at lower elevations it transitions to ~Appalachian-Central Interior Mesic Forest Group (G020)$$.

Similar NVC Types: No Data Available
note: No Data Available

Physiognomy and Structure: The canopy is characterized and often usually dominated by broad-leaved deciduous trees (northern hardwoods), but locally, stands may have a strong needle-leaved evergreen (conifer) component.

Floristics: The canopy is characterized and often usually dominated by northern hardwoods, such as Acer rubrum, Acer saccharum, Betula alleghaniensis, Betula lenta, Fagus grandifolia, Fraxinus americana, Quercus rubra, and Tilia americana, either forming a deciduous canopy or mixed with Tsuga canadensis or Pinus strobus. Tsuga canadensis can dominate the canopy on cool/moist sites at higher elevations and in shaded coves, valley bottoms and riparian areas. Rarely, Thuja occidentalis may be present. Bottomlands and toeslopes may also contain Fraxinus americana, as well as Platanus occidentalis (Whitney 1990). Other common associates may include Liriodendron tulipifera, Ostrya virginiana, Prunus serotina, Quercus alba, Quercus montana (= Quercus prinus), and Magnolia acuminata. The subcanopy and shrub layers are usually well-developed and may include Viburnum lantanoides (= Viburnum alnifolium), Viburnum acerifolium, Hamamelis virginiana, and Cornus alternifolia. Occasionally, Rhododendron maximum and sometimes Kalmia latifolia are present. Common herbaceous species include Maianthemum canadense, Onoclea sensibilis, Huperzia lucidula (= Lycopodium lucidulum), Dryopteris carthusiana (= Dryopteris spinulosa), Oxalis montana, and Mitchella repens (Lutz 1930, Braun 1950).

Dynamics:  In general, this group is dominated by long-lived, mesic species that form multi-layered uneven-aged forests. Canopy dynamics are dominated by single and multiple disturbances encouraging gap phase regeneration (Abrams and Orwig 1996). Larger disturbances include windthrow, insect attack and ice storms. Although stand-replacing wind events are rare, small to medium blowdown events are more common and occur at greater frequency on the plateau and exposed sideslopes (Ruffner and Abrams 2003). This group is currently being devastated in large parts of its range by the hemlock woolly adelgid (Adelges tsugae). This sucking insect is continuing to cause close to 100% mortality as it spreads from the north into the southern United States. The insect will most likely cause canopy hemlocks to be replaced by other canopy trees. Historically, this group was probably only subject to occasional fires. Fires that did occur may have been catastrophic and may have led to even-aged stands of pine and hemlock. Fire suppression appears to have increased the extent of this group at the expense of oak-pine systems.

Environmental Description:  Soil/substrate/hydrology: This group occurs predominantly on mesic sites over a broad range of topographic conditions, such as protected low and midslopes and valley bottoms, at elevations from 305 to 915 m (1000-3000 feet). Soils are usually neutral to acidic, and retain some moisture except during severe droughts. They are moderately well-drained to well-drained loamy or silty soils, and are rocky and usually deep in depressions among boulders. In riparian areas, stands are usually found along high-gradient (1-2%) streams. In the Central Appalachian center of its range, its ecological amplitude is somewhat broader, and it approaches matrix forest in some areas. At Shenandoah National Park, this group spans a broad range of environmental settings from steep west-facing slopes to south-facing gentle slopes.

Geographic Range: This group is found from central New England and north-central New York, south to higher elevations in North Carolina, and probably in adjacent eastern Kentucky.

Nations: CA,US

States/Provinces:  CT, GA, KY, MA, MD, ME, NC, NH, NJ, NY, OH, ON, PA, RI, SC?, TN, VA, VT, WV




Confidence Level: Moderate

Confidence Level Comments: No Data Available

Grank: GNR

Greasons: No Data Available


Concept Lineage: G163 split into 3 groups (G741, G742, G743)

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available

Synonomy: No Data Available

Concept Author(s): D. Faber-Langendoen, in Faber-Langendoen et al. (2012)

Author of Description: D. Faber-Langendoen, S.C. Gawler, R. White, R. Evans, M. Pyne

Acknowledgements: No Data Available

Version Date: 05-05-15

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