Print Report

CEGL006639 Tsuga canadensis - Acer saccharum - Fagus grandifolia / Dryopteris intermedia Forest

Type Concept Sentence: No Data Available

Common (Translated Scientific) Name: Eastern Hemlock - Sugar Maple - American Beech / Intermediate Woodfern Forest

Colloquial Name: Hemlock - Transitional Northern Hardwood Forest

Hierarchy Level:  Association

Type Concept: This association comprises hemlock - northern hardwood forests of the Allegheny Plateau, Lake Ontario and Lake Erie plains, Lower New England, and south to higher elevations of the Central Appalachian region. This forest is associated with cool, dry-mesic to mesic sites and acidic soils, often on rocky, north-facing slopes. Soils can have a thick, poorly decomposed duff layer over sandy loams. Tsuga canadensis is characteristic and usually dominant in the coniferous to mixed canopy. While hemlock generally forms at least 50% of the canopy, in some cases it may be as low as 25% relative dominance. Hardwood codominants include Acer saccharum and Fagus grandifolia (common), Betula alleghaniensis (uncommon), and Betula lenta, which may replace Betula alleghaniensis in some areas. Ostrya virginiana may be present as a small tree. Quercus spp. and Pinus strobus tend to be absent or, if present, only occur with low abundance. The shrub layer may be dense to fairly open and often includes Viburnum acerifolium and Acer pensylvanicum in addition to Tsuga canadensis regeneration. Herbs may be sparse, particularly in dense shade, but include Dryopteris intermedia, Medeola virginiana, Oxalis montana, Mitchella repens, Maianthemum canadense, Uvularia sessilifolia, Polystichum acrostichoides, Trientalis borealis, Huperzia lucidula, Eurybia divaricata, Oclemena acuminata, Dennstaedtia punctilobula, and Thelypteris noveboracensis. Nonvascular plants may be well-developed, often characterized by the liverwort Bazzania trilobata. Diagnostic characteristics of this forest are the dominance of Tsuga canadensis, presence of Acer saccharum and Fagus grandifolia, low abundance of either Betula alleghaniensis or Betula lenta, and a lack of abundant Quercus spp. or Pinus strobus. In Virginia stands, the most abundant trees are Tsuga canadensis, Betula alleghaniensis, Acer rubrum, and Quercus rubra; Fagus grandifolia and Acer saccharum are both inconstant and only occasionally important.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This type was formerly included in CEGL006109, which was split into CEGL006638 and CEGL006639. It was separated from ~Tsuga canadensis - Betula alleghaniensis - Acer saccharum / Dryopteris intermedia Forest (CEGL006638)$$ to better characterize the Allegheny Plateau - Lower New England and Central Appalachian characteristics. Many stands of this vegetation type in the national forests and Shenandoah National Park have been devastated during the past decade by adelgid-caused tree mortality. In some cases, 100% of the canopy hemlocks have been killed, littering the forest floor with downed wood and stimulating massive increases in understory growth, particularly of Betula spp. and Acer pensylvanicum. Since there is no practical treatment for the adelgid on a landscape level, one can only hope that natural pathogens will emerge to keep the adelgid in check before all of our examples of this community are severely degraded or lost. This type is nearly extinct in Virginia due to the almost complete loss of hemlock from adelgid outbreaks. Most of Virginia stands are now better classified as northern hardwoods of one type or another.

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

Floristics: Tsuga canadensis is dominant and forms at least 50% of the canopy, at least prior to impacts from the exotic insect pest hemlock woolly adelgid (Adelges tsugae). Fagus grandifolia and Acer saccharum are common and sometimes Betula alleghaniensis is uncommon or replaced by Betula lenta, and at the southern end of the range (in Virginia and Maryland), Liriodendron tulipifera may be an important overstory associate. The shrub layer may be dense to fairly open and often includes Viburnum acerifolium and Acer pensylvanicum in addition to Tsuga canadensis regeneration. Herbs may be sparse, particularly in dense shade, but often include Dryopteris intermedia, Medeola virginiana, Oxalis montana, Mitchella repens, Maianthemum canadense, Trientalis borealis, Huperzia lucidula (= Lycopodium lucidulum), Eurybia divaricata (= Aster divaricatus), and Thelypteris noveboracensis. Nonvascular plants may be well-developed, often characterized by the liverwort Bazzania trilobata. Diagnostic characteristics of this forest are the dominance of Tsuga canadensis, presence of Acer saccharum and Fagus grandifolia, low abundance of either Betula alleghaniensis or Betula lenta and a lack of abundant Quercus spp. or Pinus strobus. In Virginia stands, the most abundant trees are Tsuga canadensis, Betula alleghaniensis, Acer rubrum, and Quercus rubra; Fagus grandifolia and Acer saccharum are both inconstant and only occasionally important (G. P. Fleming, pers. comm.).

Dynamics:  Hemlock woolly adelgid (Adelges tsugae) is decimating hemlock stands in the eastern United States. Betula lenta is a common colonizer following the death of hemlocks.
Environmental Description:  This forest is associated with cool, dry-mesic to mesic sites and acidic soils, often on rocky, north-facing slopes. Soils can have a thick, poorly decomposed duff layer over sandy loams. In the southern part of the range, stands often occur in deep, sheltered ravines and along high-gradient mountain streams.
Geographic Range: This community is generally distributed in large patches from the Allegheny Plateau, Lake Ontario and Lake Erie plains, Lower New England and south to higher elevations of the Central Appalachian region in Maryland, West Virginia, and Virginia. In Virginia, it is restricted to the northwestern part of the state, where occurrences are rather local but sometimes extensive.

Nations: CA,US

States/Provinces:  CT, MA, MD, NJ, NY, ON, PA, RI, VA, WV


Confidence Level: Moderate

Confidence Level Comments: No Data Available
Grank: G3G4

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 CEGL006639 Eastern Hemlock - Sugar Maple - American Beech / Intermediate Woodfern Forest CEGL006639 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: > Betula alleghaniensis - Tsuga canadensis / Dryopteris intermedia - Huperzia lucidula Forest (Coulling and Rawinski 1999)
= Tsuga canadensis - Betula (alleghaniensis, lenta) / Dryopteris intermedia Forest (Fleming and Coulling 2001)
= Tsuga canadensis - Betula alleghaniensis - Acer saccharum / Dryopteris intermedia Forest (Fleming and Taverna 2006)
> Tsuga canadensis - Betula lenta - Betula alleghaniensis Association (Fleming and Moorhead 1996)
> Tsuga canadensis / Dryopteris intermedia / Bazzania trilobata Association (Rawinski et al. 1994)
? CNE dry transitional forest on sandy / gravelly soils (Rawinski 1984a)
< CNE mesic conifer [transition] forest on acidic bedrock/till (Rawinski 1984a)
< CNE mesic hardwood forest on acidic bedrock/till (Rawinski 1984a)
< Eastern Hemlock: 23 (Eyre 1980) [pro parte]
< Hemlock - Yellow Birch: 24 (Eyre 1980) [pro parte]
Concept Author(s): D. Faber-Langendoen

Author of Description: S.L. Neid, S.C. Gawler, G.P. Fleming and D. Faber-Langendoen

Acknowledgements: No Data Available

Version Date: 12-30-15
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