Print Report

A0136 Picea rubens - Abies fraseri Forest Alliance

Type Concept Sentence: This vegetation is dominated by Abies fraseri and/or Picea rubens; Betula alleghaniensis and other northern hardwood species may be codominant in mixed stands. It is restricted to the highest mountain systems of the Southern Blue Ridge, in eastern Tennessee, western North Carolina, and southwestern Virginia, as well as with outliers in the Central Appalachians of West Virginia, primarily within the distributional range of Abies fraseri.

Common (Translated Scientific) Name: Red Spruce - Fraser Fir Forest Alliance

Colloquial Name: Southern Appalachian Spruce-Fir Forest

Hierarchy Level:  Alliance

Type Concept: Canopies can be dominated by Abies fraseri and/or Picea rubens; Betula alleghaniensis and other northern hardwood species may be codominant in mixed stands. Canopy/subcanopy species of minor importance can include Acer spicatum, Acer pensylvanicum, Amelanchier laevis, Betula alleghaniensis, Prunus pensylvanica, and Sorbus americana. Forests on extreme sites may have an open canopy, with stunted appearance and, in some communities, standing dead stems of Abies fraseri are common, with extensive patches of Abies fraseri seedlings in canopy gaps. The density and composition of the shrub and herbaceous strata vary among associations in this alliance. Forests in this alliance typically have a well-developed bryophyte layer. Mosses, liverworts, and lichens grow densely on fallen logs, tree trunks, and the forest floor, giving these forests a distinctive carpeted appearance. This alliance contains many species endemic to the Southern Blue Ridge or that have the bulk of their worldwide range in that region. This vegetation is restricted to the highest mountain systems of the Southern Blue Ridge, in eastern Tennessee, western North Carolina, and southwestern Virginia, as well as outliers in the Central Appalachians of West Virginia, primarily within the distributional range of Abies fraseri. These forests occur on all topographic positions except the steepest rocky cliffs. Elevations range from 1350-2300 m (4400-6600 feet), with pure Abies fraseri associations best developed above 1830 m (6000 feet). The dominant soils are Inceptisols with scattered occurrences of Spodosols at the highest elevations. Generally, soils can be described as rocky, with well-developed organic and A horizons. All soils in these high-elevation forests are low in base saturation, high in organic matter, and are acidic in reaction (pH 3-5), with a high aluminum content. The moisture regimes of these areas are mesic to wet due to high rainfall, abundant cloud cover, fog deposition, and low temperatures. The climate has been classified as perhumid, with the temperature varying elevationally from mesothermal to microthermal. The regional geology is dominated by complexly folded metamorphic, sedimentary, and igneous rocks of the Precambrian and early Paleozoic age, including phyllites, slates, schists, sandstones, quartzites, granites, and gneisses. These forests are affected by debris avalanches, wind and ice disturbance, and lightning fire. Because of the rocky soils and extreme wind exposure, these forests are susceptible to large blowdowns, particularly in areas damaged by the invasive balsam woolly adelgid (Adelges piceae).

Diagnostic Characteristics: These are spruce-fir forests of the Southern Appalachians characterized by the presence of Abies fraseri.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: The alliance is conceptually related to more northern spruce-fir alliances and shares many northern or boreal species (often occurring in communities of this alliance as disjuncts from their main distribution), but is considered a separate alliance because of its large component of Southern Appalachian endemic species. This alliance exists in good condition in only a small portion of its original range due to the impact of early 20th century, post-logging fires and the ongoing outbreak of the balsam woolly adelgid (Adelges piceae), an exotic pest that infests and kills mature Abies fraseri. Well-developed, undisturbed examples of this alliance are extremely rare. Present day Picea rubens and Abies fraseri vegetation in the Southern Appalachians is estimated to cover only 48% (69 square kilometers) of the presettlement area (Cogbill and White 1991). These forests may grade into forests dominated by northern hardwood species (Betula alleghaniensis, Fagus grandifolia, Acer saccharum) and may also occur adjacent to montane grasslands, high-elevation shrublands, or high-elevation rock outcrop communities. ~Picea rubens - (Betula alleghaniensis, Aesculus flava) / Rhododendron (maximum, catawbiense) Forest (CEGL004983)$$ is transitional to ~Picea rubens - Betula alleghaniensis - Aesculus flava Forest Alliance (A0138)$$, and is being placed there.

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: These are evergreen or mixed evergreen-deciduous forests and woodlands. Canopy height may be limited due to harsh climate conditions, including winds and ice damage. Many stands have lost coverage of Abies fraseri due to damage from the balsam woolly adelgid (Adelges piceae). Forests on extreme sites may have an open canopy, with stunted appearance and, in some communities, standing dead stems of Abies fraseri are common, with extensive patches of Abies fraseri seedlings in canopy gaps.

Floristics: Canopies of this vegetation can be dominated by Abies fraseri and/or Picea rubens. Canopy/subcanopy species of minor importance can include Acer spicatum, Acer pensylvanicum, Amelanchier laevis, Betula alleghaniensis, Prunus pensylvanica, and Sorbus americana. Forests on extreme sites may have a stunted appearance and, in some communities, standing dead stems of Abies fraseri are common, with extensive patches of Abies fraseri seedlings in canopy gaps. The density and composition of the shrub and herbaceous strata vary among associations in this alliance. Typical shrub species include Menziesia pilosa, Rhododendron carolinianum, Rhododendron maximum, Rhododendron catawbiense, Ribes rotundifolium, Rubus idaeus ssp. strigosus, Rubus allegheniensis, Sambucus racemosa var. racemosa (= Sambucus racemosa var. pubens), Vaccinium erythrocarpum, Vaccinium simulatum, Viburnum nudum var. cassinoides, and Viburnum lantanoides. Typical herbaceous species include Ageratina altissima var. roanensis, Angelica triquinata, Athyrium filix-femina ssp. asplenioides, Chelone lyonii, Circaea alpina ssp. alpina, Clintonia borealis, Dryopteris campyloptera, Eurybia chlorolepis (= Aster chlorolepis), Geum radiatum, Houstonia serpyllifolia, Huperzia lucidula, Medeola virginiana, Oclemena acuminata (= Aster acuminatus), Oxalis montana, Rugelia nudicaulis, Solidago glomerata, Streptopus lanceolatus var. roseus (= Streptopus roseus), and Viola macloskeyi ssp. pallens. Forests in this alliance typically have a well-developed bryophyte layer. Mosses, liverworts, and lichens grow densely on fallen logs, tree trunks, and the forest floor, giving these forests a distinctive carpeted appearance. Typical nonvascular species include Bazzania trilobata, Dicranum scoparium, Dicranum fuscescens, Hylocomiastrum umbratum, Hylocomium splendens, Hypnum spp., Polytrichum ohioense, Ptilium crista-castrensis, and Rhytidiadelphus triquetrus. This alliance contains many species endemic to the Southern Blue Ridge or that have the bulk of their worldwide range in that region. The alliance is conceptually related to more northern spruce-fir alliances and shares many northern or boreal species (often occurring in communities of this alliance as disjuncts from their main distribution), but is considered a separate alliance because of its large component of Southern Appalachian endemic species.

Dynamics:  These forests are affected by debris avalanches, wind and ice disturbance, and lightning fire. Because of the rocky soils and extreme wind exposure, these forests are susceptible to large blowdowns, particularly in areas damaged by the invasive balsam woolly adelgid (Adelges piceae).
Environmental Description:  These forests occur on all topographic positions except the steepest rocky cliffs. Elevations range from 1350-2300 m (4400-6600 feet), with pure Abies fraseri associations best developed above 1830 m (6000 feet). The dominant soils are Inceptisols with scattered occurrences of Spodosols at the highest elevations. Generally, soils can be described as rocky, with well-developed organic and A horizons. All soils in these high-elevation forests are low in base saturation, high in organic matter, and are acidic in reaction (pH 3-5), with a high aluminum content. The moisture regimes of these areas are mesic to wet due to high rainfall, abundant cloud cover, fog deposition, and low temperatures. The climate has been classified as perhumid, with the temperature varying elevationally from mesothermal to microthermal. The regional geology is dominated by complexly folded metamorphic, sedimentary, and igneous rocks of the Precambrian and early Paleozoic age, including phyllites, slates, schists, sandstones, quartzites, granites, and gneisses.
Geographic Range: This forest alliance is restricted to the highest mountain systems of the Southern Blue Ridge, in eastern Tennessee, western North Carolina, and southwestern Virginia, with disjunct northern outliers on the summits of West Virginia. With the exception of these disjunct occurrences in West Virginia, all are within the distributional range of Abies fraseri. Otherwise, these forests reach their northern range limit in southwestern Virginia, where they are confined to elevations above 1700 m (5400 feet) on Mount Rogers in Grayson and Smyth counties.

Nations: US

States/Provinces:  NC, TN, VA, WV


Confidence Level: Moderate

Confidence Level Comments: No Data Available
Grank: GNR

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.7 Sugar Maple - Yellow Birch - Eastern Hemlock Forest Macrogroup M014 1.B.2.Na.7
Group 1.B.2.Na.7.e Red Spruce - Fraser Fir - Yellow Birch Forest Group G632 1.B.2.Na.7.e
Alliance A0136 Red Spruce - Fraser Fir Forest Alliance A0136 1.B.2.Na.7.e
Association CEGL006049 Fraser Fir / Hobblebush / Mountain Woodfern - Mountain Woodsorrel / Splendid Feathermoss Forest CEGL006049 1.B.2.Na.7.e
Association CEGL006308 Fraser Fir / (Catawba Rosebay, Carolina Azalea) Forest CEGL006308 1.B.2.Na.7.e
Association CEGL007130 Red Spruce - (Fraser Fir) / (Catawba Rosebay, Great Laurel) Forest CEGL007130 1.B.2.Na.7.e
Association CEGL007131 Red Spruce - (Fraser Fir) / Southern Mountain Cranberry / Mountain Woodfern / Splendid Feathermoss Forest CEGL007131 1.B.2.Na.7.e
Concept Lineage: This alliance is equivalent to old A.136 (4/4).

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: > Abies fraseri Alliance (Grossman and Goodin 1995)
> Fraser Fir Forest (Whittaker 1956) [This Whittaker concept appears to be the pure fir stands.]
? Oligotrophic Forest (Rawinski 1992)
>< Red Spruce - Fraser Fir: 34 (Eyre 1980) [upland portions]
< Red Spruce Forest (Whittaker 1956) [This Whittaker concept appears to be mixed spruce-fir stands plus spruce-birch-hardwood.]
< Spruce-Fir Forests (White et al. 1993)
Concept Author(s): R.H. Whittaker (1956)

Author of Description: M. Pyne and L. Sneddon

Acknowledgements: We have incorporated significant descriptive information previously compiled by K.D. Patterson and L. Sneddon.

Version Date: 09-26-14
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