Name:
Abies fraseri - Picea rubens Forest Alliance
Reference:
Southeastern Ecology Working Gro...
Description:
This forest alliance is restricted to the highest mountain systems of the Southern Blue Ridge Province, in eastern Tennessee, western North Carolina, and southwestern Virginia, within the distributional range of Abies fraseri. Canopies can be dominated by Abies fraseri or Picea rubens, or codominated by Abies fraseri and 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 between 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. 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. Forests of this alliance occur on all topographic positions except the steepest rocky cliffs. Elevations range from 1370-2300 m (4500-6600 feet), with pure Abies fraseri associations best developed at 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 shallow and 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 acid 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 disturbance and lightning fire. Because of the shallow soils and extreme wind exposure, these forests are susceptible to large blowdowns, particularly in areas damaged by Adelges piceae, the Balsam Woolly Adelgid.
Accession Code:
VB.CC.19683.ABIESFRASERIPIC
Plot-observations of this Community Concept:
0
|
