Physiognomy and Structure: No Data Available

Floristics: These forests are dominated by needle-leaved evergreen trees and have a characteristic understory of Southern Appalachian endemic species and a conspicuous bryophyte layer. Canopies are dominated by Picea rubens, with or without Abies fraseri, sometimes with lesser amounts of Betula alleghaniensis and Sorbus americana. The subcanopy contains canopy species as well as Acer spicatum and Amelanchier laevis. The shrub strata are dominated by deciduous species and can be sparse to dense. Typical shrub species include Viburnum lantanoides, Vaccinium erythrocarpum, Vaccinium simulatum, Sambucus racemosa var. racemosa (= Sambucus racemosa var. pubens), Rubus allegheniensis, Ilex montana, Rhododendron catawbiense, and Rubus canadensis. Extensive patches of Abies fraseri seedlings and standing dead stems of Abies fraseri are common. Herb density can be high but is inversely related to the density of the shrub layer. Common herbaceous species include Oxalis montana, Athyrium filix-femina ssp. asplenioides, Dryopteris campyloptera, and Clintonia borealis. Other herbs include Oclemena acuminata (= Aster acuminatus), Eurybia chlorolepis (= Aster chlorolepis), Carex gynandra, Carex pensylvanica, Chelone lyonii, Circaea alpina ssp. alpina, Houstonia serpyllifolia, Huperzia lucidula, Maianthemum canadense, Rugelia nudicaulis, Solidago glomerata, Streptopus lanceolatus var. roseus (= Streptopus roseus var. roseus), and Viola macloskeyi ssp. pallens. Bryophytes and lichens make up a considerable percent of the vegetative coverage in this community, occurring on the surface of the soil, trees, and fallen logs. Characteristic nonvascular species include Hylocomium splendens, Ptilium crista-castrensis, Leptodontium excelsum, Bazzania trilobata, Bazzania nudicaulis, Alectoria fallacina, Hypotrachyna virginica, Dicranum scoparium, and Dicranum fuscescens. Disjunct, outlier stands on summits in the Allegheny Mountains of West Virginia lack Abies and exhibit a dense canopy of Picea rubens, with a sparse to dense understory of Vaccinium erythrocarpum, on a luxuriant carpet of Bazzania trilobata and mosses. In Virginia, the rare plants Abies fraseri, Cardamine clematitis, and Prenanthes roanensis are minor components of this community.

Canopy structure and composition are fairly uniform, but understory composition changes continuously along a moisture gradient. Whittaker (1956) described five variations of the understory of Red Spruce - Fraser Fir Forests: (1) Valley subtype: moss, Oxalis, and low shrub cover <5%, high herb cover 30% and high shrub cover 20%; (2) North slopes and flats: moss and Oxalis cover 25-55%, low and high shrub cover 5-20%, high herb strata is dominated by Dryopteris with other mesic herbs; (3) Intermediate east- and west-facing slopes: moss, Oxalis and fern cover 15-30%, low and high shrub cover 5-10%; (4) South slope subtype: all five strata are <10% cover; and (5) Ridge and steep upper slope: rhododendron heath approaches full coverage of understory.

Dynamics:  Natural disturbances in this community include lightning fire, debris avalanches, wind disturbance, and ice storms (White and Pickett 1985, Nicholas and Zedaker 1989). The natural fire regime is estimated at longer than 500-1000 years. Stand-replacing fires may affect large-patch sizes but occur rarely, at 300- to 1000-year intervals; wind events are likely at more frequent intervals of 100 to 200 years (Gorman 2007). Human-initiated disturbances have included logging, slash fires, livestock grazing, and atmospheric pollutants. An exotic insect, the balsam woolly adelgid (Adelges piceae), invaded the Southern Appalachians in the late 1950s and has drastically altered the last undisturbed remnants of this community. This exotic pest kills mature Abies fraseri within seven years of infestation. In areas where mature Abies fraseri has been lost to woolly adelgid infestation, thickets of Rubus spp., Abies fraseri seedlings and saplings, Betula alleghaniensis, and Sorbus americana are dominant. Over time, Picea rubens, Betula alleghaniensis, Abies fraseri, Acer spicatum, and Sorbus americana increase in the tree layer, while Abies fraseri, Menziesia pilosa, Rubus idaeus ssp. strigosus, and Sambucus racemosa var. pubens increase in the shrub layer (White et al. 1993). Succession is especially slow after severe disturbance such as logging and slash fires. The most severely disturbed sites are predominately Prunus pensylvanica and Rubus spp. and may remain in a non-forested stage of succession for 60 years or more.