Southern Appalachian spruce–fir forest
[7] The largest southern spruce–fir stand is located in the higher elevations of the Great Smoky Mountains on the Tennessee-North Carolina border, stretching from roughly Kuwohi in the west to Mount Guyot in the east.
[5] Smaller pockets of spruce forest have been identified in the higher elevations of West Virginia, although these are devoid of Fraser firs and are typically considered disjunct from the highland spruce–fir community.
Being atop mountain summits or ridgecrests, southern spruce–fir forests are often subjected to hurricane-force winds, the strongest of which have been recorded at 175 miles (282 km) per hour.
Red spruce and Fraser fir survive at the highest elevations in southern Appalachia due to their ability to bear climatic conditions that are too extreme for most broad-leaved trees.
Both have conical shapes and flexible branches that make it less likely they will collapse under the weight of heavy snowfall, and both have a fatty substance in their needles that protects them from extreme cold.
"[4] Some northern hardwoods manage to survive amidst the spruce–fir ecosystem, namely yellow birch, American mountain ash, and pin cherry, the latter being especially common in areas damaged by fire.
Rogers at the northern end in Virginia; Breakneck and Pullback on Clingman's Dome in Tennessee; Burton and Craggey on Mount Mitchell in North Carolina.
[9][10][11][12][13][14] While the expanding glaciers of the Last Glacial Period did not reach as far as the southern Appalachians, the climatic shifts which resulted in their development brought lower temperatures to the region.
An alpine zone—where the climate is too harsh for any trees to survive—existed in the southern Appalachians at approximately 4,950 feet (1,510 m), leaving the region's highest elevations coated with tundra vegetation and permafrost.
[15] Botanists such as John Bartram and André Michaux began making excursions into the diverse southern Appalachian forests as early as the late 18th century.
[17] The general inaccessibility of the southern Appalachian highlands left the spruce–fir forests largely undisturbed for most of the 19th century, with the exception of Mount Mitchell and Roan Mountain, which became seasonal resort sites for tourists seeking an escape from hot summer temperatures.
[4][5] While the Great Smokies' spruce–fir zones were largely spared (with the exception of some logging around Mount Collins)[4] due to a restraining order on logging in 1926 that preceded the creation of Great Smoky Mountains National Park,[18] nearly half the virgin spruce elsewhere in the southern Blue Ridge Mountains was either cut or destroyed by logging-related fires.
[4] This rapid devastation led to numerous conservation movements, including one spearheaded by North Carolina Governor Locke Craig that culminated in the creation of Mount Mitchell State Park in 1915.
The red spruce, likewise, which is easily damaged by high winds, depends on the sturdier Fraser firs for protection in the wind-blasted higher elevations.
Air pollution and acid rain are also believed to be stunting the growth of red spruces (especially since the spruce–fir zones are often immersed in clouds), although to what extent is debatable.
[5] Anthropogenic factors, such as global warming and air pollution, are difficult to separate from natural causes in regional dieoffs of red spruce in the northeast and declining growth in the south.
