page_title: Southern Appalachian spruce–fir forest
section_title: Flora
hierarchical_section_title: Southern Appalachian spruce–fir forest / Ecology / Flora
caption_attribution_description: English: Spruce-fir forest near Mount Sterling on the Baxter Creek Trail in Great Smoky Mountains National Park
context_page_description: The southern Appalachian spruce–fir forest is an ecoregion of the temperate coniferous forests biome, a type of montane coniferous forest that grows in the highest elevations in the southern Appalachian Mountains of the eastern United States.
  The southern Appalachian spruce–fir forest is the highest and coldest forest type in the Appalachian range, thriving in elevations above 5,500 feet where the climate is too harsh to support the broad-leaved hardwood forest that dominates the region's lower elevations. A relict of the last Ice Age, this forest type covers just over 100 square miles, and is considered the second-most endangered ecosystem in the United States.
  Southern spruce–fir stands consist primarily of two needle-leaved evergreen species—the red spruce and the Fraser fir, nicknamed the "he-balsam" and "she-balsam," respectively. Regional entities sometimes refer to the southern spruce–fir forest as the "Canadian" or "boreal" forest due to its resemblance to the boreal forest of Canada.
context_section_description: 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.  Red spruce occurs as low as 3,500 feet (1,100 m) and normally becomes the dominant tree type at 5,500 feet (1,700 m).  Fraser fir appears at 5,500 feet, and becomes the dominant tree type at 6,200 feet (1,900 m).  The two trees can be distinguished by their needles and cones, with Fraser firs having blunt-shaped needles and upright cones and red spruces having prickly four-cornered needles and cones pointing downward.  The oldest red spruces are over 300 years old, and the tallest grow to over 100 feet (30 m).  The spruce–fir needles, when shed, can take up to ten years to decompose, and create a relatively acidic humus layer known as "mor."
  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.  A typical southern spruce–fir understory is home to shrubs such as Catawba rhododendron, thornless blackberry, mountain cranberry, and witch-hobble.  The spruce–fir herbaceous layer contains ferns such as the mountain wood fern, northern lady fern, and clubmoss, and over 280 species of mosses.  Wildflowers include Canada mayflower, blue-bead lily, and mountain wood-sorrel.  The Rugels ragwort is found only in the spruce–fir forest of the Great Smoky Mountains, and is one of eight plant species endemic to the southern Appalachian spruce–fir ecosystem.
caption: Mosses dominate the spruce–fir understory near the summit of Mount Sterling in the Great Smoky Mountains.
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