Appalachian temperate rainforest

In order to be defined as a rainforest, the forest must average at least 140cm (55in) of precipitation annually and a temperate rainforest as opposed to a tropical rainforest is defined by a mean annual temperature between 4 and 12 degrees Celsius (39 and 54 degrees Fahrenheit). Some sources however say even at least 50 inches of precipitation annually qualifies an area as being a rainforest. On the other hand, the book Temperate and Boreal Rainforests of the World states that a temperate rainforest is defined by least 1,200mm (47.24 inches) of average annual precipitation. And it must also be dense and lush with a rich understory and epiphytes. == Climate ==

The Appalachian temperate rainforest has a cool and mild climate and meets the criteria of temperate rainforests identified by forest ecologist Paul Alaback. Temperature and precipitation are extremely variable with elevation, with rainforest conditions usually but not always concentrated around spruce–fir forests at higher elevations. High altitudes hosting spruce–fir forest receive more than 2,000 millimeters (79in) of precipitation while large swaths of lower elevation rainforest receive more than 1,525 millimeters (60in). Winter and spring months see a gradient precipitation pattern, with higher rainfall concentrated in the south. Weak upslope air flow in summer brings more precipitation to the highest elevations, while autumn is typically driest with occasional intense rainfall from tropical systems. , sometimes called a cloud forest. In addition to the increased precipitation from orographic lift, cloud cover keeps the rate of water loss low due to minimal evapotranspiration. High elevation forests are immersed in clouds on 65% of growth-season days, leading some sources to describe the temperate rainforest as a cloud forest. Water intercepted from clouds accounts for 25% to 50% of annual precipitation, which is a high rate. For comparison, in the boreal rainforests of Eastern Canada, fog contributes only 5 to 8% of annual precipitation. According to a tentative classification advocated by DellaSala, Alaback, Spribille, Wehrden, and Nauman in 2011, high-elevation temperate rainforest regions in Central Appalachia could be interpreted as "a southerly extension of Appalachian boreal rainforests from Eastern Canada", although this interpretation requires further study. ==Locations==

The locations that are part of the Appalachian temperate rainforest include western North Carolina and eastern Tennessee. In western North Carolina, the rainforest includes Pisgah National Forest, Nantahala National Forest, Gorges State Park, DuPont State Forest, Chatahoochee-Oconee National Forest, and elsewhere in the Blue Ridge Mountains. The Great Smoky Mountains National Park which cover parts of North Carolina and Tennessee, are also part of the rainforest. The Appalachian temperate rainforest also includes the mountains in Northern Georgia such as Chattahoochee–Oconee National Forest, southwestern Virginia, northwestern South Carolina, and southeastern Kentucky. The absolute wettest location within the Appalachian temperate rainforest is Nantahala National Forest with some areas that average more than 100 inches of precipitation annually making one of the wettest locations in the continental US after the Pacific Northwest region. == Ecology ==

High precipitation levels, moderate year-round temperatures, and diverse terrain enable a wide range of species to survive. Flora spruce and fir forests dominate the cooler and wetter mountaintops while lighter deciduous trees are prevalent at lower elevations, a common pattern across the entire rainforest. Red spruce and Fraser fir are dominant canopy trees in high mountain areas. In higher elevations (over 1,980 meters or 6,500 feet), Fraser fir is dominant; in middle elevations (1,675 to 1,890 meters or 5,495 to 6,201 feet) red spruce and Fraser fir grow together; and in lower elevation (1,370 to 1,650 meters or 4,490 to 5,410 feet) red spruce is dominant. Below the spruce–fir forest, at around 1,200 meters (3,900ft), forest composition shifts in favor of deciduous trees such as American beech, maple, birch, and oak. Eastern skunk cabbage and common juniper are northern species that remained in this region after glaciers retreated. In addition to over 100 species of native trees, 1,400 other flowering plants and 500 moss and fern species live in the rainforest habitat. The rainforest's high humidity supports epiphytic plant species at greater height and diversity than elsewhere in the eastern United States. A wide range of mosses, ferns, and liverworts have been identified as high as above the forest floor. Lianas are also prevalent, especially in deciduous forest, with Virginia creeper, poison ivy, and various grapevines being the most common. Many species of salamander in this area do not have lungs, and breathe through their skin instead, so the wet environment of rotten trees and moist leaves is conducive for their survival. Many large species once lived in the area, but were extirpated by land-use and hunting changes brought about by European colonization. These include bison, elk, mountain lion, gray wolf, red wolf, fisher, river otter, peregrine falcon, and several species of fish. ==History==

during the Last Ice Age. The Appalachian Mountains began to form 460 million years ago with the collision of tectonic plates, and finished their uplift around 230 million years ago. However, evidence for residential activities in the highlands are absent prior to about 7,500 BCE, though the archaeological record does indicate hunting, flintworking, butchering, hideworking, and woodworking in the region. During this period, bounties on predators drove them to near-extinction, bison and elk were extirpated, and trapping decimated fur-yielding species. However, about 9,000 members of the tribe continue to live inside the Qualla Boundary, which lies within the rainforest biome. Encouraged by these factors and the Appalachian National Park Association (founded in 1899), Congress passed the Weeks Act in 1911 to enable the purchase of Federal lands in the Eastern United States. ==Threats==

Fire , Tennessee. Wildfires are a natural ecological process that has occurred within the Southern Appalachian temperate rainforest for millennia and plays an important role in the Southern Appalachian temperate rainforest ecosystem. However, fire suppression instituted after European colonization has created two significant issues in the region: a higher risk of "catastrophic wildfires", and declines in the abundance of disturbance-dependent species like Table Mountain pine and woodpeckers. After the 2016 Great Smoky Mountains wildfires, the National Park Service put increased effort into controlled burns "to invigorate a species or ecosystem that benefits from fire" and "reduce heavy accumulations of dead wood and brush which under drought conditions could produce catastrophic wildfires that threaten human life and valuable property." This is primarily due to pollutants from cars and coal plants settling in Appalachian valleys, trapped by the high mountain ridges. This deposition often has a pH below 4.0 and sometimes below 3.0, having significant impacts on tree cation concentrations, potentially leading to dangerous nutrient deficiencies. However, it has been hypothesized that higher elevations may be more resistant to climactic change. Originally a fungal pathogen introduced from Asia, the blight quickly spread, wiping out vast populations of mature chestnuts and dramatically altering the composition of forests across the Eastern US. Fir mortality in Appalachia rose by 1,600% by 1970, eventually killing two-thirds of adult trees. Initial efforts to control the adelgid largely failed, complicating repopulation efforts. Though there are signs of recovery in recent years—such as Kuwohi having three times more adult trees in 2020 than in the 1980s—these threats to the forest are not independent and scientists warn climate change may lead to another adelgid outbreak. Kristine Johnson, supervisory forester at the Great Smoky Mountains National Park, has suggested that warm winters and dry summers could support a resurgence of balsam woolly adelgid outbreaks. ==See also==