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Image of George and Elizabeth Ellison by Quintin Ellison |
By George Ellison
There are a few basic concepts that have helped me through the years to sort out the almost bewildering diversity of the geologic aspects, plants, animals, and natural areas that make up these very old mountains we call home. The “Principle of Verticality” is a good example. It goes this way:
For every 1,000 feet gained in elevation, the mean temperature decreases about four degrees Fahrenheit. And every 1,000 feet gained in elevation is roughly equivalent to a change of 200–250 miles in latitude.
This means that, if you travel from the lowest elevations in the Southern Blue Ridge Province at about 1,500 feet to the higher elevations above 6,000 feet, it's the equivalent of traveling more than 1,000 miles northward in regard to the habitats you will encounter.
Many northern species find their southernmost range in North America at the highest elevations of Great Smoky Mountains National Park. Clingmans Dome illustration by Elizabeth Ellison. |
For instance, if you leave Bryson City, North Carolina, at a low-elevation pine-oak-hickory forest setting and travel to Clingmans Dome at 6,643 feet in the Great Smokies, you will arrive in a spruce-fir forest setting of the type you would only encounter many hundreds of miles to the north in lower elevations.
These factors have led me to think of the Southern Appalachians in general and the Southern Blue Ridge Province in particular as being peninsula-like extensions of northern habitat into the southeastern portion of the United States. This topography profoundly influences every aspect of the region's intertwined natural and human histories.
Living on the edge of the Smokies, George and Elizabeth Ellison were named “Blue Ridge Naturalists of the Year” in 2006. George was designated one of the “the 100 most influential people in the history of Great Smoky Mountains National Park” and, since 1987, he has written the Nature Journal column for the Asheville Citizen-Times. Elizabeth’s gallery is at 155 Main Street in Bryson City, North Carolina. Learn more online at elizabethellisongallery.com.