The tundra of the Smokies January 7, 2010Posted by Jenny in nature, Smoky Mountains, White Mountains.
Tags: boreal forest, geology, Mt. LeConte, Mt. Washington, treeline
This should probably be called “Taking an idea and running a little too far with it,” but it’s fun to speculate. I was reading a book called “A Roadside Guide to the Geology of the Smoky Mountains National Park” by Harry L. Moore.* He writes: “It is believed that approximately 20,000 to 16,500 years before the present, the mountain peaks of the Great Smoky Mountains region had tundra vegetation and had developed permafrost where the mean annual temperatures were below 32 degrees F.” [For comparison, the present mean annual temp on the summit of Mt. Washington is 27.2; in Gatlinburg, 56.6; summit of LeConte, approximately 45.] “In fact, a permanent snowpack may have persisted throughout the year in some higher hollows…. Alpine tundra herbs and subarctic shrubs persisted above 4,950 feet in elevation.” [About the same, or maybe a little higher than in the Whites at present.] “Boreal forests blanketed the hill slopes and valleys at lower elevations…. During the time between 16,500 and 12,500 years before the present, there was an increase in mean annual temperature and precipitation. Mass wasting and freeze-thaw action reworked sediments down the unstable mountain slopes. With warming climates, boreal forests spread into the middle elevations” [from the lower elevations; now found only at the crests of the Smokies] “and deciduous tree species (such as oak, birch, and ash) migrated into the valley, expanding from refuge areas in the coastal plain.”
* Harry L. Moore, “A Roadside Guide to the Geology of the Great Smoky Mountains,” Knoxville: University of Tennessee Press, 1988.