The firefighters are in remote areas fighting blazes that spread invisibly beneath 12 inches of sphagnum moss that blankets the ground.
``It's like mulch, and when it dries out it becomes tinder,'' Gary Chancey, a spokesman for the firefighters, told the Chattanooga Times Free Press.
Only faint streaks of smoke are visible at the surface while the acreage burns underneath, said Chancey, a Polk county native.
A dry season has been blamed for the 15 separate fires that are destroying about 3 million acres in Boundary, Alaska, U.S. Forest Service officials said.
About 3,000 firefighters from the U.S. Forest Service, Tennessee Valley Authority and other departments across the country have been rounded up for the Alaskan fire, said spokesman Terry McDonald.
Their main objective is to steer the flames away from populated areas, said Pete Buist, manager of the Alaska interagency units.
Another Tennessee firefighter, Jack McCarty of Cleveland, is managing a staging area in Alaska that's responsible for preparing equipment for about 1,000 firefighters during the blaze's peak.
``Jack has to have equipment readily available, and that means having a lot of moving parts,'' said Phil Musgrove, McCarty's supervisor.
Buist said so far 16 homes, two campers and 19 outbuildings have been destroyed by the fires.
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