In which Moominmama learns to measure elevation in the Smoky Mountains by the smell of the trees... Hiking in the Great Smoky Mountains National Park, Moominmama knew she'd reached 6,000 feet of elevation whenever the woods started to smell like Christmas. That's because these mountains are home to the Fraser fir. The popular and fragrant Christmas tree is mostly grown on tree farms these days, but the Smokies are one of its rare natural habitats -- but only above a certain height. Clingmans Dome is the highest peak in the Smokies with a viewing tower at the top, overlooking a large stand of towering Fraser fir and providing 360-degree views of the ridge that divides Tennessee and North Carolina. To get there involves a long, winding road off Newfound Gap Road and then a short, steep hike up a paved path, because, of course, this is a big tourist spot. But there were other places where reaching the height to smell those trees required some serious leg work. One of Moo...