Fall foliage, hoarfrost, and smoke, oh my!
This Thanksgiving, my family and I journeyed through part of the Southern Appalachians we frequent most often: the Great Smoky Mountains. It was like any other trip through the mountains this time of year, except we saw colorful leaves still hanging on to the trees in late November in the lower to mid-elevations (peak foliage in the area is usually late October).
As we rapidly gained altitude, we saw a chilling, yet breathtaking sight that contrasted the warm autumn foliage – hoarfrost…brrr! As we headed back home from Tennessee through North Carolina and Georgia, we happened upon several smoking forest fires, and it was plain eerie to say the least. Let's take a closer look at what this smoke is all about.
The Place of the Blue Smoke
The Cherokee call the Smokies “shaconage†in their native language, or “place of the blue smokeâ€. This mysterious blue haze is a natural phenomenon caused by a reaction driven by sunlight between volatile organic compounds emitted by trees as well as water vapor from transpiration-basically plant exhalation.
Unfortunately, air pollution from smog has greatly reduced visibility of mountain views and obscured the Smokies' trademark look, replacing it with a sort of whitish haze from smog formation. Smog forms when nitrogen oxides react with volatile organic compounds in the presence of sunlight. Sounds familiar doesn't it?
Speaking of smoke, black carbon aerosols from wildfire smoke also increase haziness dramatically. As we have seen in the past month, wildfires do much more than ruin the mountain aesthetic, for the better and for worse.
Wildfires have temporarily and drastically reduced visibility in many parts of the Southeast this fall- even reaching all the way to Atlanta. We even had smoky conditions in Athens that left the air and buildings smelling like one big campfire. One of the fires I saw firsthand in the Great Smoky Mountains National Park (GSMNP) was near a popular hiking trail named Chimney Tops… no pun intended. I wonder who started the fire? Cue the music.
Views of hazy (from wildfires/air pollution) and blue smoke
Are All Fires Bad?
From a human livelihood perspective, we do not want forests igniting, but we now understand that ecologically, not all forest fires are bad. They diversify the mosaic of plant communities in a landscape by opening up the forest and allowing sunlight to reach the forest floor, encouraging plant regeneration and certain wildlife species.
In fact, the Cherokee intentionally set fires to attract hunting game and to farm. In addition, fire is necessary for some plant species to germinate, like the table mountain pine. Animal species such as the red-cockaded woodpecker rely on fire as well because they require forest without a lot of overgrown brush. As with most situations, there will be winners and losers, and fires may be as regenerative as they are destructive.
High and Dry
An average of two lightning-ignited fires occur per year in the GSMNP, usually at lower to mid-elevations on dry slope. The recent drought has created unusually warm and dry conditions even at high elevations and is also lowering streamflow. Forests are more vulnerable to severe fires during droughts because standing vegetation, fallen woody debris, leaves, and even the soil and roots of plants become highly flammable kindling. As a result, there have been well over 150,000 acres of wildfire coverage throughout Appalachia.
Most recently, a severe fire in Gatlinburg, TN (one of the many), which is located right outside of the GSMNP, has damaged or destroyed over 1,500 structures and taken the lives of at least 14 people. A combination of heavy winds, abnormally dry climate, and you guessed it, embers from the Chimney Tops fire, caused the wildfire to grow from a little over an acre to 500 acres overnight and was recorded to be over 17,000 acres after spreading into Gatlinburg and others parts of Sevier County.
Thanks to modern satellite technology, meteorological expertise, dedicated firefighters and emergency response crews, the fires have been under careful monitoring, though some have already caused considerable damage despite best efforts to fight the fires. History was certainly made this November due to the worst drought in nearly a decade that has turned forests into kindling all over the Southeast. This will be a Thanksgiving that I will never forget. A lesson I learned from this unseasonable season is not to take water and fresh air for granted, nor my very life.
Suzie Henderson is an undergraduate student in the Odum School of Ecology at the University of Georgia. She is an amateur naturalist, experimental gardener, sporadic artist, and has a passion for our green planet and the crazy people who are a part of it. If this article sparked your interest or a question, connect with her on Facebook or suzieuga@uga.edu. More from Suzie Henderson.
