GATLINBURG, Tenn. (WATE) — With temperatures cooling down, it is beginning to feel a bit more like fall in East Tennessee and trees are beginning to change colors.
While the most exciting part of fall can be debated for hours, from pumpkin spice lattes and sweaters to football, one part of fall is enjoyed pretty much unanimously loved: fall foliage.
Those excited for fall in the Smokies can expect the vibrant transition in the coming weeks.
Biodiversity is a part of why the fall colors are so great in the Great Smoky Mountains National Park. There are at least 100 species of native trees in the Smokies, according to the National Park Service (NPS), and most of those shed their leaves yearly.
As for the earlier change in foliage in the mountain goes, it may be associated with the cooler weather that is prevalent at higher elevations. ThoughtCo.com published in 2017 that lapse rate, the relationship between elevation and temperature, is responsible for this change, with a temperature change of 5.4°F for an elevation increase of 1000 feet on a clear day.
The NPS suggests scenic drives through Clingmans Dome Road, the Blue Ridge Parkway, or the Foothills Parkway to enjoy the higher elevation fall foliage. NPS says hikers might also consider the Appalachian Trail, Inspiration Point on Alum Cave Trail, Oconaluftee River Trail, Look Rock Tower, and Sutton Ridge Overlook. Other considerations might include Clingmans Dome or visiting one of the many waterfalls in the GSMNP.
In the Smoky Mountains, fall colors are typically at peak:
- Mountain tops: near late September to early October
- Foothills: mid-to-late October
- Tennessee Valley: late October to beginning of November
Have you ever wondered why the leaves change at different times for different places? Or why the trees just seem brighter everywhere else? The science behind fall foliage is fascinating!
For the best fall foliage, guidance from the Smithsonian says that the best colors are produced when the weather is dry, sunny, and cool. The State University of New York ‘s College of Environmental Science and Forestry (SUNY ESF) agrees with this statement and offers further explanation.
“Temperature, light, and water supply have an influence on the degree and the duration of fall color. Low temperatures above freezing will favor anthocyanin formation producing bright reds in maples. However, early frost will weaken the brilliant red color. Rainy and/or overcast days tend to increase the intensity of fall colors. The best time to enjoy the autumn color would be on a clear, dry, and cool (not freezing) day.” SUNY ESF says.
Each of the colors seen is created by a variety of pigments in the leaves. Yellows and oranges are created by carotenoids while anthocyanins are responsible for reds and sometimes even purples according to the NPS. It seems to be common knowledge that the when the weather gets colder, the leaves change, but this change is actually kicked off by a break down of chlorophyll according to the Smithsonian Science Education Center (SSEC.) They explain that the fewer hours of sunlight, which results in cooler weather, is what causes the break down of the leaves’ chlorophyll. Since the chlorophyll that converts sunlight to food in most plants is what causes leaves to appear green, when it breaks down, the other pigments of the leaves shine through, granting the visions of yellow and orange created by carotenoids, and sometimes red.
The darker red colors can cause some questions by that logic, since red and green seem to be opposite colors. Fret not, SSEC has answers for the deeper fall colors as well. darker reds are caused by a chemical change within the leaf that goes deeper than the break down of chlorophyll. For trees with red leaves, sugars get trapped within the leaves and produce a new pigment that was not there before, SSEC said. The new pigments are called anthocyanins, which can range in color, but in tree’s typically produce red and sometimes purple pigments.
