One of the most spectacular sights in Tennessee is a forest in the middle of autumn. The previously green leaves adorning the many varieties of trees suddenly become engorged with color, and the resulting color spectrum can be breathtaking. At higher elevations throughout the state – particularly the Great Smoky Mountains – the change is even more drastic, and for around two weeks in the middle of October, the forest looks like it is on fire with the dramatic reds and oranges the trees proudly display.
What causes the color change?
Although certainly beautiful to look at, the changing colors also serve a very functional purpose for trees. As the days get shorter and shorter and the temperature begins to drop, the veins in the leaves will close off. This reduces the amount of chlorophyll (the chemical that makes plants green) that is present in each leaf.
Once the amount of chlorophyll drops, chemicals called carotenoids that were already present in the leaf start to take over and be revealed, giving the leaf its characteristic autumn color. Carotenoids are responsible for the yellow and orange tint in leaves of trees like hickories, ash, maple, birch, sycamore, and cottonwood.
Another chemical present in the leaves is anthocyanins. These are responsible for the red and purple coloring found in autumn leaves. Instead of being present in the leaf year-round like carotenoids, they are only produced in the late summer and early fall. Their production is related to the amount of phosphate in the leaf as well as the amount of sunlight the leaves receive. The more sunlight in the late summer and early autumn the tree receives (and the milder the temperatures), the bright its colors will be.
Anthocyanins are most commonly found in trees in the New England states, but they are present in trees throughout the country including oaks, maples, dogwoods, cherry trees, and sweetgums. The combination of anthocyanins and carotenoids are what give autumn forests their striking and often beautiful colors.
Best places to see autumn leaves in Tennessee
Without question, the most vivid colors occur in trees and forests in the highest elevations in the eastern part of the state, which is the Great Smoky Mountains National Park. At elevations around 4,500-6,000 feet, the leaves begin changing colors earlier, usually starting around mid to late September and peaking in the middle of October.
Clingman’s Dome, the highest point in Tennessee, and the Blue Ridge Parkway are both excellent vistas to view the leaves. The reason the colors in the Smokies is so intense is because of the sheer number and diversity of trees in the forest – in fact, there are over 100 species that are native to the area and almost all of them are deciduous.