With autumn set to start Sept. 23, leaf peepers won’t have long to wait for forest leaves to turn and produce spectacular color displays. The vistas to be found in Southwest Virginia are just about guaranteed to be jaw-dropping regardless of the upcoming weather.

“We have such a great range of species which helps buffer us from weather effects,” said John Seiler, a Virginia Tech forestry professor and expert in tree physiology. “Red colors come from blackgum, scarlet oak, northern red oak, sassafras, red maple, sourwood, and white oak. Hickory, chestnut oak, red maple add yellow. So does yellow-poplar, which is dropping a bit early already. Sugar maple leaves turn yellow or red-orange. Black oak leaves bring golden brown.”

Seiler shares his expertise about the best times for viewing and how they will and won’t be affected by weather.

Q: When should people plan their trips to see the most spectacular fall colors?

“The best viewing period is generally always around the end of October. This year, I would suggest from Oct. 28 to Nov. 5. I always try to include two weekends for people to plan their fall foliage driving tours.”

Q: Could any weather factors affect that schedule?

“A lot also depends on the weather we get in September and early October. Good moisture and cooler temperatures are the ticket. As it has been getting a bit dry lately, I’ve been thinking it may move the season up some and shorten it, causing some trees to drop their leaves earlier. However, there is still time for more rain.”

Q: What triggers leaves to turn color, anyway?

“The main driver is shortening daylengths.  Seedlings which stay warm in a greenhouse but are exposed to short fall days still change color.  Day length does get modified by drought, which can cause trees to turn early, and lack of cool nights, which will cause them to turn a bit later in the year.”

Q: Does climate change have any effect on that schedule?

“Global warming in general will have only a very slight impact on fall color change. There is some research showing leaf changes occurring earlier but lasting longer. However, the overall effect is not significant enough for the weekend leaf peeper to notice a difference.”

About John Seiler
Seiler specializes in environmental stress effects on woody plant physiology, including water and pollutant stresses. He is quoted regularly in broadcast and print publications due to his expertise in tree physiology. Seiler is the Honorable and Mrs. Shelton H. Short Professor of Forestry at Virginia Tech and was named an Alumni Distinguished Professor in recognition of his extraordinary academic citizenship and distinguished service within the Virginia Tech community. Seiler teaches in the College of Natural Resources and Environment.  

Schedule an interview     
To schedule an interview, contact Mike Allen in the media relations office at mike.allen@vt.edu or 540.400.1700.



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