Climate Matters: Duller fall foliage as climate change stresses trees

Among the pumpkin spice and spooky decorations, the namesake of the fall season may be getting duller. The vibrant colors of fall foliage could be harder to see as an unstable climate stresses trees and keeps temperatures hotter for longer.

Historically leaves start to change in Missouri in late September, peaking about a month later in late October. But this can shift due to abnormal weather conditions around the fall season. As the climate warms, summer heat lasts longer, which delays the cooler fall temperatures that trigger trees to shed their leaves. On the other hand, drought can stress trees into changing color ahead of schedule, and drought is also becoming more of a problem in a changing climate.

Bob Rives, a forester with the Missouri Department of Conservation, says foliage forecasting is already complicated itself, and a complex changing climate adds to the challenge. He says temperature and sunlight have a more direct impact on fall foliage compared to rainfall.

Bob pointed out the 2012 extreme drought as an example as trees were vibrant and colorful with the extreme dry conditions. In other instances, Bob notes "When trees become very stressed they can just kind of go straight to brown, where we don't have a big window of nice, brilliant colors like we all like to see." Overall, Bob says local foliage is on schedule thanks to near-average rainfall for the first part of the year. Colors are already changing across the area and peak colors will be visible by later October.