CHAMPAIGN, lll. — The deep reds, crisp oranges and golden yellows that usually punctuate the fall landscape may not be so spectacular this year after a summer of statewide heat and drought.
“Drought is bad for fall colors,” said Jeffrey Dawson, a professor emeritus of natural resources and environmental sciences at Illinois. “In a normal fall season with plenty of rainfall, the leaves should begin to change in October. In a fall season such as this one, we are seeing a premature leaf drop. This affects fall colors because with leaves falling from the trees earlier, fewer leaves are left to actually change color.”
Even though the summer drought has affected the health of Illinois trees, state climatologist Jim Angel remains hopeful that fall colors will still be able to make an appearance this season.
“All is not lost – the recent rains and cooler weather have slowed the deterioration of the trees’ health. I’m a little more optimistic now than I was a month ago.
“Predicting fall color is still more art than science,” Angel added. “The best recipe for good fall color consists of a growing season without stress (such as that brought on by drought, flood, heat), followed by fall that has clear, sunny days and night temperatures that are crisp but not below freezing.
“You do not want a wet, stormy fall because the cloudy days and wet leaves cause the colors to be muted,” he said. “In addition, stormy weather has a habit of blowing the leaves off trees just as they turn color.”
Dawson said the color-change process is a living process.
“During the period of color change, sugars and other nutrients from the leaves move back into the tree, allowing it to retain (sugars and nutrients) efficiently, rather than shedding them with subsequent leaf fall.”
“For the first time since 1988, all of Illinois has experienced drought this year,” Angel said. “So the results are going to be similar around the state.”
Angel is affiliated with the State Water Survey, a unit of the Prairie Research Institute.For more information on the how color-change process works, visit the U. of I. Extension website.