If it seems to you that fall colors are more erratic this year than usual, it’s not all in your head! The Great Lakes Echo feature by Juliana Moxley titled Last winter’s cold legacy: Fall colors slower to peak explains (in part) that last winter’s extreme cold is the culprit:
The harsh 2014 winter is partly to blame, said Bert Cregg, a professor in the department of horticulture at Michigan State University.
We are still having a good fall color season in Michigan, but we are likely to see some trees in full color while others are just beginning to turn, he said.
“As you’ll recall, last winter was extremely cold — one of the coldest winters on record,” Cregg said. “The winter stress delayed leaf-out for many trees, and then the tree’s timing was further delayed by a cold rather than normal spring.”
A warming climate can also affect fall color, said Howard Neufeld, a professor in the department of biology at Appalachian State University in North Carolina. Higher temperatures, altered timing and/or amounts of precipitation, changes in humidity, changes in cloud cover, increases in the length of the growing season and higher levels of nitrogen inputs in the ecosystem can all affect fall color variance.
“Increased precipitation means that light levels are most likely lower, and trees will do less photosynthesis,” Neufeld said. “With less photosynthesis, there are fewer sugars in the leaves. Warmer temperatures mean higher respiration rates, and more sugars will be metabolized.”
You can read on for lots more including an explanation of the scientific processes that impact color change.