This year, according to Burdick, the wet weather in late spring and early summer created stress in some urban trees and along the edges of woodlands, so early color can be seen there. The true trigger though for full fall color though is the shorter days and longer nights.
"To get the best color we need that sap to thicken up so it needs to cool off a little bit so the tree can prepare, as the day shorten that's really the trigger that causes fall color to start," said Burdick.
The loss of sunlight causes a chemical breakdown in the leaf breaking down the green chlorophyll and allowing the reds, yellows, oranges and purples to show. Peak fall color is expected in the Miami Valley towards the end of the third full week of October.