The peak color season at Starved Rock and Matthiessen State Park is the second and fourth week of October.
Lisa Sons, the Natural Resource Coordinator with the Illinois Department of Natural Resources describes what you’re seeing:
Sunlight moving further away in the Northern Hemisphere means tree leaves receive a signal to stop producing the starches and sugars that keep them green all summer.
Among trees whose leaves explode in the Fall are Elm, Walnut, Ash, Silver and Sugar Maples and Quaking Aspen. All of these trees are native and common to local state parks.