GRAND RAPIDS, Mich. (WXMI) — Fall officially kicks off Thursday, bringing on all our fall favorites and gorgeous colors around Michigan, but how and why do the trees change colors?
The leaf’s color changes all have to do with our weather. Thursday is officially called the fall equinox, meaning when the sun is directly above the equator giving equal parts to both day and night. It’s the length of our nights that’s the leading cause of color change along with leaf pigment and weather.
Gorgeous colors fill our tree lines every year as fall rolls around and the weather starts changing. The shorter days and longer nights declines the intensity and amount of sunlight leaves receive. This in turn slowly closes off the cells at the base of each leaf and cuts off the plants food supply.
This is when we start to see the colors change on the leaves. Each leaf has as a color palette filled with different pigments. A leaf has three types of pigment called carotenoids, anthocyanin and chlorophyll. During the growing season leaves are green from the chlorophyll, but when photosyntheses continues to stop the chlorophyll is destroyed. This then makes way for the carotenoids and anthocyanin to shine through giving way to the yellow, orange, and red colors we love to see every fall.
How vibrant the fall colors are changes from year to year depending on the weather conditions before and during the process of the chlorophyll starting to die. A series of warm, sunny days and cool crisp but not freezing nights will bring the best colors. Soil moisture plays a role in the colors as well. If we have a late spring or severe summer drought the leaves will take longer to start changing colors.
The exact timing of fall colors arriving is hard to predict but smokymountains.com released this year’s fall foliage prediction map putting most of Michigan in peak colors by Oct. 10 this year.
