Why do leaves change in the fall?

By Sally Zimmerman, MNA Intern

Colorful trees in Estivant Pines Nature Sanctuary. Photo by Marianne Glosenger.

Colorful trees in Estivant Pines Nature Sanctuary. Photo by Marianne Glosenger

There is nothing quite like the colors one can see in Michigan in the fall. Reds, oranges, yellows and browns cover the trees and make for a beautiful sight, whether you’re on a hike or just driving by. Many people are delighted by fall and the wonderful colors, but don’t fully understand why the leaves change in the first place.

Many of the colors seen in fall are always present in leaves, just hidden by an abundance of chlorophyll. Chlorophyll is what makes leaves green and is regulated by light. When there is plenty of light, like in the summer months, the green overshadows the other colors of the leaf.

When the days start to get shorter and there is less light, less chlorophyll is produced. The chlorophyll starts to decompose, and without new chlorophyll being produced, the green color of the leaf starts to fade.

Changing leaves at Klipfel Memorial Nature Sanctuary. Photo by Marianne Glosenger

Changing leaves at Klipfel Memorial Nature Sanctuary. Photo by Marianne Glosenger

At the same time that this is happening, high levels of sugar concentrations in the leaves lead to increased production of anthocyanin and carotenoid pigments. Anthocyanins cause leaves to appear red, and carotenoids cause leaves to appear yellow. A leaf that has a combination of the two will appear orange. If a plant has neither of these pigments, it may appear brown because of other plant chemicals, such as tannins.

All of this might seem a bit heavy, but it will come in handy on any of MNA’s upcoming fall events! There are hikes, volunteer days and exploration days all throughout the months of October and November that anyone can attend to see the beautiful fall colors in action.

Some of these upcoming events include a field trip to Newaygo Prairie on October 19, an exploration of Braastad Nature Sanctuary on October 23 and an exploration of Fox River Nature Sanctuary on October 30. To learn more, visit the MNA website or call (866) 223-2231.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s