Why Do Leaves Change Color in the Fall?

Why Do Leaves Change Color in the Fall?

For parts of the country with cooling temperatures and large populations of deciduous trees, the next six weeks will provide some wonderful scenery. Green leaves will give way to a colorful natural skyline with hues of reds, yellows, oranges and browns 

But what gives leaves their fall color palette? The answer can be found in four pigments:

  • Chlorophyll

  • Carotenoids

  • Anthocyanins

  • Tannins

Present throughout the year, chlorophyll gives leaves their green color during the growing season. It is essential to the production of carbohydrates and photosynthesis. But if chlorophyll is present year-round, why don’t leaves stay green? Another pigment is also present during the growing season: carotenoids. During the spring and summer, however, high chlorophyll levels overpower carotenoids, and leaves stay green. While remaining present, chlorophyll levels dip in the fall, allowing carotenoids to become more visible. This gives leaves their yellow color.

Red color in leaves in the product of anthocyanins. As you might have deduced, orange leaves are created by the presence of both carotenoids and anthocyanins.

A pigment not found in most trees during the growing season, anthocyanins develop with cooler night time temperatures. Paired with ideal weather conditions, anthocyanins play a large role in creating more intense fall colors. A combination of temperatures between 32-45 degrees at night and bright sunny days are peak conditions for trapping sugars in leaves, allowing anthocyanins to develop and enhance color. Avoiding big storms that can pull leaves off trees prematurely also helps anthocyanins develop more completely.

The fourth pigment, tannins, typically are found in oak trees, giving leaves a dull brown color. Oaks that have been fertilized show more of a red color before tannins fully develop. Like anthocyanins, tannins are not present in growing season.                                               

For more tree science insights from the Davey Tree team, sign up for our email newsletter and get our latest tree talk delivered directly to your inbox. 

Add a comment:
Related Blog Posts
  • Can I Use a Pressure Washer to Clean or Spray Trees?

    Tim said, “I’ve been noticing more people in my area using power washers to ‘clean’ their tree trunks.”

    He wanted to know if we recommended washing trees with power washers. And we often get asked if it’s okay to use a power washer to spray insecticides on trees.

    Read More
  • Is My Tree Dying or Dead? Here’s How to Tell and What You Can Do

    Bryan, a Davey blog reader from British Columbia was “concerned that some of our trees might be dying or in danger of falling on our house or other buildings,” and wanted to know some dying tree symptoms.

    A dead or dying tree is nothing to play guessing games with. Take these simple steps to check on your tree and find out just what it needs.

     

    Read More

Request a consultation

What do you need services for?
Sorry, we can’t seem to find the zip code you specified. Our residential tree care offices may not service your area. If you believe this is an error, please try again. Need help? Email us at info@davey.com.
  • Email newsletter
  • Woodchips
*Please fill out all required fields.