Watt, Why & How e-Newsletter

How Do They Do That? Fall Colors

AutumnThe splash of colors on autumn leaves is one the most beautiful images in nature. It can also leave parents fumbling for a response when children ask, "why do leaves change color?". You think it has something to do with shorter days and cooler weather, but maybe you're not exactly sure.

So, why do leaves change their hue? Scientists have been studying this issue for a long time and it seems that three factors affect autumn colors: leaf pigments, length of night and weather.

Three little pigments

A pigment is a natural substance that produces color in plants and animals. There are three pigments present in leaves that play a part in autumn color changes.

  1. Chlorophyll gives leaves their basic green color. It's necessary for photosynthesis, the chemical reaction that allows plants to use sunlight to make food.
  2. Carotenoids, which produce yellow, orange and brown colors in such things as corn, carrots and daffodils.
  3. Anthocyanins, which give vivid color to fruits such as strawberries, cherries and blueberries.

Like night and day

The color change is primarily driven by the calendar—that is the increasing length of night in late summer and early autumn. As daytime grows shorter, chlorophyll production slows down and eventually stops. The carotenoids and anthocyanins that are present in the leaves are then unmasked and show their colors.

Under the weather

Temperature and moisture can affect which colors appear and the brilliance of the display. For example, lots of warm, sunny days and cool nights in early autumn can bring about the most spectacular array. These conditions lead to the production of anthocyanin pigments, which create more red and purple leaves.

Moisture in the soil plays a part as well. Drought conditions in summer can delay the onset of the leaf changes as well as the mix of colors. Typically, it's a combination of weather conditions that has the biggest impact, making each autumn display different.

Branching out

Individual tree species tend to display certain colors, according to the U.S. Forest Service. Here are some well-known examples:

  • Oak—red or brown
  • Maple—scarlet, orange-red and yellow
  • Hickory—golden bronze
  • Dogwood—purplish red

Sadly, leaves from some species, such as elms, simply shrivel up and fall to the ground. They show little color other than a drab brown.

Like people, tree species often run on their own schedule. Sourwoods in southern forests become very colorful in late summer when other trees are still sporting green. Oaks on the other hand, are still showing off their colors long after other species have shed their leaves.

So there you go. The next time some child asks you why leaves change color, just come back to this article and you'll have the answer!


More From APCO

Sign Up Now Pay Online for Free with Paperless Billing

Pay Online for Free with Paperless Billing

Learn more

Download our new app

How We Restore Power Learn more

How We Restore Power

Learn more Create Your Own Emergency Outage Kit

Create Your Own Emergency Outage Kit

Visit AEP.com
Use of this site constitutes acceptance of the AEP Terms and Conditions. View our Privacy Policy. © 1996-2019 American Electric Power. All Rights Reserved.

Privacy Policy

Privacy Policy for Appalachian Power, a unit of American Electric Power (AEP)


This Privacy Policy applies only to AppalachianPower.com and the Appalachian Power customer mobile app (com.aep.customerapp.apco). Other AEP websites and apps may be governed by their own privacy policies, appropriate to the uses and needs of each. Throughout the site or app, we may provide links to resources and sites that are not part of AppalachianPower.com or the Appalachian Power customer mobile app. This Privacy Policy does not apply to those resources and sites.


By using this site or app, you consent to the terms of this Privacy Policy. Whenever you submit information via this site or app, you agree to the collection, use, and disclosure of that information in accordance with this Privacy Policy.

Information Collected

  1. Passively collected information

    During your use of this site or app, we may collect anonymous information about your visit here through the use of server logs, cookies, scripts, tracking pixels and other Web traffic tracking systems. This information is aggregated and used to improve user experience through analysis of user activities. This information is never combined with any of the personally identifiable information you may provide in your use of the features of this site or app.
  2. Personally identifiable information

    On certain forms of this site or app, you may be asked to provide information about yourself or your account with us, either to identify yourself to us or to request a service from us. In each case, we will inform you what information is provided at your option and what information is required to complete the transaction or activity you are engaged in. If you are unwilling to provide this required information, you will be unable to complete the requested transaction.

Use and disclosure of information

The information you provide to us will be used to respond to requests you may make for services. Some or all of this information may be added to your permanent account record and may be used for research purposes.

In addition, we may use elements of this information in the following situations:

  1. We may transfer the information to Appalachian Power’s affiliates and subsidiaries, unless such transfer is prohibited by law;
  2. We may transfer the information as part of a merger, consolidation, acquisition, divestiture or other corporate restructuring (including bankruptcy);
  3. We may make the information available to third parties who are providing the product, service or information that you have requested (but not your password);
  4. We may make such information available to third parties who are providing services to Appalachian Power (for example, providing the information to third parties performing computer-related services for Appalachian Power);
  5. We may use the information to communicate with you about products and services that may be of interest to you.
  6. We may disclose the information if we form a good-faith belief that disclosure of such information is necessary to investigate, prevent, or take action regarding any illegal activities or regarding interference with the operation of our site or violation of its terms of use; or
  7. We may disclose the information if we believe that disclosure is required by law or regulation or in response to a subpoena or other order of a court or other governmental agency.

Appalachian Power uses Flurry Analytics Service (provided by Yahoo) in order to improve its mobile apps. Flurry’s privacy policy governs the use of this information.

Also, Appalachian Power reserves the right to share any aggregated information (i.e., non-personally identifiable information) with any third parties for any reason, unless prohibited by law.

We will not sell, rent or otherwise disclose the information we gather about you or your account to any third party, except as outlined in this Privacy Policy.


Appalachian Power takes reasonable steps to protect your personally identifiable information as it is transferred to us, through the use of Web technologies such as the Secure Sockets Layer and others. However, no Internet transmission of information is ever completely secure or error-free. In particular, e-mail sent to or from Appalachian Power may not be secure.

How to Reach Us

If you would like to update your personally identifiable information or if you have questions about this privacy policy, please contact us.

Changes to This Policy

Appalachian Power reserves the right to change this Privacy Policy at any time. If this Privacy Policy changes, the revised policy will be posted to this site. Please review this Privacy Policy before you provide any personally identifiable information through this site. Use of our web site after the posting of a revised privacy policy constitutes your consent to the revised policy.

This policy was last revised on December 13, 2017.

Close ×

Sign Up For Alerts

Subscribing to APCO alerts gives you instant notification for:

  • Billing & Payments - avoid late payments and disconnection
  • Outage Updates - find out if there's an outage at your address and when power will be back on

Win an Xbox One with Alerts!

Enroll in alerts to be eligible to win. Subscribing to I&M alerts gives you instant notification for:

  • Billing & Payments - avoid late payments and disconnection
  • Outage Updates - find out if there's an outage at your address and when power will be back on

Loading video...