Why Do Leaves Change Color in Autumn?

Updated on June 12, 2018
Beth Eaglescliffe profile image

Friends say I have "green-fingers" and the garden certainly seems to respond to my efforts. I enjoy observing wildlife and being outdoors.

Autumn colors at Hillier Gardens, Hampshire, UK.
Autumn colors at Hillier Gardens, Hampshire, UK. | Source

The Arrival of Autumn

One of the signs that summer is ending is green leaves changing to amazing shades of red, gold, and brown. This doesn’t happen to all trees and the depth and intensity of the colors differs each year. So why do only some trees make this change and what else affects the resultant display? In brief the answer is the type of tree, its location and the weather.

Trees can be either evergreen or deciduous. Evergreen trees are like their name; their leaves remain green the entire year. Deciduous trees are the ones that create beautiful color displays that the fall season is known for. Their show appears just before the tree drops its leaves and lets them fall; hence the alternative name of the fall for the season of Autumn.

A child enjoys playing with brightly colored fall leaves.
A child enjoys playing with brightly colored fall leaves. | Source

Why Are Leaves Like Maple Green in Summer But Orange Red in Autumn?

Fall leave color changes are caused by the following.

  • Green chlorophyll breaks down revealing underlying leaf color.
  • Trees conserve energy as shorter days reduce photosynthesis.
  • Reduced daylight, cooler temperatures, lower intensity of sunlight, more rainfall; these signal winter is approaching and trees enter semi-dormant state.

The color of fall Maple leaves differ by species. For example red maple turns brilliant scarlet, sugar maple leaves go orange-red, and black maple leaves turn vibrant yellow.

Other trees also change their leaf color as the season changes. Oak trees turn red, brown, or russet. Hickory trees go golden bronze, aspen and yellow-poplar trees are golden yellow. Dogwood leaves turn purplish red, beech leaves become light tan in color, and sourwood and black tupelo trees become crimson.

Why Do Leaves Change Color in Fall?

Why Are Leaves Green?

There are three different pigments in leaves. These are caused by chemical compounds called chlorophylls (green), carotenoids (yellow-orange) and anthocyanins (red). For much of the year green is the only leaf color you will notice on a tree as chlorophylls mask the others. Chlorophylls are essential for photosynthesis and are located near the surface of the leaves. Photosynthesis is the process trees use to convert sunlight into energy (sugars) for growth.

As daylight hours reduce, deciduous trees conserve their resources for better times ahead. They stop producing new shoots and shut down their sugar-producing operation. The chlorophylls are no longer required and they breakdown exposing the underlying yellow, orange and red pigments of the remaining chemical compounds.

The bright red autumn foliage of Japanese Acer Japonicum Vitofolium.
The bright red autumn foliage of Japanese Acer Japonicum Vitofolium. | Source

Are you a leaf peeper (someone who chases the fall leaf colors)?

See results

Factors Affecting Timing and Hue of Leaf Color Changes

There is still much discussion in the scientific community about the precise reasons why some autumn displays are spectacular while others disappoint. Some of the many factors that may be involved include shorter days, cooler temperatures, intensity of sunlight, amount of rainfall, latitude and altitude.

It is generally agreed that the major factors influencing the timing and coloration of tree’s foliage are temperature and moisture. It has been observed that lots of warm, sunny days in tandem with cool, crisp but not freezing nights, result in some of the most memorable leaf color displays.

Autumn leaf color at Craigievar Castle, Aberdeenshire, Scotland, UK
Autumn leaf color at Craigievar Castle, Aberdeenshire, Scotland, UK | Source

Experiment to Show Pigment Colors in Leaves

The following experiment can be done as a home science project. It’s a great way to see the hidden colors of autumn. Kids can do this experiment for themselves, but an adult should be close by to supervise!

Items Needed

  • A few green leaves from several trees. Try using leaves from different species including those that you know will change to red or yellow in the fall like maples (acer) or witch hazel.
  • A glass beaker or drinking glass
  • A small amount of rubbing alcohol (Isopropyl).
  • Some plastic wrap (cling-film)
  • Some chromatography or filter paper (you can use coffee filters)
  • A small stake (about 6 inches long) like a pen or pencil.

Fall leaf color depends on the species of tree.
Fall leaf color depends on the species of tree. | Source


Test one type of leaf at a time so that you can compare the result for the different trees at the end of the experiment.

  1. Into your glass beaker put a few green leaves torn into small pieces. (Remember one species only at a time.)
  2. Pour a little rubbing alcohol over the torn leaves; just enough to cover them.
  3. Place a piece of plastic wrap over the top of the beaker to stop the alcohol evaporating.
  4. To speed the process up put the glass beaker into a bowel of hot (not boiling) water. After about 30 minutes all the chlorophyll will have left the leaves and turned the alcohol green.
  5. Take the beaker out of the hot water and remove the plastic wrap.
  6. Cut a strip of filter paper about a half inch wide and tape it to the stake. Place the stake over the beaker so that the filter paper is suspended above the leaf mixture.
  7. Very gently, let the filter paper strip lightly touch the alcohol and pigment mixture. (Don’t let it drop right in!)


The rubbing alcohol and pigment solution will be slowly drawn up onto the filter paper. Be patient and after about an hour, the green color will separate out into its constituent pigments. This process of pigment separation is known as chromatography.

The shades of green, yellow, orange and red show the presence of chlorophylls, carotenoids and anthocyanins. Make a note of which trees leaves produced which colors and look out for them in the fall.

Leaf Color Chromatography

Citizen Science Projects

Some people spend the fall season chasing the magnificent spectacle of changing leaf colors. Many of these are tourists and are known affectionately as “leaf peepers”. A whole industry has grown up to help peepers locate the jewel-like colors before the leaves drop. The best time and places to see these pigments differs each year depending on the weather. Many National Parks and Forests post daily updates on their websites to assist the public in catching the most spectacular displays.

Tourists and locals may also be interested in the science behind the phenomenon. They can take part in citizen science projects. These are often run by university scientists or an environmental non-profit to log changes in time, speed and intensity of the color that occur between years.

Here are some examples of past and present citizen science projects.

  • In US, Pop-Clock was a project run by the University of Maryland Center for Environmental Science to study the impact of climate change on certain trees. As part of the research they asked for volunteer observations of fall color change in their area.
  • In UK, The Woodland Trust is invites everyone to go to their website and record signs of Spring and Autumn on their “Nature’s Calendar”. The details logged should include the date, species and location of the first leaf color change in your area of the UK.

Projects like these depend on funding and so they may run for just a few years or for many. If you’re interested in taking part in this type of activity, do an online search for citizen science projects in your area to see what’s happening local to you.

Finding the Best Fall Colors


Submit a Comment

  • MsDora profile image

    Dora Weithers 

    18 months ago from The Caribbean

    Thanks for the explanation on the changing colors. That's always so mysterious! The experiment you suggest is very interesting and helpful.


This website uses cookies

As a user in the EEA, your approval is needed on a few things. To provide a better website experience, owlcation.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://owlcation.com/privacy-policy#gdpr

Show Details
HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
LoginThis is necessary to sign in to the HubPages Service.
Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
AkismetThis is used to detect comment spam. (Privacy Policy)
HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
MavenThis supports the Maven widget and search functionality. (Privacy Policy)
Google AdSenseThis is an ad network. (Privacy Policy)
Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
Index ExchangeThis is an ad network. (Privacy Policy)
SovrnThis is an ad network. (Privacy Policy)
Facebook AdsThis is an ad network. (Privacy Policy)
Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
AppNexusThis is an ad network. (Privacy Policy)
OpenxThis is an ad network. (Privacy Policy)
Rubicon ProjectThis is an ad network. (Privacy Policy)
TripleLiftThis is an ad network. (Privacy Policy)
Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)