It’s time to say hello to fall. With cool, crisp mornings, bright blue skies and the brilliant, colorful foliage display, no wonder autumn is a favorite time of year. The leaves are changing color.
Just how do the leaves go from deep, rich green to the fall defining colors of bright gold, orange and red? It’s an amazing process that only Mother Nature could pull off.
The days grow shorter, meaning less sunlight and less rainwater. The tree no longer produces chlorophyll. Without that, the leaves soon turn brown and die, but the transformation is one of the most beautiful displays in nature.
All of the colors (pigments) that we see during the fall season are contained in the leaf all along. The combination of sunlight and water that the tree received during the spring and summer will determine just how brilliant its fall colors will be. Here’s how it works:
Leaves themselves are pretty amazing. They’re like mini food factories, using sunlight, water and carbon dioxide-what we and animals exhale-to produce food and oxygen through the process of photosynthesis. During photosynthesis, leaves convert the carbon dioxide into oxygen, which is necessary for life. This is why rainforests are often called “the lungs of the planet.”
The leaves of spring and summer are green because of chlorophyll. At the end of the summer season, the trees stop producing it, allowing the other hidden pigments in the leaf to come out. The amount of glucose (sugar) is another factor in determining the color of the leaf.
During the fall season, carotenoids and xanthophylls take over and turn the leaves from green to varying shades of yellow and orange. The red hues come from anthocyanins. These are not contained in all leaves and only appear under certain circumstances.
Anthocyanins are produced during dry and sunny conditions to protect the leaves from too much sunlight. Anthocyanins also cause more sugar or glucose to be produced in the tree sap in a final push to create as much energy as possible to help the tree during winter. When the spring and summer have been excessively rainy, you won’t see too much red color in fall. Without lots of sunlight, the tree doesn’t need to produce anthocyanins to protect the leaves.
The height of the color changes lasts about three weeks as the leaves go from green to yellow to orange and red as the last of the nutrients are taken by the tree. The leaves die and fall from the tree, leaving a scar.
Hopefully the trees got enough sun and rain this summer and will give us a beautiful display of fall color.
Be sure to check out Mother Nature at her most colorful. The best time to see the leaves change in our area begins near the end of October through mid-November.
- Look it up: Use the Internet and other reference sources to learn more about photosynthesis and how leaves change color. Learn about the different types of leaves
- Talk about it: The trees are getting ready for winter. What other ways does nature prepare for the cold winter months ahead? How will you get ready?
- Collect fall leaves: As the leaves change, try to collect as many different colors and kinds of leaves that you can find. Do you know what kind of tree they came from? You can make a collage or other type of fall decoration for your class or room using your leaf collection.
This week in black history Oct. 17-24
- The first organized Black bank, the Capital Savings Bank of Washington, D.C., opened on Oct. 16, 1888.
- The first Blacks elected to the House of Representatives were Republicans Joseph H. Rainey, Robert C. Delarge and Robert B. Elliott. They won three congressional seats in South Carolina on Oct. 19, 1870.
- The first Black-owned insurance company, North Carolina Mutual Life Insurance Company, was started by John Merrick on Oct. 20, 1898.
- On Oct. 21, 1979, the Black Fashion Museum was opened in Harlem by Lois Alexander to showcase the contributions of Blacks to the fashion industry.