Southern Roots

The True Color of Leaves

By Verna Gates | Photography courtesy of departures.com

Contrary to popular belief, the fall reveals the true color of leaves.

“What color are these leaves?” is my favorite trick question in the summertime. Without fail, the answer is green. I shake my head, “no.” 

We charmingly say the leaves are turning colors in the fall. The truth is, the color is returning.

Remember spring? In that delightful season, we see the soft greens that are almost yellow peeking out on tender leaves. Within days the chartreuse gives way to darker and darker greens as the leaves mature. By the time the air conditioning is on full blast, the greens are rich and intense. What changed? The tree went into full food production. 

What you are seeing is chlorophyll. This food-making catalyst absorbs the blue and some of the red in light in the electromagnetic spectrum, reflecting green into our eyes.  

Growing children and trees
It takes a lot of effort to raise a human child to six-feet tall, but trees miraculously grow to 100 feet just by transforming light, water and air. A sapling comes equipped with the ability to make its own dinner and soon grows into the sky. Human parents should be jealous. 

Chlorophyll serves as the tree’s chef and dinner table. This photosynthetic pigment traps the sun’s light energy, which mixes with carbon dioxide and water to make the sugars that feed plants. This photosynthesis (photo means light while synthesis means process) feeds the tree, shrub, flower or tomato plant. The by-product, oxygen, gives us the air we need for our lungs. 

The tree supports the growth of chlorophyll by supplying water to the leaf stem, which spreads out along the leaf. Chlorophyll will naturally fade during the summer so the hungry tree will pump in water to support its food manufacturing component, plumping the green stuff back up. During a summer draught, you may see fall colors emerge. That means the tree is too thirsty to keep up food production. 

Changes they are a-comin’
As the days grow shorter and the temperatures drop, the tree begins its dormancy process. Except for the evergreens (such as pines, firs, cypresses, and spruces), trees shut down for the winter and live off of the glucose stored in the roots. It’s as if the roots were canning food all summer long, storing up a full pantry to feed the tree through the winter. 

The once fluid leaves will now sputter on less water coming up from the roots in the fall. The tree no longer needs to produce food and is dumping its chlorophyll. You can see the green start to recede from the leaves. Early in the fall, you see green still dappled in the leaves. Once full dormancy is reached, the chlorophyll fully retreats, revealing the vibrant colors that existed all along. 

Other chemicals tint the colors you now see. Yellow comes from xanthophylls, a carotenoid (think carrot) that you can also see in the yellow yolks of eggs. To get a bit technical, xanthophylls contains oxygen while the orange colors are made with hydrocarbons. The orange colors are carotenoids as well, but like our carrots, contain the hydrocarbons, which are the basis of carbohydrates. Reds and purples contain anthocyanins, a type of flavonoid that color red wine, eggplant, blueberries and cherries. Anthocyanins produce the antioxidants that give these foods a healthy boost.  

Find out for yourself 
If you want to see these colors in the summertime, a simple experiment will bring out the colors. Take a green leaf, pound it into a coffee filter to release the chlorophyll. Place the leaf in a cup and pour a half inch of alcohol on top. Stick the coffee filter in so that the bottom is in the cup and the top hangs out of the cup. Check back to see the green pulling away from the leaf, giving you a preview of fall. 

Trees are magnificently more complex than their beautiful green, red, golden, purple and orange leaves. They live on a slim band of bark that transfers water up and glucose sugars from photosynthesis down to the roots. Scientists speculate that trees may be able to communicate through their root systems to share resources and may even be able to keep a mother tree alive by sharing water. They certainly are the chameleons of the plant world. 

By the way, your yard needs the chemical compounds found in these leaves. They are the best fertilizer available and freely given. As one famed Alabama gardener, Bill Finch, once said, “If you take one leaf out of your yard, you will get the bad soil you deserve.” 

Step outside to see the true color of tree leaves as the chlorophyll recedes, leaving the real tints behind. And enjoy the leaves on the trees and in your flower beds!

Read More in DeSoto Magazine online.