Reported by: Cyndee O'QuinnHave you ever wondered how the leaves change into their beautiful colors of fall? Why are some trees yellow, while maples turn into a brilliant red and oaks are brown?
It is a process that is triggered not only by the weather but by the shorter days and longer nights.
If we had a magic eraser, we would find out that underneath the green color of the leaves hides fall’s festive colors. The green color is produced by chlorophyll.
Chlorophyll is the chemical that is needed for photosynthesis. Photosynthesis occurs when plants and trees use sunlight to change water from their roots and carbon dioxide in the air to sugar. The tree uses this sugar known as glucose for food.
When the amount of sunlight starts to decrease, trees begin to produce less chlorophyll until gradually there is no more. As the chlorophyll in the leaf fades, the carotenoids are allowed to show through and we can see the leaves' true colors.
Carotenoids produce the bright yellow and oranges in leaves that we see and are found in vegetables like corn and carrots.
Chlorophyll and carotenoids are found in leaves all the time but anthocyanins which produce the red color form only in the fall and in some trees. Photosynthesis during the day produces glucose, but the cooler nights trap the sugar in the leaves.
Anthocyanins allow the tree to retrieve the trapped nutrients from the leaves and in the process produces the beautiful red, crimson and purple colors. Anthocyanins are what give apples and strawberries their red color.
The best forecast for beautiful fall foliage is a warm, wet spring and a summer that is neither too hot nor dry. Add to that a sunny, warm fall with cool nights and you can expect a spectacular array of fall colors.
However, drought stress will cause leaves to turn yellow and brown prematurely and fall off. One tree that normally has brown leaves is an oak tree. The brown color comes from the waste that collects in the leaves.
