Leaf Senescence: The Magic of Fall Color


Autumn is quickly approaching and with it brings a wondrous display of ephemeral beauty. It shows up almost overnight and never overstays its welcome. Fall color, of course, is the long anticipated signal that the dog days of summer have finally ended. Warm sweaters, hot cider, bonfires and football games (GO BUCKS) - we made it.

Around this time each year I get a little giddy. I know it’s coming and I seriously cannot wait. All those reds, purples, oranges and yellows, dancing on the breeze as I drive down the street. It’s spectacular. Recently I was trying to explain the phenomenon of the fall to my children while on the way home from piano practice. My arborist self started using words like: chlorophyll and photosynthesis. “Photosynthe-what?” my youngest repeated. Exactly. I resorted to the simplest explanation: Trees have magic powers. That made total sense to them, of course they do. But seriously, have you ever stopped and wondered why trees change color?

Here’s the simplest arborist’s answer:

During the growing season trees are making food through a process called photosynthesis. Isn’t that incredible - trees make their own food! (Magic.) The magic is due in part to the chlorophyll stored in each leaf, which absorbs energy from the sun to transform carbon dioxide and water into plant food (glucose) and oxygen. During the process of “photosynthe-what”, chlorophyll absorbs red and blue wavelengths of light from the visible light spectrum and reflects green wavelengths of light, which is why leaves are green during the growing season.

Around this time of year the days grow shorter and less sunlight is available to make plant food. Coupled with decreases in daily temperature, chlorophyll begins to break down in each leaf. As the chlorophyll absorbs less light, the green color fades away leaving behind the pigments hiding beneath: those incredible reds, purples, oranges and yellows. Totally magical.

How fortunate to live in a section of the world that offers such spectacular displays of fall color. Living amongst an abundance of deciduous trees we experience the beauty of this chemical reaction whether we know why it happens or not. From all of us at Russell Tree Experts, we wish you a very Happy Fall and remember if anyone ever asks you why trees change color, it’s accurate to answer: Trees have magic powers.


Shari Russell
Co-Owner, Russell Tree Experts