Understanding Fall Leaf Color Change

Mother Nature treats us to a unique spectacle of leaves changing color every fall. But what triggers the fall leaf color change from a biological point of view? Varying theories exist to explain away the gorgeous seasonal display everyone loves so much, and scientists have worked hard for years to better understand these changes in trees and shrubs. 

Here’s more from top-rated providers of tree arborist services in West Chester, PA.

Chlorophyll Degradation: Green Means Go

Contrary to popular belief, trees primarily change color because of the changes in sunlight or a lack of sunlight rather than autumn’s chilly weather conditions. As the autumn days shorten, the change in the light triggers deciduous plants to stop transporting sugar production in leaves for growth. To do that, the plants kickstart the chlorophyll degradation process. 

You probably already know that chlorophyll gives leaves their characteristic green color. It also plays a primary role in absorbing sunlight so that the plant can photosynthesize. However, as shortened sunlight exposure triggers chemical changes in the plant, a corky wall of cells forms between the leaf stalk and the twig to stop this translocation.

As these cells multiply, they seal off vessels that supply the leaf with water and nutrients. They also partially block exit vessels, essentially trapping simple sugars in the leaves. So, the combination of reduced sunlight and less water and nutrients stops the trees from breaking down chlorophyll, which means the green color fades.

Only when the green color of chlorophyll fades do other color pigments shine through. Chlorophyll degradation simply reveals the underlying yellows and reds that make autumn special.

What Causes the Fall Leaf Color Changes to Bright Yellows and Reds?  

The following pigments explain the various leaf colors:  

• Anthocyanins give leaves their deep red and purplish hues  
• Carotenoids give leaves their brilliant yellow and orange colors  
• Leaves turn brownish or tan-colored because of tannins

Leaves typically have carotenoids all summer, but chlorophyll masks the color during the growing season. However, plants freshly produce anthocyanins as autumn conditions ramp up. 

Scientists have various theories to explain why trees would produce a new pigment while otherwise trying to save their resources for the harsh winter ahead. But the research hasn’t landed on an answer just yet.

Don’t Forget About The Sunlight and Temperature Effects  

While fall leaf color changes have daylight to thank for it, temperature and precipitation seem to contribute to the intensity of these color changes. For example, decreasing daytime temperatures lead to more vivid colors.

Count on Your Local Tree Experts for Help

You’ve invested a lot of time and effort into your property’s beautiful trees. Why not protect your investment with honest, accurate, and objective tree care maintenance and recommendations from Rick’s PHC Certified Arborists? Services include the following: 

• Residential tree care  
• Deep root feeding  
• Growth regulation methods
• Soil and trunk injections and more

Call Rick’s PHC Certified Arborists at (610) 840-2655 today to schedule a free estimate. We’ll tell you everything you need to know, from why fall leaf color changes occur to the best trees for your front yard in and around Westchester, Pennsylvania.