Why Do Leaves Change Color in the Fall?

More than pumpkin spiced lattes and college football, autumn is known for changing, colorful leaves. While most of us like to sit and admire the display of red, orange and yellow on the trees during fall, have you ever stopped to think about why or how leaves change their color? The science behind it all is quite interesting.

There are three major factors that influence fall leaf color: the length of the day/night, weather, and leaf pigments. Unlike summer months, the autumn season includes cooler air as well as shorter days and longer nights. These are significant changes that alters the photosynthesis process and the expression of pigment in each leaf.

Let’s review photosynthesis in order to understand how leaves change their color. All trees contain chloroplasts and chlorophyll in each of their cells, and this is where the process of turning light into energy (or photosynthesis) takes place. This involves the green pigment chlorophyll as a byproduct. However, as there is less sunlight in the day this process slows down and chlorophyll consequently breaks down. Without chlorophyll, the leaves lose their shade of green.

The reds, oranges and yellows that we see on the leaves during the fall are actually colors that have been in the leaves all along. Without the production of chlorophyll, the underlying pigments of the leaves are now exposed. Depending on the type of tree, the leaves may have carotenoids, which are pigments that produce yellows, oranges and browns or they may contain anthocyanins, which produce blue, violet, and red pigments.

The next time you gaze at the changing colors of fall, you’ll have a better understanding (and appreciation) for the complexity that is taking place within those leaf cells. At Mobile Joe’s Landscaping, we love sharing our expertise and passion for the outdoors. If you need lawn advice, please contact us today!