General

Why do leaves change color?

The end of summer may be a bummer, but the beauty of fall foliage helps make up for the colder weather. As the days grow shorter, leaves burst with color.

But have you ever wondered how and why leaves change color? You may be surprised by the science behind it. Here, we’ll explore the basics of nature’s greatest color show:

When do leaves change color?

Credit: ddukang/ iStock

Typically, leaves change color in the autumn. It’s during that transitional period between summer and winter when leaves begin to deepen and darken in color, turning from green into a mix of red, yellow, orange, and even other colors such as purple. The peak time for fall foliage is usually in October, though no two seasons are identical.

The process starts much earlier, though

Credit: borchee/ iStock

While the leaves actually change color in the fall, the process that leads to the color change starts much earlier.

During the spring and summer, those little leaves are prepping for their colorful act This process involves the leaves’ many chlorophyll cells, which are responsible for giving them their vibrant green color. The chlorophyll absorbs energy from sunlight and converts it to nutrients.

The leaves also contain color pigment, which might be yellow or orange thanks to carotene or xanthophyll. But during the warmer months, these colors are covered by the green from the chlorophyll.

Chlorophyll fades, colors emerge

Credit: BrianAJackson/ iStock

As the fall begins to come around and the weather gets cooler and the days get shorter, a tree’s food production process starts to slow down.

Chlorophyll subsequently begins to break down, and the green color fades from the leaves, revealing the additional color pigment that had previously been hidden. It’s like the big reveal at the end of a makeover show.

The leaves are rarely just one single color, though. Additional chemical changes can create variances and beautiful gradients of color within the leaves.

No two fall foliage seasons are alike

Credit: borchee/ iStock

Variables such as weather, amount of daylight, and rainfall will affect how long the fall foliage lasts and the intensity of the color. For instance, early frost can reduce bright reds in leaves, and rainy days can increase the intensity of the color overall.

Not all trees lose their leaves

Credit: zefart/ iStock

Here’s something that you may not know: not all trees will lose their leaves in the fall. It’s primarily deciduous trees that lose their leaves.

Conifer trees, on the other hand, aren’t so quick to change and drop their leaves. This includes trees such as pine, spruce, and cedar, which are “evergreen,” meaning they stay mostly green year-round. Sure, they’ll drop some needles, but it’s nothing quite as dramatic as the fall foliage show that their deciduous cousins put on annually.

Have a ball this fall

Credit: Kirkikis/ iStock

The phenomenon of leaves changing color is a joy to behold each fall season. Now that you understand what makes leaves change color, be sure to get out there and enjoy the relatively short season of fall foliage while it lasts.