Why are leaves different colors? What to know as the fall season begins in NC

Fall is officially here, and it won’t be long before leaves transform into vibrant shades of red, orange, and yellow.

Leaves in Charlotte aren’t expected to change until the end of this month, according to Appalachian State University’s fall color map. Still, there are plenty of places around the Carolinas where you can venture out and admire the fall foliage.

But why do we see different colors of leaves on trees that are bunched together?

Here’s the science behind what leads to the multicolored displays in the fall.

Why do leaves change color in the fall?

Leaves are green during the spring and the summer because they make chlorophyll, which helps them produce energy from sunlight, according to the National Oceanic and Atmospheric Administration. This process is known as photosynthesis.

During fall, when the days get shorter, leaves stop making chlorophyll. Once that happens, the green color starts to fade, and red, orange, and yellow colors begin to appear, according to NOAA.

So, why are the leaves different colors?

It has to do with pigments inside leaves and species of the trees they grow on. In addition to chlorophyll, three pigments in leaves produce different colors, NOAA explains:

• Xanthophylls (yellow)

• Carotenoids (orange)

• Anthocyanins (red)

Leaf colors also depend on the species of the tree, according to the U.S. Department of Agriculture:

• Oaks: red, brown, or russet

• Hickories: golden bronze

• Aspen and yellow-poplar: golden yellow

• Dogwood: purplish red

• Beech: light tan

• Sourwood and black tupelo: crimson

Maple leaf colors also vary by species, the USDA says. For example, red maples produce red leaves, while black maples have yellow leaves during the fall.

How does weather affect the color?

Many leaves have different pigments that produce rich colors but won’t show when weather conditions aren’t ideal.

Strings of warm days and cool nights in the fall are when most colors are displayed, according to the USDA.

“During these days, lots of sugars are produced in the leaf, but the cool nights and the gradual closing of veins going into the leaf prevent these sugars from moving out,” the USDA says. “These conditions spur production of the brilliant anthocyanin pigments, which tint reds, purples, and crimson.”

According to the USDA, carotenoids are always present in leaves, meaning yellow and gold colors are usually consistent yearly.