Why do the leaves change color in fall?
As the long, warm days of summer transition to a darker, cooler winter, leaves across much of the country put on a dazzling display of colors. And as it turns out, the oranges, reds, browns and yellows that draw leaf-peepers are the true colors of the leaves that have been hiding beneath the green all summer.
Just as humans eat food for energy, plants "eat" sunlight in a process called photosynthesis.
When sunlight hits a leaf, it sets off a chemical reaction that produces chlorophyll to turn that light into energy for the plant. Chlorophyll is green, which is why leaves are green during the summer months.
As the days get shorter during the fall months, the plants stop 'eating' as much. Fewer hours of light hitting the plant means less green chlorophyll coating the leaf. This allows the leaf's true color to be revealed – the fall colors we all enjoy.
The brightest fall colors typically come when a wet spring and summer are followed by a cool, sunny autumn. A warm period in the fall can mute the intensity of autumn colors.
Fall colors are only seen in parts of the country with deciduous, broad-leaved trees that drop their leaves as winter approaches.
