The brilliant colors that appear every fall in central Indiana will be on display in a few weeks. The typical peak time for fall colors here in Indianapolis are the second and third weeks in October. However, there is no precise time when these changes occur.
So what factors contribute to these fantastic displays of reds, oranges, yellows and browns? And why do these leaves change color anyway?
There are three color pigments associated with leaf color and they are chlorophyll, carotenoids and anthocyanin.
During spring and summer when leaves appear green it is because they’re filled with a pigment called chlorophyll. In the autumn when the days get shorter and the nights longer the chlorophyll production in the leaves slows and eventually stops as light regulates the production of this pigment. As the production of chlorophyll slows, other pigments slowly get exposed and begin to show through in the leaves causing the change in color.
Leaves containing anthocyanin will give a red appearance. Carotenoids are another type of pigment found in some leaves. Leaves containing carotenoids will be orange, yellow, or red. Leaves that contain both anthocyanin and carotenoids will appear orange.
The weather also affects leaf color in the fall even though it’s mainly lack of sunlight causing the leaves to change. Warm sunny days followed by cool nights will generate vibrant red colors for leaves. Rainy or overcast days will create more browns and yellows.