Why Do Leaves Change Color in Fall?

Leaves change color in autumn due to changes in pigment production triggered by shorter days and cooler temperatures. During spring and summer, leaves are green because of chlorophyll, the pigment that helps plants convert sunlight into energy. As days get shorter and temperatures drop, trees stop producing chlorophyll, and the green color fades. This reveals other pigments that were always present but masked by the chlorophyll: carotenoids (yellows and oranges) and anthocyanins (reds and purples). Different trees produce different combinations of these pigments, creating the spectacular autumn display. Weather conditions affect the intensity of fall colors: sunny days and cool (but not freezing) nights produce the most vibrant displays. Trees essentially recycle nutrients from their leaves before dropping them, making autumn colors a beautiful side effect of resource conservation.