Why Do Leaves Change Color Before Falling?

Leaves are like tiny green factories that make food for the tree using sunlight. In summer, they are busy and stay green because of a special ingredient called chlorophyll. When autumn arrives and days get shorter, the factory slows down. The green color fades away, revealing yellow and orange colors that were hiding underneath all along. Some trees even make new red paints to protect themselves from cold nights. Eventually, the leaf lets go and falls to the ground.

The green stuff is so strong it covers up other colors. Think of wearing a thick green sweater over a bright yellow shirt; you only see green until you take off the sweater. When the tree stops making chlorophyll, the yellow shows through. Wind and cold weather are the final signals that tell the leaf to detach and drop.