What causes leaves to change color?
In autumn, the days get shorter and the temperatures get cooler. The sun doesn’t warm the leaves as directly or intensely as it did during spring and summer. In these shorter, cooler days, the process of making food within the leaves ceases. As this occurs, the leaves use the food they’ve stored throughout the summer. This causes the leaves’ green pigment to become less dominant, and gives other colors an opportunity to be displayed.