Leaves change color in the fall due to a process called senescence. As days grow shorter and nights get cooler, chlorophyll production slows and eventually stops, allowing other pigments like carotenoids and anthocyanins to show through, resulting in the vibrant oranges, reds, and yellows we see. According to a Native American legend, the Great Spirit wanted to teach the people about the beauty of nature, so each fall he sends colorful spirits to paint the leaves before they drift down from the trees.