Why do some trees turn into a collage of radiant maroon, red, orange, and yellow colors in the fall? Trees are green in the summer because chlorophyll, a green pigment in the leaves, absorbs red and blue light from the sun. The light reflected from the leaves appears green to our eyes.
Chlorophyll is an unstable substance, and bright sunlight causes it to decompose rapidly. Therefore, plants must continuously synthesize and regenerate it. The shortening days and cool nights of autumn, however, interfere with this process. As chlorophyll breaks down, the green colors of the leaves begin to fade. Some trees change from green to bright yellow as the chlorophyll degrades. In others, the action of sugar in the leaves creates a red pigment, causing the leaves to turn maroon, purple, and bright red as the chlorophyll fades.
But why do we have color? It seems to serve no practical purpose—at least none that scientists can discern. And why are there photoreceptors in our eyes that enable us to see it?
I believe that God’s goodness is the point of His creation. He is “good to all, and His tender mercies are over all His works” (Ps. 145:9). He colored the world for our childlike delight. He’s like that, you know.
God’s glory shines through His creation.
Source : http://odb.org