As we get ready for the splendor of fall foliage, Compound Interest explains the science of autumn leaves with his signature infographics:
Carotenoids and flavonoids are both large families of chemical compounds. These compounds are present in the leaves along with chlorophyll, but the high levels of chlorophyll present in the summer months usually masks their colours. As the chlorophyll degrades and disappears in autumn, their colours become more noticeable – both families of compounds contribute yellows, whilst carotenoids also contribute oranges and reds.
Check the link for the graphic and more detail.