Here is the aspen range in North America.
Aspen stars in the greatest fall color show going west of the Mississippi River. As an aspen leaf's chlorophyll fades, a group of colored pigments called carotenoids show. Like chlorophyll, carotenoids are contained in the plastids, tiny structures in leaf cells. Carotenoids are the yellow we see each fall in aspens.
More Autumn Leaf Photos
What are Carotenoids and Plastids?
More on Quaking Aspen


