Most anthocyanins are produced in the autumn, in response to bright light and excess plant sugars within leaf cells. During the growing season, chlorophyll is continually being produced and broken down and leaves appear green. As night length increases in the autumn, chlorophyll production slows down and then stops and eventually all the chlorophyll is destroyed. The carotenoids and anthocyanins that are present in the leaf are then unmasked and show their colors. Certain colors are characteristic of particular species.
Striped maple becomes almost colorless.
Leaves of some species such as the elms simply shrivel up and fall, exhibiting little color other than drab brown. The timing of the color change also varies by species. Sourwood in southern forests can become vividly colorful in late summer while all other species are still vigorously green. Oaks put on their colors long after other species have already shed their leaves. These differences in timing among species seem to be genetically inherited, for a particular species at the same latitude will show the same coloration in the cool temperatures of high mountain elevations at about the same time as it does in warmer lowlands.