Red, however, is another matter. It’s made on purpose. As chlorophyll diminishes in fall, a red pigment, anthocyanin, which was not previously present, is produced in the leaves of certain tree species, such as maples, oaks and dogwoods. The anthocyanin makes their fall leaves predominantly red.
Scientists don’t fully understand why trees produce anthocyanin. One hypothesis is that the red leaves play a protective role as the tree prepares for winter senescence.
Regardless of color, most autumn leaves will have fallen to the ground, their nutrients recycled, by late November.
IN THE SKY: From David Dundee, Tellus Science Museum astronomer: The moon will be new on Sunday. Both Mercury and Venus are low in the west just after dark. Venus sets shortly thereafter. The two planets will appear near the crescent moon on Monday evening. Jupiter is low in the southwest around dusk and sets a few hours later. It will appear near the moon on Thursday night. Saturn is low in the south just after dark and sets in the west around midnight.