Next a layer of cells at the base of each leaf hardens. This hardening shuts off the flow of moisture from the tree to the leaf. Without chlorophyll and long hours of sunlight to keep the leaf healthy, the green coloring fades and other colors become more prominent. The yellows we see come mainly from carotin and xanthophyll, the same substances that color carrots and egg yolks. The reds and purples come from tannins and anthocyanin, like the pigments of grapes and red berries.
Leaves fall when all the cells break down and harden at the point of attachment to the branches.
When the tree has no leaves, it is resting, in a condition called dormancy, conserving its energy to survive the winter. The clear, crisp days that accompany these spectacular changes offer the perfect opportunity to get out and explore Maryland's byways and back roads to experience these changes firsthand. Here are some suggestions, starting in Western Maryland. The autumn foliage is at its peak in most Central Maryland areas, and in some areas the leaves have already started to drop. Gunpowder State Park is reporting spectacular conditions, particularly in the Hammerman and Hereford areas.