The leaves of some trees such as birches, tulip poplars, redbud and hickory are always yellow in the fall, never red. The fall leaves of a few trees, including sugar maple, dogwood, sweet gum, black gum and sourwood, are usually red but may also be yellow. Unlike the bright colors of flowers, which attract pollinators, or the bright "Warning Colors" of many kinds of animals, the bright colors of fall foliage are a byproduct of chemical changes as the trees start to go dormant. These co