Q: I know I learned this long ago, but I have forgotten the answer and my child is asking why the leaves change color in fall. Could you tell me so I can remain the “answerer of all questions” for her?
A: There is a terrific article online by the State University of New York College of Environmental Science and Forestry about this phenomenon. According to ESF, “in the fall, because of changes in the length of daylight and changes in temperature, the leaves stop their food-making process. The chlorophyll breaks down, the green color disappears, and the yellow to orange colors become visible and give the leaves part of their fall splendor. At the same time other chemical changes may occur, which form additional colors through the development of red anthocyanin pigments. Some mixtures give rise to the reddish and purplish fall colors of trees such as dogwoods and sumacs, while others give the sugar maple its brilliant orange. The autumn foliage of some trees show only yellow colors. Others, like many oaks, display mostly browns. All these colors are due to the mixing of varying amounts of the chlorophyll residue and other pigments in the leaf during the fall season.”