The Fall Leaf Cycle starts at the end of summer with the shortening of the days and cooler nights. At that point, the trees do not receive enough light to produce food for themselves, and the production of chlorophyll is stopped. Some trees that turn fire engine red, like a Maple, have glucose trapped inside it. A combination of sunlight, shade, and the cold nights help turn the glucose into this red color we see. I have seen some of the most spectacular colors of my life in New England and along the Appalachian Trail. Shenandoah National Park offers some of the best vistas and hiking trails in the East!