Why do leaves turn red, orange, and gold, and when will color peak where you live? In Understanding Autumn Leaf Color Change in Trees, Eric Silveira and Prof. Rick Harper explain what happens inside a leaf as the seasons change. Harper, a UMass Amherst extension professor, also spoke to ABC News about what to expect as the season moves across the U.S., and why average peak dates are a good guide for planning a foliage trip. To see how color is spreading across Massachusetts, check the MDAR Fall Foliage Map.