It’s the first day of autumn and the telltale signs are here: Crisp weather, pumpkin spice lattes and most importantly, the leaves are changing colors. Ever wonder why some leaves turn red, others yellow and some just turn brown? It's all down to chlorophyll (more like bore-ophyll!) and the glucose stored inside trees that help reveal the reds, yellows and, less excitingly, browns of fall foliage.