As the days get cooler and shorter, nature puts on a gorgeous display of color as the leaves change — red, yellow, orange and, yes, even brown. In the fall, the trees show you their REAL color. Leaves are green due to chlorophyll and photosynthesis. But when the production of chlorophyll slows and then stops as the season begins to change, then the chlorophyll disappears completely and VOILA! We see the leaves in their true glory. A number of things factor into the change to fall colors.