Evergreens are a beacon of hope in the middle of winter, something green amid the gray skies and white landscapes. But why? How are they able to stay green while deciduous trees (oaks, maples, birch, etc.) lose their leaves in the fall? Both evergreens and deciduous trees get their green color from chlorophyll, which is required for photosynthesis, the process which plants use to make their food. It requires both sunlight and water. In the fall, when days get short, and less sunlight is available, deciduous trees lose their chlorophyll, the green fades, and the color show begins. But as the leaves dry out, the fading continues, and the leaves eventually drop.