Leaves change color in autumn due to a complex chemical process triggered by shorter days and cooler temperatures. During summer, leaves contain high levels of chlorophyll, which gives them their green color. As autumn approaches, trees stop producing chlorophyll, revealing other pigments that were always present but masked:
- Carotenoids produce yellow and orange colors
- Anthocyanins create red and purple hues
- Tannins result in brown colors
The timing and intensity of fall colors depend on several environmental factors including temperature, rainfall, and amount of sunlight. The most vibrant displays typically occur when autumn has bright sunny days followed by cool nights above freezing.