Science
How do leaves change color in autumn?
Leaves change color in autumn because trees stop making chlorophyll, the green pigment used for photosynthesis. As the green fades, yellow and orange pigments that were always there get revealed, while reds are made fresh — before the leaves fall.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how autumn leaves works.
Step by step
- 1Shorter, cooler days signal trees to stop photosynthesis.
- 2Green chlorophyll breaks down and fades.
- 3Hidden yellow and orange pigments are revealed.
- 4Red pigments are newly produced in some trees.
Frequently asked questions
- Why do leaves change color in autumn?
- Trees stop producing green chlorophyll, revealing yellows and oranges and making new reds before leaves drop.
- Why do leaves fall off in autumn?
- Trees seal off leaves to conserve water and energy through winter, so the leaves die and drop.
- Why are some autumn leaves red and others yellow?
- Yellows and oranges are revealed as green fades; reds are freshly made from sugars trapped in the leaf.