Why Autumn Leaves Explode Into Color At Different Times On The Same Tree

The reds and yellows aren't random, they're a countdown you can read.

Every fall it happens, one branch of a tree blazes red while another is still stubbornly green. It looks like the tree can't make up its mind.

The green is chlorophyll, the pigment trees use to make food. As days shorten and nights cool, trees stop producing it, and the green drains away to reveal what was hiding underneath.

The yellows and oranges were there all along, masked by green. The fiery reds are different, they're brand new pigments the tree actually builds as it shuts down for winter.

Branches that get more sun and colder nights turn first, which is why one tree can wear three seasons at once. It's not indecision, it's a chemical countdown to winter.