Why Do Leaves Change Color in Autumn?

Trees need food to grow. They make food using sunlight, water, and air. This process is called photosynthesis. A green substance called chlorophyll helps trees make this food. Chlorophyll is why most leaves are green during spring and summer.

As autumn arrives, days get shorter. There is less sunlight. Trees sense the change. They know winter is coming. Winter is cold and dry. It is hard for trees to keep their leaves alive during this time.

Trees start to close down their food factories. They stop making new chlorophyll. As the green chlorophyll fades away, other colors appear. These colors were inside the leaves all along! They were just hidden by the strong green color.

Yellow and orange pigments, called carotenoids, show up. Red and purple colors, called anthocyanins, are made from leftover sugars in the leaf. These colors make the forest look beautiful.

When the leaves turn brown, they are dead. The tree has already pulled all the useful nutrients back into its branches and roots. The tree saves this energy to survive the winter. Soon, the leaves fall to the ground. The tree goes to sleep until spring.

Nature has a clever way of preparing for the cold. Leaves change color to signal that the tree is resting. It is a cycle of life.

What is your favorite color of autumn leaves?