Why Do Leaves Change Color?

Every autumn as the days get shorter and cooler, we see a beautiful variety of colors in leaves all around us. These color changes are caused by chemical processes inside the tree or plant. Different chemicals produce different colors and some trees have more of one chemical than another so that's why there is such a variety of colors.

During the summer, the chemical that makes the leaves green is strongest and so the green color covers up the other colors made by the weaker chemicals. It's during this time that the leaves act as food-making factories for the rest of the tree. This food-making process uses the chemical called chlorophyll and that's the chemical that makes the green color.

Other colors like orange and yellow are made by carotenes and xanthophyll pigments. Carotene is what gives carrots their orange color.

In the fall with less daylight and changes in the weather, the chlorophyll starts to break down and the other chemicals take over and their colors become visible. The leaves stop their food-making process.

As the leaves change color other things start happening, too. A special layer of cells forms at the point where the leaf attaches to the tree and it destroys the tissues that connect the leaf to the tree. The tree seals it off so by the time the leaf is blown away or just falls off, there is already a leaf scar on the tree.

Trees that have leaves that change color and fall off are called deciduous trees. That means they change with the seasons. Trees that have leaves that pretty much stay green all year round and don't lose their leaves with the seasons are called evergreens. Trees that make cones to distribute their seeds are called conifers. Most conifers are evergreens.

To learn more about leaves and their changing colors, see this Weather.com article.

To see a gallery of breathtaking autumn photos, GO HERE.

To see a gallery of cute pet fall photos, GO HERE.