So where do the beautiful colors of fall foliage come from?

The yellows and oranges are actually in the leaves all year round. These are the same pigments that give bananas their yellow and carrots their orange. During spring and summer, you don't see these colors because another pigment, the green chlorophyll, is so concentrated that it overwhelms the others. In the fall, the chlorophyll starts to break down. With less green, the yellows and oranges are unveiled.

With the reds and purples, it's a different story. They come from pigments that aren't even made in the leaves until the fall. Ideal conditions for their production include a dry late summer followed by sunny autumn days and cool nights.

These pigments account for the reds and purples found in sugar and red maples and red oaks. The leaves of a few trees, including dogwoods, are also usually red but could be yellow. Leaves of trees such as birches and hickories are always yellow in the fall, never red.