As summer ends and autumn comes, the days get shorter and shorter. This is
how the trees "know" to begin getting ready for winter.
During winter, there is not enough light or water for photosynthesis. The
trees will rest, and royal reviewlive off the food they stored during the summer. They begin to shut down their
food-making factories. The green chlorophyll disappears from the leaves.As the bright green fade away we begin to see yellow and orange colors. Small amounts of these colors have been in
the leaves all along. We just can't see them in the summer, because they are
covered up by the green chlorophyll.
The bright reds and purples we see in leaves are made mostly in the fall. In
some trees, like maples, glucose is trapped in the leaves after photosynthesis
stops. Sunlight and the cool nights of autumn cause the leaves turn this
glucose into a red color.
The brown color of trees like oaks is made from wastes left in the leaves.
It is the combination of all these things that make the beautiful fall
foliage colors we enjoy each year.
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