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Leaves
Why do leaves change color in the fall?
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1 Reply
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The leaves on trees change color in the fall for a few key reasons:
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Decreased daylight: As the days get shorter in the fall, trees receive less sunlight. This triggers changes in the leaves that lead to the color transformation.
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Breakdown of chlorophyll: Chlorophyll is the green pigment in leaves that allows trees to absorb sunlight and undergo photosynthesis during the growing season. As daylight decreases in the fall, the trees stop producing chlorophyll, allowing other pigments like carotenoids and anthocyanins to become visible.
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Carotenoid exposure: Carotenoids are yellow, orange, and red pigments that are present in leaves year-round, but are normally masked by the green chlorophyll. As the chlorophyll breaks down, the carotenoids are exposed, leading to the yellow and orange fall foliage.
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Anthocyanin production: Some trees, like maples, produce additional red pigments called anthocyanins in the fall. These act as a sort of “sunscreen” for the leaves, protecting them as they prepare to drop. The production of anthocyanins results in the vibrant red colors seen in maple leaves.
So in summary, the combination of decreased daylight, the breakdown of green chlorophyll, and the exposure/production of other pigments all contribute to the beautiful autumn leaf displays we enjoy each fall season.
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