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Science of Fall Colors: About

Science of Fall Colors

Videos about Fall Colors

The Science of Fall Colors

For years, scientists have worked to understand the changes that occur in trees and shrubs during autumn. Although we don't know all the details, we do know enough to explain the basics to help you enjoy nature's multicolored display. Three factors influence autumn leaf color:

  • leaf pigments
  • length of night
  • weather

The timing of color changes and the onset of falling leaves is primarily regulated by the calendar as nights become longer. None of the other environmental influences – such as temperature, rainfall, food supply –  are as unvarying as the steadily increasing length of night during autumn palette.

A color palette needs pigments, and there are three types that are involved in autumn color:

  • Carotenoids: Produces yellow, orange, and brown colors in such things as corn, carrots, and daffodils, as well as rutabagas, buttercups, and bananas.
  • Anthocyanin: Gives color to such familiar things as cranberries, red apples, concord grapes, blueberries, cherries, strawberries, and plums. They are water soluble and appear in the watery liquid of leaf cells.
  • Chlorophyll: Gives leaves a basic green color. It is necessary for photosynthesis, the chemical reaction that enables plants to use sunlight to manufacture sugars for food.

Trees in the temperate zones store these sugars for the winter dormant period.

Both chlorophyll and carotenoids are present in the chloroplasts of leaf cells throughout the growing season. Most anthocyanins are produced in the autumn, in response to bright light and excess plants sugars within leaf cells. Continue reading from USDA Forest Service

From the Collection