Image source flickr
Autumn leaf color is a phenomenon that affects the normal green leaves of the deciduous trees and shrubs which they take on during the few weeks in the autumn season. The colors range from red to yellow and this phenomenon is commonly called fall colors/autumn colors and the term fall foliage means viewing the tree or forest while the leaves undergo the change.
In areas of the U.S. and Canada "leaf peeping" with tourism begins when the colors change and the onset of leaf falling in hopes of scheduling it as such, which has major contributions to economic activities in some of these areas. Makes perfect sense to me that leaves being this beautiful are: a show of color, can stimulate economy, and they give us so much, as nature does, and don't voice a single request for themselves in return.
In this leaf, the veins are still green while the other tissue is turning red and almost completely changed color.
Three factors influence autumn leaf: color-leaf pigments, length of night, and weather. The timing of color change and leaf fall are regulated by the calendar, with the increasing length of night.Image
None of the other environmental influences such as, temperature, rainfall, and food supply invariable as the steady increase length of night during autumn. As days grow shorter, and nights grow longer and cooler, biochemical processes in the leaf begin to paint the landscape with Nature's autumn palette.
A color palette needs pigments, and there are three types that are involved in autumn color:
Chlorophyll, gives leaves their basic green color. It's necessary for photosynthesis, the chemical reaction that enables plants to use sunlight to manufacture sugars for their food. Trees in the temperate zones store these sugars for their winter dormant period.
Carotenoids, produce yellow, orange, and brown colors in corn, carrots, and daffodils, as well as rutabagas, buttercups, and bananas.
Anthocyanins, gives color to cranberries, red apples, concord grapes, blueberries, cherries, strawberries, and plums. They're water soluble and appear in the watery liquid of leaf cells.
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 plant sugars within leaf cells.
During the growing season, chlorophyll is continually being produced and broken down and leaves appear green. As night length increases in the autumn, chlorophyll production slows down and then stops and eventually all the chlorophyll is destroyed. The carotenoids and anthocyanins that are present in the leaf are then unmasked and show their colors. The brown color of leaves is not the result of a pigment, but rather cell walls, which may be evident when no coloring pigment is visible.
What a show of brilliance it is and now you can say "Oh boy there goes the chlorophyll for this year!"
As the days get shorter and declining intensity of sunlight, leaves begin the processes leading up to their fall. The veins that carry fluids into and out of the leaf gradually close off as a layer of cells forms at the base of each leaf. These clogged veins trap sugars in the leaf and promote production of anthocyanins. Once this separation layer is complete and the connecting tissues are sealed off, the leaf is ready to fall.
What happens to the leaves when they fall? They decompose and restock the soil with nutrients. Fallen leaves also become food for numerous soil organisms vital in our ecosystem. In nature, nothing goes to waste!
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How do you celebrate the Miracle of fall foliage?
