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AUTUMN AFLAME!
Each autumn the Northern Hemisphere has a display
of vivid colors from broad-leaved trees. What causes the changing
of colors? Why don’t the green leaves just drop off the trees as winter
sets in? Trees are very interesting food factories that take water
from the ground and carbon dioxide from the air. Add sunlight and
the tree changes the water and carbon dioxide into glucose. Photosynthesis
(putting together with light) is the term commonly used for turning
water and carbon dioxide into glucose. Glucose is used in trees for
food and as a building block for growth. Another chemical called chlorophyll
also assists in the photosynthesis process. Chlorophyll gives leave’s
their green color.
The autumn season ushers in shorter days and cooler
temperatures. With less daylight and a “snap” in the air, the process
of photosynthesis begins to stop. When photosynthesis stops there
is no more food production. Chlorophyll in the leaves begins to break
down, causing the green color to disappear. This allows the common
yellow to orange colors to become visible in the leaves. Other chemicals
in certain trees, such as the Dogwood and Sumac, form additional colors
like reds and purples. When glucose is trapped in a leaf it turns
red. Oak leaves are brown because of waste trapped in the leaves.
All of these colors are due to the mixing of various amounts of chlorophyll
residue and other pigments in the leaves. Other changes take effect
at the junction of the leaf and the tree. A layer of cells build up
and gradually sever the leaf from the tree. The tree seals the cut
and when the leaf is blown off a scar is left.
When nature puts on this type of display, tourists
want to know when is the best time to view it and where. Rule of thumb,
the best time is a clear, dry and cool autumn day. The best places
to view prime autumn colors are locations throughout New England,
Michigan and Wisconsin. This display does not last long, so there
are fall foliage hotlines (that’s right - autumn leaf hotlines). If
you are looking for the best days to view this spectacular display
of both nature and science then call either the U.S. Forest Service
at 1-800-354-4595 or the Wisconsin Division of Tourism at 1-800-432-8747.
All of this beauty is for us to behold and it is absolutely free!
- SharLeigh
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