As the leaves of autumn take on various colors and
paint a spectacular picture across the countryside,
we often wonder, "Why do the leaves change color?"
No, it's not because a little elf
named Jack Frost flourished a paint brush or the
Great Bear, slain by celestial hunters, dripped
flood over the forests.
Chemical Changes
This natural phenomenon occurs when the chlorophyll
in the leaves breaks down. As the green color
disappears, the yellowish colors (masked by green
during the summer) become visible and give the
leaves part of their fall splendor.
Other chemical changes also take
place in the leaves and cause the formation of
additional pigments that vary from yellow to red to
blue. Some of these pigments cause the reddish and
purple colors in the leaves while others give the
brilliant orange and fiery reds to the trees.
The brownish and bronze colors are
caused by the mixing of varying amounts of the
pigments in the leaf in autumn.
Warm Days & Cool Nights
Warm, sunny days, followed by cool nights, with the
temperatures below 45 degrees F. are most favorable
for the formation of the brilliant red autumn
coloring. During the warm days, much sugar is
produced in the leaves but the cool nights prevent
it from moving from these leaves.
The trapped sugars cause the
formation of the red pigment which you see in the
maple, dogwood, red oak, sweetgum, sassafras, and
others.
The amount of color may vary from
tree to tree because of each one's direct exposure
to the sun. It even may vary on the same tree, for
different exposures will cause different colored
leaves.
Autumn is a colorful season when
we can enjoy spectacular scenery across the
countryside.
Visit Mary Emma Allen's web site
for more of her writing and information about her
books: http://homepage.fcgnetworks.net/jetent/mea;
E-mail: me.allen@juno.com. You'll also find more
articles at: www.valleyfun.com/maryemma.html |
