There
are two types of trees: deciduous and evergreen. In the
fall, the deciduous trees turn color and drop their leaves,
making autumn a beautiful season painted with red, orange
and yellow. The evergreen trees have “needles”
for leaves and remain green all year long, forming a picturesque
backdrop to the more brightly colored deciduous trees.
In the
Northern Hemisphere, we know this process begins in September…but
in the Southern Hemisphere, it begins in March, which is
the onset of autumn there!
Many
people wonder why the deciduous trees’ leaves change
color and drop off. First, it helps to remember that to
survive, trees need to: 1) gather sunlight, and 2) retain
moisture. The evergreen trees are better at retaining moisture,
because their needles are coated with wax, which keeps the
moisture in. But because the needles are small, they’re
not as efficient at gathering sunlight.
Since
the deciduous trees have larger leaves, they’re better
at gathering sunlight. But they’re not as efficient
at retaining moisture, so they drop their leaves as the
air gets colder. This keeps the tree from drying out, since
cold air can’t hold as much moisture as warm air.
It sounds simple, but there are many complex changes going
on!
One
thing that makes a difference is that the nights get longer
in the fall. A chemical called “chlorophyll”
gives leaves their green color. Chlorophyll also changes
sunlight into food for the trees during spring and summer
(this process is called “photosynthesis”). When
there is less sunlight because of longer nights in the fall,
the chlorophyll breaks down and the other colors (yellow,
orange, red) begin showing through. It turns out that these
colors were there all along, also helping with photosynthesis!
Their chemical names are “xanthophyll” (which
gives leaves the yellow color) and “carotene”
(which gives leaves the orange or red color).
The
spectacular bright purple red color that also shows in some
trees comes from a chemical called “anthocyanin”,
but this only happens when there are enough warm summer
days in the fall. If it’s too cloudy, not enough of
this chemical is produced to make the bright red fall colors.
This helps explain why some autumns might not seem as colorful
as others that you remember.
As we
enjoy the beauty of this autumn, we’ll also appreciate
nature’s amazing show going on “behind the scenes”!
Something’s
bruin…
Two
guys are out in the woods hiking. All of a sudden, a bear
starts chasing them. They climb a tree, but the bear starts
climbing up the tree after them. The first guy gets his
sneakers out of his knapsack and starts putting them on.
The second guy says, “What are you doing?” His
friend says, “I figure when the bear gets too close,
we’ll have to jump down and make a run for it.”
The second guy says, “Are you crazy? You can’t
outrun a bear!” The first guy says, “I don’t
have to outrun the bear. I only have to outrun you…”
GCPS
November 2008
The
1818 Rachel Hamlen homestead is looking for a new owner! Rachel’s
lovely vintage home on St. Albans Road would be the perfect
location and fit for a family, a cozy B&B, or an ice cream
parlor/café restaurant. Interested? Give Dave a call
at Hamlen’s (802) 868-4255.