Voices of Spencer Creek
Aren't you glad your skin stretches when you grow? If you were a tree it might not. Did you ever look at the bark of a tree? Was it full of wrinkles and creases? Just this year I noticed for the first time how those wrinkles are made.
A tree grows at the outside of its trunk. Just under the protective bark or skin is a growing layer, called the cambium layer, which works something like our blood vessels.
In the summer the roots send water and minerals up through it to the leaves. The leaf-factories use the sun as power to make tree food out of what the roots send up. This food is sent back through the cambium layer to be stored just under the bark in the new or sap wood. The next spring it will be used to grow more leaves.
The bark was the right size to fit the tree before all that summer growth. In a good growing season when there's plenty of rain and sun the bark has to separate a little here and there to make room for what's happening beneath it.
If you look in the fall you can see the whitish or yellow growth layer at the bottom of the cracks in the bark on some kinds of trees, especially evergreens. After a few weeks the tree forms a kind of scab or skin in the crack to protect the exposed growth area. Then it looks like the rest of the bark.
Next year when the tree food is stored again the bark will split some more, probably in the same cracks. After many years the bark on some kinds of trees gets to be six inches thick with great wrinkles in it.
People are lucky that Nature's plan for us includes skin that stretches. Who would want six-inch skin with such wrinkles?
This story was originally printed in the Mennonite Family magazine, Purpose.
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