Why Tree Bark Has Lines

Trees wear coats. Bark is the coat. It protects the tree.

Young trees have smooth coats. Older trees have lines. The lines are cracks.

Trees grow outward. The inside grows. The outside does not grow.

The coat gets tight. It splits. Lines form.

Different trees have different lines. Oak trees have deep lines. Birch trees have paper lines. Pine trees have thick plates.

Lines help the tree. Fire cannot hurt thick bark easily. Insects stay outside. Water stays inside.

Look at a tree today. Count the lines with your finger.

Do you see lines on every tree?