Why do trees have bark?
For grown-ups: the science
Bark is a tree's tough outer covering that protects it and helps it keep water inside.
Bark includes all tissues outside a tree's vascular cambium. The outer bark helps protect against physical injury, water loss, insects, and disease-causing organisms, while the inner bark carries sugary food from leaves to other parts of the tree. As trunks widen, outer bark often cracks or sloughs off and new tissues form beneath it.
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Transcript
Look at the tree trunk outside. Why does it wear that rough bark?
Bark is the tree's outside covering. It helps protect the living parts just under the surface.
The bark helps keep water inside the tree. It also makes it harder for bugs and germs to get in.
As a tree grows wider, its bark can crack and peel. New bark grows underneath to keep protecting the tree.
So bark is like a tree's tough outer coat. It helps the tree stay safe and healthy.