Lesson 1
A thin layer inside the bark
The cork cambium (also called phellogen) is a thin layer of dividing cells in the bark of trees and shrubs. Its cells are small, flat boxes lined up side by side in a row.
It forms when a stem gets too thick for its first thin skin. As the trunk keeps growing wider, new cork cambium layers can form deeper inside the bark.
Try thisLook at the branches of a cherry or birch tree. The little lines or dots on the bark are lenticels, breathing spots made by the cork cambium.
Lesson 2
Making a cork coat
Cork cambium cells divide and send new cells two ways:
- Outward, they make cork cells. Cork cells build waxy walls, then die. They form a waterproof coat that keeps water in and keeps many germs and insects out.
- Inward, they make a few living phelloderm cells.
Together, these layers are called the periderm. It is the outer bark that protects the tree.
Try thisPress Divide! on the 3D model, then press Cut open the cork.
Wow!The cork in bottle stoppers and bulletin boards comes from the bark of the cork oak tree. People can peel it off about every nine years without cutting the tree down!