Here's a breakdown:

* Bark is a protective layer that covers the trunk, branches, and roots of a tree.

* It's made up of two main layers:

* Outer bark (also called cork cambium): This is the dead, outermost layer of bark that protects the tree from damage, insects, and disease. It also helps regulate temperature and water loss.

* Inner bark (also called phloem): This is the living layer of bark that transports sugars and other nutrients from the leaves to the rest of the tree.

So, while the outer layer is technically called cork cambium, it's often referred to simply as bark.