Anatomy of a tree trunk.

Periderm consists of the cork cambium plus the layers of cork cells it produces.

Bark consists of tissues external to the vascular cambium, including secondary phloem and periderm.

The older layers of secondary xylem (heartwood) no longer transport water and minerals, leaving that function to the outer sapwood.

In temperate regions, the vascular cambium becomes dormant during winter. leaving annual rings.