The cambium and its "zone" is a cell generator (reproductive tissue called growth meristem) that produces both the inner bark cells of the phloem and new living wood cells in the xylem.

The presence of sugars in the phloem drives an osmotic flow of water (blue arrows) from the adjacent xylem tissue (X, blue). This osmotic flow maintains elevated pressure in the phloem ...

One goes up... and one goes down. I was a college freshman in Botany 101 when I first learned about xylem and phloem, the two transport tissues which carry water and nutrients up and down a tree's ...