Tree Anatomy: Cambium & Sapwood

The cambium and sapwood represent the active growth engine and primary water transport infrastructure positioned directly beneath the protective outer bark of a tree's trunk.

The vascular cambium is a microscopic, single-cell layer of actively dividing meristematic tissue that encircles the entire tree. Each growing season, the cambium divides to produce new cells; those produced toward the outside become the living phloem (inner bark), while those produced toward the inside become the xylem, or sapwood.

The sapwood forms the outer structural ring of the wood and consists of active, tube-like vascular tissues. Its primary function is to act as a powerful plumbing system, transporting vast quantities of water and dissolved mineral nutrients absorbed by the roots upward to the canopy to fuel photosynthesis. Because these cells are fluid-filled and actively growing, the sapwood layer is also utilised by the tree to store vital starch reserves.

Understanding the location and vulnerability of the cambium and sapwood is critical in forestry; if a tree is girdled (a ring of bark and cambium stripped entirely around the trunk), the transport of water and sugars is completely severed, causing the tree to die.
cv. Heartwood