The annual production of xylem by cambium is called?

• A. Branch Collar
• B. Sapwood
• C. Growth rings
• D. Rays

Answer: (C)

Growth rings form when the cambium adds a new layer of secondary xylem each growing season. Each year’s layer, with its characteristic early wood (lighter, airy) and late wood (darker, denser) if conditions vary, creates a visible ring in cross-section. Those yearly layers are the growth rings, representing the annual production of xylem by the cambium and providing clues about the tree’s age and past growing conditions. Branch collar is a structural feature at a branch base, sapwood is the younger conductive wood, and rays are radial groups of cells for storage and lateral transport—not the annual xylem production.