Which tree tissue is primarily involved in growth in diameter?

Which tree tissue is primarily involved in growth in diameter?

• A. Xylem
• B. Cambium Layer
• C. Phloem
• D. Heartwood

Answer: (B)

Growth in diameter is driven by a lateral meristem called the cambium. This tissue sits between the older xylem on the inside and the phloem on the outside. Through continual cell division, the cambium adds new layers of secondary xylem inward and secondary phloem outward, thickening the stem or trunk over time. This process is known as secondary growth and is what makes a tree get wider as it ages. The tissues themselves—xylem and phloem—are produced by the cambium, not primarily responsible for girth increase on their own. Heartwood is the older, non-active wood that forms later and does not contribute to growth in diameter. So the cambium is the tissue that enables the tree to grow wider.

Growth in diameter is driven by a lateral meristem called the cambium. This tissue sits between the older xylem on the inside and the phloem on the outside. Through continual cell division, the cambium adds new layers of secondary xylem inward and secondary phloem outward, thickening the stem or trunk over time. This process is known as secondary growth and is what makes a tree get wider as it ages. The tissues themselves—xylem and phloem—are produced by the cambium, not primarily responsible for girth increase on their own. Heartwood is the older, non-active wood that forms later and does not contribute to growth in diameter. So the cambium is the tissue that enables the tree to grow wider.