What is the effect of fast growth on sapwood in walnut trees?

What is the effect of fast growth on sapwood in walnut trees?

• A. Slow growth trees tend to have a wide sapwood zone.
• B. They have no sapwood.
• C. Fast growth trees tend to have a wide sapwood zone.
• D. Sapwood width is unaffected by growth rate.

Answer: (C)

Growth rate directly shapes how much conductive tissue the tree keeps in the outer xylem. Sapwood is the living, water-conducting portion of the xylem that surrounds the heartwood. When growth is fast, cambial activity is high and more xylem is produced each year, so a larger portion of the xylem remains in the sapwood as the tree ages. In slower growth, heartwood forms earlier and more extensively, reducing the sapwood proportion and making it narrower. In walnut, this pattern means fast-growing trees tend to have a wider sapwood zone, reflecting more active, transitional xylem tissue.

Growth rate directly shapes how much conductive tissue the tree keeps in the outer xylem. Sapwood is the living, water-conducting portion of the xylem that surrounds the heartwood. When growth is fast, cambial activity is high and more xylem is produced each year, so a larger portion of the xylem remains in the sapwood as the tree ages. In slower growth, heartwood forms earlier and more extensively, reducing the sapwood proportion and making it narrower. In walnut, this pattern means fast-growing trees tend to have a wider sapwood zone, reflecting more active, transitional xylem tissue.