What happens to the heartwood in mature sugar maple?

• A. It dries out and reduces veneer quality.
• B. It becomes lighter in color.
• C. It can expand significantly further up the stem, affecting veneer quality.
• D. It stops growing.

Answer: (C)

In mature sugar maple, the heartwood forms and changes its extent as the tree ages. As newer rings are laid down and older sapwood transitions to heartwood, the heartwood zone can move upward along the stem, so you end up with heartwood occupying a larger portion of the trunk, even higher than in younger trees. This matters for veneer quality because heartwood typically has different density, extractives, and shrinkage behavior compared with sapwood. When the heartwood extends higher up the stem, these differences become more pronounced in the log, leading to greater drying stresses, more potential for warping or other defects during veneer production, and overall variability in veneer performance. So the key idea is that heartwood can expand significantly higher on the stem as the tree matures, and that shift can impact how well the wood veneers perform.