Which tree species discussed has borer holes that can indicate defects extending to the heartwood, affecting its value?

• A. Sugar maple
• B. White ash
• C. Red oak
• D. White oak

Answer: (C)

Borer holes that reach the heartwood signal an internal defect serious enough to downgrade lumber value, because the heartwood is the portion that defines grade, appearance, and durability. In red oak, borer activity tends to penetrate deeper into the stem, and the resulting galleries and holes can extend into the heartwood. That means the wood’s structural integrity and visual quality are compromised, leading to a lower grade and reduced market value for high-end uses like furniture, veneer, and fine structural lumber. The other species listed either show more superficial damage or defects that don’t consistently indicate heartwood-level problems, so their presence doesn’t carry the same impact on value as it does with red oak.