Wood grain refers to the orientation of wood fibers along which axis?

• A. Perpendicular to grain
• B. Crosswise only
• C. Oriented along the long axis
• D. Random orientation

Answer: (C)

Wood grain describes the direction in which wood fibers are aligned in a piece of wood. In most lumber, these fibers run lengthwise, along the long axis of the piece. This longitudinal alignment is why the wood is strongest and stiffest in that direction and why cutting, planing, and bending respond the way they do. When you see the grain, it appears to run along the length because the cells themselves are oriented that way.

If the grain were perpendicular to the length, you’d be talking about the crosswise or across-grain direction, which changes the wood’s strength and how it behaves under load. The idea that grain is random doesn’t fit typical lumber, where a consistent long-axis orientation dominates.