Which term describes separations of wood fibers between growth rings, parallel to the grain?

• A. Knot
• B. Wood Ray
• C. Shakes
• D. Splits

Answer: (C)

Shakes are separations of wood fibers that occur between annual growth rings and run parallel to the grain. They form when internal stresses, including those from drying or rapid changes in moisture, cause the wood to crack along the grain between rings. This type of crack weakens the board and is categorized by where it occurs: ring shakes between rings and radial shakes along the grain. This differs from a knot, which is a branch that has become part of the wood; a wood ray, a normal anatomical feature running across rings, and splits, which are cracks that extend in different orientations or through the wood in other ways.