Which term describes how wood behaves differently along its three principal grain directions?

• A. Fatigue Characteristics
• B. Creep Characteristics
• C. Orthotropic Behavior
• D. Splits

Answer: (C)

Wood behaves differently along its three principal grain directions because it is orthotropic. This means its mechanical properties vary along three mutually perpendicular axes: longitudinal (along the grain), radial (from the center outward), and tangential (along the growth rings). This directional dependence explains why wood is typically much stiffer and stronger along the grain than across it, and why shrinkage and other properties differ between radial and tangential directions.

The other terms don’t describe this directional variation. Fatigue characteristics relate to failure under repeated loading, creep characteristics to time-dependent deformation under a sustained load, and splits describe a cracking failure mode, not the inherent directional properties of wood.