Which term refers to groups of cells running from the center of the tree horizontally to the bark?

• A. Creep Characteristics
• B. Splits
• C. Orthotropic Behavior
• D. Wood Ray

Answer: (D)

Wood rays are defined as groups of cells that extend radially from the center of the tree toward the bark, running horizontally across the growth rings. These rays are typically made up of parenchyma cells and serve to store nutrients and transport substances across the wood. They form visible lines that connect the pith to the outer wood, which is why this term is used to describe them.

The other options refer to different concepts: creep characteristics describe time-dependent deformation under load, splits are cracks in the wood, and orthotropic behavior describes the directional dependence of wood’s mechanical properties. None of these describe the radial, cell-filled pathways that run from the center to the bark, which is exactly what a wood ray is.