Drying of Wood: Principles and Practices

Both hardwoods and softwoods have cells (usu-

ally grouped into structures or tissues) that are

oriented horizontally in the radial direction and

which are called rays. The rays, composed of paren-

chyma with lignified cell walls or sclerenchyma, con-

nect various layers from pith to bark for storage and

transfer of food. In softwoods, rays are one-cell thick.

In hardwoods, they vary in size from one-cell wide

and a few cells high to more than 15-cell wide and

several centimeters high. Rays represent planes of

weakness along which drying checks develop easily.