In the vicinity of large knots the grain is likely to be cross.

The defect is most serious where wood is subjected to flexure, as in beams.
_Spiral grain_ is a very common defect in a tree, and when excessive renders the timber valueless for use except in the round.

It is produced by the arrangement of the wood fibres in a spiral direction about the axis instead of exactly vertical.
Timber with spiral grain is also known as "torse wood." Spiral grain usually cannot be detected by casual inspection of a stick, since it does not show in the so-called visible grain of the wood, by which is commonly meant a sectional view of the annual rings of growth cut longitudinally.

It is accordingly very easy to allow spiral-grained material to pass inspection, thereby introducing an element of weakness in a structure.
There are methods for readily detecting spiral grain.

The simplest is that of splitting a small piece radially.