Drying defects

Drying defects are the most common form of degrade in timber, next to natural problems such as knots (Desch and Dinwoodie, 1996). There are two broad categories of drying defects (some defects involve both causes):

• defects that arise due to the shrinkage anisotropy. This leads to warping: cupping, bowing, twisting, spring and diamonding.
• defects that arise due to uneven drying. This leads to the rupture of the wood tissue: checks (surface, end and internal), end splits, honey-combing and case-hardening. Another such defect is collapse, often seen as a corrugation, or "washboarding" of the wood surface (Innes, 1996). Collapse is a defect that results from the physical flattening of fibres, above the fibre saturation point (thus not a form of shrinkage anisotropy).

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Incoming search terms:

• timber drying quality and case hardening and moisture content gradient