How wood behaves

Grain, movement, seasoning, and the parts of the tree — the properties that decide a joint.

• GrainThe direction wood fibres run through a piece of timber, and the pattern that direction leaves on a cut surface.
• Wood movementThe ongoing shrinking and swelling of dried timber as its moisture content changes, which joints and panels must be built to allow for.
• SeasoningThe process of drying timber, by air or in a heated kiln, until its fibres shrink to a moisture level fit for use.
• HeartwoodThe older, inner wood of a tree, usually a different colour from the sapwood around it and often more resistant to decay.
• SapwoodThe younger, outer band of wood around a tree's heartwood, whose proportion affects durability and how well preservative soaks in.