Decay and Sap-stain Fungi

Abstract

Most forms of decay and sap-stain in timber are caused by fungi that feed either on the wall tissue or cell contents of woody plants. It is important to distinguish between wood-rotting fungi, responsible for decay in timber, and those that feed on the cell contents, causing stains. The former consume constituents of the cell wall, and lead to the disintegration of woody tissue, whereas the latter remove only stored plant food material in the cell cavities, leaving the cellular structure intact. Wood-rotting fungi seriously weaken timber, ultimately rendering it valueless, whereas sap-stain fungi spoil the appearance of wood, but do not affect most strength properties. Sap-stain is not a preliminary stage of decay, but such stained timber, exposed to suitable conditions, may later be attacked by wood-rotting fungi.