spalting

Spalting is a form of natural coloration and patterning in wood caused by fungal activity. It results from fungi growing within dead or dying wood, producing pigments, contrast lines, or bleaching that give leaves, streaks, or zebra-like patterns. Spalted wood is prized in decorative woodworking and inlays for its distinctive aesthetics.

Mechanisms include pigment staining, where fungi deposit pigments that color the wood (green, black, brown); zone lines, which are narrow dark boundaries between competing fungal colonies; and bleaching or white-line patterns created by selective degradation of pigments and cell walls.

Fungal genera involved vary; the most famous example is Chlorociboria aeruginascens, which produces green wood stain used historically in inlay work; many other fungi produce a range of colors and dark lines. Spalting occurs naturally in many forest woods, especially hardwoods, and can develop as part of natural decay or after a tree is felled.

Use and practice: In natural settings, spalting is often seen in old logs and decaying timber. In woodworking, spalting is sometimes intentionally cultivated to create patterns by introducing fungal cultures under controlled conditions; practitioners consider safety and wood stability, as some fungi can produce toxins or continue to affect the wood if not properly managed.

Processing considerations: Spalted wood may be more brittle and less structurally stable; proper drying, stabilization, or sealing is recommended; finishing should account for irregular color and potential for continued fungal activity if not sealed. Spalted wood is commonly used for veneers, turning, and inlays, adding visual interest while preserving the natural wood grain.