Which wood-decay type is known for breaking down lignin and leaving pale, fibrous wood? The answer is white rot. White-rot fungi digest lignin, the complex polymer that helps make woody plant cell walls rigid and resistant to decay.
As lignin is removed, the remaining cellulose-rich material can appear pale, bleached, soft, and fibrous. White rot commonly also breaks down cellulose and hemicellulose, so affected wood loses both strength and mass. The pale residue gives the decay type its name and distinguishes it from brown rot, which leaves a darker, brittle, cubically cracked residue rich in lignin.
White-rot fungi use oxidative enzymes such as lignin peroxidase, manganese peroxidase, versatile peroxidase, and laccases. These enzymes attack lignin’s chemically resistant structure, opening carbon sources that many other decomposers cannot easily reach.
The distinction is useful but not absolute: decay strategies form a biological continuum, and some fungi traditionally classified as brown rot can modify limited amounts of lignin. White rot remains the standard answer because lignin decomposition and pale, fibrous wood are its defining textbook clues.