A
wood-decay fungus is a variety of
fungus that digests moist
wood, causing it to
rot. Some
species of wood-decay fungi attack dead wood, such as brown rot, and some, such as
Armillaria (honey fungus), are
parasitic and colonize living trees. Fungi that not only grow on wood but actually cause it to decay, are called
lignicolous fungi. Various lignicolous fungi consume wood in various ways; for example, some attack the
carbohydrates in wood and some others decay
lignin. The rate of decay of wooden materials in various climates can be estimated by empirical models.