Abstract A biological exposure method was developed that allows wood samples to be progressively removed for monitoring colonization and decay by basidiomycete fungi. Monitoring involves strength tests, determination of weight loss, and chemical analysis. To optimize the procedure, several variations of the method were tested using two species of brown-rot fungi ( Gloeophyllum trabeum and Oligoporus placentus ( Postia placenta)) and one white-rot species ( Trametes versicolor) against southern pine sapwood. The variations involved type of culture medium and exposure method. All variations enabled substantial and rapid decay. Specimens exposed to brown-rot fungi lost 80–100% strength and 25–40% weight after 12 weeks; the white-rot fungus was less effective, but nevertheless caused 20–40% loss in strength. For both brown- and white-rot fungi, strength loss exceeded weight loss. For brown-rot fungi, there was a direct relationship between strength loss and weight loss, suggesting a quantitative relationship between strength loss and chemical composition (hemicellulose sugars) during incipient decay of southern pine by these fungi.