Mechanical, physical and compositional effects of Meruliporia incrassata on Southern Yellow Pine

Abstract With the growing risk of fungal degradation in timber-framed structures from significant moisture intrusion events due to climate change, it is increasingly critical to develop mechanistic relationships between fungal degradation mechanisms and the strength of untreated wood components. While extensive work has been performed characterizing wood decay, no study has yet addressed the effects of Meruliporia incrassata on untreated Southern Yellow Pine. This seeks to address this knowledge gap by evaluating the effects of the common brown rot fungus on an ubiquitous building material in the southeast United States – Southern Yellow Pine. Properties of Southern Yellow Pine were evaluated at seven decay stages over the course of 12 weeks of exposure to M. incrassata . Changes in physical properties – mass, density, and moisture content – were measured at each stage. Changes in stiffness were characterized via ultrasonic pulse velocity testing, and thermogravimetric analysis was utilized to assess compositional changes. The study found rapid and significant losses in stiffness at decay stages as early as four-weeks. Hemicellulose and cellulose degradation occurred steadily throughout the decay period. These results can be utilized to develop a stronger understanding of the mechanical behavior of timber-framed structures in the United States degraded by brown rot.