An X-ray CT assessment of fungal growth in spruce, poplar and thermally-modified poplar

Abstract

ABSTRACT Poplar has been gaining attention as a potential material for use in engineered wood products (EWPs). However, poplar wood is not durable against fungal degradation, which is an important factor that needs to be investigated. Previous studies on degradation have mostly focused on evaluating mass loss (ML), while lacking information on the progress of degradation. In this study a recently developed non-destructive X-ray computed tomography (CT) technique was used to investigate the degradation progress within poplar, thermally modified (TM) poplar, and spruce during a 10-weeks fungal degradation experiment. The results showed that degradation led to a significant decrease in density, particularly after 15 days. Based on the X-ray CT scans, it was observed that spruce showed a higher mass loss at the end grain while poplar showed a homogeneous pattern throughout the entire block. Thermally modified poplar specimens were less degraded even at moist conditions. The density of the wood was found to affect the fungal susceptibility of both poplar and TM poplar: a higher density resulted in a lower mass loss of poplar. The use of X-ray CT scanning allowed for a detailed micro-level insight into fungal decay, which can potentially help in protecting poplar in future industrial use for constructions.