Today there is an increasing demand for wood protection systems which are based on low environmental impact technologies. The aim of this study was to improve a method for investigating furfurylated Pinus radiata, both in terms of the furfuryl alcohol polymerisation process in the wood cell wall and the detection of initial signs of brown rot degradation. It is an established theory today that brown rot degradation starts with lignin modification in the outermost part of the secondary cell wall and the combined middle lamella. We adapted a method (cellular UV microspectrophotometry, UMSP) which enables direct imaging of the lignin distribution and modification within individual cell wall layers. Furfurylated P. radiata, incubated with Postia placenta, were scanned with monochromatic UV-light at 280 nm. The results showed that USMP is a promising method to study furfurylated wood and early fungal degradation damages in the cell wall of furfurylated wood.