Qualitative and quantitative changes of beech wood degraded by wood-rotting basidiomycetes monitored by Fourier transform infrared spectroscopic methods and multivariate data analysis.

Beech wood (Fagus sylvatica L.) veneers were cultivated with white and brown rot fungi for up to 10 weeks. Fungal wood modification was traced with Fourier transform near infrared (FT-NIR) and Fourier transform mid infrared (FT-MIR) methods. Partial least square regression (PLSR) models to predict the total lignin content before and after fungal decay in the range between 17.0% and 26.6% were developed for FT-MIR transmission spectra as well as for FT-NIR reflectance spectra. Weight loss of the decayed samples between 0% and 38.2% could be estimated from the wood surface using individual PLSR models for white rot and brown rot fungi, and from a model including samples subjected to both degradation types.