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Confocal fluorescence microscopy was used to examine the spectral characteristics of lignin autofluorescence in secondary cell walls of normal and compression wood from Pinus radiata. Using UV excitation, fluorescence spectra of normal and compression wood sections showed significant differences, especially in the outer secondary cell wall of tracheids, with a shift in maxima from violet to blue wavelengths between normal and compression wood. A comparison of normal wood, mild and severe compression wood, showed that the wavelength shift was intermediate in the mild compression wood compared to the severe compression wood, thus offering the possibility of quantifying the severity by measuring ratios of fluorescence at violet and blue wavelengths. Fluorescence induced by blue light, rather than UV, was less well differentiated amongst wood types. Spectral deconvolution indicated the presence of a …