Near infrared spectroscopic and hyperspectral imaging of compression wood in Pinus radiata D. Don

Near infrared (NIR) spectroscopy has been used to predict the severity of compression wood in samples of radiata pine (P. radiata D. Don) using a subjective microscopic assessment of compression wood as the reference method. The calibration statistics are only moderate [R-2 = 0.84, r(2) = 0.6) which may be due to the subjectivity of the traditional method. Spatial resolution of compression wood in board cross-sections and discs from logs has been achieved using an improvised "NIR microscope" based on a Zeiss trinocular microscope and, more recently, using a NIR hyperspectral line camera. Compression wood was identifiable on the surface of discs across the continuum from normal wood to severe compression wood.