Determination of basic density and moisture content of merchantable loblolly pine logs by near infrared spectroscopy

The use of near infrared (NIR) diffuse reflectance spectroscopy for the estimation of basic density and moisture content of loblolly pine (Pinus taeda L.) logs was explored. A total of 219 wood disks representing the large and small ends of 146 merchantable logs 4.87 m in length, ranging in age from 13 years to 19 years, were analysed. NIR spectra were obtained from the transverse surface of the disks when the wood was green using a Foss XDS NIR System coupled with a Smart Probe Analyser. Each disk was divided into four quadrants and two spectra were collected per quadrant (one representing juvenile wood and one mature wood). NIR calibration models were fitted using pre-processed spectra with multiplicative scatter correction and the dimensionality of the models was kept constant for comparison purposes. Successful models based on an average of all spectra collected from both ends of the logs were obtained for basic density (R2c = 0.84) and moisture content (R2c = 0.85) using nine factors for both propert...