A novel method to correct for wood MOE ultrasonics and NIRS measurements on increment cores in Liquidambar styraciflua L

Key message Ultrasounds overestimate the MOE value. This paper analyses the causes of this difference and opens the perspective for a novel method allowing the calculation of the correct MOE from ultrasounds or NIRS measurements on cores. & Context Standardized methods for determining wood modulus of elasticity (MOE) are destructive and require many replicates. Other methods such as NIRS and ultrasound have been developed to characterize wood properties and overcome these constraints. & Aim The aim of this study was to compare the two MOE measurement methods (NIRS and ultrasound) applied to cores of wood taken from standing trees (Liquidambar styraciflua). & Methods MOE, measured by an acoustic method in standard samples (360×20×20 mm), was used as a reference. Then MOE was predicted by an NIRS model and determined using ultrasound in standard samples (360×20×20 mm), small samples (10×20×20 mm), and cores (15 mm in diameter). & Result MOE values determined by acoustic method on standard samples and by ultrasonic method on small samples were correlated (R2=0.72) and were not statistically different. The NIRS PLS regression yielded a model with R2 cv=0.80. The link between NIRS and ultrasound on cores was statistically significant (R2=0.68). & Conclusion The ultrasonic technique determines an apparent modulus enables comparative data analysis. This apparent modulus can be used for quantitative analysis if a corrective model is used. A correction formula to ultrasonic MOE was proposed in the case of a prismatic geometry. (Résumé d'auteur

USE OF A PORTABLE NEAR INFRARED SPECTROMETER FOR WOOD IDENTIFICATION OF FOUR DALBERGIA SPECIES FROM MADAGASCAR

This study focused on the use of Near InfraRed (NIR) Spectroscopy to address the lack of tools and skills for wood identification of Dalbergia species from Madagascar. Two sample sets of 41 wood blocks and 41 wood cores belonging to four Dalbergia species (D. abrahamii, D. chlorocarpa, D.greveana, and D. pervillei) were collected in the northern and western regions of Madagascar. Sapwood and heartwood NIR spectra were measured onwood at 12% moisture content by using a portable VIAVI MicroNIR 1700 spectrometer. Four discrimination models corresponding to sapwood and heartwood of the two sample forms were developed using Partial Least Square Discriminant Analysis (PLSDA). Good accuracy of 83.3% and 81.8% were obtained from the heartwood-based PLSDA models respectively for wood blocks and wood cores samples. All D. chlorocarpa samples were well-classified by the two models. Results highlighted the potential of portable NIR Spectroscopy as a helpful tool tosupport sustain- able management and trade of Madagascar’s Dalbergia species. Further studies are, however, needed for its operational use in identification routine