An efficient method to reduce grain angle influence on NIR spectra for predicting extractives content from heartwood stem cores of Toona. sinensis

Yanjie Li,Jun Liu,Xin Dong,Yang Sun,Jingmin Jiang

doi:10.1186/s13007-020-00623-3

Abstract

BackgroundA fast, reliable and non-destructive method is needed to qualify the extractives content (EC) in heartwood of T. sinensis cores in the breeding program for studying the genetic effect on EC. However, the influence of grain angle on near infrared (NIR) spectra prediction model for EC is unclear. In this study, NIR spectra were collected from both cross section and radial section of wood core samples in order to predict the EC in heartwood.ResultsThe effect of grain angle on calibration EC model was studied. Several different spectra pre-processing methods were implemented for calibration. It was found that standard normal variation (SNV) followed by 1st derivative yielded the best calibration result for T. sinensis EC. Grain angle had a significant influence on the predicted model for EC when using the whole NIR spectra. However, after testing a certain point of the prior variables for EC that were selected by the significant multivariate correlation (sMC), the influence of grain angle was significantly eliminated.ConclusionsIt is suggested that NIR spectroscopy is a promising method to predict EC in the solid wood without effecting grain angle.

Highlights

A fast, reliable and non-destructive method is needed to qualify the extractives content (EC) in heartwood of T. sinensis cores in the breeding program for studying the genetic effect on EC
Regardless of the pre-processing methods, wood core near infrared (NIR) spectra combined with partial least squares regression (PLS) model lead to a good result to discriminate wood longitudinal growth direction (0o) and cross section (90o)
The number of latent variables (LVs) in PLS models appears to need more in grain angle than in EC

Summary

Introduction

A fast, reliable and non-destructive method is needed to qualify the extractives content (EC) in heartwood of T. sinensis cores in the breeding program for studying the genetic effect on EC. The influence of grain angle on near infrared (NIR) spectra prediction model for EC is unclear. NIR spectra were collected from both cross section and radial section of wood core samples in order to predict the EC in heartwood. Trees produce various types of wood timber for industry and society construction. One of the most valuable and popular types of wood, especially in China, is the natural durable wood with splendid colours. Natural durable wood has self-preservation ability to survive biological decay [1, 2]. Natural durable wood with colours has been widely studied. The inner part of wood is called heartwood, and the outside of wood is recognized as sapwood.

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Discussion

Conclusion