Use of Visible and Near-Infrared Spectroscopy for Discrimination of Eucalypt Species by Examination of Solid Samples

Abstract

Eucalypt species have high importance in the forestry sector in Brazil. The wood has wide range of uses, including pulp, charcoal, plywood panels and treated boards. However, eucalypt species are hard to identify in lumber, which can cause problems in industrial use. So, the aim of this study was to combine visible and near-infrared spectroscopy to discriminate wood samples of two Corymbia spp. and five Eucalyptus spp. Visible spectroscopy was performed according to the CIELab standard. The data were analysed using descriptive statistics and regression analysis. Near-infrared analyses were based on ASTM E1655-05. The data were analysed with the Unscrambler X chemometric program, in the raw form and after pre-processing with second derivative of Savitzky-Golay. Visible and near-infrared spectroscopy can be successfully applied to separate Eucalyptus and Corymbia species. In the visible spectroscopic analyses, it was possible to separate the wood samples into two colour groups, i.e. red/rose and grey/yellow/brown. In the near-infrared spectra it was possible to discriminate samples, and three groups associated with density of the species were formed. Both techniques were appropriate to distinguish species and their industrial use might solve practical problems.

Wood Colorimetry of Native Species of Myrtaceae From a Araucaria Forest

“…Thus, the need to use alternative characteristics that allow the correct identification of the wood is evident, such as those revealed through colorimetry, DNA and near-infrared spectroscopy (MORI et al, 2005;NUNES et al, 2009;OLIVEIRA et al, 2015). Therefore, the wood color is one of the most important macroscopic aspects for the species differentiation (MORI et al, 2005) and its potential has already been evaluated by several studies (NISGOSKI et al, 2017;GONÇALVES, 2001;SILVA et al, 2015, SILVA et al, 2017. Nevertheless, studies on colorimetry are still necessary to identify the particularities of each species based on characteristics such as growth rings, vessels, rays, parenchyma type, extractive content, among others MORINONIO, 2016).…”

Applying colorimetry for wood differentiation of fabaceae species grown in southern Brazil

“…Among the species (Figure 6A), original spectra of Muellera campestris was separated from the others, and this distinction was confirmed by the ellipse grouping, which was the result of light-yellow color of wood. In some eucalypt species, Nisgoski et al (2017) also found a distinction of samples in PCA of reflectance spectra in function of wood color.…”

“…Maderas-Cienc Tecnol 24(2022):16, 1-20 Ahead of Print: Accepted Authors Version 4 Thus, the use of colorimeters or spectrophotometers can be an alternative, since the evaluation is fast and needs little training. Some studies have shown the potential of this technique to evaluate wood modifications after thermal treatment (Cademartori et al 2013), to characterize Eucalyptus wood (Mori et al 2005), and to distinguish Eucalyptus and Pinus species (Nisgoski et al 2017;Amorim et al 2013) and Myrtaceae species (Vieira et al 2019b), among others. However, for adequate species discrimination, it is necessary to have a database that includes all heterogeneous characteristics of wood, since color is influenced by various factors, like radial position in the trunk and anatomical section evaluated.…”

Colorimetry as a tool for description of some wood species marketed as “tauari” in Brazilian Amazon

“…Colorimetric parameters also are influenced by natural degradation or thermal treatment of wood (Torres et al 2012, Cademartori et al 2013. The application of wood colorimetric parameters in species discrimination or grouping is scarce; some examples are the separation of eucalyptus (Martins et al 2015, Nisgoski et al 2017) and some tropical species in Brazil (Silva et al 2017). Zhao (2013) proposed a wood species classification using color surface data and related good results in intra and inter specific variations.…”