Wood and charcoal identification of five species from the miscellaneous group known in Brazil as “Angelim” by Near-IR and wood anatomy

Abstract

Samples of wood sold as "angelim" in Brazil were studied. Disks from the trunks of Diplotropis purpurea, Hymenolobium petraeum, Parkia pendula, Vatairea guianensis and Vatairea paraensis were obtained from Mato Grosso state. Samples from pith to bark of each species were obtained, oriented in the three anatomical planes. Each sample was wrapped in aluminum foil and carbonized in a muffle furnace, with a final temperature of 450 °C and a heating rate of 1,66 °C min -1. The description of the anatomical elements of wood and charcoal samples followed the orientations of the International Association of Wood Anatomists, on the basis of 25 readings regarding frequency and tangential diameter of the vessels and height and width of the rays in micrometers. Infrared analyses were performed with a Bruker Tensor 37 spectrophotometer equipped with an integrating sphere and operating in reflectance mode, with resolution of 4 cm -1 and a spectral range of 10000-4000 cm -1. The wood and charcoal samples were placed on top of integrating sphere and one spectrum was obtained from each surface, resulting in six spectra for each physical sample. The results of anatomical analysis showed that the qualitative characteristics of wood remained in charcoal, so the method can be applied for species discrimination. When comparing cell dimensions, we observed different behavior between species in the same carbonization process in function of cell wall thickness and parenchyma distribution. In infrared analysis, pretreatment influenced adequate discrimination of "angelim" species in wood and charcoal. Linear discriminant analysis based on PCA scores and the region between 4000-6200 cm -1 was more efficient. Near infrared analysis can be used for differentiation of wood and charcoal of "angelim" species.

Effect of carbonization on wood anatomy of three Fabaceae species from an Araucaria forest stand in Southern Brazil

“…Reduction in vessel diameter after carbonization is related to anatomical features, such as the wall thickness of fibers and disposition of axial parenchyma cells, as well as processing conditions such as heating rate. These changes were also reported in other species, such as four Myrtaceae species (Stange et al 2018), in angelim species (Muñiz et al 2016) and other species from the Fabaceae family (Nisgoski et al 2012). Another factor that can influence vessel diameter is the possible change in circular shape of cells after carbonization (Gasson et al 2017).…”

“…O. Berg (60.3 %) and Myrcia retorta Cambess (50.7 %). Likewise, the influence of species characteristics on changes in vessel density after carbonization has also been reported in literature, such as for Anacardiaceae (Gonçalves and Scheel-Ybert 2016) and Fabaceae species (Muñiz et al 2016). The release of volatile matter and formation of some cracks and voids can also interfere in vessel density (Assis et al 2016).…”

“…Naudin, Cecropia glaziovii Snethl, Hyeronima alchorneoides Allemão and Pera glabrata (Schott) Baill. (Carvalho et al 2017); and angelim species (Muñiz et al 2016); besides 80 species described in an anthracology atlas (Scheel-Ybert and Gonçalves 2017).…”

The XyloTron: Flexible, Open-Source, Image-Based Macroscopic Field Identification of Wood Products

“…To move away from dependence on, or to complement, human expertise, various authors have advocated for computer vision based approaches to wood and charcoal identification. Several proof-of-concept systems have been reported, relying either on laboratory-acquired images (Khalid et al, 2008;Wang et al, 2013;Filho et al, 2014;Muniz et al, 2016;Barmpoutis et al, 2018;Andrade et al, 2019), or field-acquired cell phone images (Tang et al, 2018) that are relatively variable in terms of chromatic control, total magnification, spherical aberration, and other dataquality factors reviewed in Hermanson and Wiedenhoeft (2011), with two notable forays into controlling these factors for field imaging (Hermanson et al, 2019;Andrade et al, 2020). Computer vision based wood (Ravindran et al, 2018) and charcoal identification is appealing because it is affordable (Ravindran and Wiedenhoeft, 2020) and therefore scalable, operates on an accepted source of variability in wood, its anatomy, and for wood has demonstrated potential for real-world field deployment (Ravindran et al, 2019).…”

WorldForestID: Addressing the need for standardized wood reference collections to support authentication analysis technologies; a way forward for checking the origin and identity of traded timber

“…Near-Infrared Spectroscopy) is not currently being employed by WFID, but has been used to identify wood(Bergo et al, 2016;Braga et al, 2011;Pastore et al, 2011;Soares et al, 2017) and charcoal(Muñiz et al, 2016) of Swietenia macrophylla (mahogany), Dalbergia species (rosewoods) and various "Angelim" species(Diplotropis, Hymenolobium, Parkia, Vatairea) in Brazil.6.4 | Direct analysis in real-time time-of-flight mass spectrometryDirect analysis in real-time time-of-flight mass spectrometry (DART-TOFMS) is being used to great effect by the Office of Law Enforcement (OLE) National Fish and Wildlife Forensic Lab (NFWFL; Ashland, OR) and the United States Forest Service International Programs Wood Identification & Screening Center at Oregon State University (WISC; Corvallis, OR) to identify CITES-listed and commercially significant timbers imported into the US. The method is based on chemical fingerprinting of the small molecule profile, or chemotype, of heartwood.…”