Qualitative and quantitative changes in anatomical characteristics of charcoal from Campomanesia xanthocarpa, Eugenia pyriformis, Myrcia retorta and Plinia peruviana were described to provide its correct discrimination and information’s to contribute to evaluations in illegal logging. The material came from Planalto Catarinense region, southern Brazil. For each species, three discs at diameter at breast height were collected from three randomly selected trees. All the disks were sectioned to obtain samples in different positions of the trunk (bark, intermediate and pith). Samples were 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. In species analyzed, growth rings are few distinct, delimitated by fiber regions; solitary vessel and axial parenchyma diffuse or diffuse-in-aggregate is predominant. The wood to charcoal conversion caused variation in the following characteristics: vessel diameters decreased varying from 21.1% in Myrcia retorta to 33.4% in Eugenia pyriformis, while the vessel frequency increased with values from 50.7% to 92.3% related to the same species; height and width of the rays showed reduction, however, Myrcia retorta presented ruptures in ray cells and dimensions increased; ray frequency increased from 3.9% in Eugenia pyriformis to 54.1% in Campomanesia xantocharpa. Qualitative characteristics of wood from studied species remained in charcoal after carbonization at 450 ºC, being possible to discriminate the material based on wood anatomy. In charcoal, vessels dimensions and frequency, after ray characteristics can be applied as first step in this Myrtaceae species distinction at forest control.
16 November 2019 in Wood Material Science & Engineering
Because of the species similarity and the need to differentiate wood of the Myrtaceae family, this study aimed to evaluate the potential of near-infrared spectroscopy for discrimination of wood and charcoal from Campomanesia xanthocarpa Berg, Eugenia pyriformis Cambess., Myrcia retorta Cambess. and Plinia peruviana (Poir.) Govaerts, native of the Araucaria Forest. For each evaluated species, three trees were collected and a disk at breast height was cut and divided into samples obtained in the region near the pith, intermediate and near the bark. For each sample, two spectra were obtained in each anatomical section (transversal, radial and tangential) in the region from 4000 to 10,000 cm−1. Results indicated the similarity of wood and charcoal spectra of all species, and principal component analysis (PCA) of raw data on samples showed little distinction of species, but second derivative pretreatment provided adequate discrimination. When evaluation was based on anatomical sections and position in trunk, for wood in all positions (near bark, intermediate, near pith) it was possible to separate species, but for charcoal some more samples dispersion were observed. Linear discriminant analysis corroborated the results of PCA. Near-infrared spectroscopy presented adequate results and the potential to help discriminate wood and charcoal of the four Myrtaceae species.
The aim of this study was to verify the potential of the colorimetric technique in the identification of some species marketed as "tauari" in the Brazilian Amazon. CIE L* a* b* parameters were applied to determine the colour of 35 wood samples from the main wood poles of the State of Para, Brazil, and the scientific collections of the Museu Paraense Emilio Goeldi (Walter A. Egler Collection) and Embrapa Amazônia Oriental. From each sample, data were obtained in the three wood surfaces: transversal, longitudinal tangential and longitudinal radial. The coordinate b*, which showed the yellow pigment, exerted greater weight in the color characterization of the 35 samples marketed as tauari, being more evident in the tangential and radial sections. In PCA, MGW wood samples showed considerably distinct color patterns in relation to PA and IAN samples, and the h and L* parameters provided better informations for distinguishing species from sample sources. The colorimetric technique can be used as an auxiliary tool in the identification of wood. However, the simultaneous use of colorimetry with the anatomical description of wood is suggested, given the complexity of the species-level separation in "tauari" group.