Physical-mechanical characterization of two amazon woods coming from the second cutting cycle

Abstract

Due to changes in the Amazon forest dynamics after the first cutting cycle, non exploited species become dominant in the forest. The lack of technological knowledge makes it hard to commercialize these woods, making the understanding of their physical-mechanical properties a fundamental step to properly define their applications. This study aimed to characterize physically and mechanically the wood of Pseudopiptadenia psilostachya and Eschweilera ovata from the second cutting cycle of the Tapajós National Forest, intending to commercially promote and to identify usages for them, as well as to evaluate the viability of replacement of highly commercialized species. The tests were performed accordingly to the Brazilian standard NBR 7190. P. psilostachya, presented bulk density of 0.683 g.cm -3 , medium levels of shrinkage and anisotropy, as well as medium hardness (7366 N) and high strength on compression parallel to grain (71.63 MPa) and on static bending (103.9 MPa). It was generally superior to Euxylophora paraensis, but inferior when compared to Bagasssa guianensis and Apuleia leiocarpa, with possibilities to replace these three species. E. ovata, on the other hand, presented bulk density of 0.798 g.cm -3 , high shrinkage and anisotropy values, but high values for hardness (12089 N) and strength on compression parallel to grain (68.67 MPa) and on static bending (127.1 MPa). This species exhibited, in general, similarities with Mezilaurus itauba, although it is a little inferior in relation to Hymenaea sp. and Astronium lecointei. Both species, P. psilostachya and E. ovata fit in the highest strength class described on the Brazilian Standard NBR7190, C60. By means of the results found, it was concluded that although the species studied were unknown, they presented timber with enough quality to replace some Amazon timber species widely commercialized on both national and international market.An Acad Bras Cienc (2018) 90 (4) 3566BRUNO M. BALBONI et al.

WITHDRAWN: Technological Profile of Small-diameter Forest Species in a Managed Area in the Amazon

“…The correlation coe cient between the variables that make up the evaluated properties was highly signi cant (p < 0.001), and from a total of 78 correlations performed, 29.49% were classi ed as weak, while the others were moderate to strong (70.51%), with the majority being positive correlations, and an inverse (negative) relationship was observed for HCV (extracts, polyphenols, solubility in water, moisture and ash), moisture (HCV, BD, and MOR) and BD (cellulose). The most correlated properties were BD and MOR (12), followed by DAP and MOE (11), HCV and lignin (9), extractives and polyphenols (8), H and cellulose (7), and moisture and water solubility (6), and the ash content was the variable with the least correlation (4). The averages of chemical and physicomechanical properties (Table 4) were used to form groups (Fig.…”

Characterization of technological properties of matá-matá wood (Eschweilera coriacea [DC.] S.A. Mori, E. odora Poepp. [Miers] and E. truncata A.C. Sm.) by Near Infrared Spectroscopy

“…5). It is worth mentioning that the values predicted for the properties are in the range for high density Amazonian woods (INPA/CPPF 1991, Balboni et al 2018. Kollmann & Cotê Junior (1968) and Silveira et al (2013) state that the physical and mechanical properties depend on the moisture content of the wood, with this variable being inversely proportional to BD, HCV, MOE and MOR, i.e., the greater the water content, the greater the interrelation of hydroxyls with cellulose and hemicellulose molecules, increasing dimensional instability and defects in pieces of wood and reducing the energy potential, as well as the biological and mechanical resistance of the wood.…”

“…Knowledge of the mechanical properties of wood is essential for structural pur-poses. Balboni et al (2018) Yu et al (2020) compared the mechanical properties of Quercus mongolica (mongolian oak) wood using NIR modeling and observed values for breaking strength in the range of 120.00 to 200.00 MPa and resistance to elasticity from 12,000 to 18,000 MPa.…”

“…and Couratari stellata (Lecythidaceae), Bixa arborea (Bixaceae), Helicostylis pedunculata (Moraceae), Inga sp. and Tachigali chrysophylla (Fabaceae), among others (Balboni et al 2018, Freitas & Vasconcellos 2019.…”

“…The Amazon rainforest is considered one of the largest sources of tropical timber in the world, with a production at the end of 2014 of around 31 million m³ from the Brazilian states of Acre, Amazonas, Mato Grosso and Pará (OIMT 2015). This scenario would be satisfactory if this production originated from Sustainable Forest Management Programs that combine planned exploitation with legal, economic and ecological principles (Balboni et al 2018). At this level, 6000 botanical species with arboreal habit have already been cataloged; however, the commercial species are limited to a number of 100 (Garcia et al 2012).…”