Growth in world demand for wood implies a search for new fast growing species with silvicultural potential, and in this scenario for native species such as Paricá . Thus, the objective of this study was determining the physical and mechanical wood properties of the Schizolobium amazonicum species (known as Paricá in Brazil). Trees were collected from commercial plantations located in the north of Brazil with ages of 5, 7, 9 and 11 years. Four logs from trees of each age in the longitudinal direction of the trees were obtained, and later a diametrical plank of each log was taken to manufacture the specimens which were used to evaluate some physical and mechanical properties of the wood. The basic density of Paricá was reduced in the basetop direction and no difference between the radial positions was observed, while the average basic density of this wood was characterized as low. The region close to the bark showed less longitudinal contraction and also greater homogeneity of this property along the trunk, while for tangential contraction the smallest variation was found in the region near the pith. Paricá wood contraction was characterized as low. Age influenced most of the mechanical properties, where logs from the base had the highest values of mechanical strength.

ResumoO objetivo deste trabalho foi avaliar a deformação residual longitudinal, o índice de rachaduras (de topo de toras e tábuas), o deslocamento da medula e os defeitos de secagem nas tábuas das espécies de Khaya ivorensis e Khaya senegalensis para a produção de madeira serrada. O material foi proveniente de um plantio experimental em Linhares, ES, Brasil, sendo utilizadas cinco árvores por espécie, com 19 anos de idade. Com as árvores em pé foi realizada a leitura da deformação residual longitudinal, utilizando o méto-do CIRAD -Forêt. Após o corte das árvores, os topos inferiores das toras da base foram fotografados para a mensuração das rachaduras e do deslocamento da medula. As rachaduras de topo e os empenamentos das tábuas também foram mensurados, após a secagem. No geral, não houve diferenças significativas nas médias de deformação residual longitudinal, índice de rachaduras de toras e tábuas e deslocamento da medula entre as espécies. Todavia, a espécie Khaya ivorensis apresentou as maiores dimensões de rachaduras de topo de toras e de tábuas, enquanto, as tábuas de Khaya senegalensis apresentaram os maiores empenamentos. Os índices das variáveis avaliadas não são elevados ao ponto de inviabilizar o uso e a qualidade das duas espécies de mogno africano para a produção de madeira serrada, sendo importante ponderar, principalmente, a forma e dimensões das árvores e os defeitos da madeira serrada em regiões mais próximas da medula e em idades mais jovens. Palavras-chave:Khaya, Deformação residual longitudinal, Rachaduras, Defeitos da madeira serrada. AbstractThe aim of this work was to evaluate the longitudinal residual strain, the index of splits (end of logs and boards), the displacement of the pith and the drying defects on the boards of the species of Khaya ivorensis and Khaya senegalensis for lumber production. The material comes from an experimental plantation in Linhares, ES, Brazil, with five trees per species being utilized, at age 19 years. The reading of the longitudinal residual strain using the method CIRAD -Forêt on standing trees was taken. After cutting of the trees, the end of logs was photographed for measurement of splits and displacement of the pith. The end splits and warping of the boards were also measured, after drying. Overall, there were not statistical differences in longitudinal residual strain, index split of logs and boards and displacement of the pith between species. However, Khaya ivorensis showed the larger dimensions of end split logs and boards, while, the boards of Khaya senegalensis had higher warping. The indexes of the variables are not high to the point of rendering unfeasible the use and the wood quality of the two species of African mahogany for the lumber production. It is important to consider, however, the shape and dimensions of trees and lumber defects in regions closest of the pith and at younger ages.Keywords: Khaya, Longitudinal residual strain, Splits, Lumber defects. INTRODUÇÃOOs plantios de mogno africano têm aumentado no Brasil nos últimos anos, com o...

ResumoAvaliou-se a influência das características anatômicas no desempenho da adesão da madeira de Vatairea sp., Paulownia sp., Aspidosperma populifolium e Tectona grandis. De pranchas Research, Society and Development, v. 9, n. 4, e31942727, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i4.2727 2 orientadas tangencialmente, foram produzidos corpos de prova para as análises anatômica e físico-mecânica da madeira. Os tratamentos foram juntas coladas de peças de mesmo plano de corte (radial e tangencial), avaliados quanto a resistência ao cisalhamento e falha na linha de cola. A madeira de angelim apresentou a maior massa específica aparente (0,74 g cm-3) e a madeira de kiri (0,34 g cm-3) o menor valor. A espécie peroba mica apresentou a maior resistência ao cisalhamento na linha de cola nas faces tangencial e radial. As características anatômicas com maior influência no processo de adesão da madeira foram as células de raios e as fibras, que exibiram as maiores correlações com a resistência ao cisalhamento na linha de cola.Palavras-chave: Adesivo; Linha de cola; Planos de corte; Resistência ao cisalhamento. AbstractThe aim of this study was to evaluate the influence of anatomical characteristics on the adhesion performance of Vatairea sp., Paulownia sp., Aspidosperma populifolium and Tectona grandis wood. Specimens for anatomical, physical and mechanical analyzes were produced from tangentially oriented boards. The treatments were joint glued from pieces of the same anatomical orientation (radial and tangential), evaluated for shear strength and glue line failure. The Vatairea sp wood had the highest specific gravity (0.74 g cm-3) and the Paulownia sp (0.34 g cm-3) wood was smaller. Aspidosperma populifolium species showed the highest shear strength in the glue line in the tangential and radial faces. The anatomical variables with higher influence on the wood adhesion process were pith ray cells and especially fibers that exhibit the greatest correlation with the shear strength of the glue line.

Variabilidade física e anatômica da madeira Avaliou-se a influência do espaçamento de plantio na variação radial da densidade aparente da madeira, através da densitometria de raios X, e das dimensões das fibras a partir de amostras do cerne periférico das baguetas da direção norte. Os dados foram submetidos à análise de variância, pelo teste F e as médias comparadas pelo teste de Tukey, quando a hipótese da anuidade era rejeitada. Houve maior crescimento em diâmetro e incremento médio anual em diâmetro (IMAD) para as árvores plantadas nos maiores espaçamentos (7x6 e 10x10 m). A densidade aparente média e dimensões das fibras da madeira de K. ivorensis não diferiram entre si em função do espaçamento de plantio aos cinco anos de idade. A densidade aparente da madeira teve correlação significativa com o DAP das árvores plantadas, no maior espaçamento (10x10 m), tendendo esta a diminuir conforme aumento do diâmetro a altura do peito (DAP) das árvores. Em todos os espaçamentos houve tendência comum de variação radial da densidade aparente da madeira, sendo menor próximo à medula e conforme o distanciamento da mesma tendeu ao aumento próximo a casca.Palavras-chave: mogno africano, crescimento em diâmetro, densidade da madeira. AbstractThe objective of this study was to evaluate the influence of spacing between trees in radial growth and quality of Khaya ivorensis wood, at 5 years of age. The plantations are located in the city of Pirapora, MG, Brazil. We assessed three planting densities: 5x5, 7x6 and 10x10 meters. We selected 10 trees in each spacing considering the north and south cardinal directions to remove the radial wood samples using nondestructive method, at 40 cm above the ground. We evaluated the influence of planting spacing in the radial variation of the apparent density of the wood through X-ray densitometry, and the size of the fibers from the peripheral heartwood of the north radial samples. Data were subjected to analysis of variance by F test and the means were compared by Tukey's test, when the null hypothesis was rejected. There was a higher diameter growth and mean annual increment (MAI) in diameter for the trees planted in greater spacings (7x6 and 10x10 m). The apparent average density and dimensions of K. ivorensis wood fibers did not differ with planting spacings at five years of age. The bulk density of the wood had significant correlation with DBH of trees planted in the greatest spacing (10x10 m), tending to decrease as the DBH of trees increase. In all spacings, there was a common trend of radial variation of the apparent density of the wood, being lower near the core and increasing as the distance from the same tended to increase, next to the bark.

Background Workers in the wood processing industry perform activities that demand great physical and ergonomic demands, which favors the emergence of inflammatory processes and in turn the occurrence of heat regions in the body, thus making it possible to assess the inflammatory level by means of temperature gradients. This study aimed to evaluate the use of thermography as an ergonomic analysis tool to identify regions with musculoskeletal overload in workers in a wood processing industry. Methods The study was conducted with nine workers in the central-west region of Brazil. The evaluations to obtain the thermographic images were carried out before the beginning of the workday, on Monday (day I) and on Friday (day II), in order to verify the overload regions in the accumulation of days worked. The thermal images were collected in an acclimatized room with controlled conditions where the participants remained with the upper part of their bodies bare for acclimatization, and then the lumbar and scapular regions were evaluated. The images were obtained using the FLUKE TI 400 Thermal Imager, with analysis using the SmartView software program to demarcate the body regions of interest. Results The mean temperature values obtained on day I did not significantly differ from the mean values obtained on day II. Qualitative analysis showed thermal patterns with high temperature at the same points on both evaluated days. Although the thermographic analysis performed in this study cannot provide definitive results, they generally helped to provide evidence for a more accurate diagnosis in the evaluated workers.