Maiara Talgatti

Anatomia da madeira de Eucalyptus Benthamii Maiden & Cambage, espécie promissora para o setor de celulose no sul do Brasil

E investigada a anatomia microscopica da madeira de exemplares jovens de Eucalyptus benthamii Maiden & Cambage (Myrtaceae – Leptospermoideae) procedentes do estado do Rio Grande do Sul. Destacam-se os seguintes caracteres anatomicos: madeira composta por fibras, raios, parenquima axial e, em menores porcentagens, elementos vasculares e traqueides vasculares; vasos quase sempre solitarios, numerosos, em arranjo diagonal e porosidade difusa; parenquima paratraqueal vasicentrico e confluente; raios unisseriados, homogeneos e heterogeneos; e fibras libriformes. Mesmo sem caracteristicas singulares em sua estrutura, a presenca de elementos vasculares curtos, parenquima paratraqueal e fibras libriformes atestam um carater relativamente evoluido, comparado as Mirtaceas nativas. Apesar de jovens, as amostras analisadas recomendam a utilizacao da madeira de Eucalyptus benthamii para a industria de celulose e papel.

Tratamentos térmicos e secagem da madeira serrada de uva-do-Japão

The purpose of this study was ascertaining the influence of heat treatments in the drying rate and wood quality of Japanese raisin tree (Hovenia dulcis Thunb.). In order to do so, four trees with 25 years and average diameter at breast height of 39.5 cm and an average commercial height of 10 m, were harvested and transformed into samples of 40 x 130 x 500 mm (thickness x width x length), and classified as to the radial and tangential orientation of the material. The treatments consisted of heating in water by 12 and 24 h at 85 oC, and freezing by 12 and 24 h at - 18 oC. Then, the lumber was subjected to drying at 75 °C in a forced convection greenhouse until reach 12% of final moisture content. The freezing and heating treatments have proven to be influential on the drying rate, since the first accelerated the drying process, whereas the other one decreased. The freezing treatment by 24 h with samples oriented in the tangential direction showed higher drying rate compared with the others. The treatments presented to be not significant for the reduction of the contractions in the samples related to width, thickness and length. However, the volumetric contraction was significantly higher in samples heated in water. The Hovenia dulcis wood did not show top or surface cracks in any of the treatments used in this study.