ABSTRACT Currently, there is a little and sparse information about how the growing conditions influence the spatial variation of wood along the stem. Thus, the aim of this study was to compile the knowledge from literature in a manuscript for better understanding to what extent the growing conditions influence the spatial variation of wood properties in Eucalyptus plantations. The wood characteristics may present variations in their properties and can be caused by both genetic and environmental factors. However, how genetic and environmental factor acts on wood variation along the trunk is still unclear. Another point is that even with new genetic breeding programs, the mechanical properties of wood have not been considered in these programs, since the selection of new material is always based on the growing rate, cellulose and lignin content and wood density.

ABSTRACT This study aimed to evaluate the behavior of samples of juvenile and mature Eucalyptus cloeziana wood when subjected to the drying process, and the influence of the anatomy on that behavior. In order to do this, saturated specimens from this woods measuring 10 × 5 × 1 cm were subjected to drastic drying at 100 °C, where the drying rates and the end check scores in different steps of the process were obtained. The fibers and vessels morphology, initial moisture and basic density were analyzed to help understanding the data obtained in the drying test. The juvenile wood presented 26% higher drying rate and 21% smaller drying time, also 53% higher end check score. Smaller fibers length and fibers wall thickness, higher vessels frequency and smaller vessels diameter were associated with higher total drying rate and water adsorption, as well as with the higher end check score.

RESUMO Para diversos usos da madeira, como na produção de celulose e papel e do carvão vegetal, a presença da casca é indesejável, podendo comprometer a produção. Desta forma, este trabalho teve como objetivo avaliar a influência de diferentes espaçamentos de plantio nas propriedades da casca de um clone de Eucalyptus grandis x E. camaldulensis aos sete anos de idade em cinco diferentes espaçamentos de plantio. Os discos de madeira foram retirados das árvores nas posições 0, 25, 50, 75 e 100% da altura comercial. Foram feitas análises da espessura, densidade, poder calorífico superior e minerais da casca. Não houve diferenças significativas entre os tratamentos para o poder calorífico e para a espessura da casca. Para a densidade básica da casca, os maiores valores foram encontrados nas árvores plantadas nos maiores espaçamentos e considerando os teores de minerais, houve diferença significativa apenas para P, Mn e Zn.

ABSTRACT For several wood uses, such as pulp, paper and charcoal, the presence of the bark is undesirable, compromising production. Thus, this study aimed to evaluate the influence of different plant spacings on the properties of the bark of a clone of Eucalyptus grandis x E. camaldulensis at seven years of age at five different plant spacings. The wood discs were removed from the trees at 0, 25, 50, 75 and 100% of the commercial height; then we performed thickness, basic density, gross calorific value and mineral content analysis of bark. There were no significant differences among treatments for the bark gross calorific value and thickness. For the bark basic density, the highest values were found in trees planted in wider plant spacings and considering the mineral content, there was a significant difference only for P, Mn and Zn.