Association between the anatomical features and the natural drying of young wood from hybrid Corymbia torelliana and Corymbia citriodora clones

Abstract

Wood anatomical relationships are essential for several industrial processes because they have straight influence on wood’s natural drying features. The objectives of the present study are to (i) assess and select appropriate hybrids of C. torelliana and C. citriodora clones in comparison to E. urophylla for wood cultivation based on wood drying rates and wood storage time reduction, (ii) to assess differences between C. torelliana x C. citriodora and Eucalyptus clones’ anatomical features and these features’ association with the natural wood drying process. Wood from four hybrids of Corymbia torelliana and Corymbia citriodora clones, and from one Eucalyptus urophylla clone, all of them at the age of 7 years, were assessed. Vessels, fibers and rays’ dimensions, wood basic density, heartwood, sapwood and bark contents, as well as heartwood and sapwood permeability were measured. Wood natural drying curves in logs were plotted by relating moisture content to drying days. The assessed drying parameters were initial moisture; time to rule out the free, bound and total water; water mass and wood basic density to water mass ratio; and rate of time needed to rule out free and bound water. Fibers, heartwood and sapwood dimensions were the features mostly distinguishing the hybrids of C. torelliana and C. citriodora clones from E. urophylla. Among the Corymbia clones, bark content and wood permeability were the variables allowing to separate the four clones into two groups. Both genera showed different anatomical heartwood and sapwood arrangementrs. It was more efficient drying wood from Corymbia clones, mainly due to their higher sapwood content, which enhances free water release and, consequently, makes the drying process faster. The anatomical arrangement of wood from hybrids of C. torelliana and C. citriodora clones favored the drying process; therefore, it can be employed by the forestry industry to select genotypes aimed at reducing wood drying and storage time in the field.