Assessment of anatomical characteristics of wood – bark, sapwood and heartwood – in hardwoods species of Galician oaks by image processing: Relationship with age
Our work on the physical properties of wood in hardwood species, Quercus robur L., Q. petraea (Matts) Liebl., and Q. pyrenaica Willd., for study its use in cooperage, began with the proportion appraisal of bark, sapwood, and heartwood, and its relationship with age, to know and assess the variation thereof in the Galician oaks. To properly perform our study, it was necessary to fell several Quercus trees within the study area (Galicia, NW Spain). In total, 45 trees were selected in 15 different stands located in the Galician provinces of Lugo and Ourense, from which we obtained 45 slices of wood at 60 cm height on the tree trunk. There are many anatomical differences between hardwood and softwood species; however wood parts of a tree system are common to both. The analysis of different proportions of bark, sapwood, and heartwood made it possible to reveal: i) the rapid growth of Quercus pyrenaica gives rise to the formation of large proportion of heartwood in a few years; ii) Quercus petraea has the largest proportion of heartwood, but the studied trees are older and their growth is slower than the other species; iii) Quercus robur has an intermediate growth between the other two species. Therefore, our aim was to carry out a complete description of these parts of the wood, later, in upcoming work estimate their physical properties for use in cooperage industry.