Using segmented linear regression to identify juvenile and mature wood of Tectona grandis

This study was carried out in order to identify and characterize the transition region between juvenile and mature wood of Tectona grandis L.f. with 17 years old, from the PU farm, located at Urutaí, Goiás, Brazil. The regions of juvenile and mature wood were characterized by anatomical studies - length of axial fibers using discs obtained at the DAP trees, following the recommendations of the International Association of Wood Anatomists. The fiber lengths were obtained from a diagnosis and image analysis equipment. A total of five slides were prepared for every 5 mm in the radial direction, and the lengths of six fibers were measured per slide. The results indicate a tendency of sharp and linear increase in fiber length, from the pith until 40 mm radius. The length between 40 mm and 60mm radius remains almost constant and, from this point, fiber length slightly increases until the bark. Therefore, for this species, when the tree is 17 years old, juvenile wood extends from the pith to 40 mm and the mature wood from 60 mm to the bark. Thus, for any use of teakwood, which includes areas of juvenile and mature wood, it is recommended further technological studies.