This paper aimed to study the variability on rigidity (MOE) and strength (MOR) properties in static bending and density (12 %) between juvenile and mature wood of 37-year-old Pinus taeda L. trees from Horto Florestal, Manduri, Sao Paulo, Brazil. In the first part of the experimental program, the juvenile, transition and mature wood zones were determined using anatomical analysis (tracheids length) according to the ABNT and IAWA codes. Results showed that juvenile wood zone occurs approximately up to the 18th growth ring. In the second part of the experimental setup, bending tests were performed with both juvenile and mature wood samples gathered in two distinct groups to obtain their modulus of rupture - MOR, modulus of elasticity -MOE and density (12%). Results showed that MOE and MOR of juvenile wood were always smaller and presented more variability, when compared to mature wood. Density at 12% showed the same tendency observed in the mechanical tests.
Juvenile wood; mature wood; modulus of rupture; modulus of elasticity; Pinus taeda L
