Non-destructive characterization of maritime pine sawn timber dielectric anisotropy by means of GPR

The dielectric response of timber to electrical fields is influenced by many factors, one of the most important being the internal structure of the wood. Thus the anisotropy of the wood should be taken into account when the ground-penetrating radar (GPR) technique is used to explore the properties of timber. The work carried out analyzes, by means of a GPR with a 1.6 GHz antenna, the dielectric behavior of Maritime Pine timber according to the direction of the electrical field with respect to the grain. After the acquisition process, the propagation velocities, amplitudes, and spectra variations were compared for all the studied grain directions. Significant differences were found between these parameters when the field was propagated in a parallel direction compared with perpendicular to the grain. However, when the field was propagated in various perpendicular directions to the grain (radial & tangential) the studied parameters were not found to differ greatly.