Microwave frequency has the potential to assist and improve forest product industry in terms of quality and quantity. Consequently, it has been selected to perform non-destructive inspection on wood which is defected or contains resin internally. This paper describes an experiment to determine the relationship between the attenuation of microwave signals and the different diameters of the holes in tree trunks. This analysis can be used as a reference for an optimal setup for a new microwave tomography aimed at the inspection of valuable wood trunks.
