Application of tree tomography technique for defect detection in Picea abies

This research is to study the ultra sound wave parameters including slowness and attenuation of two Picea abies species as well as defects diagnosis (artificial) through tomography method. For this purpose, two roots of this species were prepared from Ojabit woods of Kelardasht zone in Mazandaran province. To perform the test, 15cm thickness discs were prepared from each root stock in three different states: with bark, without bark and defected (artificial hole). In order to do the measurement, ultra sound wave parameters were used. The measurement technique of this research was direct contact and 55 KHz wave frequency. The results showed that as the ultra sound proximate the wood pith, the wave slowness and attenuation coefficient increase and by moving from pith to the wood bark, both factors show reductions. In addition, the results of tomography showed that it is possible to diagnose the defects through measuring the attenuation factor. Although no impacts of bark existence were found in the pictures, the pictures that were taken by attenuated factors revealed defects and bark.