Acoustic tomography outputs in comparison to the properties of degraded wood in beech trees

Abstract

The interpretation of the outputs of acoustic tomography is often altered by different physical and mechanical parameters. Detailed information on the relationships between static mechanical properties and dynamic parameters of intact and degraded green wood can improve the results of this device-supported method used for tree stability assessment. This research presents a graphic and statistic comparison of acoustic tomography outputs with the laboratory assessed material parameters. The analysis was based on the relationship between the dynamic and static mechanical parameters of four cross-sections from two living tree stems. The occurrence of seven white and soft rot fungi was taken into consideration. The influence of density (uprho) on stress-wave propagation (v) was proved. A strong correlation between the dynamic moduli of elasticity ({E}_{dyn}) and compressive strength (upsigma) is reported. A higher heterogeneity of wood degradation among the cross-section can lead to an underestimation of the defect during AT assessment. The dynamic modulus of elasticity {E}_{dyn} was less influenced than v by the heterogeneity of degraded wood. Therefore, {E}_{dyn} can be used to form a better interpretation of acoustic tomography assessment of standing beech trees. Due to the complexity of the topic, further investigation of previously mentioned relationships is still needed.