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 ($$\uprho$$ ρ ) on stress-wave propagation ($$v$$ v ) was proved. A strong correlation between the dynamic moduli of elasticity ($${E}_{dyn}$$ E dyn ) and compressive strength ($$\upsigma$$ σ ) 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 $${E}_{dyn}$$ E dyn was less influenced than $$v$$ v by the heterogeneity of degraded wood. Therefore, $${E}_{dyn}$$ 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.

Do Sonic Tomography and Static Load Tests Yield Comparable Values of Load-Bearing Capacity?

“…It is based on the assumption that a tight and linear correlation exists between sound velocities depicted for a specific location in a tomogram and the actual properties of the wood fibers at that location. However, this correlation is typically quite low [20,21] because tomograms show estimates of apparent stress wave velocities between sensor positions on the periphery of the stem, presuming linear stress wave propagation. Actually, stress waves are more likely to travel around decayed sections rather than pass through them.…”

Using Acoustic Tomography to Model Wood Deterioration in Cedrelinga cateniformis Ducke in the Peruvian Amazon

“…Trees were classified into 10 cm diameter cl ses in all plantations. Between 3 and 13 individuals were evaluated, depending on the to number of trees included in each class [44]; 30,40,17,24,40,40,51,40, and 42 individu were evaluated in plots P1, P2, P3, P4, P5, P6, P7, and P8, respectively. The evaluatio were carried out between 40 and 60 cm above the ground because, as previous repo have indicated, in this species, rot mainly occurs in the basal section of the stems [45,4 Between 8 and 10 sensors were used, depending on the diameter of the shaft, i.e., mo than the 6 recommended by [47].…”

“…Tomographic images are essential in internal tree inspection [23]. The velocity of sound propagation is generally faster in healthy (more solid) wood than it is in degraded wood [24], although the acoustic properties of wood can also be affected by various factors such as age and phytosanitary status, as well as natural defects such as grain deviation, knots, and resin pockets.…”

“…In 2014, a demonstration in the Czech Republic showed non-invasive methods to be a promising tool for managing and protecting forest ecosystems [27]. In 2022, the use of the dynamic modulus of elasticity was found to improve the acoustic tomographic evaluation of standing trees, demonstrating that sound velocity is related to the mechanical parameters of wood [24]. The inspection of standing trees in China and Panama showed that acoustic tomography is an effective, non-invasive method for assessing internal decay, cavities, and structural integrity, even in irregularly shaped trees [4,28,29].…”