Sonic Tomograph Testing is a non-invasive diagnostic test that is frequently used to assess the internal structure, condition and integrity of trees. This method allows arborists to detect potentially dangerous weaknesses in the core of the tree without having to damage its bark or structure. It is particularly useful for identifying rot or decay and the severity of it to determine whether a tree is in danger of failure.
How Sonic Tomography Works
The principle behind sonic tomography is based on how sound waves travel at different speeds through materials depending on their density and structure. In healthy trees the sound waves should travel throughout the structure of the trunk at a steady speed, while those that are experiencing decay, have cavities or internal damage will have the sound waves slow down or scatter entirely.
Arborists will place multiple sensors around the trunk of the tree or in the area of interest, such as the limb of the tree or it’s branches. They will then send several sound pulses throughout the tree, which are picked up by each of the sensors. The time it takes for each sound pulse to reach each sensor is then measured and processed by a program that generates a tomographic image of the tree’s internal structure. This image is what helps arborists identify flaws or weaknesses in the core of the tree.
Sonic Tomography works best on trees with relatively homogenous structures. Those with highly irregular growth patterns or dense, knotty wood are far more difficult to assess with this method.













Advantages of Sonic Tomography
The biggest advantage is that the process is entirely non-invasive. This means that the arborist does not need to risk removing the bark or surface of the tree in order to get a measurement from the tree, which greatly reduces the risks of pathogenic infections from taking root. Another great advantage of this practice is that it can detect flaws and decay well before it becomes visible on the surface of the tree itself, which allows for early treatment and action to be taken. Finally, its accuracy can precisely locate the area of damage and concern inside of a tree, such as pockets of decay and cavities. This level of accuracy can greatly help with assessing which course of action should be taken, especially if the tree is found around dense urban environments where it poses a risk of falling or damage to property or person.