A sonic tomograph is an instrument used to study the internal structure of trees. It’s an ultrasound for trees. It is used to look for hollows, decay and cracks inside the trunk of a tree.
Sensors are placed around the tree and connected to the tomograph computer with a cable.
Then, a special sonic hammer is used to tap on each sensor in sequence. This produces soundwaves throughout the tree.
The sound wave paths are measured by the sensors. The sound waves will move differently if the wood is solid damaged, decayed or void. The computer will generate a map of the cross section of the tree.
It shows decay, cavities structural defects or cracks within the cross section area.
It tells us about remaining tree wall thickness and the percentage of solid, decayed, or damaged wood.
It works because solid wood is a better sound wave conductor than wood that is decayed or structurally damaged.