A new , non-invasive method of determining internal decay in trees employ acoustic tomography, much similar to MRI or CAT scan used for humans and animals.

It is based on the principle that sound waves pass more quickly through solid wood than through decayed wood.

This multi-path acoustic tomography method uses 12 sensors that you can strap around the trunk to create a matrix of measurements. The computerized software program turns the data into a graphic diagram, which gives a pictorial view of what is happening inside the tree. This tells us if there are internal wounds or decay that can affect the stability of the tree.

Previous older method involves obtaining a core of wood by boring deep into the trunk and checking for disease by visual examination or microscopy.

Currently, only 3 companies make equipment for this test and they are all in Europe.

UW Tree specialist, Bruce Allison is only one of the
two arborists to use this technology in the US.

Read more in: 
Root Lessons
http://cals.wisc.edu/grow/