James Chambers at TMA, Paul Melarange at ThinkTrees, and Ian Barnes at Barnes Associates are concerned about poor Sonic Tomography leading to unnecessary tree felling or damaging crown reduction tree work.
To help those of you who get Sonic Tomography carried out by Picus, Arbotom, or ArborSonic, they've published this guide of what to look out for.
Sonic Tomography - Decay Detection Considerations
This is such a useful collaborative project, we'll forgive them for using the Safe word in it :-)
Here's a nice example of where a 'red line' is a 'red flag' in a tomogram.
t/R = 0.3 makes no sense.
t/R = 0.3 makes even less sense when the cross section is asymmetric.
Or when and the decay is off centre.