The electric resistance tomograph PiCUS TreeTronic is used in conjunction with the PiCUS Sonic Tomograph for tree risk assessment in order to get detailed information about the thickness of the residual walls and type of stage of a defect such as decay. The TreeTronic tomograms show in particular the early stages of decay and support in analyzing sonic tomograms. The combined application of the PiCUS Sonic Tomograph and the Treetronic is the most advanced imaging technology for tree inspections.