The aim of ARB'UST project is to develop an ultrasonic device for parametric imaging of standing trees. The device is designed to perform both transmission and reflection measurements, used for quantitative tomographic imaging. It allows various automatic acquisitions since the angular position of sensors can be precisely adjusted. The electronics and associated configuration enable particularly the measurement of velocity and attenuation of the ultrasonic waves during their propagation within the medium. Two tomography experiments were conducted on a plane tree sample (before and after drilling a hole) and tomograms were calculated by the "Layer Stripping" algorithm. Our first results show that the artificial defect is detected.