Health monitoring of a matured tree using ground penetrating radar -investigation of the tree root system and soil interaction

In this study, a demonstration of the ground penetrating radar (GPR) potential in the health monitoring of a matured tree has been given. The main objectives of the research were to provide an effective mapping of the tree roots as well as reliable simulation scenarios representing a variety of possible internal defects in terms of shape and formation. To these purposes, the soil around a 70-year-old fir tree, with a trunk circumference of 3.40 m and an average radius of 0.55 m, was investigated. A ground-coupled multi-frequency GPR system equipped with 600 MHz and 1600 MHz central frequency antennas was used for testing purposes. In addition to the above objective, finite-difference time-domain (FDTD) simulations of the electromagnetic field propagation through the cross-section of a trunk (consistent with the investigated fir tree) were carried out. A variety of defects representing cavities created due to decay were also simulated. The results from the simulations demonstrated significant potential for the interpretation of complex decay phenomena within the trunk.