The use of three geophysical methods for 3D images of total root volume of soil in urban environments

How does the tree root system develop in the subsoil? This question is important to the development and urban planning disciplines, especially when the trees occur near building foundations and underground utilities. This interest is based on the potential for buildings to suffer subsidence or structural damage from nearby trees. The inspection of both the extension of the tree roots and the degree of decay in wood are still undertaken using classical single-point and destructive methods. However, as pointed out by several authors, geophysical methods provide an alternative method of studying root architecture in a non-invasive fashion. In this paper, three geophysical methods were applied to produce 3D images of total root volume in the soil in an urban environment. The three geophysical methods used were ground-penetrating radar, electrical-resistivity tomography, and seismic refraction tomography. Each of the geophysical methods alone is able to isolate root system but cannot resolve the ring structures.