Imaging tree root systems in situ

The study of root growth and development in soil has been intellectually and technically challenging. In response to concern about increasing levels of atmospheric carbon dioxide (CO2), resulting from increase in global energy use, the cycling of carbon has become the object of many intensive investigations.. Terrestrial ecosystems are a huge, natural biological scrubber for CO2 currently sequestering, directly from the atmosphere, about 22% of annual anthropogenic carbon emissions. It is assumed that a significant fraction of this carbon uptake goes into roots. Presently, there are no means by which root morphology, distribution, and mass can be measured without serious sampling artifacts that alter these properties. This is because the current methods are destructive and labor intensive. A non-invasive, imaging procedure for examining roots in situ would be a powerful tool quantifying subsurface storage, as well as for documenting changes in root structure. I Preliminary results using a high frequency, 1.5 Ghz, impulse Ground Penetrating Radar (GPR) for non-destructive imaging of tree root systems in situ are presented. Two 3D reconstructed images taking advantage of the polarization effect are used to assess root morphology and dimensions. The constraints, limitations, and potential solutions for using GPR for tree root systems imaging and analysis are discussed.