Ground-penetration radar detection of Root-mass in a Tree Groove in Southwestern Nigeria

Abstract

In this study, we present the results of a ground-penetrating radar (GPR) survey aimed at imaging the lateral root systems of a section of a tree groove lined by the Tectona Grandis (Teak) species. This was to set the basis for deploying a multi-frequency GPR system for the non-invasive monitoring of rootmass development and evaluation of plant development and health. The survey involved a single GPR Transect with a total length of 60.1 m established along the middle of a line of matured Teak trees. Data was collected at 250 MHz, 500 MHz and 1000 MHz, simultaneously using a wheel-triggered Utsi Trivue system. Data processing involved a dewow, static corrections, gain application and background removal. A root zone consisting of two layers was delineated and a total of 159 hyperbolae were interpreted as roots. The roots were limited to the shallow subsurface, the upper 1.1 m of a potential root zone 1.6 m deep. Imaged roots generally occur in clusters that create much disturbance of the otherwise continuous reflections in the root zone. Often, roots may be laterally offset from the location of tree bases on the Transect. We further identified a potential set of laterally migrating roots in a zone of undisturbed ground outside the main groove indicating the lateral reach of the usually shallow roots of the Teak tree. The results set the basis for further work in root-mass estimation and monitoring tree health within our team.