Date of Award

Fall 2012

Degree Type

Thesis

Degree Name

Master of Science (MSc)

Department

Geography and Earth Sciences

Supervisor

Altaf M. Arain

Co-Supervisor

Joe I. Boyce

Language

English

Committee Member

William A. Morris

Abstract

We evaluated 3-D imaging of coarse root structure and biomass using ground-penetrating radar (GPR). GPR surveys were conducted in a white pine forest in southern Ontario, Canada. GPR profiles were obtained across two test plots (6 and 17 m2 area), using 1-GHz GPR and a MEMS (micro-electro-mechanical systems) accelerometer. Test plot surveys evaluated the effects of micro-topography, soil moisture content, and root diameter and spacing. In addition, with the aid of the outcome of the control test plots two other plots (25 and 400 m2 area) were surveyed with varying line sample spacing to investigate the restraints on resolution brought about by line sampling density.

Accounting for antenna tilt is necessary to determine an accurate and more precise position of root mass. The antenna tilt was >45o pitch, >28o roll and up to 10o yaw due to surface micro-topography of the forest floor. Vector 3-D imaging enhanced the diffraction amplitude (15.5% increase) and centralized the position of the root. Radial surveys provided root continuity and produced better root imaging.

GPR largely underestimates coarse root biomass when a line spacing of 25 cm is used. However similar results are found with smaller line spacing (12.5 cm). A maximum line spacing of 10 cm provided continuous root structure and differentiation of roots spaced 10 cm apart and greater. A sampling line spacing of 5 cm and an inline sampling interval of 0.5 cm in low soil moisture conditions provided the detection of roots that were a minimum of 1.4 cm in diameter.

McMaster University Library


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