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Tree Cores for Root Bores: Exploring Tree Rooting Behaviour in Bituminous Soils

  • Author / Creator
    La Fleche, Marc Alexandre
  • Surface mining in the Athabasca Oil Sands region has disturbed approximately 895 km2 of boreal forest, all of which will need to be reclaimed to a state that is both representative of, and as productive of the surrounding boreal forest. However, much remains to be understood regarding the effects of different reclamation practices on restoring forests on mined landscapes. Reclamation practices, though varied, can involve the construction of landforms using overburden materials such as lean oil sand (LOS, sand containing concentrations < 8% hydrocarbons) with a layer of appropriate soil medium placed on top. While some early studies suggest that there may be negative effects of LOS on tree growth, forests have been growing on natural shallow bitumen deposits since the last ice age. The goal of this thesis is to explore whether using dendrochemical methods can allow us to better understand the relationship between tree rooting behaviour and shallow bitumen. Soil, soil pore water, and tree cores were taken from sites with natural shallow bitumen deposits and analyzed for trace metals enriched in bitumen (vanadium, nickel, molybdenum, and rhenium). Samples were also collected from sites without bitumen present. Significantly elevated concentrations of Ni were observed in trees growing on shallow bitumen deposits. Vanadium was also elevated in trees on bituminous sites though not significantly so. Molybdenum displayed the opposite trend and decreased in trees on bituminous sites. A baseline survey was also conducted on a reclaimed landform constructed using LOS to establish a proper reference against which future research can compare. My thesis establishes that with strong analytical methods and good reference conditions, dendrochemistry is a feasible methodology for monitoring root growth in bituminous soils with V and Ni acting as potential signal elements. This possibility presents reclamation practitioners and researchers with a useful tool to monitor plant growth across both constructed landforms and natural landscapes along with strong data against which to compare future values.

  • Subjects / Keywords
  • Graduation date
    Fall 2019
  • Type of Item
    Thesis
  • Degree
    Master of Science
  • DOI
    https://doi.org/10.7939/r3-x0pb-8d35
  • License
    Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.