Henry Kock was an interpretive horticulturist for two decades at the University of Guelph's arboretum, where he founded the Elm Recovery Project.
Paul Aird is a forest scientist and professor of forest conservation policy at the University of Toronto.
John Ambrose served as curator of the University of Guelph's arboretum, and curator of botany and manager of horticulture at the Toronto Zoo.
Gerald Waldron is the author of three books and many popular articles and scientific papers on trees.