UBC Theses and Dissertations
The effect of forest fertilization on the ectomycorrhizae of western hemlock (tsuga heterophylla) Kernaghan, Gavin
Granular urea (46% N) was applied at rates of 224 Kg N/ha and448 Kg N/ha to 4x4 m plots within a 20 yr. old stand composed almost exclusively of western hemlock [Tsuga heterophylla (Rafn.)Sarg.], located in the Mount Seymour Demonstration Forest, North Vancouver, British Columbia. Changes in the abundance of 10mycorrhizal types (Cenococcum geophilum Fr., Lactarius scrobiculatus (Scop.) ex. Fr., Mycelium radicis atrovirens Melin, Thelephora terrestris Fr., 3 Russula morphotypes, 2 unidentified basidiomycetes and a morphotype which formed no mantle) were assessed using random soil cores taken at 0, 1, 3, 6, and 11months after fertilization. On both treated and control plots, total number of fine roots and number of basidiomycetousmycorrhizae remained constant while Cenococcum mycorrhizae decreased and those lacking mantles increased. As the observed changes were independent of treatment level and pH, it is assumed that colonization was influenced by the sampling procedure, which involved the clearing of slash and the removal of forest floor material. Silvicultural practices which bring about physical changes to the forest floor may then have a greater impact on hemlock mycorrhizae than the chemical changes caused by forest fertilization.
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