This overall objective of this project is to investigate the role of ectomycorrhizae (ECM) and common mycorrhizal networks (CMN) in facilitating Douglas-fir regeneration in the interior of British Columbia. It is comprised of three studies being conducted by four graduate students supervised primarily by Dr. Suzanne Simard, Dr. Melanie Jones, and Dr. Dan Durall. In the first study, PhD student François Teste is conducting a series of experiments in the IDF zone (1) to examine the influence of advance regeneration size on Douglas-fir seed and seedling regeneration, and (2) to examine the influence of green tree distance on Douglas-fir seedling performance, and (3) to determine whether importance of the CMN to Douglas-fir establishment increases with site disturbance. In Francois? first experiment, Douglas-fir was planted and seeded near established Douglas-fir advance regeneration of different sizes, and in his second experiment, at different proximities to pole-sized trees. In the third experiment, a range of organic matter removal treatments were applied in the border areas of the Long Term Site Productivity study sites near Kamloops (Berch 2000), and advance regeneration were transplanted to these treatments to serve as EM inoculum sources to seedlings being planted in 2005. In the second study, PhD student Leanne Philip completed a draft of her PhD thesis. The objectives of her project were: (4) to determine the importance of CMN pathways to carbon transfer between Douglas-fir and paper birch, and (5) to determine whether the magnitude and direction of carbon transfer changes with tree phenology. Her study helps address the importance of CMNs to Douglas-fir under competitive stress from paper birch in wetter Douglas-fir ecosystems. In the third study, two Masters students, Brendan Twieg and Denise Brooks, are examining the influences of paper birch refuge trees on the ECM of Douglas-fir in stands of different ages. The study is integrated with Studies 1 and 2 through quantification of the potential for paper birch and Douglas-fir to share ECM (identified at the morphological and molecular levels), and therefore from a CMN. Brendan and Denise?s studies will determine (6) how long it takes for the ECM fungal community found in mixed forests to re-establish on clearcuts (addressing ecosystem recovery and whether CMN formation potential increases with time), and (7) whether the Douglas-fir ECM fungi on clearcuts are better adapted to those sites than are forest fungi.
Philip, Leanne Jane, Simard, Suzanne W.; Jones, Melanie D.. 2005. Ectomycorrhizae and networks: their role in facilitating Douglas-fir regeneration under water, site and climatic stresses. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2005MR385