Canadian Forest Service Publications

Re-establishment of ectomycorrhizae from refugia bordering regenerating Douglas-fir stands in Vancouver Island. 2009. Outerbridge, R.A.; Trofymow, J.A.; Lalumière, A. Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre, Victoria, BC. Information Report BC-X-418. 23 p.

Year: 2009

Available from: Pacific Forestry Centre

Catalog ID: 31201

Language: English

Series: Information Report (PFC - Victoria)

CFS Availability: Order paper copy (free), PDF (download)

Abstract

The objective of this study was to determine the influence of refugia on the rate of recovery of ectomycorrhizal (EM) diversity in clearcut and replanted Douglas-fir (Pseudotsuga menziesii) forests in British Columbia, Canada. Transects were established at two locations on southern Vancouver Island: Northwest Bay and Koksilah. The transects extended from 15 m inside the remaining 90(+)-year-old (mature) or old-growth Douglas-fir-dominated reference stands, to 45 m inside adjacent younger second-growth stands. The average ages of the latter were 6.0 years (regeneration), 27 years (sapling), 57 years (young forest), and 85+ years (mature forest). Diversity of EM was measured in soil cores sampled at five stations along each transect. A total of 83 EM taxa were found. The most common taxa were Cenococcum geophilum, "Pseudotsugaerhiza baculifera", Rhizopogon vinicolor and Piloderma fallax. Analyses of variance and covariance showed that species richness and proportion root colonization were drastically reduced with increasing distance from reference stands. The reduction was smaller for the transitions from reference stand to sapling stands, and insignificant in transitions to young or mature regenerating forest. Despite the full recovery of EM abundance to pre-harvest levels, which occurred approximately 55 years after replanting, differences in community composition remained after 60 years. Future studies should examine particular host-species and also mixed host-species scenarios that could accelerate the recovery process. Silvicultural practices aimed at promoting the re-establishment of EM fungi would include prompt replanting of harvested sites, using small cut-block sizes, minimal destruction of the forest floor, and green-tree retention.

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