Ectomycorrhizal mushroom response to partial cutting in a western hemlock - western redcedar forest

We examined epigeous ectomycorrhizal mushroom richness and productivity aft er partial cutting in a western hemlock (Tsuga heterophylla (Raf.) Sarg.) - western redcedar (Thuja plicata Donn ex D. Don in Lamb.) forest of northwe stern British Columbia. Mushrooms were collected throughout the fruiting se ason (July to October) for 3 years, starting 5 years after partial cutting, from plots with mesic soil conditions and residual basal areas ranging fro m 23 to 69 m(2)/ha for western hemlock and 0 to 26 m(2)/ha for western redc edar. Partial cutting had no apparent effect on mushroom phenology over the 3 years. Significant block interactions demonstrated that reductions in ba sal area of western hemlock could lead to positive, neutral, and negative r esponses in mushroom richness, biomass, and number of fruiting bodies. Thes e responses were related to stand structure and the potential differences i n tree vigour after partial cutting. In addition, there was weak evidence t hat western redcedar, a host for vesicular-arbuscular mycorrhiza, had a neg ative effect on average taxon richness. The study demonstrated that partial -cutting systems could allow some timber removal without necessarily reduci ng ectomycorrhizal mushroom communities.