The ability of ectomycorrhizal fungi to link multiple plants and to function as a conduit for the movement of materials between plants has been demonstrated using autoradiographic laboratory studies; however, in the field this direct visual evidence is not available. In the field we must rely on indirect evidence for the role of ectomycorrhizal fungi in interplant nutrient transfer. Evidence from morphological, molecular and tracer studies of ectomycorrhizal plants in Douglas-fir and mixed Douglas-fir/birch forests in British Columbia will be reviewed. These data will be compared with studies from other systems to develop hypotheses about the presence, function and potential influence of ectomycorrhizal fungal linkages on plant community structure and diversity.

Key words: birch, common mycelial network, Douglas-fir, ectomycorrhiza, forestry