XVI International Botanical Congess

Seedlings were colonized at a lower level (predominantly by Cenococcum geophilum) in versus out of Rhododendron maximum thickets (RmT), but correlation with reduction in seedling growth was weak. Although some individual species were significantly more predominant, overall, ectomycorrhizal sporocarp communities were similar in versus out of RmT. Diffuse light intensity (50%), light fleck frequency and duration, soil moisture content (20%), organic matter, and N pools and mineralization rates, were all lower in versus out of RmT. Seed rain and seed banks were similar in versus out of RmT. Allelopathy by RmT substrates was not observed. Interaction between reduced light availability and mycorrhizal colonization is discussed in relation to seedling suppression in RmT.