Ectomycorrhizal community structure on western hemlock (Tsuga heterophylla) seedlings transplanted from forests into openings

Abstract

This study tested whether mature-forest ectomycorrhizal (ECM) communities could be maintained in forest openings on seedlings. Naturally regenerated western hemlock (Tsuga heterophylla (Raf.) Sarg.) seedlings were transplanted from mature forests into openings and the ECM fungal community was compared after 2 years with similar seedlings planted back into the forests or seedlings from openings planted back into openings. Fewer ECM morphotypes, lower average richness per seedling, and a steeper, less even species distribution curve were found, all of which suggest that the mature-forest ECM fungal community changed after transplanting forest seedlings into the openings. The increased abundance of pioneer fungi such as Thelephora terresteris suggested that many of the mature-forest ECM fungi were unable to maintain or continue root colonization in openings. Results suggest that many mature-forest ECM fungi require further stand development to maintain enough rooting density and hyphal contact to persist.Key words: ectomycorrhizal succession, disturbance, species-importance curves, multistage and late-stage fungi.