Abstract

To test the effects of liming (V500 kg/hectare) and the cutting of V1000 m 2 gaps on the formation of mushrooms in a yellow birch/sugar maple ( Acer saccharum Marsh.) forest, all mushrooms were collected and quantified from twelve 49 m 2 plots. The liming had a neutral or positive affect on the fruiting of most species, for example, certain Hygrophorus species. Ectomycorrhizal taxa (eg. Entoloma salmoneus, Lactarius rufus ) generally had decreased fruiting in the gaps whereas many non-mycorrhizal taxa were unaffected by the cuts. Species of Hebeloma and Laccaria however did not show any response to the treatments. The ectomycorrhizae on mature yellow birch were quantified using morphological and molecular analyses. Ectomycorrhizal abundance was compared to mushroom abundance and confirmed the lack of correlation between fruiting and mycorrhizal colonisation of yellow birch roots. The proportion of ectomycorrhizal ITS RFLPs matching mushroom RFLPs (34%) agreed with other studies. The matches included species of Cortinarius, Hebeloma, Laccaria and Russula . The data from seedlings from the same site showed that fungal taxa colonizing mature yellow birch had a higher diversity, due to a more even distribution. Some species of Hebeloma and Laccaria appeared to be more abundant on seedlings while species in the Russulaceae appeared to be more abundant on mature trees. These differences may reflect the importance of the fungal partners for the establishment and survival of yellow birch.