A preliminary study on the mycorrhizal associations of tree seedlings growing on old mine spoil at Avoca, Co. Wicklow

Ectomycorrhizas were identified on the root systems of nursery-grown lodgep ole Fine, Scots pine and silver birch planted onto a revegetation mine spoi l site at Avoca, Co. Wicklow. The revegetation site was divided into plots and imported mine spoil added to each plot was treated with various combina tions of lime, sludge and subsoil. The acidic, metalliferous mine spoil red uced seed germination of lodgepole pine and Scots pine, and nine-week-old s eedling; did not form mycorrhizas in a pot study. The main ectomycorrhizal fungus identified on the planted trees at the revegetation site and from Mi dleton Nursery (Co. Cork) was Humaria hemisphaerica (Wigg.: Fr.) Fuckel. In naturally-regenerated forests around the revegetation site, a different po pulation of ectomycorrhizas was found on trees of similar age, During autum n 1996 and 1997, fruit bodies of putative ectomycorrhizal fungi were collec ted in neighbouring forests. No fruit bodies were observed at the revegetat ion site. Inoculum cultured from fruiting bodies formed mycorrhizas and sti mulated the growth of lodgepole pine. It was concluded that inoculation of tree seedlings with selected ectomycorrhizal fungi could enhance their esta blishment and growth on mine spoil at Avoca.