The study centred on 6 plantations of various ages in Bizkaia, firstly studying the wealth of epigeous fungi (based on sporocarps) as well as of hypogeous fungi (as ectomycorrhizals). Over a three-year period of sampling, 111 high-value species of macromycetes were studied; being grouped in 7 orders (Agaricales 60%, Russulas 18%, Boletals 14%, Polyporals 4%, Pezizales 2%, Cantharelles 1% and Phalalles 1%). The mature plantations, apart from showing a greater specific wealth, have proved to be more homogenous amongst each other than the non-mature ones. As regards ectomycorrhizals, 90 morphotypes have been described: 6 of these were identified at a species level; 1 was ascribed to a hitherto unknown morphotype and 7 to a genus. As regards the number of morphotypes, no differences were observed between mature and non-mature plantations. Winter turned out to be the season with the greatest number of morphotypes and of ectomycorrhizals types, followed by the autumn. Also, the infective potential of the soils of the plantations was evaluated and it was observed that plantlings of 1 or 2 saps can be mycorrhized by the inoculum present in both mature and non-mature plantations. Regarding the selection of mycorrhizal species for their use in afforestation, it was observed that Scleroderma areolatum and S. citrinum are species with great potential that significantly enhance the quality of the plant produced in the nursery and earmarked for afforestation.