PARLADÉ, JAVIER, ISABEL F. ALVAREZ, ANA RINCON & JOAN PERA.
IRTA, Departament de Patologia Vegetal, Ctra. Cabrils s/n, E-08348 Cabrils (Barcelona), SPAIN.
Selection of ectomycorrhizal fungi to improve field performance of trees used for reforestation in northern Spain has been carried out since 1987. A network of experimental plantations with different fungal strain-tree-site combinations has been established in both atlantic and mediterranean areas. To date, 30 field experiments are being monitored yearly to determine the effectiveness of the fungal strain to improve the outplanting performance of the inoculated plants compared to control non-inoculated plants. The tested combinations include nine fungal species (Laccaria bicolor, L. laccata, Melanogaster ambiguus, Pisolithus tinctorius, Rhizopogon colossus, R. luteolus, R. roseolus, R. subareolatus and Scleroderma verrucosum) and four tree species (Pinus pinaster, P. pinea, Pseudotsuga menziesii, and Quercus suber). Long-term results from five-year-old Douglas-fir plantations in atlantic areas indicate that L. bicolor, M. ambiguus, R. colossus, and R. subareolatus may estimulate plant growth in some sites. Preliminary data after one or two years in the field indicate that L. bicolor has a significant effect in improving first-year growth of Douglas-fir plants. In mediterranean plantations, it was detected a significant increase of growth in pine seedlings inoculated with R. roseolus. In most cases, fungal inoculation did not affect plant survival. In some plots, though, it was detected a significant survival improvement in plants inoculated with L. bicolor (in atlantic areas), and with R. luteolus or R. roseolus (in mediterranean areas).