Changes and effects of a natural fire on ectomycorrhizal inoculum potential of soil in a Pinus halepensis forest

A typically mediterranean forest of Pinus halepensis was studied. During two years following fruiting fungal species, the number of sclerotia in soil, and the percentages and types of mycorrhizas present were determined. In burned stands ascomycetes were typical carbonicolous while basidiomycetes were strongly reduced. The sclerotia extracted from soils were mainly Cenococcum. The number of sclerotia in burned stands was greater than in unburned stands. Seven types of mycorrhizas were recognized in Pinus halepensis root systems from bioassays: Cenococcum, E-strain, Rhizopogon, Suillus, Tuber, Xerocomus, and one non-identified. Nearly 100% of the roots were colonized by mycorrhizal fungi. Ectendomycorrhizas represented 50-90% of the total number. The predominant type is ectendomycorrhizas formed by ascomycetes included in the E-strain group. (C) 1997 Elsevier Science B.V.