Fungi from Canadian coniferous forest soils

The fungus flora from four pine forest soils was investigated. Qualitative studies used a soil-washing method, whereas quantitative investigations were performed using a direct observation technique. Results indicate that the fungus populations on litter and humus from all four forest soils are fairly similar, with Cladosporium herbarum, Aureobasidium pullulans, Alternaria sp., and various members of the order Sphaeropsidales being common in the litter, and Trichoderma and Penicillium species increasing in frequency in the F and H layers. The fungi isolated from the mineral soil horizons were more varied in nature, but certain genera seemed to be found frequently; these included Mortierella, Chrysosporium, Oidiodendron, Paecilomyces, Cylindrocarpon, Torulomyces, and sterile dark fungi.A detailed investigation of a Pinus strobus forest at St. Williams, Ontario, revealed no distinct seasonal patterns in the relative frequencies of the species of fungi.Quantitative studies showed that, in all soils, mycelial content decreased with depth from the humus. A comparison of the four sites showed a wide variation in fungal mycelium, varying from 30 m/g dry soil under Pinus strobus (in the A1 horizon) to 1540 m/g under P. contorta during May. Seasonal data from the P. strobus forest indicate a peak in mycelial content during August.