Comparison of communities of ectomycorrhizal fungi in old-growth and mature stands of Douglas-fir at two sites on southern Vancouver Island

An old-growth and a mature stand, each of fire origin and similar in drainage, slope, and exposure, were selected at each of two sites. Soil cores were collected in spring and fall for 2 years in each stand. Ectomycorrhizae were separated into types based on detailed examination of morphology and anatomy. All root tips were separated and counted. Sixty-nine morphological types were distinguished. Nineteen accounted for >1% of the 17 500 root tips examined, and 14 types were found in >5% of the 120 soil cores. Only three types were found in >20% of the cores. Total richness was approximately 100 fungi. Nine codominant mycosymbionts each colonized 2.8–24% of all tips and together colonized 67% of all tips. Cenococcum geophilum Fr. was the most abundant, followed by a Rhizopogon vinicolor Fr.-like species, an unidentified Piloderma-like species, Lactarius rubrilacteus Hesler & Smith, Piloderma fallax (Libert) Stalpers, and four unidentified species. Old-growth and mature stands had similar richness and diversity of ectomycorrhizal types. There was no evidence that any types were more abundant or frequent in one age-class than in the other.