Occurrence of Piloderma fallax in young, rotation-age, and old-growth stands of Douglas-fir (Pseudotsuga menziesii) in the Cascade Range of Oregon, USA

Yellow mycelia and cords of Piloderma fallax (Lib.) Stalp. were more freque ntly observed in old-growth stands than in younger managed stands of Dougla s-fir (Pseudotsuga menziesii (Mirb.) Franco). Piloderma fallax frequency an d percent cover data were collected from 900 plots in three replicate stand s in each of three forest age classes over 2 years in both spring and fall. Piloderma fallax is strongly associated with stand age; it occurred in 57% of plots in old-growth, 6% of rotation-age, and 1% of young stands. Presen ce of Piloderma fallax was related to the percent cover of coarse woody deb ris (CWD) in decay class 5. Piloderma fallax was approximately 2.5 times mo re likely to occur in a plot with CWD decay class 5 present than in plots w ithout. The probability that it would occur in a plot increased by approxim ately 20% for every 10% increase in percent cover of CWD decay class 5. How ever, the percent cover of Piloderma fallax was not strongly related to the percent cover of CWD in decay class 5. Frequency of occurrence did not dif fer among sampling times. Occurrence of Piloderma fallax may indicate suita ble substrate for ectomycorrhizal fungi associated with CWD and may be impo rtant in forest management for the maintenance of biodiversity and old-grow th components in young managed stands.