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

Abstract

Yellow mycelia and cords of Piloderma fallax (Lib.) Stalp. were more frequently observed in old-growth stands than in younger managed stands of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). Piloderma fallax frequency and percent cover data were collected from 900 plots in three replicate stands 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. Presence of Piloderma fallax was related to the percent cover of coarse woody debris (CWD) in decay class 5. Piloderma fallax was approximately 2.5 times more likely to occur in a plot with CWD decay class 5 present than in plots without. The probability that it would occur in a plot increased by approximately 20% for every 10% increase in percent cover of CWD decay class 5. However, 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 differ among sampling times. Occurrence of Piloderma fallax may indicate suitable substrate for ectomycorrhizal fungi associated with CWD and may be important in forest management for the maintenance of biodiversity and old-growth components in young managed stands.Key words: Piloderma fallax, coarse woody debris, Pseudotsuga menziesii, forest management, ectomycorrhizal fungi, biodiversity.