Diversity, production, and nutrient dynamics of fungal sporocarps on logs in an old-growth temperate rain forest, Olympic National Park, Washington

Abstract

Fungal sporocarps were sampled on 47 logs in six 0.1-ha plots in an old-growth Sitka spruce (Picea sitchensis (Bong.) Carr.) - western hemlock (Tsuga heterophylla (Raf.) Sarg.) forest in the Hoh River Valley, Olympic National Park, Washington, from October 1993 to May 1994. Log biomass averaged 205 Mg/ha and the surface area of plots occupied by logs was 9.8%. Most fungal fruiting occurred on decay class 3 logs, the most common type on a scale from 1 (least decayed) to 5 (most decayed). Eighty-two taxa of fleshy fungi (63 saprophytic, 18 mycorrhizal, and one pathogenic) and six taxa of large annual or perennial fungi occurred on logs. Most fungi were basidiomycetes. Highest fleshy sporocarp production occurred in fall (456 g/ha) rather than spring (40 g/ha). Ischnoderma resinosum had the highest annual production (88 g/ha). Concentrations of N, P, K, Ca, Mg, Mn, Na, Fe, Zn, Al, B, and Cu in fruiting bodies were determined. Lower N concentrations occurred in perennial fungi (0.45%) than mycorrhizal (4.33%) and fleshy saprophytic species (3.30%). Only a small fraction of the nutrient capital in the logs was exported to the forest floor in fungal sporophores.