Fungal and arboreal biomass in a western Oregon Douglas-fir ecosystem: distribution patterns and turnover

Abstract

The allocation of biomass and the turnover time of various components were measured from August 1976 to August 1977 in a young, second-growth Douglas-fir stand in the Oregon Coast Range. Allocation of biomass among the tree components was 14 732 kg foliage ha−1, 30 455 kg branches ha−1, 212 941 kg boles ha−1, 49 289 kg nonmycorrhizal roots ha−1, and 15 015 kg host portion of mycorrhizae ha−1. Biomass allocation of fungal components was 10 009 kg mycorrhizal mantles ha−1, 2785 kg Cenococcumgeophilum sclerotia ha−1, 65 kg sporocarps ha−1, 369 kg litter hyphae ha−1, and 6666 kg soil hyphae ha−1. The forest floor was composed of 6970 kg fine (<2 mm) litter ha−1, 6564 kg coarse (2–25 mm) litter ha−1, and 5500 kg log (>25 mm) litter ha−1. Soil organic matter (<0.494 mm) was 87 600 kg ha−1. Total annual stand throughput was 30 324 kg ha−1, excluding soil organic matter throughput. Of this total, 50.5% was accounted for by fungal throughput, 39.5% by tree throughput, and 10.0% by forest floor throughput.