Fungi decaying fallen stems of rimu (Dacrydium cupressinum, Podocarpaceae) in southern Westland, New Zealand

Abstract

The basidiomycete decay fungi present within stems of five rimu trees (Dacrydium cupressinum) uprooted 10 years earlier in southern Westland were investigated by isolating onto a selective culture medium.The most common fungi obtained were Armillaria novae-zelandiae and Ganoderma applanatum, sensu Wakef., while species isolated less frequently included Rigidoporus concrescens, Hypochnicium polonense and Irpex sp.There were few trends in overall percentage yields of basidiomycetes among trees, discs or radial depths, signifying that colonisation was uniform throughout stems, but A. novae-zelandiae was isolated more frequently from near the surface, while G. cf. applanatum had penetrated right to stem centres.Cultural pairing demonstrated that some vegetative compatibility groups of A. novae-zelandiae extended more than 4.5m, indicating invasion by mycelial growth along stems, while those of G. cf. applanatum were found in no more than one disc, implying multiple basidiospore colonisation.Results from this and previous studies in the central North Island suggest that these patterns may be typical for fallen rimu in podocarp-hardwood forests over much of New Zealand. © 2012 The Royal Society of New Zealand.