Fungal communities in attached ash (Fraxinus excelsior) twigs

The composition (including an association analysis) and three-dimensional structure of fungal communities in dead, attached ash (Fraxinus excelsior) twigs were analysed. Community composition was similar at all three contrasting sites studied, the most constant species being Phomopsis platanoidis, Sp. 12 (an unidentified sterile mycelial form), Libertella fraxinea, Peniophora lycii, Fusarium lateritium and an Acremonium sp. This composition differed strongly from that in attached ash branches, where P. lycii was the only representative from the above list frequently isolated.

Five distinctive types of community structure were detected. These were interpreted as representing different temporal stages in the development of communities. Putative primary colonizers (P. platanoidis, Sp. 12 and F. lateritium) were present in the bark of living healthy twigs and invaded the wood when the twigs were dying. Secondary colonizers (all other species) were established later, presumably via air-dispersed spores, and gradually replaced the primary colonizers by active or passive means. Eventually one or other of the secondary colonizers (frequently P. lycii) became dominant.