Abstract:The spread of four decaying fungi through mechanical injuries of sound healthy pedunculate oak (Quercus robur L.) trees was examined. They are Stereum hirsutum (two different geographical strains), Chondrostereum purpureum, Stereum rugosum and Xylobolus frustulatus. Vital standing trees of pedunculate oak were artificially inoculated with mycelia (in vivo) at the locality of lowland forests of Slatina (Compartment 31, Section D) by using Pressler drill. The occurrence of dying-back symptoms, the rate of mycelium spread through the stem, the speed of wound callusing and the occurrence of fruiting bodies or decay symptoms were observed. All the tested fungi spread faster in longitudinal than in tangential direction due to the anatomical structure of wood and the direction of vessel elements inside the wood. All fungi were isolated from the sapwood, except for X. frustulatus which was isolated from the zone of heartwood. The phenomenon of callusing in the zones of mechanical injuries was observed by inspection. The occurrence of dead branches and leaf chlorosis couldn’t be directly related to the presence of the tested fungi inside the wood because some of the control trees also changed the indexes of dieback during the test, thus it couldn’t be confirmed that the artificial inoculation was the agent of chlorosis.
        Keywords:Quercus robur, Stereum hirsutum, Chondrostereum purpureum, Stereum rugosum, Xylobolus frustulatus, mycelium spread