| Abstract: | The annual dynamics of birch crown thinning was studied by collecting fallen twigs monthly for two years. The detachment of birch twigs that had died during the summer was also followed. In addition, the fungi sporulating on the detached twigs were investigated by photomicroscopy to reveal morphological characters, and by DNA analyses to identify relationships between the fungi. The twigs that had died during the summer fell to the ground during the following winter and spring. Crown thinning, however, peaked in summer and early autumn. Altogether seven sporulating fungi were identified from the detached twigs. The most common fungus was Pleomassaria siparia (the teleomorph of both Prosthemium betulinum and P. asterosporum). The connection between crown thinning and fungi was not clear, but the results suggested that Pleomassaria siparia could be involved in the process. |
