Foliar fungi of Scots pine (Pinus sylvestris)

Sammanfattning: Scots pine (Pinus sylvestris) is an ecologically and economically important tree species in Fennoscandia. Scots pine needles host a variety of fungi, some with the potential to profoundly influence their host. These fungi can have beneficial or detrimental effects with important implications for both forest health and primary production. In this thesis, the foliar fungi of Scots pine needles were investigated with the aim of exploring spatial and temporal patterns, and development with needle age and health status. Using 454 sequencing, diverse fungal communities were detected from Scots pine needles sampled along latitudinal and altitudinal gradients in Sweden and from forests along the Lithuanian coast. Latitude and altitude, as well as the forest edge, were found to influence the fungal community. Needle age and needle heath status affected the fungal community, while OTU (operational taxonomic unit) richness increased with needle age and in symptomatic needles. In addition, Dothistroma needle blight (DNB) was examined under Nordic conditions on seedlings of Scots pine and Lodgepole pine (Pinus contorta). The disease development of DNB was found to be comparable to what has been reported in studies from Europe and New Zealand. Findings in this thesis show that the fungal community associated with Scots pine needles is species rich, but the majority of these fungi have unknown ecological roles. Our results contribute to the understanding of spatial variability and dynamics of these fungi, which is important for better understanding of their potential effect on ecosystem processes.