The aim of this study was to assess diversity and composition of fungal communities in damaged and undamaged shoots of Norway spruce (Picea abies) following recent invasion of the spruce bud scale (Physokermes piceae) in Lithuania. Sampling was done in July 2013 and included 50 random lateral shoots from 10 random trees in each of five visually undamaged and five damaged 40-50 years-old pure stands of P. abies. DNA was isolated from 500 individual shoots, subjected to amplification of the internal transcribed spacer of fungal ribosomal DNA (ITS rDNA), barcoded and sequenced. Clustering of 149426 high-quality sequences resulted in 1193 non-singleton contigs of which 1039 (87.1%) were fungal. In total, there were 893 fungal taxa in damaged shoots and 608 taxa in undamaged shoots (p<0.0001). Furthermore, 431 (41.5%) fungal taxa were exclusively in damaged shoots, 146 (14.0%) were exclusively in undamaged shoots and 462 (44.5%) were common to both types of samples. Correspondence analysis showed that study sites representing damaged and undamaged shoots were separated from each other, indicating that in these fungal communities were largely different, and therefore heavily affected by P. piceae. In conclusion, the results demonstrated that invasive alien tree pests may have a profound effect on fungal mycobiota associated with the phyllosphere of P. abies, and therefore, in addition to their direct negative effect owing physical damage of the tissue, they may also indirectly determine health, sustainability and ultimately distribution of the forest tree species.Keywords: forest health, pathogens, pest insects, climate change, fungal community Introduction Norway spruce (Picea abies) is one of the dominant tree species distributed in a larger part of the north temperate and boreal forests of Europe, and therefore is of tremendous socioeconomic importance [33]. It appears that the climate has been the major determinant of the distributional limits of the tree species and these limits track climate change so closely that even short-term climatic variation can lead to significant range adjustments with consequences for practical forestry and society [39]. The recent observations suggest that the range limit of P. abies has begun to change more rapidly than in the past, and a further projection predicts its range expansion in the north and much greater contraction in the south of the present limit [3]. Climate change can affect forests directly (storms, droughts, high

The aim was to assess fungal communities associated with living needles and soil of Pinus sylvestris in managed and unmanaged forest stands to get a better understanding of whether and how different intensities of forest management affects fungal diversity and community composition under the north temperate forest zone conditions. The study was carried out in three national parks in Lithuania. Each included five study sites in managed stands and five in unmanaged stands. At each site, three random soil cores and five random last-year needle samples were collected. Following DNA isolation, a DNA fragment of the ITS2 rRNA gene region of each sample was individually amplified and subjected to high-throughput sequencing. Analysis of 195,808 high-quality reads showed the presence of 1909 fungal taxa. Richness and composition of fungal taxa were similar in each substrate (needles and soil) in managed vs. unmanaged sites. The most common fungi in needles were Coleosporium campanulae (12.4% of all fungal sequences), Unidentified sp. 3980_1 (12.4%), Unidentified sp. 3980_4 (4.1%) and Sydowia polyspora (3.1%). In soil: Unidentified sp. 3980_21 (8.6%), Umbelopsis nana (8.2%), Archaeorhizomyces sp. 3980_5 (8.1%) and Penicillium spinulosum (6.3%). The results demonstrated that managed and unmanaged P. sylvestris stands support similar diversity and composition of fungal communities associated with living needles and soil.

The aim of the present study was to assess fungal and oomycete communities in the irrigation water of forest nurseries, focusing on plant pathogens in the hope of getting a better understanding of potential pathogenic microorganisms and spreading routes in forest nurseries. The study sites were at Anykščiai, Dubrava, Kretinga and Trakai state forest nurseries in Lithuania. For the collection of microbial samples, at each nursery five 100-L water samples were collected from the irrigation ponds and filtered. Following DNA isolation from the irrigation water filtrate samples, these were individually amplified using ITS rDNA as a marker and subjected to PacBio high-throughput sequencing. Clustering in the SCATA pipeline and the taxonomic classification of 24,006 high-quality reads showed the presence of 1286 non-singleton taxa. Among those, 895 were representing fungi and oomycetes. The detected fungi were 57.3% Ascomycota, 38.1% Basidiomycota, 3.1% Chytridiomycota, 0.8% Mucoromycota and 0.7% Oomycota. The most common fungi were Malassezia restricta E. Guého, J. Guillot & Midgley (20.1% of all high-quality fungal sequences), Pezizella discreta (P. Karst.) Dennis (10.8%) and Epicoccum nigrum Link (4.9%). The most common oomycetes were Phytopythium cf. citrinum (B. Paul) Abad, de Cock, Bala, Robideau, Lodhi & Lévesque (0.4%), Phytophthora gallica T. Jung & J. Nechwatal (0.05%) and Peronospora sp. 4248_322 (0.05%). The results demonstrated that the irrigation water used by forest nurseries was inhabited by a species-rich but largely site-specific communities of fungi. Plant pathogens were relatively rare, but, under suitable conditions, these can develop rapidly, spread efficiently through the irrigation system and be a threat to the production of high-quality tree seedlings.

The production of tree seedlings in forest nurseries and their use in the replanting of clear-cut forest sites is a common practice in the temperate and boreal forests of Europe. Although conifers dominate on replanted sites, in recent years, deciduous tree species have received more attention due to their often-higher resilience to abiotic and biotic stress factors. The aim of the present study was to assess the belowground fungal communities of bare-root cultivated seedlings of Alnus glutinosa, Betula pendula, Pinus sylvestris, Picea abies and Quercus robur in order to gain a better understanding of the associated fungi and oomycetes, and their potential effects on the seedling performance in forest nurseries and after outplanting. The study sites were at the seven largest bare-root forest nurseries in Lithuania. The sampling included the roots and adjacent soil of 2–3 year old healthy-looking seedlings. Following the isolation of the DNA from the individual root and soil samples, these were amplified using ITS rRNA as a marker, and subjected to high-throughput PacBio sequencing. The results showed the presence of 161,302 high-quality sequences, representing 2003 fungal and oomycete taxa. The most common fungi were Malassezia restricta (6.7% of all of the high-quality sequences), Wilcoxina mikolae (5.0%), Pustularia sp. 3993_4 (4.6%), and Fusarium oxysporum (3.5%). The most common oomycetes were Pythium ultimum var. ultimum (0.6%), Pythium heterothallicum (0.3%), Pythium spiculum (0.3%), and Pythium sylvaticum (0.2%). The coniferous tree species (P. abies and P. sylvestris) generally showed a higher richness of fungal taxa and a rather distinct fungal community composition compared to the deciduous tree species (A. glutinosa, B. pendula, and Q. robur). The results demonstrated that the seedling roots and the rhizosphere soil in forest nurseries support a high richness of fungal taxa. The seedling roots were primarily inhabited by saprotrophic and mycorrhizal fungi, while fungal pathogens and oomycetes were less abundant, showing that the cultivation practices used in forest nurseries secured both the production of high-quality planting stock and disease control.

Climate change, which leads to higher temperatures, droughts, and storms, is expected to have a strong effect on both health of forest trees and associated biodiversity. The aim of this study was to investigate the diversity and composition of fungal communities associated with the functional tissues and rhizosphere soil of healthy-looking Picea abies to better understand these fungal communities and their potential effect on tree health in the process of climate change. The study sites included 30 P. abies stands, where needles, shoots, roots, and the rhizosphere soil was sampled. DNA was isolated from individual samples, amplified using ITS2 rRNA as a marker and subjected to high-throughput sequencing. The sequence analysis showed the presence of 232,547 high-quality reads, which following clustering were found to represent 2701 non-singleton fungal OTUs. The highest absolute richness of fungal OTUs was in the soil (1895), then in the needles (1049) and shoots (1002), and the lowest was in the roots (641). The overall fungal community was composed of Ascomycota (58.3%), Basidiomycota (37.2%), Zygomycota (2.5%), Chytridiomycota (1.6%), and Glomeromycota (0.4%). The most common fungi based on sequence read abundance were Aspergillus pseudoglaucus (7.9%), Archaeorhizomyces sp. (3.6%), and Rhinocladiella sp. (2.0%). Pathogens were relatively rare, among which the most common were Phacidium lacerum (1.7%), Cyphellophora sessilis (1.4%), and Rhizosphaera kalkhoffii (1.4%). The results showed that the detected diversity of fungal OTUs was generally high, but their relative abundance varied greatly among different study sites, thereby highlighting the complexity of interactions among the host trees, fungi, and local environmental conditions.