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In forest nurseries seedlings are commonly produced using different cultivation systems which may have a profound effect on the extent of root colonisation by ectomycorrhizal (ECM) fungi and, consequently, on subsequent performance of the outplanted seedlings under field conditions. In this study, we compare effects of bare-root and containerised cultivation systems on mycorrhization, establishment and growth of nursery-produced Picea abies. One hectare experimental plantation was established on poor fertility sandy site. In total, 1250 seedlings of each treatment were planted in rows as ten individual replicates. The results of this study showed that production of P. abies seedlings using containerised system can yield abundant ECM colonisation of seedling roots and significantly improve seedling survival in the field. Some reduction in height increment may occur during the first years as a possible cost for support of ECMs. Study demonstrated that selection of proper cultivation system might result in similar or higher mycorrhization and survival rates of outplanted seedlings than achieved by expensive and laborious artificial mycorrhization.

Tree stumps are expected to be increasingly used for energy production in Fennoscandia, thus environmental consequences of stump removal from forest land must be assessed. Aim of this work was to compile available data on the efficacy of stump removal in eradication of root rot fungi (Heterobasidion, Armillaria, and Phellinus), and to review its potential impacts on establishment and productivity of next forest generation. Site disturbance and some technical and economical aspects are discussed, and needs for future research outlined in northern European context. The review demonstrates that stump removal from clear-felled forest areas in most cases results in, a) reduction of root rot in the next forest generation, b) improved seedling establishment, and c) increased tree growth and stand productivity. Observed disturbances caused to a site by stumping operations are normally acceptable. The available data strongly suggests that possibly many (if achievable, all) rot-containing stumps must be removed during harvesting of stumps. Provided equal availability, the priority should be given for stump removal from root rot-infested forest areas, instead of healthy ones. As most studies were done in North America and Britain, several questions must be yet answered under Fennoscandian conditions: a) if and to which extent the conventional stump removal for biofuel on clear-felled sites could reduce the occurrence of Heterobasidion and Armillaria in the next forest generation, b) what impact is it likely to have on survival of replanted tree seedlings, and c) what consequences will there be for growth and productivity of next forest generation.

The aim of this study was to assess the extent of bark stripping wounds, subsequent wood discoloration, and associated fungi in 30-year-old Pinus contorta Douglas ex Loudon stems damaged by large game. In total, 90 trees were evaluated, and 170 bark stripping wounds of different ages (1-20 years) were measured. From each wound, wood samples were collected for subsequent fungal isolation. Thirty trees were cut to evaluate the length of the discoloration column. Of 170 injuries, 16 of them represented closed scars and 154 of them represented open wounds that exposed 4-4355 [cm.sup.2] of sapwood. The wound length had a strong impact on the length of decay (r = 0.716); however, the spread of discoloration beyond the wound margin was limited (0-20 cm). The most commonly isolated fungus was Sarea difformis (Fr.) Fr. and, among the Basidiomycetes, Peniophora pini (Schleich.) Boidin. The results suggest that when planning to grow P. contorta in areas of Europe, the population size of large game animals needs to be considered, in view of potential risk of bark stripping damage. Key words: lodgepole pine, bark stripping wounds, wood discoloration. Le but de cette etude etait d'evaluer l'etendue des blessures d'ecorcage, la coloration subsequente et les champignons associes sur des tiges de Pinus contorta Douglas ex Loudon agees de 30 ans et endommagees par le gros gibier. Au total, 90 arbres ont ete evalues et 170 blessures d'ecorcage de differents ages (1-20 ans) ont ete mesurees. Des echantillons de bois ont ete preleves dans chaque blessure pour l'isolation subsequente des champignons. Trente arbres ont ete coupes pour evaluer la longueur de la colonne de coloration. Des 170 blessures, 13 representaient des cicatrices fermees et 154 des blessures ouvertes oU 4 a 4355 [cm.sup.2] de bois d'aubier etait expose. La longueur de la blessure avait un impact important sur la longueur de la carie (r = 0,716), par contre la progression de la coloration au-dela de la marge de la blessure etait limitee (0-20 cm). Le champignon qui a ete isole le plus souvent etait Sarea difformis (Fr.) Fr. et, parmi les Basidiomycetes, Peniophora pini (Schleich.) Boidin. Les resultats indiquent qu'on doit tenir compte de la taille des populations de gros gibier, etant donne les risques de blessures d'ecorcage, si on envisage de cultiver P. contorta dans certaines regions de l'Europe. [Traduit par la Redaction] Mots-cles: pin tordu, blessures d'ecorcage, coloration du bois., Introduction In Latvia, experimental plantations of Pinus contorta Douglas ex Loudon were established in years 1979-1981, with native Pinus sylvestris L. simultaneously planted as a control (Baumanis and Birgelis 1993). [...]

Abstract Background Many fungi are obligate biotrophs of plants, growing in live plant tissues, gaining direct access to recently photosynthesized carbon. Photosynthate within plants is transported from source to sink tissues as sucrose, which is hydrolyzed by plant glycosyl hydrolase family 32 enzymes (GH32) into its constituent monosaccharides to meet plant cellular demands. A number of plant pathogenic fungi also use GH32 enzymes to access plant-derived sucrose, but less is known about the sucrose utilization ability of mutualistic and commensal plant biotrophic fungi, such as mycorrhizal and endophytic fungi. The aim of this study was to explore the distribution and abundance of GH32 genes in fungi to understand how sucrose utilization is structured within and among major ecological guilds and evolutionary lineages. Using bioinformatic and PCR-based analyses, we tested for GH32 gene presence in all available fungal genomes and an additional 149 species representing a broad phylogenetic and ecological range of biotrophic fungi. Results We detected 9 lineages of GH32 genes in fungi, 4 of which we describe for the first time. GH32 gene number in fungal genomes ranged from 0–12. Ancestral state reconstruction of GH32 gene abundance showed a strong correlation with nutritional mode, and gene family expansion was observed in several clades of pathogenic filamentous Ascomycota species. GH32 gene number was negatively correlated with animal pathogenicity and positively correlated with plant biotrophy, with the notable exception of mycorrhizal taxa. Few mycorrhizal species were found to have GH32 genes as compared to other guilds of plant-associated fungi, such as pathogens, endophytes and lichen-forming fungi. GH32 genes were also more prevalent in the Ascomycota than in the Basidiomycota. Conclusion We found a strong signature of both ecological strategy and phylogeny on GH32 gene number in fungi. These data suggest that plant biotrophic fungi exhibit a wide range of ability to access plant-synthesized sucrose. Endophytic fungi are more similar to plant pathogens in their possession of GH32 genes, whereas most genomes of mycorrhizal taxa lack GH32 genes. Reliance on plant GH32 enzyme activity for C acquisition in these symbionts supports earlier predictions of possible plant control over C allocation in the mycorrhizal symbiosis.

The island of Gotland (Sweden) possesses the largest (more than one million trees) wild population of elms in northern Europe, which until recently was not affected by Dutch elm disease (DED). In 2005, DED was observed for the first time in the northeastern part of Gotland, and in the following years, it rapidly spread in all directions, generally following the major distribution of elms. Implementation of intensive control measures including ground surveys and geographic information system mapping of DED-diseased trees, their felling and destruction, and stump treatment with the herbicide glyphosate allowed reduction of the source of infection and probably suppression of an otherwise very rapid spread of the disease. Monitoring the flying periods ofScolytus multistriatusvector beetles between the years 2007 and 2011 showed that the abundance of trapped beetles in most cases differed significantly among individual years. Over the entire monitoring period, 55.2% of the beetles were trapped in June, 31.2% in July and 13.5% in August (difference among individual months significant atp < .0001). In conclusion, the study demonstrated the seasonal flying patterns ofS. multistriatus, suggesting that the removal of trees attacked in the previous vegetation period as a combat measure should be completed before the beginning of the flying season ofS. multistriatus, and that the application of the integrated DED management has the potential to arrest the development of the disease in a geographically isolated area such as Gotland. [ABSTRACT FROM PUBLISHER]

The interest in Alnus glutinosa (L.) Gaertn. as plantation species has increased during last years, but its prospects should be evaluated from the perspective of forest health. The aims of the present study were to: (1) estimate the incidence of stem decay in Latvian A. glutinosa stands, (2) measure the extent of decay within individual stems and on a stand level and (3) identify decay-causing fungi. In four A. glutinosa stands, 450 trees were randomly sampled with an increment borer and the presence/absence of decay was recorded. As a result, 112 sound-looking and 338 decayed trees were detected, and a corresponding number of wood samples were collected for fungal isolations. A total of 34 stems with decay symptoms were cut to measure the extent of internal decay. The incidence of decayed stems in studied stands was 75.1% on average. The length of the decay column was 7.7±5.4 m on average, and that of spongy rot was 4.2±4.5 m on average, implying that yield losses for fully stocked 80-years-old A. glutinosa stand would comprise 49.2% of the total stand volume, and the losses from spongy rot alone – 30.5%. In total, 1134 isolates representing 68 fungal taxa were obtained. The most common decay-causing fungi were Inonotus radiatus and Armillaria sp. [ABSTRACT FROM AUTHOR]

Dieback of Fraxinus excelsior L. associated with Chalara fraxinea is observed in Europe, and in some areas dying trees exhibit symptoms of root and butt rot. Our study was conducted (1) to estimate the impact of the rot on F. excelsior dieback severity; (2) to identify fungi colonizing roots of dieback-affected trees; (3) to check their pathogenicity to F. excelsior; and (4) to estimate sprouting incidence and sprout health condition in relation to presence/absence of rot. The extent of rot was measured in 33 trees with different dieback intensity, 150 fungal isolations were attempted from roots of 50 trees, 26 fungi were tested for pathogenicity to 286 saplings, and sprouting was evaluated for 328 stumps on three clear-felled sites. Root rot was mainly caused by Armillaria cepistipes, and the extent of rot correlated positively with dieback severity although it played a secondary role in tree decline. Four years after tree felling, root rot had a negative impact on sprouting frequency, yet rot did not enter sprouts from stumps, and when experimentally inoculated, fungi associated with root rot in mature ash had no visible impact on tree vigor, showing that after formation of sprouts, rot does not affect the subsequent phytosanitary condition. Sprouts on investigated sites exhibited Chalara dieback symptoms on leaves and bark irrespectively of presence/absence of rot, indicating that vigorous natural regeneration of F. excelsior in dieback-affected areas could not be expected. [ABSTRACT FROM AUTHOR]