Harmonised statistics and maps of forest biomass and increment in Europe.

Forest biomass is an essential resource in relation to the green transition and its assessment is key for the sustainable management of forest resources. Here, we present a forest biomass dataset for Europe based on the best available inventory and satellite data, with a higher level of harmonisation and spatial resolution than other existing data. This database provides statistics and maps of the forest area, biomass stock and their share available for wood supply in the year 2020, and statistics on gross and net volume increment in 2010-2020, for 38 European countries. The statistics of most countries are available at a sub-national scale and are derived from National Forest Inventory data, harmonised using common reference definitions and estimation methodology, and updated to a common year using a modelling approach. For those counties without harmonised statistics, data were derived from the State of Europe's Forest 2020 Report at the national scale. The maps are coherent with the statistics and depict the spatial distribution of the forest variables at 100 m resolution.

Quality of life: A way to buttress crisis program evaluations?

To test the applicability of the quality of life concept (QoL) in evaluations of financial assistance programs to sovereigns, we apply the OECD well-being framework to the programs in a euro area country, and find that the multidimensional framework promises policy-relevant findings, capable of informing other approaches for evaluating program relevance and effectiveness. The framework's headline indicators nevertheless, needed to be complemented with additional indicators owing to data challenges. The well-being dimensions demonstrate that our primary country case and other assisted euro area countries struggled to protect some vulnerable groups before and during the crisis years, although many QoL indicators depict improvement once program completion approached. In many cases, gender, age and education level related differences were apparent, and should be better considered in future crisis programs. The framework also facilitates considering governance elements with our enhancements. It offers good grounds for deepening the understanding of stakeholders' perception of reform benefits or shortcomings, thus of program ownership. By using the OECD framework we explore some interpretative limits of QoL in evaluation, and underscore that a full program evaluation would require careful integration in primary case data. Further research and data set improvements would enhance this approach's utility.

Functional traits and climate drive interspecific differences in disturbance-induced tree mortality.

With climate change, natural disturbances such as storm or fire are reshuffled, inducing pervasive shifts in forest dynamics. To predict how it will impact forest structure and composition, it is crucial to understand how tree species differ in their sensitivity to disturbances. In this study, we investigated how functional traits and species mean climate affect their sensitivity to disturbances while controlling for tree size and stand structure. With data on 130,594 trees located on 7617 plots that were disturbed by storm, fire, snow, biotic or other disturbances from the French, Spanish, and Finnish National Forest Inventory, we modeled annual mortality probability for 40 European tree species as a function of tree size, dominance status, disturbance type, and intensity. We tested the correlation of our estimated species probability of disturbance mortality with their traits and their mean climate niches. We found that different trait combinations controlled species sensitivity to disturbances. Storm-sensitive species had a high height-dbh ratio, low wood density and high maximum growth, while fire-sensitive species had low bark thickness and high P50. Species from warmer and drier climates, where fires are more frequent, were more resistant to fire. The ranking in disturbance sensitivity between species was overall consistent across disturbance types. Productive conifer species were the most disturbance sensitive, while Mediterranean oaks were the least disturbance sensitive. Our study identified key relations between species functional traits and disturbance sensitivity, that allows more reliable predictions of how changing climate and disturbance regimes will impact future forest structure and species composition at large spatial scales.

Modelling the effect of moose Alces alces population density and regional forest structure on the amount of damage in forest seedling stands.

BACKGROUND: Moose (Alces alces L.) populations and moose damage in forests are debated in Nordic countries with dense moose populations. Moose populations and food resources vary greatly, both spatially and temporally, and reliable data covering both variables simultaneously at the same scale have seldom been available. We modelled the effect of moose population density and forest resources on the area of moose damage at regional scale, referring to moose management areas (MMA). Forest data and moose damage data originated from the Finnish National Forest Inventory, and the moose population data came from a Bayesian moose model. For modelling, average values of moose population, damage and forest variables were calculated for the periods 2004-2008 and 2009-2013 for each MMA. The MMAs were further classified into one of four larger geographical zones. The area of moose damage was used as a dependent variable, and the proportions of different types of forests and moose population densities per land area or area of seedling stands as explanatory variables. The relationships were modelled with a linear mixed-effects model with an exponential spatial correlation structure. RESULTS: The area of moose damage was best explained by total forest area, proportions of plantations and mature forests, and moose population density per land area or the proportion of plantations. There were differences among the biogeographical zones in how different variables explained the amount of damage. CONCLUSION: The results provide tools for analyzing the regional effects of moose population density and the amount of food resources on the amount of moose damage. This information can be used in reconciling sustainable moose population levels and the amount of damage.

An Updated Global Species Diversity and Phylogeny in the Forest Pathogenic Genus Heterobasidion (Basidiomycota, Russulales).

Heterobasidion species are amongst the most intensively studied polypores because several species are aggressive white rot pathogens of managed coniferous forests mainly in Europe and North America. In the present study, both morphological and multilocus phylogenetic analyses were carried out on Heterobasidion samples from Asia, Oceania, Europe and North America. Three new taxa were found, i.e., H. armandii, H. subinsulare, and H. subparviporum are from Asia and are described as new species. H. ecrustosum is treated as a synonym of H. insulare. So far, six taxa in the H. annosum species complex are recognized. Heterobasidion abietinum, H. annosum, and H. parviporum occur in Europe, H. irregulare, and H. occidentale in North America, and H. subparviporum in East Asia. The North American H. irregulare was introduced to Italy during the Second World War. Species in the H. annosum complex are pathogens of coniferous trees, except H. subparviporum that seems to be a saprotroph. Ten species are found in the H. insulare species complex, all of them are saprotrophs. The pathogenic species are distributed in Europe and North America; the Asian countries should consider the European and North American species as entry plant quarantine fungi. Parallelly, European countries should consider the American H. occidentale and H. irregulare as entry plant quarantine fungi although the latter species is already in Italy, while North America should treat H. abietinum, H. annosum s.s., and H. parviporum as entry plant quarantine fungi. Eight Heterobasidion species found in the Himalayas suggest that the ancestral Heterobasidion species may have occurred in Asia.

Insights into the phylogeny of Northern Hemisphere Armillaria: Neighbor-net and Bayesian analyses of translation elongation factor 1-α gene sequences.

Armillaria possesses several intriguing characteristics that have inspired wide interest in understanding phylogenetic relationships within and among species of this genus. Nuclear ribosomal DNA sequence-based analyses of Armillaria provide only limited information for phylogenetic studies among widely divergent taxa. More recent studies have shown that translation elongation factor 1-α (tef1) sequences are highly informative for phylogenetic analysis of Armillaria species within diverse global regions. This study used Neighbor-net and coalescence-based Bayesian analyses to examine phylogenetic relationships of newly determined and existing tef1 sequences derived from diverse Armillaria species from across the Northern Hemisphere, with Southern Hemisphere Armillaria species included for reference. Based on the Bayesian analysis of tef1 sequences, Armillaria species from the Northern Hemisphere are generally contained within the following four superclades, which are named according to the specific epithet of the most frequently cited species within the superclade: (i) Socialis/Tabescens (exannulate) superclade including Eurasian A. ectypa, North American A. socialis (A. tabescens), and Eurasian A. socialis (A. tabescens) clades; (ii) Mellea superclade including undescribed annulate North American Armillaria sp. (Mexico) and four separate clades of A. mellea (Europe and Iran, eastern Asia, and two groups from North America); (iii) Gallica superclade including Armillaria Nag E (Japan), multiple clades of A. gallica (Asia and Europe), A. calvescens (eastern North America), A. cepistipes (North America), A. altimontana (western USA), A. nabsnona (North America and Japan), and at least two A. gallica clades (North America); and (iv) Solidipes/Ostoyae superclade including two A. solidipes/ostoyae clades (North America), A. gemina (eastern USA), A. solidipes/ostoyae (Eurasia), A. cepistipes (Europe and Japan), A. sinapina (North America and Japan), and A. borealis (Eurasia) clade 2. Of note is that A. borealis (Eurasia) clade 1 appears basal to the Solidipes/Ostoyae and Gallica superclades. The Neighbor-net analysis showed similar phylogenetic relationships. This study further demonstrates the utility of tef1 for global phylogenetic studies of Armillaria species and provides critical insights into multiple taxonomic issues that warrant further study.

Viruses accumulate in aging infection centers of a fungal forest pathogen.

Fungal viruses (mycoviruses) with RNA genomes are believed to lack extracellular infective particles. These viruses are transmitted laterally among fungal strains through mycelial anastomoses or vertically via their infected spores, but little is known regarding their prevalence and patterns of dispersal under natural conditions. Here, we examined, in detail, the spatial and temporal changes in a mycovirus community and its host fungus Heterobasidion parviporum, the most devastating fungal pathogen of conifers in the Boreal forest region. During the 7-year sampling period, viruses accumulated in clonal host individuals as a result of indigenous viruses spreading within and between clones as well as novel strains arriving via airborne spores. Viral community changes produced pockets of heterogeneity within large H. parviporum clones. The appearance of novel viral infections in aging clones indicated that transient cell-to-cell contacts between Heterobasidion strains are likely to occur more frequently than what was inferred from genotypic analyses. Intraspecific variation was low among the three partitivirus species at the study site, whereas the unassigned viral species HetRV6 was highly polymorphic. The accumulation of point mutations during persistent infections resulted in viral diversification, that is, the presence of nearly identical viral sequence variants within single clones. Our results also suggest that co-infections by distantly related viral species are more stable than those between conspecific strains, and mutual exclusion may play a role in determining mycoviral communities.

Evidence of natural hybridization among homothallic members of the basidiomycete Armillaria mellea sensu stricto.

Populations of Armillaria mellea (Basidiomycota, Agaricales) across much of its range are heterothallic; homothallic populations occur only in Africa (A. mellea ssp. africana), China (China Biological Species CBS G), and Japan (A. mellea ssp. nipponica). Monosporous isolates of heterothallic A. mellea are haploid and their mating behaviour is consistent with the requirement of two different alleles at two mating-type loci (tetrapolar mating system) to create a diploid individual. In contrast, monosporous isolates of homothallic A. mellea are putatively diploid; they bypass the haploid phase by undergoing karyogamy in the basidium (a unique type of secondary homothallism/pseudohomothallism). In order to determine the genetic origin of this homothallism, we analyzed genetic variation of 47 heterothallic isolates from China, Europe, and North America, and 14 homothallic isolates from Africa, China, and Japan. Gene trees and mutational networks were constructed for partial mitochondrial gene ATP synthase subunit 6 (ATP6) and for the following nuclear genes: actin (ACTIN), elongation factor subunit 1-alpha (EFA), glyceraldehyde 3-phosphate dehydrogenase (GPD), and the RNA polymerase subunit II (RPB2). Homothallic isolates from Africa and Japan shared a common mitochondrial ATP6 haplotype with homothallic isolates from China, and are likely introductions. Homothallic isolates from China that shared a common mitochondrial haplotype with all European isolates did not share European nuclear haplotypes, as revealed by median-joining networks, but instead clustered with haplotypes from China or were intermediate between those of China and Europe. Such mitochondrial-nuclear discordance in homothallic isolates from China is indicative of hybridization between lineages originating from China and Europe.

Population structure of a novel putative mycovirus infecting the conifer root-rot fungus Heterobasidion annosum sensu lato.

We describe a novel putative mycovirus infecting the conifer root-rot fungus Heterobasidion annosum sensu lato. This virus, designated as Heterobasidion RNA virus 6 (HetRV6), is taxonomically distant from all previously known viruses of Heterobasidion species, but somewhat related to the Curvularia thermal tolerance virus and the Fusarium graminearum virus 4. Based on a population analysis including 35 virus strains from Heterobasidion abietinum, Heterobasidion parviporum, Heterobasidion annosum sensu stricto and Heterobasidion occidentale, HetRV6 showed a considerable degree of geographical and host-related differentiation. The North American and Eurasian virus populations were clearly separated. In Eurasia, we observed cases of discrepancy between virus and host taxonomy, suggesting interspecies virus transfer. HetRV6 was also successfully transmitted between the three European species H. abietinum, H. annosum and H. parviporum. Based on growth rate tests on agar plates and spruce stem pieces, HetRV6 seemed to be cryptic or slightly mutualistic to its host.

Species of Heterobasidion host a diverse pool of partitiviruses with global distribution and interspecies transmission.

We investigated the geographic occurrence and genetic diversity of partitiviruses among 247 Heterobasidion specimens representing seven species and originating from Europe, Asia, and North America. Based on sequence analysis, partitiviruses were relatively rare, and occurred only in about 5 % of the Heterobasidion isolates analyzed, constituting a minority (about 28 %) of all virus-infected [double-stranded RNA (dsRNA)-positive] isolates. Altogether ten virus strains were characterized in sequence: one complete genome sequence of 3893 bp, six complete RNA-dependent RNA polymerase sequences of 2000-2033 bp, and three partial polymerase sequences. Based on phylogenetic analysis, the virus strains were assigned into three putative partitivirus species: HetRV1 (Heterobasidion RNA virus 1), HetRV4, and HetRV5. Degenerate consensus primers were designed for RT-PCR detection of these virus species. HetRV1 occurred in five different Heterobasidion species, and resembled the previously described Heterobasidion annosum virus (HaV). Highly similar HetRV1 strains with 98 % nucleotide level similarity were found from H. parviporum (member of the H. annosum species complex) and H. australe (member of the H. insulare complex) growing in the same region in Bhutan. This observation suggests recent virus transmission between these taxonomically distant Heterobasidion species in nature. It was also shown that HetRV1 can be transmitted by mycelial contact between the H. annosum and H. insulare complexes. The two other virus species, HetRV4 and HetRV5, were closely related to the Amasya Cherry Disease-associated mycovirus, to Heterobasidion parviporum partitivirus Fr110B, and also to several plant-infecting alphacryptoviruses. These results are in accordance with the view of a close evolutionary relationship between partitiviruses of plants and fungi.

Incidence of Phlebiopsis gigantea large virus-1 in a collection of Phlebiopsis gigantea isolates.

Eighty six Phlebiopsis gigantea isolates from at least 9 different tree species from various locations in 12 different European countries and North America were screened for the presence of large molecular weight dsRNA >10 kbp in size. In 7 isolates, which contained large dsRNAs, the presence of Phlebiopsis gigantea large virus-1 (PgLV-1) was suggested following the sequencing of the RT-PCR amplicons generated with PgLV-1 specific oligonucleotide primers which also revealed little genetic diversity between the virus isolates.

A novel putative partitivirus of the saprotrophic fungus Heterobasidion ecrustosum infects pathogenic species of the Heterobasidion annosum complex.

We characterized the bisegmented genome of a putative double-stranded (ds) RNA virus from a Chinese isolate of the fungus Heterobasidion ecrustosum, a member of the Heterobasidion insulare species complex. The larger genomic segment of 1885bp encoded a putative RNA dependent RNA polymerase (RdRp, 585aa), and the smaller one for a putative coat protein of 521aa (1826bp). Phylogenetic analyses suggest that this novel virus species, named as 'Heterobasidion RNA virus 3 from H. ecrustosum, strain 1' (HetRV3-ec1), can be assigned to the family Partitiviridae, being most similar to the Helicobasidium mompa dsRNA mycovirus with RdRp amino acid similarity of 54%. The similarity to known viruses of other Heterobasidion species was notably low (25-39%). The virus could be experimentally transmitted to members of the Heterobasidion annosum complex: the European Heterobasidion abietinum and North American Heterobasidion occidentale, and the original host strain could be cured from the virus by thermal treatment. Microscopical observations showed that hyphae of H. ecrustosum anastomosed occasionally with H. abietinum and H. occidentale, and suggested a possible route for horizontal transmission between these sexually incompatible species. The virus infection seemed to cause variable effects on the growth rate of its fungal hosts, but the results were strongly dependent on fungal strain, growth medium and incubation temperature.

Use of a breeding approach for improving biocontrol efficacy of Phlebiopsis gigantea strains against Heterobasidion infection of Norway spruce stumps.

Sixty-four wild heterokaryotic isolates of Phlebiopsis gigantea were analysed for asexual spore production, growth rate and competitive ability against Heterobasidion in vitro, as well as growth rate in Norway spruce wood. These P. gigantea traits were considered important for controlling infection of Norway spruce stumps by spores of Heterobasidion spp. Ten most promising P. gigantea isolates were crossed with each other and 172 F(1) progeny heterokaryons were analysed for the above-mentioned traits. Thirteen most promising progeny heterokaryons were selected and their biocontrol ability against infection by Heterobasidion was compared with the parental isolates in stem pieces of Norway spruce. The results indicated that the progeny strains had generally better traits and control efficacy than the parental strains. The genetic effects accounted for a part of the variations between progeny and parental strains. This further suggests that there is a potential to improve the biocontrol properties of P. gigantea through breeding.

Sensitivity of managed boreal forests in Finland to climate change, with implications for adaptive management.

This study investigated the sensitivity of managed boreal forests to climate change, with consequent needs to adapt the management to climate change. Model simulations representing the Finnish territory between 60 and 70 degrees N showed that climate change may substantially change the dynamics of managed boreal forests in northern Europe. This is especially probable at the northern and southern edges of this forest zone. In the north, forest growth may increase, but the special features of northern forests may be diminished. In the south, climate change may create a suboptimal environment for Norway spruce. Dominance of Scots pine may increase on less fertile sites currently occupied by Norway spruce. Birches may compete with Scots pine even in these sites and the dominance of birches may increase. These changes may reduce the total forest growth locally but, over the whole of Finland, total forest growth may increase by 44%, with an increase of 82% in the potential cutting drain. The choice of appropriate species and reduced rotation length may sustain the productivity of forest land under climate change.

Thermophilic aeration of cattle slurry with whey and/or jam wastes.

Thermophilic aeration of cattle slurry and food industrial by-products was studied with the aim to improve hygienic qualities of the slurry so that it could be used as a safe fertiliser for berries to be eaten raw. We also wanted to study if the process would be energetically favourable in an arctic climate. Cattle slurry alone or with whey and/or jam waste was treated. The tests were done in a well heat-insulated reactor with a 10 m(3) volume. Temperature increases up to over 70 degrees C could be recorded in 19 days even though some processes were carried out in winter time when the ambient air temperature was less than 0 degrees C. The heat energy formed was higher than the electrical energy needed to carry out the aeration. The hygienic qualities of the aerated product were good with only minor nitrogen losses. The end product could be useful as a fertiliser and soil improving compound to increase the organic matter content of agricultural soil. Cattle slurry alone was well suited as the raw material if attaining a high temperature was the main goal. A part of slurry could be replaced with food-industrial side products. Whey waste suited better for co-composting than jam waste but the mixture of whey, jam waste, and slurry was optimal for composting.

An unknown mechanism promotes somatic incompatibility in Ceratobasidium bicorne.

Strains of Ceratobasidium bicorne (anamorph uninucleate Rhizoctonia), causing root dieback in nursery-grown conifer seedlings, were fruited in the laboratory and the pairing interactions among sibling, single-basidiospore progeny were investigated. No mating reactions were observed. Instead, a high frequency of somatic incompatibility was observed in progeny pairings, indicated by a killing reaction in hyphal anastomosis and by formation of a demarcation line. The F1 progeny also could be fruited, and the level of somatic incompatibility within the F2 progeny remained high, even if lower than in the F1 progeny. The interaction types in pairings within a family of progeny were similar in all respects to those between field isolates, indicating that the species is homothallic. The uninucleate condition of vegetative cells and the basidial characteristics would indicate homokaryotic fruiting, but the possibility of pseudohomothallism remains. We currently are not able to provide an explanation for the mechanism promoting somatic incompatibility in this species, but it seems likely that the classic heterogenic model of somatic incompatibility recognized in basidiomycetes is not applicable here. Alternative mechanisms are discussed.

Assessment of exposure in an international study on cancer risks among pulp, paper, and paper product workers.

A data management system and a department-exposure matrix (PAPDEM) was designed and constructed to facilitate exposure assessment for a large multinational study on cancer risks among pulp, paper, and paper product workers. Exposure to 25 major agents was described by prevalence, P (i.e., proportion of the exposed, classified %-range), and level, L (i.e., annual mean concentration at work, classified). Some agents could be assessed only in qualitative terms. The assessment was specific to mill, work department, agent, and time period. The results of industrial hygiene measurements, information from detailed company questionnaires, and the professional judgments of the assessment team were the cornerstones of the assessment. Validity and consistency of the assessment were aimed at by setting default values for P and L prior to the assessment, accurately defining agents and exposure classes, dividing assessment work by subindustry, working in pairs, testing interrater agreement, and finalizing the estimates in a meeting. In spite of these precautions, good agreement between different assessors was difficult to reach. Exposure to chemical agents turned out to be widespread and complex with frequent multiple exposures. A computer-assisted exposure assessment system such as PAPDEM may save time and facilitate assessment in large epidemiological studies requiring complicated exposure assessment procedures. It also provides a good documentation of exposure assignments, which may be useful in the interpretation of the results and in future updates of the study.