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Forest simulation models have been widely used to predict future stand structure. Generally these models do not include the understory vegetation and its response on stand structure change or other environmental factors. Previous simulation studies have shown that stand structure related variables, e.g. basal area, can explain diversity of the forest floor vegetation in boreal forests. We hypothesise that such variables also can be used to explain the performance of understory species and we conceptualise how plant ecology and forest modelling can be combined to predict the performance of understory plants in Norwegian boreal forests. We predict the performance of an understory plant species (Cornus suecica) over time using simulated values of forest variables as input to models expressing the relationship between forest environment variables and plant performance variables (viz. plant height, plant dry weight, number of flowers, number of branches and number of leaves). We also present relationships between plant performance and explanatory variables commonly used in basic ecological research, variables that currently not are readily compatible with forest simulators (e.g. soil chemical variables).We found basal area of canopy trees being the most important explanatory variable explaining C. suecica performance. The performance variable dry weight was predicted by one single model whereas the other performance variables were best predicted by model averaging. Forest simulations for 150 years showed values of plant performance of C. suecica to be reduced during forest succession.

Due to climate warming, forests are expanding to higher elevations and latitudes at the expense of tundra vegetation. While the subsequent increase in aboveground biomass is well‐documented, there is much speculation regarding the effects on soil organic carbon (SOC) stocks. To provide insight into the consequences of tree encroachment into treeless tundra, we sampled SOC stocks across 36 forest‐tundra ecotones along a 1100 km latitudinal gradient in Norway. Our results show that SOC stocks vary greatly within, as well as among treeline ecotones, and that SOC stocks do not correlate with tree biomass and tree species. SOC stocks do increase with temperature, and vary with slope steepness, slope aspect, and soil parent material. Applying a 'space‐for‐time substitution' perspective, our findings suggest that tree encroachment into tundra is unlikely to have immediate consequences for SOC stocks. [ABSTRACT FROM AUTHOR]

Fire in the boreal forests emits substantial amounts of organically bound carbon (C) to the atmosphere and converts a fraction of the burnt organic matter into charcoal, which in turn is highly refractory and functions as a long‐term stable C pool. It is well established that the boreal forest charcoal pool is sufficiently large to play a significant role in the global C cycle. However, there is a need for spatially representative estimates of how large proportions of the forest floor C pool are made up of charcoal across different plant communities in the boreal forest ecosystem. Thus, we have quantified the amounts of C separately in charcoal and the organic layers of the forest floor across fine spatial scales in a boreal forest landscape with a well‐documented fire history. We found that the proportion of charcoal C made up an average of 1.2% of the total forest floor C, and the charcoal proportions showed a high small‐scale spatial variability and were concentrated in the organic–mineral soil interface. Proportions of charcoal C decreased with increasing time since last fire. Deeper soils, denser soils, and local concave areas had the highest proportions of charcoal C, whereas historical fire frequencies and current differences in vegetation did not relate to the proportions of charcoal C. [ABSTRACT FROM AUTHOR]

Charcoal pools in boreal forest soils constitute considerable amounts of slow cycling organic matter that is important in the global carbon cycle. However, these pools are characterized by spatiotemporal variations that are not well understood. Here, we have analyzed the charcoal pool in 100 soil samples to determine charcoal stock species origin and how the size and age of this pool varies across different spatial scales in a Norwegian boreal forest landscape including forests that differ in terms of tree-species composition, tree density, and recent fire histories. The size of the charcoal pool was site-specific and highly variable, ranging from 0 to 2108 g-m-2. Geostatistical analyses showed that the charcoal pool was only weakly spatially structured at fine spatial scales (metres) and broader between-site scales (100s of metres). Unexpectedly, there was no significant relationship between the amount of charcoal and contemporary forest composition and density, although there was proportionally more charcoal from broadleaved trees in today's Scots pine forests than in the Norway spruce forests. When relating this information to the fire history, the results indicate that charcoal is lost at a millennial time scale. Key words: black carbon, charcoal age, charcoal amount, charcoal degradation, forest fire history, pyrogenic carbon. Les pools de charbon de bois dans les sols de la foret boreale recelent des quantites considerables de matiere organique lentement recyclee et importante dans le cycle global du carbone. Cependant, ces pools sont caracterises par des variations spatio-temporelles qui ne sont pas bien comprises. Nous avons examine le pool de charbon de bois dans 100 echantillons de sol pour determiner l'espece a l'origine du charbon de bois et de quelle facon la taille et l'age de ce pool varient en fonction de differentes echelles spatiales dans un paysage de foret boreale norvegienne, incluant des forets qui different en termes de composition en especes d'arbres, de densite des arbres et d'historique des feux. La taille du pool de charbon de bois etait propre a chaque station et tres variable, allant de 0 a 2108 g-m-2. Des analyses geostatistiques ont montre que les pools de charbon de bois etaient seulement faiblement structures a des echelles reduites, de l'ordre de quelques metres, et a plus grande echelle, soit celle des stations (de l'ordre de 100s de metres). Sans qu'on s'y attende, il n'y avait pas de relation significative entre la densite ou la composition de la foret contemporaine et la quantite de charbon de bois. Par contre, il y avait proportionnellement plus de charbon de bois provenant d'essences feuillues dans les forets de pin sylvestre d'aujourd'hui que dans les forets d'epicea commun. Lorsqu'on met cette information en relation avec l'historique des feux, les resultats indiquent que le charbon de bois disparait a l'echelle du millenaire. [Traduit par la Redaction] Mots-cles: carbone noir, age du charbon de bois, quantite de charbon de bois, degradation du charbon de bois, historique des feux de foret, carbone pyrogene., Introduction Charcoal derived from forest fires is an important part of the pyrogenic and slow cycling fraction of soil organic matter. Due to its importance in the global carbon cycle, [...]

Knowledge about the spatial variation of boreal forest soil carbon (C) stocks is limited, but crucial for establishing management practices that prevent losses of soil C. Here, we quantified the surface soil C stocks across small spatial scales, and aim to contribute to an improved understanding of the drivers involved in boreal forest soil C accumulation. Our study is based on C analyses of 192 soil cores, positioned and recorded systematically within a forest area of 11 ha. The study area is a south-central Norwegian boreal forest landscape, where the fire history for the past 650 years has been reconstructed. Soil C stocks ranged from 1.3 to 96.7 kg m−2 and were related to fire frequency, ecosystem productivity, vegetation attributes, and hydro-topography. Soil C stocks increased with soil nitrogen concentration, soil water content, Sphagnum- and litter-dominated forest floor vegetation, and proportion of silt in the mineral soil, and decreased with fire frequency in site 1, feathermoss- and lichen-dominated forest floor vegetation and increasing slope. Our results emphasize that boreal forest surface soil C stocks are highly variable in size across fine spatial scales, shaped by an interplay between historical forest fires, ecosystem productivity, forest floor vegetation, and hydro-topography. [ABSTRACT FROM AUTHOR]

Bryophytes are a dominant and functionally important component of the forest floor vegetation in boreal forests, yet little is known about the fungal diversity associated with these abundant plants. Using molecular identification, we document an ecologically and phylogenetically diverse array of fungi associated with the living parts of three widespread and abundant boreal forest bryophytes, i.e., Hylocomium splendens (Hedw.) Schimp. in B.S.G., Pleurozium schreberi (Brid.) Mitt., and Polytrichum commune Hedw. From 376 cloned ITS sequences, 158 operational taxonomic units (OTUs), roughly corresponding to the number of species, were defined based on sequence similarity searches (Fasta) and phylogenetic analyses. A main portion (62.8%) of the OTUs belonged to Ascomycota, 32.0% to Basidiomycota, 3.9% to Chytridiomycota, and 1.3% to Glomeromycota. The most common orders were Helotiales (18.6%), Agaricales (11.5%), Chaetothyriales (9.6%), and Tremellales (9.0%). Frequently detected OTUs of potentially high ecologic importance included two with high sequence similarity (>99%) to the agaric Entoloma conferendum (Britzelm.) Noordel and the endophyte Lophodermium piceae (Fckl.) Hoehn., and various OTUs with affinity to the Helotian genus Hyphodiscus. Several ectomycorrhiza-forming basidiomycetes were also detected. Most OTUs (77.2%) were only detected once and a very small overlap in composition of OTUs was observed among the three bryophytes, indicating the occurrence of an immense fungal diversity associated with boreal forest bryophytes that deserves further study. Key words: bryophytes, boreal forest, endophytes, environmental sampling, rRNA ITS sequence, moss. Les bryophytes constituent une part importante dominante et fonctionnelle de la vegetation des parterres forestiers en foret boreale, pourtant on connait peu de choses sur la diversite fongique associee a ces plantes abondantes. A l'aide de l'identification moleculaire, les auteurs ont etudie un ensemble ecologiquement et phylogenetiquement diversifie de champignons associes aux parties vivantes de trois bryophytes abondantes et largement distribuees dans la foret boreale, soient les Hylocomium splendens (Hedw.) Schimp. in B.S.G., Pleurozium schreberi (Brid.) Mitt. et Polytrichum commune Hedw. A partir de 376 sequences ITS clonees et en appliquant des recherches de similarite de sequences (Fasta) et des analyses phylogenetiques, les auteurs ont defini 158 unites taxonomiques operationnelles (OTU's) correspondant en gros au nombre d'especes. La majorite (62,8%) des OTU's appartiennent aux Ascomycota, 32,0% aux Basidiomycota, 3,9% aux Chytridiomycota et 1,3% aux Glomeromycota. Les Helotiales (18,6%, les Agaricales (11,5%), les Chaetothyriales (9,6%) et les Tremellales, constituent les principaux ordres. Parmi les OTU's de grande importance ecologique frequemment reperes on en retrouve deux avec forte ressemblance de sequences (>99%) avec l'agaric Entoloma conferendum (Britzelm.) Noordel et l'endophyte Lophodermium piceae (Fckl.) Hoehn., ainsi que divers OTU's ayant des affinites avec les Helotiales du genre Hyphodiscus. On retrouve egalement plusieurs basidiomycetes mycorhiziens. La plupart des OTU's n'apparaissent qu'une seule fois (72,2%) et on observe un tres faible recouvrement des OTU's pour l'ensemble des trois bryophytes, ce qui indique le besoin de poursuivre les etudes sur l'immense diversite fongique associee aux bryophytes de la foret boreale. Mots-cles : bryophytes, foret boreale, endophytes, echantillon environnemental, sequence rARN ITS, mousse., Introduction Bryophytes are dominating constituents of the forest floor vegetation in boreal forests, which make up the world's second largest terrestrial biome covering ca. 1.4 x [10.sup.7] [km.sup.2] of the [...]

Abstract: We investigated soil microbial community structure by phospholipid fatty acid (PLFA) analysis in a mature boreal spruce forest landscape in southern Norway, with low diversity of vascular plants. We [...]

Polyploid species possess more than two sets of chromosomes and may show high gene redundancy, hybrid vigor, and masking of deleterious alleles compared to their parent species. Following this, it is hypothesized that this makes them better at adapting to novel environments than their parent species, possibly due to phenotypic plasticity. The allopolyploid Arabidopsis suecica and its parent species A. arenosa and A. thaliana were chosen as a model system to investigate relationships between phenotypic plasticity, fitness, and genetic variation. Particularly, we test if A. suecica is more plastic, show higher genetic diversity, and/or have higher fitness than its parent species. Wild Norwegian populations of each species were analyzed for phenotypic responses to differences in availability of nutrient, water, and light, while genetic diversity was assessed through analysis of AFLP markers. Arabidopsis arenosa showed a higher level of phenotypic plasticity and higher levels of genetic diversity than the two other species, probably related to its outbreeding reproduction strategy. Furthermore, a general positive relationship between genetic diversity and phenotypic plasticity was found. Low genetic diversity was found in the inbreeding A. thaliana. Geographic spacing of populations might explain the clear genetic structure in A. arenosa, while the lack of structure in A. suecica could be due to coherent populations. Fitness measured as allocation of resources to reproduction, pointed toward A. arenosa having lower fitness under poor environmental conditions. Arabidopsis suecica, on the other hand, showed tendencies toward keeping up fitness under different environmental conditions. [ABSTRACT FROM AUTHOR]

Swamp forests in the boreal part of Sweden are dominated by Norway spruce (Picea abies). These forests typically grow on peat deposits with a water table that is often situated [...]

The analysis of pollen chemical composition is important to many fields, including agriculture, plant physiology, ecology, allergology, and climate studies. Here, the potential of a combination of different spectroscopic and spectrometric methods regarding the characterization of small biochemical differences between pollen samples was evaluated using multivariate statistical approaches. Pollen samples, collected from three populations of the grass Poa alpina, were analyzed using Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, surface enhanced Raman scattering (SERS), and matrix assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS). The variation in the sample set can be described in a hierarchical framework comprising three populations of the same grass species and four different growth conditions of the parent plants for each of the populations. Therefore, the data set can work here as a model system to evaluate the classification and characterization ability of the different spectroscopic and spectrometric methods. ANOVA Simultaneous Component Analysis (ASCA) was applied to achieve a separation of different sources of variance in the complex sample set. Since the chosen methods and sample preparations probe different parts and/or molecular constituents of the pollen grains, complementary information about the chemical composition of the pollen can be obtained. By using consensus principal component analysis (CPCA), data from the different methods are linked together. This enables an investigation of the underlying global information, since complementary chemical data are combined. The molecular information from four spectroscopies was combined with phenotypical information gathered from the parent plants, thereby helping to potentially link pollen chemistry to other biotic and abiotic parameters. [ABSTRACT FROM AUTHOR]