Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2026
Abstract
Schistidium arizonense is described as a new species from the US states of Arizona, New Mexico, and Texas. It belongs to section Atrofusca, but unlike most other taxa of the section, it is not a pure calcicole and also occurs on acidic substrates. The species is characterized by a combination of usually green coloration, fusiform perichaetia, perforated and fragile peristome teeth that are usually split in the upper part, flat or narrowly recurved leaf margins, and long-decurrent perichaetial leaf hairpoints. Based on sequences of the ITS region, the taxon is closely related to S. helveticum, which is congruent with morphological similarities, including similar size, the lack of stomata, and mostly absent or short hairpoints on vegetative leaves. Schistidium arizonense is, however, most likely to be confused with the widespread and highly variable S. crassipilum, which appears to be more distantly related.
Authors
Stefano Puliti Binbin Xiang Maciej Wielgosz Eivind Handegard Nicolas Cattaneo Marta Vergarechea Terje Gobakken Juha Hyyppä Erik Næsset Mikko Vastaranta Tuomas Yrttimaa Rasmus AstrupAbstract
Accurately determining the age of individual trees is important for understanding forest dynamics, tree growth, site productivity and describing ecological processes. Traditional methods, such as dendrochronological coring, are invasive, labor-intensive, and costly. This study investigates the use of deep learning (DL) to predict tree age from high-density laser scanning data as a scalable, non-invasive alternative. The dataset includes approximately 1700 tree point clouds from approx. 1 K trees across Norway, Sweden, and Finland, encompassing Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) and a broad range of tree age and developmental stages, from young seedlings (1 year) to old trees (∼350 years). Data were collected using terrestrial, mobile, and high-density airborne laser scanning platforms, enabling the development of sensor-agnostic models. We evaluated multiple modelling approaches, from linear regression to transformer architectures, using both training-from-scratch and fine-tuning strategies. Models fine-tuned starting from pre-trained weights from ForestFormer3D's U-Net as well as the transformer architecture (PointTransformerV3) trained from scratch, proved effective for age regression (RMSE ≤23 years). Although our analysis was limited to two tree species, we demonstrated that a single joint age-estimation model can be successfully trained for both species. We demonstrate that models trained on high-resolution data can generalize to lower-resolution, less costly inputs, provided that data augmentations that mimic reduced resolutions are included during training. This study presents a data-driven framework for estimating tree age without destructive sampling. The findings support the potential for AI-based methods to complement or replace traditional age estimation techniques in forest inventory and monitoring.
2025
Authors
Ken Olaf StoraunetAbstract
No abstract has been registered
Abstract
Schistidium pratense and S. heribertii, two distinctive and locally abundant components of the Alpine flora, are here formally described as new species from Europe. Although recognised for over two decades, their official taxonomic treatment has been long overdue. This paper provides an integrative account, combining morphological and molecular evidence, outlining their currently known distribution, and discussing their relationships to related species. Schistidium pratense is closely allied to S. dupretii in both molecular and morphological traits but differs in its larger overall size, including longer shoots and leaves, as well as in the absence of stomata. Schistidium heribertii resembles S. atrofuscum in its black coloration but is distinguished by its prominent leaf hairpoints and a pruinose appearance on the upper parts of the shoots. Molecular analyses place S. heribertii as the sister species to the clade comprising S. atrofuscum and S. helveticum. Both new species share similar ecological preferences, typically colonising calcareous substrates. Schistidium pratense is widespread and locally abundant in subalpine pastures, while S. heribertii has a more scattered distribution and predominantly inhabits warm sites across a broad elevational range in valleys with a continental climate. To date, S. heribertii is known only from the Alps, whereas S. pratense has also been recorded in Scandinavia, the Dinarides, the Apennines and the Black Forest in Germany
Authors
Gry Alfredsen Michael Altgen Mari S. Austigard Johan Mattsson Maria Nunez Lone Ross Sverre Aarseth Tunstad Andreas Treu Igor A. Yakovlev Nanna Bjerregaard PedersenAbstract
A total of 212 iconic wooden cable car pylons were constructed for mining operations in Svalbard, significantly contributing to Longyearbyen's historical identity as a mining town. Fieldwork in Svalbard involved collecting wood samples from 22 of these pylons, targeting wood exposed both aboveground and ground proximity. While the timber used in the constructions was assumed to be untreated Norway spruce (Picea abies), light microscopy revealed that 25% of the timber members were Scots pine (Pinus sylvestris). Wooden beams exposed aboveground showed initial decay over the first 80-90 years, whereas severe fungal decay was observed after about 50 years in wooden poles inserted in the ground. Metabarcoding identified Ascomycetes and Basidiomycetes to be predominating in the wood samples and unveiled new fungal species for Svalbard, including four brown rot, five white rot, and sixteen soft rot species. Macroscopic and microscopic examinations confirmed more advanced decay in ground proximity samples, dominated by brown and soft rot fungi.
Authors
Ignacio Sevillano Aksel Granhus Clara Antón Fernandéz Heleen de Wit Fride Høistad Schei Rannveig Margrete Jacobsen Ulrika Jansson Asplund Heikki Korpunen Christian Wilhelm Mohr Jenni Nordén Jørund Rolstad Svein Solberg Ken Olaf Storaunet Marta VergarecheaAbstract
There is an increasing interest in continuous cover forestry (CCF) as an alternative to clearcutting to promote multi-objective forests and preserve continuous maintenance of forest cover. Here, we assessed the effect that an increased use of CCF harvesting methods (shelterwood and selection cutting) in Norwegian forests can have on carbon sequestration. Thus, we simulated CO2 uptake in Norwegian forest stands throughout the 21st century under three scenarios that represent different levels of clearcutting and CCF harvesting methods, keeping the annual harvest volumes constant across all scenarios. The three scenarios are: 1) Business-as-usual (reference scenario where 3.5% of the harvested volume is obtained using CCF harvesting methods); 2) Harvested volume using CCF harvesting methods is increased to 15%; 3) Harvested volume using CCF harvesting methods is increased to 25%. Increasing the proportion of CCF would increase CO2 removals in the long-term (2100), resulting in an additional uptake of nearly 32 and 24 Tg CO2 when increasing CCF up to 25% and 15%, respectively. However, the simulations also showed that to be able to harvest the same timber volume as in the reference scenario that reflects current practice, an increased proportion of CCF would also require logging on a larger proportion of the forest area. CCF could have also positive implications for certain aspects of biodiversity, such as species that require shaded conditions, but harvesting across a larger total area could negatively impact other animals, plants and fungi.
Authors
Gry Alfredsen Michael Altgen Mari S. Austigard Johan Mattsson Maria Nunez Lone Ross Sverre Aarseth Tunstad Andreas Treu Igor A. Yakovlev Nanna Bjerregaard PedersenAbstract
This study uses a novel combination of DNA metabarcoding, light microscopy, decay rating, moisture dynamics, and chemical analysis to investigate wood decay in cultural heritage cable car pylons in Svalbard. Uniform design but varying ages allowed analysis of time-dependent decay. Light microscopy revealed the use of both Picea abies and Pinus sylvestris . Decay progressed more rapidly near ground contact, influencing density, lignin, and holocellulose content, with lignin increasing over time. DNA metabarcoding and microscopy revealed dominant brown and soft rot fungi, with greater fungal diversity near ground level. Several new fungal species were identified for Svalbard and the polar regions. In the context of climate change, this highlights the global importance of monitoring fungal decay in wooden structures. The study emphasises the need for updated species lists and continuous monitoring, as new fungi may affect conservation strategies. The interdisciplinary method offers deeper insight into microbial interactions than single-method approaches.
Authors
Niklas Lönnell Kristian Hassel Irina Goldberg Sanna Huttunen Ágúst H. Bjarnason Hans Blom Tomas Hallingbäck Lars Hedenäs Torbjørn Høitomt Kati Pihlaja Tommy Prestø Kimmo Syrjänen Lars Söderström Tauno Ulvinen Henrik WeibullAbstract
We present an updated checklist for all bryophyte species known to occur in the Nordic countries and list occurrences for each taxon from Iceland, the Faroe Islands, Denmark, Svalbard, Jan Mayen, Norway (mainland), Sweden and Finland. Altogether 1276 bryophyte species are included for the region. The checklist includes vernacular names in Icelandic, Danish, Norwegian, Swedish and Finnish. The following new nomenclatural combinations are proposed: Scapania scandica var. parvifolia comb. nov., Andreaea alpina var. hartmanii comb. nov., Didymodon islandicus comb. nov., Ephemerum serratum var. stoloniferum comb. nov., Hygroamblystegium varium var. fluviatile comb. nov., Hygroamblystegium varium var. tenax comb. nov., Ptychostomum arcticum var. purpurascens comb. nov., Ptychostomum intermedium var. nitidulum comb. nov. and Ptychostomum warneum var. mamillatum comb. nov.
Authors
Vilde Lytskjold Haukenes Johan Asplund Line Nybakken Jørund Rolstad Ken Olaf Storaunet Mikael OhlsonAbstract
A key property of the boreal forest is that it stores huge amounts of carbon (C), especially belowground in the soil. Amounts of C stored in the uppermost organic layer of boreal forest soils vary greatly in space due to an interplay between several variables facilitating or preventing C accumulation. In this study, we split C stocks into the organic layer and charcoal C due to their difference in origin, stability, and ecological properties. We compared organic layer C and charcoal C stocks in two regions of south-central Norway (Trillemarka and Varaldskogen), characterized by Scots pine and Norway spruce forests with varying fire histories. We used structural equation modeling to investigate how vegetation composition, hydrotopography, and soil properties interplay to shape organic layer C and charcoal C stocks. Pine forests consistently contained larger organic layer C stocks than spruce forests. Charcoal stocks, in contrast, were less consistent across both forest types and study regions as pine forests had higher charcoal C stocks than spruce forests in Trillemarka, while the two forest types contained equal charcoal C stocks in Varaldskogen. Charcoal and soil organic layer C stocks increased with higher fire frequencies (number of fire events over the last 600 years), but not with a shorter time since last fire (TSF). Additionally, vegetation composition, terrain slope, and soil moisture were the most important drivers of the organic layer C stocks, while charcoal C stocks were mainly controlled by the depth of the organic layer. Also, microtopography was of importance for organic layer C and charcoal C, since depressions in the forest floor had more charcoal C than well-drained minor hills.
Abstract
1. The results of nature restoration efforts have been characterized as notoriously unpredictable. Many variables impact the trajectory of species communities towards recovery, and ecological theory that takes traits, habitat configuration and scale into account, can improve models. However, the most important questions regarding the predictability of species community restoration may be related to stochasticity. 2. We investigated the assembly of a cyanolichen community in a chronosequence consisting of 88 new forest patches (30–140+ years old) comprising today 0.4% of a 170 km2 former treeless heathland area in south-western Norway. Two complete inventories were carried out 12 years apart, and we (1) tested inferences on colonization status and recovery time based on the first inventory only; (2) investigated the recovery of the lichen community by changes in species richness, species density and composition at three different spatial scales; and (3) discussed how dispersal capacity and stochasticity affect community recovery in general. 3. Colonization of sites by lichen species exceeded extinctions in young sites but not in old sites, and in the second inventory, the richness of species weighed by occurrences no longer differed significantly between young and old sites at landscape scale. However, the differences between old and young sites depended on the spatial scale and method of measurement. 4. In accordance with inferences based only on the first inventory, colonization and extinction dynamics indicated that recovery of species richness in our study system will take 90–120 years at the landscape scale, whereas recovery of species composition was difficult to determine due to idiosyncratic development among sites. 5. Synthesis and applications. Using species composition as a template for the evaluation of restoration recovery in systems with a high degree of stochastic colonization and extinction is problematic, particularly at finer scales. Ideally, comparisons of restoration and reference communities should therefore be at large enough spatial scale to cancel out the major effects of stochasticity at finer scales. Furthermore, we suggest that a complete recovery of species numbers may not be needed as an indicator of restoration success if species richness measurements indicate that communities are en route to recovery.