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.
2025
Abstract
Fine-scale, spatially explicit forest attribute maps are essential for guiding forest management and policy decisions. Such maps, based on the combination of National Forest Inventory (NFI) and remote sensing datasets, have a long tradition in the Nordic countries. Harmonizing the pixel size among national forest attribute maps would considerably improve the utility of the maps for users. However, the maps are often aligned with the NFI plot size, and the influence of creating these maps at different spatial resolutions (i.e. pixel sizes) is little studied. We assess the stand-level uncertainty (RMSE) of biomass, volume, basal area, and Lorey’s height estimates resulting from the aggregation of maps across varying spatial resolutions. Models fit at 16 m native resolution using more than 14 000 NFI plots were applied for predictions at pixels sizes (side lengths) of 1, 5, 10, 16, and 30 m. For independent validation, we used more than 600 field plots – that cover a total area of 24 ha and were clustered within 65 stands across Norway. For all attributes, the lowest RMSEs, ranging from 6.86% for Lorey’s height to 13.86% for volume, were observed for predictions at pixel sizes of 5 m to 16 m. The RMSE changes across resolutions were generally small (< 5%) for biomass, volume, and basal area. For Lorey’s height, changing the spatial resolution resulted in large RMSEs of up to 25%. Overall, our findings suggest that the main forest attributes can be mapped at a finer resolutions without complex adjustments.
Authors
Zsofia KomaAbstract
No abstract has been registered
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No abstract has been registered
Authors
Laura Jaakola Katja Karppinen N. Nguyen S. Jokipii-LukkariAbstract
Fruit ripening is a highly coordinated and complex process determining a wide range of characteristics affecting the fruit quality, such as flavour, nutritional value, shelf-life, and processing properties. The fruit set occurs after fertilization, followed by first an active cell division and a later cell expansion phase leading to ripening, which coincides with seed maturation. The ripening phase is regulated by a signalling network of thousands of genes that orchestrate the softening, and the accumulation of the secondary compounds and sugars in ripe fruits. Plant hormones, especially ethylene and abscisic acid (ABA) have major roles in the control of the ripening processes. Based on the burst of respiration rate and ethylene production and/or the peak in ABA production at the onset of ripening, fruits are classified as climacteric or non-climacteric fruits, respectively. We have studied the regulation of ripening in bilberry (Vaccinium myrtillus L.), traditionally classified as non-climacteric fruits, by analysing the role of the plant hormones, transcription factors, and the structural genes controlling the anthocyanin accumulation and the cell wall softening during the berry ripening. Our results have identified some upstream regulators of fruit ripening in bilberry and provided new knowledge on the R2R3 MYB and basic helix-loop-helix (bHLH) transcription factors, which are the key regulators of anthocyanin biosynthesis. Moreover, we have shown evidence of the role of ABA in controlling the ripening related anthocyanin accumulation in bilberry. Our recent results on metabolomic and proteomic profiling of bilberry indicate an increase in ethylene biosynthesis during bilberry fruit development coinciding with the ABA peak, raising a need for further studies and clearer determination between the classification of climacteric and non-climacteric fruits.
Abstract
Climate change is expected to increase the frequency and severity of natural disturbances. In Nordic conifer forests, damage caused by snow accumulation in the canopy is one of the most significant disturbance agents. This study investigates whether adaptive forest management can enhance resistance to snow damage, using a large forest property in southeastern Norway as a case study. To achieve this, we extended the existing scenario analysis tool, GAYA 2.0, integrating new functionality to analyze the risk of snow damage. We performed scenario simulations using a mechanistic critical snow load model to compare two alternative management strategies: standard management and an adapted management approach that reduces stand density in regeneration and tending phases. We analyzed and compared the management effects on snow damage resistance and probability, and on long-term forest production and income. The results indicate that reduced density management leads to a 2.02 % increase in critical snow load (from 74.19 Kg m-2 to 75.68 Kg m-2), and a 10.42 % reduction in yearly damage probability (from 0.345 % to 0.308 %). These findings suggest that adaptive management practices by reducing stand density can effectively enhance resistance and mitigate risks associated with snow damage in Nordic boreal forest ecosystems. The reduced stand density management does not have a significant impact on long-term production and income levels.
Authors
Stig Strandli GezeliusAbstract
How do provisions for administrative sanctioning affect the implementation of loose legal norms? To streamline regulation, governments have increased their penal capacity by authorizing administrative sanctioning, and they have decentralized regulatory responsibility by loosening legal norms. A case study of Norway's animal welfare governance shows how using administrative sanctions to enforce loose legal norms led to unpredictable sanctioning and, thereby, subverted regulatees' trust in law enforcement. Ensuing resistance from regulatees pressured inspectors to regain legitimacy by tightening loose legal norms and by backing down on administrative sanctioning. Inspectors thus reversed streamlining policies to protect the primary purpose of their profession: to motivate compliance with animal welfare law. The case highlights unintended consequences of streamlining regulation. It also illustrates how frontline workers may protect their primary purpose by disregarding policies they perceive as disruptive.
Abstract
The objective of this study was to demonstrate how height growth recalculated to periodic site index could be used to monitor and identify climatic drivers for growth variations. We used data from Norway’s National Forest Inventory (NFI), with attention to Norway spruce in the lowlands (<500 m a.s.l.) of southeastern Norway. We recalculated height growth to periodic site index and extracted a time series with annual values. We supplemented this with climatic data, i.e. monthly mean temperature, precipitation and deMartonne aridity index. The results showed that a characteristic two-peaked time series in volume growth in Norway 1994–2020 corresponded well to a time series of periodic site index for Norway spruce in the specific region mentioned above. Statistical analyses showed that for spruce, the periodic site index was higher in cold and moist summers than in warm and dry. Spruce mortality in this region tripled during 2012–22 when June temperature increased considerably, while periodic site index decreased. This corroborates warm and dry weather in June to be a main stress factor for spruce. In conclusion, periodic site index has a potential for being implemented for monitoring site productivity and for identification of climatic drivers.
Authors
Eirik Næsset Ramtvedt Ryan Bright Terje Gobakken Adrián Cidre-González Maja K. Sundqvist Zsofia R. Stangl Marie Charlotte Nilsson Daniel B. Metcalfe Michael J. GundaleAbstract
There is a public debate on how boreal forests can deliver climate change mitigation benefits. While most debates regarding Fennoscandian forests have centered on the contrasting effects of actively managed and old-growth unmanaged forests on carbon uptake and storage, the impact of surface albedo has often been overlooked. According to the new EU forest strategy for 2030, with aim of improving quantity and quality of forests by promoting primary old-growth forests and avoiding clear-cutting, among others, we examined how albedo across a wide age range of boreal Pinus-dominated forests develops over time after wildfire (defined as unmanaged) and clear-cutting (defined as managed). We find that albedo decreases over time after disturbance, but mainly in managed forests. Annual mean albedo in young (<30 years) managed forests (0.36±0.04) is markedly larger than in young unmanaged forests (0.18±0.04). This difference is particularly prominent during winter, when snow-covered ground is present. The mean albedo over the entire unmanaged forest-age gradient (0.17±0.05) is significantly lower (p < 0.05) than that of the managed forest-age gradient (0.23±0.10). Considering the typically higher frequency of clear-cuts compared to wildfires in Fennoscandian forests, these albedo differences would be even larger over long time scales. Our findings reveal the importance of considering the climatic cooling potential of albedo when making decisions on how to optimize future forest management in northern boreal forests to mitigate climate change.
Abstract
No abstract has been registered
Abstract
Plants in raingardens are important for evapotranspiration and maintaining infiltration properties. Hydrological conditions, however, fluctuate between dry and saturated, strongly affecting plant performance and limiting plant selection in design. This study experimentally assessed whether fluctuating hydrology impacts growth, flowering, and root morphology in the drought-tolerant Knautia arvensis and the wet-tolerant Lythrum salicaria. The hydrological regimes included repeated cycles of dry and wet conditions: Drought regime with cycles of a drought period followed by a single watering; Flooding regime with cycles of 72-hour flooding and a 48-hour drained period; and a subsequent Drought+Flooding regime with cycles of 72-hour flooding followed by a drought period. Knautia reduced growth under flooding cycles, while Lythrum reduced growth and flowering under drought cycles. Repeated consecutive drought and flooding cycles negatively influenced the growth of both species in the same way, with flooding affecting Knautia and drought affecting Lythrum. Lythrum showed more plasticity than Knautia, allocating more biomass to roots during drought cycles. Flooding cycles reduced root length in Knautia, while the drought cycles and consecutive Drought+Flooding cycles increased root diameter and decreased root length in Lythrum. Both species had coarse roots (> 2 mm) to support infiltration through biopores. If we assume that raingardens have free drainage and only rarely flood, drought-tolerant traits are more important. However, wet-tolerant species can benefit the system, especially through higher water use. This research contributes to the ecological understanding of plant responses to fluctuating hydrology, enabling a better plant selection for effective raingardens.