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.
2024
Abstract
Hurdal (NO-Hur) is a recently labelled ICOS class 2 station in Southeast Norway. It represents a typical southern boreal forest of medium productivity, dominated by old Norway spruce (average tree height: 25 m, ages: up to 100 years) with some pine and broadleaved trees. The eddy covariance technique is used to measure CO2 fluxes on a 42 m tower since 2021 . The measurements have an average footprint area of approximately 63 ha. In 2023, the region experienced an unusual dry spring and then an extraordinary flood in August. Both events showed significant impact on the Net Ecosystem Exchange (NEE) and heat fluxes. The station is also equipped with automatic dendrometers and sap flow devices on the dominant spruce trees, allowing us to investigate the impact of these events at the individual tree scale. We will present tree growth and transpiration flux at different temporal scales (from sub-daily to seasonal), and relate these single tree observations with environmental variables, ecosystem-level NEE and evapotranspiration using phase synchronization analysis. These observational data will yield insights into carbon and water processes of a boreal forest at different scales in response to multiple disturbances.
Abstract
This study examined the economic potential of thinning in pure, even-aged Norway spruce and Scots pine forests in Norway based on simulated stand dynamics using plot data from the Norwegian national forest inventory. Simulated management scenarios included fully mechanized thinning from below of varying intensity including no thinning. The economic evaluation was based on comparing the equivalent annual annuity of the unthinned scenario and the economically best-performing thinning scenario for each studied plot. The findings suggest that only late thinnings in well-stocked stands with sufficiently large trees are economically beneficial. Furthermore, to be economically superior, a thinning intervention itself had to generate enough profit, meaning that the revenue from thinning needed to sufficiently exceed the costs. Profitability of thinning scenarios varied with discount rates and timber prices and depended on whether rotation age was based on maximum net present value or maximum mean annual increment. Thinning was less often profitable in pine compared to spruce stands. This study is among the few that model stand development considering post-thinning stand structures with systematic machine trails while assessing the profitability of such thinning operations.
Abstract
Forest age structure is one of the most important ecological indicators of forest sustainability in terms of biodiversity, forest history, harvesting potentials, carbon storage, and recreational values. The available information on the forest age is most often stand age from forest management plans or national forest inventories. Depending on the definition, stand age is often not a good indicator for the biological age of the dominant trees in a stand. Here, we used 6,998 increment cores from dominant Norway spruce (Picea abies L.) and Scots pine (Pinus sylvestris L.) sampled on National Forest Inventory (NFI) plots throughout Norway to gain a better understanding of the age structure of Norway spruce and Scots pine stands in Norway, and on the relationship between the recorded stand age and the biological age of dominant trees on the NFI plots. In forest with stand ages indicating that the stand was established after the abandonment of selective harvesting in favor of even-aged management dominated by clear-cutting methods (ca.1940 C.E.), we found no systematic difference between the biological age of the sampled trees and the stand age assessed by the NFI. In older stands, there was a large difference between the stand age and the age of the overstory trees with the sampled age trees occasionally being hundreds of years older than the stand age. Our study also reveals that the area of forest with old Norway spruce and Scots pine trees ≥ 160 years old is considerably higher than the corresponding area estimate based on information derived from the stand age only. These results are important as the stand age is often used to characterize status with respect to forest naturalness, biodiversity, guide protection efforts, and describe the appropriate and allowed management activities.
Abstract
No abstract has been registered
Abstract
Aim Seedling recruitment is a vital process for forest regeneration and is influenced by various factors such as stand composition, climate, and soil disturbance. We conducted a long-term field experiment (18 years) to study the effects of these factors and their interactions on seedling recruitment. Location Our study focused on five main species in boreal mixed woods of eastern Canada: trembling aspen (Populus tremuloides), paper birch (Betula papyrifera), white spruce (Picea glauca), balsam fir (Abies balsamea), and white cedar (Thuja occidentalis). Methods Sixteen 1-m2 seedling monitoring subplots were set up in each of seven stands originating from different wildfires (fire years ranging from 1760 to 1944), with a soil scarification treatment applied to every other subplot. Annual new seedling counts were related to growing-season climate (mean temperature, growing degree days and drought code), scarification, and stand effects via a Bayesian generalized linear mixed model. Results Soil scarification had a large positive effect on seedling recruitment for three species (aspen, birch and spruce). As expected, high mean temperatures during the seed production period (two years prior to seedling emergence) increased seedling recruitment for all species but aspen. Contrary to other studies, we did not find a positive effect of dry conditions during the seed production period. Furthermore, high values of growing degree days suppressed conifer seedling recruitment. Except for white cedar, basal area was weakly correlated with seedling abundance, suggesting a small number of reproductive individuals is sufficient to saturate seedling recruitment. Conclusion Our findings underscore the importance of considering multiple factors, such as soil disturbance, climate, and stand composition, as well as their effects on different life stages when developing effective forest management strategies to promote regeneration in boreal mixed-wood ecosystems.
Authors
Morgane MerlinAbstract
No abstract has been registered
Authors
Adam Kristensson Paul Miller Holger Lange Thomas Holst Jaana Bäck Pontus Roldin Natascha Kljun Anne Klosterhalfen Anders Ahlström Thomas A. Pugh Liesbet Vranken Mark Rounsevell Svein Solberg James AtkinsonAbstract
Forests are a key plank of European policies to mitigate and adapt to climate change and to promote biodiversity. These policies are starting to become more nuanced with respect to the account of their impacts on carbon storage, considering the effect of long-lived wood products and value of conserving old-growth forests, along with indirect land-use change impacts. However, a CO2-focused perspective means that many processes are still omitted for the quantification of the true extent of climate effects. Emissions of the greenhouse gases nitrous oxide and methane, short-lived climate forcers and effects from albedo changes and heat fluxes are also relevant. These processes are interconnected and influence the climate mitigation of forests in a complex way and need to be considered. The CLImate Mitigation and Bioeconomy pathways for sustainable FORESTry (CLIMB-FOREST) Horizon Europe project that runs until 2027 uses a holistic approach to estimate the climate impacts of various management alternatives. The foundation of CLIMB-FOREST is the use of European-wide empirical data, as well as an advanced coupled vegetation and earth-system modelling framework that includes biodiversity indicators and the interaction of forestry stakeholders in a global trade system. This framework is used to model management, forest tree species and climate on short- to long-term in Europe. We present first results of the climate effects and ecosystem functioning for a range of management alternatives in boreal, temperate, and Mediterranean forests. For example, introducing broadleaved trees in a coniferous forest promotes resilience and increased cooling from higher solar light scattering and latent heat flux of broadleaved trees. On the other hand, higher evapotranspiration might lead to an accelerated soil moisture depletion and reduced monoterpene emissions. The latter would have a warming effect because terpenes produce atmospheric particles, which are effective cooling agents through their involvement in cloud formation. Consequently, understanding these complex climate effects is key for appropriate climate-smart-forestry policies and approaches. The main outcomes and impacts of CLIMB-FOREST are to suggest alternative pathways for the forest sector to mitigate climate change in entire Europe, create attitude change in the policymaking process and influence foresters to adopt to new forest management strategies.
Authors
Ignacio SevillanoAbstract
No abstract has been registered
Authors
Johanna Lykke Sörensen Stephanie Eisner Jonas Olsson Stein Beldring Vanessa S.B. Carvalho Maria Elenius Carlos Ruberto Fragoso Jr Anna Hansen Trine Jahr Hegdahl Benedito C. Silva Michelle S. Reboita Daniela R.T. Riondet-Costa Nívea A.D. Pons Cintia B. UvoAbstract
Decision Support Indicators (DSIs) are metrics designed to inform local and regional stakeholders about the characteristics of a predicted (or ongoing) event to facilitate decision-making. In this paper, the DSI concept was developed to clarify the different aims of different kinds of indicators by naming them, and a framework was developed to describe and support the usage of such DSIs. The framework includes three kinds of DSI: hydroclimatic DSIs which are easy to calculate but hard to understand by non-experts; impact-based DSIs which are often difficult to calculate but easy to understand by non-experts; and event-based DSIs, which compare a current or projected state to a locally well-known historical event, where hydroclimatic and impact-based DSIs are currently mainly used. Tables and figures were developed to support the DSI development in collaboration with stakeholders. To develop and test the framework, seven case studies, representing different hydrological pressures on three continents (South America, Asia, and Europe), were carried out. The case studies span several temporal and spatial scales (hours-decades; 70–6,000 km2) as well as hydrological pressures (pluvial and riverine floods, drought, and water scarcity), representing different climate zones. Based on stakeholder workshops, DSIs were developed for these cases, which are used as examples of the conceptual framework. The adaptability of the DSI framework to this wide range of cases shows that the framework and related concepts are useful in many contexts.
Abstract
The decision support indicators (DSIs) are specifically designed to inform local and regional stakeholders on the characteristics of a predicted event to facilitate decision-making. They can be classified as conventional, impact-based and event-based DSIs. This study aims to develop methodologies for calculating event-based DSIs and to evaluate the usefulness of different classes of DSIs for climate impact assessment and climate actions by learning about users' perceptions. The DSIs are calculated based on an ensemble of hydrological projections in western Norway under two representative concentration pathway (RCP) scenarios. The definitions, methodologies and results of the indicators are summarized in questionnaires and evaluated by key stakeholders in terms of understandability, importance, plausibility and applicability. Based on the feedback, we conclude that the conventional DSIs are still preferred by stakeholders and an appropriate selection of conventional DSIs may overcome the understanding problems between the scientists and stakeholders. The DSIs based on well-known historical events are easy to understand and can be a useful tool to convey climate information to the public. However, they are not readily implemented by stakeholders in the decision-making process. The impact-based DSI is generally easy to understand and important but it can be restricted to specific impact sectors.