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
In terrestrial ecosystems, forest stands are the primary drivers of atmospheric moisture and local climate regulation, making the quantification of transpiration (T) at the stand level both highly relevant and scientifically important. Stand-level T quantification complements evapotranspiration monitoring by eddy-covariance systems, providing valuable insight into the water use efficiency of forested ecosystems in addition to serving as important inputs for the calibration and validation of global transpiration monitoring products based on satellite observations. Stand level T estimates are typically obtained by scaling up individual tree estimates of water movement within the xylem – or sap flow. This movement affects the radius of a tree stem, whose fluctuations over the diel cycle provide pertinent information about tree water relations which can be readily detected by point (or precision) dendrometers. While sap flow measurements have greatly advanced our understanding of water consumption (T) at the level of individual trees, deploying conventional sap flow monitoring equipment to quantify T at the level of entire forested stands (or ecosystems) can quickly become costly since sap flow measurements from many trees are required to reduce the uncertainty of the upscaling. Using a boreal old-growth Norway spruce stand at an ICOS site in Southern Norway as a case study, we assess the potential of augmenting conventional sap flow monitoring systems with sap flow modeling informed by point dendrometer measurements to reduce the uncertainty of stand level T estimation at the daily resolution. We test the hypothesis that the uncertainty reduction afforded by a boosted tree sample size more than offsets the propagation of uncertainty originating from the point dendrometer-based sap flow estimates.
Abstract
• Definitions of continuous cover forestry (CCF) vary among countries, and are often a political compromise. • We offer a common definition of CCF for this book, which can be found in a text box below. • The three silvicultural systems included in CCF are described briefly. • Conversion to CCF will be an important activity in the near future, but approaches to and experiences of conversion to CCF are largely lacking in Fennoscandia. • Methods need to be developed for how to assess the suitability of forest stands for CCF or conversion to CCF. • Bad practices and experiences with selective cutting in Fennoscandia before 1950 have led to a loss of experience and willingness to apply CCF. • Climate adaptation will make it necessary to modify CCF approaches in the region, especially given the limited number of shade-tolerant species. • In this book we summarize peer-reviewed scientific articles and research reports from Finland, Sweden, and Norway on continuous cover forestry (CCF), i.e. forestry without clearcutting • This book originates from growing interest in CCF among various stakeholders, and aims to promote discussion, further research, and inform decision-makers • The book targets those interested in boreal forests, forest management, and ecosystem services • In this chapter we review the background to the use of CCF and the reasons that led to its prohibition and subsequent resurgence in the Nordic countries
Authors
Mikolaj Lula Kjersti Holt Hanssen Martin Goude Hannu Hökkä Sauli Valkonen Andreas Brunner Pasi Rautio Charlotta Erefur Aksel GranhusAbstract
• In the context of continuous cover forestry (CCF), natural regeneration is the preferred form of regeneration, but it is a long-lasting and complex process. Shelter density has a large effect on the regeneration process and results. • The selection system, particularly suited for shade-tolerant species like Norway spruce, relies on continuous regeneration and ingrowth into larger size classes. Regeneration and ingrowth rates vary significantly among stands, influenced by site and historical factors, with no clear relationship to current stand conditions. • In the group system, edge trees influence regeneration by providing seeds, checking weed growth, and exerting competition. Regeneration in gaps is generally satisfactory for both Norway spruce and Scots pine. However, seedlings usually grow slower, especially close to the gap edges. • The shelterwood system promotes regeneration through a successive, uniform opening of the canopy. Shelter trees provide seeds, and reduce seedling damage and competition from ground vegetation. On the other hand, the remaining overstorey shelter trees reduce seedling growth. • Conversion to the selection system initiates regeneration in young stands, aiming for slow and steady regeneration. Given the rapid growth and crown closure in young stands, frequent manipulation of shelter density is essential during conversion, for example by opening small gaps.
Authors
Simone Bianchi Andreas Brunner Kjersti Holt Hanssen Hannu Hökkä Urban Nilsson Nils Fahlvik Jari HynynenAbstract
• There is still a lack of knowledge on growth and yield (G&Y) in continuous cover forestry (CCF). Most published studies are on the selection system with Norway spruce. • Published comparisons of the selection system with rotation forestry (RF) show contrasting results. Generally, there seems to be a trend toward faster stand growth in RF. • However, there are many uncertainties due to several confounding factors, such as stand-density effects, site-quality classification, and/or growth models used. Most studies do not properly account for all these factors, making it difficult to generalise their results. • The optimal stand density trade off for the selection system between stand growth and recruitment should be better investigated. Preliminary results show this could strongly affect stand growth. • There is even less knowledge related to G&Y during conversion, a potential bottleneck for full implementation of CCF in the region.
Authors
Mekjell Meland Oddmund Frøynes Darius Kviklys Uros Gasic Uroš Gašić Tomislav Tosti Milica Fotiric AksicAbstract
No abstract has been registered
Abstract
Biochar is a carbon-rich solid residual material produced by pyrolysis of organic material. In the pyrolysis, organic material is heated at 250°C–700°C under low oxygen concentrations, as a result of which heat energy, bio-oil, fuel gas products, and biochar will be gained. The most common production methods are slow pyrolysis, fast pyrolysis, gasification, torrefaction, and hydrothermal carbonization. Biochar can be produced from a variety of organic materials, such as wood, agricultural crop residues, municipal wastes, manure, and food wastes. Feedstocks from forests and forestry may include bark, sawdust, and shavings from different tree species or tree parts, such as from harvest residues (branches and tops) and small diameter wood. Biochar can be used in several applications, such as soil amendment in agriculture and forestry, carbon sequestration, water purification, and soil remediation. Biochar has a long history in the use of soil conditioner since it has been utilized in the Amazon Basin of South America for more than 2500 years. These fertile, very productive soils are called Terra Preta, the black soil of the Indians or Amazonian dark earth. Terra Preta soils contain burned wood, crops and bones, and they have high carbon and nutrient content. Biochar has caught great attention over the last decade, yielding large number of scientific publications and many research advances. Biochar use has been studied extensively in agricultural soils. Much less research data are available from forest ecosystems, but the number of studies has rapidly increased in the recent years.
Abstract
Post-Consumer Wood (PCW) is a valuable resource that could substitute virgin wood in many applications. However, its integration into the wood processing chain requires detailed information on composition, content of contaminants, size, and shape. Here, PCW collected over eight months from three sorting facilities in southeastern Norway was analyzed for suitability in recycling. Shredded PCW from 24 samples was manually sorted based on material origin, analyzed for heavy metal concentrations, and the particle geometry was measured with an automated laser scanner. Based on the results, 39–67 % of the mixed PCW was made up by clean wood particles suitable for recycling. Wood-based panels within the PCW were not only a source of contaminants (adhesives, coatings) but also decreased the length-to-width ratio of the resulting particles and chips. The median heavy metal concentrations did not exceed the limit values issued by the European Panel Federation. However, individual samples and the fine fraction (< 8 mm) exceeded these limit values. Manual pre-sorting before shredding into chips increased the share of clean wood particles, prevented elevated fiberboard contents and significantly reduced heavy metal concentrations.
Abstract
European canker developing in young apple orchards may have been initiated in the nursery. Artifcial inoculation of Neonectria ditissima was carried out at time of heading back and manipulating of branch angles in the second year of nursery phase sized trees of 10 apple cultivars, either T-budded or grafted (with or without interstem). The trees were followed for two growing seasons and canker was found on 10% of the trees inoculated in wounds from heading back of the top shoots and on 24% of the trees inoculated in cracks from bending side branches. About 50% of those trees had visible cankers after the frst growing season, clearly showing the risk of delivering non-symptomatic trees to customers when infected in year two of the nursery phase. Commercial trees of six cultivars were inoculated either in wounds (cut surfaces or cracks from bending), or on nonwounded trees at the time of planting and followed for two growing seasons. Inoculation in crack wounds from bending side branches resulted in a higher number of infected trees than cut surfaces, and both had a signifcantly higher incidence than non-wounded inoculated trees and their non-inoculated controls (97%, 67%, 14%, and 3 to 5%, respectively). All trees with canker after two growing seasons had symptoms after the frst growing season. After two growing seasons, 50% of the trees with an infected scion had canker lesions on the rootstock. These results show that cankers discovered during the year of planting could have been newly initiated infections if the trees had been wounded and exposed to inoculum at planting.
Authors
Anders Bryn Rune Halvorsen Peter Horvath Lasse Torben Keetz Ida Marielle Mienna Trond Simensen Olav Skarpaas Ingrid Vesterdal Tjessem Joachim Paul Töpper Vigdis Vandvik Liv Guri Velle Catharina Caspara VloonAbstract
No abstract has been registered
Abstract
Pedunculate oak (Quercus robur L.) is widely distributed across Europe and serves critical ecological, economic, and recreational functions. Investigating its responses to stressors such as drought, extreme temperatures, pests, and pathogens provides valuable insights into its capacity to adapt to climate change. Genetic and dendrochronological studies offer complementary perspectives on this adaptability. Tree-ring analysis (dendrochronology) reveals how Q. robur has historically responded to environmental stressors, linking growth patterns to specific conditions such as drought or temperature extremes. By examining tree-ring width, density, and dynamics, researchers can identify periods of growth suppression or enhancement and predict forest responses to future climatic events. Genetic studies further complement this by uncovering adaptive genetic diversity and inheritance patterns. Identifying genetic markers associated with stress tolerance enables forest managers to prioritize the conservation of populations with higher adaptive potential. These insights can guide reforestation efforts and support the development of climate-resilient oak populations. By integrating genetic and dendrochronological data, researchers gain a holistic understanding of Q. robur’s mechanisms of resilience. This knowledge is vital for adaptive forest management and sustainable planning in the face of environmental challenges, ultimately helping to ensure the long-term viability of oak populations and their ecosystems. The topics covered in this review are very broad. We tried to include the most relevant, important, and significant studies, but focused mainly on the relatively recent Eastern European studies because they include the most of the species’ area. However, although more than 270 published works have been cited in this review, we have, of course, missed some published studies. We apologize in advance to authors of those relevant works that have not been cited.