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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.

2022

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Abstract

Fishbones contain significant amounts of plant nutrients. Fish residues may be preserved by acidification to pH < 4, which may affect the chemical extractability, and the plant availability of nutrients when applied as fertilisers. Grinded bone material from cod (Gadus morhua) heads was mixed with formic acid to investigate if this would increase the concentrations of ammonium lactate–acetate (AL)-extractable nutrients. Two degrees of fineness of fishbones (coarse 2–4 mm; fine < 0.71 mm) were compared at pH 3.0 and 4.0 plus a water control in a laboratory study over 55 days. Samples for measurement of AL-extractable P, Ca, Mg and K were taken on day 2, 15, 34 and 55. Whereas more formic acid and thereby lower pH clearly increased the concentrations of AL-extractable calcium (Ca-AL) and magnesium (Mg-AL), AL-extractable phosphorus (P-AL) was only significantly increased in finely grinded bones at pH 3. After 34 days at pH 3, 6% of the total content of P was extracted by AL in fine fishbones. In the water control, about 1% of the P was extracted, possibly from phospholipids. This P-AL concentration was well above P-AL extracted from acidified coarse fishbones (pH 3 and 4) and from fine fishbones acidified to pH 4. With acidification, about 30% of total Ca and 100% of total Mg were extracted by AL, and the Ca-AL and Mg-AL concentrations were closely correlated. A possible reason for lower P-AL in coarse fishbones at pH 3 and 4, and in fine fishbones at pH 4 than in water controls may be a precipitation of apatite from phospholipids and dissolved calcium.

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Abstract

There is debate on which tree species can sustain forest ecosystem services in a drier and warmer future. In Europe, the use of non-native timber species, such as Douglas fir (Pseudotsuga menziesii [Mirb.] Franco), is suggested as a solution to mitigate climate change impacts because of their high growth resilience to drought. However, the biogeographical, climatic and ecological limits for widely planted timber species still need to be defined. Here, we study the growth response to climate variables and drought of four Douglas fir plantations in northern Spain subjected to contrasting climate conditions. Further, we measure wood density in one of the sites to obtain a better understanding of growth responses to climate. Correlative analyses and simulations based on the Vaganov–Shaskin process-based model confirm that growth of Douglas fir is constrained by warm and dry conditions during summer and early autumn, particularly in the driest study site. Minimum wood density increased in response to dry spring conditions. Therefore, planting Douglas fir in sites with a marked summer drought will result in reduced growth but a dense earlywood. Stands inhabiting dry sites are vulnerable to late-summer drought stress and can act as “sentinel plantations”, delineating the tolerance climate limits of timber species.

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Abstract

The British forestry sector lacks reliable dynamic growth models for stands of improved Sitka spruce, the most important commercial forest type in Great Britain. The aim of this study is to fill this gap by trialling a new modelling framework and to lay the foundations of a future dynamic growth simulator for that forest type. First, we present single tree diameter and height increment models that are climate sensitive and include explicit competition effects. The predictions from the increment models are pooled to project diameter and height at a given age. These projections are then used as inputs to an integrated taper model from which stochastic tree volume predictions are obtained. Retrospective data from over 1400 trees collected in two extensive genetic trials in Scotland and Wales were used for the purposes of this study. Diameter increment and height increment predictions were highly accurate and diameter and height projections proved consistent. The predicted volume at the time of harvesting also exhibited a high degree of accuracy, which shows the robustness of our approach. Further data will be needed in the future to recalibrate the present models and extend their range of validity to the whole of Great Britain.

Abstract

We present an innovative value chain on upscaling and commercial production of carbonized bio-briquettes from agro-industrial waste (mainly a sugarcane bagasse), that aims at substituting a forest-based charcoal for household consumption and thus reduce deforestation. We demonstrate the three main pillars of the value-chain: (1). Empowering and capacity building of members of the cooperatives (mainly women), through developing technical skills, using and maintaining technologies and tools, ergonomics and safety, businesses and marketing. (2). Innovative locally built biowaste to biofuel conversion technologies. This are technologies for raw material (biowaste) preparation (transport, drying and storage), locally developing carbonization kilns of high efficiency and commercial volume, biochar production, selection of bio-based binders, local fabrication of briquetting machines, production of briquettes, drying and storage of briquettes. This section demonstrates (using videos and pictures) on how a daily briquettes production of 3-tons is achieved, with briquette qualities comparable to that of wood-based charcoal. We also demonstrate production of custom-made cookstoves for briquettes by modifying existing local cookstoves. Further, we demonstrate the amount of avoided deforestation through such innovative local approaches. (3). Business and market development: This aims at bringing green-jobs to villages in sustainable supply, distribution, and sales of clean locally produced bio-briquettes. The program enables capacity building of members of the cooperatives in business and marketing; building partnership with key market segments and cooperation with private sector such as distributors, consumers, lenders and banks. The complete value-chain is a result of a successful development and partnership program (2018-2021) supported by the government of Norway that involved Kenyan national institutions, local community cooperatives and international partners.

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Abstract

In the context of global change, the integration of non-native tree (NNT) species into European forestry is increasingly being discussed. The ecological consequences of increasing use or spread of NNTs in European forests are highly uncertain, as the scientific evidence is either constraint to results from case studies with limited spatial extent, or concerns global assessments that lack focus on European NNTs. For either case, generalisations on European NNTs are challenging to draw. Here we compile data on the impacts of seven important NNTs (Acacia dealbata, Ailanthus altissima, Eucalyptus globulus, Prunus serotina, Pseudotsuga menziesii, Quercus rubra, Robinia pseudoacacia) on physical and chemical soil properties and diversity attributes in Europe, and summarise commonalities and differences. From a total of 103 publications considered, studies on diversity attributes were overall more frequent than studies on soil properties. The effects on soil properties varied greatly among tree species and depended on the respective soil property. Overall, increasing (45%) and decreasing (45%) impacts on soil occurred with similar frequency. In contrast, decreasing impacts on biodiversity were much more frequent (66%) than increasing ones (24%). Species phylogenetically distant from European tree species, such as Acacia dealbata, Eucalyptus globulus and Ailanthus altissima, showed the strongest decreasing impacts on biodiversity. Our results suggest that forest managers should be cautious in using NNTs, as a majority of NNT stands host fewer species when compared with native tree species or ecosystems, likely reflected in changes in biotic interactions and ecosystem functions. The high variability of impacts suggests that individual NNTs should be assessed separately, but NNTs that lack European relatives should be used with particular caution.

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Abstract

Mountain birch forest covers large areas in Eurasia, and their ecological resilience provides important ecosystem services to human societies. This study describes long-term stand dynamics based on permanent plots in the upper mountain birch belt in SE Norway. We also present forest line changes over a period of 70 years. Inventories were conducted in 1931, 1953, and 2007. Overall, there were small changes from 1931 up to 1953 followed by a marked increase in biomass and dominant height of mountain birch throughout the period from 1953 to 2007. In addition, the biomass of spruce (Picea abies) and the number of plots with spruce present doubled. The high mortality rate of larger birch stems and large recruitment by sprouting since the 1960s reveal recurrent rejuvenation events after the earlier outbreak of the autumnal moth (Epirrita autumnata). Our results demonstrate both a high stem turnover in mountain birch and a great ability to recover after disturbances. This trend is interpreted as regrowth after a moth attack, but also long-term and time-lagged responses due to slightly improved growth conditions. An advance of the mountain birch forest line by 0.71 m year−1 from 1937 to 2007 was documented, resulting in a total reduction of the alpine area by 12%. Most of the changes in the forest line seem to have taken place after 1960. Regarding silviculture methods in mountain birch, a dimension cutting of larger birch trees with a cutting interval of c. 60 years seems to be a sustainable alternative for mimicking natural processes.