Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2022
Forfattere
Pedro Caldas Britto Dirk Jaeger Stephan Hoffmann Renato Cesar Goncalves Robert Alexander Christian Vibrans Alfredo Celso FantiniSammendrag
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Forfattere
Antonio Gazol Cristina Valeriano Alejandro Cantero Marta Vergarechea Jesús Julio CamareroSammendrag
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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Forfattere
Thomas SolvinSammendrag
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Forfattere
Katharina HobrakSammendrag
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Forfattere
Belachew Gizachew ZelekeSammendrag
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.
Sammendrag
Tree diameter increment (ΔDBH) and total tree height increment (ΔHT) are key components of a forest growth and yield model. A problem in complex, multi-species forests is that individual tree attributes such as ΔDBH and ΔHT need to be characterized for a large number of distinct woody species of highly varying levels of occurrence. Based on more than 2.5 million ΔDBH observations and over 1 million ΔHT records from up to 60 tree species and genera, respectively, this study aimed to improve existing ΔDBH and ΔHT equations of the Acadian Variant of the Forest Vegetation Simulator (FVS-ACD) using a revised method that utilize tree species as a random effect. Our study clearly highlighted the efficiency and flexibility of this method for predicting ΔDBH and ΔHT. However, results also highlighted shortcomings of this approach, e.g., reversal of plausible parameter signs as a result of combining fixed and random effects parameter estimates after extending the random effect structure by incorporating North American ecoregions. Despite these potential shortcomings, the newly developed ΔDBH and ΔHT equations outperformed the ones currently used in FVS-ACD by reducing prediction bias quantified as mean absolute bias and root mean square error by at least 11% for an independent dataset and up to 41% for the model development dataset. Using the revised ΔDBH and ΔHT estimates, greater prediction accuracy in individual tree aboveground live carbon mass estimation was also found in general but performance varied with dataset and accuracy metric examined. Overall, this analysis highlights the importance and challenges of developing robust ΔDBH and ΔHT equations across broad regions dominated by mixed-species, managed forests.
Forfattere
Peter Annighöfer Martina Mund Dominik Seidel Christian Ammer Aitor Ameztegui Philippe Balandier Ieva Bebre Lluis Coll Catherine Collet Tobias Hamm Franka Huth Heike Schneider Christian Kuehne Magnus Löf Any Mary Petritan Ion Catalin Petritan Peter Schall Jürgen BauhusSammendrag
Just as the aboveground tree organs represent the interface between trees and the atmosphere, roots act as the interface between trees and the soil. In this function, roots take-up water and nutrients, facilitate interactions with soil microflora, anchor trees, and also contribute to the gross primary production of forests. However, in comparison to aboveground plant organs, the biomass of roots is much more difficult to study. In this study, we analyzed 19 European datasets on above- and belowground biomass of juvenile trees of 14 species to identify generalizable estimators of root biomass based on tree sapling dimensions (e.g. height, diameter, aboveground biomass). Such estimations are essential growth and sequestration modelling. In addition, the intention was to study the effect of sapling dimension and light availability on biomass allocation to roots. All aboveground variables were significant predictors for root biomass. But, among aboveground predictors of root biomass plant height performed poorest. When comparing conifer and broadleaf species, the latter tended to have a higher root biomass at a given dimension. Also, with increasing size, the share of belowground biomass tended to increase for the sapling dimensions considered. In most species, there was a trend of increasing relative belowground biomass with increasing light availability. Finally, the height to diameter ratio (H/D) was negatively correlated to relative belowground biomass. This indicates that trees with a high H/D are not only more unstable owing to the unfavorable bending stress resistance, but also because they are comparatively less well anchored in the ground. Thus, single tree stability may be improved through increasing light availability to increase the share of belowground biomass.
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