Nicholas Clarke
Research Professor
Biography
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Questions Observations in permanent forest vegetation plots in Norway and elsewhere indicate that complex changes have taken place over the period 1988–2020. These observations are summarised in the “climate-induced understorey change (CIUC)” hypothesis, i.e. that the understorey vegetation of old-growth boreal forests in Norway undergoes significant long-term changes and that these changes are consistent with the ongoing climate change as an important driver. Seven testable predictions were derived from the CIUC hypothesis. Location Norway. Methods Vegetation has been monitored in a total of 458 permanently marked plots, each 1 m2, in nine old-growth forest sites dominated by Picea abies at intervals of 5–8 years over the 32-year study period. For each of the 52 combinations of site and year, we obtained response variables for the abundance of single species, abundance and species density of taxonomic–ecological species groups and two size classes of cryptogams, and site species richness. All of these variables were subjected to linear regression modelling with site and year as predictors. Results Mean annual temperature, growing-season length and the number of days with precipitation were higher in the study period than in the preceding ca. 30-year period, resulting in increasingly favourable conditions for bryophyte growth. Site species richness decreased by 13% over the 32-year study period. On average, group abundance of vascular plants decreased by 24% (decrease in forbs: 38%). Patterns of group abundance change differed among cryptogam groups: although peat-moss abundance increased by 39%, the abundance of mosses, hepatics and lichens decreased by 13%, 49% and 67%, respectively. Group abundance of small cryptogams decreased by 61%, whereas a 13% increase was found for large cryptogams. Of 61 single species tested for abundance change, a significant decrease was found for 43 species, whereas a significant increase was found only for 6 species. Conclusions The major patterns of change in species richness, group species density and group abundance observed over the 32-year study period accord with most predictions from the CIUC hypothesis and are interpreted as direct and indirect responses to climate change, partly mediated through changes in the population dynamics of microtine rodents. The more favourable climate for bryophyte growth explains the observed increase for a few large bryophyte species, whereas the decrease observed for small mosses and hepatics is interpreted as an indirect amensalistic effect, brought about by shading and burial in mats of larger species and accelerated by reduced fine-scale disturbance by microtine rodents. Indirect effects of a thicker moss mat most likely drive the vascular plant decline although long-term effects of tree-stand dynamics and former logging cannot be completely ruled out. Our results suggest that the ongoing climate change has extensive, cascading effects on boreal forest ecosystems. The importance of long time-series of permanent vegetation plots for detecting and understanding the effects of climate change on boreal forests is emphasised.
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Arne Verstraeten Nicolas Bruffaerts Fabiana Cristofolini Elena Vanguelova Johan Neirynck Gerrit Genouw Bruno de Vos Peter Waldner Anne Thimonier Anita Nussbaumer Mathias Neumann Sue Benham Pasi Rautio Liisa Ukonmaanaho Päivi Merilä Antti-Jussi Lindroos Annika Saarto Jukka Reiniharju Nicholas Clarke Volkmar Timmermann Manuel Nicolas Maria Schmitt Katrin Meusburger Anna Kowalska Idalia Kasprzyk Katarzyna Kluska Łukasz Grewling Małgorzata Malkiewicz Lars Vesterdal Morten Ingerslev Miklós Manninger Donat Magyar Hugues Titeux Gunilla Pihl Karlsson Regula Gehrig Sandy Adriaenssens Agneta Ekebom Åslög Dahl Marco Ferretti Elena GottardiniAbstract
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Arne Verstraeten Peter Waldner Aldo Marchetto Andreas Schmitz Nicholas Clarke Anne Thimonier Catherine Hilgers Anne-Katrin Prescher Karin HansenAbstract
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Nicholas ClarkeAbstract
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Shu Zhang Lingbo Meng Jian Hou Xiaodan Liu Abiola O. Ogundeji Zeyu Cheng Tengjiao Yin Nicholas Clarke Baozhong Hu Shumin LiAbstract
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In a fertiliser experiment in a Norway spruce forest in SE Norway, four treatments were applied in a block design with three replicates per treatment. Treatments included 3 t wood ash ha−1 (Ash), 150 kg nitrogen ha−1 (N), wood ash and nitrogen combined (Ash + N), and unfertilised control (Ctrl). Treatment effects on understory plant species numbers, single abundances of species and (summarised) cover of main species groups were studied. Two years after treatment there were no significant changes for species numbers or abundances of woody species, dwarf shrubs or pteridophytes, nor for Sphagnum spp. in the bottom layer. The cover of graminoids decreased in Ctrl plots. Herb cover increased significantly in Ash + N and N plots due to the increase of Melampyrum sylvaticum. In Ash + N plots, mosses decreased significantly in species number, while their cover increased. Moss cover also decreased significantly in N plots. The species number and cover of hepatics decreased significantly in Ash and Ash + N plots. Hepatics cover also decreased in Ctrl plots. Both the lichen number and cover decreased in Ash + N plots. Single species abundances decreased for many bryophytes in fertilised plots. To conclude, fertilisation had modest effects on vascular plants, while bryophytes were more strongly affected, especially by Ash + N.
Authors
Daniel Liptzin Jens Boy John L. Campbell Nicholas Clarke Jean-Paul Laclau Roberto Godoy Sherri L. Johnson Klaus Kaiser Gene E. Likens Gunilla Pihl Karlsson Daniel Markewitz Michela Rogora Stephen D. Sebestyen James B. Shanley Elena Vanguelova Arne Verstraeten Wolfgang Wilcke Fred Worrall William H. McDowellAbstract
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Martin Forsius Maximilian Posch Maria Holmberg Jussi Vuorenmaa Sirpa Kleemola Algirdas Augustaitis Burkhard Beudert Witold Bochenek Nicholas Clarke Heleen de Wit Thomas Dirnböck Jane Frey Ulf Grandin Hannele Hakola Johannes Kobler Pavel Krám Antti-Jussi Lindroos Stefan Löfgren Tomasz Pecka Pernilla Rönnback Krzysztof Skotak Józef Szpikowski Liisa Ukonmaanaho Salar Valinia Milan VáňaAbstract
Anthropogenic emissions of nitrogen (N) and sulphur (S) compounds and their long-range transport have caused widespread negative impacts on different ecosystems. Critical loads (CLs) are deposition thresholds used to describe the sensitivity of ecosystems to atmospheric deposition. The CL methodology has been a key science-based tool for assessing the environmental consequences of air pollution. We computed CLs for eutrophication and acidification using a European long-term dataset of intensively studied forested ecosystem sites (n = 17) in northern and central Europe. The sites belong to the ICP IM and eLTER networks. The link between the site-specific calculations and time-series of CL exceedances and measured site data was evaluated using long-term measurements (1990–2017) for bulk deposition, throughfall and runoff water chemistry. Novel techniques for presenting exceedances of CLs and their temporal development were also developed. Concentrations and fluxes of sulphate, total inorganic nitrogen (TIN) and acidity in deposition substantially decreased at the sites. Decreases in S deposition resulted in statistically significant decreased concentrations and fluxes of sulphate in runoff and decreasing trends of TIN in runoff were more common than increasing trends. The temporal developments of the exceedance of the CLs indicated the more effective reductions of S deposition compared to N at the sites. There was a relation between calculated exceedance of the CLs and measured runoff water concentrations and fluxes, and most sites with higher CL exceedances showed larger decreases in both TIN and H+ concentrations and fluxes. Sites with higher cumulative exceedance of eutrophication CLs (averaged over 3 and 30 years) generally showed higher TIN concentrations in runoff. The results provided evidence on the link between CL exceedances and empirical impacts, increasing confidence in the methodology used for the European-scale CL calculations. The results also confirm that emission abatement actions are having their intended effects on CL exceedances and ecosystem impacts.
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Nicholas ClarkeAbstract
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Nicholas Clarke Lars Pødenphant Kiær O. Janne Kjønaas Teresa Gómez de la Bárcena Lars Vesterdal Inge Stupak Leena Finér Staffan Jacobson Kestutis Armolaitis Dagnija Lazdina Helena Marta Stefánsdóttir Bjarni D. SigurdssonAbstract
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Nicholas Clarke Lars Pødenphant Kiær O. Janne Kjønaas Teresa Gómez de la Bárcena Lars Vesterdal Inge Stupak Leena Finér Staffan Jacobson Kestutis Armolaitis Dagnija Lazdina Helena Marta Stefánsdóttir Bjarni D. SigurdssonAbstract
The use of biomass from forest harvesting residues or stumps for bioenergy has been increasing in the northern European region in the last decade. The present analysis is a regional review from Nordic and UK coniferous forests, focusing on the effects of whole-tree harvesting (WTH) or whole-tree thinning (WTT) and of WTH followed by stump removal (WTH + S) on the forest floor and mineral soil, and includes a wider array of chemistry data than other existing meta-analyses. All intensified treaments led to significant decreases of soil organic carbon (SOC) stock and total N stock in the forest floor (FF), but relative responses compared with stem-only harvesting were less consistent in the topsoil (TS) and no effects were detected in the subsoil (SS). Exchangeable P was reduced in the FF and TS both after WTT and WTH, but significant changes in exchangeable Ca, K, Mg and Zn depended on soil layer and treatment. WTH significantly lowered pH and base saturation (BS) in the FF, but without apparent changes in cation exchange capacity (CEC). The only significant WTH-effects in the SS were reductions in CEC and BS. Spruce- and pine-dominated stands had comparable negative relative responses in the FF for most elements measured except Mg and for pH. Relative responses to intensified harvesting scaled positively with growing season temperature and precipitation for most variables, most strongly in FF, less in the TS, but almost never in the SS, but were negative for P and Al. The greater reduction in FF and TS for soil organic carbon after intensive harvesting decreased with time and meta-regression models predicted an average duration of 20–30 years, while many other chemical parameters generally showed linear effects for 30–45 years after intensified harvesting. Exchangeable acidity (EA), BS and pH all showed the reversed effect with time, i.e. an initial increase and then gradual decrease over 24–45 years. The subsoil never showed a significant temporal effect. Our results generally support greater reductions in nutrient concentrations, SOC and total N in forest soil after WTH compared with SOH in northern temperate and boreal forest ecosystems.
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Arne Verstraeten Elena Gottardini Nicolas Bruffaerts Fabiana Cristofolini Elena Vanguelova Johan Neirynck Gerrit Genouw Bruno de Vos Peter Waldner Anne Thimonier Anita Nussbaumer Mathias Neumann Sue Benham Pasi Rautio Liisa Ukonmaanaho Päivi Merilä Annika Saarto Jukka Reiniharju Peter Roskams Geert Sioen Nathalie Cools Nicholas Clarke Volkmar Timmermann Hans-Peter Dietrich Manuel Nicolas Maria Schmitt Katrin Meusburger Silvio Schüler Anna Kowalska Idalia Kasprzyk Katarzyna Kluska Łukasz Grewling Joanna Święta-Musznicka Małgorzata Latałowa Marcelina Zimny Małgorzata Malkiewicz Lars Vesterdal Miklós Manninger Donat Magyar Hugues Titeux Gunilla Pihl-Karlsson Marco FerrettiAbstract
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Background Bioenergy plays a key role in the transition to a sustainable economy in Europe, but its own sustainability is being questioned. We study the experiences of Sweden, Finland, Denmark and Norway, to find out whether the forest-based bioenergy chains developed in the four countries have led to unsustainable outcomes and how the countries manage the sustainability risks. Data were collected from a diversity of sources including interviews, statistical databases, the scientific literature, government planning documents and legislation. Results Sustainability risks of deforestation, degradation of forests, reduced carbon pools in forests, expensive biopower and heat, resource competition, and lack of acceptance at the local level are considered. The experience of the four countries shows that the sustainability risks can to a high degree be managed with voluntary measures without resorting to prescriptive measures. It is possible to add to the carbon pools of forests along with higher harvest volumes if the risks are well managed. There is, however, a marginal trade-off between harvest volume and carbon pools. Economic sustainability risks may be more challenging than ecological risks because the competitiveness order of renewable energy technologies has been reversed in the last decade. The risk of resource competition harming other sectors in the economy was found to be small and manageable but requires continuous monitoring. Local communities acting as bioenergy communities have been agents of change behind the most expansive bioenergy chains. A fear of non-local actors reaping the economic gains involved in bioenergy chains was found to be one of the risks to the trust and acceptance necessary for local communities to act as bioenergy communities. Conclusions The Nordic experience shows that it has been possible to manage the sustainability risks examined in this paper to an extent avoiding unsustainable outcomes. Sustainability risks have been managed by developing an institutional framework involving laws, regulations, standards and community commitments. Particularly on the local level, bioenergy chains should be developed with stakeholder involvement in development and use, in order to safeguard the legitimacy of bioenergy development and reconcile tensions between the global quest for a climate neutral economy and the local quest for an economically viable community. Keywords: Bioenergy, Sustainability, Risk assessment, Risk management, Nordic countries
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Brian D. Titus Kevin Brown Heljä-Sisko Helmisaari Elena Vanguelova Inge Stupak Alexander Evans Nicholas Clarke Claudia Guidi Viktor J. Bruckman Iveta Varnagiryte-Kabasinskiene Kestutis Armolaitis Wim de Vries Keizo Hirai Lilli Kaarakka Karen Hogg Pam ReeceAbstract
Forest biomass harvesting guidelines help ensure the ecological sustainability of forest residue harvesting for bioenergy and bioproducts, and hence contribute to social license for a growing bioeconomy. Guidelines, typically voluntary, provide a means to achieve outcomes often required by legislation, and must address needs related to local or regional context, jurisdictional compatibility with regulations, issues of temporal and spatial scale, and incorporation of appropriate scientific information. Given this complexity, comprehensive reviews of existing guidelines can aid in development of new guidelines or revision of existing ones. We reviewed 32 guidelines covering 43 jurisdictions in the USA, Canada, Europe and East Asia to expand upon information evaluated and recommendations provided in previous guideline reviews, and compiled a searchable spreadsheet of direct quotations from documents as a foundation for our review. Guidelines were considered in the context of sustainable forest management (SFM), focusing on guideline scope and objectives, environmental sustainability concerns (soils, site productivity, biodiversity, water and carbon) and social concerns (visual aesthetics, recreation, and preservation of cultural, historical and archaeological sites). We discuss the role of guidelines within the context of other governance mechanisms such as SFM policies, trade regulations and non-state market-driven (NSMD) standards, including certification systems. The review provides a comprehensive resource for those developing guidelines, or defining sustainability standards for market access or compliance with public regulations, and/or concerned about the sustainability of forest biomass harvesting. We recommend that those developing or updating guidelines consider (i) the importance of well-defined and understood terminology, consistent where possible with guidelines in other jurisdictions or regions; (ii) guidance based on locally relevant research, and periodically updated to incorporate current knowledge and operational experience; (iii) use of indicators of sensitive soils, sites, and stands which are relevant to ecological processes and can be applied operationally; and (iv) incorporation of climate impacts, long-term soil carbon storage, and general carbon balance considerations when defining sustainable forest biomass availability. Successful implementation of guidelines depends both on the relevance of the information and on the process used to develop and communicate it; hence, appropriate stakeholders should be involved early in guideline development.
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Frode Sundnes Marianne Karlsson Froukje Maria Platjouw Nicholas Clarke Øyvind Kaste Salar ValiniaAbstract
While the role of forestry in mitigating climate change is increasingly subject to political commitment, other areas, such as water protection, may be at risk. In this study, we ask whether surface waters are sufficiently safeguarded in relation to the 2015 launch of a series of measures to intensify forest management for mitigation of climate change in Norway. First, we assess how impacts on water are accounted for in existing regulations for sustainable forestry. Secondly, we provide an overview of the impacts of forestry on water quality relevant to three support schemes: afforestation on new areas, increased stocking density in existing forests, and forest fertilisation. Lastly, we assess the uncertainties that exist with regard to surface waters in the implementation of these measures. We find that the safeguards in place are adequate to protect water resources at the point of initiation, but there is a large degree of uncertainty as to the long-term effect of these mitigation measures.
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Denne rapporten er en litteratursammenstilling over tap av suspendert stoff, fosfor og nitrogen fra arealer med hhv. jordbruk og skog/utmark. I tillegg er det gjort en vurdering av tilsvarende tap i perioden der nydyrking gjennomføres. I de norske studiene som er gjennomgått er gjennomsnittlige tap av nitrogen 17 ganger høyere fra jordbruk enn fra skog. Tilsvarende er fosfortap 56 ganger høyere og tap av suspendert stoff 106 ganger høyere fra jordbruk enn fra skog.
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Jiangsan Zhao Dmitry Kechasov Boris Rewald Gernot Bodner Michel Verheul Nicholas Clarke Jihong Liu ClarkeAbstract
Hyperspectral imaging has many applications. However, the high device costs and low hyperspectral image resolution are major obstacles limiting its wider application in agriculture and other fields. Hyperspectral image reconstruction from a single RGB image fully addresses these two problems. The robust HSCNN-R model with mean relative absolute error loss function and evaluated by the Mean Relative Absolute Error metric was selected through permutation tests from models with combinations of loss functions and evaluation metrics, using tomato as a case study. Hyperspectral images were subsequently reconstructed from single tomato RGB images taken by a smartphone camera. The reconstructed images were used to predict tomato quality properties such as the ratio of soluble solid content to total titratable acidity and normalized anthocyanin index. Both predicted parameters showed very good agreement with corresponding “ground truth” values and high significance in an F test. This study showed the suitability of hyperspectral image reconstruction from single RGB images for fruit quality control purposes, underpinning the potential of the technology—recovering hyperspectral properties in high resolution—for real-world, real time monitoring applications in agriculture any beyond.
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Inge Stupak Tat Smith Nicholas Clarke Teodorita Al-Seadi Lina Beniušienė Niclas Scott Bentsen Quentin Cheung Virginia Dale Jinke van Dam Rocio Diaz-Chavez Uwe Fritsche Martyn Futter Jianbang Gan Kaija Hakala Thomas Horschig Martin Junginger Yoko Kitigawa Brian Kittler Keith Kline Charles Lalonde Søren Larsen Dagnija Lazdina Thuy P. T. Mai-Moulin Maha Mansoor Edmund Mupondwa Shyam Nair Nathaniel Newlands Liviu Nichiforel Marjo Palviainen John Stanturf Kay Schaubach Johanny Arilexis Perez Sierra Vita Tilvikiene Brian Titus Daniela Thrän Sergio Ugarte Liisa Ukonmaanaho Iveta Varnagiryte-Kabasinskiene Maria WellischAbstract
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Humic substances are important indicators of soil fertility. The fluorescence properties of humic acids from black soils in Harbin, northeast China, were investigated, after long-term fertilization using treatments with or without mineral fertilizer (NPK) and organic manure. Excitation and emission matrices combined with parallel factor analysis were used to investigate the structure of the humic acid. Principal component analysis was performed to select the most suitable parameters for the description of humic acid. The dimension reduction for the original fluorescence parameters extracted two principal components. By using the two principal component scores as a new index for clustering, it was concluded that long-term fertilization treatments in black soil in Harbin clustered into three groups of manure + NPK and organic manure treatments, NPK treatment, and soil without any fertilization. Manure + NPK fertilization and manure fertilization alone led to a higher degree of humification than NPK only or the control. We conclude that long-term fertilization with organic matter with or without NPK could increase the humification degree of these soils.
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Jyrki Jauhiainen Jukka Alm Brynhildur Bjarnadottir Ingeborg Callesen Jesper R Christiansen Nicholas Clarke Lise Dalsgaard Hongxing He Sabine Jordan Vaiva Kazanavičiūtė Leif Klemedtsson Ari Laurén Andis Lazdiņš Aleksi Lehtonen Annalea Lohila Ainars Lupikis Ülo Mander Kari Minkkinen Åsa Kasimir Mats Olsson Paavo Ojanen Hlynur Óskarsson Bjarni D. Sigurdsson Gunnhild Søgaard Kaido Soosaar Lars Vesterdal Raija LaihoAbstract
Drained organic forest soils in boreal and temperate climate zones are believed to be significant sources of the greenhouse gases (GHGs) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), but the annual fluxes are still highly uncertain. Drained organic soils exemplify systems where many studies are still carried out with relatively small resources, several methodologies and manually operated systems, which further involve different options for the detailed design of the measurement and data analysis protocols for deriving the annual flux. It would be beneficial to set certain guidelines for how to measure and report the data, so that data from individual studies could also be used in synthesis work based on data collation and modelling. Such synthesis work is necessary for deciphering general patterns and trends related to, e.g., site types, climate, and management, and the development of corresponding emission factors, i.e. estimates of the net annual soil GHG emission and removal, which can be used in GHG inventories. Development of specific emission factors also sets prerequisites for the background or environmental data to be reported in individual studies. We argue that wide applicability greatly increases the value of individual studies. An overall objective of this paper is to support future monitoring campaigns in obtaining high-value data. We analysed peer-reviewed publications presenting CO2, CH4 and N2O flux data for drained organic forest soils in boreal and temperate climate zones, focusing on data that have been used, or have the potential to be used, for estimating net annual soil GHG emissions and removals. We evaluated the methods used in data collection and identified major gaps in background or environmental data. Based on these, we formulated recommendations for future research.
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Arne Verstraeten Elena Gottardini Nicolas Bruffaerts Bruno De Vos Elena Vanguelova Fabiana Cristofolini Sue Benham Pasi Rautio Liisa Ukonmaanaho Päivi Merilä Annika Saarto Peter Waldner Marijke Hendrickx Gerrit Genouw Peter Roskams Nathalie Cools Johan Neirynck Anita Nussbaumer Mathias Neumann Nicholas Clarke Volkmar Timmermann Karin Hansen Hans-Peter Dietrich Manuel Nicolas Maria Schmitt Anne Thimonier Katrin Meusburger Silvio Schüler Anna KowalskaAbstract
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The objective of this study was to make an overview assessment of the potential effects of intensified forest management, promoted by the Norwegian government as a climate mitigation measure, on water quality in Norwegian surface waters. This study evaluated the following measures for forest intensification: (i) afforestation, (ii) intensification of planting and (iii) nitrogen fertilization shortly before harvest. A substantial literature review was made and a further development of the DWARF- framework tailored for Norwegian conditions provided the base for the study. The assessments were made based on the potential effects after forest harvest, using different management strategies like stem-only harvest and whole-three harvest. The potential effects were analysed on multiple parameters with focus on acidification, eutrophication, heavy metals, and carbon sequestration. The study used temporal resolution to address what effects the forest management practices might lead to 1, 10 and 100 years after harvest. This study concludes that there will be trade-offs between transitioning to a low carbon society and water quality, and the severity of effects may differ if they are evaluated on an annual, decadal or century scale.
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Arne Verstraeten Elena Gottardini Nicolas Bruffaerts Bruno De Vos Elena Vanguelova Fabiana Cristofolini Gerrit Genouw Anita Nussbaumer Mathias Neumann Sue Benham Pasi Rautio Liisa Ukonmaanaho Päivi Merilä Annika Saarto Jukka Reiniharju Peter Waldner Marijke Hendrickx Peter Roskams Nathalie Cools Johan Neirynck Arthur De Haeck Yvan De Bodt Geert Sioen Nicholas Clarke Volkmar Timmermann Karin Hansen Hans-Peter Dietrich Manuel Nicolas Maria Schmitt Anne Thimonier Katrin Meusburger Silvio Schüler Anna Kowalska Idalia Kasprzyk Katarzyna Borycka Łukasz Grewling Joanna Święta-Musznicka Małgorzata Latałowa Marcelina Zimny Małgorzata Malkiewicz Lars Vesterdal Iben Margrete Thomsen Miklós Manninger Donat Magyar Gergely Mányoki Hugues TiteuxAbstract
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Inge Stupak Tat Smith Nicholas Clarke Teodorita Al-Seadi Lina Beniušienė Niclas Scott Bentsen Quentin Cheung Virginia Dale Jinke van Dam Rocio Diaz-Chavez Uwe Fritsche Martyn Futter Jianbang Gan Kaija Hakala Thomas Horschig Martin Junginger Yoko Kitigawa Brian Kittler Keith Kline Charles Lalonde Søren Larsen Dagnija Lazdina Thuy P. T. Mai-Moulin Maha Mansoor Edmund Mupondwa Shyam Nair Nathaniel Newlands Liviu Nichiforel Marjo Palviainen John Stanturf Kay Schaubach Johanny Arilexis Perez Sierra Vita Tilvikiene Brian Titus Daniela Thrän Sergio Ugarte Liisa Ukonmaanaho Iveta Varnagyrite-Kabasinkiene Maria WellischAbstract
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Nicholas ClarkeAbstract
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Arne Verstraeten Elena Gottardini Elena Vanguelova Peter Waldner Nicolas Bruffaerts Anita Nussbaumer Mathias Neumann Nicholas Clarke Karin Hansen Pasi Rautio Liisa UkonmaanahoAbstract
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Frode Sundnes Marianne Karlsson Froukje Maria Platjouw Salar Valinia Nicholas Clarke Øyvind KasteAbstract
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Nicholas ClarkeAbstract
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Inge Stupak Tat Smith Nicholas Clarke Niclas Scott Bentsen Virginia Dale Jinke van Dam Rocio Diaz-Chavez Ulrike Eppler Uwe Fritsche Martyn Futter Jianbang Gan Kaija Hakala Thomas Horschig Martin Junginger Keith Kline Søren Larsen Charles Lalonde Maha Mansoor Thuy P.T. Mai-Moulin Shyam Nair Liviu Nichiforel Marjo Palviainen John Stanturf Kay Schaubach Vita Tilvikiene Brian Titus Daniela Thrän Liisa Ukonmaanaho Maria WellischAbstract
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Brian Titus Kendrick Brown Inge Stupak Helja-Sisko Helmisaari Viktor Bruckman Alexander Evans Elena Vanguelova Nicholas Clarke Iveta Varnagiryte-Kabasinskiene Kestutis ArmolaitisAbstract
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Jussi Vuorenmaa Algirdas Augustaitis Burkhard Beudert Witold Bochenek Nicholas Clarke Heleen A de Wit Thomas Dirnböck Jane Frey Hannele Hakola Sirpa Kleemola Johannes Kobler Pavel Krám Antti-Jussi Lindroos Lars Lundin Stefan Löfgren Aldo Marchetto Tomasz Pecka Hubert Schulte-Bisping Krzysztof Skotak Anatoly Srybny Józef Szpikowski Liisa Ukonmaanaho Milan Váňa Staffan Åkerblom Martin ForsiusAbstract
The international Long-Term Ecological Research Network (ILTER) encompasses hundreds of long-term research/monitoring sites located in a wide array of ecosystems that can help us understand environmental change across the globe. We evaluated long-term trends (1990–2015) for bulk deposition, throughfall and runoff water chemistry and fluxes, and climatic variables in 25 forested catchments in Europe belonging to the UNECE International Cooperative Programme on Integrated Monitoring of Air Pollution Effects on Ecosystems (ICP IM). Many of the IM sites form part of the monitoring infrastructures of this larger ILTER network. Trends were evaluated for monthly concentrations of non-marine (anthropogenic fraction, denoted as x) sulphate (xSO4) and base cations x(Ca + Mg), hydrogen ion (H+), inorganic N (NO3 and NH4) and ANC (Acid Neutralising Capacity) and their respective fluxes into and out of the catchments and for monthly precipitation, runoff and air temperature. A significant decrease of xSO4 deposition resulted in decreases in concentrations and fluxes of xSO4 in runoff, being significant at 90% and 60% of the sites, respectively. Bulk deposition of NO3 and NH4 decreased significantly at 60–80% (concentrations) and 40–60% (fluxes) of the sites. Concentrations and fluxes of NO3 in runoff decreased at 73% and 63% of the sites, respectively, and NO3 concentrations decreased significantly at 50% of the sites. Thus, the LTER/ICP IM network confirms the positive effects of the emission reductions in Europe. Air temperature increased significantly at 61% of the sites, while trends for precipitation and runoff were rarely significant. The site-specific variation of xSO4 concentrations in runoff was most strongly explained by deposition. Climatic variables and deposition explained the variation of inorganic N concentrations in runoff at single sites poorly, and as yet there are no clear signs of a consistent deposition-driven or climate-driven increase in inorganic N exports in the catchments.
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A large proportion of global agricultural soils contain suboptimal available phosphorus (P) for the growth of many plant species. Boron (B) plays important roles in plant growth and development, but limited research has been conducted to study B uptake under low P availability. This study comprised a hydroponic and a mini-rhizobox experiment with canola (Brassica napus L.), potato (Solanum tuberosum L.) and wheat (Triticum aestivum L.) under P sufficient and deficient conditions. Boron concentrations, rhizosphere soil pH, and gene expression of BnBOR1 in canola were determined. Shoot B concentrations were found significantly increased (11–149%) by low P availability in potato and canola but not in wheat. Reverse transcription polymerase chain reaction (RT-PCR) indicated that BnBOR1;2a, BnBOR1;2c, and BnBOR1;3c were up-regulated after seven days of low P treatment in canola roots. Our results indicate that plant shoot B concentration was dramatically influenced by P availability, and dicots and monocots showed a contrasting B concentration response to low P availability.
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Ingeborg Callesen Nicholas Clarke Andis Lazdinš Iveta Varnagiryte-Kabasinskiene Karsten Raulund-RasmussenAbstract
The long-term carrying capacity for biomass production is highly dependent on available soil resources. A soil test method for potential nutrient release capability was applied to 23 Nordic and Baltic forest soil profiles. The soils had coarse (10), medium (12) and fine (1) soil texture and most were podsolising. Extraction with dilute (0.1 M, 1:50 sample:solution ratio) nitric acid for 2 h was followed by 48 h and 168 h of extraction in soil samples from pedogenetic horizons. Dilute nitric acid solution was replaced after each step and release of mineral nutrient elements in solution was determined. C-horizon nutrient release (µmol g−1 fine earth, 0–218 h) was negatively correlated with mean annual temperature (MAT 0.5–8.5 °C) and for potassium (K) also mean annual precipitation (MAP 523–1440 mm y−1) suggesting a gradient in the mineralogy of the parent material that sediment transports during Pleistocene glaciations have not distorted. In B-horizons of sandy parent materials with felsic mineralogy cumulative nutrient release was positively correlated with pH and with Al and Fe release suggesting accumulation and stabilisation of nutrients in pedogenic products. E-horizons had less nutrient release capability than C-horizons, indicating a more weathered state of E-horizon parent material. Soil formation due to mineral dissolution and leaching of base cations and the gradient in parent material origin and weathering state both affected the observed pattern of nutrient release. On soils with very low mineral P resources (e.g. < 250 kg P ha−1 to 50 cm) by repeated dilute acid extraction, harvest of nutrient rich biomass will not be sustainable. However, it can’t be concluded that sites with high P availability by 0.1 M HNO3 can support an intensive harvest without compensation of P (and Ca) by fertilisation. Due to buffering of removed base cations in B-horizons, nutrient export with biomass may not be traceable as pH decline at decadal time scale. Therefore, the direct measurement of nutrient stocks by the extraction procedure (or other similar assessment of nutrient reserves by strong acid) is suggested as indicative for the mineral weathering capability of forest soils to recover from P and base cation depletion by biomass harvest.
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Tonje Ingeborg Økland Jørn-Frode Nordbakken Holger Lange Ingvald Røsberg Kjersti Holt Hanssen Nicholas ClarkeAbstract
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James Johnson Elisabeth Graf Pannatier Stefano Carnicelli Guia Cecchini Nicholas Clarke Nathalie Cools Karin Hansen Henning Meesenburg Tiina M. Nieminen Gunilla Pihl-Karlsson Hugues Titeux Elena Vanguelova Arne Verstraeten Lars Vesterdal Peter Waldner Mathieu JonardAbstract
Acid deposition arising from sulphur (S) and nitrogen (N) emissions from fossil fuel combustion and agriculture has contributed to the acidification of terrestrial ecosys- tems in many regions globally. However, in Europe and North America, S deposition has greatly decreased in recent decades due to emissions controls. In this study, we assessed the response of soil solution chemistry in mineral horizons of European forests to these changes. Trends in pH, acid neutralizing capacity (ANC), major ions, total aluminium (Al tot ) and dissolved organic carbon were determined for the period 1995–2012. Plots with at least 10 years of observations from the ICP Forests moni- toring network were used. Trends were assessed for the upper mineral soil (10– 20 cm, 104 plots) and subsoil (40–80 cm, 162 plots). There was a large decrease in the concentration of sulphate (SO 2 4 ) in soil solution; over a 10-year period (2000– 2010), SO 2 4 decreased by 52% at 10–20 cm and 40% at 40–80 cm. Nitrate was unchanged at 10–20 cm but decreased at 40–80 cm. The decrease in acid anions was accompanied by a large and significant decrease in the concentration of the nutrient base cations: calcium, magnesium and potassium (Bc = Ca 2+ + Mg 2+ + K + ) and Al tot over the entire dataset. The response of soil solution acidity was nonuni- form. At 10–20 cm, ANC increased in acid-sensitive soils (base saturation ≤10%) indicating a recovery, but ANC decreased in soils with base saturation >10%. At 40–80 cm, ANC remained unchanged in acid-sensitive soils (base saturation ≤20%, pH CaCl 2 ≤ 4.5) and decreased in better-buffered soils (base saturation >20%, pH CaCl 2 > 4.5). In addition, the molar ratio of Bc to Al tot either did not change or decreased. The results suggest a long-time lag between emission abatement and changes in soil solution acidity and underline the importance of long-term monitor- ing in evaluating ecosystem response to decreases in deposition.
Authors
Arne Verstraeten Elena Gottardini Nicolas Bruffaerts Bruno de Vos Elena Vanguelova Fabiana Cristofolini Sue Benham Pasi Rautio Liisa Ukonmaanaho Päivi Merilä Peter Waldner Marijke Hendrickx Gerrit Genouw Peter Roskams Nathalie Cools J Neirynck Anita Nussbaumer Mathias Neumann Nicholas Clarke Volkmar Timmermann Karin Hansen Hans-Peter Diettrich Manuel Nicolas Maria Schmitt Anne Thimonier Katrin Meusburger Silvio Schueler Anna KowalskaAbstract
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Authors
Nicholas ClarkeAbstract
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Authors
Nicholas ClarkeAbstract
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Authors
Nicholas Clarke Silje Skår O. Janne Kjønaas Kjersti Holt Hanssen Tonje Ingeborg Økland Jørn-Frode Nordbakken Toril Drabløs Eldhuset Holger LangeAbstract
Short-term (three to four years) effects of forest harvesting on soil solution chemistry were investigated at two Norway spruce sites in southern Norway, differing in precipitation amount and topography. Experimental plots were either harvested conventionally (stem-only harvesting, SOH) or whole trees, including crowns, twigs and branches were removed (whole-tree harvesting, WTH), leaving residue piles on the ground for some months before removal. The WTH treatment had two sub-treatments: WTH-pile where there had been piles and WTH-removal, from where residues had been removed to make piles. Increased soil solution concentrations of NO3–N, total N, Ca, Mg and K at 30 cm depth, shown by peaks in concentrations in the years after harvesting, were found at the drier, less steep site in eastern Norway after SOH and WTH-pile, but less so after WTH-removal. At the wetter, steeper site in western Norway, peaks were often observed also at WTH-removal plots, which might reflect within-site differences in water pathways due largely to site topography.
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Authors
Nicholas ClarkeAbstract
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Authors
Nicholas ClarkeAbstract
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Authors
Jyrki Jauhiainen Jukka Alm Brynhildur Bjarnadottir Ingeborg Callesen Jesper R Christiansen Nicholas Clarke Lise Dalsgaard Hongxing He Sabine Jordan Åsa Kasimir Vaiva Kazanaviciute Leif Klemedtsson Ari Laurén Andis Lazdins Aleksi Lehtonen Annalea Lohila Ainars Lupikis Ülo Mander Kari Minkkinen Paavo Ojanen Mats Olsson Hlynur Óskarsson Bjarni D. Sigurdsson Kaido Soosaar Gunnhild Søgaard Lars Vesterdal Raija LaihoAbstract
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Abstract
Phosphorus (P) is one of the main limiting factors for crop productivity while rhizosphere organic anions have been hypothesized to play an important role in P acquisition. Sampling in a long-term field experiment was carried out in order to understand the impact of long-term differences in P fertilization on secretion of organic anions under field conditions. Rhizosphere organic anions were extracted and analyzed every week from three leaves stage to completed flowering stage of wheat (Triticum aestivum) grown on plots that have received 0 (P0) or 48 (P48) kg P ha−1 year−1 since 1966. The study showed that it is possible to extract and quantify rhizosphere organic anions from field plots. In P48 plots, root P concentrations decreased around 40 % at the early stages (before heading), compared with the first sampling, and then increased slightly, while plants grown in P0 plots showed the opposite trend. Malate was the main organic anion secreted throughout all the wheat growth stages. Rhizosphere citrate and malate showed negative and positive correlations (P < 0.05) respectively with root P concentrations at 29 and 42 days after emergence (DAE). Rhizosphere organic anion concentrations were quite low until 29 DAE and then increased up to 4–10-fold until 42 DAE; these concentrations declined at later stages, indicating that root-released organic anions may have been affected by developmental stage and root P concentration. The present study provides valuable information about the relationship between rhizosphere organic anions and various P concentrations of wheat grown in the field.
Authors
Andreas Schmitz Karin Hansen Alexa Michel Anne-Katrin Prescher Tanja GM Sanders Walter Seidling Nicholas Clarke Arne Verstraeten Gunilla Pihl Karlsson Daniel Žlindra Lars Vesterdal Sue Benham David Elustondo Manuel Nicolas Peter Waldner Carmen IacobanAbstract
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Authors
Jussi Vuorenmaa Algirdas Augustaitis Burkhard Beudert Nicholas Clarke Heleen de Wit Thomas Dirnböck Jane Frey Martin Forsius Iveta Indriksone Sirpa Kleemola Johannes Kobler Pavel Kram Antti-Jussi Lindroos Lars Lundin Tuija Ruoho-Airola Liisa Ukonmaanaho Milan VánaAbstract
Empirical evidence based on integrated environmental monitoring including physical, chemical and biological variables is essential for evaluating the ecosystem benefits of costly emission reduction policies. The international multidisciplinary ICP IM (International Cooperative Programme on Integrated Monitoring of Air Pollution Effects on Ecosystems) programme studies the integrated effects of air pollution and climate change on ecosystems in unmanaged and calibrated forested catchments. We calculated site-specific annual input-output budgets for sulphate (SO4) and total inorganic nitrogen (TIN NO3- N + NH4-N) for 17 European ICP IM sites in 1990–2012. Temporal trends for input (deposition) and output (runoff water) fluxes and the net retention/net release of SO4 and TIN were also analysed. Large differences in the input and output fluxes of SO4 and TIN reflect important gradients of air pollution effects in Europe, with the highest deposition and runoff water fluxes at IM sites located in southern Scandinavia and in parts of Central and Eastern Europe and the lowest fluxes at more remote sites in northern European regions. A significant decrease in the total (wet + dry) deposition of non-marine SO4 and bulk deposition of TIN was found at 90% and 65% of the sites, respectively. Output fluxes of non-marine SO4 in runoff decreased significantly at 65% of the sites, indicating positive effects of the international emission abatement actions in Europe during the last 20 years. Catchments retained SO4 in the early and mid1990s, but this shifted towards a net release in the late 1990s, which may be due to the mobilization of legacy S pools accumulated during times of high atmospheric SO4 deposition. Despite decreased deposition, TIN output fluxes and retention rates showed a mixed response with both decreasing (9 sites) and increasing (8 sites) trend slopes, and trends were rarely significant. In general, TIN was strongly retained in the catchments not affected by natural disturbances. The long-term annual variation in net releases for SO4 was explained by variations in runoff and SO4 concentrations in deposition, while a variation in TIN concentrations in runoff was mostly associated with a variation of the TIN retention rate in catchments. The net release of SO4 from forest soils may delay the recovery from acidification for surface waters and the continued enrichment of nitrogen in catchment soils poses a threat to terrestrial biodiversity and may ultimately lead to a higher TIN runoff through N-saturation. Continued monitoring and further evaluations of mass balance budgets are thus needed.
Abstract
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Authors
Nicholas Clarke Tonje Ingeborg Økland Kjersti Holt Hanssen Jørn-Frode Nordbakken Katarzyna WasakAbstract
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Abstract
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Authors
Inge Stupak Vivian Kvist-Johannsen Thomas Nord-Larsen Lars Vesterdal Ingeborg Callesen Kjell Suadicani Erik Schou Rolf Björheden Antti Asikainen Nicholas Clarke Anders C. HansenAbstract
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Authors
Xurong Mei Hongmin Dong Yue Li Nicholas Clarke Daozhi Gong Weiping Hao Yingchun Li Buchun Liu Xin Ma Wei XiongAbstract
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Authors
Mei Xurong Dong Hongmin Li Yue Nicholas Clarke Gong Daozhi Hao Weiping Li Yingchun Liu Buchun Ma Xin Xiong WeiAbstract
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Authors
Mei Xurong Dong Hongmin Li Yue Nicholas Clarke Gong Daozhi Hao Weiping Li Yingchun Liu Buchun Ma Xin Xiong WeiAbstract
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Authors
Nicholas ClarkeAbstract
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Authors
Nicholas ClarkeAbstract
No abstract has been registered
Authors
Nicholas ClarkeAbstract
No abstract has been registered
Authors
Nicholas ClarkeAbstract
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Authors
Johannes Deelstra Sekhar Udaya Nagothu Per Stålnacke Mehreteab Tesfai H. Sørlie Marte Lund Edvardsen Nicholas ClarkeAbstract
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Authors
Nathalie Cools Arne Verstraeten Wendelin Weis Stefano Carnicelli Guia Cecchini Nicholas Clarke Elisabeth Graf Pannatier Jim Johnson Mathieu Jonard Henning Meesenburg Tiina M. Nieminen Gunilla Pihl Karlsson Elena Vanguelova Jörg Sintermann Lars Vesterdal Karin HansenAbstract
No abstract has been registered
Abstract
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Abstract
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Authors
Nicholas ClarkeAbstract
No abstract has been registered
Authors
Tonje Ingeborg Økland Jørn-Frode Nordbakken Holger Lange Ingvald Røsberg O. Janne Kjønaas Kjersti Holt Hanssen Nicholas ClarkeAbstract
No abstract has been registered
Authors
Yanliang Wang Tore Krogstad Jihong Liu Clarke Moritz Hallama Anne Falk Øgaard Susanne Eich-Greatorex Ellen Kandeler Nicholas ClarkeAbstract
Many arable lands have accumulated large reserves of residual phosphorus (P) and a relatively large proportion of soil P is less available for uptake by plants. Root released organic anions are widely documented as a key physiological strategy to enhance P availability, while limited information has been generated on the contribution of rhizosphere organic anions to P utilization by crops grown in agricultural soils that are low in available P and high in extractable Ca, Al, and Fe. We studied the role of rhizosphere organic anions in P uptake from residual P in four common crops Triticum aestivum, Avena sativa, Solanum tuberosum, and Brassica napus in low- and high-P availability agricultural soils from long-term fertilization field trials in a mini-rhizotron experiment with four replications. Malate was generally the dominant organic anion. More rhizosphere citrate was detected in low P soils than in high P soil. B. napus showed 74–103% increase of malate in low P loam, compared with clay loam. A. sativa had the greatest rhizosphere citrate concentration in all soils (5.3–15.2 μmol g−1 root DW). A. sativa also showed the highest level of root colonization by arbuscular mycorrhizal fungi (AMF; 36 and 40%), the greatest root mass ratio (0.51 and 0.66) in the low-P clay loam and loam respectively, and the greatest total P uptake (5.92 mg P/mini-rhizotron) in the low-P loam. B. napus had 15–44% more rhizosphere acid phosphatase (APase) activity, ~0.1–0.4 units lower rhizosphere pH than other species, the greatest increase in rhizosphere water-soluble P in the low-P soils, and the greatest total P uptake in the low-P clay loam. Shoot P content was mainly explained by rhizosphere APase activity, water-soluble P and pH within low P soils across species. Within species, P uptake was mainly linked to rhizosphere water soluble P, APase, and pH in low P soils. The effects of rhizosphere organic anions varied among species and they appeared to play minor roles in improving P availability and uptake.
Authors
Nicholas Clarke Hugh Cross Toril Drabløs Eldhuset Kjersti Holt Hanssen Ari Hietala O. Janne Kjønaas Holger Lange Jørn-Frode Nordbakken Tonje Ingeborg Økland Ingvald Røsberg Silje SkårAbstract
No abstract has been registered
Abstract
Effects of clear-cut harvesting on ground vegetation plant species diversity and their cover are investigated at two Norway spruce sites in southern Norway, differing in climate and topography. Experimental plots at these two sites were either harvested conventionally (stem-only harvesting) or whole trees including crowns, twigs and branches were removed (whole-tree harvesting), leaving residue piles on the ground for some months. We compare the number of plant species in different groups and their cover sums before and after harvesting, and between the different treatments, using non-parametric statistical tests. An overall loss of ground vegetation biodiversity is induced by harvesting and there is a shift in cover of dominant species, with negative effects for bryophytes and dwarf shrubs and an increase of graminoid cover. Differences between the two harvesting methods at both sites were mainly due to the residue piles assembled during whole-tree harvesting and the physical damage made during the harvesting of residues in these piles. The presence of the residue piles had a clear negative impact on both species numbers and cover. Pile residue harvesting on unfrozen and snow-free soil caused more damage to the forest floor in the steep terrain at the western site compared to the eastern site.
Authors
Nicholas Clarke Kjersti Holt Hanssen Jørn-Frode Nordbakken Tonje Ingeborg Økland Katarzyna WasakAbstract
No abstract has been registered
Authors
Nicholas Clarke Kjersti Holt Hanssen Jørn-Frode Nordbakken Tonje Ingeborg Økland Katarzyna WasakAbstract
No abstract has been registered
Abstract
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Authors
Jim Johnson Arne Verstraeten Henning Meesenburg Lars Vesterdal Karin Hansen Elena Vanguelova Mathieu Jonard Elisabeth Graf Pannatier Jörg Sintermann Tiina M. Nieminen Stefano Carnicelli Guia Cecchini Nicholas ClarkeAbstract
No abstract has been registered
Abstract
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Authors
Nicholas Clarke Kjersti Holt Hanssen Janka Dibdiakova Jørn-Frode Nordbakken Tonje Ingeborg ØklandAbstract
No abstract has been registered
Authors
Marta Camino-Serrano Elisabeth Graf Pannatier Sara Vicca Sebastiaan Luyssaert Mathieu Jonard Philippe Ciais Bertrand Guenet Bert Gielen Josep Peñuelas Jordi Sardans Peter Waldner Sophia Etzold Guia Cecchini Nicholas Clarke Zoran Galic Laure Gandois Karin Hansen Jim Johnson Uwe Klinck Zora Lachmanová Antti-Jussi Lindroos Henning Meesenburg Tiina M. Nieminen Tanja G. M. Sanders Kasia Sawicka Walter Seidling Anne Thimonier Elena Vanguelova Arne Verstraeten Lars Vesterdal Ivan A. JanssensAbstract
Dissolved organic carbon (DOC) in surface waters is connected to DOC in soil solution through hydrological pathways. Therefore, it is expected that long-term dynamics of DOC in surface waters reflect DOC trends in soil solution. However, a multitude of site studies have failed so far to establish consistent trends in soil solution DOC, whereas increasing concentrations in European surface waters over the past decades appear to be the norm, possibly as a result of recovery from acidification. The objectives of this study were therefore to understand the long-term trends of soil solution DOC from a large number of European forests (ICP Forests Level II plots) and determine their main physico-chemical and biological controls. We applied trend analysis at two levels: (1) to the entire European dataset and (2) to the individual time series and related trends with plot characteristics, i.e., soil and vegetation properties, soil solution chemistry and atmospheric deposition loads. Analyses of the entire dataset showed an overall increasing trend in DOC concentrations in the organic layers, but, at individual plots and depths, there was no clear overall trend in soil solution DOC. The rate change in soil solution DOC ranged between −16.8 and +23 % yr−1 (median = +0.4 % yr−1) across Europe. The non-significant trends (40 %) outnumbered the increasing (35 %) and decreasing trends (25 %) across the 97 ICP Forests Level II sites. By means of multivariate statistics, we found increasing trends in DOC concentrations with increasing mean nitrate (NO3−) deposition and increasing trends in DOC concentrations with decreasing mean sulfate (SO42−) deposition, with the magnitude of these relationships depending on plot deposition history. While the attribution of increasing trends in DOC to the reduction of SO42− deposition could be confirmed in low to medium N deposition areas, in agreement with observations in surface waters, this was not the case in high N deposition areas. In conclusion, long-term trends of soil solution DOC reflected the interactions between controls acting at local (soil and vegetation properties) and regional (atmospheric deposition of SO42− and inorganic N) scales.
Authors
Marta Camino-Serrano Elisabeth Graf Pannatier Sara Vicca Sebastiaan Luyssaert Mathieu Jonard Philippe Ciais Bertrand Guenet Bert Gielen Josep Peñuelas Jordi Sardans Peter Waldner Sophia Etzold Guia Cecchini Nicholas Clarke Galić Galic Laure Gandois Karin Hansen Jim Johnson Uwe Klinck Zora Lachmanová Antti-Jussi Lindroos Henning Meesenburg Tiina M. Nieminen Tanja G.M. Sanders Kasia Sawicka Walter Seidling Anne Thimonier Elena Vanguelova Arne Verstraeten Lars Vesterdal Ivan A. JanssensAbstract
No abstract has been registered
Authors
Nicholas ClarkeAbstract
No abstract has been registered
Authors
Lars Högbom Leena Finér Nicholas Clarke Martyn N. Futter Per Gundersen Ari Laurén Samuli Launiainen Eva RingAbstract
No abstract has been registered
Authors
Ingeborg Callesen Robert Harrison Inge Stupak Jeff Hatten Karsten Raulund-Rasmussen James Boyle Nicholas Clarke Darlene ZabowskiAbstract
No abstract has been registered
Authors
Yanliang Wang Marit Almvik Nicholas Clarke Susanne Eich-Greatorex Anne Falk Øgaard Tore Krogstad Hans Lambers Jihong Liu ClarkeAbstract
Phosphorus (P) is an important element for crop productivity and is widely applied in fertilizers. Most P fertilizers applied to land are sorbed onto soil particles, so research on improving plant uptake of less easily available P is important. In the current study, we investigated the responses in root morphology and root-exuded organic acids (OAs) to low available P (1 mM P) and sufficient P (50 mM P) in barley, canola and micropropagated seedlings of potato— three important food crops with divergent root traits, using a hydroponic plant growth system.We hypothesized that the dicots canola and tuber-producing potato and the monocot barley would respond differently under various P availabilities. WinRHIZO and liquid chromatography triple quadrupole mass spectrometry results suggested that under low P availability, canola developed longer roots and exhibited the fastest root exudation rate for citric acid. Barley showed a reduction in root length and root surface area and an increase in root-exudedmalic acid under low-P conditions. Potato exuded relativelysmall amounts of OAs under low P, while therewas a marked increase in root tips. Based on the results, we conclude that different crops show divergent morphological and physiological responses to low P availability, having evolved specific traits of root morphology and root exudation that enhance their P-uptake capacity under low-P conditions. These results could underpin future efforts to improve P uptake of the three crops that are of importance for future sustainable crop production.
Abstract
Increased forest biomass production for bioenergy will have various consequences for landscape scenery, depending on both the landscape features present and the character and intensity of the silvicultural and harvesting methods used. We review forest preference research carried out in Finland, Sweden and Norway, and discuss these findings in relation to bioenergy production in boreal forest ecosystems. Some production methods and related operations incur negative reactions among the public, e.g. stump harvesting, dense plantation, soil preparation, road construction, the use of non-native species, and partly also harvest of current non-productive forests. Positive visual effects of bioenergy production tend to be linked to harvesting methods such as tending, thinning, selective logging and residue harvesting that enhance both stand and landscape openness, and visual and physical accessibility. Relatively large differences in findings between studies underline the importance of local contextual knowledge about landscape values and how people use the particular landscape where different forms of bioenergy production will occur. This scientific knowledge may be used to formulate guiding principles for visual management of boreal forest bioenergy landscapes.
Authors
Tonje Ingeborg Økland Jørn-Frode Nordbakken Holger Lange Ingvald Røsberg O. Janne Kjønaas Kjersti Holt Hanssen Nicholas ClarkeAbstract
Whole-tree harvest (WTH), i.e. harvesting of forest residues (twigs, branches and crown tops) in addition to stems, for bioenergy purposes may lead to biodiversity loss and changes in species composition in forest ground vegetation, which in turn also will affect soil properties. Effects of clear-cut harvesting on ground vegetation have been investigated at two Norway spruce sites in southern east and western Norway, respectively, differing in climate and topography. Experimental plots at these two sites were either harvested conventionally (stem-only harvest, SOH), leaving harvest residues spread on the site,or WTH was carried out, with the residues collected into piles at the site for six - nine months prior to removal. Vegetation plots in the eastern site were established and analysed before WTH and SOH in 2008 and reanalysed after harvesting in 2010, 2012 and 2014. In the western site vegetation plots were established before WTH and SOH in 2010 and reanalysed after harvesting in 2012 and 2014 (and planned for 2016). All vegetation plots are permanently marked. Pre-as well as post-harvesting species abundances of all species in each vegetation plot were each time recorded as percentage cover (vertical projection) and subplot frequency. Environmental variables (topographical, soil physical, soil chemical, and tree variables) were recorded only once; before WTH and SOH. Effec ts of WTH and SOH on ground vegetation biodiversity and cover are presented.
Authors
Gunnhild Søgaard Aksel Granhus Belachew Gizachew Zeleke Nicholas Clarke Kjell Andreassen Rune EriksenAbstract
Miljødirektoratet utarbeidet i 2014 et kunnskapsgrunnlag for hvordan vi kan omstille Norge til et lavutslippssamfunn (Miljødirektoratet 2014). I rapporten ble en rekke tiltak i skog beskrevet. Denne rapporten er en del av neste fase av dette arbeidet, som er å utdype analysen av mulige tiltak og virkemidler. Her beskriver vi, på oppdrag fra Miljødirektoratet, et utvalg klimatiltak i skog. Det er på ingen måte noen uttømmende oversikt over klimatiltak, men dekker et utvalg som det var ønske om å belyse nærmere. Disse er belyst nærmere med hovedvekt på karbonopptak og –lagring. Betydning for andre økosystemtjenester, som for eksempel biodiversitet og friluftsliv, er ikke belyst. Hovedkonklusjonene fra dette arbeidet kan kort oppsummeres slik: Fra 1990 og frem til 2012 har et bruttoareal på 1,4 mill. daa blitt avskoget (NIR 2014). Basert på data fra Landsskogtakseringen ser vi at den viktigste årsaken er nedbygging av skogareal til ulike formål (73 % av arealet), etterfulgt av omdisponering til beite (16 %). Om lag 29 % av skogen som avvirkes, hogges før hogstmodenhetsalder. Av dette arealet utgjør hogstklasse IV 25 %, mens hogstklasse III eller yngre utgjør 4 %. Skog definert som ”yngre skog” etter forslag til revidert PEFC skogstandard utgjør 9 %. Generelt benyttes relativt skånsomme metoder for markberedning i Norge i dag, og disse er vurdert til sannsynligvis å ha liten eller ingen effekt på karbonmengder i jorda over tid og over det totale areal. Tettere planting gir høyere volumproduksjon tidlig i bestandets liv. I følge resultatkontrollen i 2013 hadde 29 % av det totale foryngelsesarealet et plantetall under anbefalt nivå i bærekraftforskriften. Framskrivningene av skogbestokningen viser at en fortsettelse av dagens praksis på årlig foryngelsesareal fra 2015 og frem til 2100 akkumulert gir 83,5 millioner tonn CO2 lavere opptak enn om arealet hadde vært plantet med anbefalt tetthet. Høyere plantetetthet gir også økt mulighet for å ta ut virke gjennom tynning. Vi mener det er potensial for økt tynningsaktivitet, uten at dette vil redusere produksjon (opptak) på lenger sikt. Tynning kan øke potensialet for mer bruk av GROT (heltretynning). Ved tynning og gjødsling kan andelen sagtømmer i det hogstmodne bestandet øke, og samtidig kan tynning være ønskelig for å lage stabile bestand som kan overholdes utover normal hogstmodenhetsalder. Uttak av hogstrester (GROT) gir råstoff til bioenergi, som kan brukes til å erstatte fossile brensler. Forutsatt høstet på en bærekraftig måte, kan uttaket av GROT sannsynligvis økes uten redusert fremtidig produksjon (opptak). En lavskjerm med bjørk over granforyngelse vil, dersom den skjøttes riktig, gi en høyere total volumproduksjon på arealet over ett omløp sammenlignet med et renbestand med gran.
Authors
Marco Ferretti Marco Calderisi Aldo Marchetto Peter Waldner Anne Thimonier Matthieu Jonard Nathalie Cools Pasi Rautio Nicholas Clarke Karin Hansen Päivi Merilä Nenad PotočićAbstract
No abstract has been registered
Authors
Peter Waldner Anne Thimonier Elisabeth Graf Pannatier Sophia Etzold Maria Schmitt Aldo Marchetto Pasi Rautio Kirsti Derome Tiina M. Nieminen Seppo Nevalainen Antti-Jussi Lindroos Päivi Merilä Georg Kindermann Markus Neumann Nathalie Cools Bruno de Vos Peter Roskams Arne Verstraeten Karin Hansen Gunilla Pihl Karlsson Hans-Peter Dietrich Stephan Raspe Richard Fischer Martin Lorenz Susanne Iost Oliver Granke Tanja G. M. Sanders Alexa Michel Hans-Dieter Nagel Thomas Scheuschner Primož Simončič Klaus von Wilpert Henning Meesenburg Stefan Fleck Sue Benham Elena Vanguelova Nicholas Clarke Morten Ingerslev Lars Vesterdal Per Gundersen Inge Stupak Mathieu Jonard Nenad Potočić Mayte MinayaAbstract
No abstract has been registered
Authors
Nicholas ClarkeAbstract
No abstract has been registered
Authors
Nicholas Clarke Per Gundersen Ulrika Jönsson-Belyazid O. Janne Kjønaas Tryggve Persson Bjarni D. Sigurdsson Inge Stupak Lars VesterdalAbstract
No abstract has been registered
Authors
Nicholas Clarke Per Gundersen Ulrika Jönsson-Belyazid O. Janne Kjønaas Tryggve Persson Bjarni D. Sigurdsson Inge Stupak Lars VesterdalAbstract
No abstract has been registered
Authors
Nicholas Clarke Per Gundersen Ulrika Jönsson-Belyazid O. Janne Kjønaas Tryggve Persson Bjarni Diðrik Sigurðsson Inge Stupak Lars VesterdalAbstract
No abstract has been registered
Authors
O. Janne Kjønaas Nicholas Clarke Toril Drabløs Eldhuset Ari Hietala Hugh Cross Kjersti Holt Hanssen Tonje Ingeborg Økland Holger Lange Jørn-Frode Nordbakken Ingvald RøsbergAbstract
Tree harvest and different harvesting methods may affect the soil carbon (C) pool in forest ecosystems. In con- ventional stem-only timber harvesting (SOH), branches and tops that are left in the forests may contribute to the build-up of the soil carbon pool. In whole-tree harvesting (WTH), inputs of organic matter from branches and tops are strongly reduced. We established field experiments at Gaupen, SE and Vindberg, SW Norway, to study the short-term effects of SOH and WTH on processes affecting the accumulation and loss of soil C. Logging residues on the WTH plots were collected in piles that were removed after 6 months, rendering two sub treatments (WTH- pile and WTH-removal areas). We weighed selected trees and logging residues, surveyed understorey biomass production, quantified pre-harvest soil C and nutrient pools down to 30 cm. Soil respiration was measured and soil water sampled monthly during the growing season, while temperature and moisture were measured continuously. Organic and mineral horizons were incubated at different temperatures to estimate potential C and N mineraliza- tion, and deep sequencing of the ITS2 barcode region of fungal DNA was performed on the samples. Litterbags were deployed in the SOH plots. The logging residues amounted to 2.2-2.4 kg C m-2 At Gaupen, the mean in situ soil respiration rates increased following harvest with all treatments, but were significantly higher in WTH-pile and SOH relative to the WTH- removal areas in the first year as well as the fourth year of treatment. The former rates included aboveground decomposing needles and twigs but excluded coarser branches. The observed increase in the WTH-removal areas may be related to decomposing roots, as well as to increased C mineralization partly due to the higher soil tem- peratures following harvest. Soil temperature was the single most important factor explaining the variability in soil respiration rates over all treatments. At Vindberg, a decrease in soil respiration was observed with all treatments in the second and third years following harvest. At both sites, decomposition of logging residues from needles was more rapid relative to twigs and fine roots. The decomposing residues released a substantial amount of nitrogen which was gradually reflected in the soil water at 30 cm soil depth. A considerable increase in the NO3-N concen- tration also in the WTH-removal areas in the second year following harvest suggests an increase in N availability from decomposing fine roots and/or soil organic matter. The increased N availability in the WTH-removal areas was supported by results from short term lab incubations of undisturbed soil from the forest floor. The changes in the WTH-removal areas were also reflected in the soil fungal diversity: saprophytic ascomycetes on decaying plant material showed a striking increase in all treatments. For the WTH-removal areas, this may, again, be related to the increased input of root litter; however, the decrease in mycorrhizal basidiomycete species and the vigorous increase of ascomycetes following harvest may also affect the C mineralization of soil organic matter.
Authors
Lars Vesterdal Nicholas Clarke Bjarni D. Sigurdsson Helena M Stefánsdóttir O. Janne Kjønaas Per Gundersen Inge Stupak Teresa Gómez de la Bárcena Lars Pødenphant KiærAbstract
No abstract has been registered
Authors
Inge Stupak Karin Hansen Eva Ring Karsten Raulund-Rasmussen Ingeborg Callesen Nicholas ClarkeAbstract
No abstract has been registered
Authors
Peter Waldner Aldo Marchetto Anne Thimonier Maria Schmitt Michela Rogora Oliver Granke Volker Mues Karin Hansen Gunilla Pihl Karlsson Daniel Žlindra Nicholas Clarke Arne Verstraeten Andis Lazdins Claus Schimming Carmen Iacoban Antti-Jussi Lindroos Elena Vanguelova Sue Benham Henning Meesenburg Manuel Nicolas Anna Kowalska Vladislav Apuhtin Ulle Napa Zora Lachmanová Ferdinand Kristoefel Albert Bleeker Morten Ingerslev Lars Vesterdal Juan Molina Uwe Fischer Walter Seidling Mathieu Jonard Philip O'Dea James Johnson Richard Fischer Martin LorenzAbstract
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Abstract
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Authors
Per Gundersen Shimon Ozeri Lars Vesterdal Teresa Gómez de la Bárcena Andis Lazdins Bjarni D. Sigurdsson Tryggve Persson Per Bengtsson Cecilia Akselsson Nicholas ClarkeAbstract
No abstract has been registered
Authors
Per Gundersen Shimon Ozeri Ginzburg Lars Vesterdal Teresa Gómez de la Bárcena Bjarni D. Sigurdsson Helena M Stefánsdóttir Edda S Oddsdottir Nicholas Clarke O. Janne Kjønaas Tryggve Persson Göran Ågren Bengt Olsson Mats Fröberg Erik Karltun Riitta Hyvönen Olsson Cecilia Akselsson Per Bengtsson Salim Belyazid Håkan Wallander Andis Lazdins Zane Libiete Dagnija LazdinaAbstract
No abstract has been registered
Authors
Yan-liang Wang Sissel Haugslien Marit Almvik Nicholas Clarke Anne Falk Øgaard Jihong Liu ClarkeAbstract
No abstract has been registered
Authors
Giulia Carriero Juha-Pekka Tuovinen Nicholas Clarke Giorgio Matteucci Rainer Matyssek Gerhard Wieser Teis Nørgaard Mikkelsen Richard Fischer Pavel Cudlin Yusuf Serengil Fabio Boscaleri Carlo Calfapietra Zhaozhong Feng Elena PaolettiAbstract
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Authors
Marta Camino-Serrano Bert Gielen Sebastiaan Luyssaert Philippe Ciais Sara Vicca Bertrand Guenet Bruno de Vos Nathalie Cools Bernhard Ahrens M. Altaf Arain Werner Borken Nicholas Clarke Beverley Clarkson Thomas Cummins Axel Don Elisabeth Graf Pannatier Hjalmar Laudon Tim Moore Tiina M. Nieminen Mats B. Nilsson Matthias Peichl Luitgard Schwendenmann Jan Siemens Ivan A. JanssensAbstract
No abstract has been registered
Authors
Yanliang Wang Sissel Haugslien Marit Almvik Nicholas Clarke Anne Falk Øgaard Jihong Liu ClarkeAbstract
No abstract has been registered
Authors
Yanliang Wang Sissel Haugslien Marit Almvik Nicholas Clarke Anne Falk Øgaard Jihong Liu ClarkeAbstract
No abstract has been registered
Authors
Yanliang Wang Sissel Haugslien Marit Almvik Nicholas Clarke Anne Falk Øgaard Jihong Liu ClarkeAbstract
No abstract has been registered
Authors
Nicholas ClarkeAbstract
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Authors
Tonje Ingeborg Økland Jørn-Frode Nordbakken Holger Lange Ingvald Røsberg O. Janne Kjønaas Nicholas Clarke Kjersti Holt HanssenAbstract
No abstract has been registered
Authors
Tonje Ingeborg Økland Jørn-Frode Nordbakken Holger Lange Ingvald Røsberg O. Janne Kjønaas Kjersti Holt Hanssen Nicholas ClarkeAbstract
No abstract has been registered
Authors
Karen Refsgaard John Marshall Bryden Biancha Cavicchi Nicholas Clarke Stig Strandli Gezelius Valborg KvakkestadAbstract
No abstract has been registered
Authors
Nicholas Clarke Toril Drabløs Eldhuset Kjersti Holt Hanssen Ari Hietala O. Janne Kjønaas Holger Lange Jørn-Frode Nordbakken Tonje Ingeborg Økland Ingvald RøsbergAbstract
No abstract has been registered
Authors
Nicholas Clarke Toril Drabløs Eldhuset Kjersti Holt Hanssen Ari Hietala O. Janne Kjønaas Holger Lange Jørn-Frode Nordbakken Tonje Ingeborg Økland Ingvald RøsbergAbstract
No abstract has been registered
Authors
O. Janne Kjønaas Nicholas Clarke Toril Drabløs Eldhuset Kjersti Holt Hanssen Ari Hietala Holger Lange Jørn-Frode Nordbakken Tonje Ingeborg Økland Ingvald RøsbergAbstract
No abstract has been registered
Authors
O. Janne Kjønaas Nicholas Clarke Toril Drabløs Eldhuset Ari Hietala Hugh Cross Tonje Ingeborg Økland Jørn-Frode Nordbakken Holger Lange Ingvald Røsberg Kjersti Holt HanssenAbstract
No abstract has been registered
Authors
Elena Curcio Michele Innangi Marta Alvarez Romero Arne Verstraeten Nicholas Clarke Antonietta Fioretto Stefania PapaAbstract
No abstract has been registered
Authors
Marco Ferretti Marco Calderisi Aldo Marchetto Peter Waldner Anne Thimonier Matthieu Jonard Nathalie Cools Pasi Rautio Nicholas Clarke Karin Hansen Päivi Merilä Nenad PotocicAbstract
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Authors
Alina Danielewska Nicholas Clarke Janusz Olejnik Karin Hansen Wim de Vries Lars Lundin Juha Pekka Tuovinen Richard Fischer Marek Urbaniak Elena PaolettiAbstract
Of a wide variety of international forest research and monitoring networks, several networks are dedicated to the effects of climate change on forests, while the effects of anthropogenic pollutants on forests have been a major area for both monitoring and research for decades. The large amounts of data already obtained within existing monitoring programmes and large-scale international projects can be used to increase understanding of the state and potential of forest mitigation and adaptation to climate change in a polluted environment, and a major challenge now is to evaluate and integrate the presently available databases. We present a meta-database with the main goal to highlight available data and integrate the information about research and monitoring of selected European Research and Monitoring Networks (ERMNs). Depending on the selected ERMNs, the list of variables and the measurement units differ widely in the databases. As a result, activities related to the identification, evaluation and integration of the presently available databases are important for the scientific community. Furthermore, and equally important, the recognition of current knowledge gaps and future needed research is made easier. This analysis suggests that: ground-level ozone is under-investigated, although it is one of the pollutants of greatest concern to forests; in addition to CO2, long-term other greenhouse gasses (GHG) flux measurements should be carried out; there is still a need of improving links between monitoring of atmospheric changes and impacts on forests; research-oriented manipulative experiments in the forests are missing.
Authors
Karin Hansen Anne Thimonier Nicholas Clarke Jeroen Staelens Daniel Žlindra Peter Waldner Aldo MarchettoAbstract
No abstract has been registered
Editors
Rainer Matyssek Nicholas Clarke Pavel Cudlin Teis Nørgaard Mikkelsen Juha-Pekka Tuovinen Gerhard Wieser Elena PaolettiAbstract
No abstract has been registered
Authors
Rainer Matyssek Nicholas Clarke Pavel Cudlin Teis Nørgaard Mikkelsen Juha-Pekka Tuovinen Gerhard Wieser Elena PaolettiAbstract
No abstract has been registered
Authors
Rainer Matyssek Thomas Knoke Nicholas Clarke Pavel Cudlin Teis Nørgaard Mikkelsen Juha-Pekka Tuovinen Gerhard Wieser Elena PaolettiAbstract
No abstract has been registered
Abstract
Information on tree species effects on soil organic carbon (SOC) stocks is scattered and there have been few attempts to synthesize results for forest floor and mineral soil C pools. We reviewed and synthesized current knowledge of tree species effects on SOC stocks in temperate and boreal forests based on common garden, retrospective paired stand and retrospective single-tree studies. There was evidence of consistent tree species effects on SOC stocks. Effects were clearest for forest floor C stocks (23 of 24 studies) with consistent differences for tree genera common to European and North American temperate and boreal forests. Support for generalization of tree species effects on mineral soil C stocks was more limited, but significant effects were found in 13 of 22 studies that measured mineral soil C. Proportional differences in forest floor and mineral soil C stocks among tree species suggested that C stocks can be increased by 200–500% in forest floors and by 40–50% in top mineral soil by tree species change. However, these proportional differences within forest floors and mineral soils are not always additive: the C distribution between forest floor and mineral soil rather than total C stock tends to differ among tree species within temperate forests. This suggests that some species may be better engineers for sequestration of C in stable form in the mineral soil, but it is unclear whether the key mechanism is root litter input or macrofauna activity. Tree species effects on SOC in targeted experiments were most consistent with results from large-scale inventories for forest floor C stocks whereas mineral soil C stocks appeared to be stronger influenced by soil type or climate than by tree species at regional or national scales. Although little studied, there are indications that higher tree species diversity could lead to higher SOC stocks but the role of tree species diversity per se vs. species identity effects needs to be disentangled in rigorous experimental designs. For targeted use of tree species to sequester soil C we must identify the processes related to C input and output, particularly belowground, that control SOC stock differences. We should also study forms and stability of C along with bulk C stocks to assess whether certain broadleaves store C in more stable form. Joint cooperation is needed to support syntheses and process-oriented work on tree species and SOC, e.g. through an international network of common garden experiments.
Authors
Tonje Ingeborg Økland Jørn Frode Nordbakken Holger Lange Ingvald Røsberg Janne O. Kjønaas Kjersti Holt Hanssen Toril Drabløs Eldhuset Nicholas ClarkeAbstract
No abstract has been registered
Authors
Nicholas ClarkeAbstract
No abstract has been registered
Authors
Nicholas ClarkeAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Samuli Launiainen Martyn N. Futter David Ellison Nicholas Clarke Leena Finér Lars Högbom Ari Laurén Eva RingAbstract
No abstract has been registered
Authors
Yanliang Wang Sissel Haugslien Marit Almvik Nicholas Clarke Anne Falk Øgaard Jihong Liu ClarkeAbstract
No abstract has been registered
Authors
Peter Waldner Anne Thimonier Maria Schmitt Aldo Marchetto Michela Rogora Oliver Granke Volker Mues Karin Hansen Gunilla Pihl-Karlsson Daniel lindra Nicholas Clarke Arne Verstraeten Andis Lazdins Claus Schimming Carmen Iacoban Antti-Jussi Lindroos Elena Iordanova Vanguelova Sue Benham Henning Meesenburg Manuel Nicholas Anna Kowalska Vladislav Apuhtin Ulle Nappa Zora Lachmanová Markus Neumann Albert Bleeker Morten Ingerslev Juan Molina Lars Vesterdal Walter Seidling Uwe Fischer Richard Fischer Martin LorenzAbstract
Atmospheric deposition to forests has been monitored in the frame of the ICP Forests programme with sampling and analyses of bulk and throughfall deposition at several hundred forested Level II plots for more than 15 years now. Current deposition of inorganic nitrogen and sulphate is highest in Northern Central Europe as well as in some regions in southern parts. In this study we compared linear regression and MannKendall trend analyses techniques. The choice of method had an influence on the number of trends identified as being significant. We showed that the minimal detectable trends can be estimated with the mean short term temporal variability of the deposition, which is to a large extent due to meteorological variations, such as the precipitation and circulation patterns. The overall decreasing trends for inorganic N and SO42- in the past decade of about 3% and 6% require time series of about 10 and 6 years respectively to detect a trend on a plot with statistical significance. Past reduction of human emission reduced atmospheric deposition of acidifying and eutrophying compounds. This could be confirmed due to the availability of long-term data series. However, further reductions are required to reduce deposition to forests below critical loads for the whole of Europe.
Abstract
No abstract has been registered
Authors
Alina Danielewska Elena Paoletti Nicholas Clarke Janusz Olejnik Marek Urbaniak Marcin Baran Pawel Siedlecki Karin Hansen Lars Lundin Wim de Vries Teis Nørgaard Mikkelsen Sophie Dillen Richard FischerAbstract
Aim of study: The main aim of the work was to summarize availability, quality and comparability of on-going European Research and Monitoring Networks (ERMN), based on the results of a COST FP0903 Action questionnaire carried out in September 2010 and May 2012. Area of study: The COST Action FP0903 involves 29 European countries and 4 non-COST institutions from USA, Morocco and Tunisia. In this study, the total of 22 replies to the questionnaire from 18 countries were included. Materials and methods: Based on the feedback from the Action FP0903 countries, the most popular European Networks were identified. Thereafter, the access to the network database, available quality assurance/quality control procedures and publication were described. Finally, the so-called “Supersites” concept, defined as a “highly instrumented research infrastructure, for both research and monitoring of soil-plant-atmosphere interactions” was discussed. Main results: The result of the survey indicate that the vast majority of the Action FP0903 countries participate in the International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forest (ICP Forest). The multi-disciplinary International Cooperative Programme on Integrated Monitoring of Air Pollution Effects on Ecosystems (ICPIM) is the second most widespread forest programme. Research highlights: To fully understand biochemical cycles in forest ecosystems, long-term monitoring is needed. Hence, a network of “Supersites”, is proposed. The application of the above infrastructure can be an effective way to attain a better integration of research and monitoring networks at forest sites in Europe. Key words: supersites; European Research Monitoring Networks; harmonization; forest.
Abstract
No abstract has been registered
Authors
Inge Stupak Brian Titus Nicholas Clarke Tat Smith Andis Lazdins Iveta Varnagiryte-Kabasinskiene Kestutis Armolaitis Milica Peric Claudia GuidiAbstract
No abstract has been registered
Abstract
This study examines already existing guidelines for the sustainable removal of slash from forests for bioenergy use. Existing guidelines from some countries, states and provinces with forest ecosystems comparable to Norways (Sweden, Finland, the U.K., Ireland, Minnesota, New Hampshire and British Columbia) are compared with the Norwegian Living Forests (LF) and Debio (ecological forestry) guidelines. The aim is to identify areas where the Norwegian guidelines could be further developed.
Abstract
This report has been prepared in the frame of Work Package 3 (Policy) of the Interreg IVB project Bioenergy Promotion. The main rationale of this work package is to support the development of coherent national and (sub)regional policies promoting the sustainable production and consumption of bioenergy. The purpose of the country policy assessment report is to describe the main promotional policies and support schemes for bioenergy and to assess to what extent national policy frameworks contribute to Sustainable Development and integrate related sustainability principles and criteria. At present and in the foreseeable future, the main source of raw materials for bioenergy in Norway is likely to be the forests. However, waste from agriculture, households and industry is another promising source. Investment support needs to be continued, at least at present levels. The main bottlenecks for increased use of bioenergy in Norway are economic, so economic support is necessary. Further development of the standard for sustainable forestry is required, in order to take into account aspects that are not yet covered (see above under Point 3.5). However, there is currently disagreement between the parties to the Living Forests standard, so revision is not likely to take place soon. Current research is being carried out, for example in CenBio and the project “Ecological consequences of increased biomass removal from forests in Norway” on the effects of whole-tree harvesting compared to stem-only harvesting on soil nutrients, carbon stocks, ground vegetation and regeneration). In addition, work is being carried out to study the applicability under Norwegian conditions of the guidelines of other countries such as Sweden, Finland, the UK and Ireland and to prepare preliminary guidelines for Norwegian forestry. There is disagreement on the likely short-term effects of biomass harvesting for bioenergy on carbon sequestration in forest ecosystems (see above under 5.2) and this needs to be further studied. In their present form, the binding EU sustainability criteria for biofuels/bioliquids should not be extended to solid/gaseous biomass used for electricity and heating/cooling. Some changes are necessary to take account of specific conditions e.g. in forestry. For example, it is stated in Point 4 of Article 17 of the Renewable Energy Directive that biofuels and bioliquids shall not be obtained from land that was continuously forested in January 2008 and is no longer continuously forested. It is unclear how this would affect clear-cuts. Also, in Point C7 of Annex V, the 20-year period for calculating carbon stock changes is completely unrealistic for forestry (although this refers to land-use change and it could be argued that felling is not land-use change if the land is used for forest afterwards; this should be clarified). These aspects of the Renewable Energy Directive are already problematic if forest biomass is to be used for biofuels or bioliquids.
Authors
Nicholas ClarkeAbstract
No abstract has been registered
Authors
Nicholas ClarkeAbstract
This report aims to summarise briefly the findings in the scientific literature concerning the effect of both stem-only and whole-tree harvesting on soil carbon stocks. Although the findings reported by previous authors vary, it is possible to draw some general conclusions about the effect of harvesting on soil carbon, and on whether whole-tree harvesting has a greater effect than stem-only harvesting. In general it appears that the organic C content in the soil’s organic layer is reduced after stem-only harvesting, sometimes by as much as 50%. This reduction has been explained in several ways. After a period of maybe 20 years, the carbon content of the organic layer starts to increase again. In the mineral soil a reduction is not always apparent and the C content can even increase, probably because of the incorporation of residues into the soil. Some studies have shown that this increase is short-lived, while others have found a longer-term increase. Unsurprisingly, thinning appears to affect the soil carbon content much less than clear-cutting; the effect tends to be proportional to the thinning intensity. The soil carbon content appears to be higher after selection cutting than after clear-cutting. Studies comparing effects of whole-tree harvest with those of stem-only harvest have tended to show smaller carbon contents in the mineral soil after whole-tree harvest than after stem-only harvest, although once again results vary greatly. There are many factors affecting soil C content and thus accounting for the observed differences, including temperature, moisture content, and harvesting type. Variation in the results obtained may depend on site-specific factors such as site nutrient status, especially with regard to the most common limiting nutrient nitrogen, which will affect growth in the next rotation. Making sure there are enough nutrients available, if necessary by compensatory fertilisation, will improve carbon sequestration in both trees and soil.
Authors
Nicholas ClarkeAbstract
This report presents preliminary results from investigations on changes in soil water chemistry after stem-only and whole-tree harvesting at a site in eastern Norway, with emphasis on major nutrients, pH and dissolved organic carbon. For stem-only harvesting (SOH) and whole-tree harvesting where slash had been piled (WTH pile), concentrations of nitrate, calcium, magnesium, and potassium peaked in the second year after harvesting and again, but lower, in the third. Ammonium concentrations peaked in the year after harvesting. There was slight acidification after harvesting. No increased concentrations of dissolved organic carbon were observed. In general, trends were similar between SOH and WTH piles, compared to where slash had been removed to form the piles. Peaks in concentrations were higher for WTH piles compared to SOH. The results agree well with results from other field measurements reported in the scientific literature.
Abstract
No abstract has been registered
Authors
Nina Elisabeth Nagy Harald Kvaalen Monica Fongen Carl Gunnar Fossdal Nicholas Clarke Halvor Solheim Ari HietalaAbstract
Pathogen challenge of tree sapwood induces the formation of reaction zones with antimicrobial properties such as elevated pH and cation content. Many fungi lower substrate pH by secreting oxalic acid, its conjugate base oxalate being a reductant as well as a chelating agent for cations. To examine the role of oxalic acid in pathogenicity of white-rot fungi, we conducted spatial quantification of oxalate, transcript levels of related fungal genes, and element concentrations in heartwood of Norway spruce challenged naturally by Heterobasidion parviporum. In the pathogen-compromised reaction zone, upregulation of an oxaloacetase gene generating oxalic acid coincided with oxalate and cation accumulation and presence of calcium oxalate crystals. The colonized inner heartwood showed trace amounts of oxalate. Moreover, fungal exposure to the reaction zone under laboratory conditions induced oxaloacetase and oxalate accumulation, whereas heartwood induced a decarboxylase gene involved in degradation of oxalate. The excess level of cations in defense xylem inactivates pathogen-secreted oxalate through precipitation and, presumably, only after cation neutralization can oxalic acid participate in lignocellulose degradation. This necessitates enhanced production of oxalic acid by H. parviporum. This study is the first to determine the true influence of white-rot fungi on oxalate crystal formation in tree xylem.
Authors
Nicholas Clarke Richard Fischer Wim De Vries Lars Lundin Dario Papale Timo Vesala Päivi Merilä Giorgio Matteucci Michael Mirtl David Simpson Elena PaolettiAbstract
Data from existing monitoring programmes such as ICP Forests, ICP Integrated Monitoring and EMEP, as well as from large-scale international projects such as CarboEurope IP and NitroEurope, can be used to answer questions about the impacts of air pollution and climate change on forest ecosystems and the feedbacks of forest to climate. However, for full use to be made of the available data, a number of questions need to be answered related to the availability, accessibility, quality and comparability of the data. For example, how can these databases be accessed, e.g., freely, over the internet, on request, by authorisation? How should intellectual property rights be protected, while improving access to data? What possibilities exist for harmonisation? Which quality assurance/quality control (QA/QC) procedures have been used and for how long? These and other relevant questions are discussed.
Authors
Hans Dieter Nagel Thomas Scheuschner Angela Schlutow Oliver Granke Nicholas Clarke Richard FischerAbstract
Based on intensive forest monitoring data, critical loads for acidification and eutrophication as well as their exceeedances were modelled for 107 Level II plots using the simple mass balance approach. Dynamic modelling using the VSD model was carried out for 77 plots using different deposition scenarios.Results show widespread soil acidification in the year 1980 with nearly 60% of the plots affected by critical load exceedances. A continued positive future development until 2020 is clearly visible, leading to full protection at least under the most ambitious deposition scenario.Critical loads for nutrient nitrogen were exceeded on 60% of the plots in 1980 and continue to be so in 2020 on between 10 and 30% of the plots depending on the scenario. Dynamic modelling shows that soil solution pH can recover to pre-industrial values but that over the all the 77 plots the C:N ratio shows a continuous decrease until 2050.A comparison with to measured solid soil pH from large scale plots confirms recovery for acidified soils until 2008 but shows increased acidification on soils with pH above 4.0. and points to the fact that full recovery from acidification will take decades. Decreasing C:N and continued exceedance of critical loads for nutrient nitrogen point to soil eutrophication as a major and continued area of concern.
Abstract
We used two datasets of 14C analyses of archived soil samples to study carbon turnover in O horizons from spruce dominated old-growth stands on well-drained podzols in Scandinavia. The main data set was obtained from archived samples from the National Forest Soil Inventory in Sweden and represents a climatic gradient in temperature. Composite samples from 1966, 1972, 1983 and 2000 from four different regions in a latitude gradient ranging from 57 to 67º N were analysed for 14C content. Along this gradient the C stock in the O horizon ranges from 2.1 kg m-2 in the north to 3.7 kg m-2 in the southwest. The other data set contains 14C analyses from 1986, 1987, 1991, 1996 and 2004 from the O horizons in Birkenes, Norway. Mean residence times (MRT) were calculated using a two compartment model, with a litter decomposition compartment using mass loss data from the literature for the threefirst years of decomposition and a humus decomposition compartment with a fitted constant turnover rate. We hypothesized that the climatic gradient would result in different C turnover in different parts of the country between northern and southern Sweden. The use of archived soil samples was very valuable for constraining the MRT calculations, which showed that there were differences between the regions. Longest MRT was found in the northernmost region (41 years), with decreasing residence times through the middle (36 years) and central Sweden (28 years), then again increasing in the southwestern region (40 years). The size of the soil organic carbon (SOC) pool in the O horizon was mainly related to differences in litter input and to a lesser degree to MRT. Because N deposition leads both to larger litter input and to longer MRT, we suggest that N deposition contributes significantly to the latitudinal SOC gradient in Scandinavia, with approximately twice as much SOC in the O horizon in the south compared to the north. The data from Birkenes was in good agreement with the Swedish dataset with MRT estimated to 34 years.
Abstract
We used two datasets of 14C analyses of archived soil samples to study carbon turnover in O horizons from spruce dominated old-growth stands on well-drained podsols in Scandinavia. The main data set was obtained from archived samples from the National Forest Soil Inventory in Sweden and represents a climatic gradient in temperature. Composite samples from 1966, 1972, 1983 and 2000 from four different regions in a latitude gradient ranging from 57 to 67oN were analysed for 14C content. Along this gradient the C stock in the O horizon ranges from 2.1 kg m-2 in the north to 3.7 kg m-2 in the southwest. The other data set contains 14C analyses from 1986, 1987, 1991, 1996 and 2004 from the O horizons in Birkenes, Norway. Mean residence times (MRT) were calculated using a two compartment model, with a litter decomposition compartment using mass loss data from the literature for the three first years of decomposition and a humus decomposition compartment with a fitted constant turnover rate. We hypothesized that the climatic gradient would result in different C turnover in different parts of the country between northern and southern Sweden. The use of archived soil samples was very valuable for constraining the MRT calculations, which showed that there were differences between the regions. Longest MRT was found in the northernmost region (41 years), with decreasing residence times through the middle (36 years) and central Sweden (28 years), then again increasing in the southwestern region (40 years). The size of the soil organic carbon (SOC) pool in the O horizon was mainly related to differences in litter input and to a lesser degree to MRT. Because N deposition leads both to larger litter input and to longer MRT, we suggest that N deposition contributes significantly to the latitudinal SOC gradient in Scandinavia, with approximately twice as much SOC in the O horizon in the south compared to the north. The data from Birkenes was in good agreement with the Swedish dataset with MRT estimated to 34 years.
Abstract
The main task of the C1-Dep-22(SI) action was to compare national throughfall collectors with a harmonized collector which was designed according to the requirements of the WMO. The action spread onthe took place in very different climate zones and vegetation, and included a very different types of national collectors with different sampling procedures. The number of harmonized throughfall collectors was 30 for all participants. The spatial arrangement in the plot, sampling times, sampling and cleaning procedures, bulking of the subsamples and chemical analysis procedures were in all cases the national procedures. The time when the precipitation was in the form of snow was excluded from the sampling periods. The associated beneficiaries reported the amounts of the precipitation per collector and the results from chemical analysis per pooled sample. The measured quantities were compared for different types of forest or main tree species. The deviations between collectors were lower in the plots with the broadleaf trees than in the plots with conifers as the main tree species. The median deviations for conifers and for broadleaves trees is not significantly different from zero. Except in a few cases, a good agreement in the amount of precipitation was found between the national and harmonized collectors for both throughfall and bulk precipitation. In a few incidents this was not the case but we assume that where this was not the case, this was due to happened in extreme weather conditions e. g. heavy storms. Also good agreement was also found within for the chemical composition of the solutions, gathered with different types of collectors. Again, there were some deviations limited to on single occasions. It was found that the harmonized collectors were attractive to birds and thus a bird ring is a must in this (white) -coloured version of the collector. Chemical analysis (chemical composition) together with the collected amount of the solution depends on give the total deposition values. It was made a close up to the deposition values of ammonium-nitrogen, nitrate-nitrogen and sulphate-sulphur were compared in detail. For ammonium-nitrogen no bigger difference was found for the one-year deposition values except in one case what which turned out to be almost certainly a consequence of birds activity. Differences in all other cases were no more than 0.3 g m-2 yr-1. For nitrate-nitrogen smaller deviations were found but in none of the case was the difference was in total annual deposition higher than 0.3 g m-2 yr-1. For sulphate-sulphur good agreement was found for all associated beneficiaries except two. One of the Possible reasons could be in the difference of in the ability in collecting dry deposition and/or the total area which contributes to the capturing area for dry deposition. Despite their heterogeneity and some unlack of adaptation for representative sampling at the plot scale, the national devices for throughfall collection gave comparable results infor throughfall deposition to the harmonized, optimal collectors. In conclusion national throughfall collection devices can be maintained to ensure the continuity of the time series in deposition monitoring. And to improve the harmonized collector even more, problems with the possible blockages of the tube at the bottom of the funnel because of debris should be solved.
Abstract
No abstract has been registered
Authors
Richard Fischer Wenche Aas W. De Vries Nicholas Clarke Pavel Cudlin David Leaver Lars Lundin Giorgio Matteucci Rainer Matyssek Teis Nørgaard Mikkelsen Michael Mirtl Yasemin Öztürk Dario Papale Nenad Potocic David Simpson Juha Pekka Tuovinen Timo Vesala Gerhard Wieser Elena PaolettiAbstract
Science-based approaches in addressing future risks and challenges for forests require close collaboration among the communities operating different monitoring and research networks as well as experts in process and large-scale modelling. Results of the COST FP0903 conference which took place in October 2010 in Rome, reveal valuable results from different European forest monitoring and research networks. However, the need for closer integration of these activities is obvious. In this paper, representatives from major European networks recommend a new approach for forest monitoring and research in Europe, based on a reasonable number of highly instrumented “supersites” and a larger number of intensive monitoring plots linked to these. This system needs to be built on existing infrastructures but requires increased coordination, harmonisation and a joint long term platform for data exchange and modelling.
Abstract
In recent years the harmonization of methods in the frame of the International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) operating under the UNECE Convention on Long-range Transboundary Air Pollution (CLRTAP) has been intensified. Among the C-actions of the FutMon project (LIFE07 ENV/D/000218; 2009-2010) the C1-Dep-22(SI) action was established with the goal to harmonize and develop the deposition monitoring procedures and sampling methods. The sampling equipment, spatial design of sampling plots and sampling frequency throughout Europe vary considerably. Therefore a step-by-step approach was made where the harmonized sampling equipment was developed and tested first. The selected collectors were installed at one observation plot of each participating country where measurements of throughfall and bulk deposition were run in parallel with the national collectors for a period of one year. To evaluate the agreement between methods, different statistical analyses were used including Altman-Bland plots, model II regression, and repeated measures ANOVA. Preliminary results from the “Intensive forest ecosystem monitoring plot” plot Brdo in NW Slovenia show a good agreement between national and harmonized bulk (both funnel-type) collectors, while comparison of throughfall measurements indicates systematic bias between harmonized (funnel-type) and national (gutter-type) collectors.
Authors
Martin Lorenz Nicholas Clarke Elena Paoletti Andrzej Bytnerowicz Nancy Grulke Natalia Lukina Hiroyuki Sase Jeroen StaelensAbstract
No abstract has been registered
Authors
Aldo Marchetto Rosario Mosello Gabriele A. Tartari Kirsti Derome Nils König Nicholas Clarke Anna KowalskaAbstract
A second Working Ring Test (WRT) was organised within the framework of the EU/Life+ FutMon Project (`Further Development and Implementation of an EU-level Forest Monitoring System`, LIFE07 ENV/D/000218), to evaluate the overall performance of the laboratories responsible for analysing atmospheric deposition and soil solution samples in European forests, and to verify improvements in the analytical quality resulting from the QA/QC work carried out in the laboratories which participated in previous WRTs organized in the framework of the UN/ECE ICP Forests Monitoring Programme. The WRT was carried out in accordance with International ISO and ILAG guide proficiency test both for sample preparation and numerical elaboration of the results. Five natural atmospheric deposition and soil solution samples and 3 synthetic solutions were distributed to 42 laboratories for analysis using their routine methods for the following variables: pH, conductivity, calcium, magnesium, sodium, potassium, ammonium, sulphate, nitrate, chloride, total alkalinity, total dissolved nitrogen (TDN), dissolved organic carbon (DOC). Two tolerable limits were defined for each variable on the basis of the measured value, the results of previous WRTs, a comparison with the Data Quality Objectives of other international networks, and the importance of the variable in deposition and soil solution monitoring. In the ring test 12% of the results from all the laboratories did not fall within the tolerable limits. This enabled us to identify those variables and laboratories for which improvements in analytical performance are required. The results of the exercise clearly show that the use of data check procedures, as described in the ICP Forests manual for sampling and analysis of atmospheric deposition, makes it possible to detect the presence of inaccurate or outlying results, and would therefore greatly improve the overall performance of the laboratories. A discussion of the improvement of the results in this WRT compared to the previous WRTs is also included, showing a relevant improvent for several variables and underlining the importance of participating to these exercises for the overall analytical quality of the monitoring network.
Authors
Miroslav Matucha Nicholas Clarke Zora Lachmanová Sandor T. Forczek Květoslava Fuksová Milan GryndlerAbstract
Chlorine - one of the most widespread elements on the Earth - is present in the environment as chloride ion or bound to organic substances. The main source of chloride ions is the oceans while organically bound chlorine (OCl) comes from various sources, including anthropogenic ones. Chlorinated organic compounds were long considered to be only industrial products; nevertheless, organochlorines occur plentifully in natural ecosystems. However, recent investigations in temperate and boreal forest ecosystems have shown them to be products of biodegradation of soil organic matter under participation of chlorine. It is important to understand both the inorganic and organic biogeochemical cycling of chlorine in order to understand processes in the forest ecosystem and dangers as a result of human activities, i.e. emission and deposition of anthropogenic chlorinated compounds as well as those from natural processes. The minireview presented below provides a survey of contemporary knowledge of the state of the art and a basis for investigations of formation and degradation of organochlorines and monitoring of chloride and organochlorines in forest ecosystems, which has not been carried out in the Czech Republic yet.
Abstract
Concentrations of dissolved organic carbon (DOC) in throughfall and soil solutions at 5, 15 and 40-cm depth were studied in 16 Norway spruce and two Scots pine plots throughout Norway between 1996 and 2006 (Wu et al. 2010a). Average DOC concentrations ranged from 2.3 to 23.1 mg/l and from 1.1 to 53.5 mg/l in throughfall water and soil solutions, respectively. Concentrations of DOC in throughfall and soil waters varied seasonally at most plots with peaks in the growing season. In contrast to reported positive long-term trends in DOC concentrations in surface waters between 1986 and 2003, soil water data from 1996 to 2006 showed largely negative trends in DOC concentrations and no significant trends in throughfall. However, regression analysis for individual sites, particularly at 5- and 15-cm soil depths, showed that DOC concentrations in soil water were significantly and negatively related to non-marine sulphate and chloride. Further studies were carried out on dissolved organic nitrogen (DON, Wu et al. 2010b). Dissolved organic nitrogen (DON) concentrations were significantly and positively correlated to DOC concentrations in throughfall (r2=0.72, p<0.0001) and soil water at 5, 15, and 40 cm (r2=0.86, 0.32, and 0.84 and p<0.0001, 0.04, and <0.0001, respectively). At most sites, the annual median DOC/DON ratio in throughfall ranged from 20.3 to 55.5, while values in soil water were higher, ranging from 24.5 to 81.3 but gradually decreasing with soil depth. DON concentrations varied seasonally in throughfall at many plots and in soil water at 5 cm depth at one plot only, with higher values in the growing season, but there was no noticeable seasonality at greater depth. The ratios of DOC/DON in soil water were significantly positively related to the C/N ratio in soil at the same depth. Above-ground litter input was the main factor having a significant, negative relationship to DOC/DON in soil water at all depths studied. This might reflect the effect of site conditions on both DOC/DON ratios and litter quantity. A comparison of DOC and DON concentrations and fluxes at two Norwegian sites (Birkenes and Hirkjølen) and five Finnish Level II plots (Tammela, Juupajoki, Uusikaarlepyy, Kivalo and Pallasjärvi) showed no obvious correlation between concentrations and site and stand properties such as growing season length, temperature, precipitation, stand age, or soil C or N. DOC concentrations in the O horizon could not be linked to N deposition. However, there were clear within-site seasonal trends, compatible with an effect of temperature on microbial activity.
Abstract
We investigated concentrations of dissolved organic carbon (DOC) in throughfall and soil solutions at 5, 15 and 40-cm depth in 16 Norway spruce and two Scots pine plots throughout Norway between 1996 and 2006. Average DOC concentrations ranged from 2.3 to 23.1 mg/l and from 1.1 to 53.5 mg/l in throughfall water and soil solutions, respectively. Concentrations of DOC in throughfall and soil waters varied seasonally at most plots with peaks in the growing season. By contrast to recently reported positive long-term trends in DOC concentrations in surface waters between 1986 and 2003, soil water data from 1996 to 2006 showed largely negative trends in DOC concentrations and no significant trends in throughfall. However, regression analysis for individual sites, particularly at 5- and 15-cm soil depths, showed that DOC concentrations in soil water were significantly and negatively related to non-marine sulphate (SO4) and chloride (Cl-). The lack of a long-term increase in DOC in soil water in the period May 1996-December 2006 may be due to the relatively small changes in the deposition of SO4 and Cl- in this period.
Abstract
We investigated concentrations of dissolved organic carbon (DOC) in throughfall and soil solutions at 5, 15 and 40 cm depth in 16 Norway spruce and 2 Scots pine plots throughout Norway between 1996 and 2006. Average DOC concentrations ranged from 2.3 mg/l to 23.1 mg/l and from 1.1 mg/l to 53.5 mg/l in throughfall water and soil solutions, respectively. Concentrations of DOC in throughfall and soil waters varied seasonally at most plots with peaks in the growing season. By contrast to recently reported positive long-term trends in DOC concentrations in surface waters between 1986 and 2003, soil water data from 1996 to 2006 showed largely negative trends in DOC concentrations and no significant trends in throughfall. However, regression analysis for individual sites, particularly at 5 and 15 cm soil depths, showed that DOC concentrations in soil water were significantly and negatively related to non-marine sulphate (SO4) and chloride (Cl-). The lack of a long-term increase in DOC in soil water in the period May 1996 – December, 2006 may be due to the relatively small changes in the deposition of SO4 and Cl- in this period.
Abstract
Dissolved organic nitrogen (DON) plays an important ecological role in forest ecosystems, and its concentration is related to that of dissolved organic carbon (DOC). We investigated DON concentrations and ratios of DOC to DON in throughfall and soil waters in 16 Norway spruce and two Scots pine forest stands sampled at weekly intervals between 1996 and 2006. The stands are all included in the ICP Forests Level II monitoring program and are located throughout Norway. DON concentrations were significantly and positively related to DOC concentrations in throughfall (r (2) = 0.72, p < 0.0001) and soil water at 5, 15, and 40 cm (r (2) = 0.86, 0.32, and 0.84 and p < 0.0001, 0.04, and < 0.0001, respectively). At most sites, the annual median DOC/DON ratio in throughfall ranged from 20.3 to 55.5, which is lower than values in soil water, which ranged from 24.5 to 81.3, gradually decreasing with soil depth. DON concentrations varied seasonally in throughfall at many plots and in soil water at 5-cm depth at one plot only, with higher values in the growing season, but there was no noticeable seasonality at greater depth. The ratios of DOC/DON in soil water were significantly positively related to the C/N ratio in soil at the same depth. Above-ground litter input was the main factor having a significant, negative relationship to DOC/DON in soil water at all depths studied. This might reflect the effect of site conditions on both DOC/DON ratios and litter quantity.
Abstract
The effects of genetically modified (GM) maize (Zea mays L.) expressing the Bacillus thuringiensis Berliner Cry1Fa2 protein (Bt) and phosphinothricin or glyphosate herbicide tolerance on soil chemistry (organic matter, N, P, K and pH), compared with non-GM controls, were assessed in field and pot experiments. In the field experiment, NH4+ was significantly higher in soil under the crop modified for herbicide tolerance compared to the control (mean values of 11 and 9.6 mg N/kg respectively) while P was significantly higher in soil under the control compared to under the GM crop (mean values of 6.9 and 6.4 dg P/kg, respectively). No significant differences were found as a result of growing Bt/herbicide tolerant maize. In the pot experiment, using soils from three sites (Gongzhuling, Dehui and Huadian), significant effects of using Bt maize instead of conventional maize were found for all three soils. In the Gongzhuling soil, P was significantly higher in soil under the control compared to under the GM crop (mean values of 4.8 and 4.0 dg P/kg, respectively). For the Dehui soil, the pH was significantly higher in soil under the control compared to under the GM crop (mean values for {H+} of 1.1 and 2.4 μM for the control and the GM crop respectively). In the Huadian soil, organic matter and total N were both higher in soil under the GM crop than under the control. For organic matter, the mean values were 3.0 and 2.9% for the GM crop and the control, respectively, while for total nitrogen the mean values were 2.02 and 1.96‰ for the GM crop and the control respectively. Our results indicate that growing GM crops instead of conventional crops may alter soil chemistry, but not greatly, and that effects will vary with both the specific genetic modification and the soil.
Authors
Nicholas Clarke Milan Gryndler Hans-Holger Liste Reiner Schroll Peter Schröder Miroslav MatuchaAbstract
The halogens, most importantly fluorine, chlorine, bromine, and iodine, occur in nature as ions and compounds, including organic compounds. Halogenated organic substances (haloorganics) were long considered purely anthropogenic products; however, they are in addition a commonly occurring and important part of natural ecosystems. Natural haloorganics are produced largely by living organisms, although abiotic production occurs as well. A survey is given of processes of formation, transport, and degradation of haloorganics in temperate and boreal forests, predominantly in Europe. More work is necessary in order to understand the environmental impact of haloorganics in temperate and boreal forest soils. This includes both further research, especially to understand the key processes of formation and degradation of halogenated compounds, and monitoring of the substances in question in forest ecosystems. It is also important to understand the effect of various forest management techniques on haloorganics, as management can be used to produce desired effects.
Authors
Aldo Marchetto Rosario Mosello Gabriele A. Tartari John Derome Kirsti Derome Nils König Nicholas Clarke Anna KowalskaAbstract
A Working Ring Test (WRT) was organised within the framework of the EU/Life+ FutMon Project (`Further Development and Implementation of an EU-level Forest Monitoring System`, LIFE07 ENV/D/000218), to evaluate the overall performance of the laboratories responsible for analysing atmospheric deposition and soil solution samples in European forests, and to verify improvements in the analytical quality resulting from the QA/QC work carried out in the laboratories which participated in previous WRTs organized in the framework of the UN/ECE ICP Forests Monitoring Programme. The WRT was carried out in accordance with International ISO and ILAG guide proficiency test both for sample preparation and numerical elaboration of the results. Four natural atmospheric deposition and soil solution samples and 4 synthetic solutions were distributed to 44 laboratories for analysis using their routine methods for the following variables: pH, conductivity, calcium, magnesium, sodium, potassium, ammonium, sulphate, nitrate, chloride, total alkalinity, total dissolved nitrogen (TDN), dissolved organic carbon (DOC). Two tolerable limits were defined for each variable on the basis of the measured value, the results of previous WRTs, a comparison with the Data Quality Objectives of other international networks, and the importance of the variable in deposition and soil solution monitoring. In the ring test 16% of the results from all the laboratories did not fall within the tolerable limits. This enabled us to identify those variables and laboratories for which improvements in analytical performance are required. The results of the exercise clearly show that the use of data check procedures, as described in the ICP Forests manual for sampling and analysis of atmospheric deposition, makes it possible to detect the presence of inaccurate or outlying results, and would therefore greatly improve the overall performance of the laboratories. Some of the analytical methods used by individual laboratories were found to be unsuitable for the samples included in this WRT, and therefore also for the routine analysis of atmospheric deposition and soil solution samples in European forests. These methods included outdated methods, such as turbidimetry or nephelometry for the determination of sulphate, silver nitrate titration and ion selective electrode for chloride, Kjeldahl digestion for the determination of ammonium and organic nitrogen, and colorimetric titrations for alkalinity. A detailed discussion of the determination of total alkalinity is also given in the report because this variable was associated with the most analytical problems.
Authors
Holger Lange Nicholas Clarke O. Janne Kjønaas Wenche Aas Kjell Andreassen Isabella Børja Harald Bratli Susanne Eich-Greatorex Toril Drabløs Eldhuset Kjersti Holt Hansen Tonje Ingeborg Økland Ingvald Røsberg Trine Aulstad Sogn Volkmar TimmermannAbstract
No abstract has been registered
Authors
Nicholas Clarke O. Janne Kjønaas Wenche Aas Kjell Andreassen Isabella Børja Harald Bratli Susanne Eich-Greatorex Toril Drabløs Eldhuset Kjersti Holt Hanssen Holger Lange Tonje Økland Ingvald Røsberg Trine Aulstad Sogn Volkmar TimmermannAbstract
In Norway, it is planned to double the stationary use of bioenergy from all sources by up to 14 TWh before 2020, with much of this increase coming from forest resources, including residues like branches and tops (which are not much used today) being removed after tree harvest. This removal will reduce the supply of nutrients and organic matter to the forest soil, and may in the longer term increase the risk for future nutrient imbalance, reduced forest production, and changes in biodiversity and ground vegetation species composition. However, field experiments have found contrasting results (e.g. Johnson and Curtis 2001; Olsson et al. 1996). Soil effects of increased biomass removal will be closely related to soil organic matter (SOM) dynamics, litter quality, and turnover rates. The SOM pool is derived from a balance between above- and below-ground input of plant material and decomposition of both plants and SOM. Harvest intensity may affect the decomposition of existing SOM as well as the build-up of new SOM from litter and forest residues, by changing factors like soil temperature and moisture as well as amount and type of litter input. Changes in input of litter with different nutrient concentrations and decomposition patterns along with changes in SOM decomposition will affect the total storage of carbon, nitrogen and other vital nutrients in the soil. To quantify how different harvesting regimes lead to different C addition to soil, and to determine which factors have the greatest effect on decomposition of SOM under different environmental conditions, two Norway spruce forest systems will be investigated in the context of a research project starting in 2008/2009, one in eastern and one in western Norway, representing different climatic and landscape types. At each location, two treatment regimes will be tested: Conventional harvesting, with residues left on-site (CH) Aboveground whole-tree harvest, with branches, needles, and tops removed (WTH). Input of different forest residues will be quantified post harvest. Soil water at 30 cm soil depth will be analysed for nutrients and element fluxes will be estimated to provide information about nutrient leaching. Soil respiration will be measured, along with lab decomposition studies under different temperature and moisture regimes. Long term in situ decomposition studies will be carried out in the WTH plots using three different tree compartments (needles, coarse twigs, fine roots) decomposing in litter bags, in order to determine their limit value. The structure of the fungal community will be determined by soil core sampling and use of molecular techniques allowing qualitative and quantitative estimation. Understorey vegetation will be sampled to determine the biomass, and the frequency of all vascular plants, bryophytes and lichens will be estimated. After harvesting, replanting will be carried out. Seedling survival, causes of mortality and potential damage, growth, and needle nutrients will be monitored. Results from these studies will be used to identify key processes explaining trends observed in two series of ongoing long-term whole-tree thinning trials. We shall combine knowledge obtained using field experiments with results of modelling and data from the Norwegian Monitoring Programme for Forest Damage and National Forest Inventory. This will help us to predict and map the ecologically most suitable areas for increased harvesting of branches and tops on a regional scale based on current knowledge, and to identify uncertainties and additional knowledge needed to improve current predictions.
Authors
Martin Lorenz Richard Fischer Georg Becher Volker Mues Oliver Granke Tatyana Braslavskaya Alexey Bobrinsky Natalia Lukina Nicholas Clarke Zora Lachmanová Claus SchimmingAbstract
Of the 41 countries participating in ICP Forests, 27 countries reported national results of crown condition surveys in the year 2008 for 210 964 trees on 14 786 plots. The transnational result on the European-wide scale relied on 111 560 trees on 5 002 plots of the 16 x 16 km grid in 25 out of 35 participating countries. Mean defoliation of all sample trees of the transnational survey was 20.2%. Of the main species, Quercus robur and Q. petraea had by far the highest mean defoliation (24.9%), followed by Fagus sylvatica (19.4%), Picea abies (19.3%) and Pinus sylvestris (18.2%). These figures are not comparable to those of previous reports because of fluctuations in the plot sample, mainly due to changes in the participation of countries. Therefore, the long-term development of defoliation was calculated from the monitoring results of those countries which have been submitting data since 1990 every year without interruption. In the period of observation the species group Quercus ilex and Quercus rotundifolia shows the severest increase in defoliation, with 10.3% in 1990 and 21.2% in 2008. A similar increase in defoliation, namely from 11.1% to 20.4%, was experienced by Pinus pinaster. Defoliation of these Mediterranean species is largely attributed to several summer drought events. Defoliation of Fagus sylvatica increased from 17.9% to 19.7%. In contrast, Picea abies, Quercus robur and Quercus petraea and in particular Pinus sylvestris recuperated from peaks in defoliation in the mid 1990s. The spatial and temporal variation of bulk deposition and throughfall of sulphate, nitrate, ammonium, calcium, sodium and chlorine was analysed as a basis of ongoing and future studies. Between 174 and 302 intensive monitoring plots were involved in the study. Mean deposition of the years 2004 - 2006 shows spatial patterns reflecting partly regional emission situations. The temporal variation was calculated for the period 2001 - 2006. Sulphur throughfall decreased from 6.0 kg ha-1 yr-1 in 2001 to 4.5 kg ha-1 yr-1 in 2006. Bulk deposition of sulphur shows a similar decrease at a lower level, namely from 4.9 kg ha-1 yr-1 in 2001 to 3.6 kg ha-1 yr-1 in 2006 (corrected for sea salt input). Nitrogen deposition shows a less pronounced rate of decrease.
Authors
Aldo Marchetto Rosario Mosello Gabriele Tartari O Tornimbeni J Derome Kisti Derome Pia Sorsa Nils Konig Nicholas Clarke Erwin Ulrich Anna KowalskaAbstract
No abstract has been registered
Abstract
Growth of Norway spruce (Picea abies) trees and nitrogen deposition were analysed at about 500 forest plots throughout Norway in six fiveyear periods from 1977 to 2006. Growth was calculated from five repeated calliper measurements of all trees during this period and using treering series from increment cores of a subsample of trees. From the growth data a `relative growth` variable was extracted, being the deviation in % between observed and expected growth rates. The expected growth was estimated from growth models based on site productivity, age and stand density at each plot. The plots were categorized into four age classes. The nitrogen deposition was estimated for each plot for the same five year periods by geographical interpolation of deposition observations at monitoring stations made by the Norwegian Institute for Air Research. Nitrogen deposition from 1977 to 2006 ranged from 1 to 24 kg/ha/yr at the study plots, with about 15 kg/ha/yr in the southernmost region and 3 kg/ha/yr in the northern region of Norway. For the entire 30year period we found a long term relationship between growth and nitrogen deposition, corresponding to a forest growth increase of 0.7% per kg total nitrogen deposition per hectare and year (r2 = 0.13). This is in line with studies carried out on other data sets and for shorter time periods. This apparent fertilizing effect was most pronounced for the youngest forest, while the effect was weak for the oldest forest. The growth increase was observed in the southernmost part of Norway, the region with the highest nitrogen deposition. However, the relationship between nitrogen deposition and growth varied considerably between the time periods. In two of the periods the relationship was slightly negative: these periods corresponded well with summer droughts occurring in the southernmost part of Norway. Drought, as well as other climatic factors, will influence the shortterm variations in forest growth and may obscure the fertilizing effect of nitrogen deposition in some periods. In conclusion, nitrogen deposition has most likely increased growth in Norway spruce in southern Norway. However, our study also shows that inferences from such correlative studies should be drawn with care if the growth period is shorter than 10–15 years because climatic factors produce temporal variations in the relationship between nitrogen deposition and forest growth.
Authors
Nicholas Clarke Květoslava Fuksová Milan Gryndler Zora Lachmanová Hans-Holger Liste Jana Rohlenova Reiner Schroll Peter Schröder Miroslav MatuchaAbstract
No abstract has been registered
Authors
Karsten Raulund-Rasmussen Inge Stupak Nicholas Clarke Ingeborg Callesen Helja-Sisko Helmisaari Erik Karltun Iveta Varnagiryte-KabasinskieneAbstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
No abstract has been registered