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- Iwald, Johan, et al.
(författare)
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Acidifying effect of removal of tree stumps and logging residues as compared to atmospheric deposition
- 2013
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 290, s. 49-58
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Tidskriftsartikel (refereegranskat)abstract
- Harvesting of stumps and logging residues for bioenergy can be expected to increase in the future. An increased biomass export from the forest will increase the biological acidification, measured as net cation (cations-anions) export. The aim of this study is to estimate the acidifying effect that various levels of harvesting of tree stumps and logging residues will have in Sweden, and compare this with the acidification currently caused by acid deposition. Estimations of yearly logging of Scots pine (Pinus sylvestris L), Norway spruce (Picea abies (L) Karst.) and birch (Betula spp.) on county-level were made based on scenario data from forestry consequence analyses and data from the Swedish National Forest Inventory. Data of cation and anion contents in tree parts were used to calculate the net cation extraction per area unit resulting from harvesting of stumps, stem-wood and logging residues, respectively. County-level data were merged into data for three different regions representing a gradient in deposition and climate.Results indicate that harvesting of stumps constitutes 13-24% of total (stumps + stem-wood + logging residues) excess cation extraction, depending on harvest intensity and tree species. Harvesting of logging residues constitutes 27-45% of total net cation extraction. The higher acidifying effect of logging residues can be explained by the higher contents of base cations in needles and branches compared to stem-wood. In a comparison between total net cation extraction by tree harvesting and maximum levels of current acid deposition the acidifying effect of pine harvesting is 57-108% of that of acid deposition, the acidifying effect of spruce harvesting is 114-263% while the acidifying effect of birch harvesting is 60-171%. Concerning the amount of acid input to the soil per unit heating value as biofuel, stump harvesting generates 12-27 eq H+ MWh(-1) while logging residue harvesting generates 39-66 eq H+ MWh(-1).Stump harvesting generates a higher heating value per area unit than logging residue harvesting and results in a lower acid input to the soil per unit heating value generated. Thus, from a strict nutrient balance and acidification perspective stump harvesting is a better alternative than harvesting of logging residues. (C) 2012 Elsevier B.V. All rights reserved.
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| 4. |
- Iwald, Johan, et al.
(författare)
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Effekter på mark av 50 års försurningsbelastning från atmosfärisk deposition och katjonupptag i biomassa : en analys av data från Riksskogstaxeringen och Markinventeringen
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Den atmosfäriska depositionen av försurande ämnen har i sydvästra Sverige minskat till mindre än en femtedel av vad den var i början av 1990-talet. En möjlig förklaring till den trots detta, långsamma återhämtningen från försurningen av mark och vatten i skogslandskapet, är att den biologiska försurningen har ökat på grund av en ökad tillväxt som möjliggjort en kontinuerlig ökning av både stående biomassa och skörd av skogsråvara. Dessutom har ett ökat uttag av GROT för förbränning ytterligare bidragit till den biologiska försurningsbelastningen. I rapporten kvantifierar och jämför vi förändringarna i försurningsbelastning från deposition, skogstillväxt och avverkning från 1950/60 fram till idag och relaterar denna till skogsmarkens försurningsstatus och förråden av växttillgängliga baskatjoner i mark och biomassa. Rapporten baserar sig på data från Riksskogstaxeringen, Markinventeringen, EMEP och SMHI samt information från olika vetenskapliga artiklar. De stora förändringarna i försurningsbelastning sedan 1950-talet har skett genom förändringar i depositionen, först genom en stor uppgång fram till slutet av 1980-talet och sedan genom en ännu snabbare nedgång under 1990- och 2000-talen. Skogsbrukets bidrag till försurningsbelastningen har ökat något under perioden genom ökad bortförsel av träddelar vid avverkning och ökat upptag i stående biomassa, men ökningen är bara signifikant i den sydöstra regionen. Ökningen är relativt måttlig och förändringarna är små i förhållande till de förändringar som har skett i total försurningsbelastning genom förändringar i depositionsbelastning. Det ökade uttaget av GROT har ökat försurningsbelastningen, främst i sydvästra och sydöstra Sverige där uttaget är störst, men är totalt sett en mindre del av den skogsproduktionsrelaterade försurningsbelastningen i ett brukat skogslandskap. Det finns inte någon tydlig geografisk trend i markens baskatjonförråd relaterat till den totala försurningsbelastningen. Förrådet av utbytbara baskatjoner i marken varierar mer med markens och modermaterialets geokemiska egenskaper än med försurningsbelastningen. Resultaten från den här studien representerar det faktiska GROT-uttaget som skett i skogslandskapet på länsnivå, vilket innebär att slutsatserna från studien inte behöver återspegla effekterna på beståndsnivå där det fortfarande kan vara problem med näringstillgången och behov av kompensation i form av t.ex. askåterföring.
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| 7. |
- Karltun, Erik, et al.
(författare)
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Forest biomass accumulation is an important source of acidity to forest soils: Data from Swedish inventories of forests and soils 1955 to 2010
- 2021
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Ingår i: AMBIO: A Journal of the Human Environment. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 51, s. 199-208
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Tidskriftsartikel (refereegranskat)abstract
- The input of acidity to Swedish forest soils through forestry between 1955 and 2010 is compared with the acid input from atmospheric deposition. Depending on region, input of acidity from forestry was the minor part (25-45%) of the study period's accumulated acid input but is now the dominating source (140-270 mol(c) ha(-1) year(-1)). The net uptake of cations due to the increase in standing forest biomass, ranged between 35 and 45% of the forestry related input of acidity while whole-tree harvesting, introduced in the late 1990s, contributed only marginally (< 2%). The geographical gradient in acid input is reflected in the proportion of acidified soils in Sweden but edaphic properties contribute to variations in acidification sensitivity. It is important to consider the acid input due to increases in standing forest biomass in acidification assessments since it is long-term and quantitatively important.
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| 8. |
- Akselsson, Cecilia, et al.
(författare)
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Weathering rates in Swedish forest soils
- 2019
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Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 16:22, s. 4429-4450
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Forskningsöversikt (refereegranskat)abstract
- Soil and water acidification was internationally recognised as a severe environmental problem in the late 1960s. The interest in establishing “critical loads” led to a peak in weathering research in the 1980s and 1990s, since base cation weathering is the long-term counterbalance to acidification pressure. Assessments of weathering rates and associated uncertainties have recently become an area of renewed research interest, this time due to demand for forest residues to provide renewable bioenergy. Increased demand for forest fuels increases the risk of depleting the soils of base cations produced in situ by weathering. This is the background to the research programme Quantifying Weathering Rates for Sustainable Forestry (QWARTS), which ran from 2012 to 2019. The programme involved research groups working at different scales, from laboratory experiments to modelling. The aims of this study were to (1) investigate the variation in published weathering rates of base cations from different approaches in Sweden, with consideration of the key uncertainties for each method; (2) assess the robustness of the results in relation to sustainable forestry; and (3) discuss the results in relation to new insights from the QWARTS programme and propose ways to further reduce uncertainties. In the study we found that the variation in estimated weathering rates at single-site level was large, but still most sites could be placed reliably in broader classes of weathering rates. At the regional level, the results from the different approaches were in general agreement. Comparisons with base cation losses after stem-only and whole-tree harvesting showed sites where whole-tree harvesting was clearly not sustainable and other sites where variation in weathering rates from different approaches obscured the overall balance. Clear imbalances appeared mainly after whole-tree harvesting in spruce forests in southern and central Sweden. Based on the research findings in the QWARTS programme, it was concluded that the PROFILE/ForSAFE family of models provides the most important fundamental understanding of the contribution of weathering to long-term availability of base cations to support forest growth. However, these approaches should be continually assessed against other approaches. Uncertainties in the model approaches can be further reduced, mainly by finding ways to reduce uncertainties in input data on soil texture and associated hydrological parameters but also by developing the models, e.g. to better represent biological feedbacks under the influence of climate change.
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| 9. |
- Berg, Björn, et al.
(författare)
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Manganese in the litter fall-forest floor continuum of boreal and temperate pine and spruce forest ecosystems : a review
- 2015
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 358, s. 248-260
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Forskningsöversikt (refereegranskat)abstract
- We have reviewed the literature on the role of manganese (Mn) in the litter fall-to-humus subsystem. Available data gives a focus on North European coniferous forests. Manganese concentrations in pine (Pinus spp.) foliar litter are highly variable both spatially and temporally within the same litter species and for the genus Pinus we found a range from 0.03 to 3.7mgg-1. Concentrations were related negatively to site mean annual temperature (MAT) and annual actual evapotranspiration (AET) for pine species litter but not for that of Norway spruce (Picea abies) as a single species. Combined data for several species showed a highly significant relationship to MAT.Manganese peroxidase is an Mn-dependent enzyme, found in white-rot fungi, essential for the degradation of lignin and ligninlike compounds. The decomposition rates of lignified litter tissue (late phase) is positively related to the litter’s Mn concentration. Further, the Mn concentration is positively related to the limit value for decomposition - the higher the Mn concentration the smaller the stable litter fraction. Manganese release from decomposing litter appears at least in part to be species related. Thus was release from pine needle litter significantly faster (p<. 0.001) than that from the Mn-richer litter of Norway spruce. Over Northern Europe concentrations of total Mn in mor humus as well as extractable Mn in the mineral soil increase with decreasing MAT and over a climatic gradient the Mn concentrations in Norway spruce mor increase more with decreasing MAT than in a gradient with Scots pine. Higher Mn concentrations in humus appear to decrease its stability and result in a higher release of carbon dioxide (CO2) and dissolved organic carbon (DOC). We conclude that this may explain (i) the lower amount of carbon (C) in mor layers under Norway spruce as compared to Scots pine as well as the higher amount of C in mineral soil under spruce. The increase in nitrogen (N) concentration in humus, following N fertilization resulted in a decrease in that of Mn. We have found four cases - empirical - with negative interaction between Mn and N; (i) in pine foliar litter fall concentrations of Mn decrease with site MAT whereas those of N increase, (ii) in decomposing late-stage litter with N retarding and Mn stimulating decomposition, (iii) for the stable phase, limit values are related negatively to N and positively to Mn, and (iv) Mn concentrations in humus decrease with MAT whereas those of N increase.
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| 10. |
- Casetou, Sophie, et al.
(författare)
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Comparison of measured (XRPD) and modeled (A2M) soil mineralogies : A study of some Swedish forest soils in the context of weathering rate predictions
- 2018
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Ingår i: Geoderma. - : Elsevier BV. - 0016-7061 .- 1872-6259. ; 310, s. 77-88
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Tidskriftsartikel (refereegranskat)abstract
- Quantitative soil mineralogy has been identified as a key factor influencing PROFILE weathering estimates, and is often calculated with normative methods, such as the “Analysis to Mineralogy” (‘A2M’) model. In Sweden and other countries, there is a large request for accurate base cation weathering estimates in order to establish how sustainable harvest of biomass should be performed in the future. However, there is a lack of knowledge around the accuracy of the arithmetic mean output of A2M estimates, the most common A2M solution used in weathering studies. To our knowledge, a thorough investigation of how A2M input data affect the arithmetic mean output (center of gravity of the A2M solution space) is missing. In this study, the indirect geochemical normative method (A2M) was compared with a direct x-ray powder diffraction method (XRPD) to quantify soil mineralogy at two sites and 8 soil profiles, at a 10 cm depth interval. We explored the hypothesis that normative calculations performed with A2M produce an output in closer agreement with the mineralogy obtained from XRPD, if site specific mineralogical input data are used rather than regional data. Site-specific mineralogical input data consisted of mineral stoichiometry data measured by electron microprobe analysis (EMPA) and mineral identity determined by XRPD, whereas regional mineral input data were based on previously reported data on mineral stoichiometry and mineral identity, derived from three geological regions in Sweden. The results from this comparison showed that the site-specific approach yielded relatively low average biases and root mean square errors (RMSE) for most minerals, with the exception of quartz (Average bias of − 4.8 wt%, RMSE of 5.3 wt%) at the Asa site. The regional approach yielded deviating results for K-feldspar and dioctahedral mica, with high average biases and RMSE for dioctahedral mica (Asa: 7.8 wt%, 9.0 wt%; Flakaliden: 12.8 wt%, 15.5 wt%) and for K-feldspar (Asa: − 5.2 wt%, 6.1 wt%; Flakaliden: − 5.6 wt%, 6.7 wt%). The results from this study were supported by a close agreement between measured geochemistry and normalized geochemistry derived from a back calculation of the XRPD mineralogy (i.e. mineral budgeting). In conclusion, our findings suggest that A2M results in combination with site-specific mineralogical input data are improved independent of study site and soil profile. However, for future weathering studies it might be beneficial to find constraints of how to select a solution from the entire A2M solution space which is in better agreement with the XRPD mineralogy.
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