| 1. |
- Fagerberg, Nils, 1972-, et al.
(författare)
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Evaluation of individual-tree growth models for Picea abies based on a case study of an uneven-sized stand in southern Sweden
- 2022
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Ingår i: Scandinavian Journal of Forest Research. - : Taylor & Francis Group. - 0282-7581 .- 1651-1891. ; 37:1, s. 45-58
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Tidskriftsartikel (refereegranskat)abstract
- To develop recommendations for tree selection in Continuous Cover Forestry (CCF), access to valid tools for simulating growth at individual tree-level is necessary. To assist efforts to develop such tools, in this study, long-term observation data from two uneven-sized Norway spruce plots in southern Sweden are used to evaluate old and new individual-tree growth models (two established Swedish models, two new preliminary models and included as a reference, a Finnish model). The plots' historical management records and site conditions are the same, but their last thinning treatment differs. Observed diameter increment at tree-level is investigated in relation to treatment. Individual tree growth residuals of tested models are evaluated in relation to tree diameter, treatment, projection length and sensitivity to the predictor mean stand age. Furthermore, the relations between displayed residuals and basal area local competition are analysed. The analyses indicate that active thinning made annual diameter increment independent of tree diameter above a threshold level, while the absence of thinning supported a concave relationship. All tested models displayed a significant linear bias leading to overestimation of small trees' growth and increasing underestimations of larger trees' growth with tree diameter. All distance-independent models displayed residual trends related to local competition.
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| 2. |
- Haus, Sylvia
(författare)
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Climate impact of the sustainable use of forest biomass in energy and material system : a life cycle perspective
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Human society releases greenhouse gas emissions to the atmosphere while providing housing, heat, mobility and industrial production. Man-made greenhouse gas emissions are the main causes of climate change, coming mainly from burning fossil fuels and land-use changes. Sustainably managed forests play an important role in climate change mitigation with the prospect of sustainably providing essential materials and services as part of a low-carbon economy, both through the substitution of fossil-intensive fuels and material and through their potential to capture and store carbon in the long-term perspective.The overall aim of this thesis was to develop a methodology under a life cycle perspective to assess the climate impact of the sustainable use of forest biomass in bioenergy and material systems. To perform this kind of analysis a methodological framework is needed to accurately compare the different biological and technological systems with the aim to minimize the net carbon dioxide emissions to the atmosphere and hence the climate impact. In such a comparison, the complete energy supply chains from natural resources to energy end-use services has to be considered and are defined as the system boundaries.The results show that increasing biomass production through more intensive forest management or the usage of more productive tree species combined with substitution of non-wood products and fuels can significantly reduce global warming. The biggest single factor causing radiative forcing reduction was using timber to produce wood material to replace energy-intensive construction materials such as concrete and steel. Another very significant factor was replacing fossil fuels with forest residues from forest thinning, harvest, wood processing, and post-use wood products. The fossil fuel that was replaced by forest biomass affected the reductions in greenhouse gas emissions, with carbon-intensive coal being most beneficial to replace. Over the long term, an active and sustainable management of forests, including their use as a source for wood products and bioenergy allows the greatest potential for reducing greenhouse gas emissions.
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| 3. |
- Lundmark, Tomas, et al.
(författare)
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Carbon balance in production forestry in relation to rotation length
- 2018
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Ingår i: Canadian Journal of Forest Research. - : Canadian Science Publishing. - 0045-5067 .- 1208-6037. ; 48:6, s. 672-678
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Tidskriftsartikel (refereegranskat)abstract
- The choice of a rotation length is an integral part of even-aged forest management regimes. In this study, we have simulated stand development and carbon pools in four even-aged stands representing the two most common tree species in Fennoscandia, Norway spruce (Picea abies) and Scots pine (Pinus sylvestris), growing on high and low productive sites. We hypothesized that increased rotation lengths (+10, +20 and +30 years) in comparison with today’s practice would increase forests’ average carbon stock during a rotation cycle, but decrease the average yield. The results showed that for spruce a moderate increase in rotation length (+10 years) increased both average standing carbon stock and average yield. For the longer alternatives (+20 and +30 years) for spruce and for all pine alternatives prolonging rotation lengths resulted in increased average standing carbon stocks but decreased average yield resulting in decreased carbon storage in forest products and decreased substitution effects. Decreasing the rotation lengths (-10 years) always resulted in both decreased average standing carbon stocks and decreased yields. We conclude that a moderate increase of rotation lengths may slightly increase forests’ climate benefits for spruce sites but for all other alternatives there was a trade-off between the temporary gain of increasing carbon stocks and the permanent loss in productivity and consequently substitution potential.
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| 4. |
- Lundmark, Tomas, et al.
(författare)
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Comparison of carbon balances between continuous-cover and clear-cut forestry in Sweden
- 2016
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Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 45:supplement 2, s. S203-S213
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Tidskriftsartikel (refereegranskat)abstract
- Continuous-cover forestry (CCF) has been recognized for the production of multiple ecosystem services, and is seen as an alternative to clear-cut forestry (CF). Despite the increasing interest, it is still not well described how CCF would affect the carbon balance and the resulting climate benefit from the forest in relation to CF. This study compares carbon balances of CF and CCF, applied as two alternative land-use strategies for a heterogeneous Norway spruce (Picea abies) stand. We use a set of models to analyze the long-term effects of different forest management and wood use strategies in Sweden on carbon dioxide emissions and carbon stock changes. The results show that biomass growth and yield is more important than the choice of silvicultural system per se. When comparing CF and CCF assuming similar growth, extraction and product use, only minor differences in long-term climate benefit were found between the two principally different silvicultural systems.
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| 5. |
- Lundmark, Tomas, et al.
(författare)
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Potential Roles of Swedish Forestry in the Context of Climate Change Mitigation
- 2014
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Ingår i: Forests. - Basel, Switzerland : MDPI AG. - 1999-4907. ; 5:4, s. 557-578
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Tidskriftsartikel (refereegranskat)abstract
- In Sweden, where forests cover more than 60% of the land area, silviculture and the use of forest products by industry and society play crucial roles in the national carbon balance. A scientific challenge is to understand how different forest management and wood use strategies can best contribute to climate change mitigation benefits. This study uses a set of models to analyze the effects of different forest management and wood use strategies in Sweden on carbon dioxide emissions and removals through 2105. If the present Swedish forest use strategy is continued, the long-term climate change mitigation benefit will correspond to more than 60 million tons of avoided or reduced emissions of carbon dioxide annually, compared to a scenario with similar consumption patterns in society but where non-renewable products are used instead of forest-based products. On average about 470 kg of carbon dioxide emissions are avoided for each cubic meter of biomass harvested, after accounting for carbon stock changes, substitution effects and all emissions related to forest management and industrial processes. Due to Sweden’s large export share of forest-based products, the climate change mitigation effect of Swedish forestry is larger abroad than within the country. The study also shows that silvicultural methods to increase forest biomass production can further reduce net carbon dioxide emissions by an additional 40 million tons of per year. Forestry’s contribution to climate change mitigation could be significantly increased if management of the boreal forest were oriented towards increased biomass production and if more wood were used to substitute fossil fuels and energy-intensive materials.
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| 6. |
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| 7. |
- Poudel, Bishnu Chandra, 1976-
(författare)
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Carbon Balance Implications of Forest Biomass Production Potential
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Forests in boreal and temperate forest-ecosystems have importance for carbonbalance since they sequester large amount of atmospheric carbon by uptake ofcarbon-dioxide during photosynthesis, and transfer and store carbon in the forestecosystem. Forest material can be used for bio-fuel purposes and substitute fossilfuels, and supply wood products, which can replace carbon-and-energy-intensivematerials. Therefore it is vital to consider the role of forests regarding today´s aimto mitigate climate change. This thesis assess (i) how climate change affects futureforest carbon balance, (ii) the importance of different strategies for forestmanagement systems, and biomass production for the carbon balance, (iii) how theuse of forest production affect the total carbon balance in a lifecycle perspective,and (iv) how the Swedish carbon balance is affected from the standpoint of boththe actual use of forest raw material within Sweden and what Swedish forestryexports. The analysis was made mainly in a long-term perspective (60-300 years) toillustrate the importance of temporal and also the spatial perspective, as theanalysis includes stand level, landscape level, and national level.In this thesis, forestry was considered a system. All activities, from forestregeneration to end use of forest products, were entities of this system. In theevaluation, made from a systems perspective, we used life-cycle analysis toestimate carbon stock in different system flows. Different forest managementsystems and forest production were integrated in the analyses. Different forestmanagement scenarios were designed for the Swedish forest management incombination with the effect of future climate change; (i) intensive forest practiceaiming at increased growth, (ii) increased forest set-aside areas, changes in forestmanagement systems for biomass production, and (iii) how the use of forestproducts affect the total carbon balance (construction material, bioenergy and otherdomestic use).The results showed that future climate changes and intensive forest managementwith increased production could increase the biomass production and the potentialuse of forest raw material. This has a positive effect on carbon stock change in theforest biomass, litter production and below ground carbon stock and help reducingcarbon-dioxide emissions. Increased forest set-aside areas can increase the shorttermcarbon stock in forest ecosystems, but will reduce the total long-term carbonbalance. The net carbon balance for clear-cut forestry did not differ significantlyfrom continuous-cover forestry, but was rather a question of level of growth. Mostimportant, in the long term, was according to our analysis, how forest raw materialis used. Present Swedish forestry and use of forest raw material, both withinSweden and abroad, reduce carbon-dioxide emissions and mitigate climate change.The positive effect for the total carbon balance and climate benefit mostly takeplace abroad, due to the Swedish high level of export of wood products and thehigher substitution effects achieved outside Swedish borders. One strategy is toincrease production, harvest and use Swedish forest raw material to replace morecarbon intensive material, which can contribute to significant emission reduction.Carbon-dioxide mitigation, as a result of present Swedish forestry, was shown tobe almost of the same level as the total yearly emission of greenhouse gases. Thetotal carbon benefit would increase if the biomass production and felling increasedand if Swedish wood products replaced carbon intensive materials.This thesis shows also that, by changing forest management, increase thegrowth and the use of forest raw material and export of forest material we cancontribute to even larger climate benefits. In a long-term perspective, thesubstitution effects and replacement of carbon-and energy-intensive materials areof greater significance than carbon storage effects in forests. A more productionoriented forestry needs to make balances and increase the prerequisite forbiological diversity, improve recreation possibilities, and protect sensitive landareas and watersheds.Climate benefits, from Swedish forestry, are highly dependent on policydecision-making and how that can steer the direction for the Swedish forestry.
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| 8. |
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| 9. |
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| 10. |
- Poudel, Bishnu Chandra, 1976-
(författare)
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Forest Biomass Production Potential and its Implications for Carbon Balance
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- An integrated methodological approach is used to analyse the forestbiomass production potential in the Middle Norrland region of Sweden, and itsuse to reduce carbon emissions. Forest biomass production, forest management,biomass harvest, and forest product use are analyzed in a system perspectiveconsidering the entire resource flow chains. The system-wide carbon flows as wellas avoided carbon emissions are quantified for the activities of forest biomassproduction, harvest, use and substitution of non-biomass materials and fossil fuels.Five different forest management scenarios and two biomass use alternatives aredeveloped and used in the analysis. The analysis is divided into four main parts. Inthe first part, plant biomass production is estimated using principles of plantphysiologicalprocesses and soil-water dynamics. Biomass production is comparedunder different forest management scenarios, some of which include the expectedeffects of climate change based on IPCC B2 scenario. In the second part, forestharvest potentials are estimated based on plant biomass production data andSwedish national forest inventory data for different forest managementalternatives. In the third part, soil carbon stock changes are estimated for differentlitter input levels from standing biomass and forest residues left in the forestduring the harvest operations. The fourth and final part is the estimation of carbonemissions reduction due to the substitution of fossil fuels and carbon-intensivematerials by the use of forest biomass. Forest operational activities such asregeneration, pre-commercial thinning, commercial thinning, fertilisation, andharvesting are included in the analysis. The total carbon balance is calculated bysumming up the carbon stock changes in the standing biomass, carbon stockchanges in the forest soil, forest product carbon stock changes, and the substitutioneffects. Fossil carbon emissions from forest operational activities are calculated anddeducted to calculate the net total carbon balance.The results show that the climate change effect most likely will increaseforest biomass production over the next 100 years compared to a situation withunchanged climate. As an effect of increased biomass production, there is apossibility to increase the harvest of usable biomass. The annual forest biomassproduction and harvest can be further increased by the application of moreintensive forestry practices compared to practices currently in use. Deciduous treesare likely to increase their biomass production because of climate change effectswhereas spruce biomass is likely to increase because of implementation ofintensive forestry practices.Intensive forestry practices such as application of pre-commercialthinning, balanced fertilisation, and introduction of fast growing species to replaceslow growing pine stands can increase the standing biomass carbon stock. Soilcarbon stock increase is higher when only stem-wood biomass is used, comparedto whole-tree biomass use. The increase of carbon stocks in wood productsdepends largely on the magnitude of harvest and the use of the harvested biomass.The biomass substitution benefits are the largest contributor to the total carbonbalance, particularly for the intensive forest management scenario when wholetreebiomass is used and substitutes coal fuel and non-wood constructionmaterials. The results show that the climate change effect could provide up to 104Tg carbon emissions reduction, and intensive forestry practices may furtherprovide up to 132 Tg carbon emissions reduction during the next 100 years in thearea studied.This study shows that production forestry can be managed to balancebiomass growth and harvest in the long run, so that the forest will maintain itscapacity to increase standing biomass carbon and provide continuous harvests.Increasing standing biomass in Swedish managed forest may not be the mosteffective strategy to mitigate climate change. Storing wood products in buildingmaterials delays the carbon emissions into the atmosphere, and the wood materialin the buildings can be used as biofuel at the end of a building life-cycle tosubstitute fossil fuels.These findings show that the forest biomass production potential in thestudied area increases with climate change and with the application of intensiveforestry practices. Intensive forestry practice has the potential for continuousincreased biomass production which, if used to substitute fossil fuels andmaterials, could contribute significantly to net carbon emissions reductions andhelp mitigate climate change.
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