In spite of the large number of research works on carbon capture and sequestration (CCS), the migration and behaviour of CO2 in the subsurface (i. e. strata below the earth's surface) still needs further understanding and investigations with the aim of encouraging the governmental policy makers to adopt CCS technology as one of the most viable means to tackle the global warming threats. In this research work, a series of numerical simulations has been carried out using STOMP-CO2 simulation code to determine the flow behaviour and ultimate fate of the injected supercritical carbon dioxide (scCO2) into saline aquifers in medium terms of storage (i. e. few thousand years). The characteristics of the employed simulator, including the mathematical algorithm, governing equations, equations of states and phase equilibria calculations are explained in details.

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No. of bitstreams: 1 freiberger_mb_dr_bot.pdf: 1663017 bytes, checksum: 79b257695de46e620dc8065c2ad772ce (MD5) Previous issue date: 2016-02-22 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O estudo teve por principal objetivo avaliar o estoque de carbono (C), as alterações na quantidade de C microbiano, a qualidade da matéria orgânica (MO) e a emissão de CO2 em decorrência de aplicações de lodos de esgoto em área sob semeadura direta. A área experimental, que apresenta Latossolo Vermelho de textura argilosa e está localizada em Botucatu, SP, tem sido conduzida com os mesmos tratamentos desde 2002. Os resultados constantes no presente estudo, entretanto, foram obtidos no período de outubro de 2012 a outubro de 2014. O delineamento experimental utilizado foi o de blocos ao acaso em esquema fatorial 2 x 4, com quatro repetições. Os tratamentos correspondem à aplicação bienal de dois resíduos (lodo biodigerido – LB e lodo centrifugado – LC) em quatro doses: 0, 2, 4 e 8 Mg ha-1 (base seca) e o sistema de produção utilizado nesse período foi a sucessão soja / aveia-preta. Em cada um dos cultivos avaliou-se características nutricionais e de produtividade das culturas e a emissão de CO2 a partir do solo. Ao final do estudo foram coletadas amostras de solo para análise química básica, fracionamento da MO, C microbiano e estoque de C. A aplicação continuada de LC promoveu aumento do pH do solo e do teor de macronutrientes, principalmente Ca, bem como maior produção de matéria seca e acúmulo de nutrientes na parte aérea da aveia-preta. O LC também promoveu maior acúmulo de C nas plantas e maior atividade dos microrganismos do solo, o que acarretou em maior teor de C da biomassa microbiana (até 390 mg kg-1 na camada superficial), maior decomposição de MO leve e, consequente maior fluxo de CO2 para atmosfera (de 4,8 a 6,2 µmol m-2 s-1). Aplicações de longa data de lodo de esgoto (LB ou LC) resultam no aumento do teor de micronutrientes no solo, a ponto de Cu, Fe, Mn e Zn se apresentarem em níveis que podem ser prejudiciais às plantas. A produtividade da soja foi maior (até 3.232 kg ha-1) quando do uso de doses de lodos equivalentes a 4,5 a 5,3 Mg ha-1. A aplicação de lodos de esgoto resulta em aumento dos teores de C orgânico total (até 19,8 g kg-1), C da fração particulada (até 0,88 g kg-1) e C associado a minerais (até 19,0 g kg-1) somente na camada superficial do solo. Dentre as substâncias húmicas, a fração humina foi a que mais contribuiu com o estoque de C no solo (até 13,8 g kg-1). Após seis aplicações de lodo de esgoto, independentemente da dose e tipo de lodo, o estoque de C no solo aumentou apenas na camada superficial, e correspondeu a 106,2 Mg ha-1. / The study had as main objective to evaluate carbon (C) stock, changes in the amount of microbial C, quality of the soil organic matter (SOM) and CO2 emission as affected by sewage sludge applications in area under no-till. The experimental area, which shows a clayey Rhodic Ferralsol and is located in Botucatu, SP, has been conducted with the same treatments since 2002. The results of the present study, however, were obtained in the period from October 2012 to October 2014. A complete randomized blocks design arranged in a 2x4 factorial scheme and with four replicates was used. The treatments are represented by biennial application of two sewage sludge types (biodigested sludge - BS and centrifuged sludge - CS) in four rates: 0, 2, 4 and 8 Mg ha-1 (dry basis). The cropping system used in the study was a soybean/black oat succession. Yield and nutritional aspects of crops and CO2 emissions from soil were evaluated in each one of the cultivations. At the end of the study, soil samples were collected for analysis of soil fertility, OM fractionation, microbial C and C stock. The continued application of CS increased the pH and macronutrient levels in the soil, mainly Ca, as well as increased dry matter production and nutrient accumulation in aerial part of black oat. CS application also promoted greater accumulation of C in plants and greater activity of soil microorganisms, which led to a greater level of microbial biomass C (up to 390 mg kg-1 in the superficial layer), greater decomposition of light OM and consequently greater CO2 fluxes to the atmosphere (from 4.8 to 6.2 µmol m-2 s-1). Long time applications of sewage sludge (either BS or CS) resulted in increase of micronutrients levels in the soil, up to the point of Cu, Fe, Mn and Zn reach levels that may be harmful to plants. The soybean yield was higher (up to 3,232 kg ha-1) when sludge rates equivalent to 4.5 to 5.3 Mg ha-1 were used. The long-term application of sewage sludge increases the levels of total organic C (up 19.8 g kg-1), particulate fraction of C (up to 0.88 g kg-1) and C associated with minerals (up 19.0 g kg-1) only in the superficial layers of soil. Among the humic substances, the fraction that most contributed to the soil organic C (up 13.8 g kg-1) was humin. After six sewage sludge applications, regardless of the rate and type of sludge, the soil C stock increased only in the surface layer, and in total corresponded to 106.2 Mg ha-1. / FAPESP: 2011/21276-9 / CNPq: 152725/2012-1

O estudo teve por objetivo quantificar o estoque de carbono (C) e biomassa em indivíduos de Sibipiruna (Poincianella pluviosa) na arborização viária de Maringá, PR. A seleção das árvores amostra partiu do banco de dados para supressão da prefeitura municipal. Após fez-se a medição dos indivíduos avaliando-se: altura total (ht), altura da primeira bifurcação (hbif), altura do primeiro galho vivo (hgalho), altura de copa (hc), área de copa (Ac) e diâmetro à altura do peito (DAP). Para as condições do manejo e do meio urbano, consideraram-se: área livre, tipo de poda realizada, fitossanidade, qualidade de copa e tronco. Selecionou-se 24 árvores num intervalo diamétrico de 45,1 a 70,0 cm. Nas árvores abatidas, aferiu-se a biomassa fresca (madeira e casca do tronco, galhos e folhas). Para a copa fez-se uma sub-amostra (10,0 kg) para folhas e galhos finos e retirou-se uma alíquota para determinação do peso seco e teor de C. O peso úmido da copa (folhas e galhos finos), galhos grossos e madeira do tronco foi determinado em balança de carga (10.000,0 kg). Para a amostragem de madeira do tronco, foram retirados 3 discos de 5 cm de espessura na base, DAP e a 90% da altura. A casca foi separada dos discos, pesada e retirada uma alíquota para determinação de massa seca e C. As amostras foram enviadas a Universidade Tecnológica Federal do Paraná - Campus Dois Vizinhos e secas em estufa de circulação e renovação de ar, a 70,0ºC por 72 horas. Na fração madeira do tronco fez-se uma amostra composta dos discos das árvores. Após, as frações foram pesadas e moídas para análise química. Com base nas relações entre a quantidade de C e biomassa com as variáveis dendrométricas, construíram-se modelos de regressão linear para cada fração. Para o inventário de determinação do estoque de C estratificou o perímetro urbano (zonas norte, sul, centro, leste e oeste) onde se sorteou 10,0% dos bairros, totalizando 23 e realizou-se o censo. Na avaliação da influência do meio e manejo sobre o estoque de C e biomassa empregou-se regressão múltipla verificando-se a interdependência. A quantidade total de biomassa acumulada no perímetro inventariado foi de 1.696,4 Mg e de C foi de 734, 9 Mg, e para o perímetro urbano foi de 16.673 Mg de biomassa e 7.695,6 Mg de C estocados. A zona norte apresentou maior representatividade (53,1%) no estoque de C. A compartimentalização do estoque de C foi: galhos>madeira do tronco>folhas>casca do tronco. Os principais fatores que influenciaram o estoque de C foram: poda de levantamento e copa \"vigorosa\" (folhas); poda de levantamento, copa \"vigorosa\" e tronco \"íntegro\"(galhos); presença de fungos e copa \"vigorosa\" (casca); copa \"vigorosa\" e troncos \"injuriados\" (madeira); poda de levantamento, copa \"vigorosa\" e troncos \"injuriados\" (carbono total). Para a construção de protocolos de sequestro de C em árvores viárias é crucial o estudo do crescimento das árvores no meio urbano para observar as respostas do crescimento destas, e implementação de um manejo adequado para um o contínuo incremento do estoque de C nestas. / The study aimed to quantify sibipiruna trees (Poincianella pluviosa) carbon stock (C) and biomass, planted in the streets of Maringa, PR. Sample trees selection was based on the database for trees removal belonging to Maringá city hall. After that, trees were measured, evaluating: total height (Th), height at first fork (Haff), height of the first live branch (Hoflb), canopy height (Ch), crown area (Ca) and diameter at breast height (DBH). For the management and urban environment conditions, the following parameters were considered: open area, type of pruning, plant health, crown and trunk quality. Twenty-four (24) trees were with a DBH ranging from 45.1 to 70.0 cm, were selected. In felled trees, fresh biomass was measured (wood, bark, branches and leaves). For crown sampling, a sub-sample (10.0 kg) for leaves and fine branches was done and an amount of each component was taken for dry weight and C determination. Crown fresh weight (leaves and fine branches, thick branches and wood) was determined to load balance (10,000.0 kg). Wood sampling was done through disks (5.0 cm thickness) removal in the base, at DBH and at 90% of trunk length. Bark was removed from the disks, weighed and an amount aliquot taken for determination of dry matter and C. Samples were sent to Universidade Tecnológica Federal do Paraná - Campus Dois Vizinhos and oven (with air renovation and circulation), at 70.0 º C for 72 hours. In wood fraction, a composite sample from the tree\'s disks was done. After that, the fractions were weighed and milled for chemical analysis. Based on the relations between C amount and biomass and the dendrometric variables, were constructed linear regression models for each fraction. Inventory to determine C stock came from urban area stratification (northern, southern, central, east and west) where 10.0% of these neighborhoods were reflled, totalizing twenty-three (23); and them census was done. When evaluating the environment influence and the management on C stock and biomass, a multiple regression was used verifying interdependence. The total biomass accumulation by in the inventoried area was 1696.4 Mg, with 734.9 Mg C and for the urban area was 16,673.0 Mg of biomass and 7,695.6 Mg C storage. Northern area showed higher representativeness (53.1%) in C stock. The compartmentalization of C stock was: branches> wood > leaves> bark. Main factors that influenced the C stocks were: crown lifting pruning and vigorosus crown (leaves); survey crown lifting pruning, vigorosus crown and intact trunk (branches); fungi presence and vigorosus crown (bark); vigorous crown and trunks injuries (wood); crown lifting pruning, vigorosus crown and trunks injuries (total carbon). For the construction of protocols C sequestration in trees road is crucial to study the growth of trees in the urban environment to observe the growth of these answers, and implantation of appropriate management for a continuous increase in C stock these

Ainda que o conhecimento sobre a flora e a ecologia do cerrado tenha sido consideravelmente ampliado nas últimas décadas, persistem dificuldades relacionadas com a caracterização estrutural das fitofisionomias e pouco se sabe sobre as transformações fisionômicas que ocorrem nesta vegetação ao longo do tempo em áreas protegidas. Adicionalmente, mediante as mudanças climáticas, surgiu a demanda de quantificação de fitomassa e estoque de carbono em formações vegetais, entre os quais o cerrado. Os objetivos deste estudo foram: a) verificar se a classificação fisionômica de três fisionomias de cerrado reflete diferenças florísticas e estruturais; b) caracterizar a dinâmica espaço-temporal das fisionomias de cerrado; c) quantificar a fitomassa dessa vegetação e sua contribuição para estoque de carbono; d) avaliar a aplicabilidade de dados de sensoriamento remoto para estimar a fitomassa do cerrado. A pesquisa foi desenvolvida na Estação Ecológica de Assis (EEcA) localizada no estado de São Paulo. O cerrado típico, cerrado denso e cerradão foram caracterizados florística e estruturalmente e comparados para verificar se podem ser considerados distintos. Foram alocadas 30 parcelas de 20 x 50 m, sendo 10 parcelas para cada um dos tipos fisionômicos. Os indivíduos de espécies lenhosas com DAP \'> OU =\' 5 cm foram identificados e medidos. As fisionomias mostraram-se estruturalmente distintas, em classes de densidade, área basal e altura média das árvores e o melhor descritor para classificá-las, por ser pouco variável com o critério de inclusão, é a área basal (\'M POT.2\'/ha). Floristicamente, há diferenças apenas entre o cerradão e as fisionomias savânicas. Analisou-se a dinâmica espaço-temporal das fisionomias de cerrado, ao longo de 44 anos, com base em aerofotos (1962, 1984 e 1994) e imagens QuickBird (2006). Após a criação da unidade de conservação e devido à suspensão das atividades antrópicas (fogo e agropecuária), tem ocorrido um adensamento da vegetação, em que áreas de campo foram ocupadas por fisionomias de maior fitomassa, o cerradão correspondendo, em 2006, 91,43% da EEcA. Analisou-se, em particular, a oscilação na área ocupada por uma espécie invasora de samambaia (Pteridium arachnoideum). As imagens de 1994 e 2006 mostram que espécies arbóreas estão aumentando em densidade e cobertura em meio às manchas de samambaias e, em campo, constatou-se que a fitomassa das samambaias está diminuindo consideravelmente sob as copas das árvores. A fitomassa do cerrado stricto sensu e cerradão da EEcA foi estimada por meio de equações alométricas. Utilizaram-se parcelas de 20 x 40 m, sendo 20 parcelas para cada fitofisionomia. Utilizou-se regressão robusta com reamostragem Bootstrap para explorar as relações entre a fitomassa aérea do cerrado e as imagens do QuickBird e TM/Landsat, índices espectrais de vegetação (IV), componentes principais (CP), modelo linear de mistura espectral (MLME). Na EEcA, os valores médios de fitomassa aérea (23,22 Mg/ha) e total (28,88 Mg/ha) do cerrado stricto sensu foram próximos aos descritos na literatura para o cerrado do Brasil Central e os valores médios de fitomassa aérea (98,18 Mg/ha) e total (118,36 Mg/ha) do cerradão aproximaramse aos descritos para florestas estacionais. As bandas espectrais dos sensores QuickBird e TM apresentaram correlações fracas a moderadas com a fitomassa aérea de cerrado. As transformações espectrais (IV e CP) melhoram, em geral, a predição da fitomassa aérea de cerrado, contudo as correlações se mantiveram entre fracas e moderadas. / Even though knowledge on the ecology and flora of cerrado vegetation has considerably improved in recent years, gaps are still remaining on structural differentiation of the cerrado physiognomies and few is known about cerrado vegetation dynamics after protection from human pressure. In addition, before the climate changes, phytomass and carbon storage quantification has been a new challenge for different vegetation types, including the cerrado physiognomies. The present study was carried out with the aim of a) to characterize three cerrado physiognomies to verify if they are structurally and floristically distinct; b) to analyze the vegetation dynamics in time and space, to verify if the vegetation is undergoing a sucessional process, whose structural climax will be a forest physiognomy; c) to quantify phytomass in different physiognomies and their contribution to carbon stock; and d) to assess the application of remote sensing techniques to estimate the cerrado phytomass in large scale. This study was carried out at Assis Ecological Station (EEcA), located in the southwestern São Paulo state, Brazil. This protected area preserves one of the few brazilian cerrado (savanna) biome remnants in the State. Three distinct physiognomic types of cerrado (typical cerrado, dense cerrado and woodland cerrado) were floristically and structurally characterized and submitted to comparative analyses to verify if they can, or not, be considered as separate vegetation types within the cerrado gradient. Thirty permanent plots (20 x 50 m each) were set, ten in every cerrado type, and all woody individuals with DBH \'> OR =\' 5 cm were measured and identified. The three types of cerrado under comparison are structurally distinct in terms of density, medium height and basal area (\'M POT.2/ha), the last being considered as the best and more precise descriptor to classify the physiognomies of the cerrado vegetation. The woodland cerrado is also distinct by its flora, but the two open physiognomies (dense cerrado and cerrado stricto sensu) are floristically very similar. The dynamics of the vegetation types along 44 years in the studied area was analyzed by using aerial photographs (1962, 1984 and 1994) and QuickBird images (2006). After protection from human pressures (fire and agriculture), the woody vegetation density and phytomass has continuously increased, with open physiognomies tending to disappear and woodland cerrado replacing them. Surprisingly, the area covered by the invasive fern Pteridium arachnoideum has also decreased, replaced by sparse or clustered trees. The cerrado phytomass was estimated by allometric equations. Forty plots (20 x 40 m each) were used, twenty in every cerrado type - cerrado stricto sensu and woodland cerrado. Robust Regression and Bootstrap methods were used to explore relationships between aboveground cerrado phytomass and remote sensing data of QuickBird and Landsat Thematic Mapper (TM) sensors (spectral bands, vegetation index - VI, principal components - PC, linear spectral mixture model LSMM). Valors of medium phytomass obtained for the cerrado stricto sensu at Assis Ecological Station were close to those described in the literature for Central Brazilian cerrado. The valors of medium phytomass of the woodland cerrado were close to those described for seasonal forests. Spectral bands of QuickBird and TM sensors presented weak to moderate correlations with the aboveground cerrado phytomass. In general, spectral transformations (VI and PC) improved the prediction of the cerrado phytomass, however the correlation remained from weak to moderate.

Depuis quelques années la sylviculture intensive prend une grande ampleur afin de rapprocher la source de fibres des usines, d'accroître la productivité des plantations, et de diminuer la pression de coupe sur les forêts naturelles. Toutefois un débat sur le type d'aménagement optimal des plantations oppose l'aménagement mono- et pluri-spécifique. Il est important de mieux comprendre le fonctionnement de ces écosystèmes pour en effectuer une bonne gestion et d'optimiser les services écosystémiques que ces plantations fournissent. La décomposition des litières et le recyclage des nutriments sont des processus complexes essentiels au fonctionnement des écosystèmes. Ainsi mon projet de thèse visait à mieux comprendre l'influence de la mixité de deux essences forestières, à savoir l'épinette blanche et le peuplier hybride, en comparaison à des plantations pures sur le processus de décomposition des litières et le stockage de carbone. Les résultats de cette étude ne montrent pas d'amélioration du processus de décomposition avec le mélange du peuplier et de l'épinette ou de leurs litières. En revanche, le mélange de ces deux espèces en plantation tamponne les effets contrastés du peuplier et de l'épinette observés dans les plantations monospécifiques. De plus, le stockage de carbone et la productivité du peuplier sont améliorés dans les plantations mixtes par rapport aux plantations monospécifiques. Les herbacées semblent être bénéfiques pour la diversité d'organismes et favorisent la libération d'azote des litières d'arbres. Cet aspect pourrait contrebalancer l'effet négatif de la présence d'herbacées qui entrent en compétition avec les arbres pour les ressources. / The use of trees under intensive management is particularly important for rapid fibre production and for reduce cutting pressure on natural forests in boreal regions. However, a debate on the best type of plantation management opposes the mono-and pluri-specific management. Despite the possible antagonistic effects on productivity, it seems that mixed plantations would have benefits on soil properties, environmental stability, but also to maintain biodiversity and aesthetic value. It is important to better understand the functioning of these ecosystems to make good management in order to optimize ecosystem services of these plantations. Litter decomposition and nutrient cycling are essential process for the ecosystems functioning. My thesis project was to better understand the influence of the mixing of two tree species planted in comparison to monospecific plantations, namely white spruce and hybrid poplar, on the litter decomposition process and carbon storage. The results of this study showed no improvement in the decomposition process with the mixture of poplar and spruce in plantation or by their litters mixture. However, the mixture of the two species in plantation buffers the contrasting effects of poplar and spruce observed in monospecific plantations. In addition, carbon storage and productivity of poplars are improved in mixed plantations compared to monospecific plantations. Herbaceous litter appears to be beneficial for the abundance of organisms and promote the release of nitrogen from tree litter. This could offset the negative effect of the presence of grasses that compete with trees for resources.

The wild boar is known to disturb the forest floor by rooting in the soil as they search for food. Soil is a vital part of the carbon cycle and stores large amounts of carbon. There is limited knowledge on how this feeding behavior may alter the content of organic matter in the soil and consequently the ability of the soil to store carbon. The objective of this study was to examine the effects of rooting on organic matter concentration by (1) comparing soil from rooted and un-rooted plots and (2) investigating whether the density of rooted areas within each plot affects organic matter concentration. Our results showed no effects of rooting on organic matter concentration. The soil in our study area contained very high concentrations of organic matter (83%) which could have been a factor in why no effects were detected. Our overall results indicate that rooting does not, in the short term, affect the ability of the soil to store carbon in a coniferous forest in southern Sweden. However, this does not exclude rooting as a potential factor influencing soil carbon storage, as several other studies have detected significant differences in soil concentration. The complexity of ecosystems and factors influencing their properties leads to contrasting results between studies. It is relevant in a climate change perspective to further investigate the effects rooting may have on carbon storage in the soil.

There is an urgency within the building sector to reduce its greenhouse gas emissions and mitigate climate change. An increased proportion of biobased building materials in construction is a potential measure to reduce these emissions. Life cycle assessment (LCA) has often been applied to compare the climate impact from biobased materials with that from e.g. mineral based materials, mostly favouring biobased materials. Contradicting results have however been reported due to differences in methodology, as there is not yet consensus regarding certain aspects. The aim of this thesis is to study the implications from non-traditional practices in climate impact assessment of timber buildings, and to discuss the shortcomings of current practices when assessing such products and comparing them with non-renewable alternatives. The traditional practices for climate impact assessment of biobased materials have been identified, and then applied to a case study of a building with different timber frame designs and an alternative building with a concrete frame. Then, non-traditional practices were explored by calculating climate impact results using alternative methods to handle certain methodological aspects, which have been found relevant for forest products in previous research such as the timing of emissions, biogenic emissions, carbon storage in the products, end-of-life substitution credits, soil carbon disturbances and change in albedo. These alternative practices and their implications were also studied for low-carbon buildings. The use of non-traditional practices can affect the climate impact assessment results of timber buildings, and to some extent the comparison with buildings with lower content of biobased building materials. This effect is especially evident for energy-efficient buildings. Current normal practices tend to account separately for forest-related carbon flows and aspects such as biogenic carbon emissions and sequestration or effects from carbon storage in the products, missing to capture the forest carbon cycle as a whole. Climate neutrality of wood-based construction materials seems like a valid assumption for studies which require methodological simplification, while other aspects such as end-of-life substitution credits, soil carbon disturbances or changes in albedo should be studied carefully due to their potentially high implications and the uncertainties around the methods used to account for them. If forest phenomena are to be included in LCA studies, a robust and complete model of the forest carbon cycle should be used. Another shortcoming is the lack of clear communication of the way some important aspects were handled. / <p>QC 20150310</p>

Koldioxidhalterna stiger i världen, vilket bidrar till global uppvärmning. Skogen har en viktig roll i klimatarbetet då stora mängder kol finns lagrad i skog och mark. Speciellt mycket kol finns i boreal skog, som bland annat finns i norra Sverige. Idag pågår en debatt huruvida det är mer fördelaktigt att behålla gammal skog som kolsänka, eller avverka den för att ge plats åt yngre träd. Syftet med litteraturstudien var att ge en klargörande bild över hur åldern på boreal skog påverkar ekosystemets kolbalans, genom att undersöka skogens kolupptagningshastighet samt möjlighet till kollagring. Studien visade att äldre skog har ett större totalt kollager, att medelåldrig skog har högst tillväxthastighet (nettoekosystemproduktion, NEP och nettoprimärproduktion, NPP) samt att NEP är negativ de första 10 åren. Studien visade på osäkerhet kring kolupptag i gamla skogar. Flera variabler, såsom substitution, störningar och biologisk mångfald är inte undersökta i studien och behövs tas i beaktning vid beslutsfattande. Trots detta, antyder litteraturstudien att det är fördelaktigt att låta gammal skog stå kvar som kolsänka, eftersom koldioxidutsläppen behöver minska snarast. Ytterligare ett syfte med studien var att kartlägga de missuppfattningar elever, i senare delen av skolan, har gällande kolets kretslopp. Studien visade på missuppfattningar gällande fotosyntes och respiration hos växter, nedbrytarnas roll samt sammanblandning av begrepp. För att åtgärda problemet kan uppgifter göras där atomer följs över olika nivåer, för att sätta processerna i sitt sammanhang. Stort fokus gällande missuppfattningarna ligger på fotosyntes och respiration och inga artiklar hittades gällande exempelvis det snabba, respektive långsamma, kretsloppet. Få studier är gjorda på svenska elever och då svensk kursplan lägger fokus på samband mellan olika nivåer kan missuppfattningarna vara i annorlunda i Sverige. Hur missuppfattningarna ser ut i svensk skola är föremål för vidare forskning. / The amount of carbon dioxide is rising in the atmosphere, which contributes, to global warming. Since large amounts of carbon are stored in forests, forests play an important part the efforts to improve the environment. Boreal forests, found in e.g. the northern part of Sweden, store especially large amounts of carbon. Today it is being debated whether it is more beneficial for the environment to keep old forests as a carbon sink, or to cut them down in order to make room for younger trees. The purpose of this literature study was to clarify how the age of the forest affects the carbon balance of the ecosystem, by examining the forest’s rate of carbon sequestration and capability of carbon storage. The literature study concluded that older forests, in total, store larger amounts of carbon, while middle-aged forests have he highest growth rate (net ecosystem production, NEP, and gross primary production, GPP) and that NEP is negative in the first ten years. The study showed some uncertainty concerning carbon uptake in old forests. Several variables, such as the effects of substitution, disturbances and biodiversity were not examined in this study and need to be further considered before making decisions. However, the literature study suggests that it is more beneficial to leave old forests as a carbon sink, since emissions of carbon dioxide urgently need to be reduced. Another purpose of the study was to examine the misconceptions that students, in the later school years, have regarding the carbon cycle. This study found misconceptions concerning photosynthesis and respiration in plants, the role of decomposers, as well as getting concepts mixed up with one another. To solve this problem, assignments could be designed where atoms are traced between different levels, in order to put the processes in context. A large part of the focus regarding these misconceptions has been on photosynthesis and respiration and no articles were found regarding e.g. the fast; and the slow; carbon cycle. Few studies of Swedish students have been made and since the Swedish curriculum focuses on the relationship between different levels, the misconceptions might be different in Sweden; what these misconceptions could be in Swedish schools is yet to be investigated.

För klimatet spelar skogen en viktig roll eftersom den binder in koldioxid från atmosfären. Genom fotosyntes binds kolet in i biomassan och när organiskt material bryts ned bidrar det till kolinlagringar i marken. Idag finns det många studier om skogens kolinlagringar, men de undersöker endast nettoinbindningen av kolet i skogen och få studier visar hur mycket kol som totalt är inlagrat i en skog. Det finns inga studier om hur det ser ut i Sverige och det finns få studier som visar på skillnaden i kolinlagring mellan en produktionsskog och en urskog. I den här litteraturstudien presenterar jag hur mycket kol som är inbundet i den svenska skogen och hur det skiljer sig mellan produktionsskog och urskog. Genom att applicera data från en studie som undersökte hur mycket kol som är inbundet i skogen i Kanada på den svenska skogen kom jag fram till att det finns totalt mellan 5 413 och 6 798 miljoner ton kol inlagrat i den svenska skogen, men mer kol skulle kunna lagras. Medelåldern för när träd slutavverkas är i Sverige 101 år. Jag kom fram till att det lagras in ungefär 53 till 75 ton mer kol per hektar i en skog som är äldre än 140 år än i en skog som är mellan 101 och 120 år. Resultatet visar att det binds in mer kol i en urskog än i en produktionsskog och att det är viktigt att bevara de urskogar som idag finns för att kunna möta de klimatproblem vi står inför. / For the climate, the forest plays an important role because it binds carbon dioxide from the atmosphere. Through photosynthesis, carbon is bound into the biomass and degradable organic material contributes to carbon storage in the soil. There are many studies on the forest carbon deposits, but they only examine the net binding of carbon, and few studies show how much carbon is stored in total. There are no studies on what carbon storage looks like in Sweden and few studies that show the difference in carbon storage between production forests and old-growth forests. In this literature study, I present how much carbon is bound in Swedish forests and how it differs between production forest and old-growth forest. By applying data from a study that examined how much carbon is bound in Canadian forests on Swedish forests, I concluded that there is a total of between 5 413 and 6 798 million tonnes of carbon stored in Swedish forests, but more carbon could be stored. In Sweden, the average age for when trees are felled is 101 years. I concluded that approximately between 53 and 75 tonnes more carbon per hectare is stored in a forest that is older than 140 years than in a forest that is between 101 and 120 years. The results show that more carbon is bound in an old-growth forest than in a production forest and that it is important to preserve the old-growth forests to reduce the climate problems we face.

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