In the dominantly small-scale subsistence agricultural system of Ethiopia, where most of the organic inputs are not returned to soil and land is not used based on its best suitability, the contribution of agriculture to climate change mitigation/adaptation through reduction of greenhouse gases emission is undermined. When this low-input agricultural practice is coupled with rugged topography, high population pressure, generally low soil fertility, and looming climate change, ensuring food and nutrition security of society as well as sustainable use of land resources is practically impossible. Under such circumstances, finding alternative land uses, through scientific investigation, that meet the triple mandates of climate-smart agriculture under current and future climate is imperative. In view of this, a study was conducted in Hades Sub-watershed, eastern Ethiopia, to evaluate the carbon stock of major land uses, evaluate suitability of land for rainfed production of sorghum (Sorghum bicolor L.), Maize (Zea mays L.), coffee (Coffea arabica), upland rice (Oryza sativa L.) and finger millet (Eleusine coracana L.), and project biomass production of late-maturing sorghum and maize varieties under changing climate and its contribution to carbon sequestration and reduction of greenhouse gases (GHGs) emission. Soil and vegetation samples were collected following recommended procedures. Secondary data on required crop parameters were collected for model calibration and validation in the biomass projection study made using the AquaCrop v6.0 model. Climate data of the study area was obtained from the National Meteorology Agency of Ethiopia and analyzed following standard procedures. Near-century (NC) (2017-2039) and Mid-century (MC) (2040-2069) climate was projected under two emission scenarios (RCP4.5 and RCP8.5) using four models (CNRM-CERFACS-CNRM-CM5, ICHEC-EC-Earth, MOHC-HadGEM2-ES, and MPI-M-MPI-ESM-LR) and a Multi-model Ensemble. Biomass production projection, for the climate projected under the two emission scenarios using the four models and the ensemble, was made for late-maturing sorghum (Muyira-1) and maize (BH661) varieties. From the projected biomass, organic carbon and its equivalent CO2 were estimated. Furthermore, adaptation measures, involving adjusting planting dates and irrigation, under the changing climate were evaluated for their influence on biomass production under the time slices, RCPs, and models mentioned above. The carbon stock assessment study was conducted on four major land uses (cultivated, grazing, coffee agroforestry, and forest lands) identified in the study area. The land suitability assessment, using the maximum limitation method, study was conducted on four soil mapping units identified in the sub-watershed. Results indicate that total organic carbon stock (soil, litter plus live vegetation) in the sub-watershed ranged from 138.95 ton ha-1 in the crop land to 496.26 ton ha-1 in the natural forest. The soil organic carbon stock was found to be relatively higher than that of the vegetation carbon stock in the natural forest and coffee agroforestry land uses. The results of suitability evaluation revealed that the maximum current and potential (after corrective xix measures are taken) land suitability class for production of late-maturing sorghum (180-240 days cycle), maize (180-210 days crop cycle), finger millet (120 – 150 days cycle) and coffee in the sub-watershed is marginally suitable (S3c). The maximum current and potential land suitability for upland rice (120 days) is not suitable (N2c). The major permanent limiting factor is low mean temperature (14.6 C) of the growing period in the study area as compared to the optimum temperature required for optimum growth of the selected crops. The major soil and landscape limitations include steep slope, poor drainage of low-lying areas, shallow effective root zone in the upper slopes, low organic matter and available P for sorghum and maize, high pH for maize and wetness for coffee. In all the climate models and emission scenarios, minimum and maximum temperature increment is high during June-July-August-September (JJAS) compared with the other seasons. The modest rise in minimum temperature and the slight increment of maximum temperature during the crop growing seasons (February-March-April-May (FMAM) and JJAS will benefit late-maturing sorghum and maize production in the study area. For the same model, the projected biomass yield and organic carbon sequestration of the two crop varieties varied with time slice and the type of emission scenario used. Generally, increasing biomass production and carbon sequestration were projected for Mid-century (MC) than Near-century (NC) for most of the models used. Late planting would increase sorghum biomass yield and the corresponding organic carbon as compared to early planting as projected by most of the models under both RCPs. Most models predicted an increase in maize biomass yield and organic carbon sequestration if supplementary irrigation is used. The results of this study indicate that the current land uses are not enhancing carbon sequestration because of their exploitative nature and the soil/landscape and climate are not optimum for production of the crops studied. The rise in temperature in the coming 50 years is expected to create a more favorable condition for production of late-maturing sorghum and maize varieties. In order to enhance carbon sequestration, soil productivity and crop yield, and reduce greenhouse gas emissions, the current land uses and their management require re-visiting. / College of Agriculture and Environmental Sciences / Ph. D. (Environmental Sciences)

The daunting tasks of responding to climate change and ensuring sustainable development (SD) are high on the political agenda among world leaders. From the onset, the clean development mechanisms (CDM) outlined in Article 12 of the Kyoto Protocol (KP), state that CDM activities should contribute to SD in the host country while reducing greenhouse gas (GHG) emission. Nevertheless, many scholars have criticized CDM for failing to deliver on its twin objectives. In Ethiopia in particular, there was lack of afforestation/reforestation (A/R) CDM research specific to the nation; specifically, research as to whether A/R-CDM met the stipulated twin objectives of SD and mitigation (reducing GHG). This study was conducted in the Humbo district of Wolyaita Zone, Southern Nations - Nationality and People Regional (SNNPR) state of Ethiopia, where A/R-CDM was implemented in pursuit of these twin objectives. Humbo is located between 6°46’48.47 and 6°41’04.28N; and between 37°48’35.44 and 37° 55’14.51E, between altitudinal gradients 1200 and 1900 m.a.s.l. The climate of the study area is characterized by annual temperatures between 25°C and 28°C, and by total annual rainfall between 800 to 1000 mm. The objectives of the study were to quantify the change of above ground and below ground carbon pools of native tree species; to assess the attractiveness of FMNR forestry practices; to examine A/R-CDM contributions to community level SD; and to assess the effectiveness of climate change mitigation policy founded on native tree species-based A/R-CDM. Data regarding above ground biomass (AGB) and below ground biomass (BGB) carbon pools of native tree species was collected through non-destructive techniques to quantify the change in carbon sequestration and associated carbon trading. A multi-stage random cluster household (HH) sampling approach was used to assess the attractiveness of farmer managed natural regeneration (FMNR) forestry practice. To examine the contribution of A/R-CDM to community level SD, three dimensions of SD were evaluated, namely; (local) environmental, social, and economic. Two indicators were considered per each dimension. With regard to local environmental SD, community access to natural resources, as well as changes to the local climate were considered. With regard to the social dimension, job creation and changes to social support structures were considered. With regard to the economic dimension, economic activities of the area and local skill development were considered. Focus group discussions and key informant interviews were used to triangulate the survey as well as to assess policy perspectives. Results revealed that the Humbo native tree species based A/R-CDM, which employed FMNR forestry practices, sequestered a net total of 73,138; 84,848; 103,769 and 111,657 tCO2e along 2011, 2014, 2015 and 2016 years, respectively, across 2,728 ha. In terms of carbon leakage due to fuel wood collection activity displacement, a net zero was found since the average volume of fuelwood collected from the project area, after the area was closed off, was found to be 5.1 - 6.1 M3, while before the area was closed off, that number was 4.3 M3. This was due to the project employing FMNR forestry practices. Similarly, the leakage due to livestock grazing activity displacement also was found to be a net zero, since the number of animals grazing on land adjacent to the project area after four years of the area’s being closed off reached 11,383 cattle, 429 donkeys and 4,108 goats, unlike 8,684 cattle and 2,288 goats before the project. In other words, the number of livestock owned by farmers on the land adjacent to the project site was not adversely affected by the closing off of the site, which prevented grazing on the area allocated to A/R-CDM. The livestock management training provided by project developer improved the farmers’ rearing efficiency. Another expected leakage due to soil pitting for A/R was also found to be nil since soil disturbance did not take place because of FMNR practices. These results indicated that systematic regeneration of native tree species through FMNR forestry practices is an effective method to develop carbon sinks. From the point of view of FMNR attractiveness, the results revealed that the practice improved land cover change. The use of FMNR avoided the projected eight years reforestation investment cost of US$ 2,751,312.00 which could have been used if plantation forestry was undertaken. This showed that Humbo A/R-CDM might not have happened if FMNR is had not been introduced, as CDM has no pre-finance mechanism. With regard to community level SD contributions, the establishment of forest protection and development farmers’ cooperatives, as well as the granting of communal land-user rights certification, resulted in legal ownership of the land to the community, whereas before, the land was considered “no man’s land,” and subject to open access. The land-user rights and carbon ownership in turn empowered the community to sign a contract with an international carbon credit buyer. In terms of the local microclimate, the regeneration of native tree species was correlated with increased rainfall in the area in June, July, August and September (JJAS) and March, April and May (MAM). This suggested that the native tree species based A/R-CDM project played a role in improving the local microclimate. In terms of sociological SD, the study showed that new employment opportunities were created including tree pruning, thinning, forest guarding, and jobs at the community warehouse and community flourmill. The availability of employment opportunities was significantly higher for those who participated in the Humbo A/R-CDM, when compared to those who didn’t. In terms of social support structures, in less than ten years, seven Humbo A/R-CDM project owner farmers’ cooperatives, initially established as owners of the project, evolved into one forest protection and development Union. This enabled the institutionalization of grassroots organizations towards a common communal and international agenda of care for the environment. In terms of economic effects, the project enabled a carbon credit contract worth a total of US$ 3,873,298.00, signed at the sell rate of US$ 4.4 per tCO2e, for a total of 880,295 tCO2e across a 30 year crediting period. This is a new business model for the community, the country, and global businesses, all doing their part in climate change mitigation - CDM. As of the first A/R-CDM verification, the community received a total of US$ 321,807.2 in 2011. Consequently, the community received 373,331.2 in 2014, 456,583.6 in 2015 and 491,290.8 in 2016. In terms of revenue from logging, selective harvesting is planned to take place in years 12, 24 and 36. The community is projected to earn at least US$ 15,150.00 per ha1 (a total of US$ 3.9 million) from the first forest harvest in year 12 alone. These benefits in emission reduction (ER) and SD suggest that massive cross-dimensional benefits were foregone due to the country’s refusal to welcome A/R-CDM in its first commitment period, despite having 36,434,400 ha of land eligible for A/R. The research results in the area of policy perspectives indicated that the Humbo A/R-CDM project, the only one of its kind in Ethiopia, was made possible by environment related constitutional provisions, especially those pertaining to land-user rights, and the existence of a nationally standardized definition of forest that complies with international range. Additionally, the timely ratification of the Kyoto Protocol (KP), the establishment of a designated national authority (DNA) and a letter of approval by the DNA to the project developer were found to be enablers. Yet, defining land use, clarifying carbon ownership rights and bringing an inclusive benefit sharing mechanism for forest carbon are among the key instruments the country has yet to put in place to prove local readiness for such development opportunities. The Humbo A/R-CDM also undertook voluntary assessments to obtain additional certification in the form of the Climate Community Biodiversity (CCB) certification, and was certified to be of gold standard for its premium. However, there were no benefits to the host community and project developer from the CCB gold standard certification. Such ambiguity could have been cleared from the onset. This implied whenever going for market and/or result based climate change mitigation, it is necessary to understand the provisions. This study revealed that the Humbo native tree species-based A/R-CDM via FMNR forestry practices met the CDM twin objectives as specified in Article 12 of the KP in 1997, namely the double aims of achieving mitigations of GHG emissions and assisting developing countries inSD. Yet, more research is needed to understand all eligible A/R carbon pools sequestered at Humbo A/R-CDM site. / Environmental Sciences / Ph. D. (Environmental Management)

Accounting / M.Com. (Accounting0

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Carbon dioxide (CO2) is seen as one of the main contributors to global warming. The use of fossil fuels for power production leads to large quantities of carbon dioxide being released into the atmosphere. The released CO2 can, however, be captured by retrofitting capture units downstream from the power plant called Post Combustion Carbon Dioxide Capturing. Post combustion CO2 capture can involve the reactive absorption of CO2 from the power plant flue gas steam. Reactive solvents, such as monoethanolamine (MEA), are used for capturing the CO2 and the solvent is regenerated in a desorber unit where the addition of heat drives the reverse reaction, releasing the captured CO2. However, the large energy requirement for solvent regeneration reduces the viability of employing CO2 capture on an industrial scale. This study focused on establishing a facility for CO2 capture studies – the main aim being the construction and validation of the results produced by the pilot plant facility. A secondary aim of this study was developing an Aspen Plus® Simulation method that would simplify simulating the complex CO2 capture process. Results from the simulation were to be compared to that of the pilot plant experiments. A pilot plant facility with a closed gas system, allowing gas recycling from both the absorber and the stripping columns, was set up. The absorber column (internal diameter = 0.2 m) was set up to allow one to obtain information regarding gas- and liquid temperatures and compositions at various column heights. Online gas analysers are used for analysing the gas composition at various locations in the absorber column. The pilot plant was initially commissioned with 20 weight % MEA in aqueous solution; however the main validation experiments were conducted with 30 weight % MEA in aqueous solution. 30 weight % MEA (aq) is generally used as the reference solvent for pilot plant studies. Pilot plant results with regards to the carbon dioxide concentration profiles for the absorber column as well as the regeneration energy requirement and capture rates compared well to literature data. The Aspen Plus® simulation was also set up and validated using published pilot plant data. The comparison of the pilot plant results from this study, to the results from the Aspen Plus® Simulation, showed good agreement between the two. The Aspen Plus® Simulation could further be used to validate pilot plant data that has been gathered outside the range of reported CO2 capture efficiencies. The Aspen Plus®model was evaluated at liquid-to-gas ratios of 1.7 and regeneration energies matching the pilot plant results. It was found that the model under predicts the capture efficiency of CO2 with an average of 4.0%. The model was corrected for this error at liquid-to-gas ratios of 2 and the fit of the model to pilot plant results improved considerably (R2-value = 0.965). Pilot plant repeatability was investigated with both 20 weight %- and 30 weight % MEA in aqueous solution. Temperature- and gas concentration profiles from the absorber column showed good repeatability. The maximum deviation of the regeneration energy and the capture efficiency from the calculation means were ±0.72% and ±1.40% respectively. The aims of this study have been met by establishing, and validating the results of a pilot plant facility for carbon dioxide capture studies. It has been shown that the pilot plant produces repeatable results. Results from the Aspen Plus® Simulation were validated and also match results from the established pilot plant setup. The simulation may prove to provide valuable information regarding the optimal operating conditions for the pilot plant and may aid in performing a full parametric study on the CO2 capture process. / AFRIKAANSE OPSOMMING: Koolstofdioksied (CO2) word geklassifiseer as een van die bekendste kweekhuisgasse wat ʼn groot bydra lewer tot aardverwarming. Die gebruik van fossielbrandstowwe om na die energiebehoeftes van die mens om te sien lei daartoe dat groot hoeveelhede koolstofdioksied, hoofsaaklik vanaf kragstasies, vrygestel word in die atmosfeer. Daar is verskeie maniere hoe die CO2 uit die uitlaatgas van kragstasies verwyder kan word – die vernaamste hiervan is bekend as die Na-verbranding opvangs metode. Die opvangs van CO2 na verbranding van fossielbrandstowwe vir kragproduksie kan vermag word deur van reaktiewe absorpsie tegnieke gebruik te maak. Mono-etanol-amien (MEA) kan vir hierdie doeleindes aangewend word deur dit, in ʼn absorpsiekolom, in kontak te bring met die CO2. Die gereageerde oplosmiddel word geregenereer deur die oplosmiddel te verhit in ʼn stropingskolom. ʼn Bykans suiwer CO2 stroom word vrygestel. Die implementering van hierdie opvangtegniek op industriële skaal lei egter tot groot energieverliese vir die kragstasies. Die hoofrede hiervoor is die hoeveelheid energie wat benodig word om die oplosmiddel te regenereer vir hergebruik. Die hoofdoel van hierdie studie was gemik op die oprigting en inwerkstelling van 'n navorsingsfasiliteit vir studies aangaande die na-verbranding opvangs van CO2. Dit het behels die ontwerp, konstruksie en stawing van gelewerde resultate met resultate in die literatuur. 'n Sekondêre doel van hierdie studie was die metode-ontwikkeling vir die opstel van 'n Aspen Plus® Model wat die simulasie van die CO2 opvangsproses met ʼn reaktiewe oplosmiddel, MEA, vereenvoudig. Gesimuleerde resultate is vergelyk met resultate uit die literatuur. Die toetsaanleg, met 'n geslote gas stelsel, maak voorsiening vir die hersirkulering van gas wat vir eksperimentele doeleindes gebruik word. Die absorpsie kolom (interne diameter van 0,2 m) is opgestel sodat informasie aangaande die gas- en vloeistof temperature, sowel as gas- en vloeistof komposisies vanaf verskillende kolomhoogtes, bekom kan word. ʼn Aanlyn CO2 analiseerder word gebruik om vir CO2 in die prosesgas te analiseer. Die toetsaanleg is aanvanklik in bedryf gestel met ʼn 20 massa % MEA in waterige oplossing; die hoof eksperimente is egter uitgevoer deur van 30 massa % MEA in waterige oplossing gebruik te maak. Die laasgenoemde oplosmiddel word algemeen gebruik in die CO2 opvangs verwante navorsingsveld. Die resultate van die toetsaanleg, vergelyk goed met resultate in die literatuur. Die gesimuleerde Aspen Plus® resultate is ook vergelyk met resultate in die literatuur en die gevolgtrekking is gemaak dat die simulasie gebruik kan word om redelike akkurate voorspellings van die werklike prosesresultate te gee. Die simulasie is verder ook gebruik om resultate, verkry vanaf die opgerigte toetsaanleg, te verifieer en ʼn goeie ooreenstemming tussen die gesimuleerde en die eksperimentele resultate is waargeneem. ʼn Verder gevolgtrekking aangaan die Aspen Plus® simulasie metode was dat dit in die toekoms ʼn groot doel kan dien in die optimeringsproses van toetsaanlegte waar navorsing aangaande die na-verbranding opvang van CO2 gedoen word. Die Aspen Plus® model is geëvalueer by ‘n vloeistof-tot-gas-verhouding van 1,7 en ooreenstemmende toetsaanleg resultate, aangaande die hoeveelheid energie wat ingesit is vir die regenerasie van die oplosmiddel. Die onakkuraathede in die model, met betrekking tot die voorspelling van die hoeveelheid CO2 wat vasgevang sal word, is hierdeur bepaal en die model is daarvoor aangepas. Resultate van die verbeterde model vergelyk baie goed met die toetsaanleg resultate – ʼn R2-waarde van 0.965. Die herhaalbaarheid van die toetsaanleg resultate is ondersoek en ʼn goeie herhaalbaarheid van die temperatuur- en CO2 konsentrasieprofiele is verkry. Die toetsaanleg dui ook goeie herhaalbaarheid met betrekking tot die effektiwiteit waarmee die CO2 uit ʼn gasstroom verwyder word (± 1,40%), sowel as die hoeveelheid energie wat benodig word vir regenerering van die oplosmiddel (± 0,72%). Die doelwitte van hierdie studie is bereik deur die oprigting en verifiëring van resultate gelewer deur 'n toetsaanleg vir studies aangaande die na-verbrandingsopvang van CO2. Die herhaalbaarheid van toetaanleg resultate is bewys. Resultate van die Aspen Plus® simulasie stem ooreen met resultate in die literatuur sowel as resultate van die toetsaanleg wat opgerig is in hierdie studie.

Abstract In Paper [I], I develop the FOR-DICE model to analyze optimal global forest carbon management. The FOR-DICE is a simple framework for assessing the role of the boreal, tropical, and temperate forests as both a source of renewable energy and a resource to sequester and store carbon. I find that forests play an important role in reducing global emissions, especially under ambitious climate targets. At the global level, efforts should focus on increasing the stock of forest biomass rather than increasing the use of the forest for bioenergy production. The results also highlight the important role of reducing tropical deforestation to reduce climate change. In Paper [II], I develop the FRICE to investigate the role of two key efforts to increase the stock of forest biomass, namely, afforestation and avoided deforestation. FRICE is a multi-regional integrated assessment model that captures the dynamics of forest carbon sequestration in a transparent way and allows me to investigate the allocation of these actions across space and time. I find that global climate policy can benefit considerably from afforestation and avoided deforestation in tropical regions, and in particular in Africa. Avoided deforestation is particularly effective in the short run while afforestation provides the largest emissions reductions in the medium run. This paper also highlights the importance of not solely relying on avoided deforestation as its capacity to reduce emissions is more limited than afforestation, especially under more stringent temperature targets. In Paper [III], we investigate how uncertainties linked to the forest affect the optimal climate policy. We incorporate parameter uncertainty on the intrinsic growth rate and climate effects on the forest by using the state-contingent approach. Our results show that forest uncertainty matters. We find that the importance of including forest in climate policy increases when the forest is subject to uncertainty. This occurs because optimal forest response allows us to reduce the costs associated with uncertainty. In Paper [IV], we explore the implications of asymmetries in climate policy arising from not recognizing forest carbon emissions and sequestration in the decision-making process. We show that not fully including carbon values associated with the forest will have large effects on different forest controls and lead to an increase in emissions, higher carbon prices, and lower welfare.  We further find, by investigating the relative importance of forest emissions compared to sequestration, that recognizing forest emissions from bioenergy and deforestation is especially important for climate policy.

Land-use change is the single most important global driver of changes in biodiversity. Such changes in biodiversity, in turn, are expected to influence the functioning of ecosystems and their resilience to environmental perturbations and disturbances. It is widely recognised that the use of functional traits and functional diversity is best for understanding the causes and functional consequences of changes in biodiversity, but conceptual development has outpaced empirical applications. This thesis explores these ideas in grazing systems, which are expected to undergo rapid intensification of fertiliser use and grazing pressure to meet the growing global demand for livestock products. First, a flexible framework for measuring different facets of functional diversity is described, and a new multidimensional functional diversity index, called functional dispersion (FDis), is presented. Second, two vegetation sampling methods are compared with regard to their ability to detect changes in vegetation composition. Third, shifts in plant trait distributions following land-use changes are quantified and compared to null models, and a maximum entropy approach is used to quantify the direction and strength of selection on each trait. Fourth, it is shown that these shifts in trait distributions have cascading effects on primary production, litter decomposition, soil respiration, and ultimately soil carbon sequestration. Finally, data from 18 land-use intensity gradients are used to show that land-use intensification reduces functional redundancy and response diversity, two components of biodiversity that are thought to influence ecosystem resilience to future disturbances. This study illustrates (i) the importance of considering species functional differences to understand how plant communities react to changes in soil resource availability and grazing pressure, and (ii) how such changes directly, indirectly, and interactively control ecosystem functioning, as well as (iii) increasing the vulnerability of ecosystems to future disturbances.

Objetivando estudar o seqüestro de carbono em sistemas de restauração florestal e discutir suas potencialidades e entraves perante MDL florestal, este trabalho teve dois objetivos principais: i) quantificar taxas iniciais de seqüestro de carbono nos compartimentos aéreo, radicular, solo e serapilheira, de plantios de restauração da Mata Atlântica, com 20 espécies (10 pioneiras, 10 não pioneiras), submetidos a manejos contrastantes (usual e intensivo), instalados sobre pastagem de Brachiaria no espaçamento de 3 m x 2 m; e ii) comparar os estoques de carbono destes sistemas, ao final do sexto ano, com valores determinados em fragmento de floresta madura vizinho ao ensaio. Ambos localizados em Anhembi/SP (Estação Experimental de Anhembi/USP e Mata do Barreiro Rico). O tratamento usual consistiu em adubação de base e capina mecânica na linha de plantio até dois anos, e, o intensivo teve adubações complementares e capina química em área total até dois anos. Foram desenvolvidos modelos alométricos de estimativa da biomassa através de amostragem destrutiva de 80 árvores, sendo quatro indivíduos por espécie, selecionados por classes de área seccional. Determinaram-se massa seca e teor de C, para os compartimentos copa, lenho e raízes. Através das equações, do inventário ao sexto ano e dos teores de carbono, foram calculados os estoques de carbono por compartimento, nos dois tratamentos. Determinaram-se os estoques de carbono na biomassa herbácea, serapilheira e solo. Foi calculada a variação de carbono por compartimento nos dois tratamentos. Os estoques de carbono na floresta madura foram quantificados utilizando dados de 10 parcelas de inventário, aplicados em modelo alométrico adequado para Mata Atlântica. A densidade da madeira variou até 3 vezes entre espécies (0,22 a 0,70 gcm-3), o teor de C foi pouco variável (46,5%). Foram adequadamente ajustadas equações de biomassa lenhosa, raiz e copa com base na área seccional, altura e densidade da madeira. A porcentagem de raízes é expressiva (30%) na biomassa total, mas as espécies não pioneiras mostraram maior razão raiz:parte aérea (0,32) que as pioneiras (0,28). A silvicultura intensiva elevou o crescimento do compartimento lenhoso em 250% (1,85 para 6,45Mg ha-1ano-1), devido a maior eficiência da copa e alocação de C no tronco. O carbono no solo embora representativo, não propiciou seqüestro em 6 anos, dada alta variabilidade espacial. O tratamento intensivo obteve maior seqüestro de C, atingindo 4,22Mg C ha-1 ano-1 (64% no tronco e galhos, e 20% nas raízes). Os estoques de C no solo e serapilheira foram próximos entre o sistema intensivo de restauração e floresta madura, sendo os estoques no tronco, galhos e raízes, o diferencial entre os sistemas. Com base no crescimento médio das árvores e estoque de C nas restaurações até sexto ano (7 e 21kg árvore-1 e 5,2 e 18,2Mg C ha-1, respectivamente no sistema usual e intensivo), e no tamanho médio das árvores e estoque de C na floresta madura (204kg árvore-1 e 138Mg C ha-1) estimou-se cerca de 50 anos para o sistema intensivo atingir maturidade, embora haja necessidade de estudos relacionados à biodiversidade e sustentabilidade destes sistemas de restauração a longo prazo. / In order to study carbon sequestration in forest restoration systems and discuss its potential and barriers to the CDM forestry, this paper had two main objectives: i) quantify the initial rate of carbon sequestration in compartments aboveground, roots, soil and forest floor, on Atlantic forest restoration, with 20 native species (10 pioneers and 10 non pioneer), submitted to contrasting management conditions (usual and intensive), installed on Brachiaria decumbens pasture in 3 x 2 m spacing, and ii) comparing the carbon stocks of these two systems, observing the end of the sixth year of restoration, with values determined in a fragment of mature forest adjacent to the test. Both studies are located in Anhembi, São Paulo (USP Anhembi Experimental Station and the Barreiro Rico reserve). The usual treatment consisted of only fertilizer at planting and mechanical weeding only in the row up to two years, while the intensive treatment had additional fertilization beyond crop fertilization and chemical weed control also in the entire area until two years after planting. We developed allometric equations for estimating biomass through destructive sampling of 80 trees. Four individuals per species were selected based on classes of sectional area. Dry weight were determined and the carbon content for wood and roots. Through the equations, and carbon content we calculated carbon stocks per compartment, in both treatments. Carbon stocks in herbaceous, in the litter and soil were also determined. With these estimates we calculated the variation of carbon per compartment in the two restoration systems. Carbon stocks in mature forest were quantified using data from 10 permanent plots of inventory and applying appropriate allometric models. The wood density varied between species by up to 3 times (0.22 to 0.70 g cm-3) while the C content was relatively constant (46.5%). Appropriately adjusted equations for aboveground woody biomass, root and crown biomass were established using cross-sectional area, height and wood density. The percentage of roots is significant (30%) compared to the total, and non-pioneer species showed a higher ratio root / shoot (0.32) than the pioneer (0.28). The intensive forestry increased growth of woody compartment by 250% (1.85 to 6.45 Mg ha-1 yr-1), given the greater efficiency of the canopy and allocation of C to the trunk. The carbon content in the soil although representative in the total stock, did not result in C sequestration in the six years period, given its high spatial variability. The largest C sequestration was observed in the intensive treatment, reaching 4.22 Mg C ha-1 yr-1, 64% on the trunk and branches, and 20% in roots. The values of C stock in soil and litter were similar between the intensive system of forest restoration and mature forest, and indeed the trunk, branches and roots stocks, the major difference between the systems. Based on the average growth of trees and carbon stocks in the restoration and the first 6 years (7 and 21 kg tree-1 in the usual system and intensive, and 5.2 and 18.2 Mg C ha-1 in these same treatments), and the average tree size and carbon stocks in mature forest (204 kg tree-1 and 138 Mg C ha-1), a 50 years period was estimated for the intensive system to reach forest maturity although there is a need for studies relating biodiversity and sustainability of these restored systems in the long run.

Made available in DSpace on 2017-07-25T19:30:59Z (GMT). No. of bitstreams: 1 Joelcio E.pdf: 2686383 bytes, checksum: 4ea94bfca4c06a1d4a43d47175582d2a (MD5) Previous issue date: 2016-06-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Agriculture and generally livestock, the way in which they were driven from the green revolution walked deep-rooted form of externalities are these positive and / or negative,and in this context there is a need for improvement of applicable methodologies to map these, so this study aims to assess the dynamics of a unit of agricultural and livestock production temporally through emergy methodologies and inventory of greenhouse gases - GHGs. For the evaluation of proposed methodologies used a unit of agricultural and livestock production in the municipality of Carambei, state of Paraná, Brazil, and this computed data eleven years, starting in 2005 and ending in the year 2016 range this that makes up ten years of mainly agricultural production and a year with the entry of the livestock sector, this important dynamic in the time proposed comparison. By Emergy methodology sought to calculate besides the Transformity values (Tr), Renewability (%R), Income Ratio Emergy Net (EYR), Emergy Investment Ratio (EIR), Environmental load (ELR) and Sustainability Index (SI) and through the GHG inventory evaluation established that the calculations for the application of organic fertilizers, synthetic nitrogenous fertilizers, lime, urea, pesticides, also enteric fermentation, handling of animal waste (nitrous oxide and methane) , secondary sources of N2O (atmospheric deposition and leaching or runoff), crop residues, mechanized operations, electric power and combustion stationary. As the emergy methodology there was a major change of Tr values over the period studied reaching extreme values of 60276.40 sej.J-1 in year three to 121,255.08 sej.J-1 in the last year of study in However other values observed for% R,EYR, EIR, ELR and SI have not undergone substantial change, and generally behaved as regular, as the GHG observed an important dynamic of CO2 mitigation on the ground,starting from value of 13.76 t ha-1 at baseline to 39.15 Mg ha-1 in the last year survey, with special contribution of the livestock sector in this dynamic, as GHG emissions was observed that the entrance of livestock sector in the unit contributed decisively to a significant increase, especially influenced by the CH4 emission arising from enteric fermentation, however when computing the balance of CO2eq for the period studied there was no major change presenting minimum value of 4.93 MgCO2eq ha-1 in year four and a value of 6.75 MgCO2eq ha-1 in the last year of study, through the relationship established between the two methods was found to be an important change of the unit studied from the entrance to the livestock sector, the ratio Tr / CO2 balance showed minimum values 8.18 in the year seven to maximum 16.55 in the past year and the produced energy ratio (MJ) for the issuance of CO2eq (kg) showed 30.62 MJ values KgCO2eq-1 in year 2 to 8.97 MJ KgCO2eq-1 in the last year. In general it can be concluded that there was a negative change in the order of 65% for the system as a whole is subject to the emergy aspects and greenhouse gases listed after the entry of the livestock sector in the studied unit. / A agricultura e a pecuária de modo geral, da maneira em que foram impulsionadas a partir da revolução verde caminharam de forma extremamente arraigada de externalidades sejam estas positivas e/ou negativas. Neste contexto surge a necessidade de aprimoramento de metodologias aplicáveis ao mapeamento destas, assim o presente estudo visa avaliar a dinâmica de uma unidade de produção agrícola e pecuária temporalmente, através das metodologias emergética e de inventário da emissão de gases de efeito estufa - GEE. Para a avaliação das metodologias propostas utilizou-se uma unidade de produção agrícola e pecuária situada no município de Carambeí, estado do Paraná, Brasil, sendo nesta computado os dados de onze anos, iniciando no ano de 2005 e finalizando no ano de 2016, intervalo este que compõe dez anos de produção essencialmente agrícola e um ano com a entrada do setor pecuário, dinâmica importante para a comparação temporal proposta. Através da metodologia emergética buscou-se calcular os valores de: Transformidade (Tr), Renovabilidade (%R), Razão de Rendimento Emergético Líquido (EYR), Razão de Investimento de Emergia (EIR), Carga Ambiental (ELR) e Índice de Sustentabilidade (SI) e através da avaliação de inventário de GEE estabeleceu-se os cálculos referentes à aplicação de fertilizantes orgânicos, fertilizantes nitrogenados sintéticos, calcário, ureia, defensivos agrícolas, também da fermentação entérica, manejo de dejetos de animais (Óxido nitroso e Metano), fontes secundárias de N2O (deposição atmosférica e lixiviação ou escoamento superficial), resíduos de colheitas, operações mecanizadas, energia elétrica e combustão estacionária. Quanto a metodologia emergética observou-se uma importante alteração dos valores de Tr ao longo do período estudado atingindo valores extremos de 60.276,40 sej.J-1 no ano três a 121.255,08 sej.J-1 no último ano de estudo, em contrapartida os demais valores observados para %R, EYR, EIR, ELR e SI não sofreram alteração substancial, sendo que de maneira geral se comportaram como sendo regulares. Quanto aos GEE observou-se uma importante dinâmica de mitigação de CO2 no solo, partindo do valor de 13,76 Mg ha-1 no início do estudo para 39,15 Mg ha-1 no último ano de levantamento, com especial contribuição do setor pecuário nesta dinâmica. Observou-se ainda que na emissão de GEE a entrada do setor pecuário na unidade contribuiu de maneira decisiva para um aumento expressivo, em especial influenciado pela emissão de CH4 advindo da fermentação entérica, porém quando computado o saldo de CO2eq para o período estudado observou-se não haver grande alteração apresentando valor mínimo de 4,93 MgCO2eq ha-1 no ano quatro e valor de 6,75 MgCO2eq ha-1 no último ano de estudo. Através da relação estabelecida entre as duas metodologias constatou-se uma importante alteração da unidade estudada a partir da entrada do setor pecuário, a relação Tr/Saldo de CO2 apresentou valores mínimos de 8,18 no ano sete ao máximo de 16,55 no último ano e a relação de energia produzida (MJ) para a emissão de CO2eq (Kg) apresentou valores de 30,62 MJ KgCO2eq-1 no ano dois a 8,97 MJ KgCO2eq-1 no último ano. De maneira geral pode-se concluir que houve um alteração negativa na ordem de 65% para o sistema como um todo se observados os aspectos emergéticos e de gases de efeito estufa relacionados após a entrada do setor pecuário na unidade estudada.

O desmatamento da floresta amazônica tem causado preocupação na sociedade civil e científica mundial demandando pesquisas que busquem mitigar os impactos ambientais provocados por esse fenômeno. Esta tese tem como objetivo central analisar o uso dos sistemas agroflorestais à base de cacau como alternativa para recuperação de áreas degradadas pelo desmatamento da floresta Amazônica brasileira. Portanto, são aprestados três trabalhos que abordam essa temática. O primeiro estudo realiza uma pesquisa documental da produção científica na Amazônia brasileira sobre os sistemas agroflorestais com cacau (Theobroma cacao L.) buscando identificar os principais escopos nos quais essas pesquisas estão inseridas, assim como, subsidiar a prospecção de escopos complementares para futuras pesquisas. O segundo estudo analisa a utilização de sistemas agroflorestais à base de cacau como alternativa de cobertura vegetal sustentável para recuperação das áreas degradadas na Amazônia brasileira, assim como, compara os rendimentos de dois sistemas agroflorestais, um indicado pela pesquisa agropecuária e outro alternativo, implantado em área de produtor rural. Finalmente, o terceiro estudo analisa o crescimento e rendimento de madeira das plantas de mogno (Swietenia macrophylla King) utilizadas como sombreamento definitivo em sistemas agroflorestais à base de cacau implantadas em uma propriedade rural localizada no Estado do Pará, na Amazônia brasileira, em solos do tipo Terra Rocha Estruturada e Podzólico Vermelho Amarelo. Os resultados mostram que mais de 47 espécies vegetais de valor comercial nativas da região ou exóticas são contempladas nos diferentes sistemas agroflorestais à base de cacau cultivados na região. Os indicadores de rentabilidade obtidos dos dois sistemas analisados indicam que esses sistemas são viáveis financeiramente e podem ser financiados pelo programa oficial de crédito rural destinado a implantação de sistemas agroflorestais na Amazônia, o FNO-Biodiversidade, assim como, que as quantidades de carbono atmosférico sequestrada por esses sistemas se aproximam as das florestas nativas. E finalmente, que as plantas de mogno utilizadas como sombreamento nesses sistemas tiveram bom desenvolvimento em altura e diâmetro e o rendimento de madeira foi superior ao encontrado em condições naturais nas florestas da região. Esses resultados sugerem que os sistemas agroflorestais à base de cacau são uma alternativa econômica e ecologicamente sustentáveis para recompor a cobertura vegetal das áreas degradadas pelo desmatamento na Amazônia brasileira, além de proporcionar a mitigação dos danos ambientais provocados pelo desmatamento. / The deforestation of the Amazon rainforest has caused concern in civil society and global scientific research in fact demanding mitigate environmental impacts caused by this phenomenon. This thesis aims to analyze use of central agroforestry to cocoa as an alternative for recovery of degraded areas by deforestation of the Amazon rainforest in Brazil. So are three works that discuss this dressed. The first study performs a documentary research of the scientific production in the Brazilian Amazon on agroforestry systems with Cacao (Theobroma cacao l.) seeking to identify the main scopes in which these searches are included, as well as subsidizing the prospect for additional scopes for further research. The second study examines the use of agroforestry systems based on cocoa as an alternative sustainable vegetation cover for recovery of degraded areas in the Brazilian Amazon, as well as, compares the income of two agroforestry systems, an agricultural research and indicated another alternative, deployed in the area of rural producer. Finally, the third study examines the growth and yield of wood plants of mahogany (Swietenia macrophylla King) used as final shading in agroforestry cocoa base deployed in a country estate in the Pará State, in the Brazilian Amazon, in soils of the Earth type Structured Rock and Red Yellow Podzolic. The results show that over 47 species of plants native to the region or business value are considered exotic in different agroforestry systems based on cacao grown in the region. The profitability indicators obtained from two systems analyzed indicate that these systems are financially viable and can be financed by the program officer rural credit aimed at implementation of agroforestry systems in the Amazon, the FNO-biodiversity, as well as the amounts of atmospheric carbon sequestered by these systems approach the native forests. And finally, the plants of mahogany used as shading on these systems have had good development in height and diameter, and yield of wood was superior to that found in natural conditions in the forests of the region. These results suggest that the cocoa-based agroforestry systems are an economically and ecologically sustainable alternative to recompose the vegetal covering of areas degraded by deforestation in the Brazilian Amazon, in addition to providing the mitigation of environmental damage caused by deforestation.

O aumento das concentrações dos gases-estufa, principalmente o dióxido de carbono, e as mudanças climáticas se tornaram assuntos científico, econômico e político importantes nos últimos anos. O Mecanismo de Desenvolvimento Limpo, do Protocolo de Kyoto concede créditos de carbono comercializáveis para projetos que promovam o seqüestro de carbono nos países em desenvolvimento. Portanto, avaliar a capacidade de absorção de CO2 pela vegetação terrestre é um aspecto importante, o que justifica o interesse em desenvolver modelos de fluxo e troca desse gás em diferentes escalas. O desenvolvimento desses modelos é dificultado pela não-linearidade dos processos ecofisiológicos. Este trabalho apresenta um método de modelagem de fotossíntese no nível da folha, como um primeiro passo para um método de quantificação do potencial de seqüestro de carbono. A técnica utilizada foi a de redes neurais artificiais, uma vez que ela permite ajustar relações não lineares entre as variáveis de entrada e de saída. O trabalho foi divido em duas partes: fitomonitoração e modelagem. A fitomonitoração foi realizada em jatobá (Hymenaea courbaril), durante um ano. Medindo-se variáveis fisiológicas: taxa de fotossíntese, taxa de transpiração, condutância estomática, temperatura da folha, e fluorescência, e variáveis ambientais: concentração de CO2, radiação fotossintética ativa, umidade relativa e temperatura do ar. Uma quantidade de dados inédita para esse tipo de experimento e para essa espécie vegetal foi obtida. A análise dos resultados da fitomonitoração mostra características importantes sobre o comportamento das variáveis fisiológicas em plântulas de jatobá e das variáveis ambientais de seu entorno, casa de vegetação, nas quatro estações do ano. Os dados coletados foram utilizados para a modelagem da rede neural. Os treinamentos foram realizados com diferentes combinações de variáveis de entrada para observar qual era o conjunto de variáveis às quais a rede respondia melhor. A análise dos resultados dos treinamentos mostrou que com a técnica de redes neurais é possível atingir uma aproximação da função fotossíntese com 92% de acertos para entradas com dados filtrados. / The increases in greenhouse gas concentrations, mainly carbon dioxide, and the climatic changes have become important scientific, economic, and political subjects in the past years. The Kyoto Protocol establishes the Clean Development Mechanism, which grants carbon credits for projects that promote the sequestration of carbon in developing countries. Therefore, it is important to evaluate the CO2 absorption capacity by terrestrial plants, and this requires the development of gas flow and gas exchange models in different scales. That development is usually complicated, because the ecophysiological processes are non-linear. This work presents a method to model photosynthesis at the leaf level, as a first step toward quantifying the potential of carbon sequestration. The technique used was artificial neural networks (ANNs), as it allows the adjustment of non-linear relationships between input and output variables. The work was divided in two parts: phytomonitoring and modeling. The phytomonitoring was accomplished in jatoba (Hymenaea courbaril) during one year. The following physiologic variables were measured: photosynthesis rate, transpiration rate, stomatal conductance, leaf temperature, and fluorescence; and environmental variables: CO2 concentration, photosynthetic activity radiation, relative humidity, and air temperature. An unprecedented amount of data for that type of experiment and for that plant species was obtained. The analysis of these data showed important characteristics about the relationship of the physiologic variables in Hymenaea courbaril and the environmental variables, in the four seasons. The data collected were used for the modeling and fine-tuning of the neural network. The network was trained with different combinations of input variables to observe to which group of variables the neural network responded better. The analysis of the training results showed that with the ANN technique it is possible to achieve a very good approximation of the photosynthesis function, with 92% success rate for entries consisting of filtered data.