Photocopy of typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1978. / Bibliography: leaves [295]-303. / Microfiche. / xiii, 303 leaves ill. (some col.), map. 28 cm

O sistema agrícola itinerante (SAI), uma das formas mais antigas de agricultura, continua sendo praticado pelas comunidades quilombolas do Vale do Ribeira-SP. Entretanto, as atuais restrições da legislação ambiental brasileira, a maior integração ao mercado, e a influência de instituições e políticas públicas, estão entre os principais motivos da diminuição desta prática. A produção para o consumo doméstico do SAI está sendo substituída pela agricultura permanente e comercial de pupunheira para palmito, apoiada por incentivos governamentais como créditos financeiros e assistência técnica especializada. Este projeto teve como objetivo avaliar a produtividade entre os diferentes sistemas de cultivo e entre áreas submetidas a diferentes tempos de pousio, discutindo os motivos e os impactos desta transição, sua sustentabilidade, assim como os impactos econômicos para as comunidades. Utilizamos a unidade doméstica como unidade de análise para a organização social do trabalho; para cada atividade reconstituímos o itinerário técnico através de entrevistas semiestruturadas e visitas a campo; e para estimar a capacidade de remuneração dos diferentes sistemas agrícolas utilizamos o cálculo do valor agregado líquido. Durante onze meses acompanhamos a implantação das roças para consumo doméstico e o manejo do cultivo permanente de pupunheira para palmito. Os resultados mostram que há uma tendência de que em capoeiras mais jovens (entre 10-15 anos de pousio) o tempo destinado ao trabalho seja menor quando comparado com o tempo destinado ao trabalho em capoeiras avançadas (com mais de 25 anos de pousio). Entretanto, devido ao tamanho reduzido da amostra não foi possível testar sua significância. Já para a avaliação da produtividade entre os diferentes sistemas, a agricultura permanente se mostrou mais eficiente em termos de renda e no uso do trabalho, do que o SAI. Entretanto, ao considerarmos a multifuncionalidade da agricultura, o SAI desempenha um papel não só de produção de alimentos e fibras, mas também é parte de um complexo de relações socioambientais que incluem a manutenção da diversidade cultural, da agrobiodiversidade e da preservação ambiental. / The shifting cultivation system (SCS), one of the oldest forms of agriculture, is still practiced by quilombola communities in the Vale do Ribeira - SP. However, current restrictions of the Brazilian environmental legislation, increased market integration, and the influence of institutions and public policies, are among the main reasons for the decrease in this practice. The production of SCS for domestic consumption is being replaced by permanent and commercial cultivation of peach palm, supported by government incentives such as financial claims and specialized technical assistance. This project aimed to assess the productivity of the different cultivation systems and between areas under different fallow lenghts, discussing the reasons and the impacts of this transition, its sustainability and economic impacts for communities. The household was used as the unit of analysis for social work organization; for each activity we recomposed the technical itinerary through semi-structured interviews and field visits; to estimate the remuneration capacity of the different farming systems used the added net value. During eleven months we monitored the implementation of the cultivated fields for domestic consumption and the management of permanent cultivation of peach palm. Our results showa tendency for lower worktime in fields with younger fallows (10-15 years) when compared to older ones (25 years).However, due to the small sample size after the abandonment of the fields by some farmers it was not possible to test its significance. As for the evaluation of productivity between the two different systems, permanent agriculture was more efficient in terms of income and the use of labor than SCS. However, when the multifunctionality of agriculture is considered, SCS plays a role not only in food and fiber production, but is also part of a complex socio-environmental relations that include the maintenance of cultural diversity, agrobiodiversity and environmental preservation.

No description available.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第20816号 / 農博第2256号 / 新制||農||1055(附属図書館) / 学位論文||H30||N5098(農学部図書室) / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 神﨑 護, 教授 北島 薫, 教授 德地 直子 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

Forest degradation is a significant yet underestimated source of carbon emissions. Traditionally, monitoring forest degradation has been difficult due to a lack of sufficiently frequent satellite observations and reliable analysis methods. Recent advancements in satellite remote sensing provide new opportunities to monitor, attribute and analyze forest degradation. This dissertation develops methods to monitor and attribute forest degradation and analyzes the spatial-temporal patterns of forest degradation and associated carbon emissions. A new method, Continuous Change Detection and Classification - Spectral Mixture Analysis (CCDC-SMA), was developed on Google Earth Engine (GEE) to monitor abrupt and gradual forest degradation in temperate climate zones using Landsat time series. CCDC-SMA was applied to the Republic of Georgia from 1987-2019. Results show that forest degradation affected a much larger area than deforestation. In addition, CCDC-SMA was extended to monitor forest degradation in the tropics and applied in Laos. Attribution of the drivers of forest degradation was based on a combination of CCDC-SMA results, post-disturbance land cover classification and object-based image analysis. Shifting cultivation is the largest kind of forest disturbance in Laos, affecting 32.9% ± 1.9% of Laos during 1991-2020. The results show that shifting cultivation has been expanding and intensifying in Laos, especially in the last five years. Furthermore, the length of fallow periods has been continuously declining, which indicates that shifting cultivation is becoming increasingly unsustainable. Combining biomass estimates from the Global Ecosystem Dynamics Investigation (GEDI) and area estimates of shifting cultivation, the net carbon emissions from shifting cultivation during 1991-2020 in Laos are 1.28 ± 0.12 petagrams of CO2 equivalent (Pg CO2 eq). Tree canopy height and aboveground biomass density are strongly correlated with the years of regrowth since the latest year of slash-and-burn activities, which can be expressed using logarithmic models. It takes 131 years for the biomass to recover to pre-disturbed levels based on the logarithmic models. In addition to advancements in remote sensing of forest degradation, the results of this dissertation provide valuable information for policy related to forest management and reduction of carbon emissions.

"Slash-and-burn" agriculture, or shifting cultivation, is perceived by many to be the leading cause of land degradation in tropical forests. Performed mainly by resource-poor farmers, shifting cultivation is the most widespread form of agriculture in the tropics. Concern over its environmental impacts has led to calls throughout the twentieth century for alternatives by policy-makers and development planners. This study employs a constructivist framework, post-colonial perspectives, and rhetorical methods to understand the images which support such assertions regarding shifting cultivation, primarily in policy-oriented depictions. Elements of Kenneth Burke's "dramatistic" method are used, including the analysis of hierarchies which structure discourse, and pentadic analysis. / Ph. D.

Researchers recognize the need to better understand the factors influencing indigenous land use in order to design sustainable tropical forest management programs. A key relationship that has been long overlooked in peasant societies is the one between communal labor access through social networks and land acquisition/accumulation. This study examines land distribution and labor patterns in traditional agriculture of a lowland and a upland community on the Maranon River near Iquitos, Peru. Data were gathered through household interviews (n=76) and field visits (n=396) between June and November 2001. Results reveal marked variations in access to land and communal labor between and within communities. Household age, initial land wealth and initial inputs of labor are crucial in explaining land and labor inequalities within villages. This research contributes to a better understanding of the factors that give rise to local heterogeneity in wealth holdings and livelihood strategies, necessary tools to promote conservation throughout the region and beyond.

No description available.

Fires are the primary method of deforestation and agricultural management in the tropics, but associated emissions such as aerosols, ozone, and carbon monoxide can have negative impacts on ecosystems, climate, and public health. Recent advances in satellite monitoring of fire activity, including using thermal anomalies for active fire detections and burn scar mapping of post-fire effects, have offered an unprecedented level of detail in understanding the magnitude and extent of fire activity. This dissertation aims to quantify the human health impact across populations in tropical regions by determining which areas are the most susceptible to transported fire emissions and how this exposure varies over time. The following chapters can be used to highlight critical conservation regions, not only for conserving ecosystems for biodiversity and climate benefits, but also for protecting public health. To address how fire emissions can affect regional populations, satellite observations of fire activity are combined with models of how tropical fire emissions are transported in the atmosphere. Satellites provide two primary pieces of information for this approach: 1) measurements of the distribution and magnitude of fire activity, and 2) categorization of fire types (such as agricultural burning or deforestation) by overlaying observed fire patterns on land use maps. Atmospheric models perform the crucial step of simulating how emissions evolve and where they are transported after release into the atmosphere. The following dissertation chapters are linked through exploration of fire emissions impacts from continental to local scales, including implementing fire emissions inventories into atmospheric models, quantifying population exposure to fire activity in Equatorial Asia, and projecting fire emissions associated with various future land use scenarios in Sumatra. Model estimates of aerosol concentrations are more influenced than trace gases by using finer temporal resolution fire emissions, due to interactions between emissions and modeled meteorology and transport. This in turn can impact air quality estimates by permitting higher peak concentrations. In addition, model results show that population exposure to fire emissions in Equatorial Asia is highly variable over time depending on the phase of the El Niño cycle; strong El Niño years can have fire contributions to fine particulate matter of up to 200 µg/m³ near fire sources, corresponding to 200 additional days per year over the World Health Organization 50 µg/m³ 24-hour fine particulate matter air quality target. These risks are not confined to people living near fire sources, but expose broad regional populations due to the atmospheric transport of emissions. Health impacts also depend on underlying fuel characteristics, with the future magnitude of Equatorial Asian fire emissions estimated to be strongly dependent on the level of protection given to fuel-rich peatswamp forests (contributing 33-48% of future emissions in the absence of protection). Collectively, these chapters emphasize variability in how tropical fire emissions affect regional population exposures to outdoor air pollution, and the need to consider the dependence of this public health effect on different fuel types and year-to-year variations in climate. The results described in this dissertation quantify direct benefits of conservation for people living near fire areas.

Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2014-10-14T14:46:29Z No. of bitstreams: 2 Tese - Idelfonso Colares de Freitas - Agronomia.pdf: 1658368 bytes, checksum: 281951adbbc39fb163075382c1dc3798 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2014-10-17T21:40:37Z (GMT) No. of bitstreams: 2 Tese - Idelfonso Colares de Freitas - Agronomia.pdf: 1658368 bytes, checksum: 281951adbbc39fb163075382c1dc3798 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-10-17T21:40:37Z (GMT). No. of bitstreams: 2 Tese - Idelfonso Colares de Freitas - Agronomia.pdf: 1658368 bytes, checksum: 281951adbbc39fb163075382c1dc3798 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-06-10 / Based on the premise that the replacement of native forests by agroecosystems impacts the soil, were studied different forms of soil use compared to a fragment preserved forest. The study was conducted in an Entisol Quartzipsammentunder the family agriculture use for 22 years, managed under: SAF – Agroforestry system, PA - Pasture, RT - Slash and burn field and MA - Preserved forest. The management impacts on the soil were estimated by the changes in the accumulation and quality of the soil mulch and by the changes on the physical and chemical indicators of soil. The collect of soil mulch, the soil resistance to penetration, until 40 cm depth, and the collect of deformed and undeformed soil samples, for of physical and chemical analyzes, collected in seven repetitions for each system, layers 0-5, 5-10, 10-20 and 20-40 cm depths for two consecutive years and in two sampling periods (July 2010/2011 and January 2011/2012). The variables analyzed were: accumulation of soil mulch and its nutrient content, carbon stock on soil mulch and the soil, plant residue quality index, soil organic matter, soil acidity, exchangeable bases, cation exchange capacity, bases and aluminum saturation, strength penetration, bulk density, porosity and soil aggregation. The results showed that soil use with agroforestry system, even after 22 years of use, little differentiates itself from the preserved area. The conversion of forest in agroecosystems enhances the soil chemical properties and significantly reduces the stocked carbon in the soil mulch compartment, as noted in the “slash and burn” field. The soil use with pasture for successive years increases bulk density, strength penetration, microporosity and reduces soil macroporosity. In this study, clear distinctions between the forms of use and soil management were observed in stocks of litter on the soil surface and strength penetration. / Partindo da premissa que a substituição das florestas nativas por agroecossistemas impacta os solos, foram estudadas diferentes formas de uso do solo em comparação a um fragmento de floresta preservada. O estudo foi realizado em um Neossolo Quartzarênico sob uso da agricultura familiar por 22 anos, manejado sob: SAF – Sistema agroflorestal, PA – Pasto, RT – Roça de toco e MA – Mata preservada. Os impactos do manejo sobre o solo foram estimados por meio das mudanças ocorridas no acúmulo e qualidade da serrapilheira, indicadores físicos e químicos do solo. Coletas de serrapilheira, penetrometrias até 40 cm e amostras deformadas e indeformadas de solo, para fins de análises físicas e químicas, foram feitas em sete repetições por sistema de uso, nas camadas 0-5, 5-10, 10-20 e 20-40 cm, por dois anos consecutivos e em dois períodos de amostragem (Julho 2010/2011 e Janeiro 2011/2012). As variáveis analisadas foram: acúmulo de serrapilheira, teores de nutrientes na serrapilheira, estoque de carbono nos compartimentos serrapilheira e solo, índice de qualidade de resíduo vegetal, matéria orgânica do solo, acidez do solo, bases trocáveis, capacidade de troca de cátions, saturação por bases e alumínio, resistência do solo à penetração, densidade do solo, porosidade e agregação do solo. Os resultados apontaram que o uso do solo com sistema agroflorestal, mesmo após 22 anos de uso, pouco se diferencia da área preservada. A conversão da floresta em agroecossistemas potencializa os atributos químicos do solo e reduz, sensivelmente, o carbono estocado no compartimento serrapilheira, conforme observado na Roça de toco. O uso do solo com Pasto, por sucessivos anos, incrementa a densidade do solo, resistência à penetração do solo, microporosidade e reduz a macroporosidade do solo. Neste estudo, clara distinção entre as formas de uso e manejo do solo foram observadas nos estoques de serrapilheira sobre a superfície do solo e resistência à penetração.