Deforestation of tropical forests is one of the most pressing environmental problems of the twenty-first century, leading to the loss of environmental services such as climate regulation and biodiversity. The expansion of the agricultural frontier by small landholder farmers continues to be one of the major drivers of land use change in the Amazon region. Much of the recent research in the Brazilian Amazon has been focused on modeling their behavior in order to prescribe policies that can curb current deforestation rates and promote more sustainable land use practices. The availability of more sophisticated remote sensing and economic modeling tools has led to the proliferation of agricultural household level models that attempt to explain land use change processes at the farm level. This dissertation tests the household life cycle theory in one of the oldest colonization fronts in the Brazilian Amazon: Rondônia, now a post-frontier. The study examines household and farm level changes over time for specific aspects of the frontier process that can be tested using the household life cycle theory. This study introduces important additions to the life cycle theory in order to consider the more dynamic and complex set of factors that characterize modern frontier processes. Specifically the study examines: (1) property fragmentation and expansion processes, (2) property ownership, turnover and change, and (3) land use change processes at the property level. These are linked to changes in the social and economic features of the smallholder farmer as it moves along its life cycle. The central hypothesis is that these changes in property and land use dynamics can be explained by the corresponding changes in the life cycle of the household as the frontier evolves over time into a post-frontier. It was found that the household life cycle theory did not adequately explain land use change processes over time. As the frontier evolved into the modern post-frontier, the labor and drudgery constraints associated with the initial frontier processes, as exemplified in the household life cycle theory, became less relevant. The Sauerian concept of cultural successions and the concept of scale from hierarchical ecology are used in order to explain the apparent inconsistencies found between the household life cycle theory and land use change processes over time and at different scales of analysis. The household life cycle theory is a useful theoretical framework from which to examine the effects of household level factors on land use; however, this must be embedded within concepts of time and scale that determine their differentiated impact and behavior. Existing plans to expand road infrastructure into the Amazon region will open-up previously inaccessible rainforest regions to agricultural frontier expansion at a scale unprecedented since the mid-eighties. Findings from this study reveal that policies based on household life cycle postulates will have limited impacts in reducing deforestation rates and promoting sustainable land use practices. Appropriate accounting of the social and environmental costs of future infrastructure development projects should consider associated frontier agricultural expansion costs to discourage further deforestation. / Ph. D.

Fuel wood cutting, collection and distribution in recent years have been one of the booming industries in Nigeria. Plagued with the problem of energy for domestic use, more than two third of Nigerians residing in the rural areas wholly depend on fuel wood energy for their household activities; cooking, heating and generation of warmth. A consumption put at  43 million metric tons, (43 x 109 kg) per annum giving a per capita consumption of about 511.2 kg / person per anum for rural dwellers and 360 kg / person for urban settlers. An enormous use of fuel wood at this large scale poses a grave and devastating environmental side effect, notably being deforestation and desertification now eating deep into the heart of Nigerian Forest cover at a very alarming rate. (Bugaje 2004). Akinbami et al 2001’s assessment has identified feed stock substitute for an economically feasible biogas programme, a substitute for wood fuel, and Nigeria produces 227,500 tons (2.275 x 108 kg ) of fresh animal wastes daily. According to the study, 1 kilogram (kg) of fresh animal waste produces about 0.03 m3 gas, hence, Nigeria can produce about 6.8 million m3 of biogas everyday, enough to meet the cooking need of an average family size, an annual equivalent put at 4.81 million barrels crude oil, or 6.9 x 106 tons of fuel wood (Adeoti et al, 2001). This work is aimed at Evaluating Using Quantitative and Comparative Data analysis, a Batch System, Small Scale family size bio digester; The possible volume of gas that could be produced as against the same quantity of wood consumed, the estimated amount of fuel wood in kg that could be avoided, and the forested land that could be conserved by the substitution.   From the result obtained, the conservable fuel wood for a family size of say 7 could range from 11.524 kg/day when substituted with the equivalent quantity of gas (2.3048 m3), while CO2 avoidable from tree felling in the chosen region could range close to 1,540,000kg (1,540 metric tons per annum). / <p>2008-10-09</p>

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<p> This study reports on karren forms on limestone dip slopes, which were recently exposed by deforestation on the Quatsino Formation and observable relationships of the karren features of a specific sl~pe are represented as a detailed map. Also, many relationships of gravitomorphic runnel characteristics are analyzed for significance. Runnel types being considered are Hortonian, decantation and composite forms. Solution runnel width, depth and width/depth ratio are studied in association with length. These relationships determine whether the runnel types conform to a theoretical model. Typical aeas·ares of the karren in this area were also recorded. Composite forms are the most abundant because Hortonian and decantation runnels amalgamate beyond about 3m to form composites. All the runnel types, excluding the decanters, illustrate the perfect minimum friction open-channel cross-section. </p> / Thesis / Bachelor of Arts (BA)

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.

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Many regions of the Amazon are experiencing drastic changes as deforestation and climate change drive the world’s largest continuous rainforest towards a ‘tipping point’. These disturbances are changing natural cycles that once past a critical threshold, will mark an unstoppable transition to an altered ecosystem. Losing areas of the Amazon rainforest will have implications for the global climate, global carbon budget, and global hydrological regimes. Scholars have projected these tipping points for areas of the eastern Amazon rainforest, but much less scholarship focuses on the headwaters of the Western Amazon, an area of great cultural and biological importance. Ecuador is one such country. This study aims to model a tipping point for the Ecuadorian Amazon by investigating the potential outcomes of a warming climate and land cover change through 1. a comprehensive review of regional circulation models and global circulation models in the Ecuadorian Amazon, 2. a comprehensive review of anthropogenic disturbances in the Ecuadorian Amazon and their impact on communities, soil, flora and fauna, and 3. A model projecting the deforestation tipping point of the Ecuadorian Amazon. The results of my study will identify patterns of forest loss and provide quantitative assessments of potential ‘tipping points’ in a future Ecuadorian Amazon. The methods and model created herein can be used by future researchers to evaluate regional drivers of deforestation and predict land cover change under future scenarios.