The steeplands of Central America are being systematically deforested as population pressure dictates a need for an increase in subsistence agriculture. The combined effect of high rainfall and lack of conservation measures leads to high levels of soil erosion. In order to assess sustainable soil conservation technology, research was conducted in the mountainous agricultural area of Guinope, Honduras. Runoff and soil loss from a number of plots that were established on various ground slopes and under different land uses were measured during the 1994 and 1995 seasons. Natural and fired woodland were assessed to provide an indication of both baseline conditions and those associated with the initial stage of deforestation. Against these, the impacts of agriculture involving maize - Zea mays L.- with and without two leguminous cover crops - Mucuna sp. and Canavalia ensiformis (l)DC. - were assessed on ground sloping at 6, 11 and 18 degrees. Seasonal runoff under natural pine forest is shown to be 10 % that of maize agriculture on similar slopes while fired forest is 49 %. Of the cover crops, after a second year Mucuna is the most protective when intercropped with maize, giving runoff on 18 degree slopes which is 47 % that of maize grown by itself, compared with 51 % for Canavalia. On 11 degree slopes, Canavalia offers greater protection but here the difference between the two cover crops is marginal Soil erosion can be shown to be a function of ground slope. For maize grown by itself, soil losses from 6 and 11degree slopes are 13 % and 23 % those from 18 degree slopes. On two years of research Canavalia is more stable in giving protection. On 18 degree slopes, soil loss where Mucuna is intercropped is 43 % that under maize alone while for Canavalia it is 47 %. By comparison, the natural forest loses much less than 1 % that of the maize fields. This study clearly shows the vulnerability of steep lands that are being clear-felled. It also demonstrates the considerable advantages of using extensive green soil conservation technology in reducing soil erosion and prolonging the usefulness of land. This extends to relieving the pressure on virgin forest in a situation where population growth discourages long periods fallow as part of a form of shifting cultivation.

Monitoring large forest areas is presently feasible with satellite remote sensing as opposed to time-consuming and expensive ground surveys as alternative. This study evaluated, for the first time, the potential of using freely available medium resolution (30 m) Landsat time series data for deforestation monitoring in tropical rainforests of Kalimantan, Indonesia, at sub-annual time scales. A simple, generic, data-driven algorithm for deforestation detection based on a consecutive anomalies criterion was proposed. An accuracy assessment in the spatial and the temporal domain was carried out using high-confidence reference sample pixels interpreted with the aid of multi-temporal very high spatial resolution image series. Results showed a promising spatial accuracy, when three consecutive anomalies were required to confirm a deforestation event. Recommendations in tuning the algorithm for different operational use cases were provided within the context of satisfying REDD+ requirements, depending on whether spatial accuracy or temporal accuracy need to be optimized.

Monitoring large forest areas is presently feasible with satellite remote sensing as opposed to time-consuming and expensive ground surveys as alternative. This study evaluated, for the first time, the potential of using freely available medium resolution (30 m) Landsat time series data for deforestation monitoring in tropical rainforests of Kalimantan, Indonesia, at sub-annual time scales. A simple, generic, data-driven algorithm for deforestation detection based on a consecutive anomalies criterion was proposed. An accuracy assessment in the spatial and the temporal domain was carried out using high-confidence reference sample pixels interpreted with the aid of multi-temporal very high spatial resolution image series. Results showed a promising spatial accuracy, when three consecutive anomalies were required to confirm a deforestation event. Recommendations in tuning the algorithm for different operational use cases were provided within the context of satisfying REDD+ requirements, depending on whether spatial accuracy or temporal accuracy need to be optimized.

This dissertation analyses the impact of political and macroeconomic uncertainties on environmental outcomes and design of policy instruments.  The first essay examines how the rate of agricultural land expansion in tropical countries depends on the nature and persistence of new political regimes.  We use a novel panel data method that extends previous studies.  We find that both new autocratic and democratic regimes have accelerated the expansion of agricultural land, thus yielding support to some of the findings in the earlier literature.  Interesting differences emerge between regions, with the impact being most pronounced in Latin America.  The analysis is developed more formally using a simple competitive land use model with political regime dependent confiscation risk and agricultural subsidy policy.  The second essay evaluates the effectiveness of performance bonding for tropical forest concession management in achieving first and second best outcomes concerning reduced impact logging (RIL) standards.  As a novel contribution, this essay introduces a simple model of two-stage concession design, and focus on the impact of three complications: harvester participation constraints, government repayment risk, and imperfect enforcement.  We find several new and interesting results, in particular, imperfect enforcement and bond risk may deter implementation of bonding schemes as either the bond payment has to be set higher or the penalty mapping has to become more punitive.  Policy implications, including potential for mechanisms such as REDD+ in improving the bonding outcomes, and the degree of financial support required to guarantee full implementation of RIL, are also examined.  The third essay focuses on the relative performance of fixed versus intensity allowances in the presence of both productivity and energy price uncertainties.  Both allowance instruments achieve the same steady-state emissions reduction target of 20%, which is similar to the current policy proposals, and the regulator then chooses the allowance policy that has the lowest expected abatement cost.  We use a standard real business cycle (RBC) model to solve for the expected abatement cost under both policies.  Unlike previous studies, our results show that under a reasonable model calibration, fixed allowances outperform intensity allowances with as much as 30% cost difference. / Ph. D.

Fast and accurate monitoring of tropical forest disturbance is essential for understanding current patterns of deforestation as well as helping eliminate illegal logging. This dissertation explores the use of data from different satellites for near real-time monitoring of forest disturbance in tropical forests, including: development of new monitoring methods; development of new assessment methods; and assessment of the performance and operational readiness of existing methods. Current methods for accuracy assessment of remote sensing products do not address the priority of near real-time monitoring of detecting disturbance events as early as possible. I introduce a new assessment framework for near real-time products that focuses on the timing and the minimum detectable size of disturbance events. The new framework reveals the relationship between change detection accuracy and the time needed to identify events. In regions that are frequently cloudy, near real-time monitoring using data from a single sensor is difficult. This study extends the work by Xin et al. (2013) and develops a new time series method (Fusion2) based on fusion of Landsat and MODIS (Moderate Resolution Imaging Spectroradiometer) data. Results of three test sites in the Amazon Basin show that Fusion2 can detect 44.4% of the forest disturbance within 13 clear observations (82 days) after the initial disturbance. The smallest event detected by Fusion2 is 6.5 ha. Also, Fusion2 detects disturbance faster and has less commission error than more conventional methods. In a comparison of coarse resolution sensors, MODIS Terra and Aqua combined provides faster and more accurate detection of disturbance events than VIIRS (Visible Infrared Imaging Radiometer Suite) and MODIS single sensor data. The performance of near real-time monitoring using VIIRS is slightly worse than MODIS Terra but significantly better than MODIS Aqua. New monitoring methods developed in this dissertation provide forest protection organizations the capacity to monitor illegal logging events promptly. In the future, combining two Landsat and two Sentinel-2 satellites will provide global coverage at 30 m resolution every 4 days, and routine monitoring may be possible at high resolution. The methods and assessment framework developed in this dissertation are adaptable to newly available datasets.

No description available.

Em toda a superfície terrestre o uso humano está transformando grande parte das florestas, especialmente na região tropical. O desmatamento de florestas tropicais é uma das principais fontes de emissão de gases do efeito estufa e a principal ameaça à conservação de espécies e dos serviços ambientais prestados pela floresta. Dentro desse contexto que também envolve a fragmentação do habitat, o objetivo desse trabalho foi analisar como as relações entre a dinâmica do uso e cobertura da terra afetaram a estrutura e composição da comunidade de vertebrados, e também a qualidade da água em riachos no Sudoeste da Amazônia brasileira. Nós analisamos esse processo em uma área de aproximadamente 50000 km² por meio de mapas classificados a partir de imagens de satélite ao longo de 36 anos de monitoramento. Nós observamos uma perda de floresta da ordem de 24826 km² relacionada, dentre outros fatores, à expansão da malha viária de 3158 km para 12863 km de extensão, tornando a área de estudo como uma das mais desmatadas de toda a Amazônia brasileira. A dinâmica do uso e cobertura da terra ao longo da série temporal mostra que as paisagens com desmatamento mais recente apresentaram fragmentação mais intensa do que aquelas com desmatamento mais antigo e onde ocorreu pequena ou nenhuma derrubada de floresta. Os resultados da inferência com modelos generalizados de mínimos quadrados mostram que a proximidade das estradas é um dos fatores que contribuem para o aumento no desmatamento, principalmente em áreas com menor declividade e distantes dos rios. Os modelos lineares generalizados com os maiores valores de importância relativa para explicar a riqueza de espécies, biomassa agregada e o índice de vulnerabilidade à caça foram compostos pela área, número e distância entre os fragmentos como variáveis independentes. A área de floresta é importante também para a conservação da água, principalmente quanto à sua proporção na faixa de 100 m ao longo dos riachos amostrados. Levando-se em conta as características dos solos predominantes na microbacias e a sazonalidade, principalmente nos meses chuvosos, a redução de floresta próxima aos rios é responsável pelo aumento nas concentrações de alumínio, fosfato, sedimentos em suspensão, amônio e nitrato, de acordo com nossos modelos lineares generalizados. Ao final, considerações foram feitas a respeito do aumento da fiscalização e da regularização fundiária para impedir que a fronteira do desmatamento continue a avançar sobre áreas de floresta primária, e que o manejo das áreas fragmentadas inclua a restauração da floresta, principalmente ao longo dos rios para diminuir o isolamento dos fragmentos remanescentes. Nós ressaltamos também, a necessidade de se estudar como as perturbações recorrentes nos fragmentos como corte seletivo e incêndios continuam afetando a comunidade de vertebrados que ocorrem fora das áreas contínuas de floresta. / Extensive areas across the Earth surface have been modified by human land uses, particularly in the tropical region. Deforestation is one of main sources of emissions of greenhouse gases and the main threat to the conservation of biodiversity and ecosystem services provided by tropical forests. In the context of human-modified landscapes, including forest fragmentation, the main goal of this work is to understand the relationships between land use and land cover dynamics and the changes in the structure and composition of forest vertebrate community and also, the alterations in the quality of surface water in catchments. We assess land use dynamics about 50,000 km² of study area located in Southwestern Brazilian Amazon. By mean of maps of land cover classified from satellite images based in a 36-year monitoring, we observed a forest loss of 24,826 km² related to the expansion of road network from 3158 km to 12863 km in the same period. This result makes the study area as the most deforested of entire Brazilian Amazon. The land use dynamics show that fragmentation is higher in recent deforestation frontier than in both older deforestation and landscapes with few or no deforestation detected. Our results from inference with generalized least square models show that distance to the roads affects negatively the deforestation rates, mainly in flat areas and near to small and large rivers. The generalized linear models with higher relative importance to explain the species richness, aggregate biomass and the index of hunting vulnerability had as predictors the fragment area, number of patches and distance between fragments as major attributes of the landscape that affects the vertebrate community. The forest is important for maintenance of stream water quality, particularly if there is forest cover in the 100 m strips alongside the streams, considering the soil characteristics such as proportion of bases and seasonality. In our GLM multi-model analysis, the higher proportion of forest in surroundings the streams contributes to the increasing of concentrations in the rainy season of aluminum, phosphate, suspension sediments, ammonium and nitrate. At the end, we made consideration about law enforcement and landownership, to preclude the deforestation toward extensive areas of pristine forest. Moreover, we suggest that in fragmented landscapes the conservation efforts to be concentrated in forest restoration, mainly near to rivers, to reduce the isolation of the fragments. We highlighted the importance in monitoring the biodiversity responses to recurrent disturbing sources such as selective logging and accidental forest fires in fragmented landscapes.

Changes in land use and land cover are associated with many environmental issues observed on the earth’s surface. In the last decades, these changes were unprece-dented, mainly in tropical forest areas. The Brazilian Amazon, the world’s largest tropical forest, lost around 200.000 km² of primary forest in the last ten years (INPE, 2005). Considering this, and the consequences caused by this deforestation, it is important to know and define correctly the responsible agents, aiming at better pub-lic policies that can help preserve the forest. Searching for indicators that could help to identify the deforestation agents, some studies, such as Mertens and Lambin (1997), suggest that every deforestation process shapes the forest land in a specific way, producing a spatial pattern that can be interpreted as indicative of the agents with specific economic activities. Based on this hypothesis, the objective of this study was to contribute to a better understanding of land change processes in the Amazon forest, investigating the linkages between spatial patterns of deforestation, as visualized in satellite images, and different agents and their specific economic activities. To reach this objective, our methodological approach was based on socio-economic data acquired at a household level combined with data from satellite im-ages. First, different spatial patterns of deforestation were identified on the satellite images, based on the typologies proposed by Husson et al. (1995). Then, some of the identified spatial patterns were isolated and analyzed for specific aspects, such as, the deforestation rate calculated through satellite images. socio-economic character-istics based on household survey data and evolution of land use and land cover based on thematic maps derived from satellite images. In addition, cluster analysis was applied using the socio-economic data (household survey) and land use and land cover data (satellite images) in a search for homogeneous groups related to the spa-tial pattern. In the end, an Analysis of Variance (ANOVA) was applied to confirm the differences between spatial patterns. The results suggested that the different spatial patterns of deforestation found in the study area can be related to specific economic activities. Nevertheless, the re-sults have indicated that the spatial configuration is not a consequence of its main economic activity. They suggest that the spatial configuration is linked to the settle-ment project, and the main economic activity in the spatial patterns is a consequence of a set of factors such as: size of property, location and disposition of the property, presence or absence of infrastructure (road, market, transportation, economic and technical).

Em toda a superfície terrestre o uso humano está transformando grande parte das florestas, especialmente na região tropical. O desmatamento de florestas tropicais é uma das principais fontes de emissão de gases do efeito estufa e a principal ameaça à conservação de espécies e dos serviços ambientais prestados pela floresta. Dentro desse contexto que também envolve a fragmentação do habitat, o objetivo desse trabalho foi analisar como as relações entre a dinâmica do uso e cobertura da terra afetaram a estrutura e composição da comunidade de vertebrados, e também a qualidade da água em riachos no Sudoeste da Amazônia brasileira. Nós analisamos esse processo em uma área de aproximadamente 50000 km² por meio de mapas classificados a partir de imagens de satélite ao longo de 36 anos de monitoramento. Nós observamos uma perda de floresta da ordem de 24826 km² relacionada, dentre outros fatores, à expansão da malha viária de 3158 km para 12863 km de extensão, tornando a área de estudo como uma das mais desmatadas de toda a Amazônia brasileira. A dinâmica do uso e cobertura da terra ao longo da série temporal mostra que as paisagens com desmatamento mais recente apresentaram fragmentação mais intensa do que aquelas com desmatamento mais antigo e onde ocorreu pequena ou nenhuma derrubada de floresta. Os resultados da inferência com modelos generalizados de mínimos quadrados mostram que a proximidade das estradas é um dos fatores que contribuem para o aumento no desmatamento, principalmente em áreas com menor declividade e distantes dos rios. Os modelos lineares generalizados com os maiores valores de importância relativa para explicar a riqueza de espécies, biomassa agregada e o índice de vulnerabilidade à caça foram compostos pela área, número e distância entre os fragmentos como variáveis independentes. A área de floresta é importante também para a conservação da água, principalmente quanto à sua proporção na faixa de 100 m ao longo dos riachos amostrados. Levando-se em conta as características dos solos predominantes na microbacias e a sazonalidade, principalmente nos meses chuvosos, a redução de floresta próxima aos rios é responsável pelo aumento nas concentrações de alumínio, fosfato, sedimentos em suspensão, amônio e nitrato, de acordo com nossos modelos lineares generalizados. Ao final, considerações foram feitas a respeito do aumento da fiscalização e da regularização fundiária para impedir que a fronteira do desmatamento continue a avançar sobre áreas de floresta primária, e que o manejo das áreas fragmentadas inclua a restauração da floresta, principalmente ao longo dos rios para diminuir o isolamento dos fragmentos remanescentes. Nós ressaltamos também, a necessidade de se estudar como as perturbações recorrentes nos fragmentos como corte seletivo e incêndios continuam afetando a comunidade de vertebrados que ocorrem fora das áreas contínuas de floresta. / Extensive areas across the Earth surface have been modified by human land uses, particularly in the tropical region. Deforestation is one of main sources of emissions of greenhouse gases and the main threat to the conservation of biodiversity and ecosystem services provided by tropical forests. In the context of human-modified landscapes, including forest fragmentation, the main goal of this work is to understand the relationships between land use and land cover dynamics and the changes in the structure and composition of forest vertebrate community and also, the alterations in the quality of surface water in catchments. We assess land use dynamics about 50,000 km² of study area located in Southwestern Brazilian Amazon. By mean of maps of land cover classified from satellite images based in a 36-year monitoring, we observed a forest loss of 24,826 km² related to the expansion of road network from 3158 km to 12863 km in the same period. This result makes the study area as the most deforested of entire Brazilian Amazon. The land use dynamics show that fragmentation is higher in recent deforestation frontier than in both older deforestation and landscapes with few or no deforestation detected. Our results from inference with generalized least square models show that distance to the roads affects negatively the deforestation rates, mainly in flat areas and near to small and large rivers. The generalized linear models with higher relative importance to explain the species richness, aggregate biomass and the index of hunting vulnerability had as predictors the fragment area, number of patches and distance between fragments as major attributes of the landscape that affects the vertebrate community. The forest is important for maintenance of stream water quality, particularly if there is forest cover in the 100 m strips alongside the streams, considering the soil characteristics such as proportion of bases and seasonality. In our GLM multi-model analysis, the higher proportion of forest in surroundings the streams contributes to the increasing of concentrations in the rainy season of aluminum, phosphate, suspension sediments, ammonium and nitrate. At the end, we made consideration about law enforcement and landownership, to preclude the deforestation toward extensive areas of pristine forest. Moreover, we suggest that in fragmented landscapes the conservation efforts to be concentrated in forest restoration, mainly near to rivers, to reduce the isolation of the fragments. We highlighted the importance in monitoring the biodiversity responses to recurrent disturbing sources such as selective logging and accidental forest fires in fragmented landscapes.

Forest-cover in the tropics is changing rapidly due to indiscriminate removal of timber from many localities. The main focus of the study is to develop an operational tool for monitoring biomass and carbon pool of tropical forest ecosystems. The method was applied to a test site of Bangladesh. The research used Landsat ETM+, Landsat TM and IRS pan images of 2001, 1992 and 1999 respectively. Geometrically corrected Landsat ETM+ imagery was obtained from USGS and adjusted to the field using GPS. Historical images were corrected using image-to-image registration. Atmospheric correction was done by modified dark object subtraction method. Stratified sampling design based on the remote sensing image was applied for assessing the above-ground biomass and carbon content of the study area. Field sampling was done during 2002-2003. Dbh and height of all the trees inside the sample plots were measured. Field measurement was finally converted to carbon content using allometric relations. Three different methods: stratification, regression and k-nearest neighbors were tested for combining remote sensing image information and field-based terrestrial carbon pool. Additional field sampling was conducted during 2003-2004 for testing the accuracy. Finally regression method was selected. The amount of carbon released and sequestrated from the ecosystem was estimated. The application of the developed method would be quite useful for understating the terrestrial carbon dynamics and global climate change.