Reducing Emissions from Deforestation and forest Degradation (REDD+) requires developing countries to quantify green-house gas emissions and removals from forests in a manner that is robust, transparent, and as accurate as possible. While shifting cultivation is a dominant practice in several developing countries, there is still very limited information available on how to monitor this land-use practice for REDD+ as little is known about the areas of shifting cultivation or the net carbon balance. In the present work, we propose and test a methodology to monitor the effect of the shifting cultivation on above-ground carbon stocks. We combine multi-year remote sensing information, taken from a 12-year period, with an in-depth community forest carbon stock inventory in Palo Seco Forest Reserve, western Panama. With remote sensing, we were able to separate four forest classes expressing different forest-use intensity and timesince-intervention which demonstrate expected trends in above-ground carbon stocks. The addition of different interventions observed over time is shown to be a good predictor, with remote sensing variables explaining 64.2% of the variation in forest carbon stocks in cultivated landscapes. Multi-temporal and multi-spectral medium resolution satellite imagery is shown to be adequate for tracking land-use dynamics of the agriculture-fallow cycle. The results also indicate that, over time, shifting cultivation has a transitory effect on forest carbon stocks in the study area. This is due to the rapid recovery of forest carbon stocks, which results in limited net emissions. Finally, community participation yielded important additional benefits to measuring

Estimating above-ground biomass in the context of fertilization management requires the monitoring of crops at early stages. Conventional remote sensing techniques make use of vegetation indices such as the normalized difference vegetation index (NDVI), but they do not exploit the high spatial resolution (ground sampling distance < 5 mm) now achievable with the introduction of unmanned aerial vehicles (UAVs) in agriculture. The aim of this study was to compare image mosaics to single images for the estimation of corn biomass and the influence of viewing angles in this estimation. Nadir imagery was captured by a high spatial resolution camera mounted on a UAV to generate orthomosaics of corn plots at different growth stages (from V2 to V7). Nadir and oblique images (30° and 45° with respect to the vertical) were also acquired from a zip line platform and processed as single images. Image segmentation was performed using the difference color index Excess Green-Excess Red, allowing for the discrimination between vegetation and background pixels. The apparent surface area of plants was then extracted and compared to biomass measured in situ. An asymptotic total least squares regression was performed and showed a strong relationship between the apparent surface area of plants and both dry and fresh biomass. Mosaics tended to underestimate the apparent surface area in comparison to single images because of radiometric degradation. It is therefore conceivable to process only single images instead of investing time and effort in acquiring and processing data for orthomosaic generation. When comparing oblique photography, an angle of 30° yielded the best results in estimating corn biomass, with a low residual standard error of orthogonal distance (RSEOD = 0.031 for fresh biomass, RSEOD = 0.034 for dry biomass). Since oblique imagery provides more flexibility in data acquisition with fewer constraints on logistics, this approach might be an efficient way to monitor crop biomass at early stages.

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Cet article s’intéresse à la problématique de l’aménagement du territoire et des inégalités territoriales au Sénégal. Il examine, d’une part, les pratiques courantes d’aménagement du territoire par rapport à la question de la justice spatiale. D’autre part, il montre les effets significatifs de l’aménagement du territoire sur la qualité et le niveau de vie des populations. La méthode porte sur le traitement, l’analyse et la modélisation d’une base de données démographiques, socioéconomiques et d’infrastructures sociales fondamentales des différentes régions. L’analyse en composante principale (ACP) permet d’organiser les 12 variables en deux principaux groupes qui expliquent l’essentiel des données. Elle est suivie d’une cartographie avancée qui montre les spécificités et la dynamique spatiale des processus d’aménagement du territoire, au Sénégal.Our research focuses on the issue of land-use planning and territorial inequalities in Senegal. It first analyzes common practices in land-use planning as regards spatial justice, then explores the significant impacts of land-use planning on the quality of life and standard of living of Senegalese people. The approach adopted involved processing, analyzing and modeling a database of the population and the socio-economic and basic social infrastructures of the country’s different regions. By performing principal component analysis (PCA), we were able to place the variables in two main groups which explain the data. This analysis was followed by advanced mapping to illustrate the particular characteristics and spatial dynamics of the land-use planning process in Senegal.En este artículo se presenta la problemática de la planificación territorial y las desigualdades territoriales en Senegal. Por un lado, se examinan las prácticas corrientes de planificación territorial en relación con la justicia espacial; por otro, se muestran los impactos de la planificación territorial sobre la calidad y el nivel de vida de las poblaciones. El método concierne el tratamiento, análisis y modelización de una fuente de datos demográficos, socio-económicos y de infraestructuras sociales básicas de diferentes regiones. El análisis de la componente principal (ACP) permite organizar las doce variables en dos grupos principales que explican lo esencial de los datos. Le sigue una cartografía avanzada que muestra lo específico y la dinámica espacial de los procesos de planificación territorial en Senegal