Evaluating, predicting and mapping belowground carbon stores in Kenyan mangroves.

Despite covering only approximately 138,000 km2, mangroves are globally important carbon sinks with carbon density values 3 to 4 times that of terrestrial forests. A key challenge in evaluating the carbon benefits from mangrove forest conservation is the lack of rigorous spatially resolved estimates of mangrove sediment carbon stocks; most mangrove carbon is stored belowground. Previous work has focused on detailed estimations of carbon stores over relatively small areas, which has obvious limitations in terms of generality and scope of application. Most studies have focused only on quantifying the top 1m of belowground carbon (BGC). Carbon stored at depths beyond 1m, and the effects of mangrove species, location and environmental context on these stores, is poorly studied. This study investigated these variables at two sites (Gazi and Vanga in the south of Kenya) and used the data to produce a country-specific BGC predictive model for Kenya and map BGC store estimates throughout Kenya at spatial scales relevant for climate change research, forest management and REDD+ (Reduced Emissions from Deforestation and Degradation). The results revealed that mangrove species was the most reliable predictor of BGC; Rhizophora muronata had the highest mean BGC with 1485.5t C ha-1. Applying the species-based predictive model to a base map of species distribution in Kenya for the year 2010 with a 2.5m2 resolution, produced an estimate of 69.41 Mt C (�� 9.15 95% C.I.) for BGC in Kenyan mangroves. When applied to a 1992 mangrove distribution map, the BGC estimate was 75.65 Mt C (�� 12.21 95% C.I.); an 8.3% loss in BGC stores between 1992 and 2010 in Kenya. The country level mangrove map provides a valuable tool for assessing carbon stocks and visualising the distribution of BGC. Estimates at the 2.5m2 resolution provide sufficient detail for highlighting and prioritising areas for mangrove conservation and restoration.

Os desafios para uma nova agricultura na Amaz��nia.

Dar aten����o para as ��reas com florestas, que representam 82% da Amaz��nia, ou para os 18% j�� desmatados constitui o atual dilema pol��tico. A ��nfase na biodiversidade como sendo a grande op����o futura para a Amaz��nia carrega equ��vocos na busca futur��stica de produtos, esquecendo a biodiversidade do passado e do presente, na qual est��o as grandes oportunidades. Os atuais recursos financeiros do Reducing Emissions from Deforestation and Forest Degradation (REDD) seriam adequados na gera����o de tecnologias apropriadas do que a cria����o de um assistencialismo ambiental. A redu����o dos desmatamentos e queimadas precisa estar acompanhada da incorpora����o de ��reas desmatadas, sob risco de prejudicar as atividades produtivas da Amaz��nia

Carbon dioxide emissions from diesel and compressed natural gas buses during acceleration

Motor vehicle emission factors are generally derived from driving tests mimicking steady state conditions or transient drive cycles. However, neither of these test conditions completely represents real world driving conditions. In particular, they fail to determine emissions generated during the accelerating phase ��� a condition in which urban buses spend much of their time. In this study we analyse and compare the results of time-dependant emission measurements conducted on diesel and compressed natural gas (CNG) buses during an urban driving cycle on a chassis dynamometer and we derive power-law expressions relating carbon dioxide (CO2) emission factors to the instantaneous speed while accelerating from rest. Emissions during acceleration are compared with that during steady speed operation. These results have important implications for emission modelling particularly under congested traffic conditions.

The international regulation of sustainable forest management : doctrinal concepts, governing institutions and implementation

The overarching objective of the research was to identify the existence and nature of international legal principles governing sustainable forest use and management. This research intended to uncover a set of forest legal considerations that are relevant for consideration across the globe. The purpose behind this, is to create a theoretical base of international forest law literature which be drawn upon to inform future international forestry research. This research will be of relevance to those undertaking examination of a particular forest issue or those focusing on forests in a particular region. The thesis explains the underlying legal issues in forest regulation, the dominant international regulatory approaches and makes suggestions as to how international and national forest policy could be improved.

Public Finance for REDD+ in Kenya

Kenya aims to prepare for both public and private Reduced Emission from Deforestation and Degradation (REDD+) investment flows. This chapter examines how current Kenyan law can be used as a starting point for building a regulatory regime to support public sector finance. For present purposes, ���public sector finance��� is defined as money flowing from multilateral international institutions and bi-lateral donor funds. Key issues addressed by this chapter ��� The nature and form of public sector finance for REDD+ in Kenya. ��� The management and laws relating to public funds in Kenya; ��� Mechanisms that can be utilised to manage risk associated with REDD+ investments with a focus on Kenyan anti-corruption laws and policies; ��� The regulatory regime for distributing the benefits from REDD+ investment to relevant forest stakeholders.

Ammonia emissions from pig and cattle slurry in the field and utilization of slurry nitrogen in crop production

Volatilization of ammonia (NH3) from animal manure is a major pathway for nitrogen (N) losses that cause eutrophication, acidification, and other environmental hazards. In this study, the effect of alternative techniques of manure treatment (aeration, separation, addition of peat) and application (broadcast spreading, band spreading, injection, incorporation by harrowing) on ammonia emissions in the field and on nitrogen uptake by ley or cereals was studied. The effect of a mixture of slurry and peat on soil properties was also investigated. The aim of this study was to find ways to improve the utilization of manure nitrogen and reduce its release to the environment. Injection into the soil or incorporation by harrowing clearly reduced ammonia volatilization from slurry more than did the surface application onto a smaller area by band spreading or reduction of the dry matter of slurry by aeration or separation. Surface application showed low ammonia volatilization, when pig slurry was applied to tilled bare clay soil or to spring wheat stands in early growth stages. Apparently, the properties of both slurry and soil enabled the rapid infiltration and absorption of slurry and its ammoniacal nitrogen by the soil. On ley, however, surface-applied cattle slurry lost about half of its ammoniacal nitrogen. The volatilization of ammonia from surface-applied peat manure was slow, but proceeded over a long period of time. After rain or irrigation, the peat manure layer on the soil surface retarded evaporation. Incorporation was less important for the fertilizer effect of peat manure than for pig slurry, but both manures were more effective when incorporated. Peat manure applications increase soil organic matter content and aggregate stability. Stubble mulch tillage hastens the effect in surface soil compared with ploughing. The apparent recovery of ammoniacal manure nitrogen in crop yield was higher with injection and incorporation than with surface applications. This was the case for leys as well as for spring cereals, even though ammonia losses from manures applied to cereals were relatively low with surface applications as well. The ammoniacal nitrogen of surface-applied slurry was obviously adsorbed by the very surface soil and remained mostly unavailable to plant roots in the dry soil. Supplementing manures with inorganic fertilizer nitrogen, which adds plant-available nitrogen to the soil at the start of growth, increased the overall recovery of applied nitrogen in crop yields.

Broad combined orange-red emissions from Eu2+- and Eu3+-doped low-silica calcium aluminosilicate glass

In this paper, a broad combined orange-red emission from Eu2+- and Eu3+-doped low-silica calcium aluminosilicate (LSCAS) glass is reported. Spectroscopic results demonstrate that it is possible to tune the emission wavelength by changing the excitation wavelength in the UV-Vis region. The color coordinates for the emission spectra were calculated, and using the Commission Internationale de l'Eclairage 1931 and 1976 chromatic diagrams, it is possible to note that they are dependent on the excitation wavelength. In addition, the (u', v') color coordinates for the investigated LSCAS samples are close to the Planckian spectrum in the cold region between 2000 and 2600K. Our results show that the Eu:LSCAS system can be used in a white light phosphor when mixed in aggregate with phosphors using green-yellow luminescent ions. (c) 2012 Optical Society of America

Aportaci��n de t��cnicas geoespaciales para la determinaci��n de los niveles de referencia de la deforestaci��n y la degradaci��n de bosques en el ��mbito de proyectos REDD. an��lisis de factores de causalidad subyacentes y directos

La p��rdida de bosques en la Tierra, principalmente en ecosistemas amaz��nicos, es un factor clave en el proceso del cambio clim��tico. Para revertir esta situaci��n, los mecanismos REDD (Reducing Emission from Deforestation and forest Degradation) est��n permitiendo la implementaci��n de actividades de protecci��n del clima a trav��s de la reducci��n de emisiones por deforestaci��n evitada, seg��n los esquemas previstos en el Protocolo de Kioto. El factor t��cnico m��s cr��tico en un proyecto REDD es la determinaci��n de la l��nea de referencia de emisiones, que define la expectativa futura sobre las emisiones de CO2 de origen forestal en ausencia de esfuerzos adicionales obtenidos como consecuencia de la implementaci��n del programa REDD para frenar este tipo de emisiones. La zona del estudio se ubica en la regi��n de San Mart��n (Per��), provincia cubierta fundamentalmente por bosques tropicales cuyas tasas de deforestaci��n son de las m��s altas de la cuenca amaz��nica. En las ��ltimas d��cadas del siglo XX, la regi��n empez�� un acelerado proceso de deforestaci��n consecuencia de la integraci��n vial con el resto del pa��s y la r��pida inmigraci��n desde zonas rurales en busca de nuevas tierras agr��colas. Desde el punto de vista de la investigaci��n llevada a cabo en la tesis doctoral, se pueden destacar dos l��neas: 1. El estudio multitemporal mediante im��genes de sat��lite Landsat 5/TM con el prop��sito de calcular las p��rdidas de bosque entre per��odos. El estudio multitemporal se llev�� a cabo en el per��odo 1998-2011 utilizando im��genes Landsat 5/TM, aplicando la metodolog��a de An��lisis de Mezclas Espectrales (Spectral Mixtures Analysis), que permite descomponer la reflectancia de cada p��xel de la imagen en diferentes fracciones de mezcla espectral. En este proceso, las etapas m��s cr��ticas son el establecimiento de los espectros puros o endemembers y la recopilaci��n de librer��as espectrales adecuadas, en este caso de bosques tropicales, que permitan reducir la incertidumbre de los procesos. Como resultado de la investigaci��n se ha conseguido elaborar la l��nea de referencia de emisiones hist��rica, para el per��odo de estudio, teniendo en cuenta tanto los procesos de deforestaci��n como de degradaci��n forestal. 2. Relacionar los resultados de p��rdida de bosque con factores de causalidad directos e indirectos. La determinaci��n de los procesos de cambio de cobertura forestal utilizando t��cnicas geoespaciales permite relacionar, de manera significativa, informaci��n de los indicadores causales de dichos procesos. De igual manera, se pueden estimar escenarios futuros de deforestaci��n y degradaci��n de acuerdo al an��lisis de la evoluci��n de dichos vectores, teniendo en cuenta otros factores indirectos o subyacentes, como pueden ser los econ��micos, sociales, demogr��ficos y medioambientales. La identificaci��n de los agentes subyacentes o indirectos es una tarea m��s compleja que la de los factores end��genos o directos. Por un lado, las relaciones causa ��� efecto son mucho m��s difusas; y, por otro, los efectos pueden estar determinados por fen��menos m��s amplios, consecuencia de superposici��n o acumulaci��n de diferentes causas. A partir de los resultados de p��rdida de bosque obtenidos mediante la utilizaci��n de im��genes Landsat 5/TM, se investigaron los criterios de condicionamiento directos e indirectos que podr��an haber influido en la deforestaci��n y degradaci��n forestal en ese per��odo. Para ello, se estudiaron las series temporales, para las mismas fechas, de 9 factores directos (infraestructuras, hidrograf��a, temperatura, etc.) y 196 factores indirectos (econ��micos, sociales, demogr��ficos y ambientales, etc.) con, en principio, un alto potencial de causalidad. Finalmente se ha analizado la predisposici��n de cada factor con la ocurrencia de deforestaci��n y degradaci��n forestal por correlaci��n estad��stica de las series temporales obtenidas. ABSTRACT Forests loss on Earth, mainly in Amazonian ecosystems, is a key factor in the process of climate change. To reverse this situation, the REDD (Reducing Emission from Deforestation and forest Degradation) are allowing the implementation of climate protection activities through reducing emissions from avoided deforestation, according to the schemes under the Kyoto Protocol. Also, the baseline emissions in a REDD project defines a future expectation on CO2 emissions from deforestation and forest degradation in the absence of additional efforts as a result of REDD in order to stop these emissions. The study area is located in the region of San Mart��n (Peru), province mainly covered by tropical forests whose deforestation rates are the highest in the Amazon basin. In the last decades of the twentieth century, the region began an accelerated process of deforestation due to road integration with the rest of the country and the rapid migration from rural areas for searching of new farmland. From the point of view of research in the thesis, we can highlight two lines: 1. The multitemporal study using Landsat 5/TM satellite images in order to calculate the forest loss between periods. The multitemporal study was developed in the period 1998-2011 using Landsat 5/TM, applying the methodology of Spectral Mixture Analysis, which allows decomposing the reflectance of each pixel of the image in different fractions of mixture spectral. In this process, the most critical step is the establishment of pure spectra or endemembers spectra, and the collecting of appropriate spectral libraries, in this case of tropical forests, to reduce the uncertainty of the process. As a result of research has succeeded in developing the baseline emissions for the period of study, taking into account both deforestation and forest degradation. 2. Relate the results of forest loss with direct and indirect causation factors. Determining the processes of change in forest cover using geospatial technologies allows relating, significantly, information of the causal indicators in these processes. Similarly, future deforestation and forest degradation scenarios can be estimated according to the analysis of the evolution of these drivers, taking into account other indirect or underlying factors, such as economic, social, demographic and environmental. Identifying the underlying or indirect agents is more complex than endogenous or direct factors. On the one hand, cause - effect relationships are much more diffuse; and, second, the effects may be determined by broader phenomena, due to superposition or accumulation of different causes. From the results of forest loss obtained using Landsat 5/TM, the criteria of direct and indirect conditioning that might have contributed to deforestation and forest degradation in that period were investigated. For this purpose, temporal series, for the same dates, 9 direct factors (infrastructure, hydrography, temperature, etc.) and 196 underlying factors (economic, social, demographic and environmental) with, in principle, a high potential of causality. Finally it was analyzed the predisposition of each factor to the occurrence of deforestation and forest degradation by statistical correlation of the obtained temporal series.

RISKS TO FOOD AVAILABILITY AND ACCESS FROM CLIMATE POLICIES: AN INTEGRATED ASSESSMENT OF REGIONAL FOOD AVAILABILITY AND ACCESS WITH ALTERNATIVE CLIMATE MITIGATION STRATEGIES TO 2050

Although mitigating GHG emissions is necessary to reduce the overall negative climate change impacts on crop yields and agricultural production, certain mitigation measures may generate unintended consequences to food availability and access due to land use competition and economic burden of mitigation. Prior studies have examined the co-impacts on food availability and global producer prices caused by alternative climate policies. More recent studies have looked at the reduction in total caloric intake driven by both changing income and changing food prices under one specific climate policy. However, due to inelastic calorie demand, consumers��� well-being are likely further reduced by increased food expenditures. Built upon existing literature, my dissertation explores how alternative climate policy designs might adversely affect both caloric intake and staple food budget share to 2050, by using the Global Change Assessment Model (GCAM) and a post-estimated metric of food availability and access (FAA). My dissertation first develop a set of new metrics and methods to explore new perspectives of food availability and access under new conditions. The FAA metric consists of two components, the fraction of GDP per capita spent on five categories of staple food and total caloric intake relative to a reference level. By testing the metric against alternate expectations of the future, it shows consistent results with previous studies that economic growth dominates the improvement of FAA. As we increase our ambition to achieve stringent climate targets, two policy conditions tend to have large impacts on FAA driven by competing land use and increasing food prices. Strict conservation policies leave the competition between bioenergy and agriculture production on existing commercial land, while pricing terrestrial carbon encourages large-scale afforestation. To avoid unintended outcomes to food availability and access for the poor, pricing land emissions in frontier forests has the advantage of selecting more productive land for agricultural activities compared to the full conservation approach, but the land carbon price should not be linked to the price of energy system emissions. These results are highly relevant to effective policy-making to reduce land use change emissions, such as the Reduced Emissions from Deforestation and Forest Degradation (REDD).

Sequestration through forestry and agriculture

Current climate mitigation policies have not fully resolved contentious issues regarding the inclusion of carbon sequestration through changes in forestry and agricultural management practices. Terrestrial carbon sinks could be a low-cost mitigation option that fosters conservation and development, yet issues related to accurately documenting the amount of carbon sequestered undermine confidence that emission offsets through sequestration are equivalent to emission reductions. From an atmospheric perspective, net of CO2 removals through sequestration are equivalent to emission reductions over a given period of time. But carbon will not remain sequestered in biomass or soils indefinitely and investments in sequestration could stifle investments in reducing emissions from other sources. Many international climate agreements cap emissions from some countries or sectors but enable participation of uncapped countries or sectors for forestry and agricultural sequestration. This structure can prompt emission increases in parts of the uncapped entities that weaken the value of emission reductions earned through sequestration. This has been a minor issue under the Clean Development Mechanism of the Kyoto Protocol. Reduced emissions through deforestation and degradation is susceptible to the same problems. The purpose of this article is to review the science, politics, and policy that form the basis of arguments for and against the inclusion forestry and agricultural sequestration as a component of current and future international climate mitigation policies.

Allocating community-level payments for ecosystem services initial experiences from a REDD pilot in Tanzania

Payments for ecosystem services (PES) typically reward landowners for managing their land to provide ecosystem services that would not otherwise be provided. REDD���Reduced Emissions from Deforestation and Forest Degradation���is a form of PES aimed at decreasing carbon emissions from forest conversion and extraction in lower-income countries. A key challenge for REDD occurs when it is implemented at the community rather than the individual landowner level. Whilst achieving this community-level reduction relies on individuals changing their interaction with the forest, incentives are not aligned explicitly at the individual level. Rather, payments are made to the community as a single entity in exchange for verified reduced forest loss, as per a PES scheme. In this paper, we explore how community level REDD has been implemented in one multiple-village pilot in Tanzania. Our findings suggest that considerable attention has been paid to monitoring, reporting, verification, and equity. Though no explicit mechanism ensures individual compliance with the group PES, the development of village level institutions, ���social fencing,��� and a shared future through equal REDD payments factor into community decisions that influence the level of community compliance that the program will eventually achieve. However, few villages allocate funds for explicit enforcement efforts to protect the forest from illegal activities undertaken by outsiders.

Spatial assessment of carbon stocks of living vegetation at the national level in Lao PDR

The international mechanism for Reducing Greenhouse Gas Emissions from Deforestation and Forest Degradation (REDD) supposedly offers new opportunities for combining climate mitigation, conservation of the environment, and socio-economic development for development countries. In Laos REDD is abundantly promoted by the government and development agencies as a potential option for rural development. Yet, basic information for carbon management is missing: to date no knowledge is available at the national level on the quantities of carbon stored in the Lao landscapes. In this study we present an approach for spatial assessment of vegetation-based carbon stocks. We used Google Earth, Landsat and MODIS satellite imagery and refined the official national land cover data to assess carbon stocks. Our study showed that more than half (52%) of carbon stock of Laos is stored in natural forests, but that 70% of this stock is located outside of national protected areas. On the basis of two carbon-centered land use scenarios we calculated that between 30 and 40 million tons of carbon could be accumulated in shifting cultivation areas; this is less than 3% of the existing total stock. Our study suggests that the main focus of REDD in Laos should be on the conservation of existing carbon stocks, giving highest priority to the prevention of deforestation outside of national protected areas.

LiDAR remote sensing applied to forest resources assessment

Disponer de informaci��n precisa y actualizada de inventario forestal es una pieza clave para mejorar la gesti��n forestal sostenible y para proponer y evaluar pol��ticas de conservaci��n de bosques que permitan la reducci��n de emisiones de carbono debidas a la deforestaci��n y degradaci��n forestal (REDD). En este sentido, la tecnolog��a LiDAR ha demostrado ser una herramienta perfecta para caracterizar y estimar de forma continua y en ��reas extensas la estructura del bosque y las principales variables de inventario forestal. Variables como la biomasa, el n��mero de pies, el volumen de madera, la altura dominante, el di��metro o la altura media son estimadas con una calidad comparable a los inventarios tradicionales de campo. La presente tesis se centra en analizar la aplicaci��n de los denominados m��todos de masa de inventario forestal con datos LIDAR bajo diferentes condiciones y caracter��sticas de masa forestal (bosque templados puros y mixtos) y utilizando diferentes bases de datos LiDAR (informaci��n proveniente de vuelo nacionales e informaci��n capturada de forma espec��fica). Como consecuencia de lo anterior, se profundiza en la generaci��n de inventarios forestales continuos con LiDAR en grandes ��reas. Los m��todos de masa se basan en la b��squeda de relaciones estad��sticas entre variables predictoras derivadas de la nube de puntos LiDAR y las variables de inventario forestal medidas en campo con el objeto de generar una cartograf��a continua de inventario forestal. El r��pido desarrollo de esta tecnolog��a en los ��ltimos a��os ha llevado a muchos pa��ses a implantar programas nacionales de captura de informaci��n LiDAR aerotransportada. Estos vuelos nacionales no est��n pensados ni dise��ados para fines forestales por lo que es necesaria la evaluaci��n de la validez de esta informaci��n LiDAR para la descripci��n de la estructura del bosque y la medici��n de variables forestales. Esta informaci��n podr��a suponer una dr��stica reducci��n de costes en la generaci��n de informaci��n continua de alta resoluci��n de inventario forestal. En el cap��tulo 2 se eval��a la estimaci��n de variables forestales a partir de la informaci��n LiDAR capturada en el marco del Plan Nacional de Ortofotograf��a A��rea (PNOA-LiDAR) en Espa��a. Para ello se compara un vuelo espec��fico dise��ado para inventario forestal con la informaci��n de la misma zona capturada dentro del PNOA-LiDAR. El caso de estudio muestra c��mo el ��ngulo de escaneo, la pendiente y orientaci��n del terreno afectan de forma estad��sticamente significativa, aunque con peque��as diferencias, a la estimaci��n de biomasa y variables de estructura forestal derivadas del LiDAR. La cobertura de copas result�� m��s afectada por estos factores que los percentiles de alturas. Considerando toda la zona de estudio, la estimaci��n de la biomasa con ambas bases de datos no present�� diferencias estad��sticamente significativas. Las simulaciones realizadas muestran que las diferencias medias en la estimaci��n de biomasa entre un vuelo espec��fico y el vuelo nacional podr��n superar el 4% en ��reas abruptas, con ��ngulos de escaneo altos y cuando la pendiente de la ladera no est�� orientada hacia la l��nea de escaneo. En el cap��tulo 3 se desarrolla un estudio en masas mixtas y puras de pino silvestre y haya, con un enfoque multi-fuente empleando toda la informaci��n disponible (vuelos LiDAR nacionales de baja densidad de puntos, im��genes satelitales Landsat y parcelas permanentes del inventario forestal nacional espa��ol). Se concluye que este enfoque multi-fuente es adecuado para realizar inventarios forestales continuos de alta resoluci��n en grandes superficies. Los errores obtenidos en la fase de ajuste y de validaci��n de los modelos de ��rea basim��trica y volumen son similares a los registrados por otros autores (usando un vuelo espec��fico y parcelas de campo espec��ficas). Se observan errores mayores en la variable n��mero de pies que los encontrados en la literatura, que pueden ser explicados por la influencia de la metodolog��a de parcelas de radio variable en esta variable. En los cap��tulos 4 y 5 se eval��an los m��todos de masa para estimar biomasa y densidad de carbono en bosques tropicales. Para ello se trabaja con datos del Parque Nacional Volc��n Po��s (Costa Rica) en dos situaciones diferentes: i) se dispone de una cobertura completa LiDAR del ��rea de estudio (capitulo 4) y ii) la cobertura LiDAR completa no es t��cnica o econ��micamente posible y se combina una cobertura incompleta de LiDAR con im��genes Landsat e informaci��n auxiliar para la estimaci��n de biomasa y carbono (capitulo 5). En el cap��tulo 4 se valida un modelo LiDAR general de estimaci��n de biomasa a��rea en bosques tropicales y se compara con los resultados obtenidos con un modelo ajustado de forma espec��fica para el ��rea de estudio. Ambos modelos est��n basados en la variable altura media de copas (TCH por sus siglas en ingl��s) derivada del modelo digital LiDAR de altura de la vegetaci��n. Los resultados en el ��rea de estudio muestran que el modelo general es una alternativa fiable al ajuste de modelos espec��ficos y que la biomasa a��rea puede ser estimada en una nueva zona midiendo en campo ��nicamente la variable ��rea basim��trica (BA). Para mejorar la aplicaci��n de esta metodolog��a es necesario definir en futuros trabajos procedimientos adecuados de medici��n de la variable ��rea basim��trica en campo (localizaci��n, tama��o y forma de las parcelas de campo). La relaci��n entre la altura media de copas del LiDAR y el ��rea basim��trica (Coeficiente de Stock) obtenida en el ��rea de estudio var��a localmente. Por tanto es necesario contar con m��s informaci��n de campo para caracterizar la variabilidad del Coeficiente de Stock entre zonas de vida y si estrategias como la estratificaci��n pueden reducir los errores en la estimaci��n de biomasa y carbono en bosques tropicales. En el cap��tulo 5 se concluye que la combinaci��n de una muestra sistem��tica de informaci��n LiDAR con una cobertura completa de imagen satelital de moderada resoluci��n (e informaci��n auxiliar) es una alternativa efectiva para la realizaci��n de inventarios continuos en bosques tropicales. Esta metodolog��a permite estimar altura de la vegetaci��n, biomasa y carbono en grandes zonas donde la captura de una cobertura completa de LiDAR y la realizaci��n de un gran volumen de trabajo de campo es econ��mica o/y t��cnicamente inviable. Las alternativas examinadas para la predicci��n de biomasa a partir de im��genes Landsat muestran una ligera disminuci��n del coeficiente de determinaci��n y un peque��o aumento del RMSE cuando la cobertura de LiDAR es reducida de forma considerable. Los resultados indican que la altura de la vegetaci��n, la biomasa y la densidad de carbono pueden ser estimadas en bosques tropicales de forma adecuada usando coberturas de LIDAR bajas (entre el 5% y el 20% del ��rea de estudio). ABSTRACT The availability of accurate and updated forest data is essential for improving sustainable forest management, promoting forest conservation policies and reducing carbon emissions from deforestation and forest degradation (REDD). In this sense, LiDAR technology proves to be a clear-cut tool for characterizing forest structure in large areas and assessing main forest-stand variables. Forest variables such as biomass, stem volume, basal area, mean diameter, mean height, dominant height, and stem number can be thus predicted with better or comparable quality than with costly traditional field inventories. In this thesis, it is analysed the potential of LiDAR technology for the estimation of plot-level forest variables under a range of conditions (conifer & broadleaf temperate forests and tropical forests) and different LiDAR capture characteristics (nationwide LiDAR information vs. specific forest LiDAR data). This study evaluates the application of LiDAR-based plot-level methods in large areas. These methods are based on statistical relationships between predictor variables (derived from airborne data) and field-measured variables to generate wall to wall forest inventories. The fast development of this technology in recent years has led to an increasing availability of national LiDAR datasets, usually developed for multiple purposes throughout an expanding number of countries and regions. The evaluation of the validity of nationwide LiDAR databases (not designed specifically for forest purposes) is needed and presents a great opportunity for substantially reducing the costs of forest inventories. In chapter 2, the suitability of Spanish nationwide LiDAR flight (PNOA) to estimate forest variables is analyzed and compared to a specifically forest designed LiDAR flight. This study case shows that scan angle, terrain slope and aspect significantly affect the assessment of most of the LiDAR-derived forest variables and biomass estimation. Especially, the estimation of canopy cover is more affected than height percentiles. Considering the entire study area, biomass estimations from both databases do not show significant differences. Simulations show that differences in biomass could be larger (more than 4%) only in particular situations, such as steep areas when the slopes are non-oriented towards the scan lines and the scan angles are larger than 15��. In chapter 3, a multi-source approach is developed, integrating available databases such as nationwide LiDAR flights, Landsat imagery and permanent field plots from SNFI, with good resultos in the generation of wall to wall forest inventories. Volume and basal area errors are similar to those obtained by other authors (using specific LiDAR flights and field plots) for the same species. Errors in the estimation of stem number are larger than literature values as a consequence of the great influence that variable-radius plots, as used in SNFI, have on this variable. In chapters 4 and 5 wall to wall plot-level methodologies to estimate aboveground biomass and carbon density in tropical forest are evaluated. The study area is located in the Poas Volcano National Park (Costa Rica) and two different situations are analyzed: i) available complete LiDAR coverage (chapter 4) and ii) a complete LiDAR coverage is not available and wall to wall estimation is carried out combining LiDAR, Landsat and ancillary data (chapter 5). In chapter 4, a general aboveground biomass plot-level LiDAR model for tropical forest (Asner & Mascaro, 2014) is validated and a specific model for the study area is fitted. Both LiDAR plot-level models are based on the top-of-canopy height (TCH) variable that is derived from the LiDAR digital canopy model. Results show that the pantropical plot-level LiDAR methodology is a reliable alternative to the development of specific models for tropical forests and thus, aboveground biomass in a new study area could be estimated by only measuring basal area (BA). Applying this methodology, the definition of precise BA field measurement procedures (e.g. location, size and shape of the field plots) is decisive to achieve reliable results in future studies. The relation between BA and TCH (Stocking Coefficient) obtained in our study area in Costa Rica varied locally. Therefore, more field work is needed for assessing Stocking Coefficient variations between different life zones and the influence of the stratification of the study areas in tropical forests on the reduction of uncertainty. In chapter 5, the combination of systematic LiDAR information sampling and full coverage Landsat imagery (and ancillary data) prove to be an effective alternative for forest inventories in tropical areas. This methodology allows estimating wall to wall vegetation height, biomass and carbon density in large areas where full LiDAR coverage and traditional field work are technically and/or economically unfeasible. Carbon density prediction using Landsat imaginery shows a slight decrease in the determination coefficient and an increase in RMSE when harshly decreasing LiDAR coverage area. Results indicate that feasible estimates of vegetation height, biomass and carbon density can be accomplished using low LiDAR coverage areas (between 5% and 20% of the total area) in tropical locations.

RED vs. REDD: Biofuel Policy vs. Forest Conservation. Factor Markets Working Document No. 41, May 2013

This paper assesses the complex interplay between global Renewable Energy Directives (RED) and the United Nations programme to Reduce Emissions from Deforestation and forest Degradation (REDD). We examine the interaction of the two policies using a scenario approach with a recursive-dynamic global Computable General Equilibrium model. The consequences of a global biofuel directive on worldwide land use, agricultural production, international trade flows, food prices and food security out to 2030 are evaluated with and without a strict global REDD policy. We address a key methodological challenge of how to model the supply of land in the face of restrictions over its availability, as arises under the REDD policy. The paper introduces a flexible land supply function, which allows for large changes in the total potential land availability for agriculture. Our results show that whilst both RED and REDD are designed to reduce emissions, they have opposing impacts on land use. RED policies are found to extend land use whereas the REDD policy leads to an overall reduction in land use and intensification of agriculture. Strict REDD policies to protect forest and woodland lead to higher land prices in all regions. World food prices are slightly higher overall with some significant regional increases, notably in Southern Africa and Indonesia, leading to reductions in food security in these countries. This said, real food prices in 2030 are still lower than the 2010 level, even with the RED and REDD policies in place. Overall this suggests that RED and REDD are feasible from a worldwide perspective, although the results show that there are some regional problems that need to be resolved. The results show that countries directly affected by forest and woodland protection would be the most economically vulnerable when the REDD policy is implemented. The introduction of REDD policies reduces global trade in agricultural products and moves some developing countries to a net importing position for agricultural products. This suggests that the protection of forests and woodlands in these regions reverses their comparative advantage as they move from being land-abundant to land-scarce regions. The full REDD policy setting, however, foresees providing compensation to these countries to cover their economic losses.