Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Space-time monitoring of tropical forest changes using observations from multiple satellites
    Hamunyela, Eliakim - \ 2017
    Wageningen University. Promotor(en): M. Herold, co-promotor(en): J.P. Verbesselt. - Wageningen : Wageningen University - ISBN 9789463436403 - 188
    tropical forests - monitoring - satellites - deforestation - ecological disturbance - tropische bossen - monitoring - satellieten - ontbossing - ecologische verstoring

    Forests provide essential goods and services to humanity, but human-induced forest disturbances have been on ongoing at alarming rates, undermining the capacity for forests to continue providing essential goods and services. In recent years, the understanding of the short-term and long-term impacts of deforesting and degrading forest ecosystems has improved, and global efforts to reduce forest loss are ongoing. However, in many parts of the globe, significant forest areas continue to be lost. To fully protect forest ecosystems efficiently, timely, reliable and location-specific information on new forest disturbances is needed. Frequent and large-area forest mapping and monitoring using satellite observations can provide timely and cost-effective information about new forest disturbances. However, there are still key weaknesses associated with existing forest monitoring systems. For example, the capacity for forest monitoring systems to detect new disturbances accurately and timely is often limited by persistent cloud cover and strong seasonal dynamics. Persistent cloud can be addressed by using observations from multiple satellite sensors, but satellite sensors often have inter-sensor differences which make integration of observations from multiple sensors challenging. Seasonality can be accounted for using a seasonal model, but image time series are often acquired at irregular intervals, making it difficult to properly account for seasonality. Furthermore, with existing forest monitoring systems, detecting subtle, low-magnitude disturbances remains challenging, and timely detection of forest disturbances is often accompanied by many false detections. The overall objective of this thesis is to improve forest change monitoring by addressing the key challenges which hinders accurate and timely detection of forest disturbances from satellite data. In the next paragraphs, I summarise how this thesis tackled some of the key challenges which hamper effective monitoring of forest disturbances using satellite observations.

    Chapter 2 addresses the challenge of seasonality by developing a spatial normalisation approach that allows us to account for seasonality in irregular image time series when monitoring forest disturbances. In this chapter, I showed that reducing seasonality in image time series using spatial normalisation leads to timely detection of forest disturbances when compared to a seasonal model approach. With spatial normalisation, near real-time forest monitoring in dry forests, which has been challenging for many years, is now possible. Applying spatial normalisation in areas where evergreen and deciduous forests co-exist is however challenging. Therefore, further research is needed to improve the spatial normalisation approach to ensure that it is applicable to areas with a combination of different forest types. In particular, a spatial normalisation approach which is forest type-specifics is desirable. In this chapter, forest disturbances were detected by analysing single pixel-time series. Spatial information was only used to reduce seasonality.

    Taking in account the fact that forest disturbances are spatio-temporal events, I investigated whether there is an added-value of combining both spatial and temporal information when monitoring forest disturbances from satellite image time series. To do this, I first developed a space-time change detection method that detects forest disturbances as extreme events in satellite data cubes (Chapter 3). I showed that, by combining spatial and temporal information, forest disturbances can still be detected reliably even with limited historical observations. Therefore, unlike approaches which detect forest disturbances by analysing single pixel- time series, the space-time approach does not require huge amount of historical images to be pre-processed when monitoring forest disturbances. I then evaluated the added-value of using space-time features when confirming forest disturbances (Chapter 4). I showed that using a set of space-time features to confirm forest disturbances enhance forest monitoring significantly by reducing false detections without compromising temporal accuracy. With space-time features, the discrimination of forest disturbances from false detections is no longer based on temporal information only, hence providing opportunity to also detect low-magnitude disturbances with high confidence. Based on the analysis for conditional variable importance, I showed that features which are computed using both spatial and temporal information were the most important predictors of forest disturbances, thus enforcing the view that forest disturbances should be treated as spatio-temporal in order to improve forest change monitoring.

    In Chapter 2 – 4, forest disturbances where detected from medium resolution Landsat time series. Yet, recent studies showed that small-scale forest disturbances are often omitted when using Landsat time series. In Chapter 5, I investigated whether detection of small-scale forest disturbances can be improved by using the 10m resolution time series from recently launched Sentinel-2 sensor. I also investigated whether the spatial normalisation approach developed in Chapter 2 can be used to reduce inter-sensor differences in multi-sensor optical time series. I showed that the 10m resolution Sentinel-2 time series improves the detection of small-scale forest disturbances when compared to 30m resolution. However, the 10m resolution does not supersede the importance of frequent satellite observations when monitoring forest disturbances. I also showed that spatial normalisation approach developed in Chapter 2 can reduce inter-sensor differences in multi-sensor optical time series significantly to generate temporally consistent time series suitable for forest change detection. Spatial normalisation does not completely remove inter-sensor differences, but the differences are significantly reduced.

    Monitoring of forest disturbances is increasingly done using a combination of Synthetic Aperture Radar (SAR) and optical time series. Therefore, Chapter 6 investigated whether the spatial normalisation approach developed in Chapter 2 can also reduce seasonal variations in SAR time series to facilitate the integration of SAR-optical time series for forest monitoring in dry tropical forests. This Chapter demonstrated that seasonal variations in SAR time series can also be reduced through spatial normalisation. As a result, observations from SAR and optical time series were combined to improve near real-time forest change detection in dry tropical forest. In Chapter 7, it is demonstrated that spatial normalisation has potential to also reduce inter-sensor differences in SAR-optical time series, resulting into temporally consistent SAR-optical time series.

    In conclusion, this thesis developed a space-time forest monitoring framework that addresses some key challenges affecting satellite-based forest monitoring. In particular, new methods that allow for timely and accurate detection of forest disturbances using observations from multiple satellites were developed. Overall, the methods developed in this research contribute to our capacity to accurately and timely detect forest disturbances in both dry and humid forests.

    The role of forests in climate change mitigation : a discursive-institutional analysis of REDD+ MRV
    Ochieng, Robert M. - \ 2017
    Wageningen University. Promotor(en): B.J.M. Arts; M. Herold, co-promotor(en): I.J. Visseren-Hamakers; M. Brockhaus. - Wageningen : Wageningen University - ISBN 9789463431712 - 172
    forests - climatic change - mitigation - forest monitoring - developing countries - deforestation - forestry - bossen - klimaatverandering - mitigatie - bosmonitoring - ontwikkelingslanden - ontbossing - bosbouw

    Since the advent of professional forestry in the 17th century, forest monitoring has been part and parcel of forest management, and has been implemented in different forms in many European countries. The practice of forest monitoring was later exported to the European colonies, and has since been taken over and conducted by post-colonial governments in many developing countries. From an earlier focus on assessment of timber stocks, the practice has evolved to include assessments of other forest variables than timber. Despite this evolution, national forest monitoring has remained largely timber-oriented, and a closed system with little participation of actors outside the state forestry bureaucracy. However, the United Nations Framework Convention on Climate Change (UNFCCC) decision on reducing emissions from deforestation and forest degradation, and the role of conservation, sustainable management of forests and enhancement of forest carbon stocks in developing countries (REDD+) has opened up new discussions on forest monitoring in developing countries. Specifically, the global discourse on monitoring, reporting and verification (MRV) of REDD+ outcomes has introduced new ideas and demands on the scope and objectives of forest monitoring, the actors to be involved, and resources to be used. Taken together, the emergence of the REDD+ MRV discourse and associated ideas calls for change in the institutional arrangements for forest monitoring in developing countries. Furthermore, while these ideas and demands are determined and agreed upon in an international negotiation process, they need to be translated and implemented in highly diverse country-specific contexts, with country-specific actors, ideas, interests, and institutions. Translating the REDD+ MRV discourse and ideas into national institutional arrangements thus involves negotiation and contestation among national stakeholders.

    This dissertation examines the performance of REDD+ MRV in terms of its implementation and institutionalization in developing countries, and the political processes by which such institutionalization occurs. Specifically, it examines (1) the institutional effectiveness of REDD+ MRV; (2) how the concept of REDD+ MRV and associated ideas have materialized in new institutional arrangements for forest monitoring in developing countries; and (3) how discursive processes of policymaking and the argumentation and contestation inherent in such processes enable or constrain institutionalization. With this, the dissertation contributes to the literature on REDD+ MRV by examining forest monitoring from a social science perspective. While current research on REDD+ MRV remains highly technical, since it is assumed that forest monitoring is a neutral, apolitical activity, this study argues that monitoring deforestation is also political, and contributes by highlighting the political contestation involved in implementing REDD+ MRV at the national level. The dissertation also contributes to scientific debates on the performance of international environment agreements at the national level, and how contestation and negotiation among domestic stakeholders enable or constrain their institutionalization at the national level.

    Chapter 1 introduces the research presented in this dissertation. It provides an overview of the emergence of reducing emissions from deforestation and forest degradation in developing countries (REDD+) within the United Nations Convention on Climate Change (UNFCCC) as a climate mitigation strategy, and argues that the UNFCCC’s decisions on monitoring, reporting and verification (MRV) for REDD+ pose new ideas and demands for forest monitoring in developing countries. It elucidates the research that has been done on REDD+ MRV so far, identifies gaps in the existing literature on forest monitoring for REDD+, and delineates the objectives of the study. It discusses the theoretical basis and framework for the study, explaining how the main theoretical concept – discursive institutionalism – is combined with the Policy Arrangement Approach (PAA) to examine how REDD+ MRV has been shaped and institutionalized in new or reformed institutional arrangements for forest monitoring in developing countries, and discursive processes by which such institutionalization occurs. After presenting the conceptual framework, four research questions are outlined, namely:

    1. What is the institutional effectiveness of REDD+ MRV in terms of its implementation in developing countries?

    2. How have institutional arrangements for forest monitoring in Peru evolved, and how and to what extent has their evolution been shaped by international discourses on forests, especially REDD+ MRV?

    3. How and to what extent has the concept of MRV become institutionalized in new or reformed institutional arrangements for forest monitoring in Indonesia, Peru and Tanzania, and how can differences in this extent of institutionalization across the countries be explained?

    4. How has discursive politics enabled or constrained institutionalization of MRV in Indonesia, Peru and Tanzania?

    The chapter then describes the study’s overall research design and methodology, and ends by outlining the structure of the dissertation.

    Chapter 2 examines the institutional effectiveness of REDD+ MRV. The chapter draws on regime literature to conceptualize UNFCCC and its decisions on REDD+ MRV as an international institution or regime, and outlines the technical and good governance requirements for MRV. Drawing on Young and Levy’s (1999) framework for assessing effectiveness of international institutions, and building on UNFCCC and IPCC methodological guidelines for Land Use, Land Use Change and Forestry (LULUCF), and good governance literature, it develops criteria and indicators for assessing progress in implementing the identified technical and governance requirements for MRV. Three dimensions on which effectiveness of REDD+ MRV can be evaluated are developed: ‘owning technical methods for MRV’, ‘developing administrative competence’ and ‘integrating good governance’ in MRV. The framework is applied to assess and compare institutional effectiveness of REDD+ MRV in 13 REDD+ countries, based on a review of national and international documents. The Chapter shows that REDD+ countries have high to very high ownership of technical methods. However, the majority of the countries rank only low to moderate on administrative capacity and good governance. This means that although countries have started developing technical methods for MRV, they are yet to develop the competence necessary to administer MRV and to incorporate aspects of good governance in MRV. The chapter explains the scores and suggest ways of improving implementation of REDD+ MRV.

    Chapter 3 examines how and to what extent global discourses and ideas on forests, especially the concept of REDD+ MRV, have shaped institutional arrangements for forest monitoring in developing countries, using the case of Peru. It draws on discursive institutionalism to conceptualize REDD+ MRV as a discourse and identify the ideas represented in the discourse. It then combines discursive institutionalism with the policy arrangement approach to craft a framework for examining the extent to which REDD+ MRV, and other global discourses, have shaped national institutional arrangements for forest monitoring in Peru. An analytical distinction is made between ‘shallow’ and ‘deep’ institutional change. The chapter identifies three distinct discourses – productivist forest philosophy, multiple-use and sustainable forest management philosophies and REDD+ MRV – that have shaped forest monitoring in Peru. The chapter shows that while all the three discourses have shaped the scope and objectives of forest monitoring, the actors involved, resources used, and rules governing forest assessments, none of them has led to ‘deep’ institutionalization of forest monitoring. On REDD+ MRV specifically, the chapter shows that it has expanded the scope and objectives of forest assessments in Peru, inspired the mobilization of new actors and resources, and spawned the development of new rules to govern forest monitoring. However, these institutional changes are not yet ‘deep’, since the new rules for forest inventories have not yet been formally adopted, and the agencies envisioned to implement forest monitoring have not been established. The chapter concludes that forest monitoring in general, and REDD+ MRV in particular, is only shallowly institutionalized in Peru.

    Chapter 4 compares how and to what extent the concept of REDD+ MRV has institutionalized in Indonesia, Peru and Tanzania. To do so, the chapter draws on insights from discursive institutionalism operationalized by means of the policy arrangement approach to develop the analytical categories of ‘shallow’, ‘shallow-intermediate’, ‘deep-intermediate’ and ‘deep’ institutionalization, and uses these categories to examine the extent of institutionalization across the countries. The chapter shows that in all three countries, REDD+ MRV has institutionalized in new or revised aims, scope and strategies for forest monitoring, and the development of new agencies and mobilization of new actors and resources. New legislation to anchor forest monitoring in law, and procedures to institutionalize the roles of the various agencies, are also being developed. Nevertheless, the extent of institutionalization of MRV varies across the countries, with Indonesia experiencing ‘deep’ institutionalization, Peru ‘shallow-intermediate’, and Tanzania ‘intermediate-deep’ institutionalization. To explain the differences in institutionalization, the chapter examines the theoretical factors for discourse institutionalization and their manifestation in each country. It shows that the relatively ‘deep’ institutionalization of REDD+ MRV in Indonesia and Tanzania is due to the presence of all five factors for discourse institutionalization. Only one factor is found to be present in Peru, and the ‘shallow- intermediate’ institutionalization of REDD+ is largely due to the absence of other factors. Based on the findings and conclusions, the chapter draws lessons to inform institutionalization of MRV in other countries.

    Chapter 5 examines how the discursive politics of MRV policymaking has enabled or constrained institutionalization of REDD+ MRV in Indonesia, Peru and Tanzania. To do this, it draws on the concept of discourse – understood as ideas and the interactive process of policymaking and public deliberation – to examine the actors involved in MRV policy development in the respective countries, and how the deliberation, argumentation and contestation among them (discursive politics) have enabled or constrained institutionalization. The chapter shows that in all countries, the methodologies to be used for MRV, the actors to be involved and their roles were contentious. However, it shows that in Indonesia and Tanzania, where there was a broad-based national discourse on MRV, and where policy actors agreed on the strategies to implement MRV and the role of different actors in forest monitoring, there is relatively ‘deep’ institutionalization compared to Peru, where such discourse and agreement were lacking. The chapter discusses how the discursive process facilitated institutionalization of REDD+ MRV in Indonesia and Tanzania and constrained the same in Peru. It concludes that how discursive politics is played matters in institutionalization.

    Chapter 6 presents the conclusions on the study. It draws on the empirical chapters to answer the research questions, concluding that majority (60%) of the analysed countries has achieved at least a ‘moderate’ institutional effectiveness for MRV. Further, it concludes that the concept of REDD+ MRV has materialized in reformed institutional arrangements for forest monitoring in Indonesia, Peru and Tanzania, albeit to varying degrees. The chapter also concludes that forest monitoring for REDD+ is not only a technical activity, but is also political. Specifically, it concludes that decisions on what exactly is to be monitored and reported, by whom and using what methods are determined through political negotiations, and that how this political process is managed has a significant influence on how, and the extent to which, MRV is institutionalized. After drawing the conclusions, the chapter reflects on the key theoretical concepts used in the study by outlining how discursive institutionalism and the policy arrangement approach can be used to enrich one another. The chapter ends by outlining several policy recommendations. First, it recommends that while the development of new agencies to implement REDD+ MRV is necessary in some countries, care should be taken to avoid establishment of many agencies. Where possible, policy makers and donors should consider working with and strengthening existing agencies before deciding to establish new agencies. Second, it recommends that more investments be directed to organizing inclusive MRV policy coordination processes, since the politics involved in these processes determine the extent to which REDD+ MRV is institutionalized. Lastly, investments in policy coordination should be accompanied with investments in broader communicative political discourse to enlighten all REDD+ stakeholders on MRV policy processes and the strategies being proposed, while seeking the views and feedback these strategies. This is necessary if the proposed strategies are to be legitimate in the eyes of key REDD+ stakeholders.

    REDD+ and Climate Smart Agriculture in landscapes : from national design to local implementation
    Salvini, G. - \ 2016
    Wageningen University. Promotor(en): Arnold Bregt; Martin Herold, co-promotor(en): Arend Ligtenberg. - Wageningen : Wageningen University - ISBN 9789462578371 - 143
    climate adaptation - environmental policy - governance - un - landscape management - deforestation - klimaatadaptatie - milieubeleid - governance - vn - landschapsbeheer - ontbossing

    Global challenges posed by an increasing food demand and climate change call for innovative mechanisms that consider both agriculture and forests. Agriculture and forests are deeply interconnected in mosaic landscapes, just as multiple pieces of the same puzzle. These pieces are handled by numerous stakeholders with different and often contrasting goals. Hence landscape management is steered by power, access to scarce resources, but also vulnerability and hazards. In this thesis I analyze the roles each stakeholder plays on these dynamics, including policy makers, agribusiness actors and subsistence farmers. I explore landscapes as interconnected tiles of a game, in which players are real stakeholders and their goals determine land use dynamics on the game board just as in reality. Sometimes agreements made in the game translate to real-life actions influencing policy and management decisions. Other times the game is just fun and eventually contributes to social learning and trust.

    Optimising land use in Central Kalimantan Province, Indonesia : modelling ecosystem benefits and land use dynamics
    Suwarno, Aritta - \ 2016
    Wageningen University. Promotor(en): Rik Leemans; Lars Hein, co-promotor(en): Hans-Peter Weikard. - Wageningen : Wageningen University - ISBN 9789462578739 - 156
    land use - deforestation - decentralization - ecosystem services - ecosystems - forest policy - forests - modeling - kalimantan - indonesia - landgebruik - ontbossing - decentralisatie - ecosysteemdiensten - ecosystemen - bosbeleid - bossen - modelleren - kalimantan - indonesië

    The rising global population has increased the demand for food, renewable energy and other materials. Yet at the same time to meet this demand requires land and the amount of available land is finite. Considering the importance of land and ecosystems in providing benefits for human, I conducted four independent research on the socio-economic and biophysical aspects of ecosystem service, in Central Kalimantan Province, Indonesia. The first three independent studies were used to understand ecosystem management under decentralised forest governance in Indonesia and its influence on ecosystems, ESs and the benefits that different beneficiaries receive. The fourth study combines the outcomes from the previous three studies to assess and select the most appropriate areas for conservation and community development. As the results, I show the applicability of the ecosystem services concept and land-use modelling in optimising land-use under certain decentralised forest governance systems. My thesis’ results were obtained through the application of methods and steps that integrated a comprehensive set of qualitative and quantitative analyses to support land-use optimisation in the Kapuas Protected Forest Management Unit. My results can inform decision makers on the options of land-use optimisation and the consequences of their management decisions regarding land-use intensification, nature conservation and local economic conditions. I show how land-use optimisation provides an important step in preventing further land degradation and ecosystem loss.

    Carbonizing forest governance: analyzing the consequences of REDD+ for multilevel forest governance
    Vijge, M.J. - \ 2016
    Wageningen University. Promotor(en): Arthur Mol, co-promotor(en): Aarti Gupta. - Wageningen : Wageningen University - ISBN 9789462576445 - 178
    forest policy - governance - deforestation - environmental degradation - forests - carbon - bosbeleid - governance - ontbossing - milieuafbraak - bossen - koolstof

    Carbonizing forest governance:

    Analyzing the consequences of REDD+ for multilevel forest governance

    Marjanneke J. Vijge

    Despite the fifty years of global action to combat deforestation and forest degradation, the world is still losing its forests at great scale. A recent governance initiative that has raised high expectations to address global deforestation is Reducing Emissions from Deforestation and forest Degradation (REDD+), negotiated under the United Nations Framework Convention on Climate Change (UNFCCC). The idea of REDD+ is to compensate developing countries for their forest-related carbon emission reductions. Through REDD+, forests are governed for their carbon content. I therefore see REDD+ as the embodiment of what I call a “carbonization” of forest governance. This thesis analyzes the consequences of carbonization for multilevel forest governance. It studies whether carbonization leads to 1) a simplification of forest governance through a prime focus on carbon, or a focus on multiple carbon and non-carbon benefits; 2) a centralization or dispersion of authority; 3) a privileging of scientific knowledge—what I call a technicalization—or a diversity in the production and use of knowledge; and 4) a primary reliance on market instruments—what I refer to as marketization—or reliance on a mix of market and non-market instruments. I discuss whether REDD+ can be seen as a case of increased homogenization of environmental governance through simplification, centralization, technicalization, and/or marketization.

    The research questions are as follows:

    1. How does the carbonization of forest governance manifest itself at different levels, and with what consequences for multilevel forest governance?

    2. What does this analysis of the consequences of carbonization reveal about the prospects of a homogenization of environmental governance?

    This thesis uses discourses as proxies for how and with what consequences the carbonization of forest governance manifests itself. The thesis analyzes how REDD+ is being framed by policy actors and practitioners, and operationalized in policy, institutional and project developments and design. Triangulation of data is established through reliance on qualitative and quantitative research methods, including semi-structured interviews, surveys, reviews of primary and secondary literature, and direct and participant observation during field visits, project meetings and conferences.

    Chapter 2 analyzes how carbonization manifests itself in UNFCCC policy debates and developments surrounding measuring, reporting and verification (MRV) systems that are centrally implicated in REDD+. This chapter shows that at the global level, REDD+ is framed as a mechanism to facilitate results-based compensation for carbon emission reductions, to be measured through national, state-based, expert-led MRV systems. The chapter argues that this may well induce a simplified focus on carbon, a technicalization of forest governance, and a centralization of authority in national state agencies responsible for measuring and accounting for forest carbon units. This might marginalize non-carbon forest services and empower certain groups of actors such as technical experts at the cost of, for example, local communities. Who will be empowered through REDD+, however, ultimately depends on the context-specific operationalization and implementation of REDD+ at the national and local level.

    Chapter 3 contains an in-depth case study of how carbonization manifests itself in the Green India Mission (GIM), the cornerstone of India’s national REDD+ strategy. The chapter shows that the GIM frames REDD+ as an opportunity to synergistically generate carbon and non-carbon benefits, and promote a further devolution of authority in Indian forest governance to local communities. Chapter 3 nevertheless concludes that this is not likely to be realized without significant investments in benefit-sharing mechanisms and biodiversity and community-based monitoring systems in India.

    Chapter 4 presents the in-depth case study of the first REDD+ pilot project in India. The chapter analyzes the prominence of REDD+-related discourses among stakeholders and in project design. The chapter shows that the manifestation of carbonization at project level can be very different from the dominant framing of REDD+ at the global level as a carbon-centric, centralized and technocratic mechanism. The project case study shows how the carbonization of forest governance might become a vehicle to generate multiple carbon and non-carbon benefits, diversify the production and use of knowledge and the types of actors involved therein, disperse authority among actors involved in forest governance, and diversify reliance on both market- and fund-based finances.

    Chapter 5 contains a cross-country comparative analysis of the prominence of REDD+-related discourses among national policy actors and in national REDD+ policy documents of seven countries: Cameroon, Indonesia, Nepal, Papua New Guinea, Vietnam, Peru and Tanzania. The chapter shows that though REDD+ is mostly framed as a mechanism to generate carbon and non-carbon benefits, most countries pay very little attention to non-carbon monitoring. Almost all countries lay out detailed plans to diversify the production and use of knowledge through the involvement of local communities in REDD+ MRV systems, but currently lack the institutional capacity to implement such plans. Almost all REDD+ policy documents plan for a national state agency to account for and distribute REDD+ payments. There is, however, strikingly little discussion of how to finance REDD+. The chapter argues that a simplification, a centralization and, to a lesser extent, a technicalization of national forest governance are possible consequences of carbonization.

    The concluding chapter shows that carbonization of forest governance manifests itself differently at different levels of governance, with varying consequences for multilevel forest governance. Though homogenization does not yet occur, it may happen in the long run due to the centralization of authority that countries envision in accounting for and distributing REDD+ payments, as well as countries’ capacity gaps in non-carbon and community-based monitoring, which make a simplification and technicalization of national forest governance possible consequences of REDD+. In answering the second research question regarding the prospects of a homogenization of environmental governance, the case of REDD+ shows that developing countries retain authority to design policies, but in diversified ways. I argue that though diversity in policies and practices exist, this goes hand in hand with—and sometimes even flows from—efforts to homogenize in order to measure and regulate environmental outcomes at central (global and/or national) levels. As such, the challenges facing global environmental governance lie not only in measuring and controlling environmental outcomes, but also in managing the diversity and fragmentation that arise from these efforts.

    Spatial modelling and ecosystem accounting for land use planning: addressing deforestation and oil palm expansion in Central Kalimantan, Indonesia
    Sumarga, E. - \ 2015
    Wageningen University. Promotor(en): Lars Hein. - Wageningen : Wageningen University - ISBN 9789462574854 - 156
    landgebruiksplanning - landgebruik - modelleren - ontbossing - oliepalmen - ecosysteemdiensten - ecosystemen - kalimantan - indonesië - land use planning - land use - modeling - deforestation - oil palms - ecosystem services - ecosystems - kalimantan - indonesia

    Ecosystem accounting is a new area of environmental economic accounting that aims to measure ecosystem services in a way that is in line with national accounts. The key characteristics of ecosystem accounting include the extension of the valuation boundary of the System of National Accounts, allowing the inclusion of a broader set of ecosystem services types such regulating services and cultural services. Consistent with the principles of national account, ecosystem accounting focuses on assessment of the contribution of ecosystem in generating benefits for human well-being. Those valuation characteristics allow ecosystem accounting to explicitly visualize the comprehensive values of ecosystem contribution, and integrate them in a standardized national account.

    There is a wide range of potential application of ecosystem accounting in natural resource management and environmental preservation. This includes the provision of basic data on the values of multiple ecosystem services (both in terms of physical quantities and monetary values), monitoring ecosystem services dynamics, analyzing impacts of land-use change and land management on the trade-offs of ecosystem services, and development of ecosystem services based land-use planning. Ecosystem accounting approach has also been widely involved in addressing critical environmental issues such as deforestation, GHG emissions, and biodiversity conservation.

    Considering the spatial heterogeneity of ecosystem services distribution, spatial analysis is a key element in ecosystem accounting. The availability of spatial information of the values of ecosystem services creates opportunity for a broad range of applications required for land-use planning and management, such as identification of areas with high variability of ecosystem services (often called as ecosystem services hotspots) and areas with high aggregate values of ecosystem services, identification of ecosystem services supply and ecosystem services demand interaction, and analysing the impacts of land-use change on the trade-offs of ecosystem services. Most importantly, spatial information of a comprehensive set of ecosystem services values allows land-use planners to analyse the relationship between any options of land management and the existence of a combination of ecosystem services, hence the best management type which optimize the provision of ecosystem services can be formulated.

    The objective of this thesis is to develop an ecosystem services approach to land-use planning through integration of ecosystem accounting and spatial modelling, with a specific case study on deforestation and oil palm expansion in Central Kalimantan Indonesia. The main motivations of this study includes the high rate of deforestation and oil palm expansion in Central Kalimantan, the environmental degradation related to the deforestation such as greenhouse gas emissions and biodiversity loss, the uncertainty of provincial land-use planning, and the lack of experiences on the integration of ecosystem accounting in land-use planning.

    In chapter 2 of this thesis, seven key ecosystem services (timber production, rattan production, oil palm production, paddy rice production, carbon storage, carbon sequestration, and wildlife habitat) are assessed and mapped at a provincial scale. The ecosystem services are assessed in term of physical quantities. Three mapping techniques are applied: spatial interpolation, lookup tables, and Maximum Entropy (Maxent) modelling. An ecosystem services based land-use planning is tested using the seven ecosystem services maps to identify areas for oil palm expansion. This study shows that selection of the best spatial modelling technique for ecosystem services mapping highly depends on the availability of input data and the characteristics of spatial distribution of ecosystem services. This study also demonstrates the significant support of spatial information of ecosystem services in provincial land-use planning.

    In chapter 3, six ecosystem services mapped in chapter 2 (timber production, rattan production, oil palm production, paddy rice production, carbon sequestration, and wildlife habitat) are valued in monetary terms. The valuation also includes additional cultural service, i.e. nature recreation. Two valuation methods consistent with the principles of ecosystem accounts are applied: resource rent valuation and costs based approach. The monetary values of ecosystem services are then mapped, allowing analysis on the aggregate values of the seven ecosystem services in different land-use types. This study shows the capability of resource rent valuation in filtering and visualizing the value of ecosystem contribution in providing benefits that have market values, and the applicability of a costs based approach for carbon sequestration valuation. However, application of the cost based approach is considered inappropriate in monetary valuation of biodiversity habitat, and further improvement is required. This study also shows how the trade-offs of ecosystem services from the past and the potential land-use change can be analyzed based on the spatial information of monetary values of ecosystem services.

    Chapter 4 of this thesis presents land-use change modelling, with a specific case of modelling oil palm expansion in Central Kalimantan. An integrated deductive inductive modelling is developed, using logistic regression and scenario based modelling. The scenarios used in the modelling consist of two scenarios reflecting the past and the current policies on oil palm expansion, i.e. a business as usual scenario and a moratorium scenario, and one alternative scenario, i.e. the sustainable production scenario, developed based on stakeholder workshop and ecosystem services approach studied in chapter 2. Based on the monetary values of ecosystem services valued and mapped in chapter 3, the societal costs and benefits of oil palm expansion based on the three policy scenarios are then analyzed. The model forecasts the continuation of strong oil palm expansion in the period 2015 – 2020, in particular in case of the business as usual scenario, and forecasts that oil palm expansion would level off in the period 2020 – 2025 in all three scenarios. In the business as usual scenario, this expansion would lead to substantial net costs to society resulting from a loss of ecosystem services, particularly from carbon emission emissions. The sustainable production scenario provides the highest net benefits to society, however, implementation of this scenario requires fundamental change of current land-use policy.

    Chapter 5 presents hydrological and economic impacts of oil palm development on peat, with a case study in the ex mega rice project area, Central Kalimantan. Hydrological aspect of oil palm development have not been studied in the previous chapters, and this chapter addresses this aspect through modelling three types of flooding on drained peatland for oil palm: impaired drainability, frequent flooding, and near permanent inundation. The model integrates current knowledge on subsidence rates and drinage limits, and uses a high resolution LiDAR DEM. The results of the model are presented up to 2136. The economic impacts are analysed through two land-use scenarios: the oil palm scenario assuming all peatlands in the study area will be converted into oil palm, and the mix scenario combining natural forest preservation, jelutung forest development and oil palm plantation. This study shows that in 100 years’ time only around 10% of the area would still be suitable for oil palm. This study also shows that under the first scenario, the social costs of carbon emissions considerably outweigh the benefits of oil palm production. In term of private benefits, the mixed land-use option scores better even at the first plantation cycle. The mix land-use scenario also potentially preserve about 84,000 ha habitat for orangutan. This study provides useful inputs for a comprehensive analysis on the sustainability of oil palm development on peatland.

    In general this thesis demonstrates the significant contribution of ecosystem accounting and spatial modelling for land-use planning. Valuation methods and spatial modelling techniques developed in this study provide basis for completing ecosystem accounting in Central Kalimantan, with potential applicability in other regions. By addressing the critical environmental issues in Central Kalimantan, i.e. deforestation and oil palm expansion and their environmental and economic impacts, this study contributes to formulate a better land-use management, which facilitates the need for oil palm development while maintaining the provision of important ecosystem services.

    Inauguratie Pieter Zuidema
    Zuidema, P.A. - \ 2015
    Wageningen UR
    tropische bossen - ontbossing - ecosysteemdiensten - bosfragmentatie - klimaatverandering - bosbouweconomie - bosexploitatie - tropical forests - deforestation - ecosystem services - forest fragmentation - climatic change - forest economics - forest exploitation
    Hoogleraar Pieter Zuidema vertelt over zijn onderzoek naar invloed van global change op tropische bossen.
    Land use and land cover dynamics in the Brazilian Amazon: understanding human-environmental interactions
    Souza Soler, L. de - \ 2014
    Wageningen University. Promotor(en): Tom Veldkamp; Peter Verburg, co-promotor(en): Kasper Kok. - Wageningen : Wageningen University - ISBN 9789462570887 - 186
    dynamiek van het ruimtegebruik - ontbossing - amazonas - brazilië - remote sensing - land use dynamics - deforestation - amazonas - brazil - remote sensing

    Land use and land cover dynamics are a result of the interactions between human activities and the environment. The objective of this thesis is to analyze Amazonian land use and land cover pattern dynamics in order to identify the underlying system dynamics. By combining empirical statistical models and Fuzzy Cognitive Mapping, feedbacks in the human-environment system can be explored to identify more sustainable development pathways. The results show that specific feedback loops can lead to a sustainable human-environment system in the Brazilian Amazon, e.g., in case policies such as Payment for Ecosystems Services (PES) and Reducing Emissions from Deforestation and Forest Degradation (REDD) are enforced. Also, the analysis indicates that land market regulations and the enforcement of the Forestry Code can reduce deforestation. It is concluded that policy effectiveness of sustainable land use practices can be better evaluated by using the combination of statistical and cognitive methods. In summary, the thesis illustrates that added value in analyzing land system changes is achieved if insights obtained at different scales are combined through different methods of analysis.

    The Multi-Stakeholder Dialogue in Ghana : Towards a negotiated solution to illegal chainsaw milling
    Mckeown, J.P. ; Rozemeijer, N. ; Wit, M. - \ 2013
    Wageningen : Tropenbos International - ISBN 9789051131147 - 44
    ontbossing - houtkap - illegale kap - ghana - deforestation - logging - illicit felling - ghana
    From landless to forestless? : settlers, livelihoods and forest dynamics in the Brazilian Amazon
    Homero Diniz, F. - \ 2013
    Wageningen University. Promotor(en): Bas Arts, co-promotor(en): Kasper Kok; Marjanke Hoogstra-Klein. - [S.l.] : s.n. - ISBN 9789461735836 - 184
    ontbossing - landloosheid - bossen - bosdynamiek - bosecologie - middelen van bestaan - strategieën voor levensonderhoud - bosbedrijfsvoering - brazilië - deforestation - landlessness - forests - forest dynamics - forest ecology - livelihoods - livelihood strategies - forest management - brazil

    Keywords: deforestation; remote sensing; mental models; stakeholders’ perceptions; agrarian reform

    Over the last decades, hundreds of thousands of families have settled in projects in the Brazilian Amazon within the Agrarian Reform Program (ARP) framework, the rationale being to enable settlers to earn their living by small-scale farming and produce an agricultural surplus for sale. Further, the Brazilian Forestry Code requires settlers not to deforest more than 20% of forest on their properties, but in many projects settlers have deforested larger areas than this. However, specific questions about whether the settlers’ activities are, at the very least, providing their livelihoods, and about the effects of these choices on deforestation over time, have hardly been addressed. Located in five settlement projects in Eldorado do Carajás, southeast Pará State, this research investigated how settlers make their living; how their activities and practices affect forest cover changes; and how future prospects for both, i.e. people and forest, are envisioned. Within the framework of the sustainable livelihoods approach, the results indicated that settlers rely on three livelihood strategies (livestock-, diversified-, and off-farm-oriented), with dairy cattle as the main agricultural activity. These strategies are shaped by several factors, such as agrarian reform policies (e.g. credit) and settlers’ background. Forest dynamics analysis showed a clear recent increase in forest (2005–2010) at municipal level, suggesting that the first steps towards forest transition are taking place. However, settlers do not perceive secondary regrowth as ‘real’ forest, implying a high risk of future deforestation in these areas; but these areas can also be seen as having a high potential of remaining forested if technological innovations in agricultural activities and practices become available in the (near) future. The research findings also indicated the necessity to analyse livelihoods and forest cover changes as dynamic processes. It was not possible to determine one-to-one relationships and general patterns of effects of livelihood trajectories on forest dynamics due to the complexities involved, although analysis of individual household- and property-level cases offered insights into factors driving both. Fuzzy cognitive mapping was used to capture current settlers’ perceptions about their realities. The results indicated that settlers have similar perceptions of the factors that affect their livelihood security and environmental sustainability, independent of livelihood strategy adopted. However, differences were found in the relationships among factors and the weight attributed to each relationship, creating fundamentally different system dynamics for each livelihood strategy. Consequently, strong trade-offs exist between livelihood security and environmental sustainability independent of livelihood strategy and in (nearly) all future scenario analyses. The research produced five key messages: 1) small farmers within the studied ARP projects are less poor than often assumed; they achieve livelihood security through on- and off-farm income; 2) there is a strong trade-off between livelihood security and environmental sustainability; hence primary forest deforestation continues, although the first signs of secondary forest transitions have been observed; 3) the settlers’ contribution to deforestation is less than often assumed because they contribute to emerging forest transitions and because local deforestation peaked before the projects; 4) policies strongly affect the settlers’ realities; hence their views are crucial for effective policymaking, including both the Forestry Code and agrarian reform policies; and 5) livelihood trajectories and forest dynamics models are more appropriate to capture the realities of the human–environment systems in the Brazilian Amazon than livelihoods as snapshots and unidirectional deforestation models.

    Forestry in MAGNET : a new approach for land use and forestry modelling
    Woltjer, G.B. - \ 2013
    Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-werkdocument 320) - 44
    bosbouw - ontbossing - landgebruik - modelleren - verandering - forestry - deforestation - land use - modeling - change
    This report discusses improvements of MAGNET in order to improve the analysis of land use change and forestry dynamics. In the standard approach only a difference is made between agricultural land, non-used land that can be potentially used for agriculture, and land that never can be used for agriculture. In the new approach different other land cover types like built - up area and forestry are distinguished. Also the symmetry requirement of the old model is replaced by a more sophisticated mechanism where stylized facts that forest land is normally converted into grassland, and grassland in to cropland can be acknowledged. Next to this the forestry sector is implemented as a sector where land use and harvest of the land are not directly coupled. An explicit function is included that acknowledges that deforestation generates a once and for ever production of wood and other forestry products.
    LULUCF values under the Kyoto Protocol : background document in preparation of the National Inventory Report 2011 (reporting year 2009)
    Wyngaert, I.J.J. van den; Kuikman, P.J. ; Lesschen, J.P. ; Verwer, C.C. ; Vreuls, H.J.J. - \ 2011
    Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-werkdocument 266) - 70
    broeikasgassen - kooldioxide - emissie - klimaatverandering - bebossing - ontbossing - nederland - greenhouse gases - carbon dioxide - emission - climatic change - afforestation - deforestation - netherlands
    This report collects all background information that is used for the 2011 submission under the Kyoto Protocol (KP) for the Netherlands. It includes the full text of the National Inventory Report (NIR)-II for LULUCF, as well as a description of the table-bytable methodologies, choices and motivations. In 2009 afforestation and reforestation activities produced a sink of 546.68 Gg CO2 equivalents while deforestation caused an emission of 780,45 Gg CO2 equivalents. These values were based on changes in above- and belowground biomass, dead wood, litter and soil (mineral as well as organic), and agricultural lime application on deforested areas. The values for 2008 were recalculated from last year, and the recalculation included changes due to: (i) This was the first year emissions from mineral and organic soils were reported for Afforestation, Reforestation, and Deforestation (ARD). (ii) An error in harvested wood was corrected, and (iii) The calculation of dead wood was improved. Some minor gaps remain to be solved in the coming year(s), especially for the estimation of uncertainty of all reported values.
    Carbon pools in tropical peat forest : towards a reference value for forest biomass carbon in relatively undisturbed peat swamp forests in Southeast Asia
    Verwer, C.C. ; Meer, P.J. van der - \ 2010
    Wageningen : Alterra (Alterra-report 2108)
    veengebieden - veengronden - tropische bossen - kooldioxide - ontbossing - biomassa - koolstofvastlegging - gegevens verzamelen - ligstro - zuidoost-azië - peatlands - peat soils - tropical forests - carbon dioxide - deforestation - biomass - carbon sequestration - data collection - litter - south east asia
    Carbon budgets and carbon sequestration potential of Indian forests
    Kaul, M. - \ 2010
    Wageningen University. Promotor(en): Frits Mohren, co-promotor(en): V.K. Dadhwal. - [S.l. : S.n. - ISBN 9789085858089 - 181
    koolstofvastlegging - koolstof - kringlopen - bossen - bio-energie - landgebruik - ontbossing - bebossing - biomassa - india - carbon sequestration - carbon - cycling - forests - bioenergy - land use - deforestation - afforestation - biomass - india

    Keywords: Carbon uptake, Forest biomass, Bioenergy, Land use change, Indian forests, Deforestation, Afforestation, Rotation length, Trees outside forests.

    Global climate change is a widespread and growing concern that has led to extensive international discussions and negotiations. Responses to this concern have focused on reducing emissions of greenhouse gases, especially carbon dioxide, and on measuring carbon absorbed by and stored in forests and soils. Forests are a significant part of the global carbon cycle. The amount of carbon stored, however, changes over time as forests grow and mature. Land use changes, especially afforestation and deforestation may have major impacts on carbon storage. An option for mitigating the accumulation of CO2 in the atmosphere is the enhanced sequestration of carbon by the biosphere through massive reforestation or sustainable afforestation programs. Reducing the rate of deforestation reduces carbon losses from the biosphere. Establishing plantations on former agricultural land may have less of an impact on increasing carbon sequestration than restoring natural forests. The focus of this study was to estimate the carbon budgets and carbon sequestration potential of Indian forests, assessing the possible impacts of land-use changes and climate change on carbon stocks of Indian forests, and the mitigation potential of using forest-based bioenergy for fossil fuel substitution. The results from this study show that over a 10-year period from 1992-2002, Indian forests have acted as a small carbon sink. Thus, India with high population density, low forest cover per capita, high dependence of a large part of human population on forests, and a predominantly agrarian economy, has been able to reduce deforestation rate and increase its forest cover and associated carbon sink in the terrestrial biosphere. Due to fast growth rate and adaptability to a range of environments, short rotation plantations, in addition to carbon storage, rapidly produce biomass for energy and contribute to reduced greenhouse gas emissions. India has the potential to create additional carbon sinks using marginal lands, while at the same time balancing economic development and environmental concerns.

    Nabuurs, G.J. ; Masera, O. ; Andrasko, K. ; Benetiz-Ponce, P. ; Boer, R. ; Dutschke, M. ; Elsiddig, E. ; Ford-Robertson, J. ; Frumhoff, P. ; Karjalainen, T. ; Krankina, O. ; Kurz, W.A. ; Matsumoto, M. ; Oyhantcabal, W. ; Ravindranath, N.H. ; Sanz Sanchec, M.J. ; Zhang, X. - \ 2007
    In: Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change / Metz, B., Davidson, O.R., Bosch, P.R., Dave, R., Meyer, L.A., Cambridge (UK) and New York (USA) : Cambridge University Press (Climate Change 2007 ) - ISBN 9780521705981 - p. 541 - 584.
    landgebruik - bosbouw - ontbossing - land use - forestry - deforestation
    During the last decade of the 20th century, deforestation in the tropics and forest regrowth in the temperate zone and parts of the boreal zone remained the major factors responsible for emissions and removals, respectively. However, the extent to which the carbon loss due to tropical deforestation is offset by expanding forest areas and accumulating woody biomass in the boreal and temperate zones is an area of disagreement between land observations and estimates by top-down models
    Paradise in a Brazil nut cemetery : sustainability discourses and social action in Pará, the Brazilian Amazon
    Otsuki, K. - \ 2007
    Wageningen University. Promotor(en): Jandouwe van der Ploeg, co-promotor(en): Alberto Arce. - [S.l.] : s.n. - ISBN 9789085046837 - 255
    ontwikkelingsstudies - duurzaamheid (sustainability) - ontbossing - nederzetting - natuurlijke hulpbronnen - hulpbronnenbeheer - etnografie - sociale structuur - gemeenschappen - brazilië - amazonas - sociale processen - development studies - sustainability - deforestation - settlement - natural resources - resource management - ethnography - social structure - communities - brazil - amazonas - social processes
    This book is about sustainable development and deforestation in the Brazilian Amazon. It explores how Amazonian settlers construct their life in a settlement project and how this process accompanies the landscape change in the southeast of Pará State. The book critically examines discourses of sustainable development and natural resource management for the institutionalism and insufficient dealings with the settlers’ everyday practice of forest clearing. The study demonstrates rich social and political life of the settlers in ethnographic details and shows flexible community boundaries of settlement projects. Deforestation and sustainable development in the Amazon cannot be discussed without understanding changeable social and physical spaces from the settlers’ standpoint. This book further elaborates a critical account of development projects and international cooperation programs promoting sustainable development in the Amazon, based on the author’s own experience.
    Forest, institutions, discourses : a discursive-institutional analysis of global forest politics
    Arts, B.J.M. - \ 2006
    Wageningen : Wageningen University & Research centre - 40
    bossen - bosbeleid - politiek - ontbossing - instellingen - openbare redes - forests - forest policy - politics - deforestation - institutions - public speeches
    Economic analysis of deforestation : the case of the gum Arabic belt in Sudan
    Rahim, A. - \ 2006
    Wageningen University. Promotor(en): Ekko van Ierland; Ruerd Ruben, co-promotor(en): Justus Wesseler. - [S.l.] : S.n. - ISBN 9789085044697 - 141
    natuurlijke hulpbronnen - hulpbronnenbeheer - ontbossing - milieuafbraak - economische analyse - arabische gom - Sudan - milieueconomie - natural resources - resource management - deforestation - environmental degradation - economic analysis - gum arabic - Sudan - environmental economics
    Keywords: Gum Arabic; Deforestation; Entry and Exit; Real options Drought; Socio-economic, Oligopoly; Interdependent markets; Stackelberg.The gum arabic belt inSudanoffered in the past an example of how environmental conservation and economic development could be achieved simultaneously as it generates a number of private and social benefits to gum producers and the country as a whole. The most important benefits from the gum based system are income from the gum harvest to the poor farmers and combating large scale desertification in the Sudan-Sahel zone. Over the last few decades, however, the gum belt suffered from increased degradation, gum production decreased andSudanlost its near monopoly position in the gum export market. The main purpose of this study is to obtain a better understanding of the factors underlying the deforestation of the gum belt and the decline in gum production inSudanduring recent years.

    Two important gum arabic producing acacias are found in the gum belt: Acaciasenegal that produces high quality gum and Acacia seyal that produces low quality gum. The analysis in this study focuses mainly on Acaciasenegal and Acacia senegal -based agroforestry system in Kordofan region - a major gum production area inSudan. Various methodological approaches including theoretical and empirical analysis are employed in the study. A micro econometrics technique is used to identify the effect of socio-economic factors assumed to influence the disadoption of gum production. The study merges the real options approach with agroforestry to analyze farmers' investment decision in the choice between three different land use systems (gum agroforestry, gum forestry and agriculture). Moreover a theoretical scheme of Stackelberg model (non-cooperative oligopoly model) is deployed to analyze the competition in the gum export market for high and low quality gum between the (leader)Sudanand the followers (ChadandNigeria). It attempts to investigate the effects of market interventions-such as international subsidies on gum market equilibrium and leader's (Sudan's) long run performance of profits from the gum export.

    The micro-econometric approach used to analyze the determinants of farmers' disadoption of gum production shows that factors which affect the opportunity cost of labor and income from annual crops tend to influence the observed variation in the behavior of adoption practices in gum production. Income from annual crops has a positive effect on continuous adoption of gum agroforestry. This specific result suggests that gum arabic and other agricultural crops (except groundnut because of overlap in harvest time) do not compete but rather complement one another in the household farming economy. Policy measures that aim to improve agricultural production in the region will induce farmers to settle in their village and reduce the seasonal labor migration trend which in turn will increase the availability of labor for gum production.

    The theoretical framework developed using a real options approach aimed to analyze the economic incentives for entry (planting gum tree) and exit (abandoning gum forest) in the gum arabic agroforestry.Monte Carlosimulation shows that higher economic benefit is observed from agricultural production than the gum production. Results also suggest that an increase of about nine to ten times on the average opportunity costs of labor is necessary in order for farmers to further abandon gum arabic production and neglect the gum forest.

    As for the expansion (plantation) of gum forest we analyzed two options: converting idle land into gum forest and converting agricultural land into gum forest. Results show that the incremental average annual benefits of gum agroforestry or forestry systems are above the critical values for converting idle land to a gum arabic forest. This suggests that farmer's could expand gum forest. However, this is not observed, and we suggest two interpretations to explain the observed non-expansion of gum forest into idle lands: scarcity of labor and insecure property rights caused by political instability in the country which discourage long-term investments.

    Furthermore, the current incremental average annual benefits for converting agricultural land to gum arabic agroforestry (forestry) system are found to be below the calculated threshold values needed for the investment. Results suggest that an increase in the prices of gum arabic respectively of about 315 per cent and 775 percent is needed to induce a shift in land use system from continuous agricultural production to gum agroforestry or forestry land use systems respectively.

    The analysis of the competition in the gum export market between the three major gum exporters attempts to assess the best strategy forSudanto pursue in light of the recent changes in the gum market structure and the proposed donor policies of subsidizing gum production in Sub-Saharan Africa. The analysis is based on von Stackelberg model and investigates the effect of different subsidy scenarios. Our result shows that the proportionate increase inSudan's profit is higher when the leader (Sudan) uses a subsidy to promote high quality gum than when it uses the subsidy to promote the low quality gum. In the case of followers (Chad,Nigeria), however, the decision on which quality to promote appears to be sensitive to the levels of own and cross price elasticities. Moreover, the results suggest that it is in the advantage of Sudan, Chad and Nigeria to adopt an export coordination strategy with some side payments to be made by Sudan as compensation for Chad's and Nigeria's lost profits in case they agree to curtail their export of high quality gum.
    Agriculture and climate beyond 2015: a new perspective on future land use patterns
    Brouwer, F.M. ; McCarl, B.A. - \ 2006
    Dordrecht : Springer (Environment & policy vol. 46) - ISBN 9781402040634 - 307
    landgebruik - landbouw - klimaatverandering - broeikasgassen - emissie - bio-energie - ontbossing - land use - agriculture - climatic change - greenhouse gases - emission - bioenergy - deforestation
    Interactions between agriculture, climate and patterns of land use are complex. Major changes in agriculture, and land use patterns are foreseen in the next couple of decades in response to shifts in climate, greenhouse gas management initiatives, population growth and other forces. The book explores key interactions between changes in agriculture, patterns of land use and efforts to reduce greenhouse emissions from agriculture. The volume is based on inter-disciplinary science and policy interactions, exploring the way land use may aid in addressing or be affected by the onset of climate change and alterations in food demand. Future forces shaping land use decisions are examined, and its sensitivity to climate change is highlighted. Patterns of land use and the agricultural role in climate change mitigation are explored. Also, policy and social responses to the new perspectives on future land use patterns are identified. The perspective of the book is beyond the year 2015.
    Land Use, Nature Conservation and the Stability of Rainforest Margins in Southeast Asia
    Gerold, G. ; Fremery, M. ; Guhardja, E. ; Claassen, N. ; Priess, J. ; Rheenen, T. van; Waltert, M. ; Zeller, M. - \ 2004
    Berlin : Springer Science + Business Media (Environmental science ) - ISBN 9783540006039 - 534
    tropische regenbossen - landgebruik - natuurbescherming - ontbossing - bosbestanden - bosbedrijfsvoering - biodiversiteit - zuidoost-azië - tropical rain forests - land use - nature conservation - deforestation - forest resources - forest management - biodiversity - south east asia
    This book contains a selection of contributions presented at an international symposium on "Land Use, Nature Conservation and the Stability of Rainforest Margins in Southeast Asia," in Bogor, Indonesia, October 2002. It highlights the critical issue of rainforest preservation from an interdisciplinary perspective, comprising input from scientists in socio-economic, biological, geographical, agrarian and forestry disciplines.
    Economic Analysis of Urban Fuelwood Demand - The case of Harare in Zimbabwe
    Chambwera, M. - \ 2004
    Wageningen University. Promotor(en): Henk Folmer; Wim Heijman. - Wageningen : Wageningen Universiteit - ISBN 9789085040866 - 222
    milieu - economie - natuurlijke hulpbronnen - brandhout - economische analyse - ontbossing - energiegebruik - relaties tussen stad en platteland - zimbabwe - afrika - environment - economics - natural resources - fuelwood - economic analysis - deforestation - energy consumption - rural urban relations - zimbabwe - africa

    This study carries out an economic analysis of the demand for fuelwood in urban areas using Harare, the capital city of Zimbabwe, as a case study. The demand for fuelwood in urban areas is one of the causes of several environmental and health problems in Africa, where the up to 90% of energy requirements are met by wood.
    The study first develops an energy mix model as the conceptual framework, using the energy ladder hypothesis as a starting point. The energy mix model is based on the fact that in any one period, urban households use multiple sources of energy. Consumer theory is used to underpin this reality, and link it to the analyses that fo11ow. System of demands is used in the empirical analysis, using the Almost Ideal Demand System (AIDS model), in linear approximate form, as the empirical model, incorporating the effects of other household characteristics in addition to income and prices. A multi-stage budgeting process is used the analyses, which assumes that households first decide how much of their total expenditures to a11ocate to energy, among other household goods. At the second stage, they decide how much of their total energy outlays to a11ocate to specific fuels. Empirical analyses are carried out using household survey data co11ected in Harare from a sample of 500 households.
    The share of energy in total expenditure is shown to be 13% and 11% for electrified and unelectrified households respectively. For a11 households, total energy expenditure increases with total household expenditure. Other factors that explain household differences in total energy expenditure shares are household size, energy-using appliances owned, the number of rooms owned, the number of families living together at the same property and the level of education of the household head. The main sources of energy are electricity, firewood and kerosene, accounting for 73%, 14% and 13% of total energy expenditure respectively. Electrified households spend 81 %, 9% and 10% of their total energy outlays on these fuels respectively, while unelectrified households spend 55% and 45% of their total energy budgets on firewood and kerosene respectively. Among electrified households, the share of the energy budget a11ocated to fuelwood increases as household size, the number of households living together at the same property, the number of rooms being used by a household, the prices of electricity and kerosene increase. It decreases with total household expenditure, the educational level of the household head, the value of energy appliances, the square of household size and the price of fuelwood. Among unelectrified households, the share of fuelwood in the energy budget increases with total energy expenditure, the value of appliances, household size, the educational level of the household head and the price of kerosene. It decreases with households living together at the same property, the square of household size, the number of rooms used and the price of fuelwood. The shares of other fuels estimated in the same system of equations respond in different ways to these variables. The main policy implication of the findings is that fuelwood demand management is best approached by taking the whole energy urban system into account. The specific management options are pointed to by the response of demand to the different demand variables. Total electrification will not eliminate urban fuelwood demand if other demand variables are not attended to.
    Slash and burn agriculture in the humid forest zone of southern Cameroon
    Kanmegne, J. - \ 2004
    Wageningen University. Promotor(en): Lijbert Brussaard; E.M.A. Smaling. - Wageningen : s.n. - ISBN 9789051130706 - 184
    inga edulis - zwerflandbouw - gewasopbrengst - wormhoopjes - landgebruik - verbeterde braak - ontbossing - voedingsstoffen - humide klimaatzones - bossen - kameroen - inga edulis - shifting cultivation - crop yield - worm casts - land use - improved fallow - deforestation - nutrients - humid zones - forests - cameroon
    Keywords: crop yields, earthworm cast, Inga edulis , land use, nutrient flows, nutrient stocks, nutrient management, slash and burn

    A field study was conducted on acid soils in the humid forest zone of Southern Cameroon, to characterize the traditional slash-and-burn land uses, assess the major effects of land use change on soil nutrient stocks, flows, and soil biological quality, and to explore alternatives for sustainable land management. The typical land use chronosequence in the area after forest felling includes essep (cucumber-based), banana, and afup (groundnut/cassava-based), and is interrupted by short (after banana) and long (after afup) fallows. Moreover, farmers have cocoa farms where many shade trees are kept. Yield declines in farmers' fields were attributed to diseases and weed infestation (56%) and soil properties (44%).  Burning is practiced prior to essep, and prior to afup. It reduces the weed seed-bank, cleans the field and improves short-term soil fertility, but, together with changing land use, it strongly reduces standing biomass, carbon and nutrient stocks in the vegetation. The forest carbon stock decreased from 199 Mg.ha -1 to 102 Mg.ha -1 in essep , and to 64 Mg.ha -1 in banana farm. Nutrient stocks showed the same trend, but Chromolaena short fallow, that followed banana, recovered most of the P. The cocoa plantation had 53 % of the carbon stocks of the original forest. Soil carbon stock was less affected than vegetation stocks.Burning increased P, K, Ca and Mg available stocks in essep and afup . Lowest 'system' C and N occurred in afup , which is followed by a long fallow to restore soil fertility. The nutrient balance at farm level was strongly negative, i.e., -72.6 kg N, -4.8 kg P and -38.2 kg K ha -1 yr -1 , showing its 'no external input' character, where food and wood are derived from natural stocks. Major losseswere dueto burning, leaching and the non-recycling of farm residues. Only the cocoa farm had a positive nutrient balance: +9.6 kg N, +1.4 kg P and +7.6 kg K ha -1 .yr -1 , as burning is absent, leachingmodest,and deep capture by shade trees providing inputs to the productive system. Simple scenarios showed that recycling farm residues is able to redress the P and K balance, and avoiding burning could even turn the entire nutrient balance positive. Burning also negatively affected earthworm density and casting activities. Up to 95% loss in density was recorded, and casting activity was inhibited during 14 and 19 months in land use systems following afup and essep respectively. Inga fallow proved to favour rapid and intensive casting just as the forest ecosystem. Total cast production was: 5.9 Mg.ha -1 in afup , 3.2 Mg.ha -1 in forest and Inga , and 2.9 Mg.ha -1 in essep after two years, but although the casts were richer in nutrients than the topsoil, the nutrients recycled from casts alone were insufficient for sustained crop production.   Inga edulis was found to be a suitable planted fallow, providing several benefits to farmers and follow-up crops.   Inga fallows produce more biomass (between 44.5 and 62 Mg ha -1 ), and accumulate more C and N than natural fallow. Maize following Inga fallow yielded 800 to 2200 kg.ha -1, against a mere 200-400 kg.ha -1 after natural fallow.  Burning Inga residues gave ngon (cucumber) productionof 300 kg.ha -1 ,which is similar to yields obtained in essep following natural forest. Mulching instead of burning, however, only gave50 kg.ha -1. An innovative on-farm approach was used in the development and implementation of planted fallows, ensuring highadoption. Inga edulis planted fallow can play a leading role among strategies to fight the gradual process of land degradation in the land use chronosequence, providing wood and fruits, and mimicking the natural forest to a considerable extent.
    The use of models to assess the impact opf land use change on ecological processes: case-studies of deforestation in south-east Asia
    Verburg, P.H. ; Veldkamp, A. ; Engelsman, W. ; Zalinge, R. van; Mensvoort, M.E.F. van; Overmars, K.P. - \ 2004
    In: Land use, nature conservation anf the stability of rainforest margins in southeast Asia / Gerold, G., Fremerey, M., Guhardja, E., Berlin Heidelberg : Springer - ISBN 9783540006039
    landgebruik - bosecologie - ontbossing - modellen - agro-ecologie - land use - forest ecology - deforestation - models - agroecology
    A land use change model, CLUE-s, is used for two applications in South-east Asia to illustrate the potential value of land use change simulations for ecological impact assessments
    Expansion of cattle ranching in Latin America: A farm economic approach for analyzing investment decisions
    Roebeling, P.C. - \ 2003
    Wageningen University. Promotor(en): Arie Kuyvenhoven, co-promotor(en): Ruerd Ruben. - Wageningen : S.n. - ISBN 9789058088604 - 150
    economische ontwikkeling - landbouwontwikkeling - extensieve slachtveehouderij - rundvee - extensieve veehouderij - weiden - rundvleesproductie - overheidsbeleid - land - speculatie - milieuafbraak - ontbossing - hulpbronnenbeheer - latijns-amerika - investeringsbeslissingen - economic development - agricultural development - ranching - cattle - extensive livestock farming - pastures - beef production - government policy - land - speculation - environmental degradation - deforestation - resource management - latin america - investment decisions

    It is generally recognized that cattle ranching in Latin America occupies the major part of the agricultural area, that pasture expansion in favor of cattle ranching is the principal cause of deforestation, and that the conversion of forest into pasture has important environmental consequences. Within the so called 'cattle ranching debate', the expansion of cattle ranching is attributed to the characteristics of cattle ranching, the increased demand for beef products, government policies, land speculation, and resource degradation. Most of the arguments put forward in this debate are, however, qualitative and incomplete in a number of respects. The objective of this study is to obtain an improved understanding of investment and resource use decisions of cattle ranchers in Latin America. To this end, we develop an analytical framework that enables the quantitative appraisal of factors that are considered to have contributed to the expansion of cattle ranching since the 1960's. Illustrative examples are given for cattle ranchers in the Atlantic Zone of Costa Rica.

    The increase in Latin American beef production is often explained by the increased demand for beef products, though was accompanied by a considerable decrease in beef prices since the mid 1970's. This study demonstrates that investments in land are deflated due to expected decreases in beef prices, though inflated due to expected fluctuations in beef prices. For a risk-neutral cattle rancher in Costa Rica it is shown that the inflationary effect resulting from fluctuations in beef prices outweighs the deflationary effect resulting from expected decreases in beef prices, with subsequent consequences for deforestation.

    The role of land speculation as a contributor to deforestation is highly debated, and largely comes down to whether or not land prices tend to rise over time. In this study it is shown that variability in land prices alone is a sufficient condition for land speculation and inflated levels of investment in land, with subsequent consequences for deforestation. Furthermore, it is shown that increasing land prices only lead to inflated levels of investment in land and deforestation if the land sales price increases relative to the land purchase price. The opposite occurs when the land purchase as well as the land sales price increase.

    The role of resource degradation on the expansion of cattle ranching is sparsely and mostly qualitatively dealt with in literature. This study shows that resource degradation provides cattle ranchers the incentive to continuously convert forest into pasture, as forest areas form an important source of fertility for cattle ranchers operating at the agrarian frontier. Fertilizer does not form an economically viable alternative for soil fertility, as current fertilizer prices and application costs per kilogram are far higher than the cost per kilogram of soil fertility obtained through deforestation.

    The presented farm-economic approach forms a contribution to current cattle ranching modeling approaches, especially in the Latin American context. Contrary to existing cattle ranching models, that invariably assume a fixed farm size and that do not consider uncertainty or resource degradation, the cattle rancher is considered a profit maximizer who uses land as a productive resource as well as an investment object. It is shown that this approach facilitates the analysis of resource use and investment decisions of cattle ranchers, thereby taking farmer objectives, production possibilities and resource constrains, as well as the relevant economic and policy environment into account.

    Criteria, potentials and costs of forestry activities to sequester carbon within the framework of the clean development mechanism
    Waterloo, M.J. ; Spiertz, P.H. ; Diemont, W.H. ; Emmer, I. ; Aalders, E. ; Wichink Kruit, R.J. ; Kabat, P. - \ 2003
    Wageningen : Alterra (Alterra-rapport 777) - 136
    koolstof - kooldioxide - fixatie - emissie - bossen - bebossing - ontbossing - klimaatverandering - kostenanalyse - sociale economie - opslag - duurzaamheid (sustainability) - bosbedrijfsvoering - koolstofvastlegging - carbon - carbon dioxide - fixation - emission - forests - afforestation - deforestation - climatic change - cost analysis - socioeconomics - storage - sustainability - forest management - carbon sequestration
    Forest activities in developing countries can be used to sequester carbon for gaining emission reductions within the Clean Development Mechanism of the Kyoto Protocol. This study has assessed the potentials and costs for carbon sequestration through afforestation, reforestation and deforestation activities and how these are affected when certain criteria for eligibility are applied. The criteria address issues of additionality, permanence, socio-economic and environmental sustainability, compliance and verification, which are of major importance for the successful implementation of forestry projects in the Clean Development Mechanism. Application of the criteria results in a substantial decrease in the carbon sequestration potential and an increase in the project costs.
    Land cover and the climate system
    Hutjes, R.W.A. ; Kabat, P. ; Dolman, A.J. - \ 2003
    In: Global environmental change and land use / Dolman, A.J., Verhagen, A., Rovers, C.A., Dordrecht : Kluwer - ISBN 9781402013461 - p. 73 - 110.
    landgebruik - vegetatie - landbouwklimatologie - klimaatverandering - bodemwater - ontbossing - woestijnvorming - land use - vegetation - agroclimatology - soil water - deforestation - desertification - climatic change
    The Amazon region: tropical deforestation, biogeochemical cycles and the climate
    Kabat, P. ; Andreae, M.O. ; Silva-Dias, M.A. ; Veraart, J.A. ; Brink, N.J. - \ 2003
    Bilthoven : RIVM (Dutch National Research Programme on Global Air Pollution and Climate Change 410200125) - ISBN 9789058510983 - 108
    luchtverontreiniging - klimaatverandering - amazonia - ontbossing - biogeochemie - air pollution - climatic change - amazonia - deforestation - biogeochemistry
    The biogeochemical cycling of carbon, water, energy, aerosols, and trace gases in the Amazon Basin, and the interactions between deforestation, rainfall and climate were all investigated in this programme as a part of an integrated cluster of inter-linked and complementary research projects. These include LBA-EUSTACH (EUropean Studies on Trace gases and Atmospheric CHemistry as a contribution to the Large-scale Biosphere-Atmosphere experiment in Amazonia), LBA TRMM (Tropical Rainfall Measuring Mission), LBA WET AMC (LBA Wet Season Atmospheric Mesoscale Campaign) and LBA Project "The Effects of Tropical Deforestation on Climate" under the Dutch National Research Programme on Global Air Pollution and Climate Change. All these projects were integrated under the overall research objective of the LBA (Large Scale Biosphere Atmosphere Experiment in Amazon), and their set up enabled a full research synergy by for example the use of joint field research sites and other collaborative facilities. We present an overview of the design of these projects, the measurement sites and methods, and some preliminary research results.
    Methodology for simulating the spatial dynamics of land use change in forest gringes
    Veldkamp, A. ; Verburg, P.H. - \ 2002
    In: Land use, nature conservation, and the stability of rainforest margins in Southeast Asia, proceedings Bogor - p. 131 - 134.
    landgebruik - bossen - ontbossing - modellen - filippijnen - land use - forests - deforestation - models - philippines
    Forestland: its dynamics, disorganised uses and planning in South Kalimantan, Indonesia
    Indrabudi, H. - \ 2002
    Wageningen University. Promotor(en): R.A.A. Oldeman; H. Simon. - S.l. : S.n. - ISBN 9789058087447 - 187
    bossen - landgebruik - bosbouw - ontbossing - plattelandsgemeenschappen - bosbedrijfsvoering - ruimtelijke ordening - kalimantan - indonesië - forests - land use - forestry - deforestation - rural communities - forest management - physical planning - kalimantan - indonesia

    This study was aimed at analysing land cover and land use dynamics, and at identifying and evaluating the driving forces behind deforestation, by relating population dynamics, village distribution patterns and socio-economic indicators with spatial aspects of land cover changes. It also aimed at knowing the conditions of the local people, their opinions and aspirations regarding conservation. A land re-allocation model for agricultural land and protection forest, as an approach to solving the problem was established

    Forestland dynamics and forestland fragmentation, which showed a continuing decrease in forestland, were studied using two land allocation plans. Decreasing role of the Forestry Agency was also described, as one of the main actors involved in the forestland use planning process. Their strategic factors were identified, and a possible strategy to counter the problems currently faced by the Forestry Agency was formulated. It was concluded with a concept for a forestland use classification by proposing more factors to be considered, based on the principles of economic viability, social acceptance and environmental soundness.

    Land Speculation as a Cause of Deforestation : The Role of Cattle Ranching in the Humid Tropics of Costa Rica
    Roebeling, P.C. ; Hendrix, E.M.T. - \ 2002
    In: Proceedings : Risk and Uncertainty in Environmental and Resource Economics, Wageningen, 2002 / van Ierland, E.C., Weikard, H.P., Wesseler, J., Wageningen : Env. Economics and Natural Resources Group - p. 10 - 10.
    ontbossing - overdrachten van grond - rundveeteelt - investering - besluitvorming - grondprijzen - onzekerheid - costa rica - deforestation - land transfers - cattle farming - investment - decision making - land prices - uncertainty - costa rica
    This paper examines the effect of land speculation on investment decisions by cattle ranchers in Latin America, and the subsequent consequences for deforestation under varying levels of land price uncertainty and interest rate subsidy. Based on the Neoclassical investment theory, a stochastic reversible investment model with adjustment costs is developed in which land prices are modeled as a geometric Brownian motion. Analytical results indicate that: 1) the optimal rate of investment is dependent on the price of land at a specific moment in time, 2) the value of the farm increases with the variance in land prices due to speculative returns from land, and 3) the maximum farm size attained over time will be larger, the larger the variance in land prices. For the numerical example of an average cattle rancher in the Atlantic Zone of Costa Rica, it is shown that lower fluctuations in land prices lead to a reduction in these speculative returns, as well as a reduction in the maximum farm size attained over time. This effect is further reinforced in combination with lower interest rate subsidies. Consequently, it can be concluded that variability in land prices alone is a sufficient condition for land speculation and subsequent deforestation of agrarian frontier areas by cattle ranchers in the Atlantic Zone of Costa Rica, and that this deforestation is further promoted by subsidized livestock credit
    Chloroplast DNA variation of oaks in western Central Europe and genetic consequences of human influences
    König, A.O. ; Ziegenhagen, B. ; Dam, B.C. van; Csaikl, U.M. ; Coart, E. ; Degen, B. ; Burg, K. ; Vries, S.M.G. de; Petit, R.J. - \ 2002
    Forest Ecology and Management 156 (2002)1-3. - ISSN 0378-1127 - p. 147 - 166.
    biodiversiteit - biogeografie - eik - genetica - ontbossing - populatiebiologie - Europa - België - Nederland - Luxemburg - Duitsland - Tsjechië - Oostenrijk
    Oak chloroplast DNA (cpDNA) variation was studied in a grid-based inventory in western Central Europe, including Belgium, The Netherlands, Luxembourg, Germany, the Czech Republic, and the northern parts of Upper and Lower Austria. A total of 2155 trees representing 426 populations of Quercus robur L. and Q. petraea (Matt.) Liebl. were screened for polymorphism in up to four PCR-amplified cpDNA fragments. Eleven haplotypes belonging to four lineages were detected; these lineages were formerly restricted to glacial refugia in the Iberian Peninsula, the Apennine Peninsula and the Balkan Peninsula. The haplotypes originating from the Apennines are particularly well represented in the study region, but there is also a significant contribution from the other refugia, which explain the high overall level of cpDNA diversity. The strong human impact in western Central Europe during the past centuries, which has resulted in the clearance of most forests, was followed by reforestation, sometimes involving seed transfers. Despite this strong human impact, broad geographic patterns of lineages and haplotypes could still be detected. To evaluate further the consequences of the former human activities on the present day oak cpDNA genetic structure, four regions where increasingly strong human impact was anticipated (ranging from hilly regions in southern Germany to roadsides plantations in The Netherlands) were selected. There, a comparison of the levels of intrapopulation cpDNA diversity and spatial structuring was made. Over the whole area, within stand diversity was significantly higher in Q. robur than in Q. petraea (h[sub]S = 0.24 vs. 0.16). Since total diversity is identical for both species, this results in a significantly lower level of fixation for Q.robur than for Q. petraea (G[sub]ST = 0.68 vs. 0.79). The analyses also reveal a decrease of fixation with increasing human impact on oak populations. The Dutch roadside plantations (Q. robur) exhibit a very low level of fixation (GST = 0.28) as comparedto Q. petraea in southern Germany (GST=0.91). The significance of the spatial genetic structure was tested using geostatistical methods. For the complete data set, a strong spatial genetic structure is confirmed, with higher than average genetic similarities between populations distant from up to 270 km, whereas there is no spatial structure in the roadside plantations in The Netherlands or in the northern German lowlands. These results should help to differentiate introduced from autochthonous populations, and provide a framework for the identification of the geographic origin of seed lots.
    Polarimetric data for tropical forest monitoring : studies at the Colombian Amazon
    Quiñones Fernández, M. - \ 2002
    Wageningen University. Promotor(en): R.A. Feddes; D.H. Hoekman. - Wageningen : Tropenbos International - ISBN 9789058087508 - 184
    tropische bossen - monitoring - remote sensing - polarimetrie - radar - cartografie - ontbossing - biomassa - amazonia - colombia - tropical forests - monitoring - remote sensing - polarimetry - radar - mapping - deforestation - biomass - amazonia - colombia

    An urgent need exists for accurate data on the actual tropical forest extent, deforestation, forest structure, regeneration and diversity. The availability of accurate land cover maps and tropical forest type maps, and the possibility to update these maps frequently, is of great importance for the development and success of monitoring systems. For areas like the Amazon the use of optical remote sensing systems as the source of information, is impeded by the permanent presence of clouds that affect the interpretation and the accuracy of the algorithms for classification and map production. The capabilities of radar systems to acquire cloud free images and the penetration of the radar waves into the forest canopy make radar systems suitable for monitoring activities and provide additional and complementary data to optical remote sensing systems. Information regarding forest structure, forest biomass, and vegetation cover and flooding can be associated with radar images because of the typical wave-object interaction properties of the radar systems.

    In this thesis new algorithms for the classification of radar images and the production of accurate maps are presented. The production of specific maps is studied by applying the developed algorithms to two different study areas in the Colombian Amazon. The first site, San José del Guaviare, is a colonisation area with active deforestation activities and dynamic land cover change. The second area is a pristine natural forest with high diversity of landscapes.

    A detailed statistical description of the polarimetric AirSAR data is made in terms of backscatter (gamma values), polarimetric phase difference and polarimetric correlation. This approach allows a better interpretation of physical backscatter mechanisms important for interpretation of images in relation to ground parameters. Theoretical cumulative probability density distributions (pdf) are used to describe the mean field values and the standard deviation for a class. A Gausian distribution is used to describe the field average gamma values; a circular Gausian distribution is used to describe the field average HH-VV phase difference and a Beta distribution is used to described the field average HH-VV phase correlation. The accuracy of the estimation of the field-averaged values depends on the level of speckle, i.e. number of independent looks. This effect is included in the calculation of the pdf's and therefore can be simulated.

    For the Guaviare site the classification algorithm is used to assess the AirSAR data in the production of a land cover type map. Classification accuracies are calculated for different combinations of bands and level of speckle. An accuracy of 98.7% was calculated for a map when combining L-HV and P-RR polarisations. Confusion between classes are studied to evaluate the use of radar bands for monitoring activities, e.g. loss of forest or detection of new deforested areas. In addition a biomass map is created by using the empirical relationship between the combination of the same radar bands and the biomass estimations from 28 plots as measured in the field. The agreement of the biomass map with the land cover map is used to evaluate the biomass classification.

    For the Araracuara site the classification algorithm is used to assess the use of polarimetric data for forest structural type mapping and indirect forest biophysical characterisation. 23 field-measured plots used for forest structural characterisation are used to assess the accuracy of the classification. A new SAR derived legend is more suitable for the SAR map allowing better physical interpretation of results. A method based on iterated conditional modes is introduced to create maps from the classified radar images, increasing in most of the cases the accuracy of the classification. The structural type map with 15 classes can be classified with accuracies ranging from 68% to 94% depending on the classification and the mapping approach. The relationship between forest structure and polarimetric signal properties is studied in detail by using a new decomposition of polarimetric coherence, based on a simple physical description of the wave-object interactions. The accuracy of the complex coherence is described using the complex Wishart distribution. In addition for the same area, a biomass map is created using the previous structural type characterisation as the basis for the classification, overcoming problems as the well know radar signal saturation.

    The possibilities and restrictions of creating biomass maps with AirSAR polarimetric images are deeply investigated. Two different approaches are proposed depending on the terrain conditions. A theoretical exploration on the physical limits for radar biomass inversion is made by using a new interface model, called LIFEFORM that describes the layered tropical forest in terms of scatterers. The UTARTCAN scattering model is used to analyse the effect of flooding, forest structure and terrain roughness in the biomass inversion.

    Poverty alleviation and wise use of peatlands in Indonesia
    Diemont, W.H. ; Joosten, H. ; Mantel, S. ; Murdiyarso, D. ; Norrordwijk, M. van; Rieley, J.O. ; Veldsink, J.W. ; Verhagen, A. ; Wakker, E. ; Wind, J. ; Setiadi, B. ; Limin, S.H. - \ 2001
    International peat journal / International Peat Society (2001)11. - ISSN 0782-7784 - p. 79 - 87.
    veengronden - landgebruik - landbouwproductie - indonesië - duurzaamheid (sustainability) - ontbossing - armoedebestrijding - duurzaamheid - landbouw - ontwikkelingssamenwerking - Azië - peat soils - deforestation - land use - agricultural production - sustainability - indonesia
    This paper focusses on the conservation of forest resources in Indonesia. Oil palm plantations, but also other plantation crops, have the economic potential to provide income, in a stage of development where the income generated from forest resources will decrease in most local governments in the near future
    Mapping and monitoring forest remnants : a multiscale analysis of spatio-temporal data
    Carvalho, L.M.T. de - \ 2001
    Wageningen University. Promotor(en): S.M. de Jong; A.K. Skidmore; J.G.P.W. Clevers. - S.l. : S.n. - ISBN 9789058085450 - 138
    bossen - cartografie - monitoring - geografische informatiesystemen - ontbossing - remote sensing - forests - mapping - monitoring - geographical information systems - deforestation - remote sensing
    KEYWORDS : Landsat, time series, machine learning, semideciduous Atlantic forest, Brazil, wavelet transforms, classification, change detection

    Forests play a major role in important global matters such as carbon cycle, climate change, and biodiversity. Besides, forests also influence soil and water dynamics with major consequences for ecological relations and decision-making. One basic requirement to quantify and model these processes is the availability of accurate maps of forest cover. Data acquisition and analysis at appropriate scales is the keystone to achieve the mapping accuracy needed for development and reliable use of ecological models.

    The current and upcoming production of high-resolution data sets plus the ever-increasing time series that have been collected since the seventieth must be effectively explored. Missing values and distortions further complicate the analysis of this data set. Thus, integration and proper analysis is of utmost importance for environmental research. New conceptual models in environmental sciences, like the perception of multiple scales, require the development of effective implementation techniques.

    This thesis presents new methodologies to map and monitor forests on large, highly fragmented areas with complex land use patterns. The use of temporal information is extensively explored to distinguish natural forests from other land cover types that are spectrally similar. In chapter 4, novel schemes based on multiscale wavelet analysis are introduced, which enabled an effective preprocessing of long time series of Landsat data and improved its applicability on environmental assessment.

    In chapter 5, the produced time series as well as other information on spectral and spatial characteristics were used to classify forested areas in an experiment relating a number of combinations of attribute features. Feature sets were defined based on expert knowledge and on data mining techniques to be input to traditional and machine learning algorithms for pattern recognition, viz . maximum likelihood, univariate and multivariate decision trees, and neural networks. The results showed that maximum likelihood classification using temporal texture descriptors as extracted with wavelet transforms was most accurate to classify the semideciduous Atlantic forest in the study area.

    In chapter 6, a multiscale approach to digital change detection was developed to deal with multisensor and noisy remotely sensed images. Changes were extracted according to size classes minimising the effects of geometric and radiometric misregistration.

    Finally, in chapter 7, an automated procedure for GIS updating based on feature extraction, segmentation and classification was developed to monitor the remnants of semideciduos Atlantic forest. The procedure showed significant improvements over post classification comparison and direct multidate classification based on artificial neural networks.

    The economics of nature : managing biological assets
    Kooten, G.C. van; Bulte, E.H. - \ 2000
    Malden, Mass. [etc.] : Blackwell Publishers - ISBN 9780631218944 - 512
    natuurlijke hulpbronnen - hulpbronnenbeheer - economie - investering - kapitaal - milieubeheer - welvaartseconomie - taxatie - duurzaamheid (sustainability) - natuurbescherming - bedreigde soorten - biodiversiteit - bosbedrijfsvoering - ontbossing - natural resources - resource management - economics - investment - capital - environmental management - welfare economics - valuation - sustainability - nature conservation - endangered species - biodiversity - forest management - deforestation
    The Economics of Nature Management takes a portfolio management perspective on the worldwide deterioration of the natural environment. For many emerging countries, nature conservation boils down to the purely economic decision of "investing" limited funds in nature potentially at the expense of investing in other necessary imperatives such as education or infrastructure. As a result, the authors see the function of the book as twofold. First, to measure environmental services and biological assets and second it demonstrates how it applies the economic theory of nature management through case studies.
    Birds on fragmented islands : persistence in the forests of Java and Bali
    Balen, S. van - \ 1999
    Agricultural University. Promotor(en): H.H.T. Prins. - S.l. : S.n. - ISBN 9789058081506 - 181
    vogels - dierecologie - populatiedynamica - bedreigde soorten - bescherming - natuurbescherming - habitats - ontbossing - bossen - overleving - java - bali - birds - animal ecology - population dynamics - endangered species - protection - nature conservation - habitats - deforestation - forests - survival - java - bali

    This study describes, analyses and provides suggestions for the amelioration of the impact of age-long deforestation on the distribution of forest birds on the islands of Java and Bali (Indonesia). The first section deals with colonisation and extinction processes of forest birds in a number of remaining forest patches on Java. In the regenerating forest of the Krakatau Islands colonisation and extinction of land birds appear to follow vegetation succession, and therefore seem to affect the monotonic change as predicted by MacArthur & Wilson's equilibrium theory of island biogeography.

    Extinction of forest birds in the Bogor botanical gardens appears to mirror closely the condition of bird communities in the surroundings of this isolated woodland patch. Distribution patterns of forest birds across 19 highly scattered forest fragments ranging from six to 50,000 hectares show clearly that the ability of birds to survive in surrounding habitat reflects the ability to survive in these patches. To show this, four ecological groups of forest birds have been distinguished: (1) forest interior birds, (2) forest edge birds, (3) woodland birds and (4) rural/urban birds. Nestedness patterns (in which species are found in all fragments larger than the smallest one in which it occurs) are found to be strongest for species restricted to forest interior and edge, weaker for secondary growth, and weakest for rural and urban bird species. A large number of forest interior species appear to be absent from most patches smaller than 10,000 ha, and most are entirely absent from forest patches smaller than 100 ha.

    In the second section of this thesis the conservation status of three globally threatened, high-profile birds is analysed. The endemic, endangered Javan hawk-eagle Spizaetus bartelsi , traditionally considered amongst the most vulnerable forest dwellers, appears to survive in 137-188 breeding pairs in often small and isolated rainforest patches; its survival is explained by (a) juvenile dispersal capabilities, (b) broader niche widths and (c) rather opportunistic feeding. Partly protected by local taboos on hunting, the vulnerable green peafowl Pavo muticus has survived many centuries of human pressure; nowadays at least 1000 birds are scattered across numerous subpopulations. The wild population of the endemic, critically threatened endemic Bali starling Leucopsar rothschildi collapsed since its discovery in 1910 to near extinction in 1990, due to habitat loss and popularity amongst bird-keepers world-wide; despite various conservation measures (captive breeding, awareness programmes, etc.) an intricate web of socio-economic factors prevents the species from emerging from this precarious situation.

    Bosuitbreiding in Nederland ligt niet op schema
    Edelenbosch, N.H. - \ 1997
    Nederlands Bosbouwtijdschrift 69 (1997)5. - ISSN 0028-2057 - p. 231 - 236.
    bosbouw - weiden - bossen - landbouwgrond - relaties - ontbossing - bebossing - landbouwstatistieken - oppervlakte (areaal) - nederland - forestry - pastures - forests - agricultural land - relationships - deforestation - afforestation - agricultural statistics - acreage - netherlands
    Economics of timber plantations on CO2-emissions in the Netherlands.
    Slangen, L.H.G. ; Kooten, G.C. van; Rie, J.P.P.F. van - \ 1997
    Tijdschrift voor sociaalwetenschappelijk onderzoek van de landbouw 12 (1997)4. - ISSN 0921-481X - p. 318 - 333.
    broeikaseffect - opwarming van de aarde - bosbouw - weiden - bossen - landbouwgrond - relaties - ontbossing - bebossing - overheidsbeleid - landbouwbeleid - agrarisch recht - nederland - greenhouse effect - global warming - forestry - pastures - forests - agricultural land - relationships - deforestation - afforestation - government policy - agricultural policy - agricultural law - netherlands
    Met een kosten-batenanalyse wordt nagegaan in welke mate bebossing van landbouwgronden in Nederland een kostenefficiente methode kan zijn om de CO2-concentratie te verlagen
    Essays in economics of renewable resources
    Bulte, E.H. - \ 1997
    Agricultural University. Promotor(en): H. Folmer; W.J.M. Heijman. - S.l. : Bulte - ISBN 9789054856993 - 283
    duurzaamheid (sustainability) - natuurlijke hulpbronnen - hulpbronnengebruik - bescherming - herstel - milieu - kwaliteit - controle - verontreinigingsbeheersing - milieubeheer - bosbouw - weiden - bossen - landbouwgrond - relaties - ontbossing - bebossing - vis vangen - visserij - economie - tropen - nationaal vermogen - sustainability - natural resources - resource utilization - protection - rehabilitation - environment - quality - control - pollution control - environmental management - forestry - pastures - forests - agricultural land - relationships - deforestation - afforestation - fishing - fisheries - economics - tropics - national wealth

    In dit proefschrift neem ik een aantal onderwerpen die betrekking hebben op de economische theorie van beheer van natuurlijke hulpbronnen onder de loep. Voorbeelden van natuurlijke hulpbronnen zijn visvoorraden, bossen en olie. Het onderzoeksveld is breed en biedt keuze uit een scala aan onderwerpen, ieder met zijn eigen problemen, eigenaardigheden en interessante aspecten. Aangezien de afzonderlijke hoofdstukken van dit proefschrift afgesloten worden met een concluderende en samenvattende sectie, zal ik deze samenvatting kort houden.

    De hoofdstukken 1 en 2 betreffen een inleidend literatuuronderzoek. In hoofdstuk 1 wordt het onderzoeksveld afgebakend en worden enkele basisbegrippen besproken. Twee centrale thema's zijn "duurzaamheid" en "efficientie". Duurzaamheid heeft betrekking op gelijke toegang tot natuurlijke hulpbronnen door verschillende generaties. Efficiëntie betekent het (intertemporeel) maximaliseren van een doelfunctie. Het maximaliseren van "de winst of "het nut voor de samenleving" zijn veel gebruikte voorbeelden van dergelijke functies. Na de Earth summit in Rio de Janeiro in 1992 zou "duurzaamheid" wellicht het belangrijkste thema van de twee dienen te zijn, maar er bestaat in de literatuur veel verschil van inzicht over de exacte interpretatie van dit begrip. De interpretatie is subjectief en onder andere afhankelijk van de inschatting van de toekomstige substitutie-mogelijkheden tussen de verschillende productiefactoren (bijvoorbeeld tussen natuurlijk en fysiek kapitaal), en van de mogelijkheden die in de toekomst door technologische vooruitgang geboden zullen worden.

    De interpretatie van efficiëntie is helder, en de mainstream van de neoklassieke economen is traditioneel gericht op dit thema. (Van meer recente aard zijn modellen waarin de beide thema's gecombineerd worden.) De meeste hoofdstukken in dit proefschrift gaan in de eerste plaats over het efficiënt gebruik van (vernieuwbare) natuurlijke hulpbronnen.

    Het exploiteren van een natuurlijke hulpbron heeft invloed op de mogelijkheden voor toekomstig gebruik van deze voorraad. In geval van mijnbouw, bijvoorbeeld, gaat de huidige extractie van ertsen ten koste van grondstofwinning in de toekomst. Dit impliceert dat bij het delven van een eenheid erts, in aanvulling op de pure extractiekosten, rekening moet worden gehouden met de zogenaamde opportunity costs . In dit verband wordt met opportunity costs bedoeld de mogelijke baten die de eenheid erts in de toe komst had kunnen opleveren. Deze "extra" kosten verlagen de optimale hoeveelheid die geëxploiteerd dient te worden. Een belangrijke regel voor efficiënt gebruik van een niet-vernieuwbare hulpbron, zoals olie of steenkool, is dat onder bepaalde voorwaarden de groeivoet van de zogenaamde rent van de hulpbron (gedefinieerd als het verschil tussen de prijs en de marginale exploitatiekosten) gelijk moet zijn aan de interestvoet. Als deze regel opgaat zijn eigenaren van een hulpbron indifferent tussen huidige en toekomstige extractie: het rendement van het aanhouden van een voorraad van een bepaal
    de hulpbron is even hoog als het rendement van exploiteren en het verdiende geld vervolgens elders investeren of op de bank zetten. Dit is de bekende Hotelling regel.

    Voor efficiënt gebruik van hulpbronnen die zichzelf binnen een redelijke termijn kunnen vernieuwen, zoals een voorraad vis of een bos, moet de Hotelling regel aangepast worden. In de economie van dit soort hulpbronnen worden economische principes gecombineerd met biologische groeimodellen. Met behulp van bosbouwmodellen kan dan bijvoorbeeld de optimale omlooptijd van een gelijkjarig bos berekend worden. Met behulp van visserijmodellen wordt de optimale visstand in een bepaald gebied berekend. Het afzien van oogsten, bijvoorbeeld door een hoeveelheid bomen nog een jaar te laten groeien of door de jaarlijkse vangst van een bepaalde vissoort te verlagen, kan geïnterpreteerd worden als "investeren" in de hulpbron. Omgekeerd geldt dat oogsten gelijk staat aan desinvesteren. In hoofdstuk 2 van dit proefschrift wordt door middel van een literatuurstudie ingegaan op deze materie en op verwante zaken als eigendomsrechten (immers, wie wil investeren in een hulpbron als niet duidelijk is of de toekomstige baten toevallen aan hemzelf?) en de rol van overheidsbeleid.

    Hoofdstuk 3 en 4 zijn gewijd aan tropische ontbossing. Het directe verband tussen de commerciële kap van tropisch hardhout en ontbossing is uiterst zwak. Een veel belangrijkere factor is het "omzetten" van bossen in landbouwgrond (ongeveer 80% van alle ontbossing wordt veroorzaakt omdat ruimte voor landbouw, inclusief veehouderij, gemaakt moet worden). Zoals veel bosbouwers en milieubeschermers benadrukken bestaat er echter wel een sterk indirect verband tussen commerciële, selectieve houtkap en oprukkende landbouw. De bosbouwsector zorg namelijk voor het aanleggen van een infrastructuur in gebieden waar (selectief) gekapt is. Dit maakt het bedrijven van landbouw in deze gebieden aantrekkelijker.

    Een veel gehoorde beleidsaanbeveling is dat boeren uit de bossen geweerd moeten worden, bij voorkeur door een algemeen ontwikkelingsbeleid gericht op het tegengaan van te snelle bevolkingsgroei, het bevorderen van alfabetisering en het hervormen van de landbouwsector. Ongetwijfeld wordt hiervoor met de beste bedoelingen gepleit. Dit proefschrift toont echter aan dat dit beleid niet altijd bevorderlijk is voor natuurbehoud.

    In hoofdstuk 3 wordt de relatie tussen de (dreiging van) oprukkende boeren en het kaptempo van bosbouwers onderzocht. Omdat, zoals vermeld, conversie van bossen in landbouwgrond met name voorkomt in selectief gekapt bos, kunnen bosbouwers met kapconcessies voor meerdere jaren de schade door oprukkende landbouwers beïnvloeden door hun kapbeslissingen ("in welk tempo zet ik mijn ongestoorde, primaire bos om in makkelijk toegankelijk, secundair bos?") te veranderen. Het verminderen van schade zal overwogen worden indien het bosbouwers is toegestaan na verloop van tijd terug te keren naar het opengelegde gebied voor aanvullende kap. Met een model waar schade aan het bosbestand van een houtbedrijf positief gerelateerd is aan de omvang van het secundaire bos laten we zien dat de dreiging van oprukkende boeren twee effecten heeft. Aan de ene kant zullen bosbouwers de kap in toegankelijke bossen intensiveren om de brandende boeren vóór te zijn. Een andere reactie is het vertragen van de omzetting van ongestoorde (en ontoegankelijke) primaire bossen in secundaire bossen. We concluderen dat de dreiging van landbouwers leidt tot minder secundair en meer primair bos. Afhankelijk van de maatschappelijke waardering voor deze verschillende bossystemen kan dit uit oogpunt van natuurbehoud een verbetering of een verslechtering inhouden.

    Het huidige tempo van ontbossing is volgens velen te hoog. Een mogelijke verklaring is dat kapbedrijven een te hoge rentevoet hanteren bij het beslissen over de spreiding van kapactiviteiten over de tijd. Immers, veelal wordt verondersteld dat hogere discontovoeten (implicerend dat relatief meer belang wordt gehecht aan huidige consumptie dan aan toekomstige consumptie) ondubbelzinnig negatief uitpakken voor natuurbescherming. Een tweede doelstelling van hoofdstuk 3 is te onderzoeken of dit correct is in de context van een model waarin onderscheid gemaakt wordt tussen primaire en secundaire bossen en waarin een winstmaximaliserend bedrijf geconfronteerd wordt met een overheid die bepaalde eisen stelt. We laten zien dat hoge rentevoeten niet noodzakelijkerwijs versnelde kap uitlokken. Het selectief kappen van primair bos betekent namelijk automatisch dat secundair bos gecreëerd wordt. Bij optimaal bosbeheer wordt de winst door kap in beide typen bos in de afweging betrokken. We laten zien dat hoge discontovoeten de baten van het omzetten van primair bos in secundair bos verlagen. Daarmee wordt het tempo vertraagd waarin deze primaire bossen dienen te worden gekapt om de winst te maximaliseren.

    In hoofdstuk 4 onderzoeken we of het verschaffen van ontwikkelingsgeld aan ontwikkelingslanden een efficiënt instrument is om tropische ontbossing af te remmen. Op basis van een model waar de overheid van een Derde Wereldland de baten van bosbeheer maximaliseert, in dit geval opbrengsten uit verkoopbaar hout en niet-gebruikswaarden gekoppeld aan bosbescherming, is in het verleden geconcludeerd dat ontwikkelingshulp leidt tot extra bosbescherming. De redenering luidt als volgt: extra geld door middel van internationale transfers leidt tot meer consumptie in het Derde Wereldland, zodat de marginale baten van consumptie zullen dalen. Om het evenwicht te herstellen moeten de marginale baten van bosbescherming ook dalen, hetgeen alleen bereikt kan worden door het bosareaal uit te breiden. We hebben dit model uitgebreid en realistischer gemaakt door een risico-mijdende overheid en onzekerheid met betrekking tot toekomstige houtprijzen te veronderstellen. Uiteraard leidt deze uitbreiding normaliter tot afremmen van de kapinspanning. In aanvulling op dit effect hebben internationale donaties in het uitgebreide model een tweede effect: de overheid wordt door het extra geld minder risico-mijdend en laat zich in mindere mate door de onzekere prijzen afremmen om bos te kappen. De conclusie is dat de effectiviteit van internationale transfers als instrument om bij te dragen tot bosbescherming in het verleden is overschat.

    In hoofdstuk 5 en 6 behandelen we enkele economische achtergronden van het beschermen van bepaalde diersoorten. In hoofdstuk 5 staat het verbod op de handel in ivoor centraal. Met de bedoeling om olifanten te beschermen is hiertoe, na enkele decennia van grootschalige olifantenslacht, besloten aan het einde van de jaren '80. Tot op heden heeft dit beleid bijgedragen aan herstel van olifantenpopulaties. Met een eenvoudig economisch model hebben we onderzocht of een handelsverbod altijd dit effect zal blijven hebben. Dit is waarschijnlijk niet het geval. Voor een overheid levert het beheren van een populatie levende olifanten verschillende baten op: het trekt toeristen aan en, na eventuele opheffing van het verbod, zijn olifanten een bron van ivoor en andere nuttige producten. Aan de andere kant leveren olifanten schade op aan landbouwgewassen en mogelijkerwijs ook aan natuurparken. Zolang het handelsverbod gehandhaafd blijft zal een overheid proberen de baten van de bescherming van een extra olifant (in dit geval dus inkomsten uit toerisme) gelijk te stellen aan de kosten die deze olifant met zich meebrengt. Dit wordt bereikt door regelmatig olifantenpopulaties uit te dunnen, ook al mag het aldus verkregen ivoor niet verkocht worden. Dergelijke operaties zijn in enkele landen al aan de gang. Indien het handelsverbod wordt opgeheven zal de overheid olifanten ook beschouwen als een vernieuwbare bron van ivoor. Het bejagen van olifanten voor ivoor levert dan directe baten op en het laten leven van een olifant wordt een soort van investering. Met behulp van data voor Afrika in het algemeen en Kenia in het bijzonder laten we zien dat de optimale populatie olifanten zoals die met een handelsverbod door een overheid wordt nagestreefd niet noodzakelijkerwijs groter is dan de optimale populatie met handel in ivoor. Een belangrijke factor die de optimale hoeveelheid olifanten in de situatie met handel bepaald is de hoogte van de discontovoet die de overheid gebruikt. Een hoge discontovoet leidt tot lage olifantenpopulaties wanneer handel in ivoor is toegestaan, en omgekeerd. De discontovoet waarbij de hoeveelheid olifanten met handel in ivoor de optimale populatie met een handelsverbod overtreft is in de nabijheid van de "sociale discontovoet". Als de discontovoet zoals gehanteerd door Afrikaanse overheden lager wordt dan deze break even discount rate, dan zijn olifanten gebaat bij handel in ivoor. Aangezien de discontovoet waarschijnlijk niet constant is (veelal wordt verondersteld dat de discontovoet een afnemende functie van het inkomen is), concluderen we dat olifantenbeschermers in de toekomst wellicht zullen moeten pleiten voor opheffing van het handelsverbod. In het model hebben we geen rekening gehouden met stroperij. Dit beschouwen we een van de noodzakelijke uitbreidingen voor de toekomst.

    In hoofdstuk 6 bekijken we de economische achtergrond van het verbod op de commerciële walvisvaart. We berekenen de optimale hoeveelheid dwergvinvissen in het Noordoostelijk deel van de Atlantische oceaan met behulp van een model waarin we rekening houden met de niet-gebruikswaarden van levende walvissen (de populariteit van organisaties als Greenpeace geeft aan dat veel mensen "nut" ontlenen aan levende walvissen). In tegenstelling tot ander onderzoek concluderen we dat de huidige populatie dwergvinvissen te laag is. Bovendien blijkt dat het optimaal is om volledig van walvisvangst af te zien tot de populatie gegroeid is tot de optimale omvang. Het moratorium is dus economisch te verdedigen. In het hoofdstuk demonstreren we tot slot dat een simpel statisch model, dat door sommige onderzoekers wordt gebruikt om dit soort problematiek te benaderen, ongeschikt is. Het model leidt tot beleidsaanbevelingen die diametraal tegenover de beleidsimplicaties van een dynamische specificatie staan.

    De hoofdstukken 7, 8 en 9 betreffen visserijeconomie. Zoals besproken in hoofdstuk 2 heeft exploitatie van de zee gedurende een lange tijd plaatsgevonden onder condities van open access. Dit betekent dat het niet mogelijk was om geïnteresseerde vissers te weren van bepaalde visgronden. Omdat niemand geweerd kon worden, voelde niemand zich verantwoordelijk voor een duurzaam beheer. Iedereen zal proberen op zo kort mogelijk termijn zo veel mogelijk geld te verdienen door vis te vangen voordat een andere visser daar aan toe komt. Onder open access verdwijnt de rent volledig: er wordt zoveel gevist dat de prijs uiteindelijk gelijk is aan de marginale vangstkosten. Aan het eind van de jaren '70 is aan deze toestand een einde gekomen door het instellen van exclusieve zones waarbinnen overheden het recht krijgen om buitenstaanders te weren en eigen beleid te voeren. We hebben in hoofdstuk 7 onderzocht of de overgang van open access naar een situatie waar overheidsbeleid gevoerd kan worden heeft geleid tot een beter beheer van visbestanden. Op basis van de economische theorie kan voorspeld worden dat overheden (net als bedrijven met gegarandeerde eigendomsrechten) rekening houden met levende vissen als investering. Dit betekent dat de rent van de hulpbron positief moet worden. Empirisch onderzoek met behulp van Duitse data wijst uit dat de rent inderdaad positief geworden is na instellen van Europees visserijbeleid.

    De conclusie uit hoofdstuk 7 is zeker niet dat het huidige beleid optimaal is. Er werd slechts geconcludeerd dat vergeleken met vroeger de hulpbron nu efficiënter geëxploiteerd wordt. Ander onderzoek heeft aangetoond dat het huidige beleid verre van optimaal is. Een verklaring voor suboptimaal visserijbeheer (die verrassend vaak over het hoofd wordt gezien) is dat de standaard-veronderstelling dat overheden proberen "de welvaart voor de samenleving te maximaliseren", niet opgaat. De overheid wordt beïnvloedt door belangengroepen met bepaalde doelstellingen, die kunnen afwijken van wat sociaal wenselijk is. In hoofdstuk 8 laten we zien dat een belangengroepen- benadering, waarin we vissers, arbeiders en consumenten onderscheiden, leidt tot beheer dat afwijkt van hetgeen standaardmodellen voorschrijven. De observatie dat er onvoldoende vis rondzwemt in de Noordzee hoeft niet noodzakelijkerwijs te impliceren dat de overheid haar doelstellingen niet haalt door het verkeerd inzetten van bepaalde instrumenten. Het kan even goed wijzen op afwijkende doelstellingen als gevolg van lobbyende belangengroepen.

    In hoofdstuk 8 wordt expliciet rekening gehouden met de "macht" van de visserijsector. Het is niet realistisch om te veronderstellen dat een overheid simpelweg een bepaald beleid kan voeren dat rechtstreeks tegen de belangen van bepaalde groepen ingaat. In hoofdstuk 9 laten we zien hoe, in het geval van de visserij, een overheid beperkende maatregelen (zoals het verkleinen van quota) kan doorvoeren zonder de belangen van de vissers al te zeer te schaden. Het instellen van een termijnmarkt voor verhandelbare visquota neemt het prijsrisico dat vissers lopen voor deze quota weg. Dit betekent dat een risico-mijdende visser beter af is dan voorheen. Dit biedt het perspectief om op hetzelfde moment het quotum te verlagen, zodat per saldo de visser niet beter of slechter af is. Financiële instrumenten kunnen dus (in theorie) leiden tot bescherming van natuurlijke hulpbronnen.

    Het proefschrift bevat tot slot twee hoofdstukken over bosbouw waarin onzekerheid een belangrijke rol speelt. In hoofdstuk 10 laten we zien hoe een bepaald soort onzekerheid met betrekking tot de (veelal strijdige) voorkeuren van beleidmakers (bijvoorbeeld: "werkgelegenheid is heel belangrijk, maar de hoeveelheid natuur mag niet veel kleiner worden") geïncorporeerd kan worden in een landgebruiksmodel. Daarnaast behandelen we onzekerheid die samenhangt met gebrekkige kennis omtrent technische coëfficiënten in bosbouwmodellen. We gebruiken fuzzy set theorie, gebaseerd op membership functions, om onzekerheid te modelleren. Een cruciaal aspect van fuzzy logic is dat elementen gedeeltelijk tot een bepaalde set kunnen behoren. We vinden dat de resulterende landallocatie te verkiezen valt boven de uitkomsten van een rechttoe-recht-aan model.

    In hoofdstuk 11 behandelen we een heel ander soort onzekerheid. Zoals boven vermeld fluctueren houtprijzen in de praktijk. In tegenstelling tot .fuzzy set theorie (waarbij niet het plaatsvinden van een gebeurtenis onzeker is, maar de gebeurtenis zelf) is de kansverdeling van de stochastische prijs bekend. In de literatuur is een zoekmodel met reserveringsprijzen ontwikkeld om de baten van een strategisch, flexibel kapbeleid (kappen wanneer de prijs hoger is dan de reserveringsprijs, afzien van kappen indien de prijs lager is) te kunnen vergelijken met de opbrengsten van het meer rigide Faustmann model (zie ook hoofdstuk 2). Uit studies blijkt dat de winsten van Boseigenaren met ongeveer 30% stijgen wanneer een reserveringsprijs-benadering gekozen wordt. In hoofdstuk 11 hebben we dit model uitgebreid door in aanvulling op strategische eindkap ook strategisch uitdunnen in ogenschouw te nemen. We vinden dat de reserveringsprijs voor uitdunnen altijd lager is dan de reserveringsprijs voor kappen en dat een strategisch kapbeleid ten aanzien van uitdunnen de winst van een boseigenaar substantieel verhoogd. De extra baten van flexibel uitdunnen zijn, in overeenstemming met de verwachtingen, minder groot dan de extra baten van het volgen van een strategisch eindkapbeleid.

    Inzet van een tendersysteem bij de SBL-regeling
    Ham, A. van den; Kolkman, G. - \ 1996
    Wageningen : IBN-DLO - 45
    bosbouw - weiden - bossen - landbouwgrond - relaties - ontbossing - bebossing - subsidies - premies - regering - bedrijfsvoering - bestedingen - dienstensector - overheidsbestedingen - nederland - voorzieningen - forestry - pastures - forests - agricultural land - relationships - deforestation - afforestation - subsidies - grants - government - management - expenditure - services - public expenditure - netherlands - facilities
    Particuliere bosbouw in Nederland: een nieuwe toekomst?
    Wiersum, K.F. - \ 1996
    Nederlands Bosbouwtijdschrift 68 (1996)1. - ISSN 0028-2057 - p. 12 - 17.
    bosbouw - bosbezit - particuliere bosbouw - bossen - particulier eigendom - weiden - landbouwgrond - relaties - ontbossing - bebossing - inkomen - rendement - bestedingen - winsten - kosten - bosbedrijfsvoering - investering - financiën - nederland - forestry - forest ownership - private forestry - forests - private ownership - pastures - agricultural land - relationships - deforestation - afforestation - income - returns - expenditure - profits - costs - forest management - investment - finance - netherlands
    The effects of changing land use on the behavior of copper in the soil
    Koopmans, G.F. - \ 1995
    Haren (Gr.) : AB-DLO (Rapport / DLO - Instituut voor Agrobiologisch en Bodemvruchtbaarheidsonderzoek 30) - 24
    koper - bodem - bosbouw - weiden - bossen - landbouwgrond - relaties - ontbossing - bebossing - copper - soil - forestry - pastures - forests - agricultural land - relationships - deforestation - afforestation
    Nederlandse ervaringen met de biomassaproduktie van populier en wilg in zeer korte omlopen
    Burg, J. van den; Dik, E.J. - \ 1995
    Nederlands Bosbouwtijdschrift 67 (1995)1. - ISSN 0028-2057 - p. 23 - 27.
    bosbouw - bosplantages - intensieve houtteelt - biomassa - snelgroeiende stammen - weiden - bossen - landbouwgrond - relaties - ontbossing - bebossing - nederland - forestry - forest plantations - intensive silviculture - biomass - rapidly growing strains - pastures - forests - agricultural land - relationships - deforestation - afforestation - netherlands
    La regeneration de l'espace sylvo-pastoral au Sahel : une etude de l'effet de mesures de conservation des eaux et des sols au Burkina Faso
    Hien, F.G. - \ 1995
    Agricultural University. Promotor(en): L. Stroosnijder. - S.l. : Hien - 223
    bosbouw - weiden - bossen - landbouwgrond - relaties - ontbossing - bebossing - silvopastorale systemen - bosweiden - erosiebestrijding - waterbescherming - bodembescherming - duurzaamheid (sustainability) - natuurlijke hulpbronnen - hulpbronnengebruik - bescherming - herstel - burkina faso - forestry - pastures - forests - agricultural land - relationships - deforestation - afforestation - silvopastoral systems - woodland grasslands - erosion control - water conservation - soil conservation - sustainability - natural resources - resource utilization - protection - rehabilitation - burkina faso
    Sahelian rangelands are subject to degradation caused by physical and human factors. This report presents the results of recent research in Burkina Faso on methods for regenerating such rangelands. It begins with an overview of existing regeneration methods. Quantitative ecological field work conducted at two representative sites to understand the regeneration processes, to determine the sustainability of these processes and to understand reasons for success or failure of regeneration technology is described. Water and nutrient (N,P and K) balances as well as vegetation dynamics were studied for different soil and water conservation technologies. A major conclusion is that degraded and crusted soils can only be regenerated by modifying the water balance. Under improved infiltration, subsequent biological processes appear to be able to transform degraded soils into productive soils. However, an improved availability of water often triggers an immediate shortage of nitrogen. Deep infiltration of water stimulates the growth of trees and shrubs which have a stabilizing effect on the overall regeneration process of Sahelian rangelands.
    Le système d'élevage Peulh dans le sud du Burkina Faso. Une étude agro-écologique du département de Tô (Province de la Sissili).
    Boer, W.F. de; Kessler, J.J. - \ 1994
    Unknown Publisher (Documents sur la Gestion des Ressources Tropicales 4) - 106
    bosbouw - weiden - bossen - landbouwgrond - relaties - ontbossing - bebossing - silvopastorale systemen - bosweiden - bedrijfssystemen - zoötechniek - burkina faso - agro-ecologie - forestry - pastures - forests - agricultural land - relationships - deforestation - afforestation - silvopastoral systems - woodland grasslands - farming systems - zootechny - burkina faso - agroecology
    Organic carbon turnover in three tropical soils under pasture after deforestation.
    Veldkamp, E. - \ 1994
    Soil Science Society of America Journal 58 (1994). - ISSN 0361-5995 - p. 175 - 180.
    bodem - koolstof-stikstofverhouding - kooldioxide - bosbouw - woeste grond - landgebruik - bossen - relaties - ontbossing - bebossing - costa rica - soil - carbon-nitrogen ratio - carbon dioxide - forestry - waste land - land use - forests - relationships - deforestation - afforestation - costa rica
    Perspectives pour le développement soutenu des systèmes de production agrosylvopastorale au Sanmatenga, Burkina Faso.
    Hoek, R. van der; Groot, A. ; Hottinga, F. ; Kessler, J.J. ; Peters, H. - \ 1993
    Wageningen : Unknown Publisher (Documents sur la Gestion des Ressources Tropicales 3) - 73
    bosbouw - weiden - bossen - landbouwgrond - relaties - ontbossing - bebossing - silvopastorale systemen - bosweiden - plattelandsplanning - plattelandsontwikkeling - sociale economie - burkina faso - economische planning - forestry - pastures - forests - agricultural land - relationships - deforestation - afforestation - silvopastoral systems - woodland grasslands - rural planning - rural development - socioeconomics - burkina faso - economic planning
    Soil organic carbon dynamics in pastures established after deforestation in the humid tropics of Costa Rica
    Veldkamp, E. - \ 1993
    Agricultural University. Promotor(en): N. van Breemen. - S.l. : Veldkamp - ISBN 9789054851691 - 117
    plantensuccessie - ontbossing - organische verbindingen - bodem - bodemchemie - graslanden - biocenose - ecosystemen - kringlopen - biogeochemie - bosbouw - woeste grond - landgebruik - bossen - relaties - bebossing - costa rica - lucht - hygiëne - luchtverontreiniging - kooldioxide - plant succession - deforestation - organic compounds - soil - soil chemistry - grasslands - biocoenosis - ecosystems - cycling - biogeochemistry - forestry - waste land - land use - forests - relationships - afforestation - costa rica - air - hygiene - air pollution - carbon dioxide

    Currently, rates of deforestation in the tropics are probably higher than ever before in the past. As a consequence, changes in the earth's physical and chemical environments are proceeding at unprecedented rates. Increasing atmospheric concentrations of CO 2 , N 2 O and other trace gases, caused by enhanced emissions from soils after forest clearing, show that deforestation in tropical areas is of global importance. Recent estimates suggest a net release of carbon from the world's tropics, due to deforestation, of between 0.42 and 1.60 Pg C yr -1(1 Pg = 10 15g) of which 0.1 to 0.3 Pg C yr -1are attributed to decreases in soil organic matter content. This carbon release from tropical areas is second only to the global release from the burning of fossil fuels (which is about 5.3 Pg C yr -1).

    The main objective of this thesis was to quantify the changes in soil organic carbon storage and the resulting release of CO 2 after the conversion of tropical rain forest to pasture on two contrasting soil types in the humid tropics of Costa Rica. To study changes in soil organic carbon storage, sites of an Andisol and an Inceptisol, cleared at different times in the past (deforestation sequences) were compared. A deforestation map, based on aerial photographs from the period 1952 - 1984, was made for a part of the Atlantic Zone of Costa Rica, providing a well documented history of forest clearing. Using GIS techniques, this deforestation map was combined with an available soil map to select the study sites. Analysis of deforestation patterns on the map demonstrated a close relation of deforestation rate with accessibility and soil quality.

    Soil organic matter levels are the result of complex production and decomposition processes. The input of carbon from grass plant roots into the soil was quantified, using pulse labelling with 14C. The pulse labelling experiment revealed that root dry matter production of an improved pasture like Brachiaria (12 Mg ha -1yr -1) was about twice the root production of a low-productive species like Axonopus (6 Mg ha-1 yr-1). Root biomass of Brachiaria was about three times the root biomass of Axonopus due to higher residence time of carbon in the root biomass of Brachiaria as compared to Axonopus . Root exudates of grass plants were found to have a minor direct contribution to the longer term carbon dynamics, either because exudation rate was small or because decomposition was fast and complete.
    Decomposition of soil organic matter was measured using the δ 13C method, which uses differences in natural 13C isotope levels in vegetation (C3 and C4 vegetation) and soil organic matter to calculate changes in soil organic carbon. The method is applicable in soil organic matter studies where a change from C3 to C4 vegetation has occurred (or vice versa). It was demonstrated that for a correct application of the method, detailed information of changes in bulk densities accompanying changes in land use was vital. An uncertainty analysis of the δ 13C method demonstrated that the output of the δ 13C method in soil organic matter studies was highly variable due to variations in the input data. Spatial variability was the main source of the uncertainty in input data. However, variations due to sampling error and short scale variability were considerable and should not be ignored.

    Information on carbon input and decomposition was integrated, using a simple structured soil organic carbon (SOC) model which included carbon isotope fractionation during decomposition and depth dependent decomposition and humification rates. With this model, the observed changes in soil organic carbon and corresponding δ 13C levels during the conversion from a humid tropical forest to a cattle pasture were simulated successfully for the two soil types. With the calibrated model the cumulative net C02 release was calculated. The cumulative net release of CO 2 for pastures with low productive grass species (Axonopus compressus), varied from 31.5 (Humitropept) to 60.5 Mg C ha -1(Hapludand) in the first 20 years after forest clearing. These cumulative emissions could be reduced to 12.0 and 24.7 Mg C ha -1respectively, if higher productive grass species (e.g. Brachiaria dictyoneura ) would be introduced into the area.

    Decomposition rates were strongly influenced by depth. Inclusion of deeper layers in soil organic carbon simulation studies and considering carbon isotopes will probably improve the performance of SOC models in long-term studies.

    Effect of pasture age on soil trace-gas emissions from a deforested area of Costa Rica.
    Keller, M. ; Veldkamp, E. ; Weitz, A.M. ; Reiners, W.A. - \ 1993
    Nature 365 (1993). - ISSN 0028-0836 - p. 244 - 246.
    graslanden - lucht - hygiëne - luchtverontreiniging - stikstofoxiden - bosbouw - woeste grond - landgebruik - bossen - relaties - ontbossing - bebossing - broeikaseffect - opwarming van de aarde - costa rica - grasslands - air - hygiene - air pollution - nitrogen oxides - forestry - waste land - land use - forests - relationships - deforestation - afforestation - greenhouse effect - global warming - costa rica
    Samengaan van land- en bosbouw in bedrijfsverband
    Rijk, P.J. - \ 1992
    Den Haag : LEI-DLO (Mededeling / Landbouw-Economisch Instituut 468) - ISBN 9789052421735 - 59
    bosbouw - landbouw - relaties - weiden - bossen - landbouwgrond - ontbossing - bebossing - nederland - forestry - agriculture - relationships - pastures - forests - agricultural land - deforestation - afforestation - netherlands
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