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This thesis investigates the impact of domestic transport costs and location on exports originating from exporting regions within a developing country. It is presented in the form of three articles, each addressing a different aspect. These articles are accompanied by a literature review of the background and impact of domestic transport costs on trade. The first article provides empirical evidence for the significance of domestic transport costs in exports and the spatial location of manufacturing exporters. Cubic-spline density functions are used and the results indicate (a) the proximity to a port is an important consideration in most export-oriented manufacturing firms' location, with more than 70% of manufactured exports in South Africa originating from a band of 100 km from an export hub; and (b) there appears to be a second band of these firms at a distance of between 200 and 400 km from the hub. Between 1996 and 2004, manufactured exports in the band between 200 km and 400 km from the nearest hub increased, suggesting either an increase in manufactured exports that depend on natural resources due to demand factors, and/or a decrease in domestic transport costs, amongst others. The second article investigates the question of the location of exporters of manufactured goods within a country. Based on insights from new trade theory, the new economic geography (NEG) and gravity-equation modelling, an empirical model is specified with agglomeration and increasing returns (the home-market effect) and transport costs (proxied by distance) as major determinants of the location decision of exporters. Data from 354 magisterial districts in South Africa are used with a variety of estimators (OLS, Tobit, RE-Tobit) and allowances for data shortcomings (bootstrapped standard errors and analytical weights) to identify the determinants of regional manufactured exports. It is found that the home-market effect (measured by the size of local GDP) and distance (measured as the distance in km to the nearest port) are significant determinants of regional manufactured exports. This article contributes to the literature by using developing country data, and by adding to the small literature on this topic. This article complements the work of Nicolini (2003) on the determinants of exports from European regions and finds that the home-market effect is relatively more important in the developing country context (South Africa), a finding consistent with theoretical NEG models such as those of Puga (1998). The third article is an empirical study of the relationship between export diversity and economic growth in a developing country context. Using export data from19 sectors within 354 sub-national (magisterial) districts of South -Africa, various measures of subnational export diversity are constructed. It is found that it is not only important how much is exported, but that it is also important what it is that is exported. Regions with less specialisation and more diversified exports generally experienced higher economic growth rates, and contributed more to overall exports from South Africa. It is also found that distance (and thus domestic transport costs) from a port is inversely related to the degree of export diversity. Estimating a cubic-spline density function for the Herfindahl index measure of export diversity, it is found that export diversity declines as the distance from a port (export hub) increases. Most magisterial districts with high export diversity values are located within 100 km of the nearest port. Furthermore, comparing the cubic-spline density functions for 1004 with those of 1996 shows that distance (domestic transport costs) has become more important since 1996 (under greater openness) with magisterial districts located further than 100 km from the ports being less diverse in 2003 than in 1996. One may speculate that a possible explanation for this changing pattern of export diversity may be the impact of greater foreign direct investment (FDI) in South Africa since 1996. / Thesis (Ph.D. (International Commerce))--North-West University, Potchefstroom Campus, 2007

Thesis (Ph.D. (International Commerce))--North-West University, Potchefstroom Campus, 2007.

This thesis investigates the impact of domestic transport costs and location on exports originating from exporting regions within a developing country. It is presented in the form of three articles, each addressing a different aspect. These articles are accompanied by a literature review of the background and impact of domestic transport costs on trade. The first article provides empirical evidence for the significance of domestic transport costs in exports and the spatial location of manufacturing exporters. Cubic-spline density functions are used and the results indicate (a) the proximity to a port is an important consideration in most export-oriented manufacturing firms' location, with more than 70% of manufactured exports in South Africa originating from a band of 100 km from an export hub; and (b) there appears to be a second band of these firms at a distance of between 200 and 400 km from the hub. Between 1996 and 2004, manufactured exports in the band between 200 km and 400 km from the nearest hub increased, suggesting either an increase in manufactured exports that depend on natural resources due to demand factors, and/or a decrease in domestic transport costs, amongst others. The second article investigates the question of the location of exporters of manufactured goods within a country. Based on insights from new trade theory, the new economic geography (NEG) and gravity-equation modelling, an empirical model is specified with agglomeration and increasing returns (the home-market effect) and transport costs (proxied by distance) as major determinants of the location decision of exporters. Data from 354 magisterial districts in South Africa are used with a variety of estimators (OLS, Tobit, RE-Tobit) and allowances for data shortcomings (bootstrapped standard errors and analytical weights) to identify the determinants of regional manufactured exports. It is found that the home-market effect (measured by the size of local GDP) and distance (measured as the distance in km to the nearest port) are significant determinants of regional manufactured exports. This article contributes to the literature by using developing country data, and by adding to the small literature on this topic. This article complements the work of Nicolini (2003) on the determinants of exports from European regions and finds that the home-market effect is relatively more important in the developing country context (South Africa), a finding consistent with theoretical NEG models such as those of Puga (1998). The third article is an empirical study of the relationship between export diversity and economic growth in a developing country context. Using export data from19 sectors within 354 sub-national (magisterial) districts of South -Africa, various measures of subnational export diversity are constructed. It is found that it is not only important how much is exported, but that it is also important what it is that is exported. Regions with less specialisation and more diversified exports generally experienced higher economic growth rates, and contributed more to overall exports from South Africa. It is also found that distance (and thus domestic transport costs) from a port is inversely related to the degree of export diversity. Estimating a cubic-spline density function for the Herfindahl index measure of export diversity, it is found that export diversity declines as the distance from a port (export hub) increases. Most magisterial districts with high export diversity values are located within 100 km of the nearest port. Furthermore, comparing the cubic-spline density functions for 1004 with those of 1996 shows that distance (domestic transport costs) has become more important since 1996 (under greater openness) with magisterial districts located further than 100 km from the ports being less diverse in 2003 than in 1996. One may speculate that a possible explanation for this changing pattern of export diversity may be the impact of greater foreign direct investment (FDI) in South Africa since 1996. / Thesis (Ph.D. (International Commerce))--North-West University, Potchefstroom Campus, 2007

O objetivo desta dissertação é analisar a viabilidade do transporte marítimo de automóveis novos por cabotagem no Brasil, buscando uma alternativa de transporte, pois atualmente este transporte somente é realizado pelo modal rodoviário. A utilização da cabotagem como transporte de cargas tem aumentado desde a promulgação da Lei de Modernização dos Portos (lei 8.630), em 1993. Nesta mesma época, as fábricas de veículos começaram a passar por um processo de desconcentração geográfica, se deslocando da região Sudeste, e necessitando de transportes mais eficientes. Para observar se tal alternativa é viável economicamente, foi elaborado um estudo de caso e foram usados os dados de uma montadora específica. Esta montadora possui fábricas nos municípios de Camaçari (BA) e de São Bernardo do Campo (SP) e precisa distribuir sua produção em 275 concessionárias espalhadas pelo país. A partir do levantamento e análise dos custos rodoviários e de cabotagem para o transporte de automóveis, foi desenvolvido um modelo de transporte solucionado com o uso de técnicas de programação linear cujas soluções a partir da minimização dos custos de transporte apontaram para o uso ou não da cabotagem. As rotas que apresentaram maiores ganhos econômicos têm como característica uma grande distância entre a fábrica e as concessionárias e uma proximidade dos portos de destino das concessionárias. / This study aims to examine the feasibility of costal shipping of new cars by cabotage in Brazil, searching for an alternative system, since, currently, this transport is performed solely by road transportation. The use of cabotage as cargo transportation has increased since the enactment of the Modernization of Ports Law (Act 8630) in 1993. Since then, automobile makers started to undergo a decentralization process, moving away from the Southeast, and, therefore, requiring more efficient transport. To evaluate the economical feasibility of this alternative, a case study was established and data were collected from a specific auto maker. The auto maker has plants in the cities of Camaçari (BA) and São Bernardo do Campo (SP) and needs to distribute its production to 275 authorized dealers across the country. From the study and analysis regarding road and cabotage costs for car transports, it was developed a transportation model whose solutions using linear programming techniques aim to mitigate transportation costs pointing to the use or not of cabotage. Routes that had greater economic yields are characterized by a large distance between the plant and dealers and proximity to destination ports of dealers.

O objetivo desta dissertação é analisar a viabilidade do transporte marítimo de automóveis novos por cabotagem no Brasil, buscando uma alternativa de transporte, pois atualmente este transporte somente é realizado pelo modal rodoviário. A utilização da cabotagem como transporte de cargas tem aumentado desde a promulgação da Lei de Modernização dos Portos (lei 8.630), em 1993. Nesta mesma época, as fábricas de veículos começaram a passar por um processo de desconcentração geográfica, se deslocando da região Sudeste, e necessitando de transportes mais eficientes. Para observar se tal alternativa é viável economicamente, foi elaborado um estudo de caso e foram usados os dados de uma montadora específica. Esta montadora possui fábricas nos municípios de Camaçari (BA) e de São Bernardo do Campo (SP) e precisa distribuir sua produção em 275 concessionárias espalhadas pelo país. A partir do levantamento e análise dos custos rodoviários e de cabotagem para o transporte de automóveis, foi desenvolvido um modelo de transporte solucionado com o uso de técnicas de programação linear cujas soluções a partir da minimização dos custos de transporte apontaram para o uso ou não da cabotagem. As rotas que apresentaram maiores ganhos econômicos têm como característica uma grande distância entre a fábrica e as concessionárias e uma proximidade dos portos de destino das concessionárias. / This study aims to examine the feasibility of costal shipping of new cars by cabotage in Brazil, searching for an alternative system, since, currently, this transport is performed solely by road transportation. The use of cabotage as cargo transportation has increased since the enactment of the Modernization of Ports Law (Act 8630) in 1993. Since then, automobile makers started to undergo a decentralization process, moving away from the Southeast, and, therefore, requiring more efficient transport. To evaluate the economical feasibility of this alternative, a case study was established and data were collected from a specific auto maker. The auto maker has plants in the cities of Camaçari (BA) and São Bernardo do Campo (SP) and needs to distribute its production to 275 authorized dealers across the country. From the study and analysis regarding road and cabotage costs for car transports, it was developed a transportation model whose solutions using linear programming techniques aim to mitigate transportation costs pointing to the use or not of cabotage. Routes that had greater economic yields are characterized by a large distance between the plant and dealers and proximity to destination ports of dealers.

Die wichtigste Frage der Raumwirtschaftstheorie lautet: Welches sind die Ursachen für die Entstehung, den Bestand und die Wandlungen räumlicher Wirtschaftsstrukturen? Zu den markantesten Strukturen gehören zweifellos Agglomerationen, die nicht auf natürliche Ursachen zurückgeführt werden können. Die Neue Ökonomische Geographie gibt eine Antwort auf die Frage nach den Gründen ihrer Existenz aus einem mikroökonomischen Totalmodell, das unterschiedliche Regionen und Produktionssektoren, heterogene Güter und unterschiedliche Transportkosten berücksichtigt. Das vorliegende Buch verfolgt drei Ziele: Zunächst wird dieses neue Paradigma in einen dogmenhistorischen Zusammenhang mit der traditionellen Raumwirtschaftstheorie und Handelstheorie gestellt. Ferner wird das Basismodell des Ansatzes ausführlich beschrieben und danach kritisch diskutiert. Schließlich werden einige Erweiterungsmöglichkeiten aufgezeigt, die in der Lage sind, einige zuvor genannte Kritikpunkte bezüglich des Grundmodells aufzuheben. / The most important question of regional economics is: What are the reasons for the existence, the growth, and the changes of regional economic structures? Without any doubt, agglomerations which are not based on natural sources belong to the most significant regional structures. The New Economic Geography gives answers - based on a microeconomic total model with different regions and industrial sectors, with heterogeneous goods and different transport costs - to the questions with regard to the reasons of the existence of agglomerations. This book pursues three objectives: First of all, the new paradigm is connected with the historical background of the traditional regional economics and trade theory. Furthermore, the basic model is described in detail and then discussed from a critical point of view. Finally, some possible extensions are introduced, which make it possible to eliminate some criticized elements of the basic model.

The current status of road transportation charging in the Czech Republic has been analyzed in terms of costs, which are caused by various categories of vehicles and incomes, which are generated by existing instruments of charging. Significant imbalance of theese indicators for different types of vehicles has been revealed. The measures proposed in thesis aim to eliminate this imbalance and to provide fair charging system that is based on actual costs caused by vehicle.

Cette thèse s'articule autour de trois essais portant sur des questions internationales en économie des ressources naturelles. Le premier essai examine la production et l'échange des ressources non-renouvelables dans un modèle spatial et souligne le rôle de la superficie des pays et du coût des transports dans la détermination du sens de l'échange. Le deuxième essai considère le tarif d'extraction de la rente de rareté liée aux ressources naturelles non-renouvelables avec le modèle spatial développé dans premier essai. Le cadre spatial (plus général) permet de représenter des pays qui sont à la fois importateurs et producteurs de la ressource, ce qui n'est pas possible dans les modèles traditionnels de commerce international où les pays sont traités comme des points (sans dimension). Le troisième essai aborde la question des droits de propriétés sur les zones maritimes et examine l'allocation d'une population de pêcheurs entre les activités productives et non-productives dans une communauté côtière. Le premier chapitre propose un modèle spatial de commerce international des ressources non-renouvelables. Le cadre spatial considère explicitement la différence de taille géographique (superficie) entre les pays et permet ainsi de tenir compte du fait que les gisements naturels et leurs utilisateurs soient dispersés dans l'espace, même à l'intérieur d'un pays. En utilisant un modèle spatial à la Hotelling, nous examinons l'évolution dans le temps du sens de l'échange entre deux pays (ou régions) qui diffèrent du point de vue de leur technologie de production, de leur superficie et de leur dotation en gisement d'une ressource naturelle non-renouvelable. Le chapitre met en évidence le rôle de la taille géographique dans la détermination du sens de l'échange, à côté des explications traditionnelles que sont l'avantage comparatif et les dotations des facteurs. Notre analyse est fondamentalement différente des autres contributions dans la littérature sur le commerce international des ressources naturelles parce qu'elle souligne l'importance de la taille géographique et du coût de transport par rapport à d'autres facteurs dans la détermination des flux de ressource à l'équilibre. Le coût unitaire de transport joue un rôle capital pour déterminer si la différence de superficie entre les pays influence le sens de l'échange à l'équilibre plus que les autres facteurs. Le chapitre discute aussi du caractère régional des échanges qui a été observé pour certaines ressources telles que le minerai de fer et la bauxite. Le chapitre deux aborde la question de la répartition de la rente de rareté liée aux ressources naturelles non-renouvelables entre les pays producteurs et les pays consommateurs. Cette question a été abordée dans la littérature sous une hypothèse quelque peu restrictive. En effet, dans la plupart des travaux portant sur ce sujet le pays importateur est automatiquement considéré comme dépourvu de gisement et donc non producteur de la ressource. Pourtant la réalité est qu'il existe des ressources pour lesquelles un pays est à la fois producteur et importateur. Le cadre d'analyse de ce second essai est le modèle spatial développé dans le premier essai, qui permet justement qu'un pays puisse être à la fois importateur et producteur de la ressource. Le pays importateur détermine alors simultanément le tarif optimal et le taux d'extraction de son propre stock. Nous montrons que le tarif optimal croît au taux d'intérêt et de ce fait, ne crée aucune distorsion sur le sentier d'extraction de la ressource. Le tarif optimal permet de récupérer toute la rente lorsque le pays exportateur ne consomme pas la ressource. Néanmoins, la possibilité pour le pays exportateur de consommer une partie de son stock limite la capacité du pays importateur à récupérer la rente chez le pays exportateur. La présence de gisements de la ressource dans le pays importateur réduit la rente du pays exportateur et de ce fait renforce la capacité du pays importateur à récupérer la rente chez le pays exportateur. Le tarif initial est une fonction décroissante du stock de ressource dans le pays importateur. Cet essai aborde également la question de la cohérence dynamique du tarif obtenu avec la stratégie en boucle ouverte. Le troisième chapitre examine un problème d'allocation de l'effort entre les activités productives (par exemple la pêche) et les activités non productives (par exemple la piraterie maritime) dans une population de pêcheurs. La répartition de la population entre les activités de pêche et la piraterie est déterminée de façon endogène comme une conséquence du choix d'occupation. Nous établissons l'existence d'une multiplicité d'équilibres et mettons en évidence la possibilité d'une trappe de piraterie, c'est-à-dire un équilibre stable où une partie de la population est engagée dans les actes de piraterie. Le modèle permet d'expliquer l'augmentation significative des attaques de piraterie dans le Golfe d'Aden au cours des dernières années. Le chapitre discute aussi des différents mécanismes pour combattre la piraterie et souligne le rôle crucial des droits de propriété. / This thesis consists of three essays on international issues in natural resource economics. The first essay proposes a spatial model of trade in exhaustible resources and emphasizes the role of geographical size and transport costs in the determination of trade patterns. The second essay considers the rent-extracting tariff in a spatial (more general) framework in which the importing country can be simultaneously a producer and an importer of the resource, a feature which is not possible in the traditional trade model, where countries are assumed dimensionless. The third essay tackles the issue of property rights in maritime zones and examines the allocation of a population of fishermen between productive and unproductive activities in a coastal community. The first chapter proposes a model of trade in exhaustible resources that explicitly accounts for the fact that countries have different geographical sizes while resource sites and their users are spatially distributed, even within a country. Using a spatial model à la Hotelling, we examine the evolution over time of the pattern of trade between two countries (or regions) which differ in terms of their technology, their geographical size, and their endowment of some nonrenewable natural resource. The model emphasizes the importance of geographical size in determining trade patterns besides the traditional explanations of comparative advantage and factor endowments. Indeed, three forces influence the direction of international trade in the presence of transport costs. The analysis fundamentally differs from other contributions in the natural resource literature because it emphasizes the importance of geographical size and of transport cost relative to other factors in the determination of the equilibrium resource flows. The unit cost of transport is shown to play a decisive role in determining whether the international asymmetry in terms of geographical sizes of countries has a greater influence than other factors on the equilibrium pattern of trade. The chapter also discusses the regional character of trade which has been observed for some resources such as iron ore and bauxite. Most findings in the literature on tariff and exhaustible resources have been derived under a serious abstraction. Indeed, virtually all contributions on that issue have assumed that no stocks of the resource are available within the importing country's borders and therefore the importing country is not itself a producer. Reality is in fact quite different: there are many instances of countries that are simultaneously importers and producers of a natural resource. The second chapter makes use of the spatial trade model of chapter one to depart from the usual assumption and allow the importing country to have access to a stock of the resource of its own and to determine simultaneously the optimal tariff and the rate of depletion of its own stock. The optimal tariff is shown to increase at the rate of interest and is therefore nondistortionary. Moreover, the optimal tariff captures all the rent if the exporting country gets no utility from consuming the resource. Allowing the exporting country to consume the resource restricts the ability of the importer to capture all of the foreign rent. The presence of resource deposits in the importing country reduces the available rent to foreign producers and, in essence, reinforces the ability of the importer to capture the foreign rent. In effect, the initial tariff is shown to be a decreasing function of the initial resource stock in the importing country. The essay also discusses the time consistency of the open-loop tariff. The third chapter examines how agents in a coastal community allocate effort between productive (fishing) and unproductive (piracy) activities. The allocation of population between fishing activity and piracy attacks is determined endogenously as a consequence of the occupation choice. We prove the existence of multiple equilibria and emphasize the possibility of a piracy trap, that is a steady state equilibrium where part of the population is engaged in piracy acts. The chapter offers an explanation for the significant increase in piracy attacks in the Gulf of Aden in the recent years. The chapter also discusses different schemes in combating piracy and highlights the crucial role of property rights.

Cette thèse s'articule autour de trois essais portant sur des questions internationales en économie des ressources naturelles. Le premier essai examine la production et l'échange des ressources non-renouvelables dans un modèle spatial et souligne le rôle de la superficie des pays et du coût des transports dans la détermination du sens de l'échange. Le deuxième essai considère le tarif d'extraction de la rente de rareté liée aux ressources naturelles non-renouvelables avec le modèle spatial développé dans premier essai. Le cadre spatial (plus général) permet de représenter des pays qui sont à la fois importateurs et producteurs de la ressource, ce qui n'est pas possible dans les modèles traditionnels de commerce international où les pays sont traités comme des points (sans dimension). Le troisième essai aborde la question des droits de propriétés sur les zones maritimes et examine l'allocation d'une population de pêcheurs entre les activités productives et non-productives dans une communauté côtière. Le premier chapitre propose un modèle spatial de commerce international des ressources non-renouvelables. Le cadre spatial considère explicitement la différence de taille géographique (superficie) entre les pays et permet ainsi de tenir compte du fait que les gisements naturels et leurs utilisateurs soient dispersés dans l'espace, même à l'intérieur d'un pays. En utilisant un modèle spatial à la Hotelling, nous examinons l'évolution dans le temps du sens de l'échange entre deux pays (ou régions) qui diffèrent du point de vue de leur technologie de production, de leur superficie et de leur dotation en gisement d'une ressource naturelle non-renouvelable. Le chapitre met en évidence le rôle de la taille géographique dans la détermination du sens de l'échange, à côté des explications traditionnelles que sont l'avantage comparatif et les dotations des facteurs. Notre analyse est fondamentalement différente des autres contributions dans la littérature sur le commerce international des ressources naturelles parce qu'elle souligne l'importance de la taille géographique et du coût de transport par rapport à d'autres facteurs dans la détermination des flux de ressource à l'équilibre. Le coût unitaire de transport joue un rôle capital pour déterminer si la différence de superficie entre les pays influence le sens de l'échange à l'équilibre plus que les autres facteurs. Le chapitre discute aussi du caractère régional des échanges qui a été observé pour certaines ressources telles que le minerai de fer et la bauxite. Le chapitre deux aborde la question de la répartition de la rente de rareté liée aux ressources naturelles non-renouvelables entre les pays producteurs et les pays consommateurs. Cette question a été abordée dans la littérature sous une hypothèse quelque peu restrictive. En effet, dans la plupart des travaux portant sur ce sujet le pays importateur est automatiquement considéré comme dépourvu de gisement et donc non producteur de la ressource. Pourtant la réalité est qu'il existe des ressources pour lesquelles un pays est à la fois producteur et importateur. Le cadre d'analyse de ce second essai est le modèle spatial développé dans le premier essai, qui permet justement qu'un pays puisse être à la fois importateur et producteur de la ressource. Le pays importateur détermine alors simultanément le tarif optimal et le taux d'extraction de son propre stock. Nous montrons que le tarif optimal croît au taux d'intérêt et de ce fait, ne crée aucune distorsion sur le sentier d'extraction de la ressource. Le tarif optimal permet de récupérer toute la rente lorsque le pays exportateur ne consomme pas la ressource. Néanmoins, la possibilité pour le pays exportateur de consommer une partie de son stock limite la capacité du pays importateur à récupérer la rente chez le pays exportateur. La présence de gisements de la ressource dans le pays importateur réduit la rente du pays exportateur et de ce fait renforce la capacité du pays importateur à récupérer la rente chez le pays exportateur. Le tarif initial est une fonction décroissante du stock de ressource dans le pays importateur. Cet essai aborde également la question de la cohérence dynamique du tarif obtenu avec la stratégie en boucle ouverte. Le troisième chapitre examine un problème d'allocation de l'effort entre les activités productives (par exemple la pêche) et les activités non productives (par exemple la piraterie maritime) dans une population de pêcheurs. La répartition de la population entre les activités de pêche et la piraterie est déterminée de façon endogène comme une conséquence du choix d'occupation. Nous établissons l'existence d'une multiplicité d'équilibres et mettons en évidence la possibilité d'une trappe de piraterie, c'est-à-dire un équilibre stable où une partie de la population est engagée dans les actes de piraterie. Le modèle permet d'expliquer l'augmentation significative des attaques de piraterie dans le Golfe d'Aden au cours des dernières années. Le chapitre discute aussi des différents mécanismes pour combattre la piraterie et souligne le rôle crucial des droits de propriété. / This thesis consists of three essays on international issues in natural resource economics. The first essay proposes a spatial model of trade in exhaustible resources and emphasizes the role of geographical size and transport costs in the determination of trade patterns. The second essay considers the rent-extracting tariff in a spatial (more general) framework in which the importing country can be simultaneously a producer and an importer of the resource, a feature which is not possible in the traditional trade model, where countries are assumed dimensionless. The third essay tackles the issue of property rights in maritime zones and examines the allocation of a population of fishermen between productive and unproductive activities in a coastal community. The first chapter proposes a model of trade in exhaustible resources that explicitly accounts for the fact that countries have different geographical sizes while resource sites and their users are spatially distributed, even within a country. Using a spatial model à la Hotelling, we examine the evolution over time of the pattern of trade between two countries (or regions) which differ in terms of their technology, their geographical size, and their endowment of some nonrenewable natural resource. The model emphasizes the importance of geographical size in determining trade patterns besides the traditional explanations of comparative advantage and factor endowments. Indeed, three forces influence the direction of international trade in the presence of transport costs. The analysis fundamentally differs from other contributions in the natural resource literature because it emphasizes the importance of geographical size and of transport cost relative to other factors in the determination of the equilibrium resource flows. The unit cost of transport is shown to play a decisive role in determining whether the international asymmetry in terms of geographical sizes of countries has a greater influence than other factors on the equilibrium pattern of trade. The chapter also discusses the regional character of trade which has been observed for some resources such as iron ore and bauxite. Most findings in the literature on tariff and exhaustible resources have been derived under a serious abstraction. Indeed, virtually all contributions on that issue have assumed that no stocks of the resource are available within the importing country's borders and therefore the importing country is not itself a producer. Reality is in fact quite different: there are many instances of countries that are simultaneously importers and producers of a natural resource. The second chapter makes use of the spatial trade model of chapter one to depart from the usual assumption and allow the importing country to have access to a stock of the resource of its own and to determine simultaneously the optimal tariff and the rate of depletion of its own stock. The optimal tariff is shown to increase at the rate of interest and is therefore nondistortionary. Moreover, the optimal tariff captures all the rent if the exporting country gets no utility from consuming the resource. Allowing the exporting country to consume the resource restricts the ability of the importer to capture all of the foreign rent. The presence of resource deposits in the importing country reduces the available rent to foreign producers and, in essence, reinforces the ability of the importer to capture the foreign rent. In effect, the initial tariff is shown to be a decreasing function of the initial resource stock in the importing country. The essay also discusses the time consistency of the open-loop tariff. The third chapter examines how agents in a coastal community allocate effort between productive (fishing) and unproductive (piracy) activities. The allocation of population between fishing activity and piracy attacks is determined endogenously as a consequence of the occupation choice. We prove the existence of multiple equilibria and emphasize the possibility of a piracy trap, that is a steady state equilibrium where part of the population is engaged in piracy acts. The chapter offers an explanation for the significant increase in piracy attacks in the Gulf of Aden in the recent years. The chapter also discusses different schemes in combating piracy and highlights the crucial role of property rights.