- Email: [email protected]
The economics of forestry and natural resources
Conference
in the metal exchanges to offset price drops generated by expectations not directly related to the market fundamentals. The last session was opened by CESCO’s representative, Juan Eduardo Herrera who supported Schindler’s position of Chile’s need to become a leader in the industry, proposing several alternatives to make this leadership possible. He said producers and consumers should begin informal talks with the idea of forming a study group such as the existing lead and zinc grouping. The task is also to stabilize prices at reasonable and remunerative levels in the long term, adding that US $0.75 per pound responds to those characteristics. Leadership also requires a major participation of the industry in LME and COMEX, not to replace them, but to act as a voting member within the existing organizations. Herrera sided with Stobart and Crowson, calling for a marketing campaign to promote the use of copper and a technological effort to seek new copper products. His presentation was followed by a paper from Juan Enrique Morales, President of Chile’s Institute of Mining Engineers. Morales noted that the Chilean government lacks a long-term mineral policy and called for the formulation of such a policy, providing a glimpse of its possible contents. He said this policy should be coherent with other sectors of the domestic economy, it should be capable of being applied across the board to small- medium- and large-sized operations, and it should remain stable in
time. As far as a production policy goes, he argued against Schindler and Herrera saying that Chile should not expand capacity, but rather stick to present production levels to avoid further price declines. Carlos Rodriguez, Chief Economist of the National Association (Sonami) agreed with Morales on the need to avoid overshooting capacity. He said when the news arrived in the metals exchange that Chile was increasing production, speculators moved out of copper affecting its price. This last presentation initiated a heated debate over production policies with the intervention of all the speakers. The conference was closed by CESCO’s executive director Jorge Bande, who noted that this was the first time in Chile that a broadly-based group of private and governmental institutions had met to discuss copper development alternatives. Bande said that the seminar had given rise to a heightened awareness within the industry of the need for immediate action in the field of promotion and announced the formation of a task group in Chile to suggest policies to the government concerning Chile’s role in the copper industry. The proceedings of the seminar will be published by CESCO with the support of the Friedrich Ebert Foundation that also helped finance the event. For more information, contact CESCO, Lota 2267, of 204, Santiago, Chile.
Book review
very strong grasp of the quantitative techniques such as calculus of variations, optimal control, econometrics and Markov chain stochastic processes; the second, which is less explicit, is a belief that the complex and sensitive issues of forestry can be best handled by neoclassical models. These assumptions narrow down considerably the readers the book will attract. The intention here is not to criticize the relevance of neoclassical models and quantitative techniques in analysing natural resource issues, but only to mention that when a work is published in volume form, one expects its con-
THE
!==~NOMICS
OF FORESTRY
ANDNATURALRESOURCES Per Olov Johansson Lofclren Basil Blackwell, 305 pp, f29.50
and Karl Gustav
Oxford,
UK,
1985,
There are at least two requirements besides an interest in natural resources itself before a reader can appreciate fully this largely theoretical work from two Swedish forest economists, Johansson and Lofgren. The first is a
RESOURCES
POLICY March
1986
Juan O’Brien CESCO Santiago
reporrslBook
review
tents to appeal to readers beyond the academic researchers who, after all, have access to a range of academic journals incorporating models with their attendant proofs. One of the aims of a book on forestry economics, particulary from the academic profession, should be to bridge the comthe between munication gap academics and the policy makers who have less time and opportunity to be exposed to intellectual scrutiny of the subject. This book will hardly be one that the non-academician will find readable.
Many dimensions A problem of reviewing this book is that it covers many dimensions of forest economics as varied as optimal welfare rules for rotation criteria, forestry, cost-benefit propositions for forestry under unemployment, maximization of expected utility of a risk averse forester and many more. It is deep in some parts, superficial in others, and very demanding. If there was a common thread that guided the reader from one issue to another, the task of absorbing the contents would have been much easier. There is not even a concluding chapter that brings the disparate aspects of the various chapters together. The preface is no substitute as it is only a trailer of what to expect. While the first seven chapters flow in a reasonably cohesive manner, the last six seem to be disparate and lumpy. It appears as if the authors have been over-burdened with their research material, which might have been at home in a book of readings rather than being separated into various sections and chapters under the umbrella of the book’s title. Under these circumstances, the reviewer is forced to pick and choose those issues that he is competent in and feels are important, leaving the verification of the individual models and proofs to those readers who have the knowledge and time to scrutinize the various equations to judge their veracity. It has to be mentioned, however, that the various research pieces show analytical depth and dedication to the subject in their own terms.
79
Book review The first two chapters may be skipped by readers already familiar with non-renewable resource theory as expounded in some depth in a host of publications the most comprehensive being by Dasgupta and Heal.’ It was, however, Hotelling’s 1931 classic article that conceptualized the key issues of exploiting stock resources over time.’ The reason the authors start off with the economic principles of non-renewable resources is that they form the core of the theory of renewable resources. In some sense renewable resource theory is a special case of the theory of non-renewable resources, ie if one looks particularly in terms of an exploitation policy of a resource over time which maximizes the net present value of the income stream from the investment. There are some aspects in renewable resource exploitation which make it different from that of nonrenewable resources. One is growth, ie an addition to the net stock, and the other is age, ie the various vintages of the trees in the biomass. These two are interrelated. In forestry there are two kinds of harvests - thinning, to improve stand growth and cutting which is clear felling of the trees. Johansson and Lofgen ignore species classification as another dimension, which is more relevant to tropical forests than temperate forests, given the symbiotic relationship operating among the various species that affect the growth process, Another is the so-called ‘problem of the commons’ arising from common access to a resource which is usually given special treatment in renewable resource literature, particularly fisheries.” But this is in no way a particular problem of renewable resources. as the authors rightly point out. For instance, it is similar when an oil well is simultaneously exploited by two competing companies of different countries as in the North Sea. The ‘gold rush’ seen in earlier times did depict the ‘commons problem’ of producing a socially inefficient exploitation path. The complex dynamism of the forest resource over time together with its multiple uses both as a commercial activity as well as an integrated element of the ecosystem
80
makes the subject quite tricky for analysis. Given this somewhat ski generis character of forestry, are the neoclassical models that the book uses as its framework for analysis adequate to capture the salient factors for policy making? A review of the contents will show that the analysis has been only partial.
Forest rotation Chapters 3 to 8, which form the bulk of the study. delve into the problem of forest rotation, ie choosing an age at which trees ought to be thinned or harvested to maximize the present discounted value of profits. The authors start off with evaluation of an even aged forest under competitive conditions, developing the well known Faustmann formula (later refined by Pressler and Ohlin) that a forest stand shall be harvested when the rate of change of its value with respect to time is equal to the interest on the value of the stand plus interest on the value of the forest land. They investigate how the rotation period is affected by change in prices, wages and interest rates. The authors compare the Faustmann-Pressler-Ohlin formula with other harvesting criteria such as maximum sustained yield and allowable cut. The conclusions are not dissimilar to what has already been written.4 The authors do not, however, attack the maximum sustained yield concept (which is a favourite of some foresters) which is shown to be optimal at least from the assumptions adopted only if the interest rate is zero. This concept ignores all considerations of costs and prices. The issue is whether society can ever have a social time preference rate of interest that is zero, and if so is there any case for maximum sustained yield as a viable strategy in the context of a multi-aged, multi-species forest stand? If the interest rate is an important element, what interest rate is optimal for forestry? These practical issues with which policy makers and foresters grapple, sadly, are not discussed in any depth. Major policy debate on forest investment has been on the kind of discount rate that is
applied to cash flows in forestry - the market rate of interest that is applicable to other competing investments or the social time preference rate of interest which is lower. Another question is whether conservationists would be happier with sustained yield than with the Faustmann-Pressler-Ohlin formula of forest management if they have to make a choice? Chapters 5 and 6 consider the effects of different kinds of taxes on the rotation period and value of forest lands as well as changes in biotechnology. Other extensions include multiage trees, variable timber prices and varying rates of return. The conclusions are intuitively plausible and on the whole non-controversial if one accepts the assumptions of the model. Non-linearities of the specifications by and large, the authors find, do not disturb their results, although it is not clear if this would be the case if the market structure was not one of perfect competition. In Chapter 7 the authors analyse the behaviour of a self-employed farmer and the allocation of time between working in forestry, agriculture and industry, and the effect of taxes on leisure time. There are no surprises in the conclusions. The same can be said for the analysis of the forest industry as a forest owner. If the aim of the latter was to provide a demand function for round wood, one wonders whether there was not a simpler way.
Hotchpotch Chapter 8 is a hotchpotch of analyses that handle too many issues with tenuous links. They start off with defining the equilibrium conditions of a partial equilibrium aggregate supply and demand model; and jump to a section entitled ‘General equilibrium: few comments’ where they mention the possibility of integrating firms and consumers in an Arrow - Debreu type of model; this is followed by an analysis of a monopsonistic competitive market. This subject-hopping shows the jerkiness of the presentation. In subsequent chapters too the various research pieces ‘A bargaining approach to pricing of wood in Sweden’, ‘An
RESOURCES
POLICY March 1986
Book review/Conferences
econometric analysis of aggregate demand for and supply of wood in ‘Welfare theory and the Sweden’, optimal pricing of natural resources’, ‘Cost benefit rules for natural resources’, and ‘The properties of timber supply’, can stand individually on their own and, as mentioned earlier, might have stood out better as a collection of articles in a book of readings rather than in the present form. Cohesiveness of the book is as important as the cogency of the individual parts. Of these various pieces of research, the most interesting from the forest policy point of view is that of applying cost-benefit analysis to natural resources (Chapter 11). There are several complications, the authors conclude. The first which was mentioned in Chapter 3, but unfortunately was not developed further is ‘irreversibility in combination with uncertainty’. This forms the crux of the arguments of those who do not favour the rapid exploitation of tropical species, for their destruction could preclude all the potential benefits arising from future advances in biotechnology. The second is the multiple use of forest lands combining both commercial and non-commercial uses, with the latter non-marketed. This makes it difficult to apply the various conditions developed for optimal rotation and Pareto welfare optimality. The authors discuss whether ‘taking’, ie compensation by the gainers to the losers as a policy rule can lead to a Pareto superior situation, and conclude rightly that the economic criteria which they have developed may not handle these aspects. Choice must often be made on non-economic grounds. Unfortunately, noneconomic factors which are integral to the issues facing forestry today are not treated in any depth. It has to be stressed that economic factors cannot operate in a vacuum. The social, political and institutional environment is important. Another complication that has been picked up by the authors is unemployment although this is not only relevant to natural resources but to other sectors too. They consider whether the optimal rotation period can be relaxed
RESOURCES
POLICY March
1986
in the context of unemployment, and to the controversial conclusion that ‘unemployment (temporary or persistent) is not a sufficient condition to justify marginal departures from the Faustmann solution to the forest management problem’. This may be true if one applies strict financial criteria, using the assumptions of the model. If externalities and noneconomic factors are taken into account, can we expect conditions for achieving a Faustmann solution to be optimal? The costs of higher social security, increased policing and health care resulting from unemployment may outweigh any gains arising from the Faustmann optimal rotation solution. It has to be stressed also that an optimal harvest policy cannot effectively operate out of context of the social, political and institutional environment. one is tempted to ask Finally. whether this book poses and attempts come
to give answers to the key issues facing forestry today, ie the low level of replenishment of tropical forests, acid rain and other forms of pollution, non-wood substitution, the large resources required for sillicultural research and the need for a commodity agreement for wood to ensure longterm supplies? Unfortunately, it does not. Raj Kumar Commonwealth
Secretariat London
‘P. Dasgupta and G.M. Heal, Economic Theory and Exhausti6le Resources, James NisbeKambridge University Press, Oxford, 1979. *H. Hotelling, ‘The economics of exhaustible resourc&‘, Journal of Polifical Economy, Vol 39, 1931, pp 137-l 75. ‘C.W. Clark, Mathematical Bioeconomics: The Ootimal Manaaemenf of Renewable Resoukces, John Wiley, New York, NY, 1976. 4P.A. Samuelson, ‘Economics of forestry in an evolving society’, Economic Inquiry, Vol 14, 1976, pp 466-492.
Conferences of events is compiled from information provided by the respective organizers and from secondary sources. RESOURCES POLICY welcomes information on all conferences revelant to resources issues for listing in this section. The copy deadline is three months before publication. An asterisk denotes a new entry. This calendar
*12-14 March 1986, Boston, MA, USA Conference on THE ECONOMICS OF PRECIOUS METALS MANAGEMENT. Contact International Precious Metals Institute, Government Building. ABE Airport, Allentown. PA 18103, USA. “17-19 March 1986, Washington, DC, USA Energy Technology Conference and Exposition (ET’%). Details from Government Institutes. Inc, PO Box 1096, Rockville, MD 20850, USA. 17-20 March 1986, Jackson, Ml, USA 19% National Meeting of the AMERICAN SURFACE MINING AND RECLAMATION. Call for papers. Details from Dr Robert Knight. Range Science Department, Texas A-and M University. College Station, TX 77843, USA. 24 March4 April 1986, Falmouth, UK NATO Advanced Study Institute meeting on MINERAL PROCESSING AT THE CROSSROADS. Details from Dr B.A. Wills, AS1 Director, Cambourne School of
Mines, Pool, 3SE. UK.
Redruth,
Cornwall
TRlS
‘14 April 1986, Monte Carlo 7th Industrial Minerals International Congress. Please note this conference was originally scheduled to take place in Athens. Contact Diana Little, Deputy Product Sales Manager, Metal Bulletin Conferences Ltd, Pa;k House, Park Terrace, Worcester Park KT4 7HY, UK. *22-23 April 1986, Washington, DC, USA ENVIRONMENTAL LAWS AND REGULATIONS: INTRODUCTORY COURSE. Details from Government Institutes. Inc. PO Box 1096, Rockville, MD 20850, USA. 22-26 April 1986, Jakarta, Indonesia MINING INDONESIA. The second international mining and minerals recovery exhibition. Details from M. Ravner. Exhibition Manager, Overseas Exhibition Services Ltd, I1 Manchester Square, London WlM SAB.
81
in the metal exchanges to offset price drops generated by expectations not directly related to the market fundamentals. The last session was opened by CESCO’s representative, Juan Eduardo Herrera who supported Schindler’s position of Chile’s need to become a leader in the industry, proposing several alternatives to make this leadership possible. He said producers and consumers should begin informal talks with the idea of forming a study group such as the existing lead and zinc grouping. The task is also to stabilize prices at reasonable and remunerative levels in the long term, adding that US $0.75 per pound responds to those characteristics. Leadership also requires a major participation of the industry in LME and COMEX, not to replace them, but to act as a voting member within the existing organizations. Herrera sided with Stobart and Crowson, calling for a marketing campaign to promote the use of copper and a technological effort to seek new copper products. His presentation was followed by a paper from Juan Enrique Morales, President of Chile’s Institute of Mining Engineers. Morales noted that the Chilean government lacks a long-term mineral policy and called for the formulation of such a policy, providing a glimpse of its possible contents. He said this policy should be coherent with other sectors of the domestic economy, it should be capable of being applied across the board to small- medium- and large-sized operations, and it should remain stable in
time. As far as a production policy goes, he argued against Schindler and Herrera saying that Chile should not expand capacity, but rather stick to present production levels to avoid further price declines. Carlos Rodriguez, Chief Economist of the National Association (Sonami) agreed with Morales on the need to avoid overshooting capacity. He said when the news arrived in the metals exchange that Chile was increasing production, speculators moved out of copper affecting its price. This last presentation initiated a heated debate over production policies with the intervention of all the speakers. The conference was closed by CESCO’s executive director Jorge Bande, who noted that this was the first time in Chile that a broadly-based group of private and governmental institutions had met to discuss copper development alternatives. Bande said that the seminar had given rise to a heightened awareness within the industry of the need for immediate action in the field of promotion and announced the formation of a task group in Chile to suggest policies to the government concerning Chile’s role in the copper industry. The proceedings of the seminar will be published by CESCO with the support of the Friedrich Ebert Foundation that also helped finance the event. For more information, contact CESCO, Lota 2267, of 204, Santiago, Chile.
Book review
very strong grasp of the quantitative techniques such as calculus of variations, optimal control, econometrics and Markov chain stochastic processes; the second, which is less explicit, is a belief that the complex and sensitive issues of forestry can be best handled by neoclassical models. These assumptions narrow down considerably the readers the book will attract. The intention here is not to criticize the relevance of neoclassical models and quantitative techniques in analysing natural resource issues, but only to mention that when a work is published in volume form, one expects its con-
THE
!==~NOMICS
OF FORESTRY
ANDNATURALRESOURCES Per Olov Johansson Lofclren Basil Blackwell, 305 pp, f29.50
and Karl Gustav
Oxford,
UK,
1985,
There are at least two requirements besides an interest in natural resources itself before a reader can appreciate fully this largely theoretical work from two Swedish forest economists, Johansson and Lofgren. The first is a
RESOURCES
POLICY March
1986
Juan O’Brien CESCO Santiago
reporrslBook
review
tents to appeal to readers beyond the academic researchers who, after all, have access to a range of academic journals incorporating models with their attendant proofs. One of the aims of a book on forestry economics, particulary from the academic profession, should be to bridge the comthe between munication gap academics and the policy makers who have less time and opportunity to be exposed to intellectual scrutiny of the subject. This book will hardly be one that the non-academician will find readable.
Many dimensions A problem of reviewing this book is that it covers many dimensions of forest economics as varied as optimal welfare rules for rotation criteria, forestry, cost-benefit propositions for forestry under unemployment, maximization of expected utility of a risk averse forester and many more. It is deep in some parts, superficial in others, and very demanding. If there was a common thread that guided the reader from one issue to another, the task of absorbing the contents would have been much easier. There is not even a concluding chapter that brings the disparate aspects of the various chapters together. The preface is no substitute as it is only a trailer of what to expect. While the first seven chapters flow in a reasonably cohesive manner, the last six seem to be disparate and lumpy. It appears as if the authors have been over-burdened with their research material, which might have been at home in a book of readings rather than being separated into various sections and chapters under the umbrella of the book’s title. Under these circumstances, the reviewer is forced to pick and choose those issues that he is competent in and feels are important, leaving the verification of the individual models and proofs to those readers who have the knowledge and time to scrutinize the various equations to judge their veracity. It has to be mentioned, however, that the various research pieces show analytical depth and dedication to the subject in their own terms.
79
Book review The first two chapters may be skipped by readers already familiar with non-renewable resource theory as expounded in some depth in a host of publications the most comprehensive being by Dasgupta and Heal.’ It was, however, Hotelling’s 1931 classic article that conceptualized the key issues of exploiting stock resources over time.’ The reason the authors start off with the economic principles of non-renewable resources is that they form the core of the theory of renewable resources. In some sense renewable resource theory is a special case of the theory of non-renewable resources, ie if one looks particularly in terms of an exploitation policy of a resource over time which maximizes the net present value of the income stream from the investment. There are some aspects in renewable resource exploitation which make it different from that of nonrenewable resources. One is growth, ie an addition to the net stock, and the other is age, ie the various vintages of the trees in the biomass. These two are interrelated. In forestry there are two kinds of harvests - thinning, to improve stand growth and cutting which is clear felling of the trees. Johansson and Lofgen ignore species classification as another dimension, which is more relevant to tropical forests than temperate forests, given the symbiotic relationship operating among the various species that affect the growth process, Another is the so-called ‘problem of the commons’ arising from common access to a resource which is usually given special treatment in renewable resource literature, particularly fisheries.” But this is in no way a particular problem of renewable resources. as the authors rightly point out. For instance, it is similar when an oil well is simultaneously exploited by two competing companies of different countries as in the North Sea. The ‘gold rush’ seen in earlier times did depict the ‘commons problem’ of producing a socially inefficient exploitation path. The complex dynamism of the forest resource over time together with its multiple uses both as a commercial activity as well as an integrated element of the ecosystem
80
makes the subject quite tricky for analysis. Given this somewhat ski generis character of forestry, are the neoclassical models that the book uses as its framework for analysis adequate to capture the salient factors for policy making? A review of the contents will show that the analysis has been only partial.
Forest rotation Chapters 3 to 8, which form the bulk of the study. delve into the problem of forest rotation, ie choosing an age at which trees ought to be thinned or harvested to maximize the present discounted value of profits. The authors start off with evaluation of an even aged forest under competitive conditions, developing the well known Faustmann formula (later refined by Pressler and Ohlin) that a forest stand shall be harvested when the rate of change of its value with respect to time is equal to the interest on the value of the stand plus interest on the value of the forest land. They investigate how the rotation period is affected by change in prices, wages and interest rates. The authors compare the Faustmann-Pressler-Ohlin formula with other harvesting criteria such as maximum sustained yield and allowable cut. The conclusions are not dissimilar to what has already been written.4 The authors do not, however, attack the maximum sustained yield concept (which is a favourite of some foresters) which is shown to be optimal at least from the assumptions adopted only if the interest rate is zero. This concept ignores all considerations of costs and prices. The issue is whether society can ever have a social time preference rate of interest that is zero, and if so is there any case for maximum sustained yield as a viable strategy in the context of a multi-aged, multi-species forest stand? If the interest rate is an important element, what interest rate is optimal for forestry? These practical issues with which policy makers and foresters grapple, sadly, are not discussed in any depth. Major policy debate on forest investment has been on the kind of discount rate that is
applied to cash flows in forestry - the market rate of interest that is applicable to other competing investments or the social time preference rate of interest which is lower. Another question is whether conservationists would be happier with sustained yield than with the Faustmann-Pressler-Ohlin formula of forest management if they have to make a choice? Chapters 5 and 6 consider the effects of different kinds of taxes on the rotation period and value of forest lands as well as changes in biotechnology. Other extensions include multiage trees, variable timber prices and varying rates of return. The conclusions are intuitively plausible and on the whole non-controversial if one accepts the assumptions of the model. Non-linearities of the specifications by and large, the authors find, do not disturb their results, although it is not clear if this would be the case if the market structure was not one of perfect competition. In Chapter 7 the authors analyse the behaviour of a self-employed farmer and the allocation of time between working in forestry, agriculture and industry, and the effect of taxes on leisure time. There are no surprises in the conclusions. The same can be said for the analysis of the forest industry as a forest owner. If the aim of the latter was to provide a demand function for round wood, one wonders whether there was not a simpler way.
Hotchpotch Chapter 8 is a hotchpotch of analyses that handle too many issues with tenuous links. They start off with defining the equilibrium conditions of a partial equilibrium aggregate supply and demand model; and jump to a section entitled ‘General equilibrium: few comments’ where they mention the possibility of integrating firms and consumers in an Arrow - Debreu type of model; this is followed by an analysis of a monopsonistic competitive market. This subject-hopping shows the jerkiness of the presentation. In subsequent chapters too the various research pieces ‘A bargaining approach to pricing of wood in Sweden’, ‘An
RESOURCES
POLICY March 1986
Book review/Conferences
econometric analysis of aggregate demand for and supply of wood in ‘Welfare theory and the Sweden’, optimal pricing of natural resources’, ‘Cost benefit rules for natural resources’, and ‘The properties of timber supply’, can stand individually on their own and, as mentioned earlier, might have stood out better as a collection of articles in a book of readings rather than in the present form. Cohesiveness of the book is as important as the cogency of the individual parts. Of these various pieces of research, the most interesting from the forest policy point of view is that of applying cost-benefit analysis to natural resources (Chapter 11). There are several complications, the authors conclude. The first which was mentioned in Chapter 3, but unfortunately was not developed further is ‘irreversibility in combination with uncertainty’. This forms the crux of the arguments of those who do not favour the rapid exploitation of tropical species, for their destruction could preclude all the potential benefits arising from future advances in biotechnology. The second is the multiple use of forest lands combining both commercial and non-commercial uses, with the latter non-marketed. This makes it difficult to apply the various conditions developed for optimal rotation and Pareto welfare optimality. The authors discuss whether ‘taking’, ie compensation by the gainers to the losers as a policy rule can lead to a Pareto superior situation, and conclude rightly that the economic criteria which they have developed may not handle these aspects. Choice must often be made on non-economic grounds. Unfortunately, noneconomic factors which are integral to the issues facing forestry today are not treated in any depth. It has to be stressed that economic factors cannot operate in a vacuum. The social, political and institutional environment is important. Another complication that has been picked up by the authors is unemployment although this is not only relevant to natural resources but to other sectors too. They consider whether the optimal rotation period can be relaxed
RESOURCES
POLICY March
1986
in the context of unemployment, and to the controversial conclusion that ‘unemployment (temporary or persistent) is not a sufficient condition to justify marginal departures from the Faustmann solution to the forest management problem’. This may be true if one applies strict financial criteria, using the assumptions of the model. If externalities and noneconomic factors are taken into account, can we expect conditions for achieving a Faustmann solution to be optimal? The costs of higher social security, increased policing and health care resulting from unemployment may outweigh any gains arising from the Faustmann optimal rotation solution. It has to be stressed also that an optimal harvest policy cannot effectively operate out of context of the social, political and institutional environment. one is tempted to ask Finally. whether this book poses and attempts come
to give answers to the key issues facing forestry today, ie the low level of replenishment of tropical forests, acid rain and other forms of pollution, non-wood substitution, the large resources required for sillicultural research and the need for a commodity agreement for wood to ensure longterm supplies? Unfortunately, it does not. Raj Kumar Commonwealth
Secretariat London
‘P. Dasgupta and G.M. Heal, Economic Theory and Exhausti6le Resources, James NisbeKambridge University Press, Oxford, 1979. *H. Hotelling, ‘The economics of exhaustible resourc&‘, Journal of Polifical Economy, Vol 39, 1931, pp 137-l 75. ‘C.W. Clark, Mathematical Bioeconomics: The Ootimal Manaaemenf of Renewable Resoukces, John Wiley, New York, NY, 1976. 4P.A. Samuelson, ‘Economics of forestry in an evolving society’, Economic Inquiry, Vol 14, 1976, pp 466-492.
Conferences of events is compiled from information provided by the respective organizers and from secondary sources. RESOURCES POLICY welcomes information on all conferences revelant to resources issues for listing in this section. The copy deadline is three months before publication. An asterisk denotes a new entry. This calendar
*12-14 March 1986, Boston, MA, USA Conference on THE ECONOMICS OF PRECIOUS METALS MANAGEMENT. Contact International Precious Metals Institute, Government Building. ABE Airport, Allentown. PA 18103, USA. “17-19 March 1986, Washington, DC, USA Energy Technology Conference and Exposition (ET’%). Details from Government Institutes. Inc, PO Box 1096, Rockville, MD 20850, USA. 17-20 March 1986, Jackson, Ml, USA 19% National Meeting of the AMERICAN SURFACE MINING AND RECLAMATION. Call for papers. Details from Dr Robert Knight. Range Science Department, Texas A-and M University. College Station, TX 77843, USA. 24 March4 April 1986, Falmouth, UK NATO Advanced Study Institute meeting on MINERAL PROCESSING AT THE CROSSROADS. Details from Dr B.A. Wills, AS1 Director, Cambourne School of
Mines, Pool, 3SE. UK.
Redruth,
Cornwall
TRlS
‘14 April 1986, Monte Carlo 7th Industrial Minerals International Congress. Please note this conference was originally scheduled to take place in Athens. Contact Diana Little, Deputy Product Sales Manager, Metal Bulletin Conferences Ltd, Pa;k House, Park Terrace, Worcester Park KT4 7HY, UK. *22-23 April 1986, Washington, DC, USA ENVIRONMENTAL LAWS AND REGULATIONS: INTRODUCTORY COURSE. Details from Government Institutes. Inc. PO Box 1096, Rockville, MD 20850, USA. 22-26 April 1986, Jakarta, Indonesia MINING INDONESIA. The second international mining and minerals recovery exhibition. Details from M. Ravner. Exhibition Manager, Overseas Exhibition Services Ltd, I1 Manchester Square, London WlM SAB.
81