Forest Value and Optimal Rotations in Continuous Cover Forestry

The Faustmann forest rotation model is a celebrated contribution in economics. The model provides a forest value expression and allows a solution to the optimal rotation problem valid for perpetual rotations of even-aged forest stands. However, continuous forest cover forest management systems imply uneven-aged dynamics, and while a number of numerical studies have analysed specific continuous cover forest ecosystems in search of optimal management regimes, no one has tried to capture key dynamics of continuous cover forestry in simple mathematical models. In this paper we develop a simple, but rigorous mathematical model of the continuous cover forest, which strictly focuses on the area use dynamics that such an uneven-aged forest must have in equilibrium. This implies explicitly accounting for area reallocation and for weighting the productivity of each age class by the area occupied. We present results for unrestricted as well as area-restricted versions of the models. We find that land values are unambiguously higher in the continuous cover forest models compared with the even-aged models. Under area restrictions, the optimal rotation age in a continuous cover forest model is unambiguously lower than the corresponding area restricted Faustmann solution, while the result for the area unrestricted model is ambiguous.     

Forest management: Are double or mixed rotations preferable to clear cutting?

We study a particular uneven-aged forest stand management pattern, variations of which are often advocated in practice to mitigate the adverse effects of clear cutting. The forest stand under consideration is similar to a Faustmann stand, with the following difference: rather than being single aged, the forest tract contains trees of two age classes so that it is submitted to a form of selective cutting. Each harvest involves all of the older trees and only a fraction of the younger ones; hence the name mixed rotation. Trees left standing at harvest help stimulate natural regeneration and improve various environmental and amenity characteristics of the forest. We model this effect by using a cost function that varies with respect to the harvest rate of younger trees. We derive the properties that this cost function must exhibit in order some form of mixed rotation to be superior to the conventional single rotation à la Faustmann; we also characterize the mixed rotation in terms of duration and the harvest rate of younger trees, and we compare its properties with Faustmann’s rule.     

On the faustmann solution to the forest management problem

This paper is concerned with optimal solutions to the forest management problem when future utilities are undiscounted. By examining asymptotic properties of such solutions, we find that (i) if the utility function is linear, then the Faustmann periodic solution is optimal; (ii) if the utility function is increasing and strictly concave, an optimal solution converges to the maximum sustained yield solution, which we characterize as a golden rule. These results may be viewed as a possible resolution to the debate in forestry economics about what constitutes an optimal policy in forest management.     

Carbon sequestration and the optimal management of New Hampshire timber stands

This paper explores the tradeoff between resource extraction and net carbon sequestration in managing representative timber stands in the state of New Hampshire in the northeastern United States. In the absence of policies to promote forest carbon storage, land owners have incentives to employ clear-cut harvesting regimes with relatively short rotation periods. Under conservative assumptions regarding the social benefits of carbon storage, optimal rotation periods are extended by between 16 and 133 years depending on the forest type under consideration. If policy-makers pursued a cost-effective strategy to stabilize atmospheric carbon dioxide concentrations at twice the pre-industrial norm, optimal rotation periods would be extended by a full 180–347 years. The analysis suggests that partial harvesting regimes (in which approximately 35% of timber volume is removed at 15-year intervals after the timber stand reaches an initial age of 45 years) provide relatively high net benefits under a variety of circumstances. This finding is relevant because partial harvesting is an accepted and relatively common practice that could be adopted more widely.     

Management of an annual fishery in the presence of ecological stress: The case of shrimp and hypoxia

The emergence of ecosystem-based management suggests that traditional fisheries management and protection of environmental quality are increasingly interrelated. Fishery managers, however, have limited control over most sources of marine and estuarine pollution and at best can only adapt to environmental conditions. We develop a bioeconomic model of optimal harvest of an annual species that is subject to an environmental disturbance. We parameterize the model to analyze the effect of hypoxia (low dissolved oxygen) on the optimal harvest path of brown shrimp, a commercially important species that is fished in hypoxic waters in the Gulf of Mexico and in estuaries in the southeastern United States. We find that hypoxia alters the qualitative pattern of optimal harvest and shifts the season opening earlier in the year; more severe hypoxia leads to even earlier season openings. Failure to adapt to hypoxia leads to greater losses when the effects of hypoxia are more severe. However, rent gains from adapting fishery management to hypoxia are relatively small compared to rent losses from the hypoxia effect itself. This suggests that it is critical for other regulatory agencies to control estuarine pollution, and fishery managers need to generate value from the fishery resources through other means such as rationalization.     

Fishing Technology and Optimal Distribution of Harvest Rates

This paper examines the problem of the optimal management of a joint-ownership fishing exploitation, where agents use different fishing gears. We consider a model in which the fishing activity may affect resource growth, not only through the harvest function but also through the natural growth rate of the resource. This allows us to capture the fact that some fishing gears alter the natural growth rate of the resource. We find that when the natural growth of the resource is altered by the fishing technology, the optimal stock is not independent of how harvest quotas are distribute among the agents. As a result, a fishing policy that firstly determines the optimum stock and, secondly, decides how to distribute the harvest among the different agents, will not be efficient. We also analyze the joint determination of optimal stock and harvest quotas and show that positive harvest quotas will only be optimal when countries are characterized by certain asymmetries.     

Optimal Harvesting of an Age-Structured Schooling Fishery

Biologists have criticized traditional biomass models in fishery economics for being oversimplified. Biological stock assessment models are more sophisticated with regard to biological content, but rarely account for economic objectives. This study includes a full age-structured population model for studying schooling fisheries and extends the delayed difference approach used in earlier studies. We take the total harvest as the choice variable, resulting in a simple analytical structure. The model produces optimal steady states that may be higher or lower compared to the delayed-difference formulation. The model is applied to the Baltic sprat fishery. Both ecological and harvesting cost data support specifying Baltic sprat as a schooling fishery. Given nonlinear harvesting costs, the optimal solution is a path toward a steady state with smooth annual harvest and population age structure. Sensitivity analysis shows that the optimal solution is highly dependent on the population level of the sprat’s main predator Baltic cod. A linear cost function and an interest rate below 9 % imply pulse fishing instead of smooth continuous harvesting. Given nonlinear harvesting cost, the optimal steady state yield is rather insensitive to changes in the interest rate. However, under a high cod scenario, interest rates of 10 % or higher implies that no optimal steady state exists.     

Harvest and extinction in multi-species ecosystems

A potential cost of harvesting in multi-species ecosystems is the extinction of nonharvested species that are at the same trophic level as the harvested species. Existing analytical models are not well-suited for studying this harvest externality because they focus on species interactions across trophic levels instead of within them. We identify the conditions under which the harvesting of a single species causes at least one extinction of nonharvested species at the same trophic level. We compare two harvest regimes: uniform management, in which a privately optimal harvest rate is applied to the entire ecosystem; and specialized management, in which a portion of the ecosystem is intensively managed for the harvested species and the rest is left unharvested. Which regime is more likely to result in extinction depends on the discount rate and on the harvested species' competitive ability and colonization rate compared to those of the other species.     

The optimal control of emissions and renewable resource harvesting under uncertainty

A model of a renewable resource is developed where the growth and quality of the resource are reduced by pollution. Ambient pollution concentrations and the renewable resource stock are modeled as stochastic processes. Conditions for the optimal harvest plan and the optimal emissions rate are derived. The effect of stochastic variations on the optimal management of the resource is analyzed. The steady-state joint probability distribution of the resource and pollution stocks is shown to exist under certain conditions.     

The impact of recycling on the long‐run forestry

Abstract Interest in recycling of forest products has grown in recent years, one of the goals being to conserve trees or possibly increase their number to compensate for positive externalities generated by the forest and neglected by the market. This paper explores the issue as to whether recycling is an appropriate measure to attain such a goal. We do this by considering the problem of the private owner of an area of land, who, acting as a price taker, decides how to allocate his land over time between forestry and some other use, and at what age to harvest the forest area chosen. Once the forest is cut, he makes a new land allocation decision and replants. He does so indefinitely, in a Faustmann‐like framework. The wood from the harvest is transformed into a final product that is partly recycled into a substitute for the virgin wood, so that past output affects the current price. We show that in such a context, increasing the rate of recycling will result in less area being devoted to forestry. It will also have the effect of increasing the harvest age of the forest, as long as the planting cost is positive. The net effect on the flow of virgin wood being harvested to supply the market will as a result be ambiguous. An important point, however, is that recycling will result in fewer trees in the long run, not more. It would therefore be best to resort to other means if the goal is to conserve the area devoted to forestry.     

Fisheries Management Under Cyclical Population Dynamics

Cycles in environmental conditions (e.g., sea-surface temperature) directly impact fish growth. This paper extends the classical Gordon-Schaefer fishery model by replacing the constant growth rate with a cyclical growth rate. The optimal harvest rate is shown to fluctuate, but the cycle of the harvest rate lags the cycle of the biological growth function with the highest harvest rate occurring after biological conditions start to decline. Simulations contrast various fishing policies and illustrate the proclivity to crash a fishery if it is wrongfully managed as if there is a constant growth rate with i.i.d. environmental shocks. Finally, we show that small cyclical fluctuations in one species can result in large fluctuations in the optimal harvest rate of another species if the fish species are interlinked through predator-prey relationships.      

Optimal control of a multi-cohort fishery

Models of optimal renewable resource exploitation typically assume an equation for total population growth over time irrespective of the age distribution of the stock. By means of the theory of parametric optimal control, this paper outlines a model of a fishery with population varying in both age and time. Instead of an optimal steady-state harvest we derive an optimal harvest age distribution with lower utilization of younger members of the population.     

Common factors in Latin America's business cycles

We develop a common factor approach to reconstruct new business cycle indices for Argentina, Brazil, Chile, and Mexico (“LAC-4”) from a new dataset spanning 135 years. We establish the robustness of our indices through extensive testing and use them to explore business cycle properties in LAC-4 across outward- and inward-looking policy regimes. We find that output persistence in LAC-4 has been consistently high across regimes, whereas volatility has been markedly time-varying but without displaying a clear-cut relationship with openness. We also find a sizeable common regional factor driven by output and interest rates in advanced countries, including during inward-looking regimes.     

Counterparty effects on capital structure decision in incomplete market

This paper builds a static contingent-claim model that allows for examining the optimal capital structure with the joint arguments of counterparty default risk and market incompleteness. A first-passage-time model with jump default barrier is adopted to capture the counterparty effects on the pricing of defaultable claims. Following the framework of Jarrow and Yu (2001), the jump in primary firm's bankruptcy barrier is designed as the loss on capital resulted from secondary firm's bankruptcy. The relevance of market incompleteness in the context of claim-pricing is considered using “good-deal asset price bound” method by Cochrane and Saa-Requejo (2000). We show that the effects of counterparty's default clearly diminish the uses of debt, which indirectly explains the so-called under-leveraged puzzle. We further find that counterparty effects on capital structure are sensitive to market incompleteness and firm's characteristics, such as tax rate and bankruptcy cost rate.     

OPTIMAL MONETARY POLICY WITH THE STICKY INFORMATION MODEL OF PRICE ADJUSTMENT: INFLATION OR PRICE‐LEVEL TARGETING?

I investigate the optimal monetary policy in a New Keynesian macroeconomic framework with the sticky information model of price adjustment. The model is solved for optimal policy, and welfare implications of three alternative monetary policy regimes under this optimal policy are compared when there is a cost‐push shock to the economy. These monetary policy regimes are the unconstrained policy, price‐level targeting and inflation targeting regimes. The results illustrate that optimal policy depends on the degree of price stickiness and the persistence of the shock. Inflation targeting emerges as the optimal policy if prices are flexible enough or the shock is persistent enough. However, the unconstrained policy or price‐level targeting might be preferable to inflation targeting if prices are not very flexible and the shock is not very persistent. The results also show that as prices become more flexible, the welfare loss usually gets bigger.     

Radiative forcing and the optimal rotation age

Forests help mitigate climate change by sequestering atmospheric carbon. However, boreal and high-latitude temperate forests may also contribute to global warming due to the albedo effect. The relative effects of carbon sequestration and albedo can be quantified in terms of radiative forcing. We present a stylized, stand-level analysis to determine the optimal rotation age when considering a tax/subsidy scheme based on radiative forcing and the notion of equivalent carbon emissions. Additional management decision variables considered include species choice and regeneration effort, since these can impact the albedo effect. We demonstrate analytically that the optimal rotation length is likely shortened when albedo-related equivalent emissions are incorporated, relative to a policy based only on carbon. Empirical results indicate that rotation ages do decrease relative to a “carbon only” policy, and approach the traditional (timber only) Faustmann rotation age as equivalent emission rates increase. Our results suggest that forestation does not necessarily provide climatic benefits in all circumstances, and that, at the margin, other opportunities for carbon reduction (e.g. abatement), or pursuing forestation in other locations, become more attractive.     

Cannibalism and the Optimal Sharing of the North-East Atlantic Cod Stock: a Bioeconomic Model

This paper shows how intra-stock relations such as cannibalism and growth enhancement, determine the economically optimal sharing of a fish resource between heterogeneous harvesting agents. The sharing of resources between different vessel groups is often left for political decision making. Nonetheless, such decisions may have both biological and economic consequences. This becomes quite clear when different harvesting groups exploit different sections (age groups) of a stock that has intra-stock interactions in the form of cannibalism. A two-agent bioeconomic model with cannibalism is developed and used to determine (i) optimal annual harvest sizes (TACs) for cod, and (ii) the optimal proportion of the TAC that should be harvested by the different vessel groups in the fishery. Applying biological and economic data in a numerical procedure, and comparing the results obtained to previous studies, it is shown that intra-stock interactions such as the presence of cannibalism has a significant impact on who should take what proportion of the TAC, and hence, the standing stock size and discounted economic rent achievable. In contrast to other studies, we find that the optimal harvest requires that both trawlers and coastal vessels should harvest the fish resource. In addition, the results indicate that, from a bioeconomic perspective, the existing trawler fleet’s harvest share in the cod fishery is too high. This revised version was published online in August 2006 with corrections to the Cover Date.     

Parameter Uncertainty in CGE Modeling of the Environmental Impacts of Economic Policies

Political and economic factors usually determine the harvest sharesallotted to heterogeneous fisher groups harvesting upon the same fishstock. Given that the fishers harvest upon different segments of a fishstock with, for instance, cannibalistic tendencies, the shares allottedmay have considerable effect upon the well-being of the stock and theeconomics of the fishery. This paper analyses an existing allocationrule defining harvest shares allotted to two vessel groups (trawlers andcoastal vessels) in the Norwegian cod fishery. We apply a model with twointeracting age groups within a single fish stock, where the interactionhas both biological and economic implications. Requiring a first bestapproach to an optimal stock size results in no harvest in the firstyears studied. In order to ensure harvest amounts close to the historicharvest, we design a second best model giving optimal biological sharesin the build-up phase of the stock, and bioeconomic optimal shares atthe optimum fish stock level. The second best model recommends that foran increasing stock size the trawlers should obtain decreasing shares.We find that the actual allocation rule functions in a manner oppositeto the second best model, since this rule allocates an increasing shareto the trawlers for an increasing stock size.     

Optimal fishery harvesting rules under uncertainty

This paper derives the optimal fishery harvest policy in a real-option model with a stochastic logistic growth process, harvest-sensitive output price, and both fixed and variable harvesting costs. The policy specifies the harvest trigger and harvest size, while outputs from the model include the value of the fishery and the risk of extinction. The optimal policy is illustrated with data from the Pacific Halibut Fishery. For this particular case, the optimal policy recommends harvesting when the fish stock rises to about three-quarters the environmental carrying capacity, and the amount harvested should be approximately a quarter of the prevailing stock. This harvesting policy maximizes the value of the fishery, and importantly, the resulting risk of extinction is negligible. We also carry out some sensitivity analysis to see how the optimal policy (and the resulting fishery value and risk of extinction) change when the input parameters are varied, particularly the ecological parameters intrinsic growth rate and volatility of the stock, and also the economic parameters that have been ignored in previous papers (price sensitivity and fixed cost). If the optimal policy is followed, the risk of extinction will be negligible, except for very low growth rate and high volatility.     

Extracting portfolio management strategies from volatility transmission models in regime-changing environments: Evidence from GCC and global markets

Unlike previous studies, this paper uses the Multi-Chain Markov Switching model (MCMS) to examine portfolio management strategies based on volatility transmission between six domestic stock markets of Gulf Arab states (GCC) and global markets (i.e., the U.S. S&P 500 index and oil prices) and compares the results with those of the VAR model. Our volatility approach is range-based and not return-based which is traditionally used in estimating the optimal hedge ratios and portfolio weights. The results demonstrate the relative hedging effectiveness of the MCMS model compared to the VAR. We also highlight the time and regime dependency of the optimal hedge ratios and the portfolio weights for each selected pair of the considered markets conditional on the regime of the same market and the regimes of the other market. Policy implications on portfolio strategies under different states are also discussed.