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Thomas Knoke - One of the best experts on this subject based on the ideXlab platform.
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Bioeconomic modeling of mixed Norway spruce—European beech stands: economic consequences of considering ecological effects
European Journal of Forest Research, 2013Co-Authors: Verena C. Griess, Thomas KnokeAbstract:The study provides an improved Bioeconomic model of mixed-species stands in order to test the economic consequences of tree species mixtures composed of spruce (Picea abies [L.] Karst.) and beech (Fagus sylvatica L.), when the impact of mixing tree species on stand resistance against hazards is considered. We used survival probabilities of spruce in mixed- and mono-species stands derived by Griess et al. (For Ecol Manag 267:284–296, 2012) to expand an existing Bioeconomic model by Knoke and Seifert (Ecol Model 210:487–498, 2008). Monte-Carlo simulations showed the highest average net present value (sum of all net revenues during one rotation period discounted by 2 %) for spruce stands with a small beech admixture of 7 % of total stems. The net present value of this mixed stand type was 8 % higher than that reached with a spruce monoculture, while risk—measured as standard deviation of net present value—was 18 % lower than that of a pure spruce stand. A mixed stand with 51 % beech led to a decrease of 23 % of the average net present value when compared to a spruce monoculture. However, the stabilizing effect of this high proportion of beech trees on spruce together with general economic diversification effects (as a result from low correlation of hazard and market risks of both tree species) reduced the standard deviation of the net present value by 55 %. Generally, an intensive species mixture in groups, with interactions between species throughout the stand, led to higher net present values and lower risks when compared to mixtures of identical proportions in large homogenous blocks without species interactions. For calculating survival probability, data from Rhineland-Palatinate were used, for modeling growth, data were based on information gained in Bavaria. It can be assumed that susceptibility toward windthrow was underestimated with respect to Bavarian conditions or growth was overestimated with respect to Rhineland-Palatinate conditions. This narrows the explanatory power of the study at hand and—once again—highlights the importance of a standardization of inventory processes all over Europe. Still the strong potential of mixing species is proven by the results. The hypothesis, derived from simpler, more traditional Bioeconomic Models that mixed-species stands are economically inferior to mono-species stands, could therefore be rejected. Of particular relevance to practicing foresters is the result that even mild admixtures may lead to substantial positive economic consequences. With relatively small initial investments then, a considerable increase in efficiency can be expected. This finding makes the admixture of at least small proportions interesting for the privately owned forest sector.
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integrating selected ecological effects of mixed european beech norway spruce stands in Bioeconomic modelling
Ecological Modelling, 2008Co-Authors: Thomas Knoke, Thomas SeifertAbstract:The simplicity of many Bioeconomic Models has been criticised several times, due to their lack of realism resulting from a deterministic nature and a single-species focus. In this context it was interesting to test the financial sensitivity of Bioeconomic modelling against fairly well documented ecological effects in mixed forests. For this purpose our study linked existing results of ecological research with Bioeconomic modelling. The presented methodological approach could not only show the importance of considering ecological effects in Bioeconomic Models; it in fact enabled prioritising ecological research from a financial point of view. In a first step, the possible influence of the tree species mixture on forest stand resistance, productivity and timber quality was derived from existing studies. In a second step, the available Monte Carlo simulations for Norway spruce (Picea abies [L.] Karst.) and European beech (Fagus sylvatica L.), simulated under site conditions and risks typical of southern Germany, were extended by the mentioned ecological effects and then evaluated from a financial perspective. The results showed a clear influence of all tested ecological effects on the financial indicators, financial risk and return. While testing each ecological effect separately, an increased resistance against wind, snow and insect attacks had the greatest influence on financial risk and return. It over-proportionally enhanced the financial return while simultaneously the financial risk was reduced. In contrast, a degraded timber quality could eliminate the positive effect of risk compensation in mixed forests almost completely. The least influence on the financial indicators finally showed a changed volume growth in mixed forests. A combination of the separately tested ecological effects (increased resistance, changed volume growth and decreased timber quality), between both tree species, underlined the dominating importance of the stand resistance. The integration of ecological effects, induced by interdependent tree species, in our Bioeconomic model resulted in significantly lower financial risk than ignoring these effects. Moreover, the financial return of mixed stand variants with a proportion of Norway spruce greater than 60% even exceeded that of the most profitable pure stand. In conclusion this paper clearly confirmed that ignoring ecological effects in Bioeconomic Models could lead to seriously biased financial results. While a changed volume growth proved rather to be of minor importance for European beech/Norway spruce stands, tree resistance and timber quality may change the financial results significantly.
Pierre-yves Le Gal - One of the best experts on this subject based on the ideXlab platform.
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Supporting policymakers in designing agricultural policy instruments: A participatory approach with a regional Bioeconomic model in La Réunion (France)
Land Use Policy, 1Co-Authors: Marie Dupré, Jean-marc Blazy, Thierry Michels, Pierre-yves Le GalAbstract:Abstract Bioeconomic Models make it possible to assess ex-ante the consequences of public interventions in the agriculture sector. Yet since policymakers rarely participate in their design or use, these Models are often too complex or do not address their questions. This article describes the implementation of a nine-step participatory modelling process involving regional policymakers, and analyses the contribution of this process to the cross-brainstorming between policymakers and researchers. In the preliminary stage, researchers develop a prototype Bioeconomic model which links the farm level, where trade-offs between productions are considered, with the regional level, where the balance between production and consumption per product is considered. Public actors are then mobilised to identify issues and characterise the scenarios that can be used to explore the questions selected. The scenarios are simulated with the Bioeconomic model, which evolves depending on the needs, and the outputs are discussed with the public actors. The method was applied in La Reunion (France) on the design and assessment of aid mechanisms related to the development of organic farming. The results showed (i) which farms convert to organic farming according to aid amounts, (ii) how local demand per product is satisfied and (iii) what are the amounts of the ensuing budgets for subsidies. The approach proved to be relevant for exchanging knowledge between public actors and researchers, regarding in particular innovative farming systems, farm diversity and multi-criteria evaluation of policy choices. The simulated scenarios offered powerful support for discussions about market evolutions and environmental challenges. These results indicate that transparent modelling tools and long-term partnerships with policymakers are required to implement such an approach at the regional scale.
Samuel Cameron - One of the best experts on this subject based on the ideXlab platform.
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The Economics Of Partner Out Trading in Sexual Markets
Journal of Bioeconomics, 2002Co-Authors: Samuel CameronAbstract:This paper derives a model of participation in what is commonly known as ‘adultery’. Arguably the best sex survey in the world is used to produce estimates of participation functions. The results show a great deal of support for Bioeconomic Models and reveal some interesting similarities and differences between the male and female equations.
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the economics of partner out trading in sexual markets
Journal of Bioeconomics, 2002Co-Authors: Samuel CameronAbstract:This paper derives a model of participation in what is commonly known as ‘adultery’. Arguably the best sex survey in the world is used to produce estimates of participation functions. The results show a great deal of support for Bioeconomic Models and reveal some interesting similarities and differences between the male and female equations. Copyright Kluwer Academic Publishers 2002
Duncan Knowler - One of the best experts on this subject based on the ideXlab platform.
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A Review of Selected Bioeconomic Models with Environmental Influences in Fisheries
Journal of Bioeconomics, 2002Co-Authors: Duncan KnowlerAbstract:Bioeconomic Models are integrated economic-ecological Models, with all the advantages and disadvantages of such Models. Most Bioeconomic modelling seeks appropriate levels of stock and catch to assist resource managers, normally with environmental conditions assumed constant. However, Bioeconomic Models can be used to analyse the welfare effects of changes in environmental quality as well. This latter application is the subject of this review. The review concentrates on the commercial harvesting of fish stocks, where population dynamics are influenced by environmental quality. In the first part of the paper, the basic static and dynamic Bioeconomic Models are described and then extensions are considered that take account of the influence of environmental quality on habitat and, by inference, on sustainable catch levels and measures of economic surplus. The second part of the paper describes a series of case studies from the empirical Bioeconomic literature that apply some of the theoretical innovations described earlier.
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A Review of Selected Bioeconomic Models with Environmental Influences in Fisheries
Journal of Bioeconomics, 2002Co-Authors: Duncan KnowlerAbstract:Bioeconomic Models are integrated economic-ecological Models, with all the advantages and disadvantages of such Models. Most Bioeconomic modelling seeks appropriate levels of stock and catch to assist resource managers, normally with environmental conditions assumed constant. However, Bioeconomic Models can be used to analyse the welfare effects of changes in environmental quality as well. This latter application is the subject of this review. The review concentrates on the commercial harvesting of fish stocks, where population dynamics are influenced by environmental quality. In the first part of the paper, the basic static and dynamic Bioeconomic Models are described and then extensions are considered that take account of the influence of environmental quality on habitat and, by inference, on sustainable catch levels and measures of economic surplus. The second part of the paper describes a series of case studies from the empirical Bioeconomic literature that apply some of the theoretical innovations described earlier. Copyright Kluwer Academic Publishers 2002
Viktoria Schneider - One of the best experts on this subject based on the ideXlab platform.
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the Bioeconomics of marine reserves a selected review with policy implications
Journal of Bioeconomics, 2005Co-Authors: Quentin R Grafton, Tom Kompas, Viktoria SchneiderAbstract:The paper ‘bridges the divide’ between the biological and economic literature on marine reserves. It provides a selected review of the traditional use of reserves, the early reserve literature, the potential benefits of reserves, spillovers from reserves to harvested areas and Bioeconomic Models of marine reserves. The Bioeconomics literature is examined from the perspectives of deterministic Models, spatial economic Models and Models that include uncertainty and stochasticity. Insights from the review are used to provide management implications in terms of reserve design, stakeholder cooperation and process, reserve-fishery transfers, traditional management controls, and ecosystem approaches to managing fisheries. Copyright Springer 2005
