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51.
The multiple effects of carbon values on optimal rotation   总被引:2,自引:0,他引:2  
Non-consumptive benefits which increase with crop age, like keeping carbon sequestered, lengthen optimal rotation compared with rotation for timber alone. High proposed carbon prices may extend rotation indefinitely. Carbon storage in wood products reduces this tendency. Biomass as an energy source displacing fossil fuels favours rotations near those of maximum biomass productivity. Use of sawn timber to displace structural materials with high embodied carbon favours somewhat longer rotations. Effects of rotation on soil carbon, and fossil carbon volatilised in harvesting operations, are further complications. Including all carbon effects results in optimal rotations somewhat longer than those based only on timber value, but shorter than those based on timber plus forest carbon. To include all factors intuitively is not possible: balanced appraisal needs economic calculations.  相似文献   
52.
In recent years it has been argued, from many perspectives, that the further into the future a value flow occurs, the lower is the appropriate discount rate for it. National governments are now beginning to authorise such declining discount rates. This viewpoint can be, and has been, formalised in various ways, and has been applied to evaluating forestry investments of given durations. When the optimal duration of investment is itself the issue, new problems arise. Lower discount rates make subsequent rotations longer than earlier ones, and for a given length more valuable than they would otherwise be. This affects the optimal length of earlier rotations, which in turn may affect the discount rate profile applicable to later ones. In the absence of analytical solutions for the optimal sequence of rotations, numerical protocols are needed. The results arising are mostly in accord with expectations. If the change of discount rate is due to expected changes of circumstance that are actually realised, then the optimal sequence of rotations will remain as initially determined. If, however, it is due merely to the particular time perspective of the present generation, rotations will be revised by future generations. This will lead to a sequence of rotations similar to that deemed optimal at the current short-term discount rate. The most important reductions in profitability caused by choosing the “wrong” discounting protocol arise from the “wrong” rate, rather than by using declining rates as such.  相似文献   
53.
The role of traders and traditional exchange institutions has received little attention in empirical research on rural markets in developing countries. We use detailed data on transactions in a village commodity market in India and identify two observed anomalies: first, the repeal of the law of one price, and second, a trader‐idiosyncratic effect, namely that large volumes are sold to a trader who does not offer the best price. Econometric analysis demonstrates that trader idiosyncrasy can largely be explained by reciprocity motives in interlocked village markets. Reciprocity leads to market inefficiencies and can result in unexpected supply responses.  相似文献   
54.
For countries with recurrent droughts, the design of drought impact mitigation measures could benefit from analyses of determinants of yields and prices of local crops at regional and district level. This study applies dynamic spatial panel data regression models to yields and prices of four major food crops across regions of Burkina Faso and Niger, over sample periods between 1984 and 2006. Results lend support to mainly simultaneous spatial spillovers, particularly for millet and cowpea prices and sorghum yields in Niger, and maize yields in Burkina Faso. After accounting for these effects, most crop yields are found to be weakly price‐responsive, as envisaged by a supply‐side geographical diffusion hypothesis. Seasonal rainfall elasticity estimates suggest that dominant food crops have slight advantage margins in terms of relative resilience to rainfall shortages. However, this result is to be weighed against low millet yields in Niger, and marked drops in sorghum yields during officially declared droughts in Burkina Faso.  相似文献   
55.
The objective of this article is to analyze the domestic and international effects of a hypothetical foot‐and‐mouth disease (FMD) outbreak in the Mexican cattle industry. A discrete time dynamic optimization model of the Mexican cattle sector is specified, and linked to domestic and international markets. Economic consequences of FMD outbreaks are simulated over time and under different scenarios. Specific findings and general policy recommendations are provided. The study reports a range of outbreaks from localized to large scale and suggests that changes in economic surplus due to FMD range from a positive net gain of $0.89 to $1.6 billion to a net loss of about $67 billion, depending on the specific mitigation strategy and outbreak scenario.  相似文献   
56.
A number of problems in agricultural economics involve modeling joint distributions for which the assumption of multivariate normality may not be warranted. Yet, very little work has been conducted evaluating competing methods for modeling joint dependence. We develop a simulation framework to evaluate the bias and efficiency impacts of copula choice in the context of evaluating county‐to‐farm basis risk. The results suggest significant differences in performance across various copulas and approaches. The findings have important implications for risk analysis, insurance, and policy modeling problems in agriculture regarding the selection of method to model dependence among random variables.  相似文献   
57.
Biofortification of maize with provitamin A carotenoids is a new approach to the alleviation of vitamin A deficiencies in Africa. Unfortunately these varieties are yellow or orange, while consumers generally prefer white. Consumer willingness to pay for yellow and fortified maize was compared in experimental auctions in three regions in Kenya. The premium that consumers are willing pay for fortified maize (24%) was higher than the discount they require to buy yellow maize (11%), and in one zone consumers prefer yellow. Yellow color is, therefore, not an impossible obstacle for biofortified maize, although it would clearly be easier to introduce this maize first in regions where yellow maize is currently grown.  相似文献   
58.
Using survey data collected in multiple locations (California and Texas in the United States and Revohot in Israel), we quantify category‐ and location‐specific variations of consumers’ willingness to pay (WTP) for brand products after controlling for consumer characteristics. We find that consumers have a similar qualitative assessment of brand value in different product categories across different locations. That is, consumers have a stronger preference and higher WTP for brands in consumer electronics, followed by clothing and then processed food, and the lowest in fresh produce. Furthermore, we simulate price premiums and market shares of brands relative to generic products in different categories. Simulation results suggest that brands in fresh produce have the highest price premium but lowest market share. Despite the similarities, the magnitude of WTP for brands as well as the simulated price premium and the corresponding market share in the same product category are location variant. The similarities and dissimilarities suggest validity of having global brand strategies adapted to local conditions, that is, the so‐called “thinking globally and acting locally” strategy.  相似文献   
59.
Theoretical models of market entry imply that sunk costs are an important factor in the decision to export. Following Helpman, Melitz, and Rubinstein (2008) , we develop a simple model of foreign market participation and use a Bayesian method to estimate the resulting dynamic discrete‐choice model with lagged dependent variable. Employing a balanced panel data that follows 81 trading partners for 30 years from 1971 to 2000, we estimate our model and compute the marginal effect of sunk costs on the likelihood of export market participation. We find that such costs are economically and statistically important for trade in all of the six major agricultural commodities (Cereals, Dairy, Fish, Meat, Vegetables and Fruits, and Sugar), for agricultural producers in both developed and developing countries. We also find evidence suggesting that, in general, market access for both developed and developing exporters had improved in the years following the Uruguay round of trade negotiations (1995–2000).  相似文献   
60.
EU enlargement and the recent sovereign‐debt crisis of Euro zone countries have revived the debate around the (European Monetary Union) EMU. In this article we ask how informal barriers to agricultural and food trade have changed since the introduction of the common European currency, and whether this evolution can be attributed to monetary integration. We focus on the foreign trade of the 11 EMU founder countries over a nine‐year period covering the creation of the EMU and find a diminishing marginal trade impact of both information and institutional barriers. We find a lower level of trade barriers, but cannot attribute this outcome to the introduction to the Euro.  相似文献   
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