Scope insensitivity in contingent valuation of complex environmental amenities

It has been argued that respondents in contingent valuation (CV) surveys, asked to value complex environmental amenities, will state willingness to pay (WTP) independently of the scope of the project. Such insensitivity to scope would be at odds with rational choice, and could therefore imply that CV is not a theoretically valid method for biodiversity valuation. The scope test in the present CV study was applied to endangered species preservation. Respondents were split in four sub-samples facing different scopes of endangered species preservation. The design allowed for both external and internal scope tests. Furthermore, the tests were split according to elicitation format. Of four external tests of insensitivity to scope, one was rejected, two gave mixed results, depending on either the type of test or elicitation format, and for the last one the null hypothesis could not be rejected. Of five internal tests, insensitivity to scope was rejected in three cases, one test gave mixed results, and one could not be rejected. Survey design features of the CV study, especially an unfamiliar sub-group of endangered species, could explain the apparent insensitivity to scope observed.     

The Role of Wood Material for Greenhouse Gas Mitigation

Based on an interdisciplinary perspective the role of wood as a carbon sink, as a multi-purpose material, and as a renewable energy source for the net reduction of greenhouse gases is discussed. We synthesize aspects from engineering, natural and social sciences to better understand the role of wood substitution in CO₂ mitigation. We also formulate some recommendations on filling knowledge gaps that could be useful for policy making regarding how wood substitution could be further expanded. There are sufficient wood resources to substantially increase the use of wood for material and energy purposes. However, a number of factors hinder a wider use of wood for energy and material purposes. Furthermore, an analysis of wood substitution is a very complex issue, since the substitution influencing factors are to be found along the entire wood supply chain and involve several industries, socio-economic and cultural aspects, traditions, price dynamics, and structural and technical change. To improve the knowledge about wood as a substitute for other resources and the implications, it would be helpful to better integrate research from different disciplines on the subject and to cover different scales from a project to an economy-wide level.