Decisions related to the use of genetically modified (GM) forest trees could be more rational if they would take into account socio-economic considerations in addition to environmental risk assessment. This chapter presents an overview of available socio-economic approaches and tools for assessment of GM forest crops and presents options for their implementation. In particular, it explores the suitability of Cost-Benefit Analysis (CBA), a well-known method in the field of economics, for aiding the decision-making process that regulates the experimental and/or commercial release of GM forest crops. A generic catalogue of potential positive and negative externalities that can reasonably be expected as a result of commercial application of GM forest trees and which are specifically connected to modified traits was compiled to form the basis for CBA. Cost and benefit variables were grouped according to two criteria (i) the sustainability type of variables, namely environmental, economic and social variables and (ii) the affected party. The latter is particularly useful as it is related to the distributional equity of costs and benefits of GM forest trees. Finally, results from a focus group study that was organized as part of COST Action FP0905 in order to identify the most important positive and negative externalities of GM forest plantations in connection to modified traits is also presented. CBA can make a significant contribution to a more rational decision-making process towards the potential release of GM forest trees, as it would add a measure of potential contributions to social welfare. However, further research is required to provide more information on the range of potential positive and negative externalities, their quantification, and predictions at different spatial and temporal scales.
