LAUSR

Abstract There is increasing political interest in the use of voluntary agreements (VA) as a policy instrument. The attraction has grown also in environmental policy, VAs are expected to be less costly, more effective and more cost-efficient than regulation. Using a realist review methodology, our analysis focuses on the effect of contextual factors and mechanisms on private forest owners' willingness to enter into formal voluntary nature conservation agreements. The framework we use to analyse the effects includes: forest owner characteristics, forest attributes, institutional context and process, advisors and other forest owners, and contract design, for contextual factors – and economic attitudes, environmental attitudes, sense of autonomy, sense of justice and fairness, trust as well as knowledge, for mechanisms. The analysis allowed merging findings from different types of VAs in varying contexts in a systematized way, and consolidating evidence of how the mechanisms influence the programme implementation process, and its outcome. 43 reviewed articles, from an originally retrieved set of 2231 papers, provide evidence for environmental attitudes supporting willingness to enter into an agreement. Environmental attitudes are strengthened by forest owners' wishes to protect a heritage, suggesting considerable influence through personal, emotional attachment to the forest. This finding shows the central role played by sense of autonomy, with economic compensation also importantly affecting the willingness to enter a VA. Along with these results, the developed comprehensive analytical framework shows how VAs can become more effective if tailored for different contexts and types of forest owners.