The introduction of forests in cities has been an observable trend in recent years, with planned forest management projects proliferating around the world. The fact that many urban forests in the public space are traditionally managed by top-down bureaucratic procedures and guided by expert knowledge raises questions about whether green areas should follow the same management approach as other urban infrastructures, such as mobility infrastructures, or whether they should explore a collaborative approach designed to engage diverse stakeholders. This article examines the challenges of innovating in urban forests, changing the management rules that may limit participatory and deliberative processes to support decision-making. In particular, we analyzed how introducing a co-creation stage impacted the traditional competitive public tender procedure in the Madrid Metropolitan Forest project, using the Institutional Analysis and Development (IAD) framework. Results showed that the costs and benefits of innovation differ among involved actors, generating unintended deterrent effects for experimentation. To mitigate these decoupling effects, we suggest a strategic design of working rules and updating the shared incentive to move from a competitive and transactional logic to a more collaborative and co-creative form of connection.