Reducing Emissions from Deforestation and Forest Degradation (REDD+) is an ambitious global programme oriented towards improving forest carbon management. It aims to attract new sources of 'green' capital to fund emissions reductions from avoided deforestation and sustainable forest management. REDD+ is transforming forest conservation, as a diverse array of new stakeholders become involved. Not surprisingly, REDD+ has proved divisive, as critics concern themselves with issues of power, justice, and commodification, while practice-oriented researchers tackle similar issues from different perspectives, focusing on benefit sharing, safeguards, additionality, measuring and verification. In this paper we explore the different roles of critical and practical research, and argue that there is a need for greater sharing of knowledge across current divides. We draw on our own experiences of conducting a research project on REDD+ in Indonesia that involved critical and practice-oriented researchers. We argue that critical research disconnected from practical matters can have perverse outcomes for practitioners who are ultimately working towards similar goals; while uncritical practice-oriented research has the potential to lead to a dilution of core values of environmental justice and conservation. In contrast, forms of practical critique provide ways of researching REDD+ that have practical value while maintaining critical insights.