This article discusses the practice of crossdisciplinarity in the context of future-oriented sustainability studies. Much research into crossdisciplinarity has concentrated on programmatic and epistemological questions. In this study, we focus on research practice and efforts to realize transdisciplinary aims across a research programme. We use the Swedish Future Forests programme as a case study and explore its aims, forms of collaboration and level of conceptual integration. The study demonstrates that efficient integration requires organizational settings able to support the development of a common conceptual framework. To achieve this, the aims and forms of collaboration and the means of integration ought to be consistent. Far-reaching integration and short-term instrumental objectives may be difficult to combine because integration requires intellectual space, specific boundary settings and time. Short-term instrumental objectives may also hamper open and reflexive discussion of alternative pathways to sustainability and of how participating actors shape the research process. These insights may help researchers and participating actors to design research programmes that enable a realization of their transdisciplinary ambitions.