This paper explores perceptions of health, the environment, and the relationships between them, in a programme of community forestry. Drawing on qualitative data generated within a multi-disciplinary project, the paper discusses the difficulties of conceptualising the key variables utilised in research on the links between green space and health. Health and the environment were not discrete entities that could be mapped on to one another, but fluid and contested concepts. A simple model of the 'impact' of environment on health could not do justice to the ways in which 'use' of outdoor space is a process, not an event.