There is increased international interest in religiously based restrictions on land and forest stand use. However, the extent to which so-called sacred groves represent earlier forest ecosystems, and their possible role in biodiversity conservation, are interrelated and complex issues, and neglected in the context of Ghanaian savannahs, which are believed to be in transition from a forested past. Geographical information system (GIS) analysis of time-series images, aerial photographs, statistical analysis of ecological field data and social surveys were used to investigate the Ghanaian savannah. Sacred groves were found to be similar in plant species content and structure to the deciduous forest of southern Ghana. Between 1960 and 1996, these groves experienced far fewer forest losses than unprotected tree stands (<20%, as opposed to up to 100%). Non-sacred groves also contained lower plant species richness and higher numbers of invasive species such as neem (Azadirachta indica A. Juss). Sacred groves, while dependent on respect for religion, local cultural structures and individual peer pressure, offer a role that may support and also be supported by official conservation efforts.