The butter is processed from the trees' nuts, which have been the focal point of research led by UO anthropologist Daphne Gallagher. Her team has been digging up the history of shea trees at a well-preserved archaeological site at Kirikongo in western Burkina Faso.

The long history of people nurturing shea trees, Gallagher reports in a paper published this month in the Journal of Ethnobiology, goes back 1,000 years earlier than researchers had previously assumed. After examining layers of households built on top of one another for some 1,600 years, Gallagher's team says local residents have been processing the nuts since at least A.D. 100.

"Our findings demonstrate the antiquity of the use of this particular resource," said Gallagher, a lecturer in the Department of Anthropology. "It demonstrates the importance of wild foods in early agricultural diets, and that its importance has continued through time."

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