The story
As the tale is told, a village troubled by childlessness sent its women, one by one, to ask the spirit dwelling in a great iroko tree for children, each woman promising a gift in return: goats, yams, cloth, whatever she had to offer. A woman named Oluronbi, who had nothing comparable to give, promised the spirit her first child instead, and the spirit accepted. When her child was born, Oluronbi and her husband found they could not bear to give him up, and the story tells of the tree spirit's anger at the broken promise.
Yoruba communities that tell this story mark it with an annual festival tied to a stream where an iroko tree stands, cleaning the water source amid work-songs, chants, and drumming, and a version of Oluronbi's story is still sung as part of that observance.
Why it travels with the drum
The tale is retold here as cultural background to the wood rather than as a claim within Santo Daime practice: it reflects the standing the iroko tree holds in the Yoruba communities where bougarabou drums are carved, and helps explain why the wood carries more than practical value for the carvers who choose it.