One of the ca. 800 species of acacias, this tree is not indigenous to Senegal. For economic reasons, it was planted on the banks of River Senegal by the Arabs during their expansion that occurred from the 8th to the 16th century. Acacia senegal was exploited for its exsudate. When the bark is incised with a knife, a gum is secreted to seal the gash and prevent dehydration which, in that climate, would kill the tree. The resulting gum arabic, half a pound per tree on the average each year, gave rise to a lucrative trade with Europeans. The Dutch, the English and the French sought it avidly for their silk manufactures to stiffen fabrics. They sent ships to the coasts of Mauritania and Senegal for this precious commodity. Gum arabic was so valuable that its commerce was at times more rewarding than the slave trade. The three European countries fought naval wars against one another during the eighteenth century over monopoly of the trade.
My book, in French, Copal benjoin colophane … , Le Pommier, Paris, 2007 tells the story of the Gum War between France and England.