Bark fracture properties are thought to influence the debarking of selected trees by the African elephant. This hypo thesis was tested for large riverine tree species in the Northern Tuli Game Reserve, Botswana. An index of bark breakage strength and pliability of secondary phloem tissue was compiled for 11 common riverine species, and the bark anatomy of these species was investigated to determine relative fibrosity. The majority of species preferred by elephants have strong and pliable barks, associated with a high proportion of fibres. However, not all preferred species have these characteristics, which indicates that factors other than bark fracture properties affect species preference. Bark structure influences the way pieces of bark are stripped from a tree trunk during debarking. It is hoped that this paper will stimulate further studies on the effects of bark structure on the preferential feeding behaviour of the African elephant.