BARK STRUCTURE AND PREFERENTIAL BARK UTILIZATION BY THE AFRICAN ELEPHANT

Bark fracture properties are thought to influence the debarking of sel ected trees by the African elephant. This hypothesis was tested for la rge 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 anat omy of these species was investigated to determine relative fibrosity. The majority of species preferred by elephants have strong and pliabl e barks, associated with a high proportion of fibres. However, not all preferred species have these characteristics, which indicates that fa ctors other than bark fracture properties affect species preference. B ark structure influences the way pieces of bark are stripped from a tr ee trunk during debarking. It is hoped that this paper will stimulate further studies on the effects of bark structure on the preferential f eeding behaviour of the African elephant.