Indigenous knowledge and science: The case of Heteropyxis natalensis as a lightning tree
In South Africa, indigenous beliefs and practices relating to protection against lightning have been passed from generation to generation. In the southern part of Mpumalanga Province, which falls within the extreme risk category for lightning in South Africa, one such belief involving a specific species of tree, Heteropyxis natalensis, was used by indigenous Tsonga/Shangaan people to guide their choice of a building site for their homesteads. They believed the trees attracted lightning, and because thatch was used as a roofing material, lightning posed a great risk which could cause the buildings to burn down. Consequently the location of these trees was taken into account and they were carefully avoided. Such indigenous knowledge, born out of intimate knowledge of the environment, can occasionally be explained by science. In this case, processes which operate at a molecular level indicate that the aromatic properties of these trees, in association with the local climatic and geologic setting, create a specific set of conditions that could lead to the trees presenting as a target for lightning.
Keywords: Lightning, indigenous knowledge, lightning trees, Heteropyxis natalensis, radon, granite, aromatic oils.