**3.2. Commercial value**

In addition to all the domestic uses of *V. karroo*, various commercial products are also obtained from the tree, of which gum is one of the most important (**Figure 6**). In fact, *V. karroo* gets its common name "sweet thorn" from this gum which comes out from wounds in the bark [6]. It is a pleasant tasting gum that is eaten by people and animals and has also been used for confectionary and adhesives [2, 16]. This gum is similar to gum arabic, which is widely used for thickening many convenience foods, pharmaceuticals and cosmetics [1].

The wood of *V. karroo* is hard and tough, making it suitable for making furniture, poles, and fence-posts [2]. It is also used to make wooden carvings (ornaments), which are very popular ornaments in the tourism industry [1]. The bark is used to make strong ropes and mats [2]. This bark and that of several other *Vachellia* species, notably *V. nilotica* (bark and pods)

**Figure 6.** *Vachellia karroo* tree exuding gum (photo: M. Dingaan).

contains tannin [1], which is widely used in the tanning of leather, giving it a reddish colour [5]. Tannins are plant polyphenolic compounds (secondary metabolites) that act as a defence mechanism in plants against pathogens and herbivores [49–51] and hostile environmental conditions [52, 53]. Most of the commercially extracted tannin in South Africa comes from Black Wattle (*Acacia mearnsii*), an introduced Australian species which can yield 36–44% tannin from the bark [1].
