It’s not all about the ‘big and hairies’ when in the bush. Gordon Homer, Peace Parks’ Project Manager for Kavango Zambezi Transfrontier Conservation Area, teaches a visiting team from Peace Parks head office in Stellenbosch a thing or two about a rather a thorny subject…the Knob-thorn tree.
The team are visiting Simalaha Community Conservancy in Zambia when they come across a large, shady tree that tempts them with precious refuge from the hot, African sun. This is the Senegalia nigrescens, more commonly known as the Knob-thorn tree. The chances are quite high that you might have seen a Knob-thorn or two before, as they are commonly found anywhere north of KwaZulu-Natal in South Africa, all the way up to Tanzania.
Previously known as the Acacia nigrescens, the name was derived from the Greek work ‘akis’ which means spike or knob, and the Latin word ‘nigrescens’ which means ‘becoming black’. This is thought to be referring to the pods that turn black in colour when ripe. The Knob-thorn is a slow-growing, deciduous tree that can survive in many different soil types, equipped with small, sharp thorns that can make life a little unpleasant if you happen to brush up against them.
These thorns, however, do not dissuade the animals that feed off this highly nutritious tree and instead only limit the number of times that they munch on it before moving on to the next. This tree is a feast for many; monkeys and baboons delight in eating the flowers and the pods, while the elephants eat the bark, which unfortunately often leads to the tree’s demise. Browsers such as giraffe and kudu also eat the leaves.
Gordon, Peace Park’s very own bush expert, explains that giraffe are believed to be primarily responsible for the tree’s pollination. As they feed off the leaves, the pollen sticks onto their horns, or ossicles, and when they move on to eat from another Knob-thorn, pollination takes place.
Apart from keeping the animal population happy and healthy, the Knob-thorn also has many traditional uses. Some of these include helping to soothe stings from bees, wasps, or scorpions, as well as using the powder, ground up from the knobs, as a painkiller. The hard, heavy wood was also used as railway sleepers and fence posts in the past.
We are thankful for Gordon’s vast knowledge of his environment, helping us learn about the magical African bush and the role that everything and everyone has in the ecosystem.