The Kruger National Park has an incredible variety of species, whether it be plants, birds, mammals, insects, reptiles or even fish. And spending enough time within the park will allow any visitor to see many of these species. Some species however, just stand out in their own unique way and that is how the Big 5 trees of Kruger Park were decided on.
At this stage, 404 tree species have been identified in the Kruger National Park. For now, however, we will only be discussing five of these. They are the Baobab (Adansonia digitata), Fever Tree (Vachellia xanthophloea), Knob-thorn (Senegalia nigrescens), Marula (Sclerocarya birrea) and the Mopane (Colophospermum mopane).
The Baobab is arguably the most iconic of the Big 5 trees listed above and most people are simply amazed at their size and how long they live. The Baobab is part of the genus (Adansonia) of which there are 9 species in the world.
Madagascar has an incredible 6 species, one species occurs across the Middle East and parts of Asia, one in Australia, and then the one found on mainland Africa. Adansonia digitata is the species we find in Africa and within the Kruger National Park. Out of the 9 species A. digitata grows to become the largest and also lives the longest.
Within the Kruger Park this species is most commonly found north of the Olifants River where it prefers deep, well-drained soils found in rocky areas and in alluvial plains, but fortunately for those that are not likely to go that far north there is one magnificent specimen which can be found just off the H1-3, which is the main road running north/south between Satara and the Tshokwane Picnic Site. There is a sign close to the Kumana dam indicating the turn-off to the tree.
While the Baobab tree does not necessarily grow very tall, what it may lack in height it makes up for in the girth of its trunk. The sheer size of the tree makes it unmistakeable. The huge trunk often has hollows which may be deep enough for a human to hide in.
Trees with a trunk circumference of 30 metres and more can be found and it is generally estimated that these trees are about 4,000 years old making them of the oldest living trees in the world.
Up to 76% of the tree consists of water or moisture, which is well-controlled by the tree and not something a human can just tap into. The girth of the trunk swells during the rain season and decreases again during the dry season.
Few trees offer humans and animals as much as the Baobab does. Hollow branches catch rainwater and act as a reservoir that can be used by humans and animals, especially in times of drought. In some areas people are also known to cut hollows into the trunk which then allows for extra rainwater to collect in the tree.
In drier parts, elephants are known to cause a lot of damage to the trees by carving and stripping big pieces of bark off the trunk to get to the moisture. At times, this damage may become so extensive that the tree can no longer be supported by the trunk and collapses.
In an effort to save these old trees, a circle of sharp rocks will be packed around the base of the trunk so that elephants can no-longer reach the trunk. Their feet being too sensitive to step on the sharp rocks. Fortunately, the Baobab tree is one of a few trees that can still survive after having been ring barked.
The inner bark which is made up of the phloem and which is usually responsible for the transporting of nutrients from the roots to the shoots and vice versa is quickly regenerated after being destroyed and the continual movement of nutrients is then secured.
The bark and leaves have also been used for treating malaria and dysentery. In West Africa, the bark and leaves are claimed to have anti-inflammatory and diaphoretic properties and are regarded as a remedy for urinary disorders and mild diarrhoea.
Fresh leaves are prepared and eaten as a type of spinach. Flour is made from the roots. The fruit is edible and has a creamy flesh which can be sucked from the pips. The pulp is rich in Vitamin C and when mixed with water can make a refreshing drink. The Afrikaans name for the Baobab tree ‘Kremetart’ which directly translates to ‘cream of tartar’ may suggest that the pulp has also been used as a substitute for cream of tartar.
The large white flowers are only found on the tree for a short period during the months of October and November and are then replaced by the woody fruit that can be seen hanging from the branches between January and May.
From June to October, the tree is bare or may begin to just show some leaves. During this time, the tree has a very distinct look, as though the branches are its roots. This look has led to the San referring to it as the ‘upside down tree’ and believing the trees fell from the heavens.
The next tree we will discuss, and one you should definitely look out for on your next safari, is the Fever tree (Vachellia xanthophloea) which, until recently, was still called an Acacia, the genus then being reserved for Australian trees while the African ‘Acacia’ trees mostly changed to the genus ‘Vachellia’.
Similar to the Baobab, the Fever tree is an iconic tree and easily recognisable by its all yellow to lime green bark. It, however, looks nothing like a Baobab tree.
The Fever tree is a species that typically only grows near permanent water, such as rivers, swamps and pans. In some areas they grow together in big numbers forming what is referred to as Fever tree forests. An example of this can be found in the very northern Kruger Park and can be seen while on an overnight trail in the area.
As mentioned before, Fever trees are quite distinctive with their bright yellow/green barks. The bark is coated with a yellow powder and peels off in thin layers. The tree itself grows up to about 25m in height and because it has small compound leaves, the canopy appears open and sparse. Its branches are covered in long white thorns typical of many of the trees in the Vachellia genus.
Small, round pom pom-like flowers occur on the tree during springtime and may be seen on the trees up until November. Green bean-like pods hang in clusters and turn brown in late summer when they are ripe.
Monkeys and baboons will feed on the flowers, young shoots and leaves, while antelope like the impala may be seen feeding on the fallen flowers as well as the pods. Elephants and giraffes will also browse on the leaves, pods and branches. Due to its proximity to permanent water, and the presence of thorns, this tree is often used by weavers to build their nests.
The name Fever tree is derived from the early settlers who believed the tree was responsible for Malaria. The fact that these trees like wet areas which is typically where mosquitoes are found only cemented this idea further. It was believed that when the wind blew the fine powder off the bark and it was then breathed in, a person was likely to get malaria.
It was only years later that it was discovered that the real reason for the malaria fever was in fact a mosquito and not the Fever tree. The name however has remained the same.
Now if you were wondering about the bark and its colour, then here is the answer and it's really interesting. The leaves on trees contain chlorophyll which is the pigment that gives leaves its green colour. It is through the leaves that photosynthesis occurs. Fever trees are quite unique in that the bark contains chlorophyll and photosynthesis can therefore take place through both the leaves as well as the bark.
Fever trees are fast growing and can grow at around 1.5m per year. With this in mind and because of it being an attractive and fairly hardy tree, it is often planted along streets in suburbs as well as in parking lots for extra shade cover.
The Knob-thorn, previously and more commonly referred to as the Knob-thorn Acacia, also had to undergo a bit of a name change as the genus Acacia was no-longer allowed.
For this specific species, the genus changed from Acacia to Senegalia. Acacia referred to ‘thorny’, which this tree certainly is and the species name ‘nigrescens’ means ‘turning black’. This is believed to refer to the actual thorns that darken and may also refer to the darkening pods.
The Knob-thorn is a very upright thorn-tree, with a straight, single trunk that branches high up. The trees can grow to heights of around 15m. The canopy is fairly sparse due to the smaller compound leaf structure, however the leaves are larger than most other species from the previous Acacia genus.
As the name suggests, these trees have knobs with thorns growing from the knobs. This is particularly evident on young trees and on the large, young branches of older trees. Spikes of white flowers cover the leafless trees in spring (August to September). It is the only tree to have masses of white flower spikes and no leaves.
Knob-thorns prefer clay soils such as those found on basalts and in the valleys of granite landscapes. In the Kruger, it is less common north of the Olifants River and does not grow in riverbeds or directly along permanent water. The tree is drought resistant as well as being termite resistant because of its hard wood.
This tree is very vulnerable to animal damage. It is often attacked and may even be killed by woodborers. Elephants easily ringbark and push over these trees.
Elephants feed on the bark which is believed to have healing properties and aids them in fighting tooth decay. The tree seldom regrows after being pushed over or otherwise damaged by elephants. The flowers are eaten by monkeys, baboons and giraffes.
The leaves and shoots are browsed on by kudus, elephants and giraffes. Giraffes also eat the pods and it is believed they also assist in the pollination of Knob-thorns. The Knob-thorn is one of the first trees to flower during springtime in Kruger Park and with giraffes having the necessary height advantage, they can reach high up to browse the tree and thereby rub their neck on the flowers unintentionally collecting pollen, which is then distributed from tree to tree as they browse.
Holes in the tree trunk and branches offer good nesting sites for birds, while White-backed Vultures are known to nest on top of these trees.
Humans use these trees for fence posts as well as for walking sticks and knobkieries (fighting sticks). Poles in rural villages may be planted in the ground to act as lightning conductors. The bark has high tannins levels and is thus used for the tanning of leather.
The knobs are sometimes ground into a powder and used by villagers as a painkiller and to help with eye-infections. Some tribes also believe that by applying the powder, a woman will be able to grow large breasts. Parts of the inner bark can be used to make a strong twine.
Other popular uses include flooring - the beautiful hard wood of the Knob-thorn is perfect for floors and has the durability necessary to make it a popular choice for people wanting wooden flooring.
This is one of the well-known tree species found throughout Kruger Park. The scientific name Sclerocarya birrea is derived from the words ‘skleros’ which is a Greek word meaning ‘hard’ and ‘karyon’ meaning ‘nut’. This refers to the hard pit found inside the fruit of the Marula. The species name ‘birrea’ originates from the common name ‘birr’ for this type of tree in Senegal.
The Marula tree belongs to the family Anacardiaceae which is the same family that the mango, cashew and pistachio belong to.
Marula trees are a single-trunked, high branching tree with a characteristic semi-circular canopy. The bark often peels in conspicuous, characteristic, rounded depressions, exposing the smooth pink brown undersurface. This gives the trunk a spotted appearance and helps to more easily identify the tree.
Caution should be taken however as the False Marula – Lannea schweinfurthii has a very similar looking bark but typically darker, smoother and shinier than that of S. birrea. The leaves hang from the end of thickened twigs that stand out almost like fingers in winter.
Marula trees have several links with animals. Mosquitoes often breed in the hollows of the tree where water collects. The larvae of eight species of butterfly feed on the foliage.
The fruit which is what the tree is probably best known for is eaten by a wide variety of animals such as elephants, monkey, baboon, kudu, duiker, impala and zebra, while the bark and foliage is also eaten by elephants.
There are also several uses by humans, and this includes the roots being tapped during times of drought due to the large quantities of water held in them. The fruit is very tasty and rich in Vitamin C and is used to make beer, jelly and jam.
The seed kernels are rich in oil and protein. Analyses show the marula kernel has up to 3,100 kJ per 100gm, with a high protein and fat content.
Medicinally in South Africa, diarrhoea, dysentery and unspecified stomach problems are treated with the bark, which is believed to be of value in combating fever and in the treatment of malaria. Chewing the fresh leaves and swallowing the astringent juice will help with indigestion.
In other parts of Africa, the main medicinal use is in the treatment of diabetes. Furthermore, the tree plays an important role in marriage rituals and has an integral role in fertility rites. It is known to the Zulu people as the ‘marriage tree’, being a symbol of fertility and is used in a cleansing ritual before marriage.
The Marula tree is dioecious meaning it has separate male and female trees and it is not by coincidence that the female Marula tree is one of the most prolific fruit bearing trees in Africa. Another belief by the Venda tribe is that by taking an infusion of the bark of the tree, the sex of an unborn baby can be determined. So an infusion of the bark from a female tree if a daughter is wished for and an infusion of the bark from a male tree if a boy is wished for. If a child of the opposite sex is born, then the child is said to be very special in being able to defy the spirits.
The fruit can be found on and around the base of the tree from late December through to February. The fruit drops from the trees while still green and then ripens on the ground. During this time, it’s not uncommon to see elephants spending a lot of time under the trees seemingly gorging themselves on the fallen fruit.
In an effort to reach the fruit that are higher up, elephants may lean up against the trunk and give the tree a good shake so that the fruit can drop to the ground and then be eaten. There is a myth that elephants can become drunk from eating the fermenting fruit. This story comes from a nature documentary made in 1974 called ‘Beautiful People’ depicting these animals becoming drunk after eating the fruit.
This, however, has since scientifically been proven to not be possible. The sheer size of an elephant and the amount of fermented fruit it would have to eat at one time with various other permeations for it to get in enough alcohol to become intoxicated, is simply not possible.
The last of the Big 5 trees to look out for on your next Kruger safari is the Mopane tree, also sometimes written Mophane or Mopani. The common name is also the Shona word for a butterfly because of the distinctive butterfly shaped leaves. The scientific name Colophospermum is a Greek word meaning ‘oily seed’.
In this case, they are referred to as pods and are flattened, oval, leathery and kidney-shaped and covered with many glands that exude a sticky substance which is not as useful as other parts of the tree.
Mopane trees grow at different lengths depending on the soil and external factors, such as elephant damage causing stunted growth, for example. It is a tree that prefers clay soils. Where soils are shallow or poorly drained, the growth may also be stunted.
Trees growing in deeper soils and near watercourses can grow to a substantial height. Where Mopane trees grow, they are often the dominant tree in the area. It is not a tree commonly found south of the Olifants River in Kruger Park, but north of the Olifants, it is prolific and covers vast areas, as far as the eye can see with few other shrubs or trees between them.
The trees have a single, straight trunk, while shrubs are multi-stemmed with a V-form. The leaves are butterfly-like in their shape and quite characteristic. It is a tree which prefers warm weather and is frost sensitive.
Links with animals include the leaves being eaten by elephants and buffalo, although these are not very palatable. During times of drought, the fallen leaves will be eaten by almost all animals. The leaves sometimes become infected by aphids which are fed on by baboons. The wood is hard but where holes occur, these are used as nesting sites for birds and small mammals, especially the Tree Squirrel or Smiths Bush Squirrel, as it is also referred to.
The larvae of the moth Gonimbrasia belina feed extensively on the leaves and are known as ‘mopane worms’. These worms are collected and eaten by many people as a valuable source of protein.
Other human uses include using the hard, durable wood for furniture, railway sleepers, fence posts, flooring and even to make flutes. The wood also makes excellent coals to cook on. A sap from the bark is used to treat venereal diseases. Tannins in the bark are used for the tanning of leather. Leaves of the Mopane have also been known to assist in stopping bleeding, and to accelerate the healing of wounds. Twigs are chewed on and these frayed ends are then used as a toothbrush.
And those are the top five trees to look out for on your next Kruger National Park safari. Enjoy!
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