Native Trees of Australia
The boab or bottle tree is Australia's only representative of the Adansonia genus. Its full name is Adansonia gregorii. There are eight species of the genus with six indigenous to Madagascar, one to mainland Africa and one to Australia. Outside of Australia, the species are more commonly known as baobabs, monkey bread tree or upside-down tree.
Every boab is unique, oozing character and personality. There are many boabs in the Gregory National Park. From Kununurra through to Broome, boabs are common along the way.
The boab is endemic to the arid Kimberleys in northern Western Australia. The genus name comes from Michael Adanson, an 18th century French naturalist and explorer who first documented the African Baobab (Adonsonii digitata). The species name commemorates Augustus C Gregory, an English-born Australian explorer.
There is some conjecture as to how the boab made its way to Australia. The tree may have been present on Goondwana, 65 million years ago, before the great south continent split into its current configuration. Some believe the seed floated across from Africa to the west coast.
The boab is not a massively tall tree. The maximum height is usually in the range of 15 metres. The intriguing characteristic is the swollen trunk which stores water against the possibility of drought, an ever-present possibility in the north of Australia.
The trunk of the boab can reach a circumference of 20 metres.
While the boab is extremely slow growing, it can live for well over a thousand years. The boab is deciduous, losing its leaves in the dry season. The bark is very smooth and grey brown in colour. The leaves are compound having 5 to 9 elongated leaflets. The tips are pointed. The new leaves of the boab are always in place and thriving well before the first downpour of the 'wet'. The tree seems to know when to expect the break of the season.
The flowers are fragrant and intricate. Large and white, they appear in the wet season any time from October on. Around January, the woody, dark brown nuts appear. These can be a variety of shapes and sizes and are covered with fine, light olive to brown hairs. Inside the nut are many kidney-shaped seeds which sit in a white pith. The large, oval nuts are popular with craftspeople. The dark surface can be carved and shaved, revealing a paler inner layer.
The Adansonia is very high in Vitamin C having a higher content than the orange. The African species is exceptionally high in the vitamin but there have been few studies done on the Australian species.
The edible parts of the boab are being promoted as gourmet food items. Seeds, leaves and roots are being harvested on commercial plantations in the Kimberley. The indigenous aborigine has long known of the benefits of the boab as a source of food and medicine. A paste or flour was made by grinding the seeds. The leaves were used for medicinal remedies. The roots had a texture akin to water chestnuts and were keenly sought. Young leaves can be used in salads. And, in times of drought especially, water could be obtained from the trunk.
Back in the 1890s, several boabs were used as temporary prison cells. One is still standing and is a popular tourist destination. It stands just 7km from Derby just past the Gibb River Road turn off. The trunk was hollow and had a circumference of over 14 metres. The door is a metre wide and two metres high. Aboriginal prisoners would be placed in the 'cell' overnight before being taken on to Derby.
Twenty-three kilometres from Wyndham at the eastern end of the Kimberleys is another boab which was also used as a cell. The circumference again is just over 14 metres and the tree is believed to be at least 1500 years old. Boabs do not have growth rings like most tree varieties. This particular boab is of significant cultural importance to the local aboriginals and is not accessible to the public.
A boab named Gija Jumulu was transported over 3,200km from Warmun in the Kimberleys to Kings Park in Western Australia's capital, Perth. This iconic tree is believed to be 750 years old. The indigenous Gija people performed a farewell ceremony to the tree on Monday, 14 July 2008. 'Jumulu' is Gija for 'boab'. The tree was hampering roadworks on the Great Northern Highway so was transported by road to Perth. The tree weighed 36 tonnes and has a diameter of 2.5 metres. There was much concern that such a large mature tree should be transported so far from its birthplace.
A smoking ceremony was held by local Nyoongar people to welcome the tree to its new home and over 3,000 people attended the ceremony. Despite the size of the tree, Gija Jumulu is looking healthy and delighted thousands by flowering last year.