Monday, 24 September 2012

The Unique Boab Trees of the Kimberley

Boab trees are one of the most famous icons of the Kimberley region in North Western Australia.  Their squat, bulbous trunks and spindly, often leafless branches lead them to being called the ‘upside down’ tree, as it looks as though it is the branches that are driving into the earth and the roots that are reaching up to the sky.  The Aboriginal legend concerning the boab tells that they were once destined to be the most beautiful tree ever created, with the tastiest fruit and the prettiest of flowers. But as the tree grew, its flowers were unattractive and the fruit tasted bad and gave off a bad smell.  The Tree God was very angry at this, so he pulled the boab out of the earth by its roots, and rammed it back into the soil upside down.

Boab Tree, Oscar Ranges, The Kimberley - Own Image
Boab Tree, The Kimberley

They are deciduous trees, losing their leaves in the dry season (March to October) and growing new leaves and large white flowers in the early part of the wet season.  Their binomial name is Adansonia gregorii and they are a member of the Malvaceae family.  The ‘gregorii’ part of the their name is to honour the Australian explorer Augustus Gregory, who undertook four major expeditions between 1846 and 1858 into the Australian interior, including one to try and find out what had become of the famous explorer Ludwig Leichhardt.   The Aboriginals have various names for the boab, including gadawon, larrgadiy and larrgadi.  They are also colloquially referred to as ‘bottle trees’, ‘gouty stem trees’, and ‘dead rat trees’. 

The Aboriginal people had uses for several parts of the boabtree.  Water was obtained from the tree’s hollows, the leaves had medicinal uses, the fruit was used to carve or paint on, and the white powder found in the seed pods was used for food.  Some parts of the tree, including the seeds, contain very high levels of vitamin C.  They are now grown commercially in the Kimberley as a food source, and it is the roots that are used.  They are harvested at between six to eight weeks of age when the root is roughly the same size and shape as a large carrot.  They are then sold in bundles like carrots and then after peeling can be sliced or grated.  Apparently they are crunchy and have a texture similar to a carrot or water chestnut.

They are very slow growing, eventually reaching a height of between 9 – 12 metres and developing a very squat, large trunk as they get older.  They can live to be many hundreds of years old, and it is estimated that some of the oldest are at least 1500 years old. The diameter of the trunk has been known to exceed five metres.  Some trees also appear to be split and it looks as if they have two trunks, which is caused by the young tree originally throwing out two shoots.  The trunks can also hollow out with age, and have been known to be used as dwellings or hiding places.

Boab Tree, Oscar Ranges, The Kimberley - Own Image
Boab Tree, The Kimberley

Boabs are the only species of Baobab that is endemic in Australia, and its range extends from the Kimberley into the eastern part of the Northern Territory.  Boabs that you see in other places in Australia have been transported there, such as the specimens that you can see in Broome and the boab in Kings Park in Perth.  All the other baobabs are endemic to the African continent, with six species coming from Madagascar and one from mainland Africa.  It is not known how the boab came grow in Australia, but it is believed that the seeds could have been washed over from Africa by the currents of the Indian Ocean, brought by sea birds or even early human visitors.  There is also a theory that they are a remnant species that has survived since Australia and Africa were both part of the ancient continent of Gondwana over 65 million years ago.

Boab Tree, Courthouse in Broome - Own Image
Boab Tree, Courthouse in Broome

There are several famous boab trees, and probably the most well known is the Boab Prison Tree, just south of Derby.  This is a large hollowed out tree that was used in the 1890’s as a lockup for Aboriginal prisoners, as they were being transported to gaol.  It is now a major tourist attraction and has been fenced off to deter vandalism.  The site has excellent information boards that tell the story of the Prison Tree and the Aboriginal prisoners, and of the natural history of the boab.

So while you are travelling through the Kimberley, look out for these beautiful and unique trees, and marvel at the natural icon that is the boab tree.