A biological fortress
The Australian boab (Adansonia gregorii) is a biological oddity, one of only a few baobab species found outside of Africa and Madagascar. It is endemic to the Kimberley region of Western Australia and the Northern Territory. These trees are defined by their massive, bottle-shaped trunks which can store over 100,000 liters of water to survive the long dry season. As a deciduous tree, it loses its leaves during this dry period, producing new foliage and large, white flowers between December and May. The flowers open at night and are often pollinated by the convolvulus hawk-moth.
The specific tree near Derby has a trunk circumference of over 14 meters. Radiocarbon dating suggests it is approximately 1,250 years old. A common characteristic of older boabs is the hollowing of their trunks, which occurs when the soft, spongy inner tissue dies off. Before European colonization, this particular tree was a culturally significant site for local Aboriginal people, including the Nyikina and Warrwa. In 1916, anthropologist Herbert Basedow noted it was used as a shelter and as an ossuary — a place to store the bones of the dead.
A contested history
The narrative that the Derby boab was used as a temporary prison for Aboriginal people being marched to the town for sentencing emerged in the late 19th and early 20th centuries. While this story is supported by longstanding oral traditions from both Aboriginal and non-Aboriginal sources, concrete documentary evidence from the colonial period is absent. Some historians argue the story is a myth that began around 1948, when the history of another boab tree in Wyndham was mistakenly attributed to the Derby tree.
Despite the historical debate, the tree is officially protected under the WA State Heritage Register and is a registered Aboriginal Site. It is a symbol of the colonial-era treatment of Indigenous people. For many, the lack of definitive proof does not diminish its importance as a site of memory and a way to understand a difficult chapter in Australian history. Interpretive signs at the location now present information on its natural environment, its role in the pastoral industry, and its deep Aboriginal heritage.