Wollemi pine
Discovered in 1994, in a remote gorge in Wollemi National Park, Wollemia nobilis is one of the world's most ancient and rarest trees, representing the only remaining member of a prehistoric genus, and is often described as a 'living fossil'.
David Noble, a National Parks Wildlife Officer, made the discovery whilst exploring remote gorges in the National Park. The Park covers 500,000 hectares and is the largest wilderness area in New South Wales; a rugged mountainous region of ridges, cliffs, canyons and undisturbed forest.
The Wollemia nobilis population comprises approximately 80 mature individuals and about 300 seedlings, found at three sites across the Park, and within 200 kilometres of Sydney.
Occurring naturally in deep, narrow sandstone gorges, Wollemia nobilis grows in warm temperate rainforests of Ceratopetalum apetalum, Doryphora sassafras and Acmena smithii, with an understorey comprising ferns such as Dicksonia antarctica, Cyathea australis and Blechnum nudum. The small population size, and very restricted distribution, means that Wollemia nobilis is potentially particularly susceptible to the effects of human activities or stochastic events. Specific threats include exotic pathogens such as Phytophthora cinnamonii, the introduction of invasive species, trampling and other forms of disturbance. Forest fires are a significant threat, as well as changes in rainfall and temperature patterns associated with climate change.
Wollemia nobilis produces two different types of foliage depending on the leaf's age and position on the tree. The largest Wollemi pine is 40 metres tall with a main trunk 1.2 metres wide. The tree's ability to develop multiple stems or being able to withstand temperatures ranging from -10 to 40 degrees Celsius, firmly identifies Wollemia nobilis as a remarkable tree, with vast potential that has yet to be truly explored.
The Wollemi pine is monoecious, and produces male and female cones on the same tree. The cones begin to be produced on the tips of separate branches when trees are more than ten years, although this varies much depending on growing conditions. The long male cones produce the pollen and the spherical female cones bear seeds.
Through millions of years of population decline, the Wollemi has maintained its ability to reproduce sexually, and has adopted a secondary reproductive strategy; self-coppicing. During winter months, it remains dormant and a white resinous coating forms over its growing buds, often referred to as a 'polar cap'. It is widely regarded that this adaptation may have helped the Wollemia survive many ice ages.
Further reading
Dettmann M and Clifford H 2005. Biogeography of Araucariaceae. In J Dargavel (ed) Araucarian forests. Australian Forest History Society Inc., pp. 1-10.
Farjon A 2008. A natural history of conifers. Timber Press.
Farjon A 2010. A handbook of the world's conifers. Brill.
Ben Jones