To determine the age of the Wollemi Pine trees, a scientific team cut cross-sections from one of the fallen trunks (a large mature, 35-40 metre trunk) at the original site in Wollemi National Park, and sent them to the Australian National University Forestry Department for analysis.
One of the most intriguing things that can’t be determined, due to coppicing (the unusual branching habit which leads to old Wollemi Pines having many separate trunks), is how old the original tree was before this particular trunk was produced. It may have been hundreds, or perhaps thousands of years since it was a seedling!
By counting the growth rings from cross-sections of the trunk and combining this with carbon dating, the best estimate for this sample trunk is about 350 years old. This means that this trunk started growing around 1650! See also 'Determining its age' and 'If Trees Could Talk...'.
The Wollemi Pine belongs to the conifer family Araucariaceae, and its closest living relatives in this family include the Kauri (Agathis species), Norfolk Island, Hoop, Bunya Bunya and Monkey Puzzle pines (Araucaria species). Morphological, wood anatomy and DNA analysis suggest that the Wollemi Pine is a new genus, falling between the two previously known living genera: Agathis and Araucaria.
Conifers date back to the Carboniferous age, more than 300 million years ago. ‘Modern’ (evolved) conifers, like the Araucariaceae family, are known from the Triassic period, more than 250 million years ago.
There are Triassic fossil examples of the Araucariaceae family, which reached maximum diversity during the Jurassic and Cretaceous periods, between 200 and 65 million years ago, with worldwide distribution. At the end of the Cretaceous, when dinosaurs became extinct, so too did the Araucariaceae in the northern hemisphere.
Until about the middle of the Tertiary (30 million years ago), plants in the Araucariaceae grew in the forests of the southern super-continent of Gondwana (which included Australia, Africa, South America, Antarctica and India). The Araucariaceae family then began a slow decline in range and diversity as flowering plants, better adapted to climate change, began to evolve and gradually displace conifers. The last fossil record of the Wollemi Pine is dated at about two million years ago and so the Pine was thought to be extinct. See also 'Tracking through time'.