Parts of Australia became a stark and inhospitable landscape, lakes dry up. forests disappeared, desert expanded and many animals became extinct . Sea levels also fell some 100m allowing connections between mainland Australia, Tasmania and New Guinea.
The ice age threatened the very survival of Aboriginal people who had arrived some 30,000 years earlier, It has been suggested that up to 60% of the entire population may have perished during this ice age."
Over a 105 million -year period the super continent of Gondwana broke up forming the land masses of Africa, Madagascar, South America, India, Antarctica, New Zealand, New Guinea, New Caledonia and Australia. Fossilized pollen records show that Nothofagus were growing on all these masses except Africa, Madagascar and India. Today the 35 species of Nothofagus are found only in the Southern Hemisphere.
About 10 million years ago Australia's climate began to dry, and over time, the rainforests retreated to isolated areas of high rainfall and altitude on the east coast. The Tweed Caldera is one area where Nothofagus took refuge.
Although normally regenerating from seeds, this northern population of trees continues to survive mainly through the dying and regrowing of new stems from the tree's base and suckering form the roots ".