Remains of ‘spectacular’ ancient polar forest discovered on Tasmania’s West Coast

A researcher has made a remarkable discovery near Macquarie Harbour, unearthing the remnants of an ancient polar forest and shedding light on the ecology of the Gondwana supercontinent.

Dr Miriam Slodownik at the Lowana outcrop. New remains of a 53-million-year-old polar forest have been unearthed near Macquarie Harbour in Western Tasmania, unveiling previously unknown ancestral origins of rainforest plants in the southern polar region. Picture: Greg Jordan

The remnants of a 53 million-year-old polar forest have been discovered on Tasmania’s West Coast, offering a remarkable deep time glimpse into the ecology of the ancient Gondwana supercontinent.

University of Adelaide PhD graduate, Dr Miriam Slodownik, unearthed the forest’s remains near Macquarie Harbour and has published her research in the American Journal of Botany.

The staggering find has revealed crucial details about the ancestral origins of rainforest plants found in the southern polar region and the evolution of southern rainforest in the early Eocene epoch about 50 million years ago – the last period of extreme greenhouse conditions.

“This discovery offers rare insights into a time when global temperatures were much higher than today,” Dr Slodownik said.

“Tasmania was much closer to the South Pole, but the warm global climate allowed lush forests to thrive in these regions.”

A diverse range of plant life was found on the fruitful expedition, including two new species of conifer known as Podocarpus paralungatikensis and Araucaria timkarikensis (named in the reconstructed Tasmanian Aboriginal language of palawa kani).

Plant matter reconstructions by Dr Miriam Slodownik. New remains of a 53-million-year-old polar forest have been unearthed near Macquarie Harbour in western Tasmania, unveiling previously unknown ancestral origins of rainforest plants in the southern polar region. Picture: Supplied

Also uncovered were a variety of fern and tree species. Dr Slodownik said many of these were ancestors of flora found in regions including New Zealand, Indonesia, and South America.

“The most spectacular fossils are relatives of the Kauri, Bunja and Wollemi pines that give clues about the evolution of these iconic Australian trees,” Dr Slodownik said.

About 400 new plant fossils were excavated and prepared in the Palaeobotany Laboratory at the University of Adelaide.

With techniques including ultraviolet photography and microscopic analysis, researchers have shed light on minute details of leaf and cellular structures, revealing much about the relationship between the ancient plants and their modern counterparts.

“These fossils highlight the historical connections between Antarctica, South America, and Australia, which were once part of the ancient supercontinent Gondwana,” Dr Slodownik said.

“The analyses showed how these plants adapted and thrived across the Southern Hemisphere in warm, ice-free conditions, even with the extreme seasonal changes near the polar circle.”

Dr Slodownik said the polar regions of the earth became covered in glaciers as the planet cooled, causing the landmass we now know as Australia to drift northward and carry the polar plants in the direction of the equator, where they evolved into the species that we see today.

“This study revealed the amazing diversity of Tasmania’s fossilised forest. These plants tell the story of big changes in climate and the shifting tectonic plates over millions of years,” she said.