Unexpected discovery of an ancient forest 15-30 million years old buried 6m underground

The ancient forest was discovered nearly 6m underground in a place where for tens of thousands of years there were no large trees, only shrubs and other low vegetation.

British archaeologists have announced the discovery of an ancient forest dating back 15 to 30 million years in the Falkland Islands , an overseas territory in the South Atlantic also claimed by Argentina and called the Malvinas, where for tens of thousands of years there were no large trees but only shrubs and other low vegetation.

A panoramic view of the Falkland Islands shows the windswept, treeless landscape - (Photo: Zoë Thomas/University of Southampton).

The forest was discovered nearly 6m underground , when tree trunks were dug up from peat at a construction site near the capital Stanley.

Dr Zoë Thomas, a lecturer in geophysics at the University of Southampton (UK), lead author of the study on Falkland/Malvinas, said the discovery was very strange because what people know about the archipelago is a very windy and barren place, with no trees growing.

Ms. Thomas and her colleagues went to the site and began collecting the large logs. She said the remains of the tree were so pristinely preserved that they looked like driftwood.

The trunks of Sanfordiacaulis densifolia are covered in more than 250 spirally arranged leaves. This unique preservation is the result of earthquakes in a 352-million-year-old lake system now in New Brunswick, Canada.

The logs and peat samples were transported to a laboratory at the University of New South Wales in Australia for study. Scientists used electron microscopes to reconstruct highly detailed images of the wood's cellular structure.

The log is 15-30 million years old and in perfect condition - (Photo: Zoë Thomas/University of Southampton).

According to Dr Thomas, the presence of tree fossils suggests that the island once hosted a temperate rainforest, a completely different ecosystem from the island's current environment. The story of this forest goes back even further than researchers initially thought.

The tree was too old to be radiocarbon dated, a method that can determine the age of organic matter up to 50,000 years old. The international team of scientists turned to microscopic pollen grains and spores found in peat for answers.

Pollen records have led to the conclusion that the tree trunks and branches are between 15 and 30 million years old. This suggests that the climate in the Falkland/Malvinas Islands was wetter and warmer than it is today millions of years ago.

Michael Donovan, director of the paleobotany collection at the Field Museum in Chicago, said the Falkland Islands/Malvinas are now all grasslands and lack native trees. The fossil pollen, spores and wood in the study paint a very different picture of the ancient environment, providing direct evidence of the presence of cool, wet forests.

Important site for climate change research

The exact reason why the trees are no longer growing on the Falkland/Malvinas Islands is unclear, as they thrive at similar latitudes in South America, according to the study. Both experts believe that the strong winds and acidic peatland environments there may be to blame. These characteristics also make the Falkland/Malvinas Islands an important site for studying climate change in the Southern Hemisphere.

Thomas added that prevailing westerly winds can influence Antarctic ice, atmospheric circulation and rainfall patterns, and the islands are one of the few land masses in their path. Understanding how these winds have strengthened or weakened in the past, given the islands' proximity to Antarctica, could help predict future changes in climate.

However, the islands are unlikely to return to forested landscapes any time soon, according to Ms Thomas. "Current projections suggest the region will be warmer but also drier, leading to concerns about the risk of peatland erosion," she said .