Alert – Tree trunks, stumps and roots from ancient submerged forest that’s at least 4,000-years-old are uncovered on Cornish beach after lowest tide of the year – News Alerts

A low tide on a Cornish beach has revealed the trunks, stumps and roots of an ancient forest that’s at least 4,000 years old.

Winter storms shifted sands in Mount’s Bay, meaning when the sea withdrew further than usual this week, it revealed the remnants of prehistoric trees.

The forest in Mount’s Bay has been known for centuries with St Michael’s Mount’s original name in Cornish being ‘Karrek Loos yn Koos’, meaning ‘Grey Rock in the Wood’.

But the peat beds that contain the remnants of the forest floor are only revealed every so often.

Tree trunks, stumps and roots from an ancient submerged forest in Mount’s Bay thought to be 4,000 to 6,000 years old

The ancient woodland was revealed following the lowest tide of the year

In January 2023, there were storms on the south coast which showed signs of the woodland and in March 2021 the ancient forest could be seen during the biggest tide of the year.

The last time a significant number of tree stumps and roots were uncovered at Chyandour Beach in Mount’s Bay, next to Penzance, was following the Valentine’s Day storm in 2014.

March 12 saw the lowest tide for this year when sea levels dropped to just 0.22 metres at Newlyn.

The Environment Agency issued flood warnings the same day, covering most of the coast of Cornwall.

The woodland is believed to also contain alder and hazel trees

The woodland is believed to also contain alder and hazel trees, and would once have existed far offshore when farming communities began to take shape across the UK.

It was claimed in 2014 that the forests show evidence of the changes Mount’s Bay has undergone as sea levels have risen since the end of the last glaciation.

Geologists have concluded that extensive forests extended across Mount’s Bay between 4,000 and 6,000 years ago.

According to Cornwall Geoconservation Group, there are a number of similar submerged forests around Cornwall that are occasionally revealed from under the sand.

These include beaches at Bude, Daymer Bay, Portreath and Pendower.

What are the ‘Submerged Forests’?

The Submerged Forests refer to a group of palaeosols (a layer of rocks in the ground formed as a soil in a past geological age) found beneath present-day offshore sediments.

The forests along the Cornish coastline have been remarked upon for centuries, but there is relatively little known about them.

They were first described in the mid-sixteenth century by English poet, John Leland.

During spring low tides, people are able to see the often sizeable and well-preserved remains of trees.

Similar tree remains have been reported even further out to sea at a great depth at places such as Porthluny.

But the most extensive deposits are known to occur with Mount’s Bay.

The Submerged Forests are developed on the Devensian (the last glacial period in Britain) land surface such as the head deposits at Prah Sands or on Holocene alluvium (a type of sand) such as in parts of Mount’s Bay.

Dating Submerged Forests have long proven problematic but they are estimated to be at least 4,000 years old.