A prehistoric forest, an eerie landscape including the trunks of hundreds of oaks that died more than 4,500 years ago, has been revealed by the ferocious storms which stripped thousands of tons of sand from beaches in Cardigan Bay.

The forest of Borth once stretched for miles on boggy land between Borth and Ynyslas, before climate change and rising sea levels buried it under layers of peat, sand and saltwater.

Scientists have identified pine, alder, oak and birch among the stumps which are occasionally exposed in very stormy winters, such as in 2010, when a stretch of tree remains was revealed conveniently opposite the visitor centre.

The skeletal trees are said to have given rise to the local legend of a lost kingdom, Cantre'r Gwaelod, drowned beneath the waves. The trees stopped growing between 4,500 and 6,000 years ago, as the water level rose and a thick blanket of peat formed.

This year a great swath of the lost forest has been revealed. Last month archaeologists also found a timber walkway nearby, exposed by the storms. It was discovered by Ross Cook and Deanna Groom, from the Royal Commission on the Ancient and Historical Monuments of Wales, who went beach walking in the wake of the storms to check for any new finds. It was made from short lengths of coppiced branches, held in place with upright posts.

It has been dated to between 3,100 and 4,000 years old, built as the local people found ways to cope with living in an increasingly waterlogged environment.

Two years ago human and animal footprints were found preserved in the hardened top layer of peat, along with scatterings of burnt stones from ancient hearths.

A £13m coastal defence system to protect the modern village was opened in 2012, but as the recent exposure of the spectacular prehistoric landscape proves, the coast is still being scoured bare by storms and flood tides.