Recent storms have again uncovered the hidden remains of an ancient woodland said to be between 4,000-6,000 years old on the beach at Portreath in Cornwall. Heavy storms cause the sands to shift, a phenomenon that only occurs once every few years, exposing the trunks of the trees. Waterlogged wood tends not to rot as it has no oxygen. The wood had previously been visible after storms in 2014 and 2016. It takes a few days for the waves to push the sands back to normal and the trunks to vanish for another few years.