At www.bbc.co.uk/news/science-environment-25865118 … winter gales in Wales have exposed the hidden remains of trees dating back 6000 years ago. However, on the TV a couple of locals popped up and pointed out some of the ruts near the trees were a relic from WWII – when amphibious landing craft with caterpillar tracks were being tested. Likewise, four squared off pits thought to go back thousands of years might also have a WWII origin. In addition, the coastline of Wales has changed in fairly recent times – have a look at Harlech Castle for starters. It is now inland but was built close to the sea. In addition, in the post Roman period large areas off the coast were submerged – and the memory of this survives in local folklore. So, it is not necessary to go back 6000 years for when the forest of trees flourished, although that might be the case. Presumably, scientists will be able to extract information from the trees themselves, the rings for example, or a C14 date.
The storms appear to have washed away a covering of peat – and the landing craft would have left their impression on the peat and on the clay or sand beneath the peat. There is a short video at the link above.