Sunday, September 12, 2004


Sunken forest found after 6500 years


VICKY COLLINS, Environment Correspondent

IT has all the ingredients of an Indiana Jones adventure: an academic, an old map, and a search for hidden treasure older than the pyramids of Egypt.

This treasure, however, is a forest in Orkney, which was buried beneath rising sea levels 6500 years ago. Alistair Rennie discovered it while doing a PhD looking at the effect of rising sea levels in the area, which he hopes will inform methods of dealing with climate change.

His studies, funded jointly by Scottish Natural Heritage and Glasgow University's geography department, took Mr Rennie and his colleagues to Sanday, Orkney, which he described as a "sinking island".The 27-year-old said: "We looked at a series of beaches there and we came across poems and letters and legends suggesting there was this submerged forest on the other side of the island at Otterswick Bay.

"A man called Dr Triall had written about a woman who walked down to the bay after a storm in 1838. The sand on the beach had been all whipped up and she saw a huge expanse of what looked like black moss where there should only have been more sand. "We also came across an old map. It was produced in 1847 by a Commander Becker and the submerged forest was marked on it. "He had not seen it himself – it referred to what someone had said they had seen before.

It wasn't quite X marks the spot, but it gave us a good idea of where to look." Mr Rennie then went out in search of the forest and, after researching any possible environmental impacts, decided to use a JCB to dig into the sand on the bay during low tide. "The first five holes were unsuccessful and I was beginning to think the forest wasn't there. But then in the sixth hole we came across it." In fact, it was actually a layer of peat containing parts of trees, the biggest about the size of a man's thigh. After digging a few more holes, Mr Rennie and his team were able to collect 12 samples of trees which they took back to Glasgow for identification.

He said: "It turned out the trees were salix, which is a willow tree, although they weren't able to identify the type of willow. It looks like these trees would have been quite substantial, about 9ft tall." The samples were then taken to the Scottish Universities Environmental Research Centre in East Kilbride, where carbon dating revealed that the trees were 6500 years old.

As well as the excitement of the discovery, Mr Rennie said the forest had helped him conclude that sea levels had risen by three metres since the trees were alive in 4496BC. "This is a lot, but over that period of time it is not that worrying," Mr Rennie said.

Mr Rennie, who has now almost completed his PhD, will present his findings at the Orkney Science Festival today.

See article here.

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