During the late Carboniferous period around 310 million years ago, the Scottish Lowlands were covered in dense tropical rainforest. The forests, akin to those in Brazil today, flourished as Scotland rested at the Equator on its long journey north. The fossil trees dating from this time have added a great deal both to our geological and ecological understanding of the Carboniferous, as well as the mineral wealth of Scotland – the lush forests became the vast coalfields under the central belt which have been extensively mined over the last century. Perhaps the most famous fossil trees are those in the Fossil Grove in Victoria Park, Glasgow. The eleven tree stumps, preserved in immaculate detail, are of club-mosses or Lepidodendron, which could grow to up to 30 metres in height. Their heavily-patterned bark can still be seen, along with their root structures. Scotland led the way in making Fossil Grove the world’s first geological conservation site.
Other important Scottish fossil trees include trunks of 330-million-year-old swampland trees from Craigleith Quarry in Edinburgh, which now takes pride of place outside the Natural History Museum in London and the Royal Botanic Garden in Edinburgh. Similarly aged small groves of fossil tree stumps also occur at Saltcoats Harbour, on the Ayrshire coast.
More recently in geological history, the volcano on the Isle of Mull preserved many more recognisable species when it erupted – fossilised remains of oak, hazel, and magnolia can be found there, as well as MacCulloch’s tree. This 15-metre-high conifer was ‘frozen in time’ where it stood, preserved when the thick lava flows from the volcano engulfed it around 60 million years ago.
Lara Reid, freelance science writer, says: I first saw MacCulloch’s Tree on the Isle of Mull when I was a young teenager – and the image has remained with me since. To me, it represents so much about both the power of nature and the resilience of it. Fossil Grove in Glasgow appears to defy time itself: it seems the trees were alive only yesterday from the detail and textures in the bark. My two children are delighted by the ‘stone trees’ in the Botanic Gardens in Edinburgh, and I hope these beautiful fossils inspire them to retain a curiosity about Earth’s history as they grow up.