Senior lecturer in the School of Earth and Environmental Sciences at Cardiff University, Wales UK. He is a palaeobotanist who specialises in understanding the early radiation of large plants and the birth of forest ecosystems in the Devonian period, about 380 million years ago. His research in these fields has been widely publicised.
He has worldwide experience of fieldwork and museum collections, with an emphasis on the Americas, the Arctic (Greenland, Spitsbergen), and China. He has made research visits to Tomsk, Novosibirsk, Syktyvkar and St Petersburg.