In a special episode of the podcast, host Rowan Hooper visits Newlands Corner in the North Downs in southern England, the site of one of the oldest and most significant populations of wild yews growing anywhere in the world.Yew trees are familiar from churchyards and are also revered by pagans and shamans. They can live for many hundreds of years. The grove at Newlands Corner is an exceptional ecosystem, with yews over 1000 years old, but they are declining, losing their needles and slowly dying. Rowan meets arboreal scientist Geoff Monck of Treecosystems, who specialises in surveying and restoring arboreal ecosystems.The cause of the decline in ancient yews has many factors, but the impact of nitrates in rainwater and in run-off from crop fields is perhaps the most important. Rowan hears how nitrates are changing the way the wood wide web operates, and how we might be able to fix it. New Scientist podcasts are freely available. Subscribe at newscientist.com/podcasts. Hosted on Acast. See acast.com/privacy for more information.