Trees have the remarkable ability to pass knowledge down to succeeding generations and to survive the ravages of climate change, if only we’d let them alone, according to the German forester Peter Wohlleben. In The Power of Trees (translated by Jane Billinghurst) he explains the significance of leaving ancient forests untouched, and is scathing about the failures in forestry management and the planting of non-native trees for profit. Jill Butler is an ancient tree specialist and a trustee of the Tree Register of the British Isle which records the nation’s ‘champion trees’ – the tallest and biggest trees of their species. But she’s also keen on getting the public involved in helping to find and care for some of the country’s oldest trees with the citizen science project, Ancient Tree Inventory, run by the Woodland Trust. The healing powers of ancient trees is celebrated in stories throughout history, including the great Icelandic sagas. In The Norse Myths That Shape the Way We Think Carolyne Larrington, Professor of medieval European Literature explores the renewal that comes from the roots of Yggdrasill, the World Tree. Producer: Katy Hickman