Have you ever sat against the trunk of a large old tree, looked up into its canopy and wondered what it’s seen in its lifetime? There are many species of tree that survive well beyond a human lifespan, for hundreds of years, and some that can live far longer than that, spanning millennia. What can we learn from large old trees around the world? How do they influence the environment? And how can we preserve them for future generations?

Joining Bridget Kendall to discuss ancient trees are Peter Crane, former director of the Royal Botanic Gardens at Kew in London; Valerie Trouet, Professor at the Laboratory of Tree-Ring Research at the University of Arizona in the US; and conservation biologist, Michael Gaige.

Produced by Jo Impey for BBC World Service

Image: A Bristlecone Pine, one of the oldest living organisms on earth

Image credit: Piriya Photography / Getty Images