Dr Amy Jane Beer explores the marvels of all things arboreal – from the world's loneliest tree that also helped define our current geological era to the 400 year-old apple tree that inspired Newton's theory of gravity. Plus she takes a look at trees' wellbeing benefits too. Curator Matt Pottage explores the concept of Champion Trees, highlighting some of the magnificent specimens to be found at RHS Garden Wisley. And did you know that some conifers are deciduous and offer fabulous autumn colour? Matt is a conifer fanatic and shares some suggestions to light up your autumn garden. And finally... there's a call for citizen scientists as we're on the hunt for a new tree pest with RHS scientist Jassy Draculik. Her 'Check a sweet chestnut' campaign seeks to track the spread of a recent arrival to Britain, the Oriental chestnut gall wasp. Tune in to find out how you can help protect our precious chestnut trees. For links to topics mentioned in the show, please see rhs.org.uk/podcast