In this special edition of Countryfile, John Craven is in Somerset where something strange is going on: a mast. Once every ten years or so, trees, shrubs and hedgerows all produce a super abundance of fruit. John finds out it is nature's way of compensating for bad seasons. He then heads for the hedgerows, where amongst the blackberries he finds the odd wild apple tree - the result of casually discarded apple cores. He starts picking and soon has enough to take along to a community apple pressing event, where he catches up with the original cider-drinking superstars, The Wurzels.During his Wild Harvest, John looks back at some of the best of all things autumnal to have featured on Countryfile. Like the time Matt hooked up with Antony Worrall Thompson to celebrate British sweet chestnuts. Or when Julia got a lesson in the science of autumn from BBC weatherman John Hammond. And the time Ellie went to Wales to discover the dark arts of mushroom growing.