This episode is about trees; losing them, planting them, protecting them and the amazing ecosystems they support. We hear from former NASA and Apple engineer turned YouTuber, Mark Rober, who has millions of subscribers to his YouTube channel. He reflects on galvanising a youth movement in the US with fellow YouTuber MrBeast to plant 20 million trees. Plus, Bryna Griffin, Head of Forests Programme for BirdLife International, talks about Trillion Trees’ global vision to protect and restore a trillion trees.