This presentation is about my work over the past thirty years and my study of forests around the world. I have travelled from the Arctic through the temperate forests of Britain and Europe. Then on into the tropics and way down into the southern hemisphere. The presentation is about what forest actually is, how it works and how it keeps us all alive. The presentation is about biodiversity and the fascinating ecology which surrounds it. It is about the consequences of long term decline in diversity and what that implies. The presentation begins with a question. Why do trees, woodpeckers, sperm whales, salmon, bears, flies and hummingbirds need each other? The presentation will end with a question. Can we survive without that connection?