* A BBC RADIO 4 BOOK OF THE WEEK * ''The very treeline is on the move: a devastating image. This book is an evocative, wise and unflinching exploration of what it will mean for humanity.'' Jay Griffiths, author of WildA ground-breaking and beautifully written investigation into the Arctic Treeline with an urgent environmental messageThe Arctic treeline is the frontline of climate change, where the trees have been creeping towards the pole for fifty years alreadyThese vast swathes of forests, which encircle the north of the globe in an almost unbroken green ring, comprise the world''s second largest biome.Scientists are only just beginning to understand the astonishing significance of these northern forests for all life on EarthSix tree species - Scots pine, birch, larch, spruce, poplar and rowan - form the central protagonists of Ben Rawlence''s story. In Scotland, northern Scandinavia, Siberia, Alaska, Canada and Greenland, he discovers what these trees and the people who live and wor