I'm surprised that I hadn't more about this book, it's really an impressive feat, and both literary and compelling. I didn't know what I was in for, but in a nutshell, there are a handful of characters whose lives are affected in some manner or other by trees. Eventually their stories converge and branch. Along the way, the author shares lots of cool facts about trees and forests (not unlike The Hidden Life of Trees, except of course that this is fiction!). As a few of the characters join protests to protect forests, conflicts arise, many of which seem to be based on real life events. This book raises questions about environmentalism, activism, sentience, ecoterrorism, etc. etc.
Be forewarned that this book is massive! In that respect and its subject matter, I'd liken it to Annie Proulx's The Barkskins. Yet, I think many people would find it worth their while, as it's thought-provoking and entertaining both. The audio is well-read, though I think I would have liked the print version as well.