For centuries, people have understood that forests, and our utilisation of them, influence the climate. With modern environmental concerns, there is now scientific, governmental, and popular interest in planting trees for climate protection. This book examines the historical origins of the idea that forests influence climate, the bitter controversy that ended the science, and its modern rebirth. Spanning the 1500s to the present, it provides a broad perspective across the physical and biological sciences, as well as the humanities, to explain the many ways forests influence climate. It describes their use in climate-smart forestry and as a natural climate solution, and demonstrates that in the forest-climate question, human and sylvan fates are linked. Accessibly written with minimal mathematics, it is ideal for students in environmental and related sciences, as well as anyone with an interest in understanding the environmental workings of forests and their interactions with climate.