When the oldest trees in the world suddenly start dying - across North America, Europe and the Amazon - it's time to pay attention. Humans have cut down the biggest and best trees and left the runts behind. What does that mean for the genetic fitness of our forests? No one knows for sure, for trees and forests are poorly understood on almost all levels. What we do know, however, suggests that what trees do is essential. When tree leaves decompose, they leach acids into the ocean that help fertilize plankton. When plankton thrive, so does the rest of the food chain. Trees are also nature's water filters, capable of cleaning up the most toxic wastes, including explosives, solvents and organic wastes. They sequester carbon dioxide, act as nature's heat shields, keeping cities 10 or more degrees cooler, and also release vast clouds of beneficial chemicals - some of which are anti-bacterial, anti-fungal and anti-viral.

We need to learn much more about trees. But, meantime, we need to preserve them.Jim Robbins' book is a remarkable exploration of the power of trees and the story of a farmer named David Milarch, co-founder of the Champion Tree Project, who has been cloning some of the world's oldest and largest trees to protect their genetics - from California redwoods to the oaks of Ireland.