"Hidden away in foggy, uncharted rain forest valleys in Northern California are the tallest organisms the world has ever sustained--the coast redwood trees. 96% of the ancient redwood forests have been logged, but the fragments that remain are among the great wonders of nature. The biggest redwoods can rise more than thirty-five stories above the ground, forming cathedral-like structures in the air. Until recently, the canopy at the tops of these...

These giant trees stretch more than 300 feet above the ground, with hidden gardens and mysterious predators thriving within their canopy. Obsessive redwood climber Steve Sillett of Humboldt State University investigates their monster crowns, tallying biological material and discovering new record-breaking trees, while escaping falling branches and crashing trees in the process. Explorer-in-Residence Mike Fay charts the redwood range.