The Northern Forests

From the Arctic to the southern United States stretches the largest forest in the world. David Attenborough roams from north to south through this spectacular woodland, starting amid conifers high in the Arctic Circle and ending among the giant sequoia trees of the Sierra Nevada. Among the wildlife he encounters are huge great grey owls, sapsucker woodpeckers, hummingbirds, raccoons, chipmunks and burrowing tortoises.