California's mighty redwoods are going international, cloned in an effort to promote reforestation and deal with climate change.
Although measuring just 18 inches (45 centimeters) tall, the laboratory-produced trees are genetic duplicates of three giants that were cut down in northern California more than a century ago. Remarkably, shoots still emerge from the stumps, including one known as the Fieldbrook Stump, which measures 35 feet (10.7 meters) in diameter. It's believed to be about 4,000 years old. The tree was about 40 stories high before it was felled.