When David Milarch first visited Northern California in 1968, he thought he would see avenues of coast redwoods 100 miles long. What he found instead was a "moonscape," he said. Nearly 40 years later, the Michigan arborist has returned to the region to realize his dream of preserving and restoring the most ancient of these trees using the latest advances in genetic cloning.

"What does this tree's immune system have in it that it has survived when other trees haven't?" Milarch asked, leaning against a massive, shaggy trunk of a redwood he's dubbed "Grandma." He estimates the tree is at least 800 years old.

About 95 percent of the original forest has been cut down over the last few hundred years.