By: - Climate DepotJuly 20, 2016 1:45 PM

CAMP NELSON, Calif. (AP) — At the foot of a giant sequoia in California’s Sierra Nevada, two arborists stepped into harnesses then inched up ropes more than 20 stories into the dizzying canopy of a tree that survived thousands of years, enduring drought, wildfire and disease.

There, the arborists clipped off tips of young branches to be hand-delivered across the country, cloned in a lab and eventually planted in a forest in some other part of the world.

The two are part of a cadre of modern day Johnny Appleseeds who believe California’s giant sequoias and coastal redwoods are blessed with some of the heartiest genetics of any trees on Earth – and that propagating them will help reverse climate change, at least in a small way.

“It’s a biological miracle,” said tree climber Jim Clark, firmly back on the ground and holding a green sprig to his lips as if to kiss it. “This piece of tissue … can be rooted, and we have a miniature 3,000-year-old