How Locals Saved ‘the Yosemite of South America’

In central Chile, not far from where the Andes Mountains meet the Pacific Ocean, a vast swath of pristine wilderness is changing hands under the most unusual circumstances.

Roberto Hagemann, a Chilean businessman who owns the 325,000-acre property, has agreed to sell the land to his longtime adversaries, a band of upstart environmentalists who spent years thwarting his efforts to develop the property.

The price: $63 million.

It is a landmark transaction that will preserve some of the most ecologically significant territory in South America. Known as Hacienda Pucheguin, the property is surrounded by national parks and is cut by wild rivers, forests of ancient Alerce trees and the Cochamó Valley, a cathedral of towering granite walls popular with rock climbers around the world.

The deal is also a case study in modern-day conservation. At a moment when ecologically sensitive lands are under threat around the globe, it takes a unique confluence of legal, financial and political resources — plus a bit of luck — to protect them from relentless development.

“This is an irreplaceable place,” said Jeff Parrish, a senior executive at the Nature Conservancy, which is advising the nonprofit group leading the purchase. “We need to make sure that it stays the way nature intended it to be.”

The land Mr. Hagemann came to own is almost entirely untouched by humanity. Over the past century, a few hundred settlers established small farms in the area and were granted property rights. For the most part, however, the area was left alone, providing a verdant habitat for pumas, rare Darwin’s frogs and the endangered South Andean deer.