Bruno Coutinho stood on a dusty road, quietly weeping.

As a biologist and a geographer at Conservation International, Coutinho has spent a career designing and mapping landscapes on screens. He had not expected one of those maps to bring him to tears.

The road beneath his feet, once pixels on a monitor, was now a steep bend, following the river's swale below. Around him, the Cerrado — a mix of savanna and woodlands in southwestern Brazil — was returning. The canopy slowly closed, as tenacious, blooming layers of trees and shrubs pushed up through old pasture grass.

Standing nearby, Mark Wishnie of BTG Pactual — the Brazilian investment firm that had built all of this — watched him. “We've all worked on projects where you have a beautiful idea,” Wishnie said later.…