On Jan. 15, 2012, Greg Asner took off from Panama City, Panama in a twin-turboprop Dornier 228 with two pilots, three technicians and some highly specialized equipment. Traveling west at 150 knots per hour, the plane rose above the skyscrapers and suburban developments of the capital city and swooped over Gatún Lake’s Barro Colorado Nature Monument, with its towering espave and ceiba trees. It flew over cleared grasslands and cattle ranches and skirted the steep, wet forests trailing beaches down to the Caribbean. It would soon head east to the wild, largely unpopulated Darien region, with its network of mangroves, rainforests and swamps.

Asner, a Stanford professor and staff ecologist at the Carnegie Institute for Science in California, was on a unique quest. For 15 years, he had been developing the equipment, the team and the mathematical algorithms necessary to measure the carbon stored in forests. Now, at the invitation of the Smithsonian Tropical Research Institute (STRI) and the Panamanian government, he would be undertaking a feat never before accomplished: mapping the carbon stocks of an entire country.