Evidence that the approach helps to save trees, preserve ecosystems and reduce carbon emissions is often hard to come by. But it can succeed if it’s done right, says an economist.

Natural ecosystems do us countless favors, from purifying the water and air to harboring and nurturing the pollinators we need to grow much of our food. Yet landowners may have other, more directly profitable uses in mind for their land, be it growing crops, ranching cattle or building a factory, apartment building or office complex.

It might seem only fair, then, that if we want people to leave their wildland intact for the greater good, we should pitch in to alleviate the opportunity cost: the money a person might have made from developing the land instead. But how do we organize this in a fair and effective way?

Economist Sven Wunder, principal scientist at the European Forest Institute and senior associate at the Center for International Forestry Research, has spent years investigating just this. Wunder, who shared his insights in two 2020 articles in the Annual Review of Resource Economics, told Knowable Magazine that evidence for the effectiveness of such projects is often sorely lacking — but it’s within our reach to do better.