Cattle ranching has been the primary driver of deforestation in the Brazilian Amazon, as huge swaths of rainforest are cleared to make way for agriculture. But “zero-deforestation agreements” signed by some of Brazil’s big beef industry players appear to be helping reduce the destruction, a new study concludes.

“We’re showing that these commitments can [produce] meaningful change on the ground,” says land use researcher Holly Gibbs of the University of Wisconsin, Madison, a lead author of the study, published online this week in Conservation Letters.

Cattle ranching in the Brazilian Amazon has seen tremendous growth in the past decade. The herd expanded 200% between 1993 and 2013, researchers estimate, reaching a total of nearly 60 million individuals. During that time, an area of forest the size of Italy was cleared. Nearly half of the clearing, 40%, occurred in the state of Pará, home to nearly one-third of Brazil’s cattle.

In 2009, nongovernmental organizations and the state’s federal prosecutor put pressure on companies to reduce deforestation associated with cattle production. The federal prosecutor began suing ranchers that had illegally cleared forest and threatened to sue retailers in an effort to persuade them to boycott slaughterhouses associated with forest-clearing ranches. In response, Brazil’s three largest meatpacking companies (JBS, Marfrig, and Minerva) signed an agreement with the government, stating they would stop purchasing directly from ranches that cleared more forest than legally permitted. A few months later, the trio of firms signed a more stringent agreement with Greenpeace, known as the G4 agreement, under which they committed to buy only from direct suppliers that reduced deforestation to zero. Both agreements also required supplying ranchers to enroll on a public environmental registry, which identified the boundaries of their ranches and enabled monitoring of changes in forest cover.

Within months, nearly 60% of the suppliers had registered, and compliance reached 96% by 2013. Most of the ranchers—85%—said they signed up so they could sell cows to JBS.

By 2013, “recent deforestation” had occurred on just 4% of the ranches supplying cows to the slaughterhouses, down from 36% of ranches in 2009. That suggests the slaughterhouses were actively avoiding ranches with deforestation problems, the researchers write, and that “targeted supply chain interventions can produce results in a period of months rather than years.”

One key, Gibbs says, is that it is easier for the slaughterhouses to influence rancher behavior than government regulators, who are often located in distant offices. “The slaughterhouses … are much more embedded in those deforestation fronts and they have daily interactions with the farmers and the ranchers,” she says. “This allows them a lot more leverage to be able to immediately restrict market access or help to enforce these policies.”

It’s not clear, however, that the agreements—which have spread to other Brazilian beef-producing states—can defeat deforestation, says Avery Cohn, a social scientist at Tufts University in Medford, Massachusetts. “I see these findings as a building block towards understanding what kinds of levers can be effective,” he says, “but they're not necessarily evidence that we know how to control deforestation.”

One problem is that the agreements leave room for so-called cattle laundering. In laundering, ranchers who are not direct suppliers to the slaughterhouses that signed the agreements raise and fatten their cattle on properties not covered by the pacts. Then, they move or sell the animals to ranchers who are direct suppliers. That loophole could be closed if a database that covers all of the animals and where they are being transported were publicly available, Gibbs says.

Another challenge is improving the monitoring of deforestation on ranches. JBS, Marfrig, and Minerva currently “monitor deforestation on the farms that produce about half of the cattle that are slaughtered in Brazil,” Gibbs says. “But that means the other half are being produced on properties that have no monitoring.”

Still, she says the Brazilian experience may hold lessons for other nations facing similar issues. Brazil’s “cattle sector in particular has been very recalcitrant [in addressing deforestation],” she says. “So it's been really exciting to see this particular industry really stepping up to make changes.”