Forests provide critical services that support life on Earth, from sustaining biodiversity to storing carbon and helping regulate the climate. Despite growing efforts to protect them, tropical forests continue to face pressure from land conversion and other human activities. A new study examining corporate zero-deforestation and conversion (ZDC) commitments finds that these voluntary initiatives were not the main factor associated with recent reductions in forest loss within palm oil supply chains.

The study, published in the Proceedings of the National Academy of Sciences, was led by Matthieu Stigler of the University of Geneva and involved researchers from UC Santa Barbara, the University of Cambridge, the University of Basel, New York University, and the Transparency for Sustainable Economies (Trase) initiative. Among the co-authors are Dr. Robert Heilmayr, associate professor at UC Santa Barbara’s Bren School of Environmental Science & Management, Principal Investigator at the Marine Science Institute, and Director of the Land & Freshwater Program at the Environmental Market Lab (emLab), and Jason Jon Benedict, Research Specialist in UC Santa Barbara’s Environmental Studies Program.

Deforestation is the permanent clearing of forests for agriculture or other land uses. According to Global Forest Watch, nearly 23 million hectares (about 57 million acres) of natural forest were lost in 2025, with agricultural expansion—particularly for livestock production and palm oil cultivation—responsible for more than half of that loss. In response, governments have adopted forest protection policies, while many companies have introduced voluntary ZDC commitments to remove deforestation from their supply chains.

To assess the impact of these commitments, the researchers compared deforestation trends in palm oil supply chains linked to companies with ZDC commitments to those without them. Although deforestation declined in both groups, the reductions were nearly identical.

“This implies that these companies aren't unique,” Heilmayr said. “Deforestation has dropped dramatically across both companies with and without ZDCs.” So, while these efforts may help protect forests from future pressures, they do not explain the recent decline in deforestation.

The team mapped more than 2,600 plantations connected to approximately 1,200 mills supplying 190 companies. Using public supply chain records and satellite imagery, they found that plantations linked to companies with ZDC commitments experienced a 6.63% decline in deforestation, compared with a 6.50% decline for companies without such commitments. The researchers estimated that ZDCs accounted for only an additional 0.12% reduction in deforestation.

Instead, the findings suggest that government forest protection measures and economic conditions that reduced pressure for agricultural expansion were the primary drivers of declining forest loss.

The researchers note that corporate zero-deforestation commitments could still become more important during periods of greater pressure on forests, such as commodity price increases or weaker conservation policies. Heilmayr and his colleagues are continuing to investigate how corporate initiatives and public policies work together to support long-term reductions in tropical deforestation.

Antoine Guenot at the University of Geneva contributed to this story.

Adapted from original reporting by Harrison Tasoff, “Declines in deforestation aren’t driven by corporate sustainability pledges,” The Current, UC Santa Barbara, 2026.