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DURHAM, N.C. – The environmental impacts of rapidly expanding industrial-scale oil palm cultivation in the central African nation of Gabon could be minimized by placing high carbon stock forests and other areas with high conservation value off limits, a new Duke University-led study finds.

“Safeguarding these areas would protect more than 80 percent of Gabon’s land area and more than 90 percent of its forest carbon stocks, while still leaving between 1.2 to 1.7 million hectares – or roughly 3 to 4 million acres of land – that could be converted into oil palm plantations,” said Kemen G. Austin, a doctoral candidate a Duke’s Nicholas School of the Environment, who led the study.  

This remaining land area, which the new study shows is either suitable or moderately suitable for oil palm cultivation, would likely be sufficient to meet the Gabonese government’s goal of producing between one-quarter million and 1 million tons of crude palm oil each year, assuming yields are similar to those reported elsewhere in the region, Austin said.  

“By adopting this sustainable approach, Gabon could achieve its ambitious agricultural expansion objectives while limiting negative consequences for forests, biodiversity and climate emissions,” she said.

Austin conducted the new study with colleagues at Duke, the National Parks Agency of Gabon, the Institute for Tropical Ecology at Gabon’s National Center for Scientific Research, and the University of Stirling (U.K.).

They published their findings January 5 in the peer-reviewed journal Environmental Research Letters.

Many scientists have worried that converting tropical forests in Gabon and other Central African countries into monoculture palm plantations will harm biodiversity and cause a significant spike in climate-warming carbon emissions unless governments enact mandatory policies regulating which forests can be cleared and how much remaining forest must be set aside for conservation. Earlier this year, another Duke-led study showed that developing only low-carbon forests and requiring that one acre of land be set aside for conservation for every 2.6 acres put into production will be essential for achieving net-zero emissions.

To conduct the new study, Austin and her colleagues first estimated the extent and location of suitable land for oil palm cultivation in Gabon, based on an analysis of recent trends in plantation permitting. They then developed maps representing two proposed approaches that could be used to minimize the negative environmental impacts of future expansion.

The high carbon stock (HCS) approach emphasized forest protection and climate-emissions mitigation by protecting forests with more than 75 to 118 tons of above-ground carbon stocks per hectare.

The high conservation value (HCV) approach focused on safeguarding biodiversity and ecosystems by ensuring that oil palm cultivation does not expand into protected areas, intact forests, nationally rare ecosystems, or habitats for threatened, endangered, rare or endemic species.

“We found that by using these approaches to guide future expansion, the Gabonese government could achieve its goals for sustainable oil palm expansion without compromising either HCS or HCV areas,” Austin said.

Because the new analysis was conducted on a national scale, one of its most important roles will be as a guide to help determine priority locations where more intensive field data collection is needed to identify locally significant ecological, social and cultural features and facilitate participatory mapping to reflect the values of local communities.

“Our analysis improves understanding of suitability for oil palm in Gabon, determines how conservation strategies align with national targets for oil palm production, and informs national land-use planning, “Austin said. “This approach provides a useful template for other countries facing similar challenges of reconciling agricultural growth with environmental conservation.”

Funding for the new study came from the National Science Foundation Graduate Research Fellowship Program (#DGE-1106401).


CITATION: “An Assessment of High Carbon Stock and High Conservation Value Approaches to Sustainable Oil Palm Cultivation in Gabon,” Kemen G. Austin, Michelle E. Lee, Connie Clark, Brenna R. Forester, Dean L. Urban, Lee White, Prasad S. Kasibhatla, John R. Poulsen. Environmental Research Letters, Jan. 5, 2017. DOI: 10.1088/1748-9326/aa5437