[NEW DELHI] Environmentalists have long worried about the negative impacts of oil palm cultivation, especially on biodiversity when forests are burned and turned into plantations.

Now researchers say there is a solution that could mitigate the damage.

Setting up forests or “tree islands” in large oil palm farms can help restore biodiversity and ecosystems by aiding the natural regeneration of native trees, their study suggests.

Increasing international demand for palm oil triggered vast forest destruction in Indonesia and Malaysia—responsible for 85 per cent of global palm oil production.

Land cleared for an oil palm plantation, East Kalimantan, Indonesia. Photo by Mokhamad Edliadi/CIFOR

These plantations have been a catastrophe for endangered animals, such as tigers in Indonesia’s Sumatra. They also aggravate conflicts with local Indonesian communities on traditional land rights.

In 2023, with the production of 47 million tonnes of crude palm oil, Indonesia became the leading palm oil exporter in the world. But in the past two decades, the country has also lost 3 million hectares of natural forest areas, thanks to the spread of oil palm plantations.

Published this month in the journal Science, the study says the extensive conversion of Southeast Asian natural forests into plantations of African oil palm (Elaeis guineensis Jacq.) has led to alarming losses of biodiversity, ecosystem functioning and evolutionary history.

The researchers say it’s essential to protect the remaining forests to conserve their rich, tropical biodiversity.

The orangutan (Pongo pygmaeus), resident in East Kalimantan, Indonesia is currently on the ICUN Red List of endangered species, facing habitat loss, fires, habitat exploitation and illegal logging, habitat fragmentation, hunting and the pet trade. Photo by Moses Ceaser/CIFOR.

In the study, the researchers looked at how ecological restoration contributes to the recovery of biodiversity in oil palm agricultural areas in Sumatra. The researchers strategically planted trees to set up 52 tree islands of different sizes and diversity levels to find out how the restoration strategies influence biodiversity in the oil palm agricultural area.

“The main implication of our study is that it supports the use of tree islands, strategically planted patches of native vegetation within agricultural landscapes, as a viable approach to restoring plant diversity in oil palm landscapes,” said Gustavo Paterno, an author of the study and postdoctoral researcher at Göttingen University in Germany.

The researchers observed that six years after being set up, tree islands hosted a broad range of native species, including more than 2,700 woody plant species.

They say developing large and diverse tree islands is important for conserving “rare, endemic, and forest-associated” plant species in oil palm agricultural areas.

Tree islands speed up the natural revival of native trees by helping the spread of seeds by birds and wind, according to the study. This process improves biodiversity, important for developing resilient ecosystems that can resist climate change.

“Our study demonstrates the potential of tree islands to transform biodiversity-poor agricultural lands into biodiversity-enriched ecosystems, offering a promising restoration strategy for oil palm landscapes,” said Paterno.

“Based on these results, we recommend the establishment of large tree islands with a high initial diversity of planted tree species to promote biodiversity recovery within conventional oil palm plantations,” he told SciDev.Net.

However, Johny Tasirin, from the faculty of agriculture at the Indonesia-based Sam Ratulangi University, believes the solution has limitations.

“Overall, the native plants, birds, and insect diversity may increase, but I still doubt about recovering the large mammalian species which are a typical part of natural forests in Sumatra,” he told SciDev.Net.

Clara Zemp, assistant professor and head of the Conservation Biology Lab at the University of Neuchâtel in Switzerland, said: “Tree islands in oil palm landscapes do not replace existing rainforests that have unique value for biodiversity.

“Hence, the top priority is to protect remaining patches of natural forests and to avoid further deforestation.”

This piece was produced by SciDev.Net’s Asia & Pacific desk.