Sunrise over rainforest.
Photo: Susanna Bergström, SLU

A new chapter begins for the restored rainforest in Borneo

News published:  21/03/2025

After nearly three decades of restoration, 18,500 hectares of degraded rainforest in Borneo are recovering. Now begins the next phase—deepening knowledge and ensuring real impact. Recently, over 20 local organizations in Malaysia met to share experiences and shape the way forward.

The rain has been falling for weeks. The forest roads are covered in deep mud, and drivers skillfully navigate their way forward. A collapsed bridge has made some research sites inaccessible. Work in the rainforest happens on nature's terms, as the local communities, companies, and universities that have fought to restore a vast area of forest in northeastern Borneo well understand. The goal has been to make the damaged forest as similar to an undisturbed rainforest as possible. 

"The results are clear; we are well on our way! Tree diversity has increased by 35% in the most damaged areas, and the presence of threatened bird species matches that of undisturbed rainforest," says Ulrik Ilstedt, a researcher at the Swedish University of Agricultural Sciences (SLU), who leads the research in the area.

Two people measure the circumference of a large tree in the rainforest.
The largest planted tree, the dipterocarp Shorea leprosula, was planted in 1998 and now has a diameter of 76 cm and a height of 40 metres.

The project was set to conclude in spring 2025, but all involved parties agree that this is just the beginning of something new.

"This project is unique! The knowledge gained here can be valuable in addressing climate and biodiversity crises. It can help develop and disseminate examples of knowledge-based restoration and sustainable management of native rainforests," says Åsa Skogström Feldt, Head of IKEA Social Entrepreneurship BV and Chair of the Sow a Seed Foundation Board.

Growing interest in native species

In the restored forest, researchers have developed a range of experiments to monitor carbon sequestration, biodiversity, genetic variation, and the properties and functions of different tree species within the ecosystem.

"Interest in using native tree species for restoration is growing both globally and in Sabah. Despite Borneo having over 3,000 native species, research and forestry have mainly focused on exotic species. This has led to knowledge gaps and a lack of knowledge transfer, which can hinder the sustainable use of native ecosystems," says Ulrik Ilstedt.

Ulrik Ilstedt lectures in the rain.
Ulrik Ilstedt talks about ongoing experiments to understand the characteristics of some of the area's most common tree species and where they prefer to grow.

Although native species are rarely used—and when they are, only a few are selected – several initiatives in Sabah offer valuable lessons. Together with Yayasan Sabah and IKEA, SLU organized a workshop with more than 80 participants from over 20 local organizations. The focus was on practitioners – most participants run restoration projects or tree plantations, but government officials and researchers in tropical ecology and forestry also attended.

The collaboration continues

Researchers are now compiling the outcomes of the workshop to analyze the communication and knowledge needs discussed.

"The results will be an important input as we plan the future of the project. What are the needs? Which needs can we address within our project, and can we facilitate knowledge exchange between those who already possess valuable expertise?" says Ulrik Ilstedt.

During the workshop, Yayasan Sabah presented a letter of intent signaling the intention to continue the collaboration. The next step is drafting a more detailed agreement between the parties.

"We look forward to contributing to more research and knowledge dissemination that can support knowledge-based restoration and sustainable forest management," says Åsa Skogström Feldt, Chair of the Sow a Seed Foundation Board.

In an 18,500-hectare area in north-east Borneo, 14,000 hectares of rainforest have been restored since 1998. The entire area is now protected.

The restoration has been carried out in four different phases, with methods adapted to the forest's condition. These range from natural regeneration to planting a diverse selection of local tree species to mimic the original forest structure and biodiversity.

The project is a collaboration between the Malaysian state organization Yayasan Sabah and the global home furnishing company IKEA. Researchers from the Swedish University of Agricultural Sciences (SLU) have been involved from the start, working alongside colleagues from Malaysia, Australia, and the USA to scientifically evaluate the restoration measures and their impacts.

Text and photos: Susanna Bergström, SLU

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