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.
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.
Photo: Susanna Bergström, SLU
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.
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 talks about ongoing experiments to understand the characteristics of some of the area's most common tree species and where they prefer to grow.
Photo: Susanna Bergström, SLU
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.
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.
