In the steamy forests of Borneo, a team of scientists has discovered a simple trick to help broken forests heal: cut the vines.
A new study found that cutting lianas—woody vines that climb up trees—helps recovering logged forests grow their canopy three times faster than just planting new trees. The research, published in the journal Current Biology, took place in Sabah on the island of Borneo in Malaysia.
Tropical forests in Southeast Asia are among the tallest in the world. The dominant trees, called dipterocarps, can reach 100 meters (about 330 feet) tall—roughly the height of a 30-story building. But selective logging, where loggers harvest only the biggest trees, leaves scars on the forest that can take decades to heal.
When a forest is disturbed, lianas thrive. These vines are floppy and can't stand upright on their own, so they use trees as scaffolding, climbing all the way to the top to soak up sunlight. Their roots also compete with trees for water and nutrients underground. In disturbed forests, lianas can grow so thick they smother young trees and stop new growth from filling in.
The study was part of the Sabah Biodiversity Experiment, a massive research project covering 500 hectares (about 1,240 acres). The forests there were logged once in the 1980s and are now working to recover, though they have more lianas and a lower canopy than the pristine forests nearby.
In 2002, researchers set up experimental plots and planted young dipterocarp trees in some areas. In half of those plots, they went a step further: they cut down all the lianas. They left other areas alone to grow back on their own.
Over the following years, the team used a technology called LiDAR—rapid laser pulses that create detailed 3D maps—to track how the forest structure changed. By comparing the plots, they found that tree growth accelerated and tree death decreased where lianas had been removed. Canopy height jumped three times faster than in plots with only tree planting.
"This could be a good way, and a reasonably cost-effective way, to go in and restore selectively logged forests," said Toby Jackson, the study's lead researcher and a senior research associate at the University of Bristol in the United Kingdom.
The findings matter because restoring degraded forests is a key tool in fighting climate change. Forests absorb carbon dioxide from the air, and taller, healthier forests can store more carbon. Faster forest recovery means faster climate benefits too.
The scientists say their results offer practical guidance for land managers working to bring Borneo's logged forests back to life.