Harry Jacques, Solok, Indonesia (Thomson Reuters Foundation) – Clipped onto a rope, climbing high up in a tree swaying in gusts of wind, Topher White finally reaches the roof of the rainforest and opens a laptop to run checks on a machine he built to transmit 24-hour live sound from the surrounding forest.
The machine is one of 27 "Guardian" sensors eavesdropping on forests in Indonesia's West Sumatra province, to listen out for chainsaws as a way to tackle illegal logging in the region.
Over the next five or six years, White hopes to install tens of thousands of these audio sensors in forests around the world. "We're basically building a nervous system for the natural world," he said.
White, 39, got the idea to use sound in environmental protection ten years ago, while volunteering at a conservation project for gibbons in Borneo.
"You couldn't really monitor (the forest reservation) with people walking around, but sound seemed like a good way to capture really anything," he told the Thomson Reuters Foundation.
With a background in engineering, White spent nearly a year building an audio detection sensor using an old mobile phone, solar panels and a microphone, then returned to Indonesia to test the system.
Today, White's nonprofit, Rainforest Connection, is recording sounds to protect nature in a dozen countries with funding from some of the world's largest technology companies, including Google and Huawei.
Incoming audio streams, from the Amazon to the Philippines, are analysed by artificial intelligence (AI) trained to pick out desired information, from the sounds of logging to bird calls.
If the system hears a chainsaw, it sends an alert via an app to community patrols, who can check on the ground for logging.
Since it was installed more than a year ago, local monitors say the system has made their jobs easier as they help with Indonesia's crackdown on forest encroachment, which includes tougher law enforcement.
"(Logging) has totally stopped – people are afraid of coming to this area," said patroller Jasrialdi, who goes by one name like many Indonesians.
Crackdown on logging
The canopy sensor White was checking in West Sumatra's Solok regency is less than an hour's walk through the forest from the road leading to Sirukam, a village sustained mainly by farming.
Until recently, about 200 of Sirukam's 6,000 residents opted instead for better-paid work illegally extracting timber from the forest, according to Medison, who heads the LPHM, a local forestry agency.
While cutting down some trees for community use – such as building a house – is often tolerated in Indonesia, logging timber to sell is illegal, he explained.
"There used to be no protection of the forest," said Romi Febriandi, the elected head of the village government.
Arief Wijaya, senior manager of climate, forests and oceans at the World Resources Institute (WRI) in Indonesia, said most deforestation in the country occurs due to land clearing for extractive industries.
"But addressing the issue of improper community logging is also crucial," he said in an online interview.
According to Global Forest Watch, a satellite monitoring service run by WRI, Indonesia's humid old-growth forest – seen as vital for storing carbon dioxide and helping curb climate change – shrank 10% from 2002 to 2019, but the rate of tree loss decreased in the last few years.
WRI data show production from Indonesia's logging concessions declined between 2013 and 2018, but timber harvested by communities from forests like Sirukam increased by more than 50% during the same period.
In Sirukam, a tougher approach to enforcing rules against cutting down forest trees has squeezed timber trading in the area, according to former loggers and the local government.
The crackdown led Afriadi, not his real name, to ditch logging for rice farming in 2018.
The middle-aged man, dressed in a cap and batik shirt, who agreed to speak only on condition of anonymity, had taken up logging nearly two decades ago. "There were no other jobs," he said.
Using chainsaws and ropes, Afriadi hauled trees out of challenging terrain – hazardous work that saw one of his team die in an accident – for which he earned up to 1.5 million rupiah ($107) per month.
Today, he makes a fraction of that as a casual labourer while barely feeding his family with what he grows on the farm.
He still fears arrest for his past as a logger. "It's better to work on the farm because of that risk," he said.
A view of the forest in Solok regency, West Sumatra province, Indonesia, on December 12, 2020. Thomson Reuters Foundation/Harry Jacques
As well as tracking forest sounds, White's technology is also listening out for whales wandering into Vancouver's shipping lanes and gunshots in a Greek national park to stop hunting.
The AI has gone through six updates, deepening its understanding of the natural world with each iteration.
White said he can tell just by glancing at a spectrogram if the system is hearing a bird or a primate.
And with engineers training the AI to identify more than 100 species with precision, he hopes Rainforest Connection's systems could prove a "goldmine" for researchers.
"We would have to be doing something very wrong not to make some major ecological discoveries over the next few years," he added.
The sensors stream audio to the cloud over a mobile phone network, which has so far limited their application to areas with viable phone reception.
To tackle that problem, the group is planning to install 32 new satellite sensors in Brazil in March, and a cheaper offline model – which stores the audio recording for someone to pick up later – is being manufactured for about $100.
Yozarwardi Usama Putra, head of West Sumatra's forestry department, said he would like to expand the project's "early-warning system" beyond the 27 sensors currently installed around the province.
Besides cracking down on logging, Indonesia is also working to encourage non-timber forest enterprises, he noted, adding the West Sumatra government is helping communities access equipment to cultivate and process goods from oyster mushrooms to coffee.
This year, Rainforest Connection plans to finish collecting data for peer review from Indonesia, Peru and Romania to prove the system does help curb logging, which White hopes will prompt governments to consider using the technology at a larger scale.
But some ex-loggers say protecting Indonesia's forests comes at the cost of their livelihoods – and their voices have yet to be heard.
Afriadi's small rice field produces just enough for his family to eat. His work as a labourer brings in 70,000 rupiah per day, but he only earns that on a handful of days each month.
Without the income from tree-cutting, he fears he may not be able to provide for his children. "I am very worried," he said.
[Reporting by Harry Jacques; Editing by Jumana Farouky and Megan Rowling.]