A forest project that uses solar-powered smartphones hanging from trees to listen for the sounds of chainsaws could help stop illegal logging

Not hard to hear (Image: Yusuf Ahmad/Reuters)

A CHAINSAW revs in a remote swathe of the Indonesian rainforest. Within minutes, rangers appear as if from nowhere, stopping illegal loggers in their tracks and saving countless trees. How did they know? A tip off from a recycled cellphone hanging hundreds of metres away in the forest.

That’s the vision of Topher White, founder of Rainforest Connection, based in San Francisco. The non-profit organisation is launching a pilot project this month in the forests of Indonesia that uses modified Android smartphones to record and identify the sound-signatures of chainsaws.

At first, Rainforest Connection will use new phones donated for the trial, though White ultimately plans to use recycled handsets that supporters contribute when they upgrade to the latest model. The phones are outfitted with solar panels specifically designed to take advantage of the brief periods when light reaches the forest floor. Their microphones stay on at all times, and software listens for the telltale growl of a chainsaw, which triggers an alert.


Initially, only rangers will be notified, but White hopes to release a free app that lets anyone receive real-time alerts with the audio that the phones pick up and the location. “We want to make people feel like they are taking part in the dramatic events on the front lines of environmental protection,” he says.

Current efforts to stop loggers in Indonesia are limited. “We can find out how much forest has been cut using satellite images, but we find out after, so we cannot trace when it happens,” says Dwiati Novita Rini, who works on reforestation of cleared land in Sumatra with Birdlife International. Conservation groups can also pay police to perform aerial surveys of areas vulnerable to logging, but they are too expensive to do frequently.

For its initial trial, Rainforest Connection will work with the conservation group Kalaweit to place and test 15 phone rigs in the 25,000-hectare Air Tarusan reserve in western Sumatra. White hopes each phone will have a listening radius of 0.5 kilometres, providing a low-cost way to monitor remote stretches of jungle.

Indonesia loses more than a million hectares of forest a year, according to an estimate by Rainforest Action Network. The country’s rainforest is the third largest in the world, and home to many unique native species of plants and animals. But more than half of it has been cleared since the 1960s.

Eventually, White hopes to simplify the technology so that locals can plug a phone into a box, nail it to a tree, and begin tracking loggers right away. “We’ll ultimately rely upon locals to intervene when an ‘event’ is detected. Making it simple, effective and accessible for them is our first priority.”

This article appeared in print under the headline “Trunk call to save forest”