When a tree falls to illegal loggers in the forest of the Kalaweit Supayang Nature Conservation Reserve for gibbons in West Sumatra, Indonesia, it most definitely makes a sound—and generates a text message to alert reserve managers. Last summer a tiny, nonprofit start-up called Rainforest Connection installed a handful of old, donated smartphones, each tricked out with a solar charger and reprogrammed to conduct audio surveillance, into the forest canopy. The system quickly brought logging to a halt, says Topher White, a 31-year-old physicist who designed the system and founded the outfit.

Now, with the help of the Zoological Society of London (ZSL) and the KfW development bank in Germany, Rainforest Connection is preparing to deploy dozens of such listening devices in equatorial Africa to protect endangered forest elephants and their habitats. “This technology enables the forest to talk to the world,” says musician Neil Young in a video produced by Rainforest Connection for a fund-raising campaign it plans to launch today on Kickstarter. “The forest can speak—and you can hear it. They can hear the first saw, they can hear the rifle shots when people are shooting animals and shouldn’t be. They can tell when the forest is under attack by people who are breaking the law.”

The smartphones, encased in waterproof housings and attached to a cluster of solar cells, look a bit like large, black flowers. White mounts them high in the canopy, where they are hard to spot. The devices periodically record snippets of audio, which they transmit over the cheap local cellular network to a central server. The computer analyzes the audio waveforms as they come in. If the software detects the sound of chain saws, it triangulates the position of the logging and sends the info to workers at the preserve.

Within 24 hours of activating four strategically positioned bugs in the Kalaweit reserve, White says, the devices picked up illegal loggers and dispatched authorities. After two weeks of operation loggers stopped entering the 135-hectare region covered by the system. A year on, they have not returned, he says.

The project in Africa will be much larger, involving about 30 listening devices in the canopy of a 200,000-hectare forest in Cameroon that is important habitat for endangered elephants and lowland gorillas as well as chimpanzees. Each phone can pick up saws up to a kilometer away, so the network will directly protect roughly 10,000 hectares. By positioning the bugs around the periphery of the forest near roads and trails frequented by poachers and illegal loggers, White and the ZSL hope to effectively defend a large fraction of the forest.

The area includes three Forest Stewardship Council–certified logging concessions where timber is harvested legally—and on prearranged, sustainable timetables. “Beyond chain saws we will also be detecting vehicle movements along roads, allowing authorities to note when trucks are moving logs on roads where [or when] no such activity is planned or sanctioned,” White says. “To be blunt, providing an accounting for corruption within the concession—including illegal logging by those who work there—is amongst the primary goals of the pilot.”

“If it works as well as we hope,” says Lauren Redmore of the ZSL, “we will certainly look to expand to a larger deployment”—although, she and White acknowledge, cellular data coverage could be a limiting factor in remote areas.

High-tech surveillance is clearly not a panacea for deforestation, which continues to proceed at an alarming pace. To fight the problem, “we’ve used lawsuits, we’ve used government regulations, we’ve used consumer boycotts, we’ve used market pressure campaigns—and we need to continue using all of those avenues,” says Randy Hayes, founder of the Rainforest Action Network. “But frankly, we need more tools. And this is the most exciting, critical new tool that I’ve seen that I think can help us get the job done.”