In 2012, Topher White visited a wildlife sanctuary in Indonesia. He was hiking through the rain forest when he came across a man cutting down a huge tree.
White was watching illegal logging in action. Illegal logging is a big problem in rain forests around the world. It contributes to climate change and destroys habitats for forest creatures.
The logger fled the scene. But the experience bothered White. He knew the wildlife sanctuary employed rangers to watch out for illegal loggers. But the guards hadn’t known about the man White saw. How did they miss him?
White, a trained engineer, thought technology could help fight deforestation. “The rain forest is a noisy place. But it’s also a noisy thing to cut a tree down,” he told TIME for Kids. “It struck me that there had to be a way to hear this.”
White created a device he calls a Guardian. It’s a recycled smartphone powered by solar panels. Guardians can pick up the sound of a chain saw from nearly a mile away. They are mounted on trees.
When a Guardian detects a chain saw, it sends an alert to rangers. The rangers then set off to stop the illegal activity.
“If you respond the moment you get the alert, there’s a chance that you can show up before much of the tree has even been cut,” White says.
White installed the first Guardians in Indonesia, at the wildlife sanctuary where he had the idea for the project. Two days later, the devices helped rangers interrupt a logger. “That convinced me others could use this too,” White says.
White started a nonprofit group called Rainforest Connection. It builds and installs Guardians all over the world. The group now covers 90,000 square miles of rain forest in 10 countries.