Trees in Brazil are using mobiles to call for help

Last updated at 17:00

Trees in Brazil are being fitted with a device which will call for help when they're cut down illegally.

A battery-powered tracker the size of a smart phone is hidden in the branches of a tree and automatically switches on when the tree is chopped down.

The device waits for a mobile signal, which it can pick up from 20 miles away and then calls for help.

When the authorities receive a call, they swoop in and arrest the illegal loggers.

The tracking device can be left in the trees for a year before needing new batteries.