On the outskirts of Hamburg, Dr Gerald Koch is surrounded by wooden objects - chairs, board games, paint brushes - ready for inspection. His team of scientists at the Thünen Institute of Wood Research are known as the timber detectives. They spend their days putting wood samples under the microscope to find out where they've come from, and if they’re suspect.

Berlin based environmental journalist Becca Warner explores the ongoing problem of illegal deforestation.

Why is it proving so hard to tackle, despite tightening EU regulations? What are the consequences for those living in Papua New Guinea where much of this timber originates? And what makes this group of German scientists so important in the battle to protect the world’s forests?

Presenter: Becca Warner

A 4 kicks production for the BBC World Service.

Image: Gerald Koch and Becca Warner inspect timber samples (Credit: Tom Pooley)

This programme has been edited for clarity.