Musicians often sing about environmental problems, but what about the environmental issues tied up with the materials from which their guitars are made?
Around 2.6 million guitars are produced annually, but the timber supply chains on which the guitar industry relies have long been secretive. Many sources of wood are from places with historical legacies of environmental conflict, colonial violence and dispossession - such as rosewoods from Brazil and spruces from the Pacific Northwest.
Professor Chris Gibson and his colleague Andrew Warren, both from the University of Wollongong in Australia, spent six years tracing guitar-making across five continents. Chris joins the show to discuss what they discovered on their travels.