Fashion companies are worried about the source of wood pulp used in the clothing they make. Rising cotton prices have boosted demand for wood-based fabrics such as viscose, rayon and modal, which increasingly involves clearing forests and taking land used by indigenous people. Indonesia is a major producer of wood pulp.

Ralph Lauren is the latest in a growing number of fashion companies to pledge investigation of its supply chain to determine if it is using products from the most destructive regions and stop using those sources by the end of 2017.

In countries like Indonesia, the production of pulp for fabrics has been devastating indigenous forest-dependent communities. Production of wood pulp can involve clearing forests to build eucalyptus plantations, taking land traditionally used by indigenous communities.

It’s estimated Indonesia lost 18.5 million hectares of tree cover from 2001 to 2014. When fashion brands start to take responsibility for their supply chains that can have a real positive impact for forests and the people that depend on them. H&M, Zara, ASOS, Levi Strauss and British fashion designer Stella McCartney have adopted similar sourcing policies. Last year Stella McCartney partnered with environmental non-profit Canopy to encourage clothing companies to stop sourcing fabric from ancient and endangered forests.