In an attempt to exploit the natural protective properties of tree bark, researchers in Sweden and Latvia have created a water-resistant coating for timber using compounds from birch and spruce bark. This is the first wood-protection coating sourced entirely from tree bark, with no additional chemicals. Durability is a challenge for wood-based materials used in construction as outdoor environments can expose them to moisture, heat, sunlight and microorganisms. Applying a protective coating can prolong the lifespan of such materials, and the wood processing industry currently relies on synthetic coatings that often contain hazardous organic solvents and polymers derived from fossil hydrocarbon resources. …Given bark is often treated as waste or burnt to generate energy, this research adds value to an underused but abundant material.