Dry untreated wood is fine, but the burning of any kind of waste – particularly wood covered in plastic or paint – is both harmful to the environment and against the law, says the Swiss Federal Office for the Environment, Forests and Countryside (Buwal).
Particularly high risk, says Buwal, is wood that has been chemically treated. This includes furniture, scaffolding planks, telegraph poles, and railway sleepers, none of which should be burnt in the open air.