This is a single branch of rowan (mountain ash, Sorbus aucuparia). Rowan has been much used in studies around Norwegian aluminium smelters so there is a good literature on the species. However, note that some leaflets have necrotic patches, some tip distortion and marginal chlorosis. This degree of variation makes it difficult to score injury in surveys. The Norwegians have used it most successfully as a bioaccumulator to record fluoride concentrations.