Environmental factors associated with a disorder affecting tree species on the coast of New South Wales with particular reference to Norfolk Island pines Araucaria heterophylla

Abstract Like other woody seaside plants, Norfolk Island pines have deteriorated, and many have died, on parts of the coast of New South Wales. The disorder appears as a necrosis, which typically begins at the lower seaward side and subsequently extends all over the crown. The intensity of the disorder is directly associated with foliar sodium content and inversely with distance from (a) marine sewer outfalls and (b) the coast. It seems that the uptake of large amounts of sodium is mediated by surfactants discharged in sewage.