Forests within major cities, such as Table Mountains, Afromontane forests, are constantly subjected to industrial and urban pollution sources. Cape Town is one of the most profound areas in the world for plant extinction and already has a high occurrence of threatened species. The objective of this study was to determine the concentrations of the metals, aluminium and iron, commonly emitted from anthropogenic activities in key forest organisms (mosses, lichens and millipedes), soil and leaf litter in three forests (Platbos, Orange Kloof and Newlands) in the Western Cape, South Africa. In general, the metal concentrations increased with traffic volumes and traffic behaviour (frequent braking and acceleration). Factors, such as the locations of the sites and forests, wind and different accumulation abilities of bioindicators had a notable impact, as did the natural geological origin of aluminium and iron. Of significance in this study was the metal contamination in forests in close proximity of the centre of the city Cape Town.