Trees in urban areas do not only contribute energy and clean the air – they are also a significant wellness factor and, therefore, essential. We have developed an identification system that grows with the tree – the patented Arbo tag – because it is more and more important in urban areas to monitor and manage the tree inventories. The tags made of plastic have a star-shaped perforation: the bark simply pushes the marker tag with advancing growth further outward in the direction of the pin end.