City of Melbourne works closely with a number of organisations to actively monitor and manage threats and attacks from pest and disease. City of Melbourne has low diversity in its tree stock which leaves it highly vulnerable to loss through pest and disease. Just three species – Plane, Elm and Red River Gum, make up almost 35 per cent of Melbourne’s trees.
Current Issues: Myrtle Rust
Myrtle rust is a fungus which infects plants belonging to the Myrtaceae family. Infection will stunt growth and in severe cases and prolonged infection will cause plants to die. Younger plants are more susceptible to this disease.
Over 43 per cent of the City of Melbourne’s trees belong to the Myrtaceae family. This disease has not yet been detected in Victoria. City of Melbourne is working actively with the Department of Primary Industries to actively monitor this disease.
Allergies
Concerns have been raised in a number of cities around the world regarding human allergenic and irritant responses to London Plane Trees.
London Plane Trees (Platanus x acerifolia) account for almost 12 per cent of the tree population in the municipality. Most of these trees are between 20 and 50 years of age and contribute significant amenity and canopy cover. These trees have an estimated amenity value of around $55,000,000.00.
The leaf and fruit hairs of the London Plane trees are known to cause physical irritation. However, plane tree pollen is not considered to be a primary allergen.
In response to ongoing community concerns, the City of Melbourne has ceased planting London Plane trees. The preferred species for the municipality is now the Digitate Plane tree (Platanus orientalis ‘Digitata’). This species has considerably less fine hairs on their leaves and therefore are not as problematic as an irritant. It is also considered to be a more robust urban tree.
Further information