Melbourne Water is committed to preserving and protecting our water catchments and the local environment in your area. We are removing the infestation of ‘giant pine scale’ from Cardinia Reservoir and replanting the affected areas with native plants. These works will protect the local environment from further damage from giant pine scale and ensure the long-term biodiversity of the area.
What is giant pine scale?
Giant pine scale is a tiny scale insect that feeds on the sap of pine, fir and spruce trees and spreads by crawling to nearby host trees. Trees infested with giant pine scale have a white wax that resembles cotton wool on their trunks and branches and will typically dry up and die as a result of the insects feeding on the tree’s sap. Giant pine scale is notoriously very difficult to manage – the insects have no known predators in Australia and there are no effective chemical treatment options available.
Giant pine scale at Cardinia Reservoir
Giant pine scale was confirmed in Melbourne for the first time in 2014, and first detected in Cardinia Reservoir in 2017 in approximately 20 trees. Our efforts to contain the spread have had limited impact, with the estimated number of infested trees now at around 500, covering approximately 14 hectares. We anticipate all of these infested trees will die in the next 5 to 10 years.
There are 15,000 to 20,000 pine trees growing in the Cardinia Reservoir catchment. Removing the trees infested with giant pine scale is necessary to prevent the broader risk of infestation to the surrounding healthy pine trees and across the region. Dying trees are a safety hazard as they increase the fuel load in the event of a bushfire, as well as having the potential to fall on land managers working in the catchment.
Safe tree removal and catchment replanting
Melbourne Water has worked closely with experts including the Department of Environment, Energy and Climate Action (DEECA) to build a Biosecurity Plan for safe treatment and removal of the pine trees. The highest standard of equipment hygiene will be used to avoid spreading giant pine scale further within the reservoir or surrounding area.
The affected areas will be revegetated and replanted with more than 33,000 native trees and plants, commencing in Autumn 2024. This will ensure the long-term biodiversity of the catchment.
Minimal local impact
There is unlikely to be any direct local impact to people outside the closed catchment during these works. There may be some increased vehicle movement around the catchment and possible noise from machinery operating on site.
Visitors to the area and particularly to Cardinia Reservoir Park will see some areas in the closed catchment where the works are occurring. These areas where the pines are being removed will look bare for a while until the native replanted trees can develop.
By managing this infestation of giant pine scale, we continue to protect our important catchment forests and supply the community with a safe and reliable water supply, now and for generations to come.