Removal of introduced Casuarina trees on South Perth Foreshore

As part of the Waterbird Refuge project on South Perth Foreshore, east of Coode Street, two groves of introduced, self-seeded Casuarina cunninghamiana are being removed to prevent further spread of these invasive weed.

The trees will be replaced with local species and the City has grown approximately 11,000 native plants, and 20 trees in its nursery for the project.

The existing Casuarina cunninghamiana trees that are being removed are considered weeds as they are not native to Western Australia and they spread their seed along the riverbank.

Our project partner, the Department of Biodiversity, Conservation and Attractions has recommended local native trees and understorey species are planted in the project area. Native foreshore vegetation is valuable as it provides multiple benefits; helps cool our river recreational areas by 3 - 5ºC, reduces erosion and helps stabilise foreshores, enhances liveability by creating natural wind breaks along the river foreshore, provides vital habitat for insects, birds and other native wildlife and improves water quality by slowing and filtering runoff before it enters drains and the rivers.

Casuarina cunninghamiana trees are endemic to the Northern Territory, Queensland and New South Wales. They are noted for their invasive roots and tendency to sucker creating many more specimens, as could be witnessed with these groves. While the City does not normally remove mature trees, it is considered appropriate to do so in this case, particularly along the river edge.

Removal of the trees will prevent further weed infestations along the river and enable replacement of damaged underground drainage pipes which are located under the Casuarina cunninghamiana groves. These drainage pipes provide a supply of freshwater to the Swan River from the lakes. Freshwater inputs are essential to support black swans and other birds on the river. Over time the drainage pipes have been damaged by the dense root mat of the Casuarina cunninghamiana trees and removal of these trees will allow the pipework to be reinstated. New trees will be located away from the pipes to prevent future damage.

The Waterbird Refuge project aims to protect the foreshore reserve, improve habitat for native waterbirds and protect the riverbank from erosion. Additionally, the project will replace damaged river walls with a habitat island, two vegetated headlands, a beach and a planted rock revetment.

The City successfully secured funding from the Department of Biodiversity, Conservation and Attractions Riverbank Program to support the Waterbird Refuge, and in July 2020, Council allocated municipal funds to the project.

The tree removal was publicly advertised in July 2020 and again recently on 28 January 2021 on the City’s website. Additionally, signs were in place on the South Perth Foreshore advising that the trees would be removed.

The project has grown from the City’s South Perth Foreshore Strategy and Management Plan (SPF Plan) which identifies Node 7: The Lakes as an area to be developed as a water-based, ecologically focused precinct, restored, expanded and integrated into its surroundings, and as a location to be developed for bird breeding.

The SPF Plan aims to balance the competing demands for use, development and management of this precious regional reserve with the need to conserve and enhance a functional healthy river and foreshore environment.

The City has engaged extensively with the community and stakeholders on the development of the SPF Plan to improve the amenity, access and sustainability of the reserve.

The City of South Perth is home to nearly 400 hectares of urban forest on private and public land, there are over 100 hectares of natural areas with significant tree cover in the City.

The City manages and monitors over 26,000 trees on bushland and foreshore environmental reserves as well as an unidentified number of shrubs. A dedicated tree planting scheme has seen the City of South Perth’s canopy cover remain consistent over the last 30 years.

City of South Perth Chief Executive Officer

Mike Bradford