The City of Unley has been working over the last three years to develop an offset scheme to increase tree canopy on private properties, after setting a goal in 2020 to reach 31 per cent overall canopy by 2045.

The inner-suburban council area, which is 80 per cent private land, has long struggled with dwindling tree canopy due to urban infill. One council study in 2018 estimated Unley’s canopy coverage on private land declined from 34 per cent in 1979 to 22 per cent in 2017.

A net increase of 14,000 trees – 11,000 on private land on 3000 on council land – is required to reach the 2045 target, council estimates.

Unley mayor Michael Hewitson submitted a proposal to the former Marshall Government in October 2020 for a tree offset scheme that would assess new development applications against a minimum 15 per cent tree canopy target.

If the tree canopy minimum was not met, the property owner would be charged an extra 10 per cent on their council rates until they reach the target. The additional money would be put into a fund for the council to buy more land to plant trees.

The proposed scheme would apply to all new developments in the City of Unley that result in an “increase to the built footprint” – such as building two dwellings on one allotment or constructing a garage or swimming pool – but would not apply retrospectively to existing properties.

Hewitson resubmitted the council’s proposal to Labor Planning Minister Nick Champion on May 13 seeking support to begin a consultation period ahead of implementing the scheme in 2023.

But Champion wrote back on November 9 indicating he was “not inclined to support” the proposed scheme in its current form, citing advice it would be difficult to implement and measure.

“I have received initial advice from Planning and Land Use Services (PLUS) that a tree off-set scheme as proposed by the Council may be possible from a legislative perspective,” Champion wrote.

“However, a scheme requiring contributions to be paid until a specified threshold of tree canopy is reached may be difficult to implement and may also give rise to risks in the ongoing operation and management of the scheme.

“In particular, I am advised that there is a need to provide for contributions which are clear and quantifiable as well as fair and reasonable.

“An ongoing contribution which may be payable on an annual basis indefinitely (subject to tree canopy measurements, which may also be difficult to quantify) is not sufficiently clear and quantifiable.”

Due to provisions in the Planning, Development and Infrastructure Act 2016, the Planning Minister’s approval is required for council to progress implementation of any tree offset scheme.

Champion indicated he would be open to exploring a revised proposal.

“I am open to examining the proposal for an off-set scheme but only as a one-off payment arrangement,” he wrote.

“I am not inclined to support a scheme that requires ongoing payments, or payments which could potentially occur indefinitely.”

The City of Unley declined to comment on the Planning Minister’s position.

In his letter to Champion in May, Hewitson said the City of Unley could only address its tree canopy problem by reducing tree losses on private land.

The Unley mayor said between 2018 and 2021 council processed 1297 new development applications, of which 636 resulted in a decrease in canopy cover – equating to a loss of around 1250 trees.

“If canopy cover loss is to be addressed, the solution must include new developments,” Hewitson wrote.

“Furthermore, changes to the current planning legislation are required to address this problem or approval from the Minister for Planning.”

He also criticised the lack of provisions in the planning code for ensuring 15 per cent tree canopy.

“The current planning code makes provision for sufficient ‘soft soil’ to enable all developments to grow 15 per cent tree canopy cover should they choose to do so.

“The Code has no way of ensuring the soil available for planting will ever be planted with a tree that is allowed to grow.

“As it stands, there are no incentives to ensure that plantings occur and are retained.”

In his response to Hewitson, Champion highlighted that both the Planning Act and Code are under review by an expert panel, with tree policy within the scope of the inquiry.

“The Expert Panel’s review will consider the effectiveness of tree policy in the Code, being policy which is intended to facilitate both protection of existing trees as well as planting of new trees,” the Planning Minister wrote.

“I expect the Expert Panel will consider a range of approaches to improving tree canopy protections, which I hope will provide opportunity for a consistent and robust approach to be broadly implemented across the state.”

In a statement to InDaily, Champion said the expert panel would consider the City of Unley’s proposed tree offset scheme as part of its deliberations.

“We recognise the impact tree loss has on the community and welcome the City of Unley’s advocacy on this issue,” he said.

“I have commissioned an independent panel of planning experts to review key areas of tree regulations and the Council’s proposed model is being considered as part of this process.

“The Expert Panel will also consider other Australian jurisdictions’ tree policies, impacts of climate change and native replacements, and the regulations and definitions of trees to encourage more planting and tree retention as our city and state grows.

“Their review coincides with the State Planning Commission’s ongoing work into significant and regulated tree protections.”