Published on 10 April 2024

New study shows Onkaparinga tree canopy increase

Tree canopy in the City of Onkaparinga increased by four per cent between 2018–2022 according to data released by Green Adelaide this week.

The study, led by Green Adelaide, is the first time state and local government have partnered to capture tree canopy data for the entire metropolitan Adelaide area in a single study.

Using LiDAR (light detection and ranging) technology, the study allowed Green Adelaide and 18 councils across Adelaide – including Onkaparinga – to compare new 2022 data with a similar survey from 2018–19.

It showed about 17 per cent of metropolitan Adelaide – and 20 per cent of the City of Onkaparinga – is currently covered in tree canopy, with both having seen increases of about four per cent since 2018–19.

Tree canopy – the number and size of trees – is important because it provides shade, cooling, clean air, less stormwater runoff, habitat for birds and wildlife, and reduction in climate change impacts, ultimately improving the wellbeing of individuals, communities and the environment.

City of Onkaparinga Mayor Moira Were said while any increase was great news, there’s still a lot of work to do to increase Onkaparinga’s tree canopy to a desired level and spread equitably across the region.

“It’s pleasing to see efforts to reverse the decline in our tree canopy are working, but there’s plenty more work to be done,” she said.

“As Green Adelaide Presiding Member, Professor Chris Daniels, notes – 30 per cent tree canopy cover is a widely accepted target for urban areas.

“While Onkaparinga’s total council area is now at about 20 per cent cover, we know our urban areas – particularly along our coast – have less than that, and the difference in canopy can vary greatly depending on the suburb.

“The new data is important for helping us see where to better focus our tree planting efforts, particularly as we’re currently reviewing our tree canopy cover target for urban areas.”

The new study found the increase in tree canopy cover in metropolitan Adelaide, including Onkaparinga, was primarily due to the growth of existing larger trees, which have now reached three or more metres in height.

“They’re considered valuable at this height because this is when they begin to provide shading and cooling benefits to the surrounding area,” said Professor Daniels.

The increase in tree canopy cover in Onkaparinga since 2018 was most pronounced on local and state government land, with increases of six and eight per cent respectively.

Onkaparinga Council has planted more than 56,000 trees on street verges, alongside waterways and in parks since 2017 in its quest to plant 100,000 trees by 2037, with many of these plantings set to add to the region’s canopy cover when they reach three metres in the coming years.

The council uses aerial heat and canopy mapping to prioritise where to plant through its Suburb Improvement Program, while also managing more than 270 conservation sites and supporting volunteering activities, including planting activities at 44 reserves.

The new Green Adelaide study showed a more modest four per cent increase in the tree canopy on private land, which makes up the bulk of Onkaparinga’s total area (74 per cent).

That’s why Mayor Were said encouraging planting and retaining trees on private land also continues to be a focus of the council.

“We’ve been advocating to the state government about better planning laws to protect trees, and later this month we’ll be launching a new campaign to encourage each child in the area plant at least one tree before leaving school,” she said.

“These efforts add to our long history of work around community education, encouraging the planting, care and retention of trees on public and private land.”

Other council programs under its “Trees are Cool” education banner include ongoing sustainability workshops, an Adopt a Tree program, a seed library at Woodcroft Library, new verge guidelines and display verges, tree tags and trails, and a Tree of the Month campaign.

You can find out more about trees in the City of Onkaparinga at onkaparingacity.com/trees

Pictured

Aldinga Scrub from above.