No shade: why the North Shore is losing its trees

The North Shore is losing its trees when it needs them most.

Local councils have reported losses to their tree canopy coverage in recent years, and despite efforts to combat this, new planning regulations imposed by the New South Wales Government may be worsening the problem, an urban planning expert claims.

What is happening?

Ku-ring-gai Council — which represents an area known as Sydney’s “green heart” — will soon face new planning regulations allowing for subdivision on blocks of land as small as 450 square metres.

The policy aims to increase housing supply across the state, and the North Shore is expected to carry its load. 

Extra housing will come in the form of freestanding homes, villas, townhouses, duplexes and multi-storey apartment blocks. The drive to get more smaller properties onto blocks that once housed a single residence — the so-called “missing middle” — is causing councillors and experts significant concern over the future of the North Shore’s tree canopy.

This is because a small villa development on a block that once housed a single residence, for example, may require the removal of longstanding trees. 

Compared to other local government areas (LGAs) the upper North Shore has a high level of tree canopy coverage, which helps in the reduction of urban heat. In Ku-ring-gai the tree canopy coverage is 43.8 percent, and in Hornsby it is 42.5 percent.

An LGA’s urban canopy is determined via aerial imagery, and does not include non-urban areas such as national parks. 

With the effects of climate change predicted to worsen urban heat in Australia, the role of trees in helping to cool our suburban environment will become ever more crucial.

But the numbers are going the wrong way. In a 2022 survey by Ku-ring-gai Council, urban canopy was found to have shrunk by 1.4 percent over a period of two years. In response the council implemented a strategy aiming to increase the figure to 49 percent by 2036. 

Ku-ring-gai councillor Matthew Devlin says the state planning regulations are making it more difficult to reach tree canopy targets.

Just plant more?

Nearly 75 percent of Ku-ring-gai’s 286,000 trees are on private property in front and backyards, and council has no remit to force owners to plant more trees to help it meet canopy targets.

The shade trees provide in urban and suburban areas is crucial to preventing the urban heat island effect: a phenomenon in which materials like concrete and asphalt absorb and radiate the sun’s rays, generating sweltering microclimates in our suburbs.

What does it look like?

In NSW, it is illegal to cut down most trees, even if they are in your backyard. Typically, to remove a tree on private property, a permit must be sought from the local council. However, according to Devlin, there are a variety of ways in which people can circumvent these environmental protections.

Sometimes this manifests through criminal acts, such as purposefully poisoning or damaging a tree, leaving a council with no choice but to remove it as a safety hazard. 

Legal methods are available too. Devlin also told the Lorikeet of cases in which council rejected the removal of native trees, only for the applicant to instead seek approval from the state government. And then, “some bloke at an office somewhere who's never been to the LGA, [gives it] a big green tick”.

Richard Whitington lives in Turramurra and told the Lorikeet he was aware of native trees on plots being developed being damaged or killed.

What do the experts say?

Professor Sebastian Pfautsch shares Devlin's concerns, telling the Lorikeet “if these lots are now subdivided … the first thing that will happen is the disappearance of the large trees which give us the greatest canopy cover”.

“Across greater Sydney — even with millions of dollars being invested into tree planting programs for the different local governments — you still see a net decline in canopy cover because of what is happening on private land,” he said.

Pfautsch suggests that in a changing climate, with increasing urban heat, Sydney must build up and not out, promoting Barcelona as an example of smart urban planning in a subtropical climate.