Dr Paul Barber, President of Trillion Trees
Published in The Sunday Times - 8 June 2025
In a city where summer temperatures regularly soar above 40 degrees, trees are not a luxury, but essential infrastructure. I moved to Perth from Melbourne more than 20 years ago with my young family. I was struck by its natural beauty, liveability, and unique urban forest.
Sadly, Perth is losing one of its most vital assets: the tree canopy. If you believe the latest state government figures, it’s increasing. But the data tells a more complicated story.
Last week, after four years of waiting, the Western Australian Government released its updated Urban Tree Canopy data for 2024 — showing 22% total canopy cover for the Perth and Peel regions. That came as a surprise, especially since the 2020 figure increased from 16% to 21%.
How? Because the WA government has added four new land-use categories to the dataset: ‘Rural,’ ‘Water,’ ‘Other Infrastructure,’ and ‘Other.’ Including these non-urban areas may inflate the overall figure, and obscure the real losses in the canopy where most people live.
Digging into the State Government’s dashboard data, you’ll find councils like Fremantle and Bayswater have decreased their tree canopy, but not as much as Cottesloe, which lost 20% of its existing tree canopy in just four years. However, independent data suggests that these figures may not be accurate.
We should be asking: why are non-urban areas included in a measure of Urban Tree Canopy? If these areas are flagged for future development, then it's fine; we should understand what might be lost. But “gains” in undeveloped zones, where the canopy grows without pressure, risk masking the very real losses happening across our suburbs.
This matters because the canopy isn’t just about biodiversity or aesthetics — it’s a public health issue. Trees cool our streets, shield our homes from the heat, lower energy bills, and improve mental wellbeing. In a hot, dry city like Perth, shade can mean the difference between a tolerable summer and a dangerous one. For vulnerable people, the elderly, young children, and those without air-conditioning, it can be a matter of life and death.
Worse still, canopy loss isn’t evenly spread. Wealthier, older suburbs typically have greater access to mature trees, while in lower income and newer areas, green cover is removed to make room for higher density housing, roads, and hardscapes, simply doesn’t have sufficient space for trees to grow and mature. This creates environmental inequality: a heat gap, where some communities enjoy the benefits of a cooler, greener environment, while others are left exposed.
This is not just poor planning — it is a failure of government policy.
Canopy targets like the often quoted 30% sound impressive, but without binding commitments, transparent reporting, and regulatory enforcement, they’re just figures. Developments that remove mature trees continue to get the green light, while trees on public land are lost to infrastructure upgrades or neglected in budget decisions. Meanwhile, the state fails to collect or share accurate, consistent data on canopy loss and decline.
We need a better approach: one rooted in accountability, equity, and action.
First, tree canopy must be recognised as essential infrastructure, like roads or stormwater systems. That means investing in its protection throughout a tree’s life, not just at planting time. Residents shouldn’t have to fight to save local trees or beg for street shade. WA is a wealthy state. We can afford to prioritise tree canopy, greenspace, and community wellbeing if we choose to.
Second, transparency is critical. Other states, like NSW, release detailed, timely data separating urban and rural areas, within six months of acquisition. WA should do the same. This data should be mapped against heat vulnerability and socio-economic indicators to ensure that greening efforts are prioritised where they’re needed most.
Third, we must stop pretending that planting a sapling today offsets the removal of a 40-year-old tree. It doesn’t. Mature canopy provides exponentially greater cooling, carbon capture, and habitat — all of which takes decades to replace.
The good news? We know what works. Councils and cities across Australia and around the world are getting it right. But Perth must act quickly. With climate extremes already baked into our future, the window for action is closing fast.
Tree canopy is not just about trees. It is about people, places, and the kind of city we want to leave behind. Let’s not wait until the next heatwave or election to start demanding shade, transparency, and accountability.
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