4th May 2026
A new AI tool developed by University of Canterbury researchers has revealed where trees are being lost in the Garden City.
The study uses a combination of aerial imagery, LiDAR data and deep learning to detect and measure changes in urban tree canopy.
“Urban trees play a critical role in making cities more liveable,” PhD candidate David Pedley says.
“They help cool neighbourhoods, improve air quality and support wellbeing, but until now, it’s been difficult to track exactly where and why we’re losing them.”
Recent results show Christchurch lost about 14.5% of its urban tree canopy between 2016 and 2021. The majority of the loss occurred on residential land.
Pedley says the level of precision can identify tree loss at the scale of individual properties, which means more opportunities to better understand why trees are lost and how to effectively respond to that problem.
“If we want to maintain the benefits of urban trees, we need good data to inform our decisions,” says Professor Justin Morgenroth from UC’s School of Forestry. “This kind of insight can help guide planning, policy and investment to protect and grow urban forests where they are needed most.”
The Christchurch City Council (CCC) says urban trees are important because they deliver a wide range of environmental, social, and economic benefits across the city.
They help cool urban areas by providing shade and reducing heat, improve air quality, and support biodiversity by creating habitats for birds and other wildlife. Trees also play a key role in managing stormwater by slowing runoff and reducing pressure on drainage systems.
Beyond environmental functions, CCC notes how urban forests contribute to the wellbeing of residents by making neighbourhoods more attractive, improving public spaces, and supporting mental and physical health, while also adding long-term value to the city’s liveability and resilience.
Because Christchurch has lost a significant portion of its urban tree canopy, the very benefits CCC notes, such as cooling suburbs, managing stormwater, improving air quality and supporting wellbeing, are now being reduced in the places they’re needed most. This makes it more urgent to understand where trees are disappearing and how to protect or replace them.
The UC researchers say their approach could be applied in cities worldwide, using publicly available data to improve understanding of urban tree systems and inform more sustainable urban development.
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