National award for mapping tree canopy change
Published on 24 June 2022
The digital project accurately measures and monitors changes in tree canopy coverage over time across the Unley council's areas – its suburbs and streets, down to individual properties.
The process of trying to accurately quantify tree cover was previously labour intensive, with Council staff manually applying grid-based measurements to aerial photographs to understand change – a process which took months and had a high rate of error.
But with a pledge to increase canopy coverage by up to 20 percent by 2045, Council was keen to better understand how its various tree policies and planting programs were affecting growth.
Developed in partnership with local geospatial technology company Aerometrex, the digital approach uses LiDAR data, captured in aerial surveys in 2018 and 2021, to compare changes over this three-year period.
Council collaborated with aerial survey company Aerometrex, who developed a system to classify canopy changes as either tree planting, tree growth, tree removal and/or tree pruning.
Council staff then mapped out the changes at the property level and overlaid the canopy maps with boundary layers, development and building information, and tree maintenance data.
Using the ‘digital twin’, the council was able to determine that its tree canopy coverage increased 1.36 percent between 2018 and 2021 (from 26.63% to 27.99%).
It showed that tree canopy loss on private land is two to three times higher than it is on council land, and that growth of existing trees contributed five times as much new canopy cover than newly planted ones.
Information from the digital technology is also being used to educate ratepayers, with rates notices sent to most residents including details about their property’s percentage of canopy coverage.
Unley collaborated further to develop the project, working with an Adelaide tree management provider on an app that allows our community to visualise changes on their properties over time.
Learn more about Unley’s MyCanopy app project alongside the other award finalists.
The image shows Unley Business Intelligence Analyst Stephen Yates and Environmental Strategy Coordinator Kat Ryan (at centre) receiving the award.