KALAMUNDA’s tree canopy data may become inflated as state government methodology changes have resulted in rural, water, and other areas now being counted in urban tree canopy data measurements.

Trillion Trees president Paul Barber said it was difficult to know with clarity what the methodology change meant for Kalamunda’s urban canopy data without having access to the changed boundaries.

“However, we can see a dramatic change in canopy cover in the state government’s urban tree canopy dashboard,” he said.

“Canopy cover dropped from 29 to 27 per cent from 2018 to 2020, but in 2024 increased to 34 per cent.

“I suspect this is due to changes in boundaries, so they are now including non-urban area in their figures.

“In an area like Kalamunda that probably includes a lot of rural and forested areas and can mask the real impact of urban development on canopy cover.

“It is important that figures are separated between urban and non-urban areas so we get access to data for each and can accurately monitor change over time.”

Kalamunda’s Nature Reserves Preservation Group (NRPG) member Steve Gates said the changes were likely to make it more difficult to accurately measure tree canopy in Kalamunda.

“There has been a change in methodology, and NRPG observes from the state government website (urban forest planning document) that they acknowledge the 2022 data and 2024 data are not comparable and have committed to address it.”

Mr Gates cited the section in the document which said the 2022 data would be retrospectively processed and published to address the data gap between 2022 and 2024 to allow direct comparison.

“The NRPG is willing to work with all parties to protect and enhance tree canopy across the City of Kalamunda, including residents, the city and development proponents,” he said.

“The NRPG is concerned about tree canopy losses due to development in the more highly vegetated areas around Gooseberry Hill, Kalamunda, Lesmurdie, Walliston, Bickley and Pickering Brook – a progressive Tree Canopy Protection Policy would help address these concerns.

Although Trillion Trees confirmed they did not have canopy cover data related to Kalamunda, they worked with the city to help increase canopy cover and have delivered their first plants for the residents program.

Dr Barber said the canopy data measurements warranted monitoring to ensure the state was on the right path as WA’s data processing was lagging behind its counterparts.

“It should not take four years to release data on the state of Perth’s canopy cover,” he said.

“In fact, it shouldn’t even take one year – others across the country are releasing data across larger areas in less time so we need to question why it takes so long.

“Are there concerns around the accuracy; are there concerns about the trend?

“We know from speaking to other local government areas throughout Perth and accessing independent canopy data that the story is not a good one.

“There are large losses of canopy in private land which are negating the gains in public land achieved through the planting and protection efforts by local government areas.”

Dr Barber said local governments typically had little to no control over trees on public land.

“The state’s policies and regulations have the greatest impact,” he said.

“Most local government areas will not achieve a 30 per cent canopy cover figure with a business-as-usual approach by the state.

“We need better policies and regulation, greater transparency, and access to granular and accurate data to understand what is really happening to our urban forest.

“I believe we should be keeping an eye on whether the inclusion of rural land in the urban tree canopy figures raises the possibility of the state pushing for large plantings on rural land to artificially inflate urban canopy figures to try and achieve a 30 per cent canopy figure.

“Although we should always encourage the planting of trees, whether on rural or urban land, we should be wary of such offsetting, as the greatest benefits to the well-being of people in urban areas are achieved through the protection and planting of trees in true urban areas.

“Such offsetting could pave the way for greater urban development and loss of existing trees.”