Changes in nation’s greenspace revealed

SCIENTISTS HAVE answered the question, ‘Where should all the trees go?’ through a study that investigated vegetation change across major Australian metropolitan areas and locations with abnormally high heat, socio-economic disadvantage and health concerns.

Commissioned by Hort Innovation and led by RMIT University, the study involved the use of high-resolution aerial imagery and heat, health, age-risk and canopy data to formulate an index for each Local Government Area.

Hort Innovation chief executive John Lloyd said the research provided a canopy-cover health check to support the 202020Vision initiative – a collaboration which aims to increase green space by 20 per cent by 2020.

“This Where Should All the Trees Go study provides local councils, schools, developers and general members of the public a snapshot of the way their areas are tracking in the face of climate change and shifting urban environments,” he said.

“This new research also arms the nursery industry with a map to identify where certain plant species can have the most benefit, and make recommendations accordingly when approached for advice.”

Overall, the study found that greening had decreased by 2.6 per cent across Australia. Two consistent trends for tree canopy cover and total vegetation change also emerged.

Between 2009 and 2016, the nation experienced significant canopy cover loss, and this was largely offset by gains in shrub cover (or saplings) during the same period, representing a natural interchange between the canopy movement and shrubs.

To measure canopy cover, researchers utilised aerial imagery and a set of 1000 random sampling points generated within Local Government boundaries, collected between March 2016 and December 2016.

Additional data was collated to capture amalgamated council areas.

The urban heat island effect was estimated by measuring the difference in temperature between an urban and a corresponding non-urban area.

Land surface temperature estimates were produced from satellite data that passed over each location approximately every two weeks during October 2015 and April 2016.

A liveability index was then created using data such as canopy percentage versus hotspot percentage, and 2011 ABS data including the Self-Assessed Health Age Standardisation Rates and Socio-Economic Indexes for Areas.

See the Where Should All the Trees Go report.