Where Will All The Trees Be?

By Gabrielle Stannus

A new study funded by the nursery research and development levy continues earlier work benchmarking canopy cover in metropolitan local government areas. It also aims to highlight areas where increased consumption of green life products may be needed by governments and other consumers.

Published in 2014, Where Are All The Trees? was Australia’s first ever local government area (LGA) study of urban canopy cover. Using the i-Tree sampling method, researchers from the Institute for Sustainable Futures (ISF) at the University of Technology Sydney (UTS) analysed tree canopy cover in 139 Australian metropolitan LGAs.

In 2016, researchers from RMIT University continued this work through i-Tree, assessing changes to canopy cover in these LGAs. This time though, the researchers also examined the relationships between canopy cover and indices of socio-economic disadvantage (SEIFA), population under five years and over 65 years living alone, non-communicable disease health data from the Australian Health Survey (2011-12), and a calculation of heat island intensity derived from satellite imagery for summer 2015-2016. Using this data, the project team developed the VHHEDA (Vulnerability to Heat, poor Health, Economic Disadvantage and Access to green spaces) index.

The results of this second study were published in the 2017 guide, Where Should All the Trees Go? The researchers found two consistent trends for tree canopy cover and total vegetation change: canopy cover loss between 2009 and 2016, and offset by gains in shrub or sapling cover during the same period. The results were then used to identify priority areas for greening across Australia and to monitor progress towards the nursery industry’s then 202020 Vision goal of making Australia’s urban areas 20 per cent greener by the year 2020.

Where will all the trees be?

This important work has continued this year, supported by the nursery research and development levy through the “Where will all the trees be?” project (NY19001). This research continues to use the same methodology employed in the earlier studies to measure canopy cover across the LGAs sampled in 2014 and 2016, with one important difference.

“Whilst it once again benchmarks tree cover across the LGAs, this research also brings in other measures to forecast and determine what influences tree cover”, says Brendan O’Keeffe, an analyst with Hort Innovation, “This time, we are looking at the trajectories for urban forest cover under different scenarios that LGAs might have, e.g. policy or management.”