Green infrastructure insights and discoveries

17 November 2018

How can we help urban trees to use valuable stormwater? What type of shrubs best handle Australian droughts? We’re excited to share these discoveries, and more, with you in our latest publications.

Tree water-use strategies to improve stormwater retention performance of biofiltration systems.

Chris Szota and colleagues are looking at how trees can improve stormwater retention in urban biofiltration systems. They have identified species that:

  • have high transpiration, so they are good at using stormwater
  • can cope with drying substrates by reducing evapotranspiration.

Their approach for identifying different tree water use strategies will assist in selecting species for biofiltration systems.  Water Res (2018) 144: 285-295.

Relationships between plant drought response, traits, and climate of origin for green roof plant selection.

PhD student Pengzhen Du has been investigating water use and drought tolerance of shrub species from a range of climates for green roofs. Ideally, green roof species should have high water use after rainfall to maximise stormwater retention, but also survive periods with low water availability in dry substrates.

In this study, species that had high water use were not found to be very drought tolerant. Selecting shrub species based on plant traits, rather than climate of origin, is likely to result in better green roof performance. Ecol. Apps. (2018) 28:1752-1761

Effects of deep tillage and municipal green waste compost amendments on soil properties and tree growth in compacted urban soils.

To increase the tree canopy cover in dense urban landscapes, developers, planners and urban tree managers are often forced to plant into damaged and compacted sites.

As part of his PhD, Peter Somerville has looked at different soil remediation strategies, including ripping (tillage) and adding green waste compost, and how this can help tree establishment and growth in compacted urban soils. J. Env. Man. (2018) 227:365-374.

Influence of plant composition and water use strategies on green roof stormwater retention.

In her recent PhD confirmation seminar, Zheng Zhang described how plant traits and substrate depth can influence rainfall retention on green roofs in Melbourne’s climate.

Zheng found that increasing substrate depth did not significantly improve green roof retention. But it had positive effects on reducing the irrigation needs of plants with greater water requirements.

Her findings suggest that plant selection for green roof rainfall retention should consider both water use strategies and root traits. Sci. Total Environ. (2018) 625:775-781

Find out more about our research.