TREENET supports urban forest research with practical application to growing and managing healthy, long-lived trees in Australian towns and cities. Together with our network of supporters and research institutions we are active in three key areas:

Street Tree Species Trials

Street tree trials have been a fundamental part of TREENET since its inception in 1997.

Since it was discussed at TREENET's first symposium, the focus on tree species selection remains along with other factors which impact on the effective functioning of urban trees.

Growing healthy trees in urban streets where conflicts involving space, soil and water are usual is as much about planning for, building and managing urban spaces, as it is about selecting tree species.

Much has been written on tree species selection and related issues such as climate change and papers have been presented at past Symposia.

As TREENET was formed at the Waite Arboretum, it was inevitable that many of the original street tree trials focused on species planted there, which had proved themselves. Other trial species were contributed by the nursery industry.

Early trials included the Wilga (Geijera parviflora), Chinese pistachio (Pistachia chinensis) and Crows Ash (Flindersia australis).

Check out the following resources which have been extracted from TREENET's significant collection of academic papers and case studies:

Experiments and Education: The Roadway Ahead – Judy Fakes

Establishing TREENET Trial Sites
Street tree trials in the City of West Torrens
TREENET Trials 2009: A Species Odyssey

Water sensitive urban design (WSUD)

Water sensitive urban design (WSUD) emphasises a holistic approach to water management with the aim of achieving multiple objectives, including:

  • Protection of natural aquatic ecosystems
  • Integration of stormwater treatment into the landscape
  • Protection of water quality
  • Reduction of run-off and peak flows

Designers, civil engineers and urban forest managers alike are considering the advantages of applying onsite stormwater retention measures to defer capital expenditure on upgrades of existing drainage infrastructure and to optimise the benefits of trees in our towns and cities.

Permeable paving infiltrates stormwater into the road subgrade at the intersection of Kegworth and Wheaton Roads in Melrose Park, South Australia. As part of a broader treatment, this solution cost $1M less than the alternative option of upgrading the pit and pipe network.

The TREENET Inlet is an example of a WSUD device; it was designed to direct stormwater from roads into what is often the driest zone in the urban environment, the ‘nature strip'.
By providing water via soakage devices in the nature strip, TREENET Inlets may guide root growth to these zones and so reduce root damage to kerbs and footpaths, possibly resulting in financial savings on infrastructure maintenance and renewal.

Check out the following resources which have been extracted from TREENET's significant collection of academic papers and case studies:

An investigation of the potential to use street trees and designed soils to treat urban stormwater
Council Verges as the Next Wetland – The City of Salisbury and TREENET Working Together
Permeable Pavements and their Influence on Tree Growth of Melaleuca quinquenervia – A Summary
Trees and permeable paving: future symbionts

 

Engineered Spaces for Trees in Paved Areas

Urban trees and tree canopy cover are increasingly recognised as essential components of the cities and neighbourhoods where more than 90% of Australia's forecast population of 35 million will live by 2050.
International research and practice, to date, has responded to the challenge of sustaining multi-functional, large, long-lived trees within compact forms of development, amongst paved plazas and alongside roads and streets.

A range of techniques have been advanced that are capable of delivering adequate quality and quantity of space for tree root growth while maintaining pavement functionality, including: structural soil; soil filled load-bearing cells; suspended slab pavement along with permeable pavements.

Applications of these engineered surface and subsurface tree spaces in Australian cities has occurred over the last 20 years. However, their use has been limited, rarely monitored and is often perceived by developers, infrastructure authorities and local governments as a high cost, high-risk approach.

Yet these same stakeholders are increasingly attentive to the opportunities that green infrastructure components offer to community health and well-being, tourism, business vitality, property value improvement, place making, buffering urban microclimate, managing local stormwater, air quality improvement, and so much more.

This national study proposes a range of monitored, long-term trials in Australian cities to advance best practices and build knowledge sharing. Complementary qualitative research is also proposed to explore the barriers to implementation and to collate the learnings from existing installations of surface and subsurface tree spaces.

TREENET, as a reputable, independent non-profit organisation dedicated to improving the urban forest, sees facilitating this special research project as critical to building home-grown evidence to support those designing our cities for trees.

Permeable pavement excavations root penetrations (marked by the triangles) occupied a relatively small proportion of the exposed geotextile surface. A much larger area (shaded white) was devoid of root penetrations. The tree planting pit was to the lower right of the image.

In seeking to refine the scope and methodology of the ‘National Trials Project', develop cost estimates and source funding opportunities, TREENET is engaging with key stakeholder groups in order to progress best practice in designing and maintaining engineered spaces for tree growth in paved areas in Australian cities.

Interest continues to be sought from research organisations, industry associations, product manufacturers/distributors, product user groups (eg. local government, landscape architects, urban designers, construction companies) and potential trial site stakeholders.

 

Check out the following resources which have been extracted from TREENET's significant collection of academic papers and case studies:

Best practice design and implementation of urban tree planting – Victoria Avenue Pedestrian Mall upgrade, Chatswood NSW
Meeting the challenge of managing tree roots & infrastructure

Examples of existing experiences can be explored via the Case Studies Portal.