Engineered Spaces for Trees in Paved Areas

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.