The role of street trees in addressing liveability inequity

Streets are critical infrastructure that have an enormous impact on the liveability of a city. In a physical analogy, streets provide the circulatory system of living urban systems connecting people to a range of different places, and provide a similar role to the important arteries, veins and capillaries within our living bodies. They are important for enabling mobility and movement using all types of transport modes, provide opportunities for social connection and community interactions, and support the provision of cooling green infrastructure like street trees and vegetation that is good for health and biodiversity in our cities.

Streets are also a key ingredient of walkable neighbourhoods connecting people to local destinations and services providing the foundation for liveable places. People need local destinations to make walking, cycling and active transport methods viable which provide the foundations of healthy, sustainable and liveable places. The design and use of local streets needs to be refocused and move beyond roads for cars and mass transport and concentrate more on walking, cycling and public transport as well as including urban greening into the urban design conversation.

Defining and measuring liveability

Most public commentary on liveability has connotations of marketing and attracting people to live, work or play in an area. These kinds of conversations about cities and places tend to refer to ‘liveability’ as an abstract concept that is hard to define and not clearly understood.

In the Australian Urban Observatory we are guided by a clear definition of liveable places as places that:

• Are safe
• Are attractive
• Are inclusive
• Are environmentally sustainable
• Have diverse and affordable housing
• Are supported by walking and cycling infrastructure
• Provide access to frequent public transport
• Connect people to public open space, local shops, community services, employment, education, leisure and cultural opportunities.

These are what we have described as the key ingredients of a liveable city which are really necessary if we want to design cities that support health and wellbeing.

All of these key ingredients of liveability are directly influenced by the planning and design of our cities and aligned with improved social determinants of health. Most people think of health in terms of illness and disease, but social determinants describe the socioeconomic and political factors outside of the health system that influence health and wellbeing. The conditions where people are born, live, learn, work, play and age all affect long-term health outcomes and are very much under the influence of planning and design. Consequently, liveability provides an easy way to describe the relationship between public health and urban planning.

However, not everyone across a city shares the same experience of liveability; there is a widening gap in 'liveability inequity' – avoidable and unfair differences in liveability – that is increasing depending on where people live. This liveability inequity of the ‘haves and have nots’ has also been magnified in cities that have been locked down to local neighbourhoods during the COVID pandemic.

An investigation of Liveability Index results across Melbourne reveals stark differences in overall liveability of suburbs across Melbourne [1]. As shown in Figure 1, inner suburbs have higher levels of liveability in comparison to suburbs of the outer growth areas of the city. These outer areas include ever-expanding, low density developments without the local services, social infrastructure, public transport and walkability of many inner area suburbs, but are often attractive for residents seeking more affordable housing options.

However, not all neighbourhoods of outer growth area suburbs have lower levels of liveability. Figure 2 shows high levels of liveability in small area neighbourhoods across the growth area suburbs of outer north-western Melbourne. Good planning and design can create very liveable areas in most suburbs. This reinforces the importance of investigating liveability at the local scale and not just at larger scale regional or municipal levels.

Understanding and identifying where liveability inequities exist is necessary for directing future interventions to lift surrounding neighbourhoods and improve local liveability for everyone and not just the people who can afford to live in existing liveable neighbourhoods. Instead of investing further in areas with high levels of liveability, better value could be achieved by investing in action to improve the liveability of areas that really need it.

These maps also emphasise the link between liveability and current patterns of urban development in sprawling outer growth areas. Often new urban developments in these areas are based on principles of low density but feature poor urban design, unsustainable housing (including black roofs and poor energy conservation in new urban developments), and the need for a private vehicle to access schools, employment, shops and services.

A nature-based solution for addressing liveability inequity

Street trees and urban forestry provide a great example of a ‘nature-based solution’ to building environmentally sustainable liveable cities that provide multiple benefits. This urban greening provides inviting and nice places to walk, shade and adaptive responses to climate change, UV protection from the sun, ecosystem services and local habitats to support urban biodiversity so that both people and nature can both flourish.

However, despite all the well known benefits of street trees, there are inherent inequities in both their distribution and how people make decisions about them. For instance, street trees are inequitably distributed across cities and link urban forestry inequity with liveability inequity [2]. Disadvantaged communities in cities, characterized by lower level of income and education, and, in some cases, higher percentages of minority populations, tend to have less street tree cover and less street tree diversity. Planting street trees in treeless areas rather than in already leafy suburbs has a greater effect on reducing extreme heat, increasing biodiversity, and reducing health inequalities.

This inequity can be further compounded when disadvantaged communities are not integrated into decision-making about street trees. The evidence base for how the community values street trees rarely includes diverse perspectives – particularly people from different cultural backgrounds, or Indigenous people – with diverse views. This is important because understanding how urban communities perceive street trees and urban forests is necessary so that urban planners, managers, and designers can better incorporate diverse views and community needs into local decision making. In our research, we’ve found that practitioners who make decisions about these matters value community views, such as people’s sense of stewardship of their street trees and urban forests, however, it can be difficult to combine these views with cross departmental planning in organisations that are fearful of risk [3].

Also, typical community engagement processes tend to favour more advantaged sections of the community – the educated and affluent. Carefully targeted engagement with culturally diverse communities, students, renters and Indigenous communities is needed to overcome the ‘procedural inequity’ found in the standard business-as-usual community engagement approaches.

Addressing liveability inequity by improving the most disadvantaged and least liveable neighbourhoods has many benefits that can improve the life outcomes of all people no matter where they live. It can also help avoid one of the perils of improving liveability; gentrification and the displacement of disadvantaged communities [4]. Improving the way we think about, design and plan our streets and neighbourhoods to address the inequitable distribution of street trees and urban forestry is an important part of creating more environmentally sustainable and liveable cities.