If there is one thing the pandemic of the past two years has taught us, it is how people value their green and natural spaces, especially in our cities. During lockdowns we crowded our parks, riverbanks, walkways, and bike paths. Fresh air and greenery were an escape and a refuge from the virus.

This is not surprising given that ongoing research has shown how important trees and greenspaces are for human health and well-being. In cities, trees when combined with other vegetation and the soil and water, form what is known as an ‘urban forest’.

Urban forests provide us with areas for exercise, healing and pain relief. They reduce our stress and help us to feel more positive. Beyond delivering such physical and mental health benefits, urban forests build social cohesion from a sense of shared space and neighbourhood connection, which reduces crime and fear.

Research shows that urban forests have even further benefits. They provide us with ecosystem services through cooling and improved air quality. Large trees and accompanying vegetation reduce the heat felt in our streets and neighbourhoods. Trees also capture and filter air pollution.

Our wildlife benefit from urban forests, which provide them with habitat and shelter. Green corridors provide a means for animals, like koalas, to move more freely and safely across our urban landscapes.

Urban planners are becoming more and more conscious of the benefits of urban forests. However, planning and maintaining urban forests is not just about planting a big park full of trees.

Creating the space for urban forests needs to be equitable

In January 2020, Penrith in Western Sydney hit the hottest temperature ever recorded – 48.9^oC. Heat waves such as these cause far more death than bushfires and are set to become more common as our climate continues to change.

Flying above the Sydney Basin, it is obvious that Western Sydney has far fewer green patches covering it than more affluent parts of the city to the north, south and east. Research backs up such observations indicating that the leafier suburbs are the wealthier suburbs.

Access to green leafy spaces across many cities, including Sydney, is roughly proportional to household wealth. Many of Sydney’s lower income local government areas (LGA) lack green space buffers.

However, many of the suburbs in these areas such as Blacktown, Camden, Fairfield, Liverpool and Penrith actually have the bare areas available to create green spaces, unlike the City of Sydney LGA which has more bitumen and concrete. There are opportunities to invest in greening these LGAs and some councils are proactively trying to do just this, but more needs to be done.

Photographer: Brook Mitchell/Getty Images (www.bloomberg.com/news/features/2020-09-15/sydney-s-new-suburbs-get-so-hot-that-people-could-die-there)

In a vicious circle, people living in lower socio-economic areas are less able and likely to be vocal and proactive about the need to retain or grow green spaces compared to those from wealthier suburbs. They are also less likely to engage in policy issues which further compounds issues of greenspace inequities.

Such inequity is highlighted in the New South Wales Government’s ‘Greener Public Spaces Premier’s Priority’, which aims to “increase the proportion of homes in urban areas within 10 minutes walk of quality green, open and public space by 10% by 2023”.

The NSW Government has also set a target to increase tree canopy cover to 40% across Greater Sydney. Realising such a goal will require evidence-based understanding and planning. We need to understand the dynamics of tree loss, growth, maintenance and change across our urban landscapes. Such understanding is crucial if we are to plan and meet our targets meaningfully.

Stop the loss of existing urban trees

As our cities grow and expand, our trees and green areas are under constant threat. Development, vandalism, death of young trees, drought and vehicle damage all result in urban tree loss.

Increasing heat with climate change in our cities also affects our urban forests. More than one in 10 trees checked for canopy damage throughout the 2019-2020 summer heatwave that hit Penrith were heat damaged. The cost of replacing these damaged or dead trees was estimated to be $500,000-$800,000.

Often the greatest tree loss happens on privately-owned land. For example, in the North Sydney Council area the greatest loss of trees in recent years has been on private land, which makes up 58 per cent of the LGA.

This issue reflects a failure of governance about how decisions are made for sustainable urban forest outcomes. Such challenges will not be addressed just by providing bigger budgets, more people and having a management plan in place. There needs to be communication and coordination between departments, LGAs, communities and residents.

Start planning new urban forests by applying the 3-30-300 rule

Based on our experience in planning urban forests, we understand that each situation is different and has its complexities. Regardless, we believe the 3-30-300 rule  is a good place to start when thinking about urban forests.

• 3 trees from every home – which recognises the importance of nearby, especially visible, greenery for mental health and wellbeing
• 30% cent tree canopy cover in every neighbourhood – which is aligned with how urban forests can lead to cooling, better microclimates, mental and physical health, and possibly even a reduction in air pollution and noise (Canberra, like many other cities around the world, have set a target of achieving 30% canopy cover)
• 300 metres from the nearest park or green space – which highlights the results of many studies recognising the importance of proximity and easy access to high-quality green space that can be used for recreation