Do Sydney and Canberra really need to choose between light rail and trees?

The Sydney Monorail as it was in 2012. It's since been pulled down to make way for a new light rail line. Image: Getty.

Looking out of the window on my morning bus journey from Kensington into Sydney’s central business district, I saw more trees being cut down to make way for the new light rail. This time, it was the historical fig trees that line Anzac Parade.

Trees like these provide a host of important ecological, environmental and aesthetic benefits. I – like many Sydneysiders – am deeply saddened by their loss. It leaves me wondering, why can’t we have a modern transport system but also enjoy a nice view along the way?

In meeting the needs of growing populations across our capital cities, it is vital that we have efficient, integrated public transport, with enough capacity to meet demand. The challenge of retrofitting transport systems into an established urban fabric means difficult decisions are inevitable. But what if building these new transport systems actually leaves parts of our cities more vulnerable to even bigger challenges, such as climate change?

Sydney and Canberra are forging ahead with light rail projects intended to reduce traffic congestion and improve accessibility. However, in both cities a significant number of mature trees will be impacted.

In Canberra, the ACT government is set to remove approximately 860 trees. In Sydney, about 1277 mature trees will either be removed or have their canopy or roots pruned.

Of the condemned trees, 871 are classified as trees of significant value. These trees, some of which were 160 years old, provide an array of benefits that make our cities liveable. These include clean air, amenity, biodiversity and cooling in hot temperatures.

The tree felling has has caused outrage among Sydney residents who are frustrated by the way planning decisions were made. A controversial amendment to the route to accommodate private commercial interests meant many trees were removed at the end of 2015.

Cutting down cities' natural cooling system

Many places in Australia are going to become hotter with climate change. The number of extreme heat days over 35 degrees is projected to increase.

The impact will be greater in cities due to the “heat island effect”. This amplifies the impacts of heat due to the abundance of hard and dark surfaces.

Extreme heat days in Australian cities. Source: BoM 2013b, CSIRO and BOM (author provided).

The table above shows that, by 2070, heatwaves are projected to nearly double the long-term average in both Sydney and Canberra. This is significant as major heatwaves are Australia’s deadliest natural hazard. Extreme heat accounts for 55 per cent more deaths than all other natural hazards combined.

A recent study showed that heat stress on the workforce costs the Australian economy US$6.2bn a year due to absenteeism, reduced productivity and injuries. This is a problem that has become too big to ignore.

However, increasing the amount of green cover in urban areas can help us adapt to extreme heat. Urban street trees provide the only cost-effective way to cool our cities, due to the direct correlation between heat and tree canopy cover.

Trees create their own microclimates through a combination of shading and the evapotranspiration of water from leaves, which reduces ambient temperatures. Removing canopy trees today means those cooling benefits will be gone for at least another 20 years – and that is only if new plantings survive to maturity.

The federal government recently announced plans for decade-by-decade goals – out to 2060 – for increasing overall tree coverage in our cities. Internationally, cities such as Madrid, which regularly experiences temperatures over 30 degrees and extremes above 40 degrees in summer, are starting to see the serious health implications of heat islands. These cities are implementing bold strategies to increase urban tree cover.

It is clear that to adapt to a hotter climate, we need to retain as many trees as possible. Australia needs to set strong targets to increase urban tree cover.

It could have been a very different outcome in Sydney if the value of the trees had been considered equally in the planning decisions. We could have had a modern transport system and valuable and attractive tree-lined view to enhance the journey.

As someone who works in the area of climate change adaptation, I can see how the loss of these trees will have major environmental, economic and social consequences. As a local resident who has walked and cycled daily under the trees, the loss has a personal cost.

It is imperative that we find better ways to balance the needs of growing city populations, while ensuring the protection of the natural environment we ultimately rely on to survive.The Conversation

Louise Boronyak is a senior research consultant at the University of Technology Sydney.

This article was originally published on The Conversation. Read the original article.


Coming soon: CityMetric will relaunch as City Monitor, a new publication dedicated to the future of cities

Coming soon!

Later this month, CityMetric will be relaunching with an entirely new look and identity, as well as an expanded editorial mission. We’ll become City Monitor, a name that reflects both a ramping up of our ambitions as well as our membership in a network of like-minded publications coming soon from New Statesman Media Group. We can’t wait to share the new website with you, but in the meantime, here’s what CityMetric readers should know about what to expect from this exciting transition.  

Regular CityMetric readers may have already noticed a few changes around here since the spring. CityMetric’s beloved founding editor, Jonn Elledge, has moved on to some new adventures, and a new team has formed to take the site into the future. It’s led by yours truly – I’m Sommer Mathis, the editor-in-chief of City Monitor. Hello!

My background includes having served as the founding editor of CityLab, editor-in-chief of Atlas Obscura, and editor-in-chief of DCist, a local news publication in the District of Columbia. I’ve been reporting on and writing about cities in one way or another for the past 15 years. To me, there is no more important story in the world right now than how cities are changing and adapting to an increasingly challenging global landscape. The majority of the world’s population lives in cities, and if we’re ever going to be able to tackle the most pressing issues currently facing our planet – the climate emergency, rising inequality, the Covid-19 pandemic ­­­– cities are going to have to lead the way.

That’s why City Monitor is going to be a global publication dedicated to the future of cities everywhere – not just in the UK (nor for that matter just in the US, where I live). Our mission will be to help our readers, many of whom are in leadership positions around the globe, navigate how cities are changing and discover what’s next in the world of urban policy. We’ll do that through original reporting, expert opinion and most crucially, a data-driven approach that emphasises evidence and rigorous analysis. We want to arm local decision-makers and those they work in concert with – whether that’s elected officials, bureaucratic leaders, policy advocates, neighbourhood activists, academics and researchers, entrepreneurs, or plain-old engaged citizens – with real insights and potential answers to tough problems. Subjects we’ll cover include transportation, infrastructure, housing, urban design, public safety, the environment, the economy, and much more.

The City Monitor team is made up of some of the most experienced urban policy journalists in the world. Our managing editor is Adam Sneed, also a CityLab alum where he served as a senior associate editor. Before that he was a technology reporter at Politico. Allison Arieff is City Monitor’s senior editor. She was previously editorial director of the urban planning and policy think tank SPUR, as well as a contributing columnist for The New York Times. Staff writer Jake Blumgart most recently covered development, housing, and politics for WHYY, the local public radio station in Philadelphia. And our data reporter is Alexandra Kanik, whose previous roles include data reporting for Louisville Public Media in Kentucky and PublicSource in Pittsburgh, Pennsylvania.

Our team will continue to grow in the coming weeks, and we’ll also be collaborating closely with our editorial colleagues across New Statesman Media Group. In fact, we’re launching a whole network of new publications this fall, covering topics such as the clean energy transition, foreign direct investment, technology, banks and more. Many of these sectors will frequently overlap with our cities coverage, and a key part of our plan is make the most of the expertise that all of these newsrooms combined will bring to bear on our journalism.

City Monitor will go live later this month. In the meantime, please visit to sign up for our forthcoming email newsletter.

As for CityMetric, some of its archives have already been moved over to the new website, and the rest will follow not long after. If you’re looking for a favourite piece from CityMetric’s past, for a time you’ll still be able to find it here, but before long the whole archive will move over to City Monitor.

On behalf of the City Monitor team, I’m thrilled to invite you to come along for the ride at our forthcoming digs. You can already follow City Monitor on LinkedIn, and on Twitter, sign up or keep following our existing account, which will switch over to our new name shortly. If you’re interested in learning more about the potential for a commercial partnership with City Monitor, please get in touch with our director of partnerships, Joe Maughan.

I want to thank and congratulate Jonn Elledge on a brilliant run. Everything we do from here on out will be building on the legacy of his work, and the community that he built here at CityMetric. Cheers, Jonn!

In the meantime, stay tuned, and thank you from all of us for being a loyal CityMetric reader. We couldn’t have done any of this without you.

Sommer Mathis is editor-in-chief of City Monitor.