It’s not easy being a street tree, but this heroic eucalypt withstands everything we throw at it

by bpckle | Apr 4, 2025 | Media

Street trees usually grow in appalling soils, have little space for their roots, are rarely watered and often get aggressively trimmed by road authorities or utility companies.

If they do get established, many street trees suffer damage from vehicles, have to live in wind tunnels or are forced to grow in the permanent shade of large buildings.

But despite everything we throw at them, many street trees don’t just survive, they thrive. So let’s meet one of these heroic species: the yellow gum, (Eucalyptus leucoxylon).

Pretty but tough

Yellow gum is widely planted across southeastern and eastern Australia as a street tree. In some suburbs and towns, it is so common that people think it is a native tree (in fact it is from South Australia, Victoria or southwest New South Wales).

It is not to be confused with yellow box (Eucalyptus melliodora), a different eucalypt altogether.

Yellow gum has been widely planted because it meets many of the demands we place on urban trees.

It grows well in different soils and climates, and has very attractive red, white or pink flowers.

It’s called yellow gum in Victoria and parts of NSW, but is often known as blue gum in SA.

The common names can be confusing, but yellow gum refers to its pale yellow wood and bark patches, while blue gum refers to its leaves.

Many specimens develop dense, low, spreading canopies, which offer lovely shade and help cool our cities down.

And importantly, it doesn’t grow too big. It is typically a medium to small woodland tree, usually between 13 and 16 metres high (but it can grow higher in the wild).

Different bird and insect species feed on the trees some feeding on flowers and fruits and others on the foliage.

Natural populations of yellow gum occur in coastal and inland SA, in the southwest corner of NSW and in the western half of Victoria from the Murray River to the coast.

There are several subspecies, too, and debate rages in botanical and horticultural circles about whether some of them deserve to be recognised as their own species.

Yellow gum is also tolerant of wind and salt spray, and can withstand waterlogged soils. They stood up to the millennium drought conditions well.

Many arborists think the yellow gum has the potential to do well in many parts of Australia as the climate changes. Research has shown, for example, that some individual yellow gum trees regulate their water use better (when compared to other individuals in the species, and when compared to other eucalypts).

Like many eucalypts, yellow gum possesses lots of dormant buds and a lignotuber (a swelling at the base of the trunk containing dormant buds and carbohydrate). This means it copes well with pruning and will respond especially well to targeted formative pruning when young.

This can help reduce the risk of problems such as what’s known as “co-dominant stems” (when two main stems grow from a single point of origin, instead of one tall, straight trunk) and rubbing or crossing branches.

Not everyone’s favourite

Not everybody likes the yellow gum, and for some good reasons.

Some yellow gums are multi-stemmed, while others have twisted and curving trunks; some have both. These are not the characteristics many local governments want in street trees; many want to see straight trunks and dense canopies.

These problems can be so annoying that some council arborists no longer recommend planting yellow gums.

But these issues are due to poor tree selection and propagation. In the past, yellow gum seed was not carefully sourced from the best trees with the most suitable characteristics, and so inferior specimens have prospered.

With the right investment of time and money into tree selection, these problems can be overcome.

Ticking most of the boxes

All in all, yellow gum can be a very fine and useful urban tree.

The species grows well and if superior stock is used, the trees develop with straight and attractive trunks and wide, dense canopies.

They are typically medium-sized trees, do well in tough street conditions or in smaller domestic front and back yards.

They tick most, if not all, of the boxes for a good urban street tree.

Gregory Moore does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

This election, what are Labor and the Coalition offering on the energy transition, climate adaptation and emissions?

by bpckle | Apr 4, 2025 | Media

Australia’s 2022 federal election was seen as the climate election. But this time round, climate policy has so far taken a back seat as the major parties focus on cost-of-living issues.

Despite this, climate change remains an ever-present threat. Last year was the world’s hottest on record and extreme weather is lashing Queensland. But there are hints of progress. Australia’s emissions have begun to fall and the main power grid is now 40% renewable.

So before Australians head to the polls on May 3, it’s worth closely examining the climate policies of the two major parties. What are they offering on cutting emissions, preparing for climate-boosted disasters and future-proofing our energy systems? And where are the gaps?

Energy transition – Tony Wood, Grattan Institute

Cost-of-living pressures, escalating damage from climate change and global policy uncertainty mean no election issue is more important than transforming Australia’s economy to achieve net zero. But our energy supply must be reliable and affordable. What should the next government prioritise?

There is great pressure to deliver power bill relief. But the next government’s priority should be reducing how much a household spends on energy, rather than trying to bring down the price of electricity. Far better to give financial support for battery storage and better home insulation, to slash how much power consumers need to buy from the grid.

The Liberal-led Senate inquiry has just found supporting home electrification will also help with cost of living pressures.

The electricity rebates on offer from Labor and the temporary cut to fuel excise from the Coalition aren’t enough.

Federal and state governments must maintain their support and investment in the new transmission lines necessary to support new renewable generation and storage.

Labor needs to do more to meet its 2030 target of reaching 82% renewables in the main grid. Currently, the figure is around 40%. The Coalition’s plan to slow down renewables, keep coal going longer and burn more gas while pushing for a nuclear future carries alarmingly high risks on reliability, cost and environmental grounds.

Gas shortfalls are looming for Australia’s southeast in the next few winters and the price of gas remains stubbornly high. Labor does not yet have a workable solution to either issue, while the Coalition has an idea – more and therefore cheaper gas – but no clarity on how its plan to keep more gas for domestic use would work in practice.

So far, we have been offered superficially appealing ideas. The field is wide open for a leader to deliver a compelling vision and credible plan for Australia’s net-zero future.

Climate adaptation – Johanna Nalau, Griffith University

You would think adapting to climate change would be high on the election agenda. Southeast Queensland just weathered its first cyclone in 50 years, estimated to have caused A$1.2 billion in damage, while outback Queensland is enduring the worst flooding in 50 years.

But so far, there’s little to see on adaptation.

Both major parties have committed to building a weather radar in western Queensland, following local outcry. While welcome, it’s a knee-jerk response rather than good forward planning.

By 2060, damage from climate change will cost Australia $73 billion a year under a low emissions scenario, according to a Deloitte report. The next federal government should invest more in disaster preparation rather than throwing money at recovery. It’s cheaper, for one thing – longer term, there are significant savings by investing in more resilient infrastructure before damage occurs.

Being prepared requires having enough public servants in disaster management to do the work. The Coalition has promised to cut 41,000 jobs from the federal public service, and has not yet said where the cuts would be made.

While in office, Labor has been developing a National Adaptation Plan to shape preparations and a National Climate Risk Assessment to gather evidence of the main climate risks for Australia and ways to adapt.

Regardless of who takes power, these will be useful roadmaps to manage extreme weather, damage to agriculture and intensified droughts, floods and fires. Making sure climate-exposed groups such as farmers get necessary assistance to weather worse disasters, and manage new risks and challenges stemming from climate change, is not a partisan issue. Such plans will help direct investment towards adaptation methods that work at scale.

New National Science Priorities are helpful too, especially the focus on new technologies able to sustainably meet Australia’s food and water needs in a changing climate.

Emission reduction – Madeline Taylor, Macquarie University

Emission reduction has so far been a footnote for the major parties. In terms of the wider energy transition, both parties are expected to announce policies to encourage household battery uptake and there’s a bipartisan focus on speeding up energy planning approvals.

But there is a clear divide in where the major parties’ policies will lead Australia on its net-zero journey.

Labor’s policies largely continue its approach in government, including bringing more clean power and storage into the grid within the Capacity Investment Scheme and building new transmission lines under the Rewiring Australia Plan.

These policies are leading to lower emissions from the power sector. Last year, total emissions fell by 0.6%. Labor’s Future Made in Australia policies give incentives to produce critical minerals, green steel, and green manufacturing. Such policies should help Australia gain market share in the trade of low-carbon products.

From January 1 this year, Labor’s new laws require some large companies to disclose emissions from operations. This is positive, giving investors essential data to make decisions. From their second reporting period, companies will have to disclose Scope 3 emissions as well – those from their supply chains. The laws will cover some companies where measuring emissions upstream is incredibly tricky, including agriculture. Coalition senators issued a dissenting report pointing this out. The Coalition has now vowed to scrap these rules.

The Coalition has not committed to Labor’s target of cutting emissions 43% by 2030. Their flagship plan to go nuclear will likely mean pushing out emissions reduction goals given the likely 2040s completion timeframe for large-scale nuclear generation, unless small modular reactors become viable.

On gas, there’s virtually bipartisan support. The Coalition promise to reserve more gas for domestic use is a response to looming shortfalls on the east coast. Labor has also approved more coal and gas projects largely for export, though Australian coal and gas burned overseas aren’t counted domestically.

Opposition Leader Peter Dutton has promised to include gas in Labor’s renewable-oriented Capacity Investment Scheme and has floated relaxing the Safeguard Mechanism on heavy emitters. The Coalition has vowed to cancel plans for three offshore wind projects and are very critical of green hydrogen funding.

Both parties will likely introduce emission reduction measures, but a Coalition government would be less stringent. Scrapping corporate emissions reporting entirely would be a misstep, because accurate measurement of emissions are essential for attracting green investment and reducing climate risks.

Johanna Nalau has received funding from Australian Research Council for climate adaptation research, is a Lead Author of the Intergovernmental Panel on Climate Change, Co-chair of the Science Committee of the World Adaptation Science Program (United Nations Environment Programme) and is a technical expert with United Nations Framework Convention on Climate Change

Madeline Taylor has received funding from the Australian Research Council, ACOLA, and several industry and government partners for energy transition research. She is a board member of REAlliance, Fellow of the Climate Council, and Honorary Associate of the Sydney Environment Institute.

Tony Wood may own shares in companies in relevant industries through his superannuation fund

Good news, beach lovers: our research found 39% less plastic waste around Australian coastal cities than a decade ago

by bpckle | Apr 3, 2025 | Media

Picture this: you’re lounging on a beautiful beach, soaking up the sun and listening to the soothing sound of the waves. You run your hands through the warm sand, only to find a cigarette butt. Gross, right?

This disturbing scene is typical of coastal pollution in Australia. But fortunately our new research shows the problem is getting better, not worse. Over the past ten years, the amount of waste across Australian coastal cities has reduced by almost 40%. We’re also finding more places with no rubbish at all.

We surveyed for debris in and around six Australian urban areas between 2022 and 2024. Then we compared our results to previous surveys carried out a decade ago. We found less coastal pollution overall and reset a new baseline for further research.

Our study shows efforts to clean up Australia’s beaches have been working. These policies, practices and outreach campaigns have reduced the extent of pollution in coastal habitats near urban centres. But we can’t become complacent. There’s plenty of work still to be done.

What we did

In Australia, three-quarters of the rubbish on our coasts is plastic. Even cigarette butts are mainly made of plastic.

To tackle the pollution effectively, we need to understand where the waste is coming from and how it gets into the environment.

Research has shown much of the coastal debris comes from local inland areas. Poor waste management practices can result in debris eventually making its way through rivers to the coast and out to sea.

We focused on urban areas because high population density and industrial activity contributes to waste in the environment. We examined six areas across Australia:

• Perth in Western Australia
• Port Augusta in South Australia
• Hobart in Tasmania
• Newcastle in New South Wales
• Sunshine Coast in Queensland
• Alice Springs in the Northern Territory.

These places represent a starting point for the national baseline. At each location we studied sites on the coast, along rivers and inland, within a 100 kilometre radius.

We inspected strips of land 2m wide. This involved two trained scientists standing in an upright position looking downward, slowly walking along a line surveying for debris items. Together they captured information about every piece of debris they came across, including the type of material and what it was originally used for (where possible).

What we found

On average, we found 0.15 items of debris per square metre of land surveyed. That’s roughly one piece of rubbish every five steps.

Plastic was the most common type of waste. But in many cases it was unclear what the item was originally used for. For example, fragments of hard plastic of unknown origin were found in a quarter of all surveyed areas.

Polystyrene fragments were the most common item overall (24% of all debris fragments). Other frequently encountered items included food wrappers or labels, cigarette butts, and hard plastic bottle caps or lids.

We found more waste near farms, industry and disadvantaged areas.

The types of waste varied among cities. For example, cigarette butts were the most prevalent items in Newcastle, Perth and the Sunshine Coast. But food wrappers and beverage cans were more prevalent in Port Augusta and Alice Springs, respectively.

Hobart had the highest occurrence of beverage bottles and bottle fragments.

Targeting problem items

Identifying the different types of litter in the environment can help policymakers and waste managers target specific items and improve waste recovery.

Research has shown container deposit legislation, which enables people to take eligible beverage containers to a collection point for a refund, has reduced the number of beverage containers in the coastal environment by 40%. Hobart did not have a container deposit scheme in place at the time of our survey.

Plastic bag bans can reduce bag litter. Now polystyrene food service items are becoming increasingly targeted by policymakers.

Making progress

When we compared our results to the previous survey from 2011-14 we found a 39% decrease in coastal debris. We also found 16% more areas where no debris was present.

Our results support previous research that found an ongoing trend towards less waste on Australian beaches.

We think our research demonstrates the effectiveness of improved waste management policies, campaigns such as the “Five R’s – Refuse, Reduce, Reuse, Repurpose, then Recycle” – as well as clean-up efforts.

It’s likely that increased awareness is making a big dent in the problem. But reducing the production of plastic, and invoking changes further up the supply chain, would likely further help reduce mismanaged waste in the environment.

Implications for the future

Measuring and monitoring litter can inform policymaking and waste management. Our research serves as a benchmark for evaluating and informing future efforts to reduce plastic waste.

We are heartened by the findings. But continued effort is needed from people across government, industry and Australian communities. Everyone needs to address how we produce, use and dispose of plastic for a cleaner and healthier planet.

As part of her role at CSIRO, Stephanie Brodie receives funding the federal Department of Climate Change, Energy, the Environment and Water, and the Australian Fisheries Management Authority.

Britta Denise Hardesty received funding for this work from the Department of Climate Change, Energy, Environment and Water. Shell Australia previously provided funding for this research via Earthwatch Australia for surveys and citizen science projects carried out between 2011 and 2014.