Trees can add $50,000 value to a Sydney house, so you might want to put down that chainsaw



Allowing residents to remove trees within three metres of buildings or ‘ancillary structures’ could dramatically alter the green infrastructure of dense inner Sydney suburbs like Rozelle.
Tom Casey/Shutterstock

Sara Wilkinson, University of Technology Sydney; Agnieszka Zalejska-Jonsson, KTH Royal Institute of Technology, and Sumita Ghosh, University of Technology Sydney

Sydney’s Inner West Council has a new policy that it is reported means “residents will no longer need to seek council approval to prune or remove trees within three metres of an existing home or structure”. Hold on, don’t reach for that chainsaw yet, because research shows good green infrastructure – trees, green roofs and walls – can add value to your home.

Green infrastructure offers significant, economic, social and environmental benefits. Urban greening is particularly important in dense urban areas like Sydney’s Inner West. Among its benefits, green infrastructure:

Some of these benefits accrue to owners/occupiers, whereas others provide wider societal benefits.




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Higher-density cities need greening to stay healthy and liveable


A 2017 study focusing on three Sydney suburbs found a 10% increase in street tree canopy could increase property values by A$50,000 on average. And the shading effect of trees can reduce energy bills by up to A$800 a year in Sydney. So retaining your green infrastructure – your trees, that is – can deliver direct financial gains.

On a larger scale, a collaborative project with Horticulture Innovation Australia Limited compared carbon and economic benefits from urban trees considering different landuses along sections of two roads in Sydney. Higher benefits were recorded for the Pacific Highway, with 106 trees per hectare and 58.6% residential land use, compared to Parramatta Road, with 70 trees per hectare and 15.8% residential.

For the Pacific Highway section, total carbon storage and the structural value of trees (the cost of replacing a tree with a similar tree) were estimated at A$1.64 million and A$640 million respectively. Trees were also valuable for carbon sequestration and removing air pollution.

Tree species, age, health and density, as well as land use, are key indicators for financial and wider ecosystem benefits. Specifically, urban trees in private yards in residential areas are vital in providing individual landowner and collective government/non-government benefits.

Take away the trees close to these houses in Marrickville, in Sydney’s Inner West, and how much would be left?
Graeme Bartlett/Wikipedia, CC BY-SA

Challenges of growth

As populations grow, cities increase density, with less green infrastructure. The loss of greenery affects the natural environment and both human and non-human well-being.




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We’re investing heavily in urban greening, so how are our cities doing?


Tree canopy cover across Greater Sydney plummets closer to the city centre.
© State of New South Wales through the Greater Sydney Commission. Data: SPOT5 Woody Extent and Foliage Projective Cover (FPH) 5-10m, 2011, NSW Office of Environment and Heritage

Trees and other green infrastructure reduce some impacts of urban density. However, policies, government incentives and national priorities can produce progress in urban greening or lead to setbacks. In the case of the Inner West Council, for instance, the inability to fund monitoring of changes in tree cover could lead to reductions at the very time when we need more canopy cover.

Key concerns include installation and maintenance costs of green infrastructure (trees, green roofs and walls) in property development, and tree root damage. Knowledge and skills are needed to maintain green infrastructure. As a result, developers often consider other options more feasible.

In the short and long term, multiple performance benefits and economic and environmental values are needed to establish the viability of green infrastructure.




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Australian cities are lagging behind in greening up their buildings


Learning from Stockholm

Stockholm shares many issues found in Australian cities. Stockholm houses over 20% of Sweden’s inhabitants, is increasing in density and redeveloping land to house a growing population. Aiming to be fossil-free by 2050, Stockholm acknowledges the built environment’s role in limiting climate change and its impacts.

In a research project we intend to use virtual reality (VR) and electroencephalogram (EEG) technology to assess perceptions of green infrastructure and reactions to it in various spaces.

Our project combines VR with EEG hardware, which measures human reactions to stimuli, to learn how people perceive and value green infrastructure in residential development.

Identifying all the value of green infrastructure

The many benefits of green infrastructure are both tangible and non-tangible. Economic benefits include:

  • those that directly benefit owners, occupants or investors – stormwater, increased property values and energy savings
  • other financial impacts – greenhouse gas savings, market-based savings and community benefits.



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If planners understand it’s cool to green cities, what’s stopping them?


The various approaches to evaluating net value present a challenge in quantifying the value of green infrastructure. The most common – cost-benefit analysis, triple bottom line, life cycle assessment and life cycle costing – are all inadequate for evaluating trade-offs between economic and environmental performance. Conventional cost-benefit analysis is insufficient for investment analysis, as it doesn’t include environmental costs and benefits.

This is salient for green infrastructure, as owners/investors incur substantial direct costs, whereas various shareholders share the value. Perhaps, in recognition of the shared value, a range of subsidies could be adopted to compensate investors. Discounted rates anyone?

Recent efforts to evaluate the business case for green infrastructure include attempts to identify and quantify the creation of economic, environment and community/social value. However, an approach that includes a more comprehensive set of value drivers is needed to do this. This is the gap we aim to fill.

The results of experiments using VR and EEG technology and semi-structured interviews will provide a comprehensive understanding of green infrastructure. This will be correlated with capital and rental values to determine various degrees of willingness to pay.

With this knowledge, property developers in Sweden and Australia will be able to make a more informed and holistic business case for increasing green infrastructure for more liveable, healthy cities.

Maybe we can then persuade more people, including those in the Inner West, to hang onto their trees and leave the chainsaws in the garage.The Conversation

Sara Wilkinson, Professor, School of the Built Environment, University of Technology Sydney; Agnieszka Zalejska-Jonsson, Researcher, Division of Building and Real Estate Economics, KTH Royal Institute of Technology, and Sumita Ghosh, Associate Professor in Planning, School of the Built Environment, University of Technology Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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NSW’s water plan is ‘not working’ but we can save the Barwon-Darling


Barry Hart, Monash University

The plan to manage water in the Barwon-Darling is not working, according to a draft review released last week.

The New South Wales Natural Resources Commission, which released the draft report, found the Barwon-Darling is an “ecosystem in crisis”. The report provides a robust blueprint for a more sustainable water-sharing plan.

The review confirms criticism the existing plan gives too much water to irrigators and has added to pressures on the entire Murray-Darling ecosystem.




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5 ways the government can clean up the Murray-Darling Basin Plan


What the plan covers

The draft review examines the 2012 Water Sharing Plan for the Barwon-Darling, which covers 1,600km of the river from Mungindi to Wilcannia. The river here flows south-west through a relatively narrow floodplain with a tightly meandering channel and a highly variable flow pattern.

The river is unregulated and depends heavily on upstream rivers for its water (for example, Condamine–Balonne, Border rivers, Gwydir and Namoi).

January’s massive fish kills around Menindee are only the most recent example of the pressures on the river’s ecosystems. Alongside the fish deaths, research has shown that other aquatic species in the system, such as river mussels, have suffered losses that will take many decades to recover.




Read more:
We wrote the report for the minister on fish deaths in the lower Darling – here’s why it could happen again


Communities that live along the river told the commission people can no longer fish, swim or drink the river water. Graziers struggle to provide water for their stock because the river dries up more often.

Indigenous communities are particularly affected because without water their strong connection to the river – the Barka – is being damaged. A Barkandji elder told the commission:

The river is everything. It’s my life, my culture. You take the water away from us, we’ve got nothing.

Bad priorities

While the review found drought, upstream water extraction in NSW and Queensland and climate change have all contributed to these problems, the greatest effect comes from inappropriate water-sharing rules, particularly when water levels are low.

The law underpinning river management in NSW prioritises protecting the environment and basic landholder rights (including native title) over irrigation. However, the commission found the current plan does not achieve this.

In fact, the plan has been highly controversial since it was enacted in 2012. This in large parts arose because major changes were made between the draft plan circulated in 2011 and the actual plan gazetted in 2012. The commission documents 16 such changes in the review and rates six as substantial.

The NSW government did not publicly explain the reason for such significant alteration in 2012, but there has been much speculation powerful vested interests influenced the government to provide more water for irrigation.

The most important effect of these changes was letting irrigators take water even when the river is very low. The review concludes:

These provisions benefit the economic interests of a few upstream users over the ecological and social needs of the many.




Read more:
The Darling River is simply not supposed to dry out, even in drought


What to do?

The review recommends the NSW government urgently change water-sharing rules so these better comply with the legal requirements to protect the environment and other water users, restore community trust and make the river more resilient to future shocks.

Key priorities for the NSW government are:

  • redesigning the water-sharing rules so environmental protection and basic landholder rights cannot be harmed by lesser priorities such as irrigation

  • introduce new flow targets to more effectively protect critical ecosystems and enhance river health

  • change rules relating to water extractions by A Class licence holders during critical low-flow periods, particularly those relating to commence-to-pump, cease-to-pump, and the size of pumps.

  • introduce and enforce more effective metering and monitoring

  • develop strategies and rules that address the inevitable impacts of climate change

  • develop and implement more integrated management of water resources in the northern Murray-Darling Basin.

The commission did note there have been positive changes to the NSW government’s approach to water policy and management since the ABC 4 Corners report Pumped in 2017 and the subsequent Ken Matthews report.

However, the Murray-Darling Basin Plan required NSW to complete a new water resource plan for the Barwon-Darling River by June 2019. The state missed this deadline. The NSW water minister has requested an extension to December 31 2019. A recent assessment by the Murray-Darling Basin Authority suggests NSW is still some way from completing this water resource plan.




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While NSW delays, the Barwon-Darling river system and its communities suffer. The NSW government now has an excellent blueprint for a new plan. It must urgently implement the review’s 29 recommendations and complete a new plan for the Barwon-Darling before the end of 2019.The Conversation

Barry Hart, Emeritus Professor Water Science, Monash University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Making deer fair game for unlicensed hunting is the right step for New South Wales


The fate of deer carcasses is a crucial consideration in monitoring the success of future culling.
Emma Spencer, Author provided

Thomas Newsome, University of Sydney and Emma Spencer, University of Sydney

The New South Wales government last week revealed plans to ease shooting restrictions on feral deer. If the plans go ahead, deer will be stripped of their status as a game animal and will no longer be afforded protection under the state’s animal control laws.

This will mean that a game hunting licence would not be required for recreational, commercial and professional hunting of deer species. Restrictions on how and when deer can be hunted would also be lifted.

Feral deer will be treated the same as other pest animals in NSW, including red foxes, feral cats and rabbits.

Deer are already considered a pest

Last year the NSW government approved 11 regional pest animal plans, each of which declared deer as a priority pest species. Several hunting regulations have already been suspended to manage abundant deer populations, and in February 2019 the government announced a A$9 million deer control program described as the most extensive of its kind.




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Removing the game status of deer is the next logical step towards controlling existing deer numbers in NSW, and slowing their spread to new areas. Deer currently cover 17% of NSW, and this area has more than doubled since 2009.

Deer now cover 17% of NSW.
NSW Dept of Primary Industries

Without urgent and effective control, the deer population could spread throughout the entire state and beyond.

Effective control is needed to stop the spread of feral deer in Australia.
Emma Spencer

The impacts of deer

Feral deer remain one of Australia’s least studied introduced mammals. Yet the evidence shows they have a substantial impact on Australia’s ecosystems and agriculture.

Since 2005, grazing and environmental damage by feral deer has been listed as a key threatening process under NSW legislation. Deer are known to graze on threatened plant species, and also cause erosion and soil compaction. They damage pasture; destroy fences and contaminate water sources; harm trees via antler rubbing; rip up the ground during rutting season; and potentially contribute to the spread of livestock diseases.

Deer are a threat to humans too. The Illawarra region south of Sydney, a hotspot for deer activity, has seen one death and multiple serious injuries between 2003 and 2017 due to vehicle collisions with deer.

Deer can also carry pathogens that cause human disease such as Leptospirosis and Cryptosporidium.

Choosing the right control method

Ground-based shooting is the main way to manage deer in the urban fringes, regional areas and national parks. Unfortunately, coordinated ground shoots have only been effective for areas of less than 1,000 hectares, and there is no evidence that uncoordinated shooting by recreational hunters actually works to control deer on a widespread basis.

Aerial shooting can potentially be more successful over large tracts of land, but may not be a good option when tree cover is high and visibility is low. Poison baiting could help, although there is no method available to deliver baits safely, effectively and specifically to deer.

Irrespective of the control method, a coordinated approach is needed. We need a strategy that not only controls deer where damage is worst, but also prevents their spread to new areas. This will require NSW to work closely with the ACT and Victoria.

A red fox feeds on a culled feral deer.
Emma Spencer

Rigorous monitoring will also be vital. This is important to gauge success (how many deer were culled, and the ethics of shooting, trapping and baiting), and to determine whether the control efforts have unintended impacts on the environment, such as deer carcasses providing food for scavenging pests.




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The protected pest: deer in Australia


Scavenging pests have been observed feeding on carcasses, but whether culling deer and other feral animals actually increases their abundance and impacts is unknown. Carcasses also provide a source of food for native scavengers such as eagles and ravens, and are integral to the structure and function of ecosystems.

The negative and positive impacts of deer culling on the broader ecosystem therefore needs consideration when developing and implementing monitoring plans. NSW can be the leader in this regard, starting from day one after removing the status of the deer as a game species.The Conversation

Thomas Newsome, Lecturer, University of Sydney and Emma Spencer, PhD candidate, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Billions spent on Murray-Darling water infrastructure: here’s the result


Q J Wang, University of Melbourne and Avril Horne, University of Melbourne

Earlier this year, researchers suggested the amount of water returned to the Murray Darling Basin under a federal program has been “grossly exaggerated”, to the tune of hundreds of billions of litres.

The report argued that government investment in irrigation improvements might even result in a net loss of water for the environment.




Read more:
The Darling River is simply not supposed to dry out, even in drought


To investigate these claims, the Murray Darling Basin Authority commissioned us to undertake an independent review to examine the best available data for every irrigation efficiency project funded across the basin.

We found the government investment into irrigation efficiency projects has achieved 85% of the 750 gigalitres per year target. The remaining 15% of the target may be affected by unintended side-effects.

This result highlights the need for continued review of risks to the basin plan, as Australia grapples with the management of an extraordinary complex natural system.

How is water for the environment recovered?

The Water Act 2007 introduced significant reforms aimed at setting aside more water for the environment. At the time, record high levels of surface water were being consumed. Aiming to save 2,750 gigalitres of surface water (water flowing in the open air, rather than underground) the federal government began buying back water rights and investing in more efficient infrastructure.

The Commonwealth is providing A$3.1 billion to buy these water rights, of which A$2.5 billion has been spent. It is also providing more than A$8 billion for modernising infrastructure and water efficiency improvements, of which more than A$4 billion has so far been spent.

These projects aim to improve water delivery – reducing leaks and evaporation – and make irrigation more efficient. The water saving generated from these projects is shared between the governments for environmental use, and irrigators.

Mass fish deaths earlier in the year raised serious concerns about the health of the Murray-Darling system.
DEAN LEWINS/AAP

What are “return flows”?

To understand why the government investment in irrigation efficiency projects have not achieved 100% of the original target, we need to talk about return flows.

When water is diverted from the river for irrigation, not all of it gets consumed by the plants. Some water will make its way back to the river. This is called return flow. A large part of the return flow is through groundwater to the rivers, and this part is extremely difficult to measure. More efficient infrastructure and irrigation generally means less return flow to the river.

If these reductions are not considered when calculating the water savings, it is possible there will be implications for irrigators, the environment and other water users downstream, that previously benefited from return flows.

What we tried to determine is how much the efficiency projects reduced return flow.




Read more:
We wrote the report for the minister on fish deaths in the lower Darling – here’s why it could happen again


Are the water savings real?

For the first time, we attempted to bring together data on individual projects in order to assess return flows across the basin. We developed a framework for calculating return flows, which took into account water in the rivers, groundwater, and efficiency projects.

This is the first attempt to bring together the existing data on individual projects to assess return flows in the basin at a detailed level. A large portion of the data used in this study was collated for the first time and not previously available in a readily accessible format.

We found a reduction in return flow of 121 gigalitres per year as a result of the government funded projects. This is comparable to 16% of the recovery transferred to environmental entitlements.

What does this mean for the Basin Plan?

There are several important details that must be considered to assess the importance of the return flow volume for the environment and Basin Plan objectives. We do not attempt here to quantify the outcomes, but instead to raise a number of important considerations beyond simply “volume”.

1. Recovered water should be legally protected

Return flows are good for the environment, but are essentially accidental. As irrigation becomes more efficient, inevitably they will diminish.

On the other hand, formally allocated environmental water entitlements are legally protected. It is more secure for the environment – and far easier to keep track of.

2. It’s not ‘efficiency vs the environment’

Part of this debate centres around the idea that reducing return flows means less water for the environment. But in Victoria and New South Wales, before water is allocated to anyone (irrigators or the environment), a base level is set aside. This is the minimum required to keep the rivers physically flowing and to meet critical human needs.

Efficiency projects mainly affect this base-level flow of the river. This means the water reduction is shared across everyone who holds a water licence – the majority of which are irrigators.

This policy means it does not make sense to compare the effect of efficiency projects directly with the recovery of environmental water.

3. Volume is a crude measure of environmental benefit

The focus of the debate around return flows has been based on the annual volume of returned environmental water in comparison to the stated Basin Plan target.

However, the real objective of the water recovery is to achieve environmental objectives in the Basin. This is not just about annual volumes, but the quantity, timing, and quality of fresh water.

How should we move forward?

Our review has particularly highlighted the need for better ongoing data collection and regular evaluations.




Read more:
Aboriginal voices are missing from the Murray-Darling Basin crisis


Both taxpayer investments and the water market are changing irrigation to become more efficient and reducing the river’s base flow. With this in mind, we need to regularly reexamine how we share water between everyone (and everything) that needs it, particularly in extended dry periods.

The Murray-Darling Basin is a constantly changing system, both in terms of climate and irrigation. Return flows are one of a number of potential threats to the Basin Plan. As the system is continually changing, these threats will need to be reassessed with each Basin Plan review.


A Four Corners program on the $13 billion Murray-Darling Basin Plan will air on ABC at 8.30pm on July 8.

This article was co-written by Glen Walker, a former CSIRO employee and now private consultant, who worked with the University of Melbourne on the independent review.The Conversation

Q J Wang, Professor, University of Melbourne and Avril Horne, Research fellow, Department of Infrastructure Engineering, University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Sydney declares a climate emergency – what does that mean in practice?


Chris Turney, UNSW

Late on Monday night, the City of Sydney became the first state capital in Australia to officially declare a climate emergency. With climate change considered a threat to human life, Sydney councillors unanimously supported a motion put forward by Lord Mayor Clover Moore to mobilise city resources to reduce carbon emissions and minimise the impact of future change.

The decision sees Sydney join a variety of local and national governments around the world, in a movement that is increasingly gaining momentum. In total, some 658 local governments around the world have made the same declaration, with the UK and Canada committing their national governments to the global movement in just the past two months.

An official declaration of climate emergency puts a government on a “wartime mobilisation” that places climate change at the centre of policy and planning decisions.




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UK becomes first country to declare a ‘climate emergency’


While interpretations differ on what a “climate emergency” means in practice, governments have established a range of measures to help meet the targets set by the Paris climate agreement. Under this agreement, 197 countries have pledged to limit global temperature rise to less than 2℃ above pre-industrial levels, and ideally no more than 1.5℃.

With 2018 having brought all manner of record-breaking climate extremes, and global average temperatures projected to reach 3.2℃ above the pre-industrial average based on current national pledges and targets for greenhouse emissions, Sydney’s recognition of a national emergency is both highly appropriate and also a major turning-point for Australia.

Although a signatory to the Paris Agreement, Australia’s greenhouse emissions have risen over the past four years since the repeal of the carbon price. With Australian emissions most notably increasing around transport, the United Nations climate discussions currently being held in Bonn have raised concerns over the nation’s ability to meet its Paris commitments.

Economic impacts

With the global cost of inaction on climate change projected to reach a staggering US$23 trillion a year by the end of the century (equivalent to around five 2008 global financial crises every year), several nations are already ramping up their Paris Agreement commitments ahead of schedule. The UK recently announced its intention to be carbon-neutral by 2050.

Australia is particularly vulnerable to the future financial costs of climate change, with economic models suggesting losses of A$159 billion a year through the impact of sea level rise and drought-driven collapses in agricultural productivity. The cost for each household has been put at about A$14,000.




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Cutting cities’ emissions does have economic benefits – and these ultimately outweigh the costs


After Sydney’s declaration, 150 faith leaders on Tuesday signed an open letter endorsing the decision, and describing the climate issue as a moral challenge that transcends religious belief. They have called for an urgent mobilisation to reach 100% renewable energy by the year 2030, and for an end to the approval of any new coal and gas projects, including Adani’s controversial Carmichael coal mine in Queensland.

The recent court ruling against the proposed Rocky Hill coal mine in the New South Wales Hunter Valley – a decision made partly on climate grounds – could mark a crucial turning point in the fortunes of future mining projects.




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As part of its emergency declaration, Sydney has also called on the federal government to establish a “just transition authority” to support Australians currently employed in fossil fuel industries. This is an urgent issue and a crucial part of the transition to a low-emissions economy.

A major nationwide training program will be needed to help re-skill the estimated 8,000 people who work in fossil-fuelled electricity production, and to help fill the tens of thousands of new jobs in renewable energy-related fields.

With the scale of change required to decarbonise the global economy and hopefully avoid a 2℃ warmer world, the need to support communities across Australia and overseas will likely become an increasing challenge for governments around the world. Putting ourselves on an emergency footing could help provide precisely the impetus we need.The Conversation

Chris Turney, Professor of Earth Science and Climate Change, ARC Centre of Excellence for Australian Biodiversity and Heritage, UNSW

This article is republished from The Conversation under a Creative Commons license. Read the original article.