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Marrickville streetscape.  There was more concrete behind me.

Marrickville streetscape – photo taken last week. There was more concrete behind me.

The news has been very tree-orientated in the last few days with Greg Hunt the Federal Environment Minister announcing that the government will have a vision for improved urban tree coverage within 18-months. See –

The federal government’s plan for cities is to increase the urban canopy every decade to 2050 to “reduce heat within city environments and improve health outcomes.”

“Green cities — cities with high levels of trees, foliage and green spaces — provide enormous benefits to their residents. Increasing urban canopy coverage decreases heat, which improves health and quality of life.”

Finally the urban canopy is being acknowledged as a health issue!  Recent research has found an increase in respiratory & cardiac illness with more fatal cardiac arrests in areas with a poor canopy. Add increased depression & obesity & you have an unhealthy, unhappy community, which ultimately has a cost on all of the community.

Unless there is a change of culture, I believe these problems will only increase with the current trend of high-rise housing with little or no green space or access to peaceful green space, as many of our parks are being transformed into entertainment areas.  Therefore, an Australia-wide initiative driven by the federal government to increase the urban forest canopy can only be applauded. We can have high-rise & green space. Green walls & green roofs can be incorporated into new designs just as easily as a pool for example.

The federal government’s announcement might be alarming for those state governments which are removing trees at a fierce rate in the push for development.  In Sydney alone 400 trees, many of them large Fig trees that are iconic to Sydney are being removed in Randwick for the eastern suburbs light rail project. This is despite Randwick Council saying that the light rail line can travel the same route without removing the trees. A whopping 760 trees will be removed along the entire light rail route.

The NSW government’s response to criticism about the tree loss has been that eight new trees will be planted for every tree removed. Sounds good, but I will watch with interest at what species of tree is planted, how many survive & what the canopy looks like in a decade. I highly doubt the canopy will ever look like it did in the beginning of December 2015.

Even closer to Marrickville LGA is Sydney Park at St Peters where 350 trees are being removed to establish a construction depot for the WestConnex Motorway.  See –  It seems that trees & green spaces are fair game for development, even when there are other options. Bushland at Wolli Creek is also threatened for WestConnex. The most expedient & cheapest way is to remove trees, yet the impact of doing so has far reaching consequences on both the community & the wildlife.

Then there is the 10/50 Code that allows for any tree to be removed within 10-metres of a home & remove underlying vegetation within 50-metres of a home without seeking approval because of bushfire risk. The North Shore & Pittwater areas of Sydney have been losing trees like they have no meaning.  The 10/50 Code offers a giant loophole for landowners to remove trees for any reason they like & according to Lane Cove Council, bushfire risk in the area is minimal. Still their urban forest has been decimated.

Globally 2015 was the hottest year since records started. 2011 to 2015 have been the hottest 5-year period world-wide since records started.  Sydney is expected to be like living in Rockhampton in subtropical Queensland by the turn of the century. See – Therefore, what is planted also needs to be taken into consideration if local councils want the trees to survive more than a few years.

Part of greening our cities, which also includes suburbs, requires a culture-shift of the community itself. Many areas of Sydney are defined by their trees – the North Shore, Pittwater, Eastwood area & Sutherland Shire as examples. Then there are suburbs with few trees, both public & private.

I took this photo in Bexley today.  This was one of a number of other street trees pruned like this.

I took this photo today in Bexley. This street tree has negligible amenity, except for the person who pruned it.  It adds no benefit to the wider community or to managing climate change

I think it may be a battle for a while until the prevailing attitude towards trees changes. To change public perception of trees, the government will need to embark on a strong multi-media education program. Twice in the past week I passed individuals in Marrickville who were casually pruning street trees into small stumps with no canopy.   That they do this in broad daylight shows that they believe that it is their right to do so & that they have little care or no conception that the street tree belongs to the whole community.

With luck, tree vandalism will become a rare occurrence, street trees will be planted in better conditions & the community will embrace the care of the tree by watering it while it is establishing & also during dry periods.

What will be wonderful in my opinion is that large canopy trees will become the norm because it is these trees that provide the most benefit & utility in cooling the streets & also in carbon sequestration.  It is also these types of trees that the federal government is talking about. I will be very pleased to see spindly street trees only used in spaces where there is no room for anything larger.

I will also enjoy the resultant beauty along our streetscapes when trees become more of a feature than buildings & where landscaping is used more often than concrete. Green walls & green roofs will be wonderful as well.

Lastly, greening our suburbs will bring wildlife in & support wildlife already here. Instead of the constant noise of traffic & planes, we will listen to white noise of bird song during the day & crickets & frogs at dusk. I know this to be true because the simple addition of some native trees & an under-storey has brought much wildlife to out place, whereas it was almost bereft when we moved in.

We have to change as individuals & as communities. Local Councils need to change as well. Much needs to be tossed out of current tree policies if they do not support increasing the canopy or the tree species chosen & placement does little to lower the urban heat island effect.  I suspect local councils will rapidly get on board with federal government directives, but I fear some in the community may find it hard to embrace an environment full of trees. We all have much to gain from a greener environment, from large canopy trees, to areas of under-storey filled with shrubs & plants & grasses & from being able to walk around without dashing from patch of shade to patch of shade.

Climate change will demand that everyone cooperates with the greening of our cities or we will suffer, cause our community to suffer & make it unlivable for future generations.


North Newtown streetscape providing lots of shade

North Newtown streetscape providing lots of shade.  This is a normal streetscape for this area.

Compare with a street in Dulwich Hill that actually has many street trees

Compare with a street in Dulwich Hill that actually has many street trees

There is an interesting article in The Conversation written by Prof. Rod Keenan & Benjamin Preston, both from the University of Melbourne.

Some points in the article –

  • Victoria currently has an average of 9 days per year of temperatures above 35C.  No action on greenhouse emissions will likely result in an average of 21 days a year with temperatures above 35C by 2070.
  • “Combine that with increasing urban density, more hard surfaces & less greenery, & a larger, older & more multicultural population, & the potential impacts from heatwaves start to multiply rapidly.”   Think of the development already in Marrickville municipality & the huge amount of development to come.

The Authors suggest two ways to help mitigate this & I think these are applicable Australia-wide –

  1. Increasing the ‘green infrastructure’ by 10%.  Green infrastructure means street trees, parks, green roofs, green walls & retaining water.

I’d suggest 10% is the absolute minimum, but can you imagine the positive change if the Marrickville urban forest was increased by 10%.

The City of Melbourne is planning on increasing their urban forest canopy cover from 22% to 40%. The City of Sydney is aiming to increase their urban forest by 50% by 2030 (just 16-years away) to help lower the urban heat island effect.

  • 2. Education.

“Health awareness programs can promote related benefits such as improved air quality; planners can reduce the red tape involved in planting street trees; local governments can identify priority neighbourhoods for development, protect existing greenery, & implement water-sensitive urban design.” 

“Increasing green infrastructure will also require the use of private space – one major challenge will be to give private landowners the incentive to keep or install greenery & incorporate vegetation into building design.”

Although Sydney has not experienced a true heatwave this summer, it has been very hot.  Melbourne & Adelaide both experienced two heatwaves this January, baking over a number days.  On 16th January, Adelaide was given the title of ‘the hottest city in the world’ with a temperature of 44.2C, still short of the forecasted 46C.

An article on Care2 discusses the American city of Phoenix trying to cope with 100-degree nights.  “The city averages more than 100 days a year with temperatures reaching over 100 degrees. (37.7C)   In 2013, 115 days hit 100 degrees. In 2011, the city set a new record for days over 110 degrees (42.3C) with 33. That’s over one month of the year with scorching highs. This winter has so far been warmer than average.”

Temperatures are rising everywhere.  The urban heat island effect is increasing those temperatures, & importantly, not allowing the temperature to drop after the sun goes down.  Phoenix has “a shade plan for the built environment & also a plan to “frankly just plant more trees.”  See –

We need to start planting now in both private & public spaces if we are to ever hope to be able to cope with projected temperatures.  Sydney’s temperature is expected to be like living in Rockhampton in Subtropical Queensland.  See –

Marrickville Council needs to decide how much to increase the urban forest & set & meet targets to achieve this.  The yearly budget allocation needs to be such to allow this to be achievable.   I have often wondered whether public trees & parks are lower down in the budget & whether these are seen as not as important as grey infrastructure.

Certainly we need to do what we can to keep the trees we have & this means treating them for diseases, fertilizing, mulching & pruning where necessary.

In my opinion, the community needs to help Council keep new trees alive by continuing to water trees once a week when Council has stopped water 12-weeks after planting.  It only takes a few hot days to lose a tree & if we look realistically, the bulk of our street trees are living in very harsh conditions.  Many are either hemmed in by concrete or in visibly dry & compacted soil.

I know there are many who will baulk at the idea of watering a public tree, but it is commonplace in many countries overseas.   The US for example, has a strong community involvement in public trees, whether planting them or looking after them.  Both the US & the UK have community ‘Tree Wardens’ looking after public trees.  These people are not tree experts.  They receive training by their Local Council to do the work they do.

Keeping that tree alive will help reduce your power bills as they help cool the air around your house.  Street trees clean up the air by removing particulate matter from vehicles, so better quality air comes into your home.  They also increase the value of your residence or business amongst many other benefits, so it stands to reason that taking care of the tree outside your property brings significant returns.  Better a living healthy tree, than a dead tree or a sapling that struggles to grow & may take many years to reach a decent size.

Older larger trees are far better at carbon sequestration than smaller trees – another reason why it makes sense to look after them.

You can read the full article here –

Tall shady street trees are the norm in Chippendale

Tall shady street trees are the norm in Chippendale

Canterbury Road - this section is mega-hot on a sunny day.

Canterbury Road – this section is mega-hot on a sunny day.

While there are street trees, this is still a hot street in Marrickville

While there are street trees, this is still a hot street in Marrickville

Shaw Street in Petersham is a good example of a good green street that has a lot of traffic. It’s not a wide street, yet tall reasonably closely spaced street trees have been planted.

We know that vehicle-related pollution & particulate matter is a public health issue as these can cause respiratory & heart illnesses/diseases & increased incidences of death.

In 2010, research from 700 worldwide health-pollution studies found that traffic pollution within a 500-metre radius of a major thoroughfare was likely to –

  • Exacerbate asthma in children
  • Trigger new asthma cases across all ages
  • Impair lung function in adults &
  • Could cause cardiovascular illness & death.  See –

We also know that street trees help improve air-quality by removing some of the vehicle-related pollution & particulate matter from the air.

Thanks to research published in June 2012 by researchers at the Lancaster Environment Centre at Lancaster University  we now know that that this level of pollution removal is actually much higher than previously thought, making humble street tree & other street vegetation more important than ever for human health.

Previous studies thought street trees captured less than 5% of air pollution from vehicles. The small percentage may have given an out for Councils not to have street tree planting as a priority.  However, this study from the Lancaster Environment Centre has shown that –

  • increasing deposition by the planting of vegetation in street canyons can reduce street-level concentrations in those canyons by as much as 40% for nitrogen dioxide & 60% for particulate matter.
  • Deposition rates of nitrogen dioxide & particulate matter to vegetation are much higher than those to hard, built surfaces.
  • Substantial street-level air quality improvements can be gained through action at the scale of a single street canyon or across city-sized areas of canyons.
  • Vegetation will continue to offer benefits in the reduction of pollution even if the traffic source is removed from city centers.”

I love what this property in Stanmore has done with the area along the laneway outside their house. You see this type of area often & mostly they are left to the weeds.

What wonderful research.  It clearly shows that the budgetary spending by Councils needs to be much higher for planting street trees & increasing the urban forest as trees are very much a public health issue.

Adding street trees & other vegetation should be a priority along main roads, secondary main roads & along shopping strips.  Verge gardens, pots filled with plants, green walls & hanging baskets are examples of vegetation that help to remove vehicle-related particulate matter.

As we know, street trees & other greenery also improves human happiness as well as increasing spending by around 11% along leafy shopping strips (by happy people).  Concentrating only on diet & lifestyle issues is not the only consideration public health should be looking at. Green streets full of street trees & other vegetation where trees cannot be planted is an important & vital step to ensuring a population can remain healthy.

Busy Glebe Point Road Glebe is a great example of a green shopping strip. It looks like this for most of its length. Where trees can’t be planted the City of Sydney Council has suspended large hanging baskets or reclaimed a parking space to plant a street tree. It look great & feels great too.  

Marrickville Road shopping strip with its few deciduous street trees always strikes me as bare

This section of very busy New Canterbury Road Petersham has looked like this for at least 3 decades.  




Young street trees & landscaping outside the old seagrass factory in Stanmore that has recently been developed into housing.

The Conversation – “an independent source of information, analysis & commentary from the university & research sector” has published yet another fabulous article, this time about trees.  The article was written by Gregory Moore – Doctor of Botany, University of Melbourne & published 30th January 2012.

Greg Moore Senior Research Associate of Burnley College, University of Melbourne was Principal of Burnley from 1988 to 2007, & Head of the School of Resource Management at the University from 2002 to 2007.  With a general interest in horticultural plant science, revegetation & ecology, Greg is particularly interested in arboriculture. He was inaugural president of the International Society of Arboriculture, Australian Chapter, & has been a member of the National Trust’s Register of Significant Trees since 1988 & chair since 1996. He has served the Board of Greening Australia (Victoria) since 1988 & chaired Treenet since 2005. He is on the board of Sustainable Gardening Australia & is a trustee of the Trust for Nature. He has written two books, contributed to three others & has published over 120 scientific papers & articles.”

‘The Conversation’ allows this article to be republished so here it is in full.  The use of bold is my emphasis.

For a great return on investment, try trees

Perhaps it is a pity that so many Australians think of our parks, gardens, streetscapes & urban landscapes only in terms of their aesthetics. While green spaces are beautiful & decorative, these attributes can mask the many functions vegetation serves in cities, to the point where its economic, social & environmental benefits are overlooked. Yes, trees are beautiful; but more than that, they save our cities a lot of money.

Cities are biodiversity hot spots because of the variety of habitats available in public & private open space, including front & back yards. Urban landscapes & trees have been wonderful but silent assets in our cities for decades & even centuries.

One of the many mature Fig trees in Johnson Park Dulwich Hill. They & other mature trees in this park are a real asset to this community.

They are major urban infrastructure assets. I often hear it said that; “There are better things to use water on than plants and gardens”, but I challenge you to name them. What else delivers so many benefits immediately: benefits that last centuries into the future, which prolong healthy lives & make cities both sustainable & livable?

At a time of climate change, it is worrying that both private and public open spaces are threatened by urban renewal & development that puts at risk long-term sustainability. In many of these developments there is insufficient open space – public or private – to plant large trees, & the opportunities for vegetation to ameliorate the heat island effect, lower wind speed, provide shade & reduce energy use are lost. This affects the economic viability of such developments, as well as its long term environmental sustainability.

The shade provided by trees drops temperatures by up to 8°C: there is real economic value in that. Shade can reduce air conditioner use by 12-15%, which also decreases carbon emissions from our largely brown-coal-generated electricity.

When 11 million trees were planted in the Los Angeles basin, it saved US$50 million per annum on air conditioning bills. Large trees were removed from school grounds in the name of safety after the Black Saturday fires, without thought of the shade they provided. Consequently, large shade sails had to be provided to protect students from excessive summer sun.

It is more difficult to place a value on reduced wind speeds (up to 10%) due to the presence of vegetation, or on protection that trees provide from hail. However, we do know that under climate change winds will be stronger & that severe storms will be more prevalent. Indeed, Victoria has already suffered the effects of several major wind & hail storm events over the past few years.

Urban vegetation also removes atmospheric pollutants. It was calculated that the vegetation of New York provided US$10 million of benefit in pollution removal in 1994. resources/downloads/Tree_Air_Qual.pdf  Sadly there are few similar studies for Australian cities. However in the only study of its kind, economists found that each Adelaide street tree provides a minimum annual benefit of $200 per year & that it was an under-estimate of the real value.

Vegetation also holds & absorbs water during more intense rainfall events – unlike concrete & paved surfaces. The economic value of reducing localised flooding could be substantial.

Vegetated landscapes, especially those containing trees, improve human heath, extend life spans, reduce violence & vandalism, and lower blood pressure.

Vegetation humidifies the air, easing breathing & reducing the need for medication in those with respiratory difficulties. In reducing the urban heat island effect, trees can also substantially reduce the excess deaths that occur, predominantly among the elderly, during heat waves. It is often forgotten that the fires of Black Saturday killed 172 people, but the heat wave surrounding it was responsible for 374 deaths.

Petersham is lucky to have such a lovely streetscape.

There is ample evidence that treed landscapes foster both active & passive recreation. Green & leafy environments will be one of the vital strategic tools in dealing with children lacking exercise & becoming obese, encouraging an ageing population to exercise & curbing ever-increasing health costs. The human health benefits can save society a truck-load on medical & social infrastructure costs.

Melbourne is one of Victoria’s biodiversity hot spots. The parks, gardens, streets & front and backyards provide a very diverse range of plant species that generate a myriad of habitats & niches for wildlife. High density urban developments & inner city renewal make it virtually impossible to grow trees in places that were once green & leafy. We rarely ever see the real costs of such developments.

In the past decade tree populations in many Australian cities have declined, particularly with the loss of private open space. While the costs, damage & nuisance values attributed to trees are widely known, the benefits they provide are often subtle & under-appreciated.

Urban vegetation provides economic & ecological services to society. They are assets which warrant the expenditure of resources such as labour, energy & water. Such expenditure is not wasted: trees & urban landscapes provide far more economically & ecologically than they use. In any comprehensive & fair calculation urban trees & landscapes are worth more than they cost.

* data-tracker

This article was originally published at  Read the original article –

Landscaping with young trees has been used to block off a road connecting with Ewart Street Dulwich Hill. It always looks good. Unfortunately one tree has been lost.


1.      In a shocking case of environmental vandalism, the Los Angeles County Department of Public Works chopped down around 250 100-year-old Oak & Sycamore trees across an 11-acre site called the Santa Anita Wash Oak Grove. The trees were razed so they can dump 500,000 cubic yards of silt that they intend to dredge from a nearby reservoir.  The community vehemently opposed the destruction of the Santa Anita Wash Oak Grove, but the destruction went ahead as planned & this in a state that prides itself on it’s climate change initiatives. I would have thought that the silt could have been transported to another place to be used rather than destroy a 100-year plus habitat.  To see the Santa Anita Wash Oak Grove for yourself, here is a 3.42min YouTube video –!   & article –,0,3043421.story

2.       We have always known it & now Australian research by Professor Burchett of the University of Technology Sydney has proven it …. pot plants relieve workplace stress. “We found that plants had a very strong wellbeing effect. It was a reduction of a whole lot of negative feelings: anxiety, anger, depression, confusion, fatigue & stress.” Trees are just bigger plants & have much the same benefits.

3.      In a bold move by the Natural History Museum of Los Angeles, 3.5 acres of carpark will be torn up to create an urban wilderness experience & exhibit.  What they intend to create by July 2011 is fabulous.  I hope this approach becomes commonplace.

4.      Glenn Ridge in New Jersey US has established a new Shade Tree Commission that will oversee the health & well-being of publicly-owned shade trees.  I have not heard of this type of body before. The Shade Tree Commission will ensue that the care of public trees is open & transparent & will work with the community via outreach & public forums.

5.      Polycyclic aromatic hydrocarbons  (PAH) are in coal tar which is used to seal roads & carparks. Heavy pollution of US streams, ponds & lakes has been tracked to the use of PAH.  Everything we use ends up in our riverways or oceans eventually.  It’s time we stopped opting for the quick solution & chose more natural non-polluting products. They are available.

6.      Research by scientists at the National Centre for Atmospheric Research found that deciduous trees absorb about 1/3 more of oxygenated volatile organic compounds & at a faster rate than expected, up to 4 times faster. Oxygenated volatile organic compounds are particularly bad for human health.  This is why as many trees as possible need to be planted along our main roads & thoroughfares.

7.      Scientists from the Swiss Federal Research Institute for Forest, Snow & Landscape in Zurich published research that examined “nearly 9,000 pieces of wood, mostly collected over the past 30 years by archaeologists who use tree rings to establish the age of ancient sites or structures, a technique known as dendrochronology. The result was a continuous – & precisely dated – record of weather in France & Germany going back 2,500 years. The study also showed that climate & catastrophe often line up.”

8.      Green building legislation & initiatives are becoming commonplace in the US with 12 federal agencies & 33 states implementing them despite the recession. In 2008, 156 Councils nationwide had green legislation. By September 2010, 384 Councils have jumped on board.  I like this as Australia often follows the US.

9.      ExxonMobil, the world’s largest oil company says they expect CO2 emissions to rise

Trees are essential in managing global warming

by nearly 25% in the next 20 years, “in effect dismissing hopes that runaway climate change can be arrested & massive loss of life prevented.  According to the UK Met Office, if emissions rises can be stopped by 2020 & then be made to reduce by 1-2% a year, the planet could be expected to warm 2.1C to 3.7 C this century, with the rise continuing even higher after 2100.” The Australian Bureau of Metrology said that ocean temperatures around Australia have already warmed by 1.5 degrees. A warmer ocean means greater evaporation, which leads to higher rainfall.  This lesson came via ABC TV on the day of the great flood that hit Brisbane & SE Queensland this past week.  I think this is a very important article.

10.      Every year the city of Paris has 95 collection points across the city where its citizens can take their unwanted live Christmas tree which are mulched to be used in the city’s parks & gardens. From 15,000 trees recycled in 2007-2008, the number grew to 27,150 in 2009-2010.” Does Marrickville Council have a collection for Christmas trees? If not, it would be easy enough to copy this initiative wouldn’t it?

11.       Sudden tree death is killing the older trees in the UK.Already 4 million trees have been felled or marked for destruction.” This is a tragedy.

12.       Friends of the Trees, a volunteer group in Portand have just finished planting their 400,000 tree since the group started 21-years ago. My deepest respect goes to them.

13.      In other good news, the Philippines have used Tree Surgeons to successfully heal sick

IKEA Fig January 2011 - doing well

trees. The emphasis is mine.  Researchers claimed 24 narra trees aged 68 to 73years old were treated after they were on the verge of dying considering that they were described to be landmarks when the construction of the Binga power plant & other facilities commenced in the early 1960s.  Seven trees had major treatments using steel bars as mechanical support during the tree surgery while the seventeen others underwent semi-major surgery.  Experts claimed tree surgery is the practice of repairing sick & damaged trees to subsequently restore its physical appearance. It is done by removing the injured or deceased parts & treating the same with antiseptics & healing aids & filling the cavities with special materials & cement to fix the surface.” Why does this not happen any more? Or if it does, why do we not hear about it?  I know some specialist Arborists look after veteran trees or move trees & care for them like the IKEA Fig, but this kind of work used to be done routinely on suburban trees. Now it seems like if a limb is sick, the whole tree has to come down.

Fantastic Fig tree in Marrickville Golf Course



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