To Tree or Not to Tree — that is the challenge

by Stephen McMahon, UDIA NSW Vice President Greenfield, General Manager of Macarthur Developments and Director of Inspire Planning. Stephen has been responsible for the planting over 5,000 trees in South West Sydney in the last five years.

People hate trees! There I have said it. You could accuse me of heresy by contradicting such commonly accepted orthodoxy. Why do I dare suggest such a perverse view?

One day over the Christmas break my neighbour lent over our shared fence and expressed concern about the bushfires. This is totally understandable. It was a grim time for all. I shared his concern.

He ventured on: Had I considered removing the sole tree in my postage stamp back garden in my inner west terrace? It was a significant bushfire hazard you know!

I advised him that, alas from his perspective, the tree would be staying. I felt confident that my lonely tree, being some 86 kilometres from the nearest bushfire was not a hazard to his home.

The coincidental thing is, I had only recently finished reviewing the draft Wilton DCP. Chapter 4.2.6 requires the planting of trees within a subdivision. One tree of at least five metres in height is required to be planted in the front setback of a dwelling while one tree of at least 8 metres in height is required to be planted in the rear garden setback area. Given these lots could have a width of circa 8 – 10 metres and the setback dimensions could be in the order of 4 metres achieving this control is going to be very challenging. Furthermore, I had in my hand recent advice from our Svengali-like NSW Rural Fire Service for a current subdivision I am seeking approval for. The advice (read “command”) prohibits the planting of any trees that result in a canopy within two metres of any dwelling. Confused?

So, I will qualify this opening statement. People hate trees … on or neighbouring their own property. They love trees … on someone else’s property, distant from perceived potential impacts. Yes, it is a genuine example of “not in my my backyard” (NIMBY) syndrome.

So how do we establish trees in an urban environment?

Image 1: A well treed high density inner city suburb of Sydney: Look carefully, most trees are located in the public domain.

Firstly, we don’t follow the proposed approach in the draft Wilton Development Control Plan.

There is no doubt that trees benefit urban environments. They improve streetscape appearance, provide shade, reduce heat island effects and offer psychological benefits. However, it is appropriate as this point to qualify this declaration with the debunking of some myths. Trees in urban areas have insufficient density to offer any noise attenuation benefits and analysis has shown that trees can actually exacerbate local air quality issues on major roads by obstructing air flow (ventilation) and thereby concentrating airborne pollutants.

The promotion of ‘greening’ goals and tree canopies cannot rely on strategies and town planning controls that are dependent upon the actions and support of homeowners and landowners (i.e. private property interests). Even if, by some miracle, a lucky tree survives the construction phase its days are probably numbered in the post-occupancy era as gardens become embellished with swimming pools, pergolas and the like. Government could enforce maintenance of trees on private property of course, but does Government want to be in the business of being the “tree police” on every housing lot in Western Sydney? [Image 1]

The public domain has to carry much of the burden of this goal. This however is neither altruistic nor unrealistic. Studies by the NSW Urban Design Advisory Service (remember them?) in the early 2000s, while investigating the efficiency of urban densities, found that when all public owned land is considered (that is basins, riparian corridors, parks, recreation, school sites and road reserves) it can make up to 40% of gross land area in an urban environment.

The promotion of tree canopy goals in the public domain has huge emotional value and support. However for Local Government (upon whom the burden for managing trees within the public domain would ultimately fall), it comes with a financial and operational cost.

Understandably Councils would object to this. However, the world is changing and our expectations on the role of the public domain are changing as we grow to appreciate the opportunities it offers and its value. Local Government can no longer operate following a “business as usual” philosophy. To get the discussion started here are a few suggestions:


    1. Abandon Agency Silos. Parks and environmental spaces could be multi-functional. For example, there is an opportunity (if open minds prevail) to combine open space, drainage and riparian functions. If this approach was co-ordinated cleverly with master planning and S.7.11 contributions its implementation creates new opportunities for dense tree planting that can extend into and establish a web of green across urban environments. On face value it may appear to cost more to manage. However the efficiencies it introduces by combining activities and reducing the land requirement burden on S.711 plans (remembering that land cost now makes up 30-50% of S.7.11 contributions) could be significant;
    2. Make better use of road reserves. Road reserves, and in particular road medians, offer a location to accommodate unencumbered street tree planting and stormwater infrastructure (e.g. rain gardens). This does not have to be wholesale across every street, but selected key streets such as Collector Roads and above;
    3. Abandon the use of automatic side loading rubbish trucks. The pick-up arm is the enemy of a street tree. This is not as unrealistic as it sounds. In fact, it is inevitable. As lot sizes get smaller and urban densities increase this method of rubbish collection will become increasingly inefficient and antiquated. Inner city councils like Sydney already know this;
    4. Adopt development controls that seek a greater density of planting during construction in the public domain, rather than on land destined to be privately owned. As developers we also recognise the value of trees. They uplift land values and increase marketability. However, we abhor flagrant waste;
    5. Councils need to learn to love trees. Trees are not characteristics of the public domain that cost money to maintain and create public liability issues. They are valued assets, important to quality of life and amenity. Councils in their various roles protect and manage the public interest. A lush green tree canopy located in the public domain is in the public interest; and
    6. Identify a suite of trees suitable for urban environments. Native trees are not good public or private domain trees. They are high maintenance, can be dangerous, often offer minimal tree canopy and can be unattractive (weakening public support and affection for their establishment and retention). Conversely exotics can be ‘too exotic’ and deciduous trees are high maintenance. There is an opportunity to run a horticultural competition to identify and promote a suite of tree species that are suitable for Sydney conditions and Council demands. An iconic signature tree for Western Sydney streets and public domain could be identified and promoted (similar to Brisbane City Council’s Jacaranda Street Tree Strategy, where ironically the tree is also a declared weed).

Obviously, the question arises of “who pays” for these outcomes in the public domain. It would be an interesting exercise to quantify the uplift in land values around such assets. This increased value could be captured in rates if the valuation system was more nuanced than it currently is today. Furthermore, residents are often more willing to pay higher rates in return for the increased amenity. Differential rating systems can facilitate this. At the end of the day, however, environmental improvements / conservation (for want of a better phrase) come at a cost. If we, as a community, support this, we must accept that Councils have a role and we must be prepared to assist in its realisation by paying for it in our rates.

The role for privately owned land

Notwithstanding the commentary above there is a role for privately owned land. Higher density residential and commercial development where efficiently managed by landlord, strata or community corporations provides perhaps the best opportunity.

Image 2: Extract of the Urban Redevelopment Authority (URA) Guidelines for Landscape Replacement Areas within New Developments.

In New South Wales we have only scratched the surface. There are celebrated examples overseas, most notably in Singapore. Singapore prides itself (and heavily promotes itself) on its garden city status. It heavily invests in its existing and new gardens, the new 100 ha Gardens by the Bay at Marina Bay being the most notable. It has also adopted planning controls and incentives to replace greenery lost on the ground from development with greenery in the upper levels of buildings through the creation of above ground terraces and gardens.

In the City’s ‘Downtown Core’ (including the Marina Bay Precinct) all development is required to comply with a 100 percent greenery replacement policy. The physical area of land used to accommodate the building footprint is required to be re-created within the building envelope to be used for green space. Elsewhere in the City, the National Parks Board has introduced the Skyrise Greenery Incentive Scheme (SGIS) where it will fund up to 50% of installation costs of rooftop and vertical (wall) greenery. Since its introduction in 2009, the SGIS has assisted in greening more than 110 existing buildings by retrofitting them with extensive green roofs, edible gardens, recreational rooftop gardens, and lush verdant green walls ( incentive-scheme). [Image 2]

The marked change to building presentation and the character of Singapore that has resulted is evident to even the casual observer as tourist photos can testify. [Image 3]

Inevitably the issue of construction quality and cost arises. This is particularly topical in Sydney at this time. Water penetration is a significant issue in development and clearly our procedures today have not quite been able to deliver the certainty and robustness that we require. More research is required including testing of new water proofing materials and construction methodologies. The additional structural requirements (and cost) is also challenging. However, as Singapore demonstrates, the added value justifies the investment.

At a local level there are also opportunities to increase tree planting on private property. However, by and large, these need to be achieved by incentives rather than enforcement. For example:

  1. The identification and adoption of an attractive, distinctive, functional and appropriate tree species (as discussed above) that can engender local resident pride and interest in their planting can assist enormously. This has emerged in Brisbane with Jacaranda trees very popular in private gardens. Closer to home, in New South Wales’ cooler climate towns like Orange, Bowral and Armidale the planting of deciduous trees that offer vibrant Autumn colours is also popular; and
  2. Can we use BASIX certification to incentivise tree planting? For example, tree planting can reduce energy demand by reducing the need for air conditioning.


In conclusion it is inevitable that our urban environments will have to accommodate more trees. Examples outside Sydney show that this can be achieved with a focus less on crude enforcement and more on inducement and innovation. Institutionally, and culturally, we are some way from accepting this necessity. It will require concerted attention, some research and a move away from ‘business as usual.’ Are we ready for this?

Image 3: One of Singapore’s more famous recent Downtown green buildings: Parkroyal on Pickering (WOHA Architects).