Why did Council draft a tree strategy?

The strategy aims to provide direction around the management and protection of our much loved trees.

Where else is this type of tree management being undertaken?

Most councils across Australia have some form of strategic document or policy to guide the future direction of their trees.

Cities around the world now regard trees as critical urban infrastructure – just as important as roads or public transport. Furthermore, trees are seen as particularly vital to the health and wellbeing of communities. The benefits of urban forests span environmental, economic, cultural and political domains. These benefits are interrelated, with each cumulatively feeding into the creation of resilient sustainable urban landscapes.

What are the key issues proposed in the strategy?

The strategy provides a framework that will facilitate the regeneration of the Urban Forest in the City of Unley and provide sustainability for the City moving forward.

A range of initiatives, indicators and targets have been developed to ensure the long-term viability of our street trees, parks trees and private trees.

Through tree succession planning, the City of Unley will work towards a long-term goal to increase the species and age diversity of trees across the City, ensuring a healthier, environmentally sustainable, resilient tree population.

Why was diversifying the tree species flagged as an issue?

The Jacaranda and Queensland Box constitute over 42 per cent of Council’s street tree species. A reliance on a dominant species leaves the City vulnerable to pest and disease, and potential loss of the street tree asset.

Existing streets of Jacaranda will not be impacted. It is Council’s intention to maintain this species where it is the dominant species of a street.

Is there really any risk to our trees from pests?

A recent outbreak of the Elm Leaf Beetle is currently causing concern through Unley and Adelaide. The Elm Leaf Beetle is a relatively new pest occurrence within South Australia (first noted in Malvern, in 2011).

The beetle can cause major defoliation of the tree, and although the infestation will not initially cause tree death, prolonged attacks will inevitably reduce health and vigour and could result in expensive treatment.

There are currently no known threats to the Jacaranda and Queensland Box, but it would be irresponsible to not mitigate against potential future threats.

Does the plan propose to remove healthy Jacaranda trees?

The draft strategy does not propose to remove any healthy Jacaranda trees. Should a Jacaranda tree be removed due to poor condition or other necessary reason, it may be replaced with a different species.

In streets where Jacarandas are the dominant species, Jacarandas will continue to be planted as replacements are required.

Can changes still be made to limit diversifying the species?

All feedback received during the consultation period will be considered before drafting the final strategy for Council’s consideration and endorsement.

How do you decide which trees will be removed and replaced?

Trees have a finite life and strategically managing the asset is about knowing when intervention is required. There are many reasons why trees are removed, such as:

  • The tree is in severe decline
  • The tree is structurally compromised
  • The tree presents in poor health and condition with low vigour
  • The tree has a notable history of failure
  • The tree poses an unacceptable risk to people and property
  • The tree is on an unacceptable lean over road carriageway or footpath
  • Foliage density and distribution are drastically below normal levels
  • The tree species is no longer suitable for the Unley streetscape

How many street trees will be removed?

An independent audit of the City’s street tree asset has identified that around 1,600 street trees have a useful life expectancy of less than five years. This figure does not include yearly unexpected tree losses by unexplained deaths, storm damage etc.

With this in mind, we’ve set a five year target to replace 2,000 street trees. In the initial stages Council is targeting trees that are in poor condition or are structurally compromised.

Will all removed trees be replaced?

With a goal to maintain a healthy, environmentally sustainable, resilient tree population the Council intension is to replace all removed trees.

What types of trees will be used as replacements? Will they be natives, deciduous or evergreen?

Over the life of the Tree Strategy Council will aim to create a palette of trees suitable for replacement in the streets. This palette will include native, deciduous and evergreen.

Council is fully aware that many of the streets within the City of Unley have consistent avenues of same species trees. Existing avenues will be maintained and only changed after full consultation with residents and property owners within the street.

Will you let me know if trees in my street are being replaced?

Yes. Council is legislatively required to notify affected residents and property owners when nearby trees are removed.

Could Council meet its composition ratios by planting new trees between existing trees (rather than removing existing trees)?

Interplanting is rarely a viable solution as the new tree will often compete with the retained tree for moisture and sunlight. In the long term this can mean the new tree will be stunted or die. It is more sustainable if the tree is removed and replaced, allowing the new tree to establish.

Is there budget for this?

Council provides recurrent yearly funding for the maintenance of Council’s street tree asset. This funding includes provision for succession tree removal and replacement.

When will the strategy come into effect?

Following community consultation the feedback will be collated. Where deemed necessary the strategy will be amended. The strategy will ultimately be referred back to Council for endorsement.

It is anticipated that the strategy will be endorsed during the second half of the 2016 calendar year.