- The City of Salisbury has been propagating and planting an average of 50,000 trees per annum, with a peak planting season in 1997, totalling 212,000 plants in a year.
- The plantings were principally Eucalypts.
- Plantings in streets in most cases were tall varieties, ie., Sideroxylon and Euc. Intertexta.
- Many plantings in older suburbs were undertaken by developers, using poor planting techniques. There are no planning controls on subdivision landscape.
- Footpath damage was caused by trees in the majority of cases.
- Current expenditure on maintenance and footpath repairs is $560,000 per annum, 90% of which is due to failures caused by tree damage.
- Expenditure on this type of maintenance is $1.7 million per annum.
- There is an increasing public concern at damage to homes caused by clay shrinkage attributable to tree-related desiccation.
Community requests for action are interesting:
- 4,600 per annum for trees.
- 900 per annum for footpaths.
- 40 per annum for damage to houses.
- 400 per annum for kerb damage.
ACTION:
- To undertake an internal review of the current position by a cross-functional team comprising:
- Landscape Architect.
- Traffic Planner
- Engineer
- Horticulturalist
- To halt street tree planting pending completion of the review.
The following Recommendations were made by the team:
Recommendation 1:
That a review be conducted of Engineering and Horticultural techniques required to maintain streetscape vegetation.
Recommendation 2:
Undertake a review of existing policies, procedures & practices linked to any relevant legislation/guidelines affecting streetscape.
Recommendation 3:
Development & Implementation of a standardised Q.A. system that incorporates a policy & associated procedures for the selection, propagation and planting of streetscape species.
Recommendation 4:
Undertake a review of current Council procedures for establishing new sub-divisions in order to develop a clearly defined process that takes into account all streetscape elements at planning stage.
Recommendation 5:
Review existing methods for the provision, construction & maintenance of footpaths.
Recommendation 6:
That the City of Salisbury develop a set of guidelines that relate to the planting & maintenance of vegetation on traffic control devices.
Recommendation 7:
To develop a City of Salisbury Verge Policy which incorporates a clear set of procedures for all elements within the verge.
Recommendation 8:
Review existing guidelines for verge development by residents and the framework for their implementation, maintenance, and enforcement.
Recommendation 9:
To define all key City of Salisbury responsibility areas relating to the streetscape.
For example:
- What is our responsibility if plantings damage houses ?
- What is our responsibility to balance built form with soft form?
- What is our responsibility in managing developer landscapes ?
Recommendation 10:
The development and implementation of a planned and systematic training & education program. The success of all recommendations made by the streetscape team is dependent on this.
Strategies recently developed include:
- With the assistance of the Local Government Research Fund, the University of South Australia research arm has been engaged to undertake additional research to develop a policy for the establishment of streetscape at a location where the likelihood of tree damage to housing exists.
- The road reserve width included in AMCORD have been reviewed in accordance with on-site experience.
- Street tree types have been scaled back in ultimate height and base diameter. Planting of Sideroxylon have now ceased.
- In new subdivisions where we have been unable to achieve a street width to accommodate appropriate plantings, a distribution of trees to residents is proposed, accompanied by a set of guidelines on preferred location for planting, which is currently being developed.
CONCLUSIONS:
- A mass plant-out of trees, as carried out in Salisbury in previous years should be undertaken with an eye to the potential public concern relating to tree type, potential damage and maintenance costs.
- The debate on this issue is multifaceted, and will continue as long as hard and soft landscape elements are in conflict.
- The mass plant-out of trees as carried out in Salisbury in previous years should be undertaken with an eye to the potential public concern relating to tree type, potential damage and maintenance costs.
- To ignore the impact of trees on hard elements is not an appropriate strategy.
- The Development Plan should include provision relating to street-scape to afford councils control over the type and form of landscape.
What of the future ?
The following is an example of an integrated landscaping approach at Mawson Lakes:
- The principal driving force for integration was due to the sustainability principles in the Development Plan for Mawson Lakes.
- Commenced with a Master Plan for landscape, taking into account water consumption, water quality, landscape style and form, and the market target.
- The balance was achieved by:
- a water cycle plan which recycles 100% of water off the site – including stormwater and wastewater.
- Subsurface irrigation
- a balance of green and brown areas.
- a choice of plantings, achieving diversity of colour and form.
Thank you for the opportunity to contribute to the ongoing debate on “hard” versus “soft” landscape.
