The City of Melbourne’s urban forests are facing multiple challenges to their survival from climate change, population growth and urban heating. Over the next 20 years the city will experience a changing climate with higher average temperatures and more frequent and intense droughts and storm events.
Already the city’s urban forest is under stress from droughts and long periods of water restrictions triggering irreversible decline: Over the next 10 years 23% of Melbourne’s current tree population will be at the end of their useful lives and within 20 years this will reach 39%. To reverse this trend Melbourne has developed the Urban Forest Strategy: Making a Great City Greener to retain existing trees and plan the city’s urban forest of the future.
Melbourne’s urban forest of the future
The urban forest strategy’s vision is of a healthy, resilient and diverse urban forest that contributes to the health and wellbeing of the community, and to a livable city. To achieve the vision the strategy outlines a series of principles for decision-makers to follow that will transform an asset that has a current value of $700 million into a future value that is priceless. The principles include:
- Mitigating and adapting to climate change
- Reducing the urban heat island effect
- Designing for health and wellbeing
- Designing for livability and cultural integrity
- Creating healthier ecosystems
- Positioning Melbourne as a leader in urban forest
To achieve the vision the strategy has outlined specific targets including:
- Increase canopy cover: From 22% at present to 40% by 2040
- Increase urban forest diversity: No more than 5% of any one tree specie
- Improve vegetation health: 90% of the city’s tree population will be healthy
- Improve soil moisture and water quality: Soil moisture levels will be maintained at levels to provide healthy growth of vegetation
- Improve urban ecology: Protect and enhance biodiversity
- Inform and consult the community: The community will have a broader understanding of the importance of urban forests
Enhancing awareness on the value of urban forests
To ensure the community has a broader understanding on the importance of urban forests Melbourne is using the i-Tree Eco tool – a free peer-reviewed software suite from the U.S. Department of Agriculture’s Forest Service – that provides an urban and community forest analysis and benefit assessment tool. The tool provides an overview of the entire urban forest and is designed to use field data along with local hourly air pollution and meteorological data to quantify urban forest structure, environmental effects and value to communities. In New York the tool assessed that for every $1 spent on trees the return was $5.60.
The tool has been modified with the Victorian Local Sustainability Accord providing funding to the City of Melbourne, Port Philip and Moonee Valley to develop and contextualize the model for Australian conditions. Melbourne has trialed the i-Tree Eco tool with an assessment of 1,000 trees. The continued use of this tool in the future will be critical to evaluating, measuring and communicating the numerous benefits of urban forests to the city.
To ensure buy-in to urban forest preservation and enhancement actions cities need to convey to communities the numerous benefits – environmental, social and economic – trees provide.