Melbourne trees are under threat, with almost 44% projected to disappear in the next 20 years, so the city had to come up with a plan to includes increasing canopy cover and improving biodiversity, vegetation and soil moisture. The city was received an award of excellence for research, policy and communication from the Australian Institute of Landscape Architects, with judges calling their ‘Urban Forest Strategy – Making a Great City Greener 2012-20132′ a glowing example of ‘how to transform policy into practice to create a distinctive and liveable city’.
The City of Melbourne’s urban forest will be resilient, healthy and diverse and will contribute to the health and wellbeing of our community and to the creation of a liveable city. To link to full text click here
Melbourne is currently facing three significant challenges: climate change, population growth and urban heating placing pressure on the built fabric, services and people of the city. A healthy urban forest will play a critical role in maintaining the health and liveability of Melbourne. Over the next 20 years and beyond, Melbourne will experience a changing climate, becoming increasingly warm, dry, and liable to more frequent extremes of heat and inundation. The city’s urban heat island effect will intensify.
One of the important functions of the urban forest is to provide shade and cooling. Increased canopy coverage throughout the city will minimise the urban heat island effect and improve thermal comfort at street level for pedestrians. Increased water sensitive urban design will play an important role in managing inundation and providing soil moisture for healthy vegetation growth, as well as enhancing the city’s ecology.
Climate change science and international urban forestry research both indicate that a range of threats facing the urban forest will increase in the future, particularly vulnerability to pests, disease and extremes of weather. Melbourne’s residential, worker and visitor populations will increase. An associated growth in the urban forest, ‘green infrastructure’ and ‘ecosystem services’ would respond to these pressures, reduce the cost of grey infrastructure and improve the quality of the urban environment.
The recent period of drought and water restrictions triggered irreversible decline for many trees. This exaggerated the age-related decline of many significant elms and other trees. Modelling shows that within the next ten years, 23% of our current tree population will be at the end of their useful lives and within twenty years this figure will have reached 39%. To guide future planting, a series of tools and programs have been, and will continue to be, developed. Building the urban forest as a living ecosystem and ensuring that it provides the maximum benefits for our communities will rely on smart species selection, improving soil moisture retention, reducing stormwater flows, improving water quality and re-use, increasing shade and canopy cover, and reducing infrastructure conflicts.
Urban forestry is entering a new era in Australia and this strategy highlights how important it is, particularly in context of enhancing liveability and adapting to predicted climate change. An urban forest provides a multitude of benefits for ecosystems, the economy, and community health and wellbeing.
Photograph source: City of Melbourne
Principles, strategies & targets
The vision is of a healthy, resilient and diverse urban forest that contributes to the health and wellbeing of our communities, and to a liveable city that will create better urban environments for everyone. The principles outlined in the strategy are to guide decision-making to create a future forest. The strategy highlights proactive and adaptive management, and will transform an asset that has a current amenity value estimated at $700 million and a future value that is potentially priceless.
The strategy’s guiding principles are to:
- mitigate and adapt to climate change
- reduce the urban heat island effect
- become a ‘water sensitive’ city
- design for health and wellbeing
- design for liveability and cultural integrity
- create healthier ecosystems
- position Melbourne as a leader in urban forestry
The strategies and targets proposed to achieve this vision are:
- Strategy 1: Increase canopy cover Target: Increase public realm canopy cover from 22% at present to 40% by 2040.
- Strategy 2: Increase urban forest diversity Target: The urban forest will be composed of no more than 5% of any tree species, no more than 10% of any genus and no more than 20% of any one family.
- Strategy 3: Improve vegetation health Target: 90% of the City of Melbourne’s tree population will be healthy by 2040.
- Strategy 4: Improve soil moisture and water quality Target: Soil moisture levels will be maintained at levels to provide healthy growth of vegetation.
- Strategy 5: Improve urban ecology Target: Protect and enhance a level of biodiversity that contributes to a healthy ecosystem.
- Strategy 6: Inform and consult the community Target: The community will have a broader understanding of the importance of our urban forest, increase their connection to it and engage with its process of evolution.
The results of London’s i-Tree Survey are now available. The results of the London iTree urban forest survey were published on the 2nd December 2015 in the House of Lords. Attending was the host Lord Framlingham, Environment Minister Rory Stewart, Sir Harry Studholme (Forestry Commission Chair) and other senior representatives from London, the tree sector and the built environment sector.
The report has identified that the tree population of inner and outer London holds nearly 2.4 million tonnes of carbon and is sequestering an additional 77,000 tonnes per annum. This is equivalent to the total amount of carbon generated by 26 billion vehicle miles.
The report estimates the Capital Assessment Value (CAVAT ) – the functional, visual and social contribution value of London’s urban forest as £43.3 billion. London’s canopy cover is calculated at 21% and the most common species in inner London are Birch, Lime and Apple and in outer London it’s Sycamore, Oak and Hawthorn. It is also interesting to look at the sheer variety of species – 126 different tree species which is the highest recorded species diversity of any urban forest analysed with i-Tree in the UK.
“The importance of trees in the urban environment is unquestionable but is often minimised and lost amongst the myriad of other competing factors involved in urban space making, creation, management and maintenance.” Source: Sir Terry Farrell, CBE
“The millions of trees and shrubs in London’s parks, gardens, woodlands and open spaces are collectively described as London’s ‘urban forest’. This urban forest is part of London’s green infrastructure. It provides a range of ecosystem services that delivers multiple environmental benefits to Londoners. The scale and effectiveness of these benefits, such as air quality improvement, carbon sequestration or temperature reduction, are directly influenced by the way we manage the resource and decisions and actions that affect its structure and composition over time.” Source: London i-Tree Eco Project Report Executive Summary.
“This project demonstrates just how much can be achieved when we engage with the largest stakeholders of our urban forest – the public. Without them this study (the world’s largest urban forest survey using citizen science), this report, and what it reveals, would simply not have been possible. In addition, London has also developed a core group of trained and skilled i-Tree surveyors from all walks of life. They are now able to carry out further i-Tree Eco (and other tree) surveys, thereby helping to raise awareness of the benefits of London’s trees.” Source: London i-Tree Eco Project Report
The i-Tree Eco survey methodology was developed by the US Forest Service to assess the ecosystem service value of urban forests across the world. It has been used in Los Angeles, New York, Chicago, Barcelona, Melbourne and, closer to home, in Edinburgh and Glasgow. However, the London survey uniquely teamed professional volunteers with ordinary members of the public who all received training in the i-Tree Eco methodology. The survey element of the project could then be delivered solely by volunteers.
Lord Framlingham advocates the role of our urban trees in the UK’s House of Lords:
“Are we making the most of this incredible asset?”
The Landscape Interface Studio blog recently reported on the ‘Trees in the Townscape A Guide for Decision Makers Report’ – now Lord Framlingham has made a strong case for urban trees at the House of Lords on Thursday 15 January 2015 during a Natural Environment debate initiated by Lady Bakewell. Lord Framlingham called for a nationally coordinated approach to enhance the integration of trees in the design and management of hard landscapes. He commended the Tree and Design Action Group’s latest two publications and urged Lord de Mauley, Parliamentary Under-Secretary of State for the Department for Environment, Food and Rural Affairs (DEFRA) to “lend his weight to the distribution of these guides, or more particularly their contents, so as to co-ordinate and encourage the most enlightened and best practice everywhere”.
Less satisfactory was the lack of clear answer to Lord Framlingham’s question on who has responsibility for urban trees at a governmental level. It would appear that, despite the interest and good intentions towards urban trees demonstrated during the debate, the central question as to who is actually responsible for ensuring the urban forest and all the benefits it bestows is managed in the present and is sustained and developed into the future, remains unanswered.
Tree and Design Action Group – The group shares the collective vision that the location of trees, and all the benefits they bring, can be secured for future generations by influencing the planning, design, construction and management of our urban infrastructure and spaces.
“Trees make places work, look and feel better. As well as playing a role in climate proofing our neighbourhoods and supporting human health and environmental well-being, trees can also help to create conditions for economic success. This guide takes a 21st century approach to urban trees, providing decision makers with the principles and references they need to fully realise this potential.
This is an approach to trees that keeps pace with and responds to the challenges of our times. Trees in the Townscape offers a comprehensive set of 12 action-oriented principles which can be adapted to the unique context of your own town or city to provide a roadmap for trees in a 21st century context. Each principle is fully supported by explanations of delivery mechanisms, examples of the principle in practice and links to further references. Trees in the Townscape focuses on individual trees in the urban forest, whether highway trees, trees in public open spaces and housing land or private trees. It does not cover urban woodland management.”
Source: Trees in the Townscape A Guide for Decision Makers Report
Who should use the 12 principles?
The 12 principles in Trees in the Townscape are for everyone involved in making or influencing decisions that shape the spaces and places in which we live. It will be particularly relevant to local elected members, policy makers and community groups together with large land estate owners, such as registered social landlords. It will also be useful to those professionals who bring their technical expertise to facilitate delivery, such as engineers, architects, landscape architects or urban designers.
How were the 12 principles developed?
This guide was developed by the Trees and Design Action Group based on over 40 interviews and wide consultation with key knowledge holders in the built environment sector including civil engineers, insurers, developers, designers, planners, tree officers, sustainability specialists, arboriculturists, tree nursery managers, ecologists, academics, and not-for-profit organisations specialising in community engagement and trees.
- Know Your Tree Resource
Create and maintain easy-to-use records of the existing canopy cover and the nature and condition of the tree population.
- Have a Comprehensive Tree Strategy
Produce, adopt and implement a collaborative strategy for protecting, developing and managing a thriving, benefit-generating urban forest which is in tune with local needs and aspirations.
- Embed Trees into Policy and Other Plans
Adopt clear standards for the protection, care and planting of trees in the local plan and key corporate policy and investment documents.
- Make Tree-friendly Places
Create places where tree species can thrive and deliver their full range of benefits without causing harmful nuisance.
- Pick the Right Trees
Select and use trees appropriate to the context.
- Seek Multiple Benefits
Harvest the full range of benefits trees can deliver as part of a local green infrastructure system, focusing on key local aspirations.
- Procure a Healthy Tree
Plant healthy, vigorous trees that have been adequately conditioned to thrive in the environment in which they are destined to live.
- Provide Soil, Air and Water
Ensure trees have access to the nutrients, oxygen and water they need to fulfill their genetic potential for growth and longevity.
- Create Stakeholders
Work with local political, professional and community stakeholders to champion the value of trees in the townscape.
- Take an Asset Management Approach
Inform all planning, management and investment decisions with a robust understanding of both the costs and the value trees deliver.
- Be Risk Aware (Rather than Risk Averse)
Take a balanced and proportionate approach to tree safety management.
- Adjust Management to Needs
Conduct proactive and tailored tree maintenance to ensure optimum benefits in response to local needs.
To read the full report: http://www.tdag.org.uk/uploads/4/2/8/0/4280686/tdag_trees-in-the-townscape_november2012.pdf
London’s urban forest is increasingly recognised as having an economic value thanks to its environmental benefits. Trees give people a chance to be in direct contact with nature and attract woodland wildlife into even the most urban parts of the city.
The world’s largest survey of trees and woodlands is taking place in London. The survey will reveal for the first time the total tree cover in the capital and calculate the huge benefits they bring through boosting air quality, reducing flooding, and carbon storage.
The London iTree survey will see experienced foresters and arboriculturalists join hundreds of trained volunteers to measure trees in 725 plots across every borough. The survey teams will take detailed records of each tree in their plot, including stem diameter, tree height, size of tree canopy and condition of the tree. Other factors affecting the level of benefits that a tree can deliver will be recorded, such as land use and the amount of shrub and ground cover.
Matthew Pencharz, the Mayor of London’s Senior Advisor on Environment & Energy, said: “Whilst the beauty and intrinsic value of all the trees and woodland in London are recognised, most people are not aware of, or take for granted, the environmental benefits that they provide. This survey will highlight the immense value our trees bring to the our capital, and is part of our wider work to make London a greener city”
The survey will enable better planning of improvements to the number of trees in London and create a stronger understanding of their economic and environmental value. It will also help to deliver the Mayor’s target of increasing London’s canopy cover from 20 per cent to 25 per cent by 2025.
iTree software was originally developed by the US Forest Service to provide tools for analysing and assessing the benefits of urban trees. Free to use, it has since been used by local and national governments, other organisations and local communities around the world to strengthen their urban forest management and advocacy by quantifying the environmental services that trees provide.
The iTree methodology has been used on a smaller scale to demonstrate the value of trees in other parts of the UK, including a study in Torbay that found that the 818,000 trees there had a structural (or replacement) value of around £280 million, stored around 98,000 tonnes of carbon per year, and removed around 50 tonnes of particulate air pollution each year. The value and ecosystem services provided by London’s trees are expected to be far higher.
Hundreds of volunteers are helping carry out the surveys, including members of the Mayor’s Team London volunteering initiative. This is one of many green projects Team London are involved with including the Wide Horizons which is helping to transform a five-acre area in South London into a well-managed woodland.
The iTree survey is being co-ordinated by the Forestry Commission with support from the Mayor of London and the London Tree Officers’ Association. The survey concludes at the end of October and the results will be published in Spring 2015.