City trees bring many environmental and economic advantages. Their presence reduces carbon sequestration and air pollution levels, improve water flow, and even raise property values.
However, they are also vulnerable to various threats including drought and competition from other forms of vegetation. Furthermore, vehicles regularly damage them, while lawnmowers and string trimmers wreak havoc by overburdening them with too many cutting passes.
The Heatwave Challenge
Melbourne responded to drought, heatwaves and an ageing tree population by investing in an expanding urban forest through Living Melbourne - promising and delivering thousands of trees with its expanding canopy that offered both environmental and social benefits to its citizens.
Trees provide many environmental and economic benefits, from lowering urban heat and air pollution levels, increasing visual amenity and biodiversity, mitigating urban heat island effects, to increasing water flow during extreme events. Trees also help extend infrastructure’s lifespan such as roads, railway lines, water tanks and stormwater drains by protecting them from UV rays that would otherwise shorten its life expectancy.
City of Melbourne’s forestry workforce works tirelessly to ensure its tree population remains resilient against climate change, conducting regular health assessments, removing dead and dying trees and replacing them with healthy stock.
City of Melbourne is taking steps to increase structural diversity through planting in different street and park typologies, using species like Ulmus glabra (shady elm), Eucalyptus macrocarpa (sandstone ash), and Agathis robusta (Queensland Kauri). This diversity will enable its urban forest to better adapt to future climate conditions while offering resilience against heatwaves or other climate events; further supported by ground covers, shrubs or grasses in suitable locations.
Melbourne’s Urban Forest Strategy
As an early example of transformative policy and active citizen engagement, the City of Melbourne unveiled its urban forest strategy in 2013. Unlike other municipal strategies that only address street trees and canopy on public land, Melbourne’s strategy encompasses all treed areas within its borders, features performance measures and employs a broad definition of urban forest. Furthermore, Melbourne made a commitment to increase understorey vegetation such as small trees, shrubs and vines by six per cent in its parks - providing important habitat for small birds.
The Living Melbourne metropolitan-scale urban forest strategy was devised in collaboration between 32 local government authorities (LGAs), Victorian state government departments and agencies, the City of Melbourne and 100RC - making it a world first! LGAs mapped all treed areas within Melbourne Metropolitan area based on Plan Melbourne 2050 expansion as part of this strategy.
Living Melbourne was one of the first strategies to include detailed canopy cover data due to time and resource limitations, making a notable achievement of a new and highly complex methodology. Although not mandated to greening activities on geospatial urban land areas directly, its recommendations include strengthening regulations regarding greening activities in all new subdivisions/developments/private lands; expanding greening efforts on private lands; offering incentives for planting/protecting/maintaining urban trees/other natural infrastructure as well as incentives.
The Benefits of Green Infrastructure
As Melbourne strives towards its goal of net-zero carbon emissions, its extensive network of public open spaces has become one of its key resilience assets. Not only are these spaces visually pleasing features of Melbourne’s landscape; they also serve to reduce resource consumption and greenhouse gas emissions per person while mitigating urban heat islands and water scarcity, supporting sustainable lifestyles through active recreation, social connection and congestion reduction as well as air pollution reduction.
Attaining a more resilient urban environment will require taking an holistic approach that encompasses every element of a city’s ecosystem and includes activities like smart species selection, improving soil moisture retention, increasing canopy cover, reducing infrastructure conflicts and tree mortality rates, as well as improving water quality and reusing it effectively - and mitigating climate change risks. TNC’s Grey to Green program can help cities accomplish this objective while simultaneously realising social, environmental and economic benefits from street and park space preservation and reclamation efforts.
This program converts urban street and park space into high-quality recreation areas, meeting places, public art venues and more - at an extremely cost-effective and environmentally-friendly cost. Vegetation and trees offer recreational opportunities for people of all ages and abilities while simultaneously decreasing noise pollution from traffic, trains and planes; property values may increase significantly while improving biodiversity locally.
Successful Green Spaces
Urban green spaces provide numerous advantages, yet realizing them requires commitment, collaboration and innovation from all parties involved. Cities worldwide are taking steps towards greening by adopting “greenprinting”, an approach which brings together stakeholders in order to preserve, expand and connect natural areas on a metropolitan scale.
Melbourne is leading the way in developing Greenprint strategies as an invaluable way of building resilient and liveable cities. They show how biodiversity can serve as natural infrastructure against climate change while supporting biodiversity-rich ecosystem services that benefit humanity.
In Melbourne’s local area, the “Grey to Green” program transforms Council-owned sites like surplus road space and car parks into diverse public open space through high-quality design that integrates new spaces seamlessly into existing streetscapes, giving an impression that they have always existed.
Land use trends are also contributing to the decline of New York City’s urban forest. An increased preference for low density living in outer and new development suburbs, coupled with trends toward more grassy gardens and smaller lawn sizes has resulted in less trees being planted, which has only been compounded by our City’s ongoing drought, which has increased tree health risk significantly while necessitating more replacement plantings.
Climate change presents another daunting challenge to urban trees, which require regular surface watering and less extreme temperatures for survival, but its impacts will require more sophisticated species selection practices as well as adaptive water management practices to adapt.
Roadblocks in the Path of Urban Greening
Melburnians take great pleasure in creating the lush, shaded urban environment they have come to know and love in Melbourne, which requires ongoing commitment and effort. At present, the city spends about one million dollars annually on tree planting. As part of its strategy to increase canopy coverage to reduce thermal comfort reliance while expanding biodiversity via adding native vegetation species.
Melbourne’s urban forests depend on both population health and tree management to thrive, including knowledge of which trees are at risk of dying so replacement programs can be managed with minimum impact to communities. Furthermore, urban foresters must take into account how different tree species provide cultural services such as aesthetics, mental health support, social development or increasing property values.
City of Melbourne has historically used an online map to provide its 80,000 trees with information to the public. This map depicts their location, species and age as well as condition; helping identify when new planting or treatment of diseases might be needed.
The City of Melbourne will continue to develop its tree map and promote use of online tools, but must also strive to enhance engagement with its community. Melbourne’s green infrastructure resides mainly on private property; therefore it must work with developers to promote sustainable urban climate practices in new residential developments.
Future Ambitions for Melbourne’s Urban Forest
An effective path towards sustainable urban climate requires the collaborative commitment of an entire community that spans beyond electoral cycles. Expertise from planning, ecology, urban design and landscape architecture may need to be involved as well as partnerships formed between private land owners for urban greening projects as well as broadening knowledge base of tree species that offer numerous environmental benefits.
The City’s Integrated Urban Forest Strategy was created with community engagement at every step, creating an incredibly successful and inclusive process. It includes vegetation from all municipal streets and parks to open spaces such as urban open spaces and landscapes such as campuses, river and creek embankments, railway corridors and wetlands - as well as over 70,000 public domain trees as well as many thousands of private gardens, balconies and roofs in its scope.
This strategy establishes tree canopy and permeability targets on both public and private land, and recommends an objective method of long-term monitoring, evaluation, and reporting on the quality and extent of Melbourne’s urban forest. This work complements DELWP’s Plan Melbourne 2050 Action 91 which seeks to create a cooler and greener Melbourne. Both initiatives have received endorsement from organizations representing business, community, natural resource management sector, which demonstrates that their members support Living Melbourne and play an essential part in its implementation.