A comprehensive guide to urban greening: more than adding trees
Melbourne’s been working hard at urban greening. And they’ve learned a lot about how it can be done, what mistakes get made, and how the public reacts.
We can probably all get behind more greenery and green spaces in our towns. But what does that look like and what considerations come up? Melbourne has a goal to achieve 40% canopy cover in the public realm by 2040. This breakdown by Ian Shears discusses what they’ve done, where they’re going, and what issues came up along the way.
Melbourne has been in a drought since 1997. It has many native, Western, and heritage trees throughout the city, and its parks are a staple of Melbourne life. The city has recognised the importance of diverse flora and fauna in public spaces (both to combat climate change effects and for the well-being of its citizens).
Ian Shears, team leader of Tree Planning in Melbourne, gives an overview of past and future urban greening in Melbourne from what trees to plant, to rain gardens, to green roofs and walls.
Something special about Melbourne are its heritage trees. Melbourne and its people want to protect these trees for a sense of history and pride, and because they’re beautiful. Some of these are important internationally. Certain century-old Elms live on in Melbourne despite many overseas having been decimated by Dutch Elm Disease.
But the ageing tree population means Melbourne expects 39% of its tree population to reach the end of their lives between 2014 and 2034. Additionally, much of Melbourne’s flora may not last because it can’t cope with the changing climate.
The previous strategy of replacing like with like resulted in over 60% of replanted trees failing. So, whatever’s planted next needs to be able to keep up with Melbourne’s ongoing drought, rising temperatures, and future projections for what the world will look like.
Still, residents are often hesitant to give up these ageing trees. After all, the nature around you can contribute to a sense of identity and sense of place.
So yes, we need to plant more trees. They’re good for the climate, our wellbeing, other creatures, and more. But we also need to make sure we are creating net growth, not just replacing what won’t last. And we need to approach replacement with care and compassion.
But trees aren’t the only solution. True urban greening and urban forestry mean more than just trees and parks. For instance, in the face of drought water-sensitive solutions are key.
Shears discusses the need for Water-Sensitive Urban Design. This is a philosophy that acknowledges how water is a key way that we connect with our environment. Its solutions tend to focus on drainage and stormwater, water-based ecosystems, and monitoring and protecting waterways.
Permeable pavements and rain gardens are common examples of WSUD. Rain gardens help drain excess water from the street. They have the added benefit of aiding tree growth and being carbon sinks in their own right. Trees grown with the help of rain gardens require 70% less water. Wetlands can be another part of WSUD, like Melbourne’s wetlands in Royal Park.
Urban wetland and rain gardens are already at work around Wellington, and a promising Green Network Plan… what can we do?
Then there’s the ever-exciting ‘green infrastructure.’ These include things like community gardens, urban agriculture, and green roofs and walls. Shears argues as cities get hotter and the urban heat island effect increases, thinking three-dimensionally about how we integrate vegetation into our cities will have great benefits. That means we’re going up.
Green roofs and walls are exactly what they sound like. Through a medium like soil or a growing mat, a layer of vegetation could become a part of a structure. Green infrastructure creates ‘micro-landscapes’ that act as carbon sinks and thermal insulators. They have great benefits such as further reducing stormwater runoff and cooling urban areas. Green roofs can also become gardens and community spaces, and they may even prolong the roof’s lifespan.
Plus, they’re gorgeous and help with people’s happiness, well-being, and senses of community and place.
There are some challenges with green roofs and walls. As they are relatively new, there are questions about best practice and what standards should be set for them. There’s also the question of money and regulation. These advancements may be more economically viable in the future, but that doesn’t help us now. That’s where incentives for implementation and innovation could be beneficial.
And then as we green up our spaces, we need to ensure we’re doing it everywhere. There has been a history in many places of wealthier neighbourhoods getting more trees, vegetation, and green infrastructure while poorer ones are neglected.
What can Wellington learn from all this? We can first think about what issues are specific to our context. Now that we know some of the mistakes we might run into, we can ensure we’re planting diverse and resilient flora, implementing effective blue infrastructure, and greening up our cities. And who knows, maybe there are some Aotearoa or Wellington specific innovations we’ve yet to dream up.
If you want to read Shears’ full breakdown and some extra research, click here.
- Wet Wet Wellington by Kate Spencer
- Wellington’s Water Sensitive Urban Design
- Melbourne’s Urban Forest Strategy from Melbourne City Council
- Cities are planting trees. Why not make them fruit trees? by Marigo Farr
- Melbourne’s Revegetation Project as a response to the pandemic by SmartCitiesWorld
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