One Million Trees Sydney is a project initiated by Greening Australia with the support of local and state government. This project involves the planting of 1 million trees across the Western Sydney region.
This project has been developed to combat the increase in temperature of Western Sydney. Since the 1960s, temperatures have increased by up to 6 degrees in this region1. Part of this increase is attributed to ‘urban heat island effect’ which is a worldwide condition affecting urban centres. Some of the factors of this condition are: size, materiality (thermal mass), building morphology (urban form, relationship between shape & height of buildings and open space), less water and vegetation, lack of humidity, heat created by human activities (transport industries and cooling systems) and atmospheric pollution2.
This project is in its early stages. Greening Australia has received government support and the project has opened its doors to donation. Every $10 sees a single tree planted and cared for in its early stages.
Western Sydney currently has a population of 1.96 million and is estimated to rise to 2.9 million by 2036. This project could be considered to provide 1 tree for every 2 people in the community.
This project works across scales: ‘the tree as a single unit – one million trees as a combined solution.’ Urban heat island is a global issue affecting many of our urban centres. This project works alongside similar replanting projects in other urban centres, combatting this global issue.
This project relies on support from government bodies, community groups and individuals for its success. Greening Australia will work with government bodies on the framework for tree planting, rally community groups for planting workshops, and encourage individuals to participate and take responsibility for the amenity of their urban environment.
The program is to plant one million trees. The strength of this project is in its simplicity. It teaches people about the importance of trees and vegetation in the city. At this stage, the location and method of dissemination is still being devised, but Greening Australia point to schools, community groups, families and environment restoration projects as their focus. Greening Australia will organise major planting days, planting trees in public spaces, on roadsides and in streetscapes. They will also organise workshops and giveaways to see trees planted in home gardens.
We can look to the precedent project of Greening LA for an example of how this process might take place.
‘Bushland and waterways are the lungs and veins of Sydney’ Philipa Walsh, CEO of Greening Australia3
Trees provide shade, and have an important role in the water cycle providing cooling to the air. Trees draw water from the soil and water table, and transpire it into the air as water vapour. This natural process has a cooling effect to the air surrounding the tree. Trees also replenish water to the soil and water table, breaking intense rainfall with their canopy, reducing runoff, and directing the water to their roots.
In urban centres and deforested areas, this localised cycle has been broken. Water falling on paved ground is directed through stormwater systems into our waterways and rivers. With reduced shade and increased thermal mass, our cities heat. The effects are an enlarged water cycle occurring at a large scale and ‘urban heat island effect’. Trees are pivotal in returning and sustaining a localised water cycle and cooling effect within our urban centres.
Challenges and Opportunities
Replanting trees has greater benefit than just reducing heat and water cycle. Other benefits include increase to air quality, biodiversity, site of play and amenity for communities. An interesting aspect of trees in urban centres is that the rate of stormwater catchment and transpiration is related to tree canopy size not permeable ground surface. This suggests that you can still use paving and hard surface in a sustainable way.
This project will also support education. Through this project, basic understanding of the importance of trees beyond amenity and beauty will be increased. There is also capacity for expanding education on planting practice, maintenance and upkeep towards personal investment and ongoing sustainability in our urban centres.