We speak for the trees:

Urban trees make tropical cities more liveable and substantially benefit urban dwellers. They temper urbanisation's harsher impacts, such as urban heat islands, improve air quality, foster biodiversity, and promote health and well-being, making them investments that yield significant returns.

However, maintaining healthy and resilient urban trees is challenging. Urban trees are often subject to stresses not typically found in more natural settings, such as increased exposure to wind due to the absence of a protective forest canopy and impervious surfaces limiting root growth and water access.

Additionally, managing urban trees can be challenging due to factors such as limited budgets, lack of public awareness about the importance of trees, and conflicting priorities between stakeholders.

Understanding the conditions of urban trees and their spatiotemporal dynamics can help facilitate management decisions towards more sustainable and resilient urban natural spaces.

The CSIRO-led  Darwin Living Lab  and  Urban Monitor  have generated high-resolution (20 cm) maps of Darwin's tree canopy cover for 2011, 2016, and 2021.  This information is useful for investigating spatial and temporal patterns of forest cover gains and losses in private and public land and the impacts of extreme weather events.   

Use the slider in the image below to compare tree cover and tree height change between 2011 and 2021.

Use the interactive map below to explore tree cover gains and losses between 2016 and 2021.

Between 2011 and 2021, the suburbs with the most significant change in canopy cover were Knuckey Lagoon, Berrimah, Leanyer, Holmes, and Coonawarra. These five suburbs lost over 50% of tree cover. In contrast, the suburbs with the least tree cover loss (<10% loss) in that period included Darwin City, Buffalo Creek, and Lyons.

Using statistical analysis, we identified areas of large tree cover loss (hot spots, red areas in the map below) and areas of low cover loss (cold spots, blue areas). The red circles indicate the areas with hot spots of tree loss, including areas close to Cullen Bay, East Point, Darwin Golf Course and Darwin's International Airport.

On average, private land has the largest share of Darwin's tree canopy cover at 42%, followed by Commonwealth Government land, NT Government land, and Local Government Council land.

From 2011 to 2016, tree cover gains were observed in most tenure types, with Commonwealth land presenting an 18% increase in tree cover.

From 2016 to 2021, there was a large tree cover loss in all land tenure types ranging from 26% to 40%.

Most tree canopy cover managed by City of Darwin is in road reserves (left chart panel). From 2011 to 2021, tree canopy cover in road reserves decreased by 78 ha, followed by parks (40 ha) and ovals (21 ha).

In terms of per cent asset area covered by trees, ovals have the largest cover, followed by Parks and Road Reserves (right chart panel). From 2016 to 2021, per cent tree canopy cover in ovals decreased by 22%, parks lost 15% and road reserves decreased by 9%.

The Darwin Living Lab and the City of Darwin have estimated the average replacement cost per hectare of tree cover to be $879,000 dollars (this only includes costs related to trees, not the cost of land). There was 152 hectares of canopy cover loss between 2016-2021.

There is also a loss of benefits from tree ecosystem service provision including carbon sequestration, avoided stormwater runoff, avoided carbon emissions, air pollution reduction, and building energy saving. This accounts for about almost one million dollars.

The loss of trees between 2016-2021, amounted to a loss of about $134 million for the replacement value of trees in the City of Darwin boundaries.

The City of Darwin, the Northern Territory Government, and Non-Government Organisations are working together to rebuild Darwin’s urban forest with strategies to increase its resilience to cyclones.

The Darwin Living Lab will continue tracking changes in tree canopy cover to help inform decisions for rebuilding and improving the resilience of Darwin’s urban forest. Further, the Darwin City Deal is advancing innovative heat mitigation methods beyond just tree planting, including the application of lighter, reflective surface treatments, incorporation of green spaces, and construction of shade structures. These strategies can effectively lower urban temperatures while trees mature, and also provide viable alternatives in areas where tree growth is not feasible. Emphasizing the importance of a multi-pronged approach, the Darwin City Deal is piloting several experimental heat mitigation projects, like the initiative on Cavenagh Street and the redevelopment of Civic and State Square, thereby bolstering resilience and adaptability in addressing urban heat challenges.

“The planting of trees is the planting of ideas. By starting with the simple act of planting a tree, we give hope to future generations" - Wangari Maathai, Nobel Peace Prize laureate