New research has revealed that most global cities, including Melbourne and Sydney, lack adequate tree canopy coverage, even though trees are abundant in urban landscapes. The study, published in Nature Communications, measured over 2.5 million buildings across eight cities using the ‘3-30-300’ rule, a benchmark for sustainable urban nature access.
Melbourne and Sydney Fall Short
The study found that only 3% of buildings in Melbourne’s inner suburbs had sufficient canopy cover, despite 44% of buildings having views of at least three trees. Central Sydney performed slightly better, with 17% of buildings shaded adequately, though 84% of buildings had views of three or more trees.
Lead researcher Dr. Thami Croeser from the Centre for Urban Research said urgent action is needed to increase tree canopy cover in cities to mitigate urban heat and promote mental and physical well-being.
“We know conditions like depression, anxiety, and heatstroke are more prevalent in areas without shady tree canopies and green spaces,” Dr. Croeser noted.
What is the ‘3-30-300’ Rule?
The ‘3-30-300’ rule, introduced by Dutch urban forestry expert Professor Cecil Konijnendijk, sets a benchmark for urban greenery:
- Every building should have a view of at least three trees.
- Neighbourhoods should have 30% tree canopy cover.
- Residents should be within 300 metres of a park.
While most cities met the “three trees” criteria, few reached the 30% canopy goal. Only Seattle (45%) and Singapore (75%) passed the benchmark.
Challenges in Urban Tree Management
The study highlighted that urban trees are often planted in poor conditions, such as asphalt-covered areas, which stunts growth and reduces canopy potential. Trees are also frequently removed for construction, utilities, or resident complaints, and replacement saplings rarely grow into full canopies.
“We often treat trees as an afterthought in urban planning,” Dr. Croeser explained.
Global Trends and Future Action
The ‘3-30-300’ metric is gaining international recognition, with cities in Europe, North America, and Asia integrating it into urban forestry strategies.
Dr. Croeser called for a state and federal government-led canopy taskforce to fund and fast-track urban tree initiatives.
“Local councils lack resources to achieve these goals on their own. A coordinated effort is essential,” he said.
With cities worldwide facing rising temperatures and urban health challenges, prioritizing tree canopy cover is seen as critical for creating more livable environments