Estimating the net benefit of street trees in Greater Adelaide Metropolitan, Australia
Urban greening, including planting street trees, is important to human health and wellbeing. Trees provide both ecological and economic benefits to society. However, recent data show that in many cities, including around the Greater Adelaide Metropolitan area, there is a decrease in the quantity as well as quality of greenspace. Urban developments have put pressure on existing greenspace in Greater Adelaide. There have also been concerns that the cost of maintaining urban greenspaces is too high, while street trees are sometimes seen as a nuisance because they can damage infrastructure like power lines, water pipes, and drainage systems.
This report presents an analysis of the total cost and benefit of planting street trees over a 60-year period in the Greater Adelaide Metropolitan. The costs include initial planning and establishment costs, annual maintenance costs, and externalities (or third-party costs) such as pruning to avoid contact with utility lines and maintaining damaged storm water pipes and drains. The benefits include the increase in property value, tree structural value, carbon storage and sequestration, reduced storm water runoff, pollution removal, energy savings, reduced emissions, and health benefits from reduced risk of heat-related illness. Several benefits are however not included in the analysis due to data limitations. These include species diversity, improved habitat quality as well as mental health and well-being benefits.
Initial results show that the benefits of planting street trees outweigh the costs in most councils in the Greater Adelaide Metropolitan. The average present value benefit of planting a tree, among the tree species examined in this study, is $11,236, while the cost is estimated to be $6,980. Preliminary results show that the benefits as well as costs vary depending on the tree species and the locations. It is important to note that this analysis is ongoing, and we have sought feedback from stakeholders to improve the accuracy of our analysis.
Understanding the benefits of street trees can help local decision-makers make informed choices about urban planning, and can also contribute to the global conversation about sustainable development. In recent years, the idea of urban greening has gained widespread attention as cities around the world grapple with the complex problems caused by rapid urbanisation and climate change. This report highlights the importance of street trees in creating healthier, more resilient, and more liveable cities.
