Valuing ecosystem services of urban forests and open spaces: application of the SEEA framework in Australia

Around two-thirds of the global population will live in cities by 2050 requiring large urban infrastructure development. Decision-makers and planners usually rely on standard economic accounting methods for urban planning and investments on infrastructure assets. However, standard methods fail to account for the ecosystem services benefits that living infrastructure (e.g. urban forests, open spaces) provides to city dwellers. This could generate socially inefficient configurations of urban spaces and compromise the achievement of long-term urban sustainability targets. In this analysis, we applied a stochastic whole-of-life benefit-cost analysis following the System of Environmental-Economic Accounting (SEEA) framework to compare alternative long-term management strategies for living infrastructure in Canberra, Australia. Spatially explicit data, i-Tree Eco and benefit transfer methods were used to estimate the stocks and flows ecosystem services benefits of urban forests and irrigated open spaces from 2018 to 2070. Our analysis suggests that a '30 per cent canopy cover expansion' scenario has the highest benefit-cost ratio, while the business as usual scenario, where a net loss of 400 trees is expected per year, offers the lowest benefit-cost ratio. Scenarios of expanding versus not expanding irrigated open spaces in the future both result in a benefit-cost ratio of approximately two.