A network of vigorous and extensive urban vegetation is critical to our health and wellbeing, and for protecting urban biodiversity. But how do we ensure we have abundant urban vegetation as our cities develop, consolidate and grow? Measuring and monitoring tree canopy and urban greening provides essential information to the government and community to support the management of our urban forests. This report presents an examination of the current and changing state of tree canopy cover in three Australian cities: Sydney, Melbourne and Perth. The project sits within a broader research context, “Making greening happen in consolidating cities”, funded through the Clean Air and Urban Landscapes (CAUL) research hub, National Environmental Science Program. The project is a collaboration between RMIT University, The University of Western Australia and CSIRO. This research has evolved in response to critical gaps in our understanding of the spatial variability in vegetation cover, structure, and change across our major metropolitan regions. The aim of this research was to understand the spatial distribution of urban vegetation, focusing on tree canopy cover, and its relationship with land-use; and to produce rich and targeted information to support decision making in practice. To address this aim, the following objectives guide the work presented here: o Provide tree canopy cover benchmarking data at the Local Government level for Greater Melbourne, Sydney and Perth, including the relationship with land-use. o Provide a detailed dashboard approach to analysing community level tree canopy cover performance including key metrics of canopy cover, canopy cover by land-use, and canopy cover change over time; and allowing for comparative assessment of performance. To deliver on these objectives we draw on high resolution, metropolitan-wide, mapping of vegetation cover for comparison with land-use activities and key policy implementations. We use high-resolution remotely sensed information of urban vegetation coverage (including canopy cover and total vegetation) mapped to a modified Mesh Block level, with land-use information derived from the Australian Bureau of Statistics (ABS). This enables detailed investigation of vegetation cover (particularly tree canopy) and the potential mitigating role of land management activity including land-use planning interventions. In this report, the spatial distribution of tree canopy cover in Sydney, Melbourne, and Perth is first reported followed by an assessment of canopy cover by major land-use classes across metropolitan sub-regions. This approach allows for an initial comparison and benchmarking of canopy coverage by Local Government Areas (LGAs) across each metropolitan region, as well as an in-depth examination of how tree canopy is distributed across various land-uses in each LGA. We then propose a Dashboard approach, consisting of maps, charts and indicators, that allows for in-depth assessment of community level urban forest performance and comparison against other communities. The Dashboard was designed to improve decision making fundamental to the enhancement and preservation of urban forest. Examples of the Dashboard results are presented for a selection of suburbs from Perth and Melbourne. Page 3 This report presents findings that pose challenging questions for urban policy and management with respect to canopy cover preservation and enhancement. But, also provides an evidence base to evaluate the very actions that support abundant and accessible vegetation across our ever-changing cities.
Additional authors: Saunders, A., Boruff, B., Duncan, J., Knight, G., Amati, M., Sun, C. Caccetta, P. and Chia, J.