COS 96-3 - Is the future of cities green? Historical perspectives on urban greening reveal priorities for landscape management

Wednesday, August 9, 2017: 8:40 AM
E146, Oregon Convention Center
Dieter F. Hochuli, School of Life and Environmental Sciences, The University of Sydney, Sydney, Australia and Caragh Threlfall, School of Ecosystem and Forest Sciences, University of Melbourne, Richmond, Australia

The push to increase greenspace in cities is a global phenomenon, driven by the desire to enhance the liveability and sustainability of urban environments. While the positive impacts of increasing greenspace on human wellbeing and biodiversity are well known, the historical context for urban greenspace is rarely considered. We assessed the changes in green cover in over 70 years to identify how overall cover changed in 3 landscape uses; public parks, residential streets and natural areas/reserves. We used aerial imagery from 1943, 1961, 1982, 2003 and 2014 across multiple regions within Sydney, Australia to assess the changes in green cover over that time.


We found dramatically increasing green cover in all types of landscape across all areas. While cover in public parks and natural areas has generally more than doubled in the last 30 years, the most significant changes in cover occurred for street trees. In these areas tree cover often increased 5-10 fold, reflecting the extensive management of these areas. While this dramatic shift in the historical state of these landscapes from grey to green reflects a positive trajectory of change, cover alone may not be sufficient to reflect a successful outcome for the environment. To better plan for a range of environmental outcomes, there is an urgent need to identify how the quality, identity and extent of greenspace in different parts of urban ecosystems reflect their biodiversity value and contribution to human wellbeing .