Published Date
1 September 2016, Vol.19:79–87, doi:10.1016/j.ufug.2016.07.005
Special Section: Power in urban social-ecological systems: Processes and practices of governance and marginalization

Author 

• Lyndal Plant ^,
• Neil Sipe 

• School of Geography, Planning and Environmental Management, University of Queensland, QLD 4072, Australia

Received 24 August 2015. Revised 6 July 2016. Accepted 8 July 2016. Available online 12 July 2016. 

Highlights

• •
  Pre-stratifying surveys using remotely sensed measures of street tree stem density and canopy cover reduces sampling error.
• •
  Downsizing street tree species may reduce capacity to achieve pathway tree shade targets in Brisbane.
• •
  Adaptive evidence gathering techniques support robust urban forest planning and policy review.

Abstract

Trees along footpath zones (or verges) grow on the “front-line” of urban forest ecosystems, increasingly recognised as essential to the quality of human life in cities. Growing so close to where residents live, work and travel, these street trees require careful planning and active management in order to balance their benefits against risks, liabilities, impacts and costs. Securing support and investment for urban trees is tough and robust business cases begin with accurate information about the resource. Few studies have accounted for spatial heterogeneity within a single land-use type in analyses of structure and composition of street tree populations. Remotely sensed footpath tree canopy cover data was used as a basis for stratification of random sampling across residential suburbs in the study area of Brisbane, Australia. Analysis of field survey data collected in 2010 from 80 representative sample sites in 52 suburbs revealed street tree population (432,445 ± 26,293) and stocking level (78%) estimates with low (6.08%) sampling error. Results also suggest that this population was transitioning to low risk, small-medium sized species with unproven longevity that could limit the capacity of the Brisbane’s Neighbourhood Shadeways planting program to expand from 35% footpath tree canopy cover in 2010, to a target of a 50% by 2031. This study advances the use of contemporary techniques for sampling extensive, unevenly distributed urban tree populations and the value of accurate resource knowledge to inform evidence-based planning and investment for urban forests.

Keywords

Pre-stratified sampling

Street trees

Urban forest structure and planning

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• ⁎ 
  Corresponding author at: School of Geography, Planning and Environmental Management, University of Queensland, Brisbane, St. Lucia, QLD 4072, Australia.

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http://www.sciencedirect.com/science/article/pii/S1618866715300121