Research Centre: Virtual Reality Lab of Urban Environments & Human Health
Active Dates: May 2014 - May 2016
Title: Satellite imagery vs. eye-level photography: Evaluating associations among measurements of tree cover density at the site scale
Team: Bin Jiang, William C. Sullivan (Co-PI, U of Illinois)
Project Funder: USA Forest Service
Abstract: This study is an initial effort to understand the relationships among multiple measures of tree cover density and to identify their various advantages and constraints. At the site scale, top-down measures calculated using satellite image are not associated with eye-level measures of tree cover density when tree canopy cover is at a medium or high level. The findings presented here challenge the wide-spread use of top-down tree cover density as the dominant tool for guiding the design and management of urban forests. One promising way to overcome the challenges identified in this study would be to integrate measures of tree density from satellite imagery and eye-level photography and develop a comprehensive index of greenness that can more sensitively depict the urban tree canopy that people experience on site. Our findings warn urban forest professionals that heavy reliance on digital aerial photographs and maps may lead to landscape assessments and decisions that do not represent individuals’ eye-level experience of a site. Using eye-level photographs and visiting a site in person are still irreplaceable tools.