Spatial Distribution of Urban Vegetation: A Case Study of a Canadian University Campus Using LiDAR-Based Metrics

Abstract

Planners and urban managers design green spaces according to established standards, aspiring to create green spaces within and around the built environment. However, when building density is extremely high, it is difficult to design large, accessible green spaces. Urban green spaces are even more necessary when built density increases, and it is important to maintain urban vegetation—especially trees—as a major and integral part of the cities. Therefore, examining the distribution of urban vegetation is a tool for policymakers and community groups seeking to simultaneously moderate urban heat-island effects, and mitigate the effects of greenhouse gas emissions. The purpose of this study was to compare three different urban vegetation indices in a university campus for quantifying spatial relationships between green and gray infrastructure. Light Detection and Ranging (LiDAR) data were used to assess the distribution of urban vegetation. The indices varied significantly among various buildings according to their use categories (e.g., academic, administrative, etc.). These differences could be used to estimate the provision of ecosystem services for the various use categories and to evaluate trade-offs. For example, higher tree densities should provide greater rates of carbon sequestration and storage, as well as water retention and flood mitigation. Conversely, aesthetic and security considerations might favor lower vegetation density to preserve sight lines and vistas. The tools employed in this study have potential for use at greater scales, including entire cities.