A tree-planting decision support tool for urban heat mitigation.

Zoey R Werbin,Lucy R Hutyra,Tara K Miller,Paige Brochu,Tempest D Mccabe,Catherine Connolly,Sarabeth Buckley,Lucila Houttuijn Bloemendaal,Lindsey J Butler,Leila Heidari,Eda Ustaoglu

doi:10.1371/journal.pone.0224959

Abstract

Heat poses an urgent threat to public health in cities, as the urban heat island (UHI) effect can amplify exposures, contributing to high heat-related mortality and morbidity. Urban trees have the potential to mitigate heat by providing substantial cooling, as well as co-benefits such as reductions in energy consumption. The City of Boston has attempted to expand its urban canopy, yet maintenance costs and high tree mortality have hindered successful canopy expansion. Here, we present an interactive web application called Right Place, Right Tree—Boston that aims to support informed decision-making for planting new trees. To highlight priority regions for canopy expansion, we developed a Boston-specific Heat Vulnerability Index (HVI) and present this alongside maps of summer daytime land surface temperatures. We also provide information about tree pests and diseases, suitability of species for various conditions, land ownership, maintenance tips, and alternatives to tree planting. This web application is designed to support decision-making at multiple spatial scales, to assist city officials as well as residents who are interested in expanding or maintaining Boston’s urban forest.

Highlights

In a changing climate, urban areas are facing hotter, longer summers with more extreme heat events and increased heat-related mortality and morbidity [1, 2]
While some Heat Vulnerability Index (HVI) include a measure of temperature exposure within a single vulnerability index [21], the present approach allows the viewer of the decision support tool to visualize vulnerability (HVI) and heat exposure as two distinct factors which city governance may weigh differently
The Boston HVI was calculated based on methods used by Nayak et al [19] briefly summarized as follows: the 13 variables identified by Nayak et al [19] to be related to heat vulnerability were extracted from the American Communities Survey (ACS) 2009–2013 5-year estimate [23] and the 2011 National Land Cover Database (NLCD) [24]

Summary

Introduction

Urban areas are facing hotter, longer summers with more extreme heat events and increased heat-related mortality and morbidity [1, 2]. In Boston, for example, the heat-related mortality rate “may more than triple to 10.5 per 100,000 people under a moderate emissions reduction scenario or reach as high as 19.3 per 100,000 under the business-as-usual emissions scenario” by the 2080s [3]. Urban tree canopy can be an effective and relatively low-cost tool for reducing summer temperatures and air-conditioning costs [6,7,8,9], yet tree canopy is often unequally distributed along class and race lines [10,11,12]

Methods

Results

Conclusion