Forested Urban Canyons and Their Thermal Behavior in an Arid City

MARIA ANGÉLICA RUIZ; MARÍA BELÉN SOSA; CORREA ERICA; CANTON, MARIA ALICIA

JOURNAL OF ENVIRONMENTAL QUALITY

AMER SOC AGRONOMY

Año: 2015

0047-2425

The thermal behavior of cities is a by-product of urban morphology. The urban heat island (UHI) is a phenomenon that modifies the thermal behavior of cities, affecting residential energy consumption, air quality and outdoor comfort. Urban greening is an important strategy for the mitigation of UHI, among other benefits. This investigation focuses on the arid city of Mendoza, Argentina, which has been an oasis city since its origin. The city contains wide tree-lined streets, ?green tunnels?, but their extent has been reduced during the past two decades. Our research aims to define and quantify which variables ?material, urban canyon and forest structure? determine day and night air temperatures and to identify the best configuration. For this purpose, a field survey was conducted in a non-forested urban canyon (UC) and in 18 representative forested ones with Platanus x hispanica Mill., Morus alba L., and Fraxinus excelsior L. In addition, we took measurements to register microclimatic variables during the 2009-2010 summers. The data obtained were processed by Principal Component Analysis and Multiple Linear Regressions. As a result, three linear multivariate models, twenty nomograms and twenty-four forested and non-forested urban cross-sections have been graphed. As expected, non-forested urban configurations are the warmest (∆T=3.2ºC) and have the worst level of outdoor thermal comfort during the day. At night, low density UCs are up to 1.6ºC cooler than high density UCs. With these results, we encourage urban planners to include more forested streets in cities and to restore those that have been lost.