Effects of composition and structure variables of urban trees in the reduction of heat islands; case study, Temuco city, Chile

Abstract

The Urban Heat Island (UHI) effect is a growing problem that has a critical impact on human thermal comfort and public health. Some strategies to reduce the UHI effect are increasing the amount of urban forest. This research aims at assessing the effect of the composition and structure of urban trees, as part of cities's Green Infrastructure (GI), on the UHI phenomenon in the south of Chile. Linear regression analysis and non-parametrical statistical tests were used to assess the relationship. Micro-level features analysis demonstrates that shape and quality of trees have significant effect on temperature oscillations (p-value = 0.003 and 0.072, respectively). Better quality and larger area of canopy favour the refrigeration process. Besides, there are differences between native and introduced tree species behaviour, but they do not result significant. Composition and structure variables of the GI are relevant for dealing with the UHI phenomenon. Then, a proper management of the urban GI would ensure better and more sustainable planning of cities.