Urban Trees and Environmental Variables: Relationships in a City of Central Chile

Mauricio Ponce-Donoso, Oscar Vallejos-Barra, Benjamin Ingram, and Gustavo Daniluk-Mosquera

Abstract: We identified relationships between ecosystem services provided by trees and environmental variables, including temperature (°C at ground level and 1.5 m), relative humidity (%), particulate matter (PM10, maximum and average), noise (dBA), and ultraviolet radiation (UV at 1.5 m). This study was carried out in Talca, Chile, a mid-sized city. Measurement locations were selected in three areas based along three main avenues in the center of the city during three different seasons and three different schedules of day, generating 15,515 data in total. In circular plots, with 8 meter radiuses, measurements were recorded at the center and at a point on the perimeter. A correlation matrix was calculated and an ANOVA was conducted with canopy cover, schedule of day, and season as variation sources. The results show a high dispersion, and the correlation matrix that canopy coverage has a weak relationship with variables was studied. The results of the ANOVA showed the least number of significant differences associated with the canopy cover, schedule of day, and season, which showed significant differences for all variables. Tree coverage showed significant differences for all variables using the Tukey Test, with the exception of minimum noise. Plots with greater coverage were associated with increases in the particulate matter and relative humidity and decreases in maximum noise, temperature, and ultraviolet radiation. During mornings, the highest measurements of particulate matter, noise, and relative humidity were reported, whereas temperature maximums occurred at mid-day. The results confirm the importance of urban trees, specifically the canopy coverage, in mitigating negative environmental aspects in urban areas.

Keywords: Urban Trees and Environmental Variables: Relationships in a City of Central Chile

https://doi.org/10.48044/jauf.2020.007