Abstract

The relationship between leaf area index (LAI), ultraviolet radiation (UV) and temperature measured at 1.5 meters (T degrees 1.5) and at ground level (T degrees s) was studied, in three urban forest areas of Talca City, Chile. Circular plots with different tree projection coverage areas were defined for the registration of the T degrees and UV data. Measurements between 13 and 14 hours were performed and distributed for each year season, while the LAI was obtained with a single record per season; the selection zones and measurement points were done by a non-probabilistic method. The results showed that LAI, as a factor, had a statistical significance effect for UV, T degrees(1.5) and T degrees s, with 0.0081; 0.0058 and 0.0334 respectively (P <0.05), demonstrating that LAI is related as indicator of the mitigating function of urban forest, regardless of season of the year. The correlations were positive, although weak, as they failed to robustly explain their relationship with the measured variables; and LAI did not fully explain the variability that it has with T degrees s and T degrees(1.5) (r = 0.47 and r = 0.48 respectively), the same for UV (r = 0.38). In the context studied, it was not possible to determine that the LAI is an index that explains the variability presented, obtaining R-2 of 22.15%, 23.28% and 14.47% for T degrees s, T degrees(1,5) and UV, respectively, so the tree species and the characteristics associated with the plots, would explain the high dispersion of the results. The presence of trees favors the condition of T degrees and UV in the city pedestrian displacements.