Serviços ecossistêmicos de regulação climática e da qualidade do ar pela arborização em Patos-PB.

Abstract

The study of ecosystem services in urban forestry makes it possible to know more about the contribution of trees to mitigate urbanization effects and improve living conditions for the population. This study aimed to evaluate the capacity of tree species Tabebuia aurea and Azadirachta indica in providing ecosystem services for climate control and air quality in the city of Patos-PB, semiarid region of Brazil. To evaluate the bioindicator and bioremediation functions of these species regarding air quality, trees were chosen in ten public squares; five of them in area with high vehicle flow and five in an area with low vehicle flow, in the period between October and November 2015. In laboratory, the leaves were washed with distilled water to quantify the particulate accumulation, and leaf area was measured with imageJ® software. In the material from washing of the accumulation of particulate and in leaf samples, the content of Mg, S, Pb, Fe, Cu and Zn were determined. In fresh leaf material, chlorophyll a/b and carotenoid content were estimated to analyze the influence of particulate accumulation in photosynthetic pigments. In the evaluation of thermal comfort, there was the measurement of the ambient temperature and radiant temperature under and outside the tree canopy to estimate Thom's discomfort index. Then, normal t-test and paired t-test (p <0.05) for average comparison was applied. The T. aurea and A. indica species recorded, on average, particulate retention values of 37.65 µg cm-2 and 27.13µg cm-2, respectively. The photosynthetic pigments in T. Aurea constitute a good bioindicator of air pollution by particulate buildup. Chemical analysis showed that T. aurea and A. indica species meet bioremediation function of atmospheric pollution, especially T. Aurea. The lead content was higher in the solution from washed leaves than the one present in the leaf tissue. The ambient temperature and the radiant temperature measurements under the tree canopy of T. aurea and A. indica showed significant differences when compared with the recorded temperature outside the tree canopy. Thom's discomfort index was demonstrated as a not good indicator of thermal comfort for the city of Patos, semiarid region of Paraíba State.