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This study was carried out to determine the noise-reduction effectiveness of the Pinus sylvestris L. and Populus nigra L. trees along the E-80 State highway in Erzurum-Turkey. Noise values were taken at three measurement points; open (without trees and taken as control), the urban forests of pure P. sylvestris L. and P. nigra L. areas, and at four different distances; 0 (near the noise source), 25, 50 and 75 m from the noise source. At the distance of 25 m from the source, the noise value was 78.5 dB(A) in the control area, which was reduced 75.5 dB(A) and 69.2 dB(A) in the P. nigra L. and P. sylvestris L. areas, with the reduction rates of 24.7 and 31% compared to the control, respectively. This value was 69.6, 67.1 and 64.3 at the distance of 50 m and 64.9, 62.5 and 59.2 at 75 m for the naked, P. nigra L. and P. sylvestris L. areas, respectively. From the results of the study, it was suggested that for the noise pollution from the traffic flow on the roads, in especially the big cities, noise reduction zones with suitable width and plant species should be formed along the main arteries of the cities.

Trees in urban areas are important for their ecological functions in addition to their esthetic characteristics. Trees provide positive effects on urban microclimate by canopy, reflection, and transpiration activities; therefore, they help to decline formation of heat island. The objective of this study was to determine thermal effects of 15 different tree types: 4 coniferous and 11 deciduous species commonly found in the city of Erzurum located at the northeastern part of Turkey. The relationships between sky view factor and surface temperature regarding the differences in leaf density and tree species. In August 2016, the surface temperature of trees was measured using a thermal camera at 10:00 am and 4:00 pm hours. Sky view factor (SVF) was obtained by fisheye photos and physiologically characteristics of trees were determined. In all trees while the surface temperature was 20.1 °C at 10:00 am, it was 23.4 °C at 4:00 pm. Among the deciduous tree species, Betula verrucosa Ehrh. and Robinia pseudoacacia "Umbracuifera" had the lowest surface temperature; however, Abies concolor (Gord. & Glen.) had the lowest surface temperature among the coniferous tree species. The results indicated that the surface temperatures of different tree species varied considerably, and the SVF value had a significant effect on tree surface temperatures. However, it was obtained that the leaf types had no statistically significant effect on tree surface temperature.

RESUMENLa isla urbana de calor (ICU) y el confort térmico en espacios exteriores pueden ser afectados por diversos factores como el tamaño del entorno edificado, la proporción de espacios verdes y abiertos y los diferentes tipos de coberturas superficiales (e.g., pasto y coberturas artificiales) en zonas urbanas. De acuerdo con los tipos y estructuras de los pavimentos y materiales de cobertura, que pueden tener efectos en el albedo y el calentamiento superficial, las superficies reflejan la radiación solar o calientan el aire sobre ellas. Los pavimentos que absorben mayor cantidad de radiación solar la pueden convertir en calor, lo cual calienta el aire; esto a su vez eleva la temperatura de las áreas urbanas y provoca incomodidad en los seres humanos. El presente estudio investiga los efectos de diferentes materiales para cobertura de suelo en la intensidad de la ICU. Se consideran nueve tipos de materiales, a saber andesita, granito, basalto, travertino, madera impregnada, tierra, asfalto, polvo de ladrillo y pasto, los cuales fueron analizados en el jardín botánico de Ata en el centro de Erzurum, una ciudad ubicada en Anatolia oriental, Turquía. Las mediciones de temperatura superficial de estos pavimentos se llevaron a cabo durante julio en días soleados, a 150 cm sobre el suelo y a las 12:00 horas. Se utilizó para ello un termómetro infrarrojo (CEM-DT-8812) y, con el objeto de obtener temperaturas fisiológicamente equivalentes (TFE) para cada tipo de pavimento, los resultados se analizaron con el software RayMan 2.1. Posteriormente se analizaron estadísticamente las puntuaciones de TFE con una prueba de análisis de varianza y las diferencias en las temperaturas medias se evaluaron con la prueba de Fisher de la diferencia menos significativa. Los resultados muestran que los valores medios de TFE variaron de 28.9 ºC para madera impregnada a 25.9 ºC para pasto (una diferencia de 3 ºC). Las otras puntuaciones fueron las siguientes: 26.1, 26.7, 27.1, 27.5, 27.8, 28.5 y 28.5 ºC para travertino, granito, andesita, tierra, polvo de ladrillo, basalto y asfalto, respectivamente. Los resultados analíticos indican que todos los materiales estudiados crean un estrés térmico ligero (23.1-29 ºC) acorde con los índices TFE y los niveles de estrés. Sin embargo, el estrés térmico medido para la madera impregnada, el asfalto y el basalto fue mayor que para el resto de los materiales. Se determinó que el pasto, el travertino y los cubos de granito son las coberturas superficiales óptimas, ya que el nivel de estrés térmico que producen es el más cercano al rango de confort térmico (18.1-23.0 ºC). ABSTRACTThe urban heat island (UHI) phenomenon and outdoor human thermal comfort may be affected by several factors such as the size of the built environment, the rate of open and green spaces and different types of ground surface covers (e.g., grass and artificial covers) in urban areas. Depending on the types and structures of the pavement/covering materials, which can have effects on the albedo and surface heating, ground surfaces ...

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