Thermal and visual comfort under different trees cover in urban spaces at Constantine city centre - hot and dry climate

In urban environments, vegetated spaces have proven to act as ameliorating factors of some climatic features related to heat stress, reducing their effects and providing comfortable outdoor settings for people. The consideration of the thermal and visual outdoor conditions in cities is increasingly important for the well-being of man and the use of public spaces. Tree shaded areas can reduce the heat effect by amelioration of microclimate and human outdoor thermal comfort. The objective of this research is to investigate thermal and visual comfort and perception in tree shaded area in open urban spaces and to compare the performance of areas shaded by different types of tree coverage, including an open area without vegetation, located in a hot and dry climate. The methodology is based on a combination of an investigation conducted by structured interview, microclimate measurement. Measurements of air temperature, air humidity, wind speed, solar global radiation, luminance and the sky view factor combined with comfort surveys were performed during summer in different areas in the city center of Constantine in Algeria (a hot and dry climate). The results indicate that the percentage of tree coverage of a space is a highly important metric to assess outdoor comfort in a hot-dry climate and that it influences mainly the use of outdoor recreational areas. Dense vegetation cover optimises the microclimatic environment for pedestrians' thermal and visual comfort in urban spaces, under these climatic conditions.