Role of the urban vegetal in improving the thermal comfort of a public place of a contemporary Saharan city

The open public spaces, especially the public places, are for the population meeting, communication, conviviality. So that these spaces play their role they must be ruled by a comfortable physical environment. The optimal use of these spaces deserves detailed knowledge of all the elements that can improve the climatic conditions of use of these spaces. The purpose of this article is to study and analyze the role played by vegetation (urban vegetal) in urban external spaces since it is a fundamental component in this latter of which it minimizes and intercepts the solar rays, a very important factor of thermal comfort outside it reduces air temperatures generates shade; absorbs radiated fluxes and in general, it participates in the positive modification of physical environments (heat, humidity, light ...). Knowing that the people of the Saharan cities (hot climate and arid zone) seek to shelter solar rays by all means especially during the summer. To the latter, most of people are affected by thermal stress, given the lack of freshness and shade.This leads them to abandon the public place, and to join the built spaces, while using air conditioning, which engendered more energy consumption (electricity). The "in situ" investigation has affected the climate dimension ambient temperature, humidity, sunshine, solar radiation. And the insertion of urban vegetation (by simulation) as a mask against solar rays. The results confirm the primordial role of urban vegetal in the creation of shade, which has improved the thermal comfort of public places. Then the quality of urban life. Now it is limited, in this article, to expose a single example of the research. It is a public place (Ben Badis) in the city of Biskra / Algeria (dry climate and arid zone). The technique followed in this work is a combination of measures of the necessary climatic factors "in situ" and simulation using software.