The aesthetic and environmental values of a street are greatly influenced by the selection of an appropriate arboreal species and the relation between its planted trees with the different engineering elements of a street . Street trees play a significant role in forming the architectural and aesthetic texture of the city. They, forther more, enhance material, environmental and cultural aspects of the city. This paper aimes to analyze arboreal rows in HALAB Street and to study their relation with the service and structural engineering components Of that street . Moreover, the optimal situation of these street trees was evaluated using (Li et al, 2011) equation.Results of this paper revealed prominent breaks in the arboreal rows, and that these rows contain four tree species (Jacaranda mimosaefolia Don., Ficus nitida L., Eucalyptus rostrata S., Melia azedrach L.), which served to furnish the street with monotonic beauty and humility in botanic diversity. Findings showed decrease in the optimal value of the two used botanic species where (Jacaranda) attained a mark of 6.22/10 and (Ficus nitidia) 7/10 and (Eucalyptus) 7.28/10 and (Melia) 7.53/10. Corresponding to the relation of trees to some street engineering elements, results indicated inobservance of standard dimensions between planted trees and service elements. which negatively influenced the aesthetic and position value of buildings’ and stores’ facets and guiding signs and billboards on the one hand, and risk increase on pedestrians and vehicles due to blocking vision of traffic signs and overlap of tree crowns with electricity and lighting posts on the other hand.