Effect of the Pattern of Tree Planting on Quantitative and Qualitative Characteristics of Elm in and Urban Area

The 16th district of Tehran city was selected for investigating the condition of trees in urban areas. A qualitative and quantitative study was conducted on the stands of two species, namely European elm (ulmus carpinifolia) and Persian elm (ulmus carpinifolia var.umberaculifera), in two forms of stand and line. One hundred trees for each kind (separately) were measured after selecting the stands. After having chosen the lines, first one tree was randomly selected and, then, the next tree would selected and the fourth one. Following this, quantitative parameters (including diameter at breast height, tree height, crown height and average of crown diameter) and qualitative parameters (including the health of crown, the die back, canker, and pests and multi-branching) were measured. According to the results we can say that, according to quantitative characteristics, the European elm has a better desirability rather than the Persian elm, while the Persian elm has healthier crown, lower die back and fewer pests than the European elm in terms of qualitative characteristics; the European elm has more limited multi-branching than the Persian elm but no significant differences were discovered in canker. Thus, for the development of green areas in lines and where the objective is to design an aesthetic landscape, it is better to use Persian elm and, when establishment of forest planting and improvement of quantitative characteristics is desired (stands), European elm may be a better option.