Investigating the Planting Pattern Based on Desirable Visual Scale in Neighborhood Parks (Case Study: Neighborhood Parks in Districts 18 and 1 of Tehran)

Neighborhood parks play an important role in the relationship between people and the nature. In fact, vegetation and planting are the most important motivations for attendance of and recreations available in parks. For improvement of the quality of green spaces in neighborhood parks and enhancement of public participation, it is necessary to design the park landscape with respect to people’s preferences and their perceptions of the desired landscape, while there are some shortcomings in this regard. Therefore, the purpose of this research was to investigate people’s visual preferences in order to optimally design vegetation in neighborhood parks. A neighborhood park is a small green space (about two hectares large) with a penetration radius of about one kilometer, and it is readily accessible on foot from residential areas. The present research aimed to study these preferences in the field of spatial configuration of vegetation based on a visual scale. The visual scale is an important, effective feature in the creation of confinement and control of visual access. In this study, the underlying factors of age, gender, and socio-economic class differences were considered. Due to the difference in economic level in the northern and southern regions of Tehran, neighborhood parks in these two regions and their users were selected for evaluation. Five neighborhood parks in each region were considered purposefully.

The method adopted in the present research was a combination of the qualitative and quantitative approaches. First, the spatial configuration of vegetation in the creation of different types of visual scale was investigated, and five categories of visual scale were identified. Images were provided of the vegetation compositions of neighborhood parks with high income levels (region 1) and low income levels (region 18). After consultation with the elite, the images were categorized based on a variety of visual scales. The visual questionnaire consisted of two images for each visual scale, where landscape desirability was examined with a Likert scale. Using random sampling, 363 people who visited neighborhood parks in the two areas of Tehran (District 1 and District 18) completed the questionnaire. The data were analyzed using the Bonferroni post hoc test in SPSS. After their collection, the homogeneity of variance was first examined through the Levin variance homogeneity test for comparison of the user preferences in terms of the type of landscape, and the results demonstrated that there was no significant difference between the variances of the variables in the groups (PS ˂ 0.05). Therefore, one-way analysis of variance was used to compare the studied variables between the groups, and the Bonferroni post hoc test was used to control Type I error if there was a significant difference between the opinions.

The results of the present research indicated that there were different visual preferences for the images. Thus, the closed visual scale and open visual scale between all the groups were undesirable, as well as the semi-open visual scale and open visibility under canopy landscape between all the participating groups. Among the studied underlying factors (difference in the income levels in the regions, age, and gender), gender exhibited little effect on the formation of the landscape preferences, and women preferred more enclosed landscapes.

The results of this research demonstrated given the desirability of semi-open images that the spatial configuration of vegetation formed through planting and pruning should not allow for any visual barrier in the foreground layer while planting at the observer’s line of vision is obstructed in the background layer and sporadically in the middle layer. Moreover, it is desirable for plant height to be less than the observer’s line of vision and for tree canopies to be placed at heights greater than the observer’s visibility in the background layer. Due to the desirability of open visibility under canopy images, it is possible to provide favorable climatic conditions through selection of a combination of canopy umbrella trees of two types, fallow and non-fallow, which also allows for wide visual access. Due to the unfavorable landscape of the closed view, it is not appropriate to practice such planting at the observer’s line of vision in the foreground layer of the view. It is also necessary to avoid open visual scale design, where the coating exhibits low density in all the three layers. Regarding the influence of underlying factors, it can be stated that the landscape preferences for optimal visual access were almost the same for the different groups, but the women were more inclined to prefer semi-open visual-scale images due to the need for privacy and security, and images with closed vision were less favorable for them. Thus, the proposed species could be proposed given their heights for all the three layers of foreground, middle ground and background, according to the obtained patterns. The present study took the first steps in landscape planning based on awareness of public preferences, and these findings provide practical solutions for landscape planting design.

This article has been taken from a doctoral dissertation entitled Promoting Cultural Services of Urban Green Spaces Based on the Visual Assessment of Landscape: A Case Study of Urban Parks in Tehran, developed by the first author under the supervision of the second author and the advisory of the third author in the Faculty of Art of Tarbiat Modares University. The dissertation has enjoyed financial and spiritual support from the Tehran Urban Research and Planning Center as a research project.