Urban trees as sunlight control elements of vertical openings in front façades in sunny climates. Case Study: Morus alba on north façade

Abstract

Benefits of urban trees are evident from the energy and environmental perspective, likewise they reduce glare and control light intensity. Given the hypothesis that trees reduce visible radiation significantly reaching lower level façades, this study is an approach to the analysis of urban forestation as a solar control element. The methodology employed involves measurement of: illuminance – transmittance variation, permeability variation and luminance contrast, by levels along the vertical development of the tree. Vertical illuminance values that exceed 25,000 lx were detected from 5.5 m onwards and values inferior to 3500 lx under that height. Based on the daily analysis of mulberry trees permeability variation in the visible spectrum, it is noted that incident radiation decreases by 90%, with 15% of variability. Natural light analysis must be differentiated by height since daylight scenarios vary accordingly.

Accommodating a tree asset register of street trees in a local government authority setting

“…Trees may make it difficult to detect criminal behaviour (Lyytimäki and Sipilä, 2009) even though there is evidence urban trees are associated with less crime (Troy et al , 2007). Street trees may block sunlight, although it may be argued they may be used as a form of sunlight control (Villalba et al , 2016); tree-shading may also protect bitumen (McPherson and Muchnick, 2005). In addition, street trees may be destructive causing damage to physical structures which break up pavements, and tall trees may cause maintenance problems (Lyytimäki and Sipilä, 2009).…”