Current Articles
Browse Archives
Contact Us
AUF Home
ISA Seal
Get Acrobat Reader

Arboriculture & Urban Forestry Online
Volume 39, Issue 4 — July 2013

A Comparison of the Shading Effectiveness of Five Different Street Tree Species in Manchester, UK    (View PDF)

David Armson, Mohammad Asrafur Rahman, and Anthony Roland Ennos

Abstract: One major benefit of urban trees is the shade they provide on sunny days; this reduces the heat stored in engineered surfaces and lowers the heat load on people, increasing their comfort. This study compared the shading effectiveness of five small street tree species within the urban landscape of Manchester, UK. The area of shade produced by each tree during early and midsummer 2012 was calculated from morphological measurements, such as canopy height, width, and aspect ratio. The effect of tree shade on air, mean radiant and surface temperatures was also compared and related to the leaf area index (LAI) of the canopy. It was found that tree shade reduced mean radiant temperatures by an average of 4C, though neither tree species nor LAI had a significant effect. Tree shade reduced surface temperatures by an average of 12C, and the tree species and LAI both had significant effects. Tree species with higher LAI, Crataegus laevigata and Pyrus calleryana, provided significantly more cooling than the other species, and surface temperature reduction was positively correlated with LAI. This study has shown that trees are useful in improving both human thermal comfort and reducing surface temperatures in urban areas, and that selection of tree species with high LAI can maximize the benefits they provide.

Keywords: England; Human Thermal Comfort; Manchester; Mean Radiant Temperature; Surface Temperature; Tree Shade; United Kingdom; Urban Heat.

Current Articles | Browse Archives | Search | AUF Home | ISA Home | Get Acrobat