Selecting Trees for Shade in the Southwest    (View PDF)

E. Gregory McPherson and Eileen Dougherty

Abstract: Shade trees in the Southwest can provide large potential energy savings for cooling and enhanced comfort for outdoor living. However, water costs for shade trees may offset space cooling savings in water-scarce regions. Computer simulation was used to calculate potential residential heating and cooling savings from several shading scenarios in Tucson, Arizona. Energy savings were compared with water costs to derive net savings for six tree species commonly used in Southwest landscapes. Dense shade on west walls reduced annual energy costs by 10-12% ($55-121), depending on the type of building construction. A surprising finding was that tree form appears to have a greater effect on energy savings than crown density and, hence, merits more attention during the tree selection process. Annual water costs were equivalent to about 20% of annual energy savings for low-water-use species and ranged from 53-261% for the high-water-use species. Water requirements are an important factor to consider when selecting shade trees for Southwest landscapes.

Keywords:

https://doi.org/10.48044/jauf.1989.009