Mature Trees Significantly Reduce Energy Use in Urban Areas

By Michelle Sawka, Andrew A. Millward, Janet Mckay, and Misha Sarkovich

Toronto, ON (May 29, 2013) – New research that assessed the energy conservation merits of a residential Toronto tree planting program found an average tree conserves 435-483 kWh of electricity over 25 years post planting. Research findings also indicate that densely settled urban neighborhoods should prioritize tree survival over shading potential, as the energy conservation benefits of a mature tree often outweigh the benefits of a strategically planted one.

Tree lined streetResearchers adapted the Sacramento Municipal Utility District’s (SMUD) Tree Benefits Estimator for application in Toronto, Canada. They then used the tool to model the air conditioning energy conservation savings delivered by 577 trees planted Toronto backyards between 1997 and 2000.

In urban residential urban residential neighborhoods, where houses are closely spaced, the energy conservation benefits of planting a tree depend on species, on pre-existing canopy, and on placement of the tree with respect to distance and orientation from buildings.

Study trees contributed 77,140 kWh (167 kWh/tree) of electricity savings as of 2009, 54.4% of which was due to shading of neighboring houses. On a per-tree basis, these savings are equivalent to the amount of electricity needed to run an average Canadian home for about a week (assuming household use is approximately 25 kWh per day).

Twenty-five years following planting, researchers estimate that each study tree will have delivered, on average, between 435 and 483 kWh in energy conservation benefit. This can translate into a saving of upwards of $40 annually.

Findings indicate that residential tree-planting programs in densely settled urban areas should not focus exclusively on location-driven strategic planting to yield large energy conservation benefits. Instead, the researchers argue that priority should be given to selecting planting locations that will maximize tree survival as neighborhood energy conservation benefits of a tree that achieves mature stature often outweigh the homeowner-specific benefits of a strategically planted tree.

In addition to energy savings benefits, the Ryerson University-led study also outlined the ways trees improve the environment. Trees also provide environmental benefits such as reducing air pollution, providing a natural habitat for wildlife, sequestering carbon dioxide from the air and mitigating storm water runoff.

The study, “Growing Summer Energy Conservation through Residential Tree Planting,” was published in the May issue of the journal Landscape and Urban Planning.

Related Resources
Growing summer energy conservation through residential tree planting
Planting a tree will significantly reduce your summer energy bills and improve the environment: Ryerson University-led study