Street Trees

Article

Most of the photos of great streets seen on these pages feature street trees. Trees are among the most important – and overlooked – features of urban streets. Visual preference surveys routinely reveal that citizens greatly prefer streets that feature mature canopy trees and other vegetation to streets that do not.

Benefits of Street Trees Include:

1. Reduced heat absorption. Paved streets and urban parking lots can increase localized ambient urban temperatures by 3 - 7 degrees, significantly impacting energy consumption and energy costs for homeowners, business owners and consumers.

   Credit: LGC Households in well-shaded neighborhoods with urban street trees can experience energy savings of 15 - 35%.

2. Traffic calming. Properly-placed street trees frame and define the street as perceived by drivers. The vertical edge to the view plane that the trees provide reduces the apparent width of the street, increasing “friction” and lowering average speeds.
3. Placemaking. Trees create identity, increase attractiveness and provide framing for plazas, seating areas, and sidewalks. The spatial definition added by trees helps create memorable spaces within what would otherwise be featureless sidewalks.

4. Property values. The attractiveness, heightened identity and placemaking effects of mature, well-placed street trees combine to add value to abutting properties.

   Credit: Charlier Associates In some cases, the added property tax proceeds from increased valuations may recoup much of the cost of installing and maintaining the trees.

5. Pavement preservation. The shading of pavements by street trees increases pavement life, reducing long term costs of street maintenance.

6. Reduced storm water run off. Street trees can significantly reduce the percentage of rain water that reaches the ground below them. The actual percentage is greater for light rains and is highest during the early stages of extended rain events.

   Credit: Walkable Communities While this may not reduce the size of required street drainage systems, it does reduce the total amount of storm water delivered into street drainage systems over the course of a typical growing season.

7. Improved air quality. Trees absorb carbon monoxide and other air borne pollutants.
8. Intangible public benefits. Although difficult to measure, the public reaps significant benefits from the improved attractiveness and shading of public streets that street trees provide.

Resources

PDFs:

• 22 Benefits of Urban Street Trees

Other References:

• Tree Guidelines for San Joaquin Valley Communities, by E. Gregory McPherson, James R. Simpson, Paula J. Peper, QingfuXiao, Western Center for Urban Forest Research and Education, Published by the Local Government Commission.
• “Effects of Street Tree Shade on Asphalt Concrete Pavement Performance,” E. Gregory McPherson, Jules Muchnick, Journal of Arboriculture, November 2005.