by Jennifer Tso
Published February 2014
Plants in parking lots have been traditionally used for aesthetics and traffic guidance. Regulations generally mandate the quantity and distribution of plants, including trees, based on the size of lots. Increasing emphasis is placed on the ecological services and benefits of urban vegetation, a trend that can be seen in laws regarding parking lot trees. Davis, a small city about 20 miles west of Sacramento, California, was one of the pioneers of parking lot shade regulations. Davis’ ordinance requires that all parking lots be 50% shaded by tree canopy 15 years after development. Although the regulation has been in place for nearly 40 years, there are been no enforcement of shade coverage. The city partnered with Tree Davis to monitor parking lots in 2006 and 2007, but the project was terminated soon after due to budget cuts. In 2013, a Tree Davis intern revisited parking lot shade regulations in Davis as well as other cities in the U.S. The report titled “Parking Lot Shade Regulations: Review and Recommendations” is a summary of that work.