County May Require Use of Shade Trees

Taking a cue from Johnny Appleseed, the Board of Supervisors voted Tuesday to review the increased use of trees in new parking lots as a way to cut down on pollution.

At the board’s direction, the Regional Planning Commission will study the feasibility of requiring shade trees in public and private parking lots. The commission must return its recommendations to the board within 90 days.

A study by the U.S. Forest Service suggests that the shade provided by trees reduces evaporative hydrocarbon emissions from parked cars by lowering temperatures. Increasing the leafy canopy coverage to 50% could moderately reduce vehicular emissions. Parking lots--urban pollution hot spots--take up an estimated 10% of cities, researchers said.

“It’s time to take a hard look at the county policy on canopy cover. We were astounded that parked cars accounted for that much pollution,” said Cam Currier, spokesman for Supervisor Mike Antonovich, who rushed the motion onto the agenda Friday.

The city of Los Angeles has a 2-year-old ordinance requiring tree shade coverage of 50% over a parking lot within 10 years. Currier said a similar requirement may be in the works for public and private lots in the county. Planning officials could not be reached for comment on existing ordinances.

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Environmental groups applauded the decision to study such a requirement, saying it could help clean up air and protect public health.

“It’s fantastic,” said Andy Lipkis, president of the group TreePeople. “It’s a win-win situation, provided that the proper trees are selected--trees with the right amount of shade that don’t break up asphalt or drop sticky things.”

TreePeople met last week with representatives of the Forest Service, the City Council, three other tree groups and public agencies such as the Department of Water and Power. Those discussions prompted consideration of planting projects for parking lots at the Los Angeles Zoo and at schools in the Los Angeles Unified School District, Lipkis said.