Seattle should do much more to save and increase its urban tree canopy, the city's auditor says in a report. It lists a number of issues with current tree management and suggests solutions, including better cooperation among city departments, more community outreach and increased protection of trees on private property.

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Seattle should do much more to save and increase its urban tree canopy, according to a report presented to the City Council on Monday.

The Office of City Auditor lists a number of issues with current tree management and suggests solutions, including better cooperation among city departments, more community outreach and increased protection for trees on private property.

City officials have said they’re addressing the problems, and point to recent increases in tree-canopy coverage.

Urban trees help reduce stormwater runoff and capture and store carbon dioxide, a greenhouse gas, said Soo-Hyung Kim, an assistant professor at the University of Washington College of Forest Resources. The trees also can help conserve energy by providing shade and blocking wind, he said.

The city announced an ambitious goal in 2007 to increase its urban tree-canopy coverage from 18 to 30 percent within 30 years. The City Council requested the audit to review the progress of that plan and see how trees are being managed.

Seattle has identified trees as a priority, but its approach to managing trees isn’t centralized or orderly, the report says.

The city hasn’t been able to provide the funding that agencies say they need to maintain and protect trees, the audit says.

It also says a thorough inventory of Seattle’s trees hasn’t been completed. Many of the trees are on private property, and single-family lots provide the most space for new trees to be planted. But public education and outreach is lacking, the report says.

The city is addressing the management issues raised by the audit and is moving forward on public outreach, education and other recommendations, said Michael Mann, acting director of Seattle’s Office of Sustainability and Environment.

A consultant recently used advanced satellite images to examine Seattle’s tree-canopy coverage, and the data shows it’s actually closer to 23 percent, Mann said. The 18 percent canopy figure comes from a study in 1996.

The city has planted nearly 1,600 new trees in the last two years.

Still, some council members say Seattle hasn’t done enough to protect its trees and has neglected to involve a broad group of stakeholders in the tree-management process.

Councilmember Nick Licata has proposed creating a commission of neighbors, city officials and forestry experts, among others, to make recommendations on urban-vegetation issues.

Council President Richard Conlin said he will push to finish by November an ordinance to protect existing trees by limiting the number that can be cut on private property, and providing incentives to developers and homeowners to not remove trees.

“Trees are so important to our city,” Conlin said. “We need to do a lot to really have the kind of tree canopy we need.”

The city has plans to plant nearly 650,000 trees to meet its 30-year goal. The city has estimated it would cost $114 million to plant them. A greater effort should be placed on saving old trees, because their canopies and leaf-surface area trump that of many young trees, said Rob Gala, a spokesman in Conlin’s office.

Michelle Ma: 206-464-2303 or mma@seattletimes.com