Managing the urban forest | May 20, 2011 | Palo Alto Weekly | Palo Alto Online |

Palo Alto Weekly

News - May 20, 2011

Managing the urban forest

New Palo Alto database helps arborists care for public trees

by Sue Dremann

If a tree falls in Palo Alto's urban forest when no one is around, will anyone know?

With the debut of the city's $156,894 TreeKeeper, an inventory of Palo Alto's estimated 36,000 street and park trees, the answer is, "Yes."

The database, completed by contractor Davey Resource Group in April, is a tool to help arborists manage the city's beloved trees. The program can locate and identify the species of every one of the city's publicly owned trees and track each tree's history and health.

At the click of a mouse, the program can give an aerial view of a street or show by color which trees are a priority for care.

The project was funded by a $120,000 California Department of Forestry and Fire Protection (Calfire) grant and $39,000 in city matching funds.

In the city's Municipal Service Center on East Bayshore Road, Eugene Segna, interim public-works managing arborist, recently demonstrated the new system.

"Prior to 2010, we didn't have mapping of publicly owned trees," he said. But the new system tracks condition assessments of each tree, including age, maintenance records, diseases and impediments such as overhead utilities that could impact the health of the tree. Trees can be ranked for replacement, pruning and pest control. The number of Palo Alto trees with pests: 175.

Condition assessments and maintenance records will be submitted to the council, he said.

Segna searched by address and pulled up records about a tree on the 800 block of Embarcadero Road. The record showed a Cinnamomum camphora located on the side of the house. Green dots indicate all trees in the area; yellow dots indicate trees currently being looked at. The database shows call history, work history, who did the work, when a tree is removed, the reason for the removal. In this case, the tree died, he said.

Another record can find vandalized trees and inspections for pest control.

Segna looked for trees listed for priority pruning — there are 379 in the city.

One feature includes adding comments and attaching documents. Segna checked out the condition of a magnolia on Edgewood Drive. Photos show the tree has extensive decay.

Another tree gets a "priority 1" to prune, while a third on Oregon Expressway with Dutch elm disease had to be removed.

A new feature also allows employees to see trees in relation to underground pipes and utilities. The tool can be used to plan for future layouts of sidewalks and streets, or to strategize replanting. The program can help limit damage to trees during sidewalk repairs, he said.

Segna tracks over time which species of trees are most likely to cause sidewalk lifting or damage. Throughout the city, 189 matches came up for high-priority hardscape-damage repairs.

The system could also be programmed for mobile use in the field, he said. Workers with computer tablets could call up tree records instantaneously as they drive through town, he said.

Segna can also track a tree's growth or if, for example, it has not grown after 10 years. Such information is useful in deciding if a tree should be removed, he said.

He searched for one of his favorite trees, snake bark maple (Acer capillipes). The city has 24.

Want to know which is the city's rarest tree?

"The city has a lot of one-of-a-kinds," Segna said, noting a single example of Eastern dogwood and just one Japanese red pine. These anomalies could have been experimental or could be plantings gifted from a horticultural foundation, he said.

Segna brought up a tree-frequency report. The city's top tree lives up to its name: Magnolia grandiflora — Southern magnolia — with 4,055 trees. It heads the list at 12.84 percent of the city's trees. Unidentified species in vacant sites: 2,051. And there are 272 stumps — just stumps — comprising 0.86 percent.

The new database, it is hoped, will help city arborists avoid costly mistakes such as the 2009 California Avenue tree-removal.

A January survey showed that residents want the city to improve managing street trees and improve making good choices about tree removal.

The database is a significant component in the development of a street-tree master plan, which the council requested in 2007, according to a March 15, 2010, City Manager's report.

That report also noted that Palo Alto's urban forest is changing. The tree population is aging, and development is increasingly disturbing city trees.

Palo Alto has two departments that utilize arborists: Public Works takes care of city-owned trees, and Planning and Community Environment oversees trees on private property. Dave Dockter is the managing planning arborist. Eric Krebs recently retired from Public Works.

Public Works is also going through a reorganization that includes the tree section. The proposed plan will be presented at a city budget hearing Tuesday (May 24), Public Works Director Mike Sartor said.

Staff Writer Sue Dremann can be emailed at


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