Urban Forest Master Plan looks to the future

Palo Alto plan seeks ways to balance the city's trees and conflicts

Named for a tree, the city of Palo Alto is challenged to sustain its urban forest in the midst of development and a changing arboreal canopy.

That was the message of Urban Forester Walter Passmore when he delivered a draft Urban Forest Master Plan to the Planning and Transportation Commission on Wednesday night.

The plan envisions a future forest that can meet the challenges of a changing environment and a rapidly developing city. Trees, so much the character of Palo Alto's past small-town look and feel, will play an important future role in maintaining the city's quality of life while making economic contributions in the hundreds of thousands of dollars, Passmore said.

But disparities between the north and south residential areas, increasing use of reclaimed, more salinated water, increased conflict between trees and solar installations and development will need consideration for the tree canopy to maintain its present and future continuity, according to Passmore.

"We need to be very innovative," he said.

Only seven of 96 species planted in the city are good street trees. The rest are fast-growing forest giants that are raising sidewalks and interfering with utilities. As the city replaces the trees over time, the master plan will use more adaptable species and techniques that avoid costly damage to infrastructure such as sidewalks and building foundations. When considering new plantings, the city would choose species that have a lower "thirst rating" for street trees to reduce water usage and cost, according to the plan.

The master plan analyzed tree benefits to the city in real dollars. The urban forest has a net benefit of more than $4.5 million -- $156.93 per tree -- for right-of-way trees alone when considering energy, carbon dioxide, air quality, stormwater and aesthetics, according to analysis.

The findings will shape the types of trees planted in the urban forest in the years to come. Some are better at reducing energy needs and sequestering carbon dioxide, the plan showed. Palo Alto's trees reduce carbon dioxide by a net 3,437.5 tons per year, at a saving of $1.77 per tree annually, according to the document.

Street trees alone also intercept 42,600,000 gallons of stormwater per year. As the trees mature, that number will increase, according to the plan.

Planning commissioners praised the document. But they suggested ways to strengthen its clout. Policy integration with the Comprehensive Plan and other city planning documents, enforcement and expansion of the city's tree-protection ordinance and developer requirements to maintain or replace trees should be clearly defined in the plan, they said.

"What is the greatest threat to our urban forest? As a public policy, it's urban development. I didn't see anywhere where we addressed a reaction or policy or program that addressed downtown development or development in neighborhoods," Commissioner Eduardo Martinez said.

A policy for urban development should include some responsibility of developers for the urban forest, he said.

Commissioner Michael Alcheck added concerns about conflicts between trees and the expansion of solar energy. The panels require direct sunlight.

Passmore is working with the city Utilities Department to figure out ways to have both, he said.

Commissioner Arthur Keller wanted a more refined analysis in neighborhoods, since the plan did not count neighborhoods that are part of commercial/residential areas.

Defining the city's canopy percentage and how it can be retained is also a goal.

Currently, thresholds for tree cover in the city are only recommended as guidelines for the city's Tree Technical Manual. They are not requirements in the zoning ordinance, Passmore said.

The plan should advise the City Council to consider changing the municipal code's tree ordinance regarding tree-cover requirements -- particularly for preserving or replacing trees when putting in new developments, commissioners said. The current tree ordinance protects certain species, including redwoods and two native oaks, heritage trees, trees of a certain diameter and so-called "designated" trees that are part of a development landscape plan.

The forest master plan will also rectify a disparity between north and south Palo Alto, where there is a 10 to 20 percent deficit in the tree canopy in southern neighborhoods. The difference emerged as a hot topic among 600 respondents to a community survey, the plan noted.

Original street trees throughout the city, and especially in south Palo Alto, were fast-growing, short-lived species planted to accommodate rapid residential growth. A post-World War II Federal Housing Authority requirement mandated a tree on every lot.

But while adding more than 2,000 trees per year to Palo Alto streets, those choices mean a decline and die-out of trees that has caused a void. Where street trees were replaced, they are too young to contribute to the canopy, the report noted.

Keller said he wanted to see a more refined analysis that includes commercial/residential neighborhoods so that no neighborhoods are excluded. Currently the analysis does not include commercial areas.

Ironically, development has increased the number of trees in the city, according to the plan. A 2011 analysis found the urban canopy cover was 32.8 percent in 1982, but 37.6 percent in 2010. Neighborhoods averaged 36.6 percent in 1982 and 41.1 percent in 2010. But where land is redeveloped, there was a net loss, the report noted.

City staff are developing a citywide "sustainability plan," which Passmore said provides an unprecedented opportunity to develop compatibility between the trees and other programs. He will incorporate the suggestions he has received from the Parks and Recreation and Planning and Transportation commissions. He expects to return to the planning and transportation commission in February for an endorsement of the master plan.


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Posted by rebugging
a resident of Los Altos
on Nov 15, 2013 at 10:33 am

I favor such planning in Palo Alto and other nearby cities. However, the story gives no link to the "suitable" and "unsuitable" trees and why they were so characterized. I think the allowance for solar is very important and seldom considered in choosing trees. Palo Alto has often been an environmental leader. Let's hope it continues now.

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Posted by Tree Lover
a resident of Duveneck/St. Francis
on Nov 15, 2013 at 12:02 pm

I have watched with dismay as the canopy in our neighborhood has been reduced year after year by the city's efforts to protect the overhead wires running through our backyards. Where pruning was once sufficient (albeit often done haphazardly by ill qualified subcontracts), it appears most of my neighbors have now been frightened into having their trees removed entirely, leaving us a new "canopy" of ugly poles and tangled wires. What happened to the plan to underground these wires? Was that only something for the toney areas of town? In our area, once the leafy canopy in Crescent Park was protected further undergrounding work stopped, never to return. I sure envy those big beautiful trees and fall color on my walks through Crescent Park. Wouldn't it be nice if all the neighborhoods in town had received the same attention? If we're going to talk about the value of a city wide canopy, let's talk first about finishing the work to underground wires in all, not just a few lucky residential neighborhoods, and let's pick up where the city left off years ago rather than allowing it to hopscotch the work all over town to the benefit of special interests rather than its ever-patient long term residents.

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Posted by Nora Charles
a resident of Stanford
on Nov 15, 2013 at 3:11 pm

Great comments, Tree Lover.

I still mourn the absolutely unnecessary clear cutting on California Ave.

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Posted by neighborhood advocate
a resident of Duveneck/St. Francis
on Nov 15, 2013 at 5:06 pm

As the recent election dramatically underscored, the priority of Palo Alto residents is to preserve the character and scale of our neighborhoods, which certainly includes the preservation of our urban forest. In recent years city planners have spent much more time granting building code exemptions for commercial and office development that has increased downtown density, traffic on residential streets, created parking problems, and resulted in a legacy of incredibly ugly architecture, than on solving problems that will improve our neighborhoods. Tree Lover's comments deserve a thoughtful response from our City Council and appropriate action from Public Works -- or more reporting from our local newspapers.

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Posted by Hugger
a resident of Old Palo Alto
on Nov 15, 2013 at 9:23 pm

In our neighborhood, they ever trim trees until a large branch breaks off and damages someone's car, and that person's insurance company demands repayment from the city.

For the last three years, we have complained to the city arborist about a dangerously dry and long branch that was in danger of breaking off and damaging any parked car underneath it. Earlier this year it finally broke and damaged someone's Prius. The car owner's insurance company sued, and a few months later, the city workers finally trimmed the tree we had complained about for so long.

Go figure

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Posted by resident
a resident of Another Palo Alto neighborhood
on Nov 15, 2013 at 9:57 pm

The City has no regard whatsoever for the aesthetic qualities of our
residential areas, doesn't care, doesn't relate to this. There is a long
list of issues in this regard. Needed ordinances and regulations are not passed and existing ordinances are not enforced. The over-building in the Downtown of course, with its own negative effects, has the spillover impacts on the already degraded residential areas. As for the trees, many are in very poor condition from drought and poor soil, also along arterials such as University Ave probably suffering as well from auto emissions from backed up traffic, and in some cases probably affected by dewatering from
nearby basement construction.

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Posted by Holistic sense
a resident of Green Acres
on Nov 17, 2013 at 1:32 am

Our City Council has all these grand ideas but they never walk the walk.

The orchard at Maybell has 100 established trees that seem fine without watering. Many neighbors felt the best use of that site was parkland, especially on this side of town that has faced so much densification, and at that site which so impacts the school commute corridors. It could be cultivated as a park like Gamble Garden House, but for trees. It's doable. As with Bol Park, we residents over here seem to have to pay for our parks ourselves, but we could do it if the City will give us the chance.

(Put the public money into saving Buena Vista - let the neighbors save the orchard, too.)

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Posted by David
a resident of Another Palo Alto neighborhood
on Nov 17, 2013 at 12:13 pm

Why all the bashing of the tree dept? These guys take pride in their work and work very hard. They have been pulled off of tree trimming a lot this year to plant a huge quantity of new trees. Without our normal fall rainfall, they are also taking time away from tree trimming to water these newly planted trees. With many of these quick growing trees maturing and coming to the end of their life span, many new trees need to be planted. Pull on your big girl panties and quit your complaining.

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