Palo Alto famously loves its trees, particularly when they're not toppling onto roofs, yards and power lines.

But with residents raising concerns about the city's recently adopted tree-protection ordinance, the City Council signaled Monday that it is preparing to re-evaluate the law and consider giving residents more flexibility when it comes to removing trees on their properties. This could include allowing residents to remove trees that are deemed "protected" in exchange for planting more trees elsewhere on the property or on another site, several council members suggested.

Any such changes are still months away, with the tree ordinance set to go for a re-evaluation in front of the Planning and Transportation Commission and the Parks and Recreation Commission before returning to the council.

They are also unlikely to go unchallenged. Several tree advocates who are council members, including Vice Mayor Greer Stone, argued that the new tree-protection ordinance is rather tame compared to laws in surrounding jurisdictions. He supported keeping the law in place, particularly given that the city has yet to fully implement some of its educational and outreach components.

"This is just not an extreme ordinance, despite talking points by some," Stone said. "This really is a product of substantial community involvement."

But after hearing complaints from residents whose homes were damaged by trees during last winter's storms, some council members said they believe it's time to address these concerns. Leah Russin, who lives in Barron Park, recalled to the council the fear that she and her 3-year-old daughter experienced last winter when a giant tree in their yard fell on their house during a storm, puncturing the roof, the attic and the ceiling of two floors of the home.

While city law allows removal of trees that are deemed dangerous or that are causing damage, it requires a statement to that effect from a certified arborist before the permission is granted. Russin believes that's a key flaw and noted that in her case, the certified arborist that inspected the tree prior to its collapse saw nothing wrong.

"It unreasonably demands that residents assume the unknowable risk of whether these trees are healthy," Russin told the council. "Reliance on arborists is misguided."

The ordinance, which the council approved a year ago, roughly triples the number of trees that are deemed "protected" and, as such, cannot be removed without a permit. According Peter Gollinger, the city's urban forester, the number of such trees has increased from about 82,000 to 224,000.

The ordinance adds four new species to a "protected species" list that previously included only the coast live oak, the valley oak and the coast redwood but that now also includes the bigleaf maple, the incense cedar, the blue oak and the California black oak. All of these species, other than the redwood, would now be deemed "protected" when their diameter is at least 11.5 inches.

More significantly, the ordinance also mandates that trees of all species become protected when their diameter reaches 15 inches (for the redwood, the threshold is 18 inches). It was this requirement, Gollinger said, that is mostly responsible for the sharp increase in the number of protected trees.

Gollinger said that in the first 10 months since the ordinance was adopted, the city has seen 66 applications for tree removals not related to new developments, up from 36 over the same time period in the prior year and from 44 the year before. He noted that this year was highly unusual, given the heavy storms that the city had experienced. Thanks to storm damage, staff had responded to 243 limb failures during the first three months of this year, whereas they typically respond to about 250 over the course of the entire year.

"Four of the top 20 recorded peak flows on the San Francisquito Creek happened this winter," Gollinger said. "That's just mind-boggling."

In defense of the current ordinance

Supporters of the ordinance urged the council Monday not to make any changes to the new law. Former council member Tom DuBois, who served on the council when the ordinance was adopted, cited in a letter the "negative press" that followed the winter storms and acknowledged that the tree damage was "shocking, dangerous and sad to see." Other cities, he noted, had similar impacts and worse.

"However, we need to keep severe weather in perspective and not point to this rare event as justification to weaken a very reasonable ordinance," DuBois wrote.

Parks and Recreation Commission Chair Jeff Greenfield, who was heavily involved in drafting the new ordinance, also argued against making many major changes to the law, which he said will have a significant positive benefit for the local canopy.

"It is unfortunate that we suffered an extreme weather event, not to discount the significant losses that were incurred, but let's stay the course here," Greenfield said.

Competing issues at play

But at least four council members indicated that they would be open to revising the ordinance. Council member Greg Tanaka raised concerns about liabilities that the city would incur if it failed to grant permission to remove a tree that then caused damage to a resident's property. He also suggested that the city's fee of $500 for a tree-removal application is too high for some residents.

"Not everybody in Palo Alto is rich," Tanaka said. "We have to be very conscious of that and make the process more streamlined."

Gollinger noted that existing rules allow the city to give immediate verbal permission for tree removal in cases where a tree might pose a hazard. But for some residents and council members, the complications of dealing with hazardous trees isn't the only problem. Another is the potential of protected trees to prevent construction of accessory dwelling units (ADUs) and other types of housing.

Resident John Kelley, a housing advocate, suggested that the new tree ordinance aimed to solve a problem that didn't exist and argued that it clashes with state law when it comes to accessory dwelling units. Council member Julie Lythcott-Haims requested more information about cases in which property owners requested a tree-removal permit as part of a plan to construct housing, whether through a new ADU, a junior ADU or a Senate Bill 9 lot split.

She supported exploring a change that would allow tree removals in those cases, provided the property owners plant even trees elsewhere.

"Maybe there's a way to make a meaningful exchange, so we don't just retain a number of trees, we might get more, but we're also able to meet our housing goals at the same time," Lythcott-Haims said.

Council members Pat Burt and Vicki Veenker also said they would support more flexibility in the city's ordinance. Veenker cited Russin's experiences during the last storm season and suggested that the city's rules include provisions to address trees that may not be causing damage at the moment but that may pose an imminent risk to the property owner.

"We're going to have to grapple with this balance more directly," Veenker said. "Having a good canopy … is very important to our climate plan, but that doesn't necessarily mean that the trees that form a canopy have to be static."

Burt similarly emphasized the value of the city's canopy but cautioned against adopting an "absolutism" approach on tree protection. He suggested that the city's approach to canopy protection should focus on its most important heritage trees, such as mature valley oaks, rather than have one rule for near all trees with a diameter of 15 inches or greater.

In addition to issues with accessory dwelling units and hazardous trees, the ordinance also creates daylight issues for some residents who may want to grow gardens in their yards but cannot because of the canopy, Burt said.

"I don't know the correct balance but I know there are competing issues," Burt said. "We kind of emphasized one half of the equation but there are other things on the other half of the equation.

"I think the net result will be that we'll continue to embrace policies that will continue to increase our canopy, no matter what tweaks we have. How much and how we trade off the other things is what we're struggling with," Burt said.

Not everyone was as gung-ho about changing the ordinance. Council member Ed Lauing suggested that the city ramp up its outreach and education efforts to ensure residents are aware of all the new rules. And Mayor Lydia Kou rejected the idea of having small, newly planted trees replacing large established ones.

"Looking at baby trees -- planting numerous of them -- is never comparable to an older tree that has matured and that is doing a lot of carbon sequestration work," Kou said.