The removal of 543 trees from the Palo Alto Municipal Golf Course could offer an opportunity to restore a portion of the Palo Alto Baylands to its natural state, the city's Parks and Recreation commissioners learned Tuesday evening.
A renovation and flood-control project would remove the equivalent of 6 acres of tree canopy from the course as part of the Golf Course Reconfiguration and Baylands Athletic Center Expansion Project. About 300 of them would be replaced.
The replacement trees would be smaller, native Bay Area species with less canopy, and it could take decades for the canopy to catch up to the level of environmental benefits offered by the trees standing today, according to a proposal report.
City staff presented the commission with three proposals for how to mitigate the tree removal, from replacing the trees in locations spread throughout the city to situating them all in city open space. The third proposal, a hybrid plan, would restore a portion of the Baylands to native wetland in addition to replacing hundreds of trees, Urban Forester Walter Passmore said.
Trees were not part of the native landscape to begin with, he noted.
The plan would net the city more than 800 trees to replace the 543 removed. In addition to planting trees at the golf course, some 500 saplings and seedlings at Pearson-Arastradero Preserve would be identified for focused preservation efforts, Passmore said.
Parks and Recreation commissioners were intrigued by the hybrid plan. It presents an opportunity to improve the wetlands while replacing the city's canopy, they said.
But commissioners asked for more data to understand how restoring the Baylands habitat would provide comparable ecological benefits, such as carbon offsets and other equivalents.
In accordance with formulas in the city's Tree Technical Manual, 2,000 young trees would equal the environmental benefits to the lost canopy of mature trees after 10 years of growth, Passmore said.
But costs could run to more than $1.3 million if all of the trees plantations are spread throughout the city. Staff would have to find spots for each individual tree. Costs could be reduced to about $200,000 if the trees are planted in large groupings in some locations, he said.
Another alternative was to forgo the Baylands planting and replacing only the lost canopy with native trees in historically forested areas, such as at Arastradero Preserve. But converting even part of the city's diminishing grasslands to forests would negatively affect grasslands flora and fauna, experts have said.
The undertaking would cost between $200,000 and $2.5 million, depending on whether the city uses new plantings, which require irrigation, or if already natural saplings at the preserve are protected, instead.
The proposed hybrid plan of 300 native trees in the Baylands and more than 500 saplings in Arastradero Preserve and marshland habitat restoration could cost upwards of $130,000, Passmore said.
"This one project in the golf course can establish a precedent of how we're going to treat the care of the Baylands in the future," he said.
Commissioners directed staff to return with more concrete data regarding the wetlands restoration so they can understand its environmental value. For example, each year, the golf course's mature trees today filter 1.1 million gallons of stormwater, while the hybrid-plan trees would filter 276,000 gallons after 10 years of growth. The trees would eventually catch up when mature, but that could take 40 years, Passmore said.
The report doesn't address how the marshland habitat restoration might influence those numbers, commissioners said.
"The importance of mitigating tree loss is a huge issue, and we will hear it from the community," Commissioner Stacey Ashlund said.
The plan would be an environmental improvement over the existing golf course, the report noted. It would provide greater resources wildlife, improved stormwater management, increased function of the wetland, and would reduce irrigation needs by about half, according to the report.
Commissioner Deirdre Crommie proposed a lump sum of $500,000 to address the hybrid plan rather than going for the bare minimum of $130,000.
"Here's a rare opportunity for us to really make an impact,"she said.
The commissioners did not vote on the proposal. A complete mitigation plan could come back for review sometime in January.