For years, San Francisco residents have groused about taking care of street trees and paying for the costly sidewalk damage they can cause — projects they never wanted. But four city supervisors have proposed three pieces of legislation that would return those tasks to the city, and soon.

There’s a parcel tax, which would have to go to the ballot, that would dedicate more than $18 million annually to trees and sidewalk repairs beginning next July. It would also return tree maintenance to the city — it’s now the responsibility of homeowners and businesses. Then there’s a bundled charter amendment and carbon tax designed to bring in $18 million to take care of trees. The third is a proposed ordinance that would transfer the maintenance much sooner — but without any earmarked funding.

But, while the renewed focus on trees is welcome, the most viable option comes down to dedicated funding, said Carla Short, an urban forester for the city. She’s been pushing for more routine tree maintenance since 2008, when supervisors slashed the budget.

“Trees are the workhorses of our infrastructure,” Short said. “They need a dedicated funding source for maintenance. Routine annual allocation? That has never worked.”

The city began transferring the ownership and upkeep of its trees to homeowners in 2011 after the recession cut into the city’s budget. That incensed residents, who often don’t have the cash for costly pruning and associated sidewalk repairs.

Under a parcel tax introduced by Supervisors Scott Wiener and Eric Mar this spring, those duties would be transferred back to the city beginning July 2017. The ballot measure, which goes back to the supervisors for a final vote Tuesday, would fund tree maintenance with a combination of a progressive property tax — one that increases with the property’s size — and an $8 million annual budget set-aside for a total of $18 million to $19 million. The average resident or business would pay about $35 annually.

Funding concern

“We have an unfair system that dumps responsibility on property owners to take care of the trees and fix the sidewalks,” Wiener said. “I could have introduced legislation five years ago to require the city to take back the trees. I could have done that. But it’s not fixing the problem. If we take them back without sustainable funding, the trees will simply die.”

He was referring to legislation introduced by fellow Supervisors John Avalos and Norman Yee this month. Avalos’ measure goes to the board on Tuesday, and Yee’s is headed to a Board of Supervisors’ committee.

Avalos’ measure is also designed to bring in $18 million by taxing natural gas — adding about $2.70 to a household’s monthly bill. But that carbon tax would only funnel money into general fund reserves, meaning there’s no guarantee it would actually go to fund trees. The amount is also expected to drop to $10 million in coming years as residents switch to green energy programs, like CleanPowerSF.

“I have a concern about too many revenue measures going to the ballot,” Avalos said, referring to a November ballot full of proposed tax raises. “We don’t have enough funding to grow the urban forest, which is a goal (Supervisor Wiener and I) both have. The carbon tax could also help with that. I expect we will have a solution, whether that’s a measure by Yee, Wiener or me by the end of the month.”

Yee’s proposal

Tree advocates who have fought to improve the city’s canopy say the least-attractive option is Yee’s. The ordinance, if passed, would transfer roughly 105,000 street trees back to the city within one month. Public Works now cares for 26,500 trees. About $3 million to $4 million from the general fund’s rainy day reserve could help fund that transfer, Yee said.

“It would punch a big hole in our budget,” Public Works spokeswoman Rachel Gordon said. “It would reassign all responsibility for trees and sidewalks without identifying any additional funding. We have a finite budget, and this would stress it.”

But Yee said that the city shouldn’t wait until November and that additional funding could come later.

“This is not a new concept,” he said. “It’s going back to an old concept. It’s great to have new revenues, but we need to make a decision now with general fund money. We shouldn’t have to wait until this fall.”

Whatever happens, at least the trees are finally back on the agenda, said Dan Flanagan, director of Friends of the Urban Forest, which helps residents plant and maintain trees in the city.

“The bottom line is that the supervisors are talking,” he said. “I think they will come up with a solution amongst the three of them that will solve our problem. The trees will finally have a well-thought-out plan.”

Lizzie Johnson is a San Francisco Chronicle staff writer. Email: ljohnson@sfchronicle.com Twitter: @LizzieJohnsonnn