The 65-foot-tall tree lives in the middle of an easement at 827 15th Ave. designated for a pipeline meant to carry water from the Hetch Hetchy as part of a $4.6 billion seismic improvement project.
During a meeting on June 30 with a coalition of neighbors fighting to save the tree, the commission proposed tunneling under the oak tree — if the coalition agrees to form a 501c3 nonprofit to care for Granny.
The tunnel comes with an estimated $300,000 price tag. "It would be a gift of public funds to spend money on this tree to benefit the individual homeowner and adjacent neighbors," said SFPUC spokesman Tyrone Jue. "By creating an open publicly accessible area, we create a public benefit whereby anyone can enjoy the tree and space."
The nonprofit would assume all liability for the tree and would also have to allow public access. The neighbors said they aren't comfortable with that option yet. "There's going to be pushback on this," said coalition member Ron van Thiel. "Definitely pushback."
Fellow tree advocate Mary Ann Mullen described the meeting as very unsatisfactory. An arborist working on behalf of the coalition suggested digging a modified trench instead of a tunnel, but Ms. Mullen said the commission refused to consider it.
"The bottom line is that they just don't want to do this option," she said. "They rejected it without discussing it with us, without responding to us. Basically, they've closed the open door process."
Mr. Jue told the Almanac that the SFPUC discarded the modified trench option because it doesn't leave enough space between the tree roots and the pipe, which increases the risk of pipeline failure, and that beams needed to buttress the trench would endanger the tree's health and stability.
An exploratory trench dug in June showed the tree's roots extended 28 feet to two pipelines already installed in the ground, according to Mr. Jue. He said the commission can trim the roots back three feet, and install a protective plate to prevent them from reaching the pipes again.
The next meeting between the coalition and the SFPUC is scheduled for July 13.