SAN FRANCISCO (Map, News) - Marilyn Rodriguez says she thought it was a gunshot she heard Monday morning as she walked her dog Benson in Stern Grove, but she quickly realized it was the cracking and collapsing of a branch.

In a freak accident, a woman was killed Monday when a 50-foot redwood tree branch fell upon her as she stood in the Sloat Boulevard parking lot of the heavily wooded park.

“A car alarm went off, and then I realized what I heard was a branch,” said Rodiguez, a Sunnyside resident.

The partial tree with protruding branches damaged the rear of the car, a Subaru Outback, and lay across the woman’s body.

The victim was transported to San Francisco General Hospital, but doctors pronounced her dead at 12:14 p.m., San Francisco police Sgt. Wilfred Williams said.

The broken piece of tree appeared to be “a portion of the top of the tree and had branches coming off of it,” San Francisco Fire Department spokeswoman Lt. Mindy Talmadge said, estimating it fell 30 feet.

“This big section of the tree broke, came down and hit — crushed her car,” Talmadge said.

The official cause of the break was unknown, but she said it “was very windy out.”

The woman’s three dogs — two labradors and a Chihuahua-corgi mix — were uninjured and cared for by Animal Care and Control before a family member retrieved them Monday, Capt. Vicky Guldbech of Animal Care and Control said.

This was not the first incident in Stern Grove. Recreation and Park Department spokeswoman Rose Dennis said a city employee conducting tree work there died during a storm in 1981.

“Trees here shed branches from time to time,” said John Rossi, who has lived near Stern Grove his entire life and was walking in the park Monday afternoon.

Rossi was surprised at the news of a fellow hiker’s death, but doesn’t feel unsafe walking in the grove.

“That’s too bad — like being struck by lightning,” he said. “It’s just really unlucky.”

Vehicle access to the park will be denied until Thursday or until the department has “assured people and ourselves that it was a fluke,” Dennis said. “There’s nothing wrong with Stern Grove, but we need to make sure we’ve done our due diligence,” she said.

dsmith@examiner.com

Examiner Staff Writer Beth Winegarner contributed to this report.