California Highway Patrol has completed its investigation into the Feb. 20 fatal crash on State Street in Columbia and determined the driver, Eugene Cummings, died of a heart attack before striking the tree.
Cummings, 68, was driving home when the accident happened.
He was heading west on State Street at a high speed in his 1997 Chrysler LHS about 1:20 p.m., the CHP said.
His car went off the south edge of the roadway, where it sideswiped a tree, ran over a row of mailboxes and a hit a large pine tree head-on, the CHP said.
A witness and others passing by provided medical aid until emergency personnel arrived on scene.
The CHP said Cummings wasn't wearing a seatbelt at the time of the crash.
He was pronounced dead at Sonora Regional Medical Center.
Zane's Iron Horse Lounge in Sonora on Saturday held a potluck to commemorate the bartender, who went by "Gerry."
"He was a figure around here," said Terri Fowler, who works at Zane's. "Even on his days off he'd come in and visit."
Fowler said Cummings had tended the bar for about five years and had many regulars.
She said he loved to discuss politics and "wine and dine." He had a degree in hotel and restaurant management from San Francisco City College.