Sarah Swisher, of Kingsford Heights, died Saturday morning several hours after the freak accident.
According to LaPorte County police, she suffered a severe head injury.
Swisher was in the back seat of a 2005 Nissan Sentra that was northbound on Indiana 39 south of the LaPorte Municipal Airport just after 6 p.m. Friday, police said.
The driver, 37-year-old Charity Mitchell, told investigators she did not remember the accident but when she came to she was pinned in the vehicle.
The victim's husband, Sean Swisher, 44, told officers "all of a sudden it looked as though several branches were falling from the sky."
Sean Swisher also said the vehicle came to an abrupt stop and all of them were trapped inside the car, according to police.
He also said his wife, who was seated behind the driver, was not wearing a seat belt, police said.
The tree fell directly onto the driver's side roof of the car, police said.
Sean Swisher complained of pain to his chest and Mitchell complained of pain to her back.
Their conditions and whether they were taken to the hospital were not disclosed.
A wrecker was dispatched to the scene and lifted the tree off the car to allow all three of the occupants to be freed from the wreckage, police said.
The highway was closed in both directions for several hours to allow for an investigation and cleanup of the accident debris, LaPorte County Sheriff Mike Mollenhauer said.
The accident occurred along a heavily wooded stretch of Indiana 39, adjacent to Luhr County Park.
According to her obituary, Sarah Swisher graduated from the Art Institute of Chicago.
She attended St. John's Lutheran Church in LaPorte and loved to garden.
A celebration of life service will be held at 6 p.m. Thursday at St. John's Lutheran Church in LaPorte.
Numerous condolences describing Sarah as a "wonderful treasurer" and "very talented" were posted on her Facebook page, which included compliments about her being "sweet" and able to make people laugh.
"She was amazingly talented and had a smile that was infectious to everyone around," said Sacha Gee-Burns, a LaPorte resident and cousin of the victim. "She just had a way of making you happy."