"I rafted down with several old forest workers to record their work songs. At the beginning, the raft was floating gently down the river. However, when it floated to a place called Threshold Post, a big wave hit us and suddenly threw me into the current," Cao said.

He couldn't swim and fought to survive in the waters. His notebook with more than a week's worth of notes also flew into the water and was soon floating away.

By the time the workers pulled him to the riverbank, he had already lost consciousness.

The old workers recalled that even while Cao was struggling in the water, he shouted to rescue his notebook first.

"You know it's not easy to have people in their 80s or even 90s recall the things that happened and clearly repeat work songs for you. Their health deteriorates and memory fades quickly. So the notebook where I recorded their words in some sense is unique. They trusted me, and I couldn't let them down," Cao said.

Thanks to his effort, the Changbai Mountain forest workers' songs were later listed as Jilin provincial heritage culture.

"Some of the old inheritors of folk culture that I had interviewed have already passed away and so these notebooks are priceless to me, for whenever I open them, their images will come to life in my mind and bring me back to the episodes," said Cao, who is also deputy president of the Jilin Provincial Folk Literature and Art Society.

Cao hopes the stories and songs will not be forgotten, so people in the future will be able to enjoy them.

Based on his notes, he has published more than 80 books featuring various endangered folk cultures.

The born storyteller has also earned the nickname of "story king of the Northeast".

To earn the trust of the interviewees, Cao always shows up during festivals when they are usually at home and in a comparatively amiable mood.

"Each festival, especially Lunar New Year, is a time of family gatherings and holiday meals. Everybody runs home, but I know one person who doesn't. That person is Cao Baoming," said Feng Jicai, president of the Chinese Folk Literature and Art Society, who has been Cao's friend for more than two decades.

"If our country had more people like Cao, we could rescue more traditional culture."