Sometimes, when sudden heavy winds or fog trapped them on the water, they would spend the night on their small boat, cooking fish they'd caught from the reservoir.

"We found ways to seek joy amid the hardship," Chen said.

By the numbers, the transformation is stark. The farm's forest coverage has jumped from under 30 to 92 percent. The volume of living trees has grown from less than about 25,000 cubic meters to over 100,000, according to Chen.

Li Guangyi, 59, was one of those who stayed.

"Back then, we were planting trees all year round," he recalled.

"Now, we mainly plant just once in March. The rest of the time, we just fill in gaps. Mass planting isn't necessary anymore," he said.

For years, Chen Renfan had a worry. His generation was aging out. Young people weren't coming. Who would watch the forest after they retire? He thought of his son, Chen Botao.

"When I was a senior in college, my father mentioned he hoped I would work at the farm," the younger Chen, now 36, recalled.

"I was young then. I didn't think that far ahead. I just felt this place was too remote. I didn't want to come," he said.

After graduating in 2012, Chen Botao took a stable job at the local aquatic products bureau in Xianghua town, Xichuan, about a 40-minute drive from the farm. His father, meanwhile, kept up a quiet campaign. Whenever university students came to the forest farm for visits or research, Chen Renfan would talk up the place, explaining the importance, hoping to attract educated young people to join.

"He has deep feelings for this place. If no young people come, it might decline," Chen Botao said of his father.

The son began to see the farm differently, not just as his father's workplace, but as his life's work.