A Chinese woman who has spent four decades greening a stretch of Inner Mongolia desert has tracked down the American who donated $5,000 to her afforestation work 27 years ago, after a video plea she posted online in early May spread widely across Chinese social media.

Yin Yuzhen, a national model worker who has voluntarily planted trees in the Mu Us Sandy Land with her husband since the 1980s, had long sought to thank the donor — identified as Ronald Sakolsky, 69, a retired high school teacher in the United States — but had lost contact with him. In her video, she invited him to return to China, saying the $5,000 he contributed through an American foundation had since grown into a large forest.

The appeal reached Sakolsky through former students and Chinese colleagues, who contacted him by text and email to let him know Yin was looking for him. The two spoke by phone on May 17. A recording of the call, released online the following day, showed Yin inviting Sakolsky to visit and Sakolsky saying he hoped to return and plant a tree alongside her.

"At the most difficult time, [Sakolsky] gave me a large sum of money, which allowed me to buy so many high-quality saplings," Yin said. "I have never forgotten and will never forget it."

Sakolsky described the reconnection as "a miracle" and called Yin "a truly amazing woman". He said he had long hoped to see the saplings he helped fund grow into a dense forest.