"The trees you helped fund all those years ago have grown into a vast forest. When will you come to see them? I really want to meet you again," said Yin Yuzhen, a national model worker in China, in a heartfelt video message to Ronald Sakolsky in the U.S.

Across the Pacific, 69-year-old Sakolsky was deeply moved by the video. He replied that he would do his best to make the trip and hoped to plant a tree with Yin. The two have agreed to meet in China in the near future.

In 1985, Yin married into Salawusu village in Uxin banner, Ordos, north China's Inner Mongolia Autonomous Region. Situated deep in the heart of the Mu Us sandy land, the village was surrounded by endless dunes.

Yin knew that the only way to tame the sands was to plant trees. In 1986, she sold one of her family's sheep to buy 600 saplings, which she planted around her home. Soon after, a fierce sandstorm struck, leaving fewer than 10 trees alive. But Yin refused to be discouraged.

"If around 10 survived, later it might be 100, then 1,000," she recalled.

Undaunted, she and her husband Bai Wanxiang headed deep into the sand dunes, bringing saplings and tools along. For 40 years, a roughly 2-meter-long steel rod was Yin's trusted tool. She would jab it into the sand to make a hole, drop in a sapling, water it, and press the soil firmly with her foot. After decades of relentless use, the rod had worn down by about 67 centimeters.

Over the past four decades, government-led efforts and desertification fighters like Yin have driven a dramatic transformation of the landscape. More than 70,000 mu (about 4,667 hectares) of sandy land around Yin's home have been reclaimed, with over 8 million trees planted.

Today, about 85 percent of the Mu Us sandy land in Uxin banner — around 8.4 million mu — has been brought under control, and forest coverage has risen to 32.92 percent.

In 1999, Sakolsky, who was then teaching at a school in central China's Henan Province, happened to see a TV show about Yin's efforts and was deeply moved. He raised $5,000 through a foundation to support Yin's tree-planting work.

Yin was stunned when she received the donation.

"A complete stranger had raised such a large sum for me without even checking who I was. I had to make sure those trees thrived. I couldn't let that trust go to waste," she said.

"With more people worldwide showing concern, I came to understand that this is a dream shared by all humanity," Yin said.

Further down the tree-lined road stands a stone monument engraved with the words "Citizens of Earth." On its reverse side are the names of supporters from both China and abroad, each of whom contributed to the woodland in their own way.

Yin's perseverance has inspired more than 240 households in the surrounding areas to take up tree planting, with each planting over 3,000 mu of forest.