Cheng talks with colleagues during a nature education tour in Pingtan. [Photo/CHINA DAILY]

In college, he majored in environmental engineering. After graduation, he joined a financial company in Taiwan and also worked part-time, planning family day activities for enterprises and teaching children nature education courses.

Hoping to find a career on the other side of the Straits, in December 2016, Cheng left the financial company and took part in a visit to entrepreneurial bases for Taiwan residents in mainland cities, such as Fuzhou, Xiamen and Pingtan in Fujian, as well as Shanghai.

He was impressed by Pingtan, which is only 68 nautical miles from Taiwan's Hsinchu city, making it the nearest mainland location to the island.

During the visit, Cheng saw the construction of the Pingtan Haixia Rail-Road Bridge that connects Fujian's capital Fuzhou and Pingtan. The bridge opened to traffic last year, cutting travel time between the two areas from two hours to about 30 minutes.

At the beginning of 2017, Cheng and his partner came to Pingtan to find work. With years of experience in event planning, Cheng worked with a local homestay to organize small group activities.

He got to know Mao Xiujuan, whom he married later, during one such activity in August 2017. As secretary-general of the Pingtan Environmental Volunteers Association, Mao asked Cheng to organize a volunteer activity for children about lake protection.

As they worked together, Mao discovered that Cheng was good at helping children get close to nature and that his philosophy of nature education coincided with her own ideas of environmental protection. Cheng also discovered that Mao shared the same interests and joined her volunteer association.

Mao said that Pingtan's grasslands, beaches and forests could be easily integrated with Cheng's environmental education philosophy.

Nature education was not popular in Pingtan at the time, but Cheng saw it as an opportunity. In 2018, he founded a company with Mao that offers science courses for children to learn about nature.

He gradually opened up the market by working with after-school tutoring agencies and kindergartens.

"Today's children are mostly raised in cities and are tied to mobile phone games at home. Through a series of courses, I want to ignite their passion for exploring nature," he said.

With his childlike and friendly way of talking, the students call Cheng "forest teacher". He does not fill their heads with facts, but instead encourages them to experience nature on their own.

"I let them use their eyes, ears, noses, mouths and hands to explore nature in a safe way. For example, I get them to smell grass and dirt, or touch the bark of a tree with their cheeks," he said.

The children are also asked to find things such as a feather or an insect, lie on the ground to observe the sky and learn to grow strawberries.

Once, a little girl who was taking his class for the first time was so shy that she didn't even dare to touch a flower. Cheng patiently showed her how to touch and smell flowers and gave her the courage to follow other children.

"I was so happy that after she'd taken my class for the sixth time, she was able to come on stage holding a cockchafer and tell the others about the insect. A child's trust and smile are beautiful things, just like nature," he said.

"Nature's love is selfless and beautiful, and I want to pass that on to the children. I hope that more green areas are protected so that they can still visit them when they have grown up."

Cheng also spends a lot of time participating in volunteer activities. He has engaged in activities to protect the coastline and has volunteered to pick up garbage on beaches, sorting and weighing what he collects to produce data about the issue.

Cheng proposed to Mao last year. He said that he came to Pingtan for a career, but he never thought that he would also meet his wife and find a home.

Yang Jie contributed to this story.