NANJING, July 6 (Xinhua) -- With bonsai trees in various shapes and birds chirping in the garden, Wang Guangming skillfully attached a twig to the branch of a pine tree and then covered the twig with some cling wrap.

"The cling wrap cover is a new grafting technique I developed, which helps reduce the tree's growth time and creates more design possibilities," said Wang, 67, a farmer who has been growing bonsai trees for over 50 years in the Guzhuang Community of Rugao City in east China's Jiangsu Province.

"I'm not afraid that others will steal the technique from me. There's a lot behind it. Picking the right timing with the perfect temperature and humidity relies on years of experience," he said.

People in Rugao have traditionally grown bonsai trees, with the practice possibly dating back to the Tang Dynasty (618-907). Growing bonsai trees has changed Wang's life over the years.

"The alkaline soil here didn't produce a high grain yield, and we weren't even able to feed ourselves back in the early 1970s," he recalled.

In 1976, Wang and the villagers started to grow bonsai trees on a large scale. In the 1980s, they would go to other cities in the country to sell their trees, and some of them could earn an annual income of over 10,000 yuan (about 1,415 U.S. dollars).

The bonsai trees are therefore described by locals as the "green bank."

"Even if you don't sell a certain tree this year, you don't have to worry. You can sell it for a higher price for it will grow into a bigger tree with a better design," he said.

Now, Wang earns about 1.5 to 2 million yuan every year. "Growing bonsai trees is like drawing. It's an art," he said.

The younger generation is also joining the trade.

Liu Xiaofei, 35, turned to the bonsai tree growing business in 2007. "My parents grew bonsai trees when I was little, so I developed an interest at an early age."

"Big trees have a limited number of buyers as it takes longer to grow big ones, which have a higher price," he said. "So I decided to make miniature bonsai trees, which are easier to grow and therefore cost less. Moreover, small ones are more convenient to carry."

Last year, his company sold about 200,000 miniature bonsai trees. He is also creating ways of selling the trees by doing livestreaming sessions and developing a mobile phone app to connect farmers and buyers in the country.

The bonsai trees have also brought tourists to the community in recent years. Last year, the Guzhuang Community gained over 250 million yuan from tourism.

"You're not rich enough if you earn a million yuan. A rich farmer in Guzhuang has the aim of earning at least 10 million," said Zhu Songhui, Party chief of the community. "The bonsai tree is a cash cow for us, and we'll work harder to lead a better life."