Wang Juan, 65, used to practice tai chi in her courtyard as a way of exercise. Now, she has found a better place - the forest.

Exercise in the forest, or forest therapy, has become a new fashion among older people, and according to one industry expert, it has the potential to grow into a new industry worth more than 1 trillion yuan ($146 billion), bringing tens of millions of job opportunities.

"Forest therapy integrates many industries including elderly care, tourism, culture, sports, experience and entertainment. It will constitute a large, highly dense and intertwined modern industrial cluster, cultivating an industry worth a trillion yuan, or even larger," said Liu Tuo, head of the Department of Rural Forestry Reform and Development of the National Forestry and Grassland Administration.

According to Liu, the sector's huge growth potential comes from the country's changing demographics.

"China has numerous patients suffering from chronic diseases and mental illness, and is becoming an aging society. In addition, the public have more spare time and increased salaries," he said, adding that "this is a great transformation opportunity for China."

According to data from the World Health Organization, by 2020, the tourism industry will account for 11 percent of global GDP, while the healthcare industry will be worth 12 percent.

As the country with the largest number of elderly people, China will certainly have enough potential clients. By the end of 2017, there were 241 million Chinese people, or 17 percent of the population, aged 60 or above. Of them, 158 million - more than 11 percent of the population - were 65 or above, according to data from the National Bureau of Statistics.

With people's rising living standards, forest therapy has become popular among elderly citizens. The experience offers a chance for people to get back to nature, and spend their remaining days among peaceful green trees. In addition, the fresh air, organic food and rich culture offered by rural living helps to offer a healthy lifestyle for body and soul.

Statistics from the National Forestry and Grassland Administration showed that in 2015 there were 2.3 billion visits to national forest tourism sites, and 1.07 million people made their living from the industry.

By 2020, the NFGA strives to build 200 demonstration forest cities, 1,000 forest towns, 10,000 forest parks, and to raise the annual visits in forest tourism to 2.5 billion.

According to analysts, the sector also helps provide work in areas with high levels of rural poverty.

Statistics from Firestone Inventing, a consulting company specializing in the medical industry, showed that by last October there were 374 forest therapy pilot programs across China. Most are located in Southwest, Northeast and Central China, areas which are rich in natural resources but tend to be economically underdeveloped.

"Forest therapy is an essential part of building a Healthy China," said Zhang Jianlong, head of the NFGA, adding: "The development of the industry not only increases employment, improves people's livelihoods, and enhances people's sense of well-being in a healthy life, but also meets the requirements of precise poverty alleviation and forestry supply-side structural reform."

Liu Tingfang, chairman of the committee of the international medical tourism department under the China International Exchange and Promotive Association for Medical and Health Care, agreed. "The tourism industry and healthcare industry are two key sectors for economic development. The medical tourism industry is the integration of the two sectors, and will become a new growth point for global economic development," he said.