Beijing orchard farmers are boosting the city's economy and job market by finding valuable uses for land under their trees, authorities say.

More than 23,526 hectares, which had been left empty, is now used to grow mushrooms, traditional Chinese medicine ingredients and for keeping poultry, according to the Beijing Landscape and Forestry Bureau.

Authorities say that by the end of last year this industry - known in Chinese as the industry under the green - was worth 1.9 billion yuan ($306.5 million) and provided more than 300,000 jobs.