A circle of suburban parks built in the past five years are providing a "green shield" for Beijing, but more work is needed to make them attractive to residents, a senior official said.

There are now 81 parks along the capital's Fifth Ring Road and they occupy an area of 5,406 hectares, according to the Beijing Municipal Bureau of Landscape and Forestry.

"Due to the amount of work involved, the visual aspect is not as ideal as expected, and infrastructure construction is still lagging, and there is a limited range of tree species," said Lan Bincai, director of greenbelt construction with the bureau.