Shanghai will reserve 3,500 square kilometers of land as ecological space, a forestry official said Thursday on a local radio program.

The goal is to make ecological space account for more than 50 percent of the land in Shanghai, according to a plan by the Shanghai Municipal Afforestation and City Appearance and Environmental Sanitation Administration.

Because green space is essential to quality of life, the administration will continue to keep the total amount of green space in the city constant even though specific areas might be reclassified for other uses in the future, said Meng Shujie, an administration press officer.

The administration plans to allocate 400 square kilometers for 21 country parks in the city's suburban districts, Lu Yuexing, the administration's director, said on the radio program.

The city has also expanded the ecological space within Inner Ring Road so most residents can find an area of green space larger than 3,000 square meters within half a kilometer of their homes or offices, Lu said.

Public green space also provides environmental benefits, said Dai Xingyi, a professor in the department of environmental sciences and engineering at Fudan University. "The public green spaces scattered around downtown effectively reduces the urban heat island effect," he told the Global Times. "They can help lower the temperature nearby and provide places for city residents to get away from the noise."

When planning ecological space, the administration needs to consider many factors, such as what facilities and buildings are nearby, to maximize its benefits and integrate it into the larger ecological system.

For example, Dai said it is unnecessary to build large parks around villas, where a great deal of green space already exists.

In addition, some residential areas might have greater need for facilities such as hospitals and schools.

Farmland can also be classified as ecological space. "Nowadays, the value of farmland is based too much on the crops it produces. In fact, there are multiple ecological benefits of farmland, which can provide habitats for some animals," Dai said.

Shanghai should expand the amount of ecological space, but residents and officials also need to think about ways to make full use of the space to ease the tension between development and preservation.