Ahead of Tuesday's annual national tree planting day, Beijing's forestry department announced Monday that 3 million trees will be planted in 2013.

It will encourage residents to add to this quota by planting or adopting trees, or putting out decorative plants for festivals.

Beijing Municipal Bureau of Landscape and Forestry plans to set aside 3.88 square kilometers of land (approximately 359 standard soccer pitches) for tree planting. Also 889,000 trees and 11 square kilometers of lawns are ready for adoption, according to a press release.

For the first time, the city is supporting an ancient tree adoption program, offering 755 trees dating from the Qing Dynasty (1644-1912) for individuals or groups to sponsor.

Ju Zhaoming, an employee from Ritan Park, said the park has 44 of the 755 ancient trees, most of which are cypress.

"They are 200-300 years old. You sign a contract with us, and pay 10,000 yuan ($1,608) every year, and we do everything the tree needs, like watering and pest control," said Ju.

The National People's Congress made a decision in 2012 to ask every healthy Chinese citizen to plant three to five trees each year. People can also meet this quota by contributing to forestry works such as building firebreaks and paths. Adopting one ancient tree equals to planting 50 trees, while adopting three trees, 30 square meters of forest or six square meters of lawns also equals to planting one tree.

Residents can also meet the quota by donating to green foundations or putting decorative plants outside during festivals. If enterprises and government departments put 20 plants outside during festivals, this equals to planting one tree, and a donation of 60 yuan equals three trees.

Ma Jun, director of the Institute of Public and Environmental Affairs, said the announcement shows Beijing is pursuing a more flexible approach to tree planting, but whether putting decorative plants out is useful remains in question.

"Donating to environmental causes is a convenient way to protect the environment as this money can be used to hire people to plant trees and citizens do not need to plant on their own. However, putting plants outside cannot be compared to planting a real tree," said Ma.

"Decorative plants are only for festivals, but planting trees helps expand forests, which is necessary to balance and clean the ecological environment. It's unnecessary to bring these two things together," said Ma.

In 2012, 4 million trees were planted in Beijing, and 15.9 million saplings were cultivated, the bureau said.