BEIJING, March 12 (Xinhua) -- China's forestry authority has initiated an annual national campaign to encourage Chinese to go out in Spring to plant more trees and turn the country green.

A special banner has been placed on the front page of the website of the National Forestry and Grassland Administration, displaying the slogan "Where to go in spring? Plant trees and make China green."

On Tuesday, China's 40th Arbor Day, the administration and the National Greening Commission also sent messages to mobile phone users, encouraging them to plant more trees.

A day earlier, the first commemorative stamp in honor of Arbor Day was released in Beijing to mark the 40th Arbor Day.

The stamp, with a face value of 1.2 yuan, bears the image of a pair of hands which resemble the branches of a tree. Above that tree, a beautiful scenery features green leaves, a stream of water, mountains, birds and houses.

Liu Dongsheng, deputy director of the administration who attended the release ceremony, said Arbor Day had become an important occasion to arouse public awareness of green development.

According to a statement issued by the administration, China plans to add 6.73 million hectares of afforested areas in 2019 to further expand forest coverage.

The forest coverage rate of China has increased nearly 10 percentage points since the late 1970s, with the world's largest area of planted forests and an 80-percent expansion of forest areas, said Zhang Jianlong, director of the administration.

In 2018 alone, China planted 7.07 million hectares of new forests and treated more than 6.66 million hectares of degraded grasslands, according to a communique on China's afforestation conditions released Tuesday.

Participants from all walks of life took part in various voluntary tree planting activities last year, including ministers, generals, and leaders and cadres at all levels, the communique said.

Many government departments also took part in environmental efforts. In 2018, China's transport sector spent 8.79 billion yuan (about 1.3 billion U.S. dollars) on highway greening, afforesting 79,000 km of highway, while housing and urban-rural development departments constructed green passages, with per capita urban green park areas reaching 14 square meters, it said.

Chinese people have also been keen to participate in a virtual tree planting project in the mobile payment app Alipay. The project rewards low-carbon acts such as renting a bike or taking the bus with "energy" to "water" virtual trees, and the organizers will plant a real tree in deserts in China when a virtual tree grows up.

A study using data from NASA satellites confirmed China's efforts on afforestation.

Data shows that China and India are leading the increase in land greening and concludes that the "effect comes mostly from ambitious tree-planting programs in China and intensive agriculture in both countries."

In line with NASA's data, the greening rate of many Chinese cities including Beijing, Shanghai, Nanchang and Shenzhen saw an increase instead of a drop amid rapid urbanization, according to an ongoing study of the Chinese Academy of Forestry.

Beijing has launched large-scale afforestation projects over the past few years, leading to an increase of 10 percentage points in forestry coverage in plains in just four years, the study showed.

Besides land greening efforts, afforestation projects in Beijing also took into consideration forest quality and animals' needs by choosing plant and tree species with long life-spans or those that can provide food for wild animals.

"In the past, we only considered the needs of human beings. Now, we stress more on biodiversity," Deng Naiping, head of the Beijing Municipal Forestry and Parks Bureau, was quoted by Beijing Daily as saying.

Deng said animals and human beings can share green space thanks to scientific tree species choices, which will contribute to harmonious coexistence between man and nature in the long term.

Under a long-term afforestation plan, China expects to increase its forest coverage rate to 23.04 percent by 2020, and to 26 percent by 2035, as part of the plan to build a Beautiful China.