BEIJING -- 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.