A press conference for a value evaluation report of the forest eco-system in Shanxi province is held in Taiyuan on June 28. [Photo/news.cn]

A total of 10.1 billion cubic meters of water, which would fill one fourth of the Three Gorges Reservoir and be worth 103.46 billion yuan ($15.59 billion), has been conserved by forests in Shanxi province.

It's the first time that Shanxi has completely evaluated its forest ecosystem, after a five-year effort, said Ren Jianzhong, director of Shanxi Forestry Department at a press conference in Taiyuan on June 28.

Shanxi started the evaluation work five years ago with the support of the Chinese Academy of Forestry, collecting continuous monitoring data from 13 forest ecological monitoring stations and researching seven eco-functions of the forest, including water conservation, air purification, carbon fixation and oxygen release.

According to the evaluation, the total eco-value of forests in the province in 2016 reached 317.26 billion yuan with the value of forest per hectare amounting to 63,700 yuan. The major functions of forests in Shanxi are water conservation and air purification, with the annual value totaling 103.46 billion yuan and 88.8 billion yuan respectively, accounting for 60.6 percent of the total value.

To directly show the ecological role of the forest, Zhang Yunlong, deputy director of Shanxi Forestry Department showed real-time data from Luya Mountain Nature Reserve at the press conference. The anion concentration and PM2.5 concentration in the nature reserve was 5,000 to 8,000 anions per cubic centimeters and 5.2 micrograms per cubic meter.

That's why people can breathe easily, and feel invigorated and relaxed when walking in the forest, said Zhang.

At present, forests cover 3.21 million hectares in Shanxi with a forest coverage rate of 20.5 percent, up by 2.47 percentage points compared with 2010. However, Shanxi ranks 22nd in China for its forest coverage rate, lower than the national average, and there are still barren mountains covering 2.18 million hectares which need greenery.

Based on the principle that the lucid waters and lush mountains are invaluable assets, Shanxi will now release an evaluation report every five years to gradually establish and complete the mechanism of forest eco-value transactions and further promote afforestation and forest protection.