China now boasts the world's largest expanse of planted forest - over 69 million hectares - the head of the State Administration of Forestry and Grassland told an international congress in Beijing on Tuesday.

As the area of planted forest continues to grow, more importance is being attached to ecological functions, Zhang Jianlong, the head of the administration, said at the opening ceremony of the fourth International Congress on Planted Forests. 

Zhang said China began planting trees in felled natural forests in the 1950s, mainly to ensure timber supplies. But today, planted forest mainly contributes to the country's construction of ecological civilization.

'The country has been attaching more importance to planted forest's role in the recovery of vegetation, degraded areas and landscapes, and the protection of biodiversity and water conservation," Zhang said.

However, he said, there are some problems with the country's planted forest, including a lack of biological diversity, and low ecological functions and economic benefit.

In addition to strengthening scientific research and innovation, Zhang also vowed to promote international exchanges and cooperation so that countries can share their experiences in promoting planted forest.

The congress, themed "Planted Forests - A Solution for Green Development", will end on Saturday.