China began to protect its forests in 1998 after facing timber shortages of around 60 million cubic meters per year.

The country depended on imported timber from the US, Russia, New Zealand and timber-producing countries in Southeast Asia and Africa.

A study by the State Forest Administration shows that its wood demand is expected to rise to 800 million cu m by 2020.

The government plans to have more than 30 percent of its buildings at that time considered environmentally friendly, and 20 percent of new urban building construction eco-friendly by the end of this year.

Deng Huafeng, a professor at Beijing Forestry University, said other conditions that have stimulated China's US hardwood imports include the government's protection of its own still-limited wood resources, as well as dwindling timber shipments from Brazil, Myanmar, Ghana and Gabon, because of tightening export restrictions there over the past four years.

US hardwood exports to Southeast Asian countries have also seen strong growth with lumber sales rising 16 percent year-on-year to $249 million in 2014.

Vietnam is the largest regional buyer with orders worth $184 million, with sales to Indonesia, Malaysia and Thailand also remaining strong.