China's forests helped reduce carbon dioxide emissions by more than 5 billion tons from 1980 to 2005, a top Chinese forestry official said Wednesday.

"China has been successful in fixing large volumes of carbon dioxide through forest protection and development," Zhu Lieke, deputy head of China's State Forestry Administration, told a press conference during the U.N. climate change conference in the Danish capital.

From 1980 to 2005, China's forests absorbed carbon and reduced emissions by a total of 5.11 billion tons, he said. Carbon emissions from forests have been reduced through rational control of logging activities, reduction of deforestation and the control of forest fires and pests and diseases, he said.

China has announced it aims to reduce the intensity of carbon dioxide emissions per unit of GDP in 2020 by 40 to 45 percent against 2005 levels.

"Conservation of forests, reduction of deforestation, improvement of forest quality and promotion of sustainable forest management have become the inevitable choice to tackle climate change," Zhu said.

In the recent decade, China has invested more than 70 billion U.S. dollars in afforestation, vegetation restoration and the promotion of sustainable forest management, he said.

"China will strive to increase its forest area by 40 million hectares by 2020 from the 2005 level," Zhu said.