Pines covering 7 million mu (470,000 hectares) in East China's Shandong province are under threat from pine wood nematode disease, the local forestry department said.

Currently, pines in 98,000 mu across 13 counties have already been infected by the disease, which is moving rapidly toward the western part of the province.

More must be done to bring the disease under control, it was agreed at a recent forestry conference.

The disease, also known as pine wood cancer, can kill a pine tree in 40 days, destroying huge swathes of pines within a short time. It was first detected in 1982 in eastern Jiangsu province and spread to neighboring Shandong in 1990.