Nitrogen emissions in smog threatens to 'massacre' world's forests: Chinese scientists

Thick smog could kill off most southern China's natural forests within decades and threatens trees around the world unless nations take action, say scientists.

A 13-year study by Chinese scientists has revealed strong evidence to show the danger is being caused by nitrogen emissions in the atmosphere.

"It is a silent massacre," said Dr Lu Xiankai, associate researcher at Chinese Academy of Sciences' South China Botanical Garden in Guangzhou and a lead scientist of the project.

At one observation point in Dinghu Mountain, Zhaoqing , more than a dozen plant species growing below an old tree had died off until only one or two were left, and the tree could be next to go if the "nitrogen fallout" from smog continued, Lu said.

"Immediate measures must be taken to reduce air pollution, especially nitrogen emissions," Lu said.

"If the situation remains as it is, most forests in southern China will be destroyed within decades. But the impact is not limited in China. The problem will have a ripple effect around the world."